Trajectories and determinants of left ventricular ejection fraction after first myocardial infarction in current era of primary coronary interventions

Background

Left ventricular ejection fraction (EF) is an independent predictor of adverse outcomes after myocardial infarction (MI). However, contemporary data from the PCI era of MI therapy on trajectories and determinants of EF are scarce.

Purpose

The present study aimed to describe the epidemiology of systolic dysfunction and EF recovery among consecutive patients hospitalized for their first MI.

Methods

Data from a single-centre prospectively-designed AMBITION registry of consecutive patients hospitalized for MI between years 2017 and 2021 at a large tertiary cardiology centre were utilized.

Results

Out of 1593 patients in the registry, 1065 were hospitalized for MI type I and had no previous history of heart failure (HF) or coronary artery disease. Revascularisation was performed in 93.5% of patients: 901 (84.6%) underwent PCI, 89 (8.4%) CABG and 6 (0.6%) both. At discharge, EF<40% was present in 238 (22.3%), EF 40–50% in 326 (30.6%) and EF >50% in 501 (47.0%), respectively. Patients with EF<40% were more often those who suffered subacute and anterior STEMI, had higher heart rate at admission and higher maximal troponin level, and more often HF signs requiring intravenous diuretic therapy (Table 1). In the multivariate Cox analysis, EF<40%, together with age, glomerular filtration rate, glycemia level, clinical signs of HF, and atrial fibrillation were associated with increased mortality risk. Among subjects with EF<40%, the control follow-up EF determined on a median 153 days (IQR 101–407) after discharge was available in 166 patients. Among these, systolic function recovered to EF>50% in 38 (22.9%) and improved to EF 40–50% in 45 (27.1%). Improvement in systolic function to EF>40% was predicted by lower severity of coronary artery atherosclerosis (GENSINI score), by higher discharge EF, by the lower leukocyte count, the absence of atrial fibrillation during MI hospitalization and glycemia level (Table 2). Recovery of systolic function was associated with lower mortality risk (log-rank p=0.012).

Conclusion

In the current era of primary coronary intervention, only 22% of patients after the first MI have EF below 40%. Of them, EF improves in 50%, and full recovery is observed in 23% of patients. Severity or coronary atherosclerosis, inflammatory response to MI, atrial fibrillation and glucose metabolism may all affect EF recovery. These observations provide novel therapeutic targets for EF recovery.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health, Czech Republic

Cardioneuroablation focused on the atrioventricular node: a comparison of right and left atrial approach

Background

Radiofrequency catheter ablation of posteromedial left ganglionated plexus is a critical step to eliminate the vagal input to the atrioventricular node (AVN) for the treatment of symptomatic episodes of functional AV block. This ganglionated plexus can be effectively targeted from the coronary sinus (CS) or from the endocardial aspect of the right (RA) and left (LA) atria.

Purpose

We investigated the effect of ablation at individual sites on the suppression of parasympathetic modulation of AVN.

Methods

The study included 20 patients (age: 42±13 years, 45% males) who underwent cardioneuroablation in general anesthesia. Posteromedial left ganglionated plexus was ablated from [1] the CS (proximal 2-cm segment), [2] the RA aspect (between the fossa ovalis and inferior vena cava), and [3] the LA aspect (middle bottom part adjacent to inferior rim of fossa ovalis). Patients were randomly (1:1) assigned to CS-to-RA or RA-to-CS ablation order. LA ablation was always the last step. The response to extracardiac vagus nerve stimulation (ECVS; 50 Hz, 0.05 ms, 1 V/kg [<70V], 5 s) while atrial pacing (100 bpm) was recorded at baseline and after each ablation step. The number of non-AV-conducted beats during the ECVS was considered a measure of AV nodal denervation. Both right and left vagus nerves were sequentially stimulated and the stronger response of the AV node was taken into account.

Results

Temporal development of outcome measure with the progression of ablation is shown in Figure 1. CS ablation resulted in much stronger AV nodal denervation compared to RA ablation (P=0.02). However, RA ablation still provided some effect on top of CS ablation. The combination of CS + RA ablation resulted in complete AVN denervation in 8 (40%) patients. Subsequent LA ablation increased the number of denervated patients to 14 (70%). Two more patients were subsequently denervated by ablation elsewhere. In four patients, AVN denervation was not achieved but their responsiveness to ECVS was significantly suppressed compared to the baseline.

Conclusions

All ablation clusters targeting posteromedial ganglionated plexus convey complementary effects. Biatrial cardioneuroablation seems essential for efficacious suppression of parasympathetic modulation of AVN.

Funding Acknowledgement

Type of funding sources: None.

Importance of bilateral vagus nerve stimulation for effective atrioventricular node denervation during cardioneuroablation

Background

The progression of parasympathetic denervation of the atrioventricular node (AVN) during cardioneuroablation (CNA) can be evaluated by extracardiac vagal stimulation (ECVS). The right vagus nerve is usually used for stimulation (R-ECVS) because the right jugular vein is easily accessible. However, the AVN node is predominantly under the control of the left vagus nerve.

Purpose

To highlight the importance of left vagus stimulation (L-ECVS) for effective AVN denervation.

Methods

Both R-ECVS and L-ECVS (frequency: 50 Hz; pulse width: 0.05 ms; output 1 V / 1 kg; max. 70 V, duration 5 s) was attempted in 80 patients (age: 41±12 years, 45% men) undergoing CNA with stepwise strategy consisting of ablation of right anterior ganglionated plexus (RAGP) followed by ablation of posteromedial left ganglionated plexus (PMLGP). The study objective was the AVN response to L-ECVS (evaluated as the max. R-R interval during stimulation train) at the point when AVN non-reactivity to R-ECVS was achieved.

Results

A total of 59 patients were suitable for the analysis. Of the remaining 21 patients, left (n=14) or right (n=2) jugular veins were not accessible, AVN non-reactivity to L-ECVS was achieved before non-reactivity to R-ECVS (n=4), or AVN denervation was not achieved at all (n=1). At baseline, the AVN response was identical for R-ECVS (max. R-R median: 6.9 s, interquartile range [IQR]: 5.7–8.2 s) and L-ECVS (median: 7.1 s, IQR: 6.0–8.3 s), P=0.44. AVN non-reactivity to R-ECVS was present already at baseline (n=2); was achieved after ablation of RAGP (n=14), after ablation PMLGP (n=38), or after extensive ablation (n=5). At the point of AVN non-reactivity to R-ECVS, the response of AVN to L-ECVS was as follows: none (n=25), 2: 1 AV block (n=13) or complete AV block (n=21). The corresponding median of max. R-R interval was: 1.2 s, IQR: 0.6–4.8 s distributed as shown in Figure 1.

Conclusions

In 34/59 (58%) patients, significant AVN response to L-ECVS persists after reaching AVN non-reactivity to R-ECVS. Stimulation of both vagal nerves tightens the procedural endpoint and may increase the clinical efficacy of CNA, especially in patients with dominant AVN disorder.

Funding Acknowledgement

Type of funding sources: None.

Long-term toxicity of radiosurgery for ablation of ventricular tachycardia

Introduction

There is a rising interest in using radiosurgery to modify arrhythmogenic substrate in patients with recurrent VT. However, data on the safety are still inadequate.

Purpose

This is update of toxicity evaluation based on the compilation from our case series, NIRA-VT and STAR-VT.

Methods

Between 2014 and March 2021, 36 patients (33 male, 3 females; mean age 66±10 years) with structural heart disease (ischemic cardiopathy, dilated cardiopathy or fibroma associated scar) from two electrophysiology centers in the Czech Republic (Trinec, Prague) underwent radiosurgery for recurrent VT.

Radiosurgery was performed after at least one failed catheter ablation for VT. The critical part of the VT substrate was identified by electroanatomic mapping using a combination of voltage mapping, pace mapping, and activation mapping; and it was marked on a contrast-enhanced computer tomography study as a CTV. In NIRA-VT trial, CTV included scar based on PET/CT evaluation. Radiosurgery system with real-time motion tracking using the tip of the electrode of an indwelling defibrillator as a fiducial marker was used. A total radiation dose of 25 Gy was delivered to the ablation target in a single session during free breathing. Radiation-induced toxicity was evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Only patients with follow up longer than 6 months were included in long term radiation related side effects evaluation.

Results

The mean CTV and PTV were 26±11 ml and 41±22 ml respectively. No patient exhibited acute (up to 3 months) elevation of troponin, pericardial effusion, or a decrease in left ventricular ejection fraction from baseline. Four patients developed acute mild nausea, which waned after antiemetic drugs. Long-term radiation related side effects were evaluated in 19 patients. Two patients (11%) presented radiological signs of lung fibrosis in small area in close distance from PTV. There was no significant decrease in left ventricular ejection fraction during follow up. Six patients (33%) gradually developed significant progression of known mitral regurgitation after SBRT, two (11%) of them had to undergo mitral valve replacement (grade 4 toxicity). Two cases of esophagitis (12%) were seen with one radiation toxicity related death (grade 5 toxicity) due to the unresectable esophagi-pericardial fistula (6%).

Conclusions

Our data indicate the feasibility of radiosurgery, majority of patients presented no/mild radiation related toxicity and decrease of VT burden. However, we have seen three cases of grade 4,5 toxicity. To further investigate long-term safety and efficacy of radiosuergery for VT, enrolling into a randomized prospective study is in progress.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020

Bipolar ablation of refractory ventricular arrhythmias using a novel dedicated adapter. A multicenter study

Background

Bipolar ablation (BA) recently emerged as an alternative for treatment of ventricular tachycardia (VT) and premature ventricular contractions (PVC) refractory to a classic unipolar ablation (UA). Data on the use of available BA systems is lacking.

Purpose

To determine feasibility, safety and efficacy of a novel BA adapter in consecutive patients with refractory VT/PVC undergoing repeat ablations.

Methods

The study group consisted of consecutive patients with VT/PVC after failure of at least one standard UA who underwent redo procedures performed with a support of BA at six European centers. A second ablation catheter was connected in the position of a return electrode using a novel BA adapter.

Results

Between March 2021 and March 2022 a total number of 19 patients after failed ablation attempts underwent redo procedure using a novel BA adapter (17 males, age 61±11, number of prior ablation attempts 2,5±1,6; range 1–7). The main indication for redo ablation was recurrence of frequent PVC (n=10), VT (n=8) or electrical storm (n=1). Fifteen patients underwent combined UA+BA procedure during redo ablation, whereas 4 remaining patients underwent BA only. Two patients required epicardial access. Mean procedural time was 157±77 minutes. The mean BA time was 367±245s (power 32±9W) and mean UA time was 349±290s (power 43±6W). Apart from 1 anticipated AV block there were no major complications. Minor complications included char formation at 8mm tip electrode and steam pop without sequalae in one VT patient. BA+UA led to acute elimination of clinical PVC/VT in 18 patients. In the remaining 1 patient no effect on clinical VT during UA+BA was observed. The follow up lasted 4±3 months. Six (75%) VT patients remained arrhythmia-free and significant PVC burden reduction was achieved in nine (90%) PVC patients during follow-up. One patient treated for electrical storm experienced a single VT episode after 11 months. One patient after initially failed UA+BA underwent successful bipolar reablation after 2 months.

Conclusions

Bipolar ablation of refractory ventricular arrhythmias using a novel dedicated adapter is feasible, seems safe and effective. These encouraging preliminary results need to be confirmed in properly designed prospective trials.

Funding Acknowledgement

Type of funding sources: None.

Determinants of impaired coupling of right ventricle to hemodynamic load in advanced HFrEF

Background

The mechanisms and consequnces of impaired right ventricular (RV) dysfunction and impaired RV-pulmonary artery (PA) coupling in advanced heart failure (HF) poorely understood.

Purpose

To compare RV-PA coupling parameters in patients with advanced HFrEF, PAH and in controls to ellucidate determinants and prognostic impact of RV-PA uncoupling in HFrEF.

Methods

260 pacients with advanced HF (NYHA 3.0±0.5, 40% CAD, LVEF: 23±10%, 87% males, BMI: 28±4.5 kg/m2, BNP: 1238±982 pg/ml), 39 controls and 21 PAH patients underwent lab tests, ecocardiography, right heart catheterisation and equilibrium gated blood pool SPECT to precisely measure cardiac volumes. RV End-systolic elastance (Ees) and Effective arterial elastance (Ea) were calculated by single beat method. Patients were longitudinally followed for occurrence of adverse outcome (urgent Tx, LVAD or death without Tx/LVAD).

Results

PAH patients had higher PA pressures and more dilated RV than HFrEF and controls. Despite of that, RV-PA coupling, reflected by Ees/Ea ratio, was more profoundly reduced in HFrEF than in PAH (Figure). While RV contractility (Ees) was augmented by increased afterload in PAH, such augmentation was absent in HFrEF. At follow-up (median 258; 53–763 days), 69% of HFrEF subjects experienced adverse event (17% death, 24% urgent HTx, 28% LVAD). In HFrEF, RV-PA coupling was strongly predictive od adverse outcome, more than RV EF%, RV EDV or RV Ees. The strongest predictors of reduced RV Ees/Ea ratio in HFrEF were in descending order: RV EF, RV EDV, PA systolic/systemic systolic pressure ratio (PAs/SBP), PAWP, heart rate, PA compliance, RA mean pressure, PA mean pressure, BNP level, SBP, PAs, Tri Reg grade, Non-CAD etiology of HF, Mi Reg grade, PVR, RV dyssynchrony, absence of ACEi/ARB/S-V (GLM model, all p<0.001). RV Ees/Ea ratio correlated with PAs/SBP ratio, that reflects systolic ventricular interdependence. Invasive PAs/SBP predicted outcome and closely correlated with non-invasive estimation of PAs/SBP.

Conclusion

Despite having less PH and smaller RV, RV coupling is more impaired in HFrEF than in PAH due to absence of RV contractility enhancement. Higher RV volume, heart rate, tricuspid regurgitation, lower PA compliance, higher PAWP and systolic ventricular interdependence (PAs/SBP) are main determinants of RV PA decoupling in HFrEF. Elevated PA systolic pressure but low systemic BP (high PAs/SBP ratio) is associated with poor RV-PA coupling and prognosis.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): AZV NU20-02-00052, AZV NU21-02-00402

Cardioneuroablation in patients with a prior pacemaker implant

Funding Acknowledgements

Type of funding sources: None.

Background

Cardioneuroablation (CNA) is an alternative therapeutic method for patients with functional bradyarrhythmias, who are otherwise candidates for permanent pacing. In a specific clinical scenario, CNA can also be a treatment option for patients with already implanted pacemakers.

Purpose

We investigated whether CNA could substitute permanent pacing in selected patients in whom pacemaker is associated with complications, technical failures, or decreased quality of life.

Methods

Among 160 patients who underwent CNA by radiofrequency energy between 2014 and 2022, there were 13 patients (8%) with a pacemaker in whom CNA was indicated as a "substitute" treatment. The reasons were as follows: lead failure (n = 6), recurrent decubitus of the device pocket (n = 1), infective endocarditis (n = 1), recurrent syncope even after pacemaker implantation (n = 1) and discomfort associated with the implanted device (n = 4). In 4 patients, the pacemaker was explanted shortly before CNA because of serious complications. Biatrial CNA was guided anatomically with the use of a 3D mapping system and intracardiac echocardiography. Empirical sites of ganglionated plexi were targeted. The procedural endpoint was unresponsiveness of sinus and AV nodes to extracardiac vagal nerve stimulation.

Results

Patients (n = 13, 77% male, age: 41 ± 12 years) had a pacemaker implanted 11 ± 7 years ago. They responded to atropine (2 mg IV) administration by accelerating the sinus rhythm by 55 ± 33%. CNA was technically successful and uncomplicated in all of them. During the follow-up of 29 ± 16 months (range 6 - 56 months), 2 patients (15%) had a recurrence of syncope. In both, the syncope was reproduced by tilt testing and classified as a pure vasodepressor event. In the remaining patients, the follow-up was uneventful. Elective explantation of the pacing system has so far been performed in 3 of 9 patients, while this is planned in others after reaching a sufficient length of post-procedural follow-up.

Conclusions

CNA is an effective and safe method, which is not only an alternative to the pacemaker implant but can also be used in patients with functional bradyarrhythmias, and previously implanted pacemakers who experience significant adverse events associated with the pacing system.

Heart rate acceleration during cardioneuroablation is a weak predictor of significantly reduced parasympathetic modulation of sinus node

Funding Acknowledgements

Type of funding sources: None.

Introduction

Ablation of superior parasympathetic ganglia is associated with acceleration of sinus rhythm (SR). This has been considered a favorable sign during cardioneuroablation (CNA) for the treatment of functional bradyarrhythmias.

Aim

We studied whether the relative increase in SR frequency (DeltaSR) during CNA is a reliable predictor of significantly reduced parasympathetic modulation of the sinus node (SAN).

Methods

In patients undergoing CNA under general anesthesia, the gradual reduction in parasympathetic modulation of SAN during the procedure was assessed by extracardiac right vagal nerve stimulation (ECVS). The response to ECVS was quantified by the ratio of the maximum P-P interval (induced by ECVS) and the baseline SR cycle length (MaxPPratio). The ECVS was performed repeatedly after partial ablation steps, and therefore several pairs of DeltaSR and MaxPPratio values were obtained in the course of the single procedure. A MaxPPratio <1.5 was arbitrarily chosen as the criterion of significant attenuation of vagally induced responses. The optimum dichotomy of Delta-SR for the prediction of the MaxPPratio <1.5 was found according to the criterion of the minimum distance of the ROC curve from the point (0; 1).

Results

The study included 64 patients (mean age: 42 ± 16 years, 48% men). A total of 188 intraprocedural pairs of DeltaSR and MaxPPratio (2.9 ± 2.1 pairs per procedure) covering the wide distribution of their values (19 ± 14 bpm for DeltaSR and 2.9 ± 2.8 for MaxPPratio) were obtained. One half of ECVS tests (51%) met the criterion of MaxPPratio <1.5. In the analysis of receiver operating characteristic, DeltaSR as a predictor of significantly reduced parasympathetic modulation of SAN showed an area under the curve (AUC) of 0.69 with 95% confidence interval (CI) of 0.62 - 0.77 (Figure). The optimum cut-off (DeltaSR ≥20 bpm) had a sensitivity (SENS), specificity (SPEC), positive (PPV), and negative predictive value (NPV) of 61%, 78%, 75%, and 66%, respectively.

Conclusion

Acceleration of SR during CNA is not a relevant surrogate of significantly reduced parasympathetic modulation of SAN. Elimination or significant suppression of responses of SAN to ECVS serves as an excellent procedural endpoint that might contribute to the favorable clinical outcome of the CNA.

Accuracy of non-invasive anatomical lead localization in CRT patients: BSPM vs 12-lead ECG

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant agency AZV, Ministry of Health of the Czech Republic

Background

Non-invasive, inverse ECG (iECG), estimating the cardiac activation from ECG signals, may be useful both to support CRT implant and optimization. However, most iECG strategies require a 32-250 electrode body surface potential mapping (BSPM), limiting their clinical utility.

Objective

This proof of concept study evaluates the accuracy of our novel PaceView iECG method to localize the LV/RV pacemaker lead to the cardiac anatomy using either a 96-electrode BSPM or the 12-lead ECG.

Methods

PaceView generates activation sequences in combination with the equivalent double layer source model to simulate the corresponding ECG signals. An initial activation sequence is iteratively optimized to match simulated and measured ECG signals. A BSPM with 96 electrodes and CT were recorded for every patient with implanted CRT. The CT was used to create patient-specific heart/torso model and to localize the ECG electrodes and CRT leads. From a BSPM, 9 signals were selected to obtain the 12-lead ECG. Both BSPM and 12-lead ECG were used to localize the RV/LV lead as the earliest ventricular activation site.

Results

In this study 14 consecutive patients with dilated cardiomyopathy were enrolled: mean age 58±9 years, 7 females. The localization error for the RV/LV lead was 10.4±5.4 (max 22) / 11.3±5.5 (max 20.4) mm using the 12 lead ECG and 11.7±6.1 (max 26.2) / 13.5±5.8 (max 24.5) mm for the BSPM. The time used for a 3D activation map computation was 0.9-1.8 s.

Conclusion

Our preliminary results show that the non-invasive lead localization error, using the 12-lead ECG, is small and comparable with a 96-lead BSPM. Therefore PaceView might be clinically beneficial, by actively localizing the LV/RV pacing sites during CRT implant, and optimize AV or VV delays at CRT follow-ups.

Acute change of cardiac autonomic regulations after thermal and non-thermal pulmonary vein ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Pulmonary vein isolation (PVI) by thermal energy (radiofrequency energy or cryoenergy) results in collateral ganglionic plexi ablation. On the contrary, pulsed electric field (PEF) energy presumably spares neural tissue.

Purpose

We investigated and compared the effect of PVI on parasympathetic input into the sinus node (SAN) and AV node (AVN) when four different ablation strategies were used.

Methods

A study enrolled 49 patients who underwent PVI in general anesthesia (age: 57 ± 13 years, 71% males). In 17 patients, point-by-point radiofrequency energy delivery by the irritated-tip catheter was used for ablation while 7 patients were ablated using a second-generation cryoballoon catheter. In 7 patients, PEF energy was delivered using a single-shot Farawave catheter while 18 patients were ablated using Sphere9 lattice-tip catheter (Affera, Inc.); both subgroups with manufacturer-specific PEF settings. Before and after PVI, the responsiveness of the SAN and AVN was assessed by extracardiac vagal nerve stimulation (ECVS) via a diagnostic catheter in the right internal jugular vein. Five-second stimulation trains were delivered with a frequency of 50 Hz, pulse width of 0.05 ms, and output of 1 V/kg (<70V) both in sinus rhythm and during atrial pacing. Substantial reduction of response to ECVS was arbitrarily defined as a maximum induced pause of <1.5 seconds.

Results

At baseline, physiological response to ECVS (long sinus arrest and/or AV block) was demonstrated. After PVI, a substantial reduction of SAN response was observed in 21/24 (88%) patients after thermal PVI and 7/25 (25%) patients after non-thermal PVI (P = 0.0001). Similarly, a substantial reduction of AVN response was observed in 21/24 (88%) patients after thermal PVI and 9/25 (36%) patients after non-thermal PVI (P = 0.0003). The Figure shows on the continuous scale the post-PVI pauses in sinus rhythm (maximum P-P interval) and atrial pacing (maximum R-R interval) induced by ECVS.

Conclusion

Vagal responses of SAN and AVN are preserved in most AF patients after non-thermal PVI. This contrasts with the much stronger effect of thermal PVI. Whether this may influence the clinical outcome of AF ablation procedures remains to be investigated in future studies.

Stereotactic body radiotherapy for refractory ventricular tachycardia: the overall czech experience

Funding Acknowledgements

Type of funding sources: None.

Background

Catheter ablation (CA) is a well-established treatment strategy for the management of drug-refractory ventricular tachycardia (VT) in patients with structural heart disease. Stereotactic body radiotherapy (SBRT) was proposed recently as a treatment option for cases of failed CA.

Purpose

This study reports overall experience with the SBRT from two Czech centers.

Methods

Since 2014, we enrolled consecutive patients who underwent at least one prior CA for recurrent scar-related VT and had subsequent VT recurrences due to inaccessible substrate. Single-session SBRT for VT was performed without the use of general anesthesia or sedation. A dose of 25 Gy was delivered.

Results

The study investigated 33 patients (3 women) with a mean age of 66 ± 9 years. Underlying heart disease was ischemic (58%) and nonischemic (39%) cardiomyopathy; one patient had large cardiac fibroma. The mean left ventricular ejection fraction was 31 ± 8%. Seventy-six percent of patients were on amiodarone. Before SBRT, they underwent a median of 2 (IQR: 1-3; range: 1-5) CA that included epicardial access in 42% of patients.

Following SBRT with a planned target volume of 42.6 ± 22.8 ml, the immediate effect was not observed in any patient, VT burden gradually decreased over weeks or months.

Seventeen (52%) patients died (2 of them suddenly) during the mean follow up of 29 ± 23 months mainly due to the progression of heart failure (Figure 1). One patient died due to bleeding associated with esophagopericardial fistula that developed 9 months after SBRT.

Overall, the number of DC shocks after a single procedure decreased significantly from 0.9 ± 1.9 per month in the period of 6 months before SBRT to 0.1 ± 0.3 per month in the period of 6-12 months after SBRT (P=0.008, Figure 2). However, 14 patients (42%) had to undergo additional CA due to VT recurrences at a mean interval of 13 ± 14 months after SBRT. Three patients underwent repeated SBRT (after 3, 29, and 38 months), which was successful in 2 of them.

Conclusions

SBRT in patients with refractory VT is feasible but the long-term mortality after the procedure is high and reflects mainly the severity of the underlying disease. The treatment effect of SBRT is delayed and additional CA is often necessary for VT suppression. At present, SBRT should be offered as only a bailout procedure for otherwise intractable VT.

Novel multi-site, multi-point biventricular pacing configuration: acute haemodynamic benefit

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by the research grant of the AZV (Ministry of Health of the Czech Republic)

Background

Biventricular pacing (BVP) using multiple left ventricular (LV) sites may augment the hemodynamic effect of cardiac resynchronisation therapy (CRT) by engaging a greater mass of the myocardium.

Purpose

To evaluate the acute hemodynamic effect of a novel multi-site, multi-point BVP configuration.

Methods

The study investigated 18 patients with idiopathic dilated cardiomyopathy and left bundle-branch block during implantation of a BVP device (age: 59 ± 14 years, female gender: 7 [39%], LVEF: 27 ± 6%, native QRS: 171 ± 16 ms). Conventional leads were placed in the right atrium (RA) and ventricle (RV), one quadripolar LV lead (Quartet, Abbott, Abbott Park, IL, USA) was positioned in the posterolateral and another one in lateral or anterolateral coronary vein. Individual bipoles of all leads were connected through a splitter to separate external cardiac stimulators. Hemodynamics was evaluated using a micromanometer-tipped catheter (Micro-Cath, Millar, Tx, USA) located in the LV during RA pacing above sinus rate and five atrio-ventricular sequential pacing configurations at the same rate: 1.) RA+RV, 2.) RA + RV + distal bipole of the LV lead with greater dP/dT („conventional BVP"), 3.) RA + RV + distal and proximal bipoles of the LV lead with greater dP/dT („single-lead multi-point BVP"), 4.) RA + RV + distal bipoles of both LV leads („two-lead multi-site BVP"), and 5.) sequentional pacing RA + RV + all bipoles of both LV leads interconnected to a mesh („maximum BVP").

Results

Compared to RA pacing, LV dP/dT was significantly greater during all BVP pacing configurations (RA pacing: 1940 ± 507 mmHg/s vs. conventional BVP: 2431 ± 855 mmHg/s, single-lead multi-point BVP: 2539 ± 740 mmHg/s, two-lead multisite BVP: 2517 ± 836 mmHg/s, and "maximum BVP": 2685 ± 893 mmHg/s, all p<0.001, Figure 1), but not during RA-RV pacing (2014 ± 721 mmHg/s, p=0.12). In addition, dP/dT was significantly greater during "maximum BVP" compared to conventional BVP (p=0.05).

Conclusion

Compared to RA pacing and conventional BVP, the greatest increase in LV contractility was achieved with a novel multi-site, multi-point "maximum BVP" configuration. These preliminary findings provide a rationale for designing new approaches to CRT.

Ultrasound-guided femoral venipuncture for catheter ablation of atrial fibrillation: clinical benefit

Funding Acknowledgements

Type of funding sources: None.

Background

The most frequent complications of catheter ablation for atrial fibrillation (AF) are related to vascular access.

Purpose

Vascular complication rates of ultrasound-guided venipuncture (USGV) were analyzed and compared to historical controls (CTRL) with an anatomical landmark-guided approach.

Methods

The study cohort included 4646 consecutive patients (2330 and 2316 patients in USGV and CTRL groups, respectively). Clinical characteristics were as follows: age of 61±10 years, 67% males, 66% paroxysmal AF, CHA2DS2-VASc score of 2.0±1.4, 27% reablation, and procedure time of 208±69 min. Both femoral veins were cannulated with 2 and 2 sheaths (7, 11, and 2x 8.5 French) in the majority (>95%) of procedures. Major complications were defined as those requiring intervention (surgery, thrombin injection, or transfusion), or hematoma/bleeding with hemoglobin drop >30g/l, or condition prolonging hospitalization and/or resulting in re-hospitalization. They were extracted from the institutional tracking system for complications of invasive procedures and by a review of medical reports within the first 3 months of follow-up.

Results

There were 32 (1.38%) vs. 62 (2.66%) major complications related to vascular access in USGV and CTRL groups, respectively (Yates corrected Chi-square P=0.003), i.e. relative reduction of -48% in the USGV group. Surgical intervention was needed in 6 (0.26%) vs. 18 (0.77%) patients, respectively (Fisher exact test P=0.02), i.e. relative reduction of -64% in the USGV group. The differences remained significant after adjustment for baseline clinical characteristics. Multivariate analysis revealed that USGV strategy (P=0.0005), male gender (P=0.003), and less advanced age (P=0.0002) were significantly associated with lower complication rates.

Conclusions

USGV was associated with a statistically significant reduction of major vascular complications after catheter ablation for AF. This strategy also decreased the need for surgical correction of vascular complications. Ultrasound guidance can be recommended to improve the safety of femoral venous access.

Anatomically-guided cardioneuroablation for recurrent neurally mediated syncope

Funding Acknowledgements

Type of funding sources: None.

Background

Cardioneuroablation (CNA) has been proposed as a new therapeutic approach in selected patients with recurrent neurally mediated syncope and documented cardioinhibitory component.

Purpose

We report on procedural data and clinical outcomes of consecutive patients who underwent anatomically-guided CNA at our center in the period of 2014 - 2021.

Methods

A study investigated 145 otherwise healthy patients (age: 40 ± 14 years, 56% males) with recurrent reflex syncope and the physiological result of the atropine test. Biatrial radiofrequency (RF) ablation was performed under general anesthesia by irrigated-tip catheter at empirical sites of ganglionated plexi (GP) with the navigation by CARTO-3 system and intracardiac echocardiography. Anterior right GP and posteromedial left GP were always targeted to modulate the innervation of both sinoatrial (SAN) and atrioventricular (AVN) nodes, irrespective of clinical manifestation of the disease. The loss of responsiveness of both nodes to extracardiac vagus nerve stimulation was the procedural endpoint. Right vagus or bilateral vagus nerve stimulation was used in 86% and 54% of procedures, respectively.

Results

Enrolled patients had documented cardioinhibitory disorder of SAN (59%), AVN (30%), or both nodes (11%). CNA (duration: 157 ± 31 min; RF time: 15 ± 6 min; radiation dose: 84 ± 135 µGy.m²) resulted in sinus rate acceleration by 28 ± 12 bpm, shortening of AH interval by 15 ± 31 ms, an increase of Wenckebach point by 28 ± 33 bpm, shortening of AVN effective refractory period by 110 ± 115 ms, and sinus node recovery time by 508 ± 666 ms. During a median follow up of 26 (IQR: 12-39) months, CNA was repeated in 9 patients and is scheduled in 3 other (total 8%). Pacemaker was implanted only in 4 (3%) patients after single (n = 2) or repeated CNA (n = 2). Corresponding Kaplan-Meier curves are provided in the Figure. Any-syncope-free survival is comparable to that reported in active arms of historical and recent pacemaker studies.

Conclusions

CNA is a reasonably effective treatment option for patients with functional cardioinhibitory syncope. CNA can be performed by anatomically-guided ablation at empirical GP sites. Our study corroborates the clinical utility of CNA as a viable alternative to pacemaker implant in selected patients.

Measurement of electrical dyssynchrony in CRT patients: 12-lead ECG versus 96-lead body surface map

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant agency AZV, Ministry of Health of the Czech Republic

Background

Quantification of electrical dyssynchrony would allow optimization of lead placement and timing in patients with CRT. The standard deviation of activation times (SDAT) derived from body surface maps (BSM) was proposed as a measure of electrical dyssynchrony in CRT patients. However, SDAT derived from standard 12-lead ECG would be clinically preferred.

Objective

To evaluate and compare the SDAT measured from BSM and 12-lead ECG for assessment of electrical resynchronization in patients with implanted CRT.

Methods

CRT patients with sinus rhythm and LBBB at baseline (n=19, 58% males; age 60±11 years; NYHA class II-III; QRS 160±29) were studied using 96-lead BSM. For each ECG lead, the activation time was automatically detected and SDAT was calculated using either 96 leads or standard 12 leads. Electrical dyssynchrony was assessed during native sinus rhythm and 6 different pacing modes (see figure).

Results

SDAT calculated from BSM and 12-lead ECG decreased during optimal BiV pacing as compared to sinus rhythm by 26% (p=0.006) and 30% (p=0.003), respectively. The two other BiV setups showed also a decrease in SDAT values. Importantly, a high degree of reliability was found between values of SDAT obtained from12-lead ECG and 96-lead BSM for different pacing modes, the intraclass correlation coefficient was 0.8 to 0.9 (95% CI 0.7 - 0.9, p<0.001).

Conclusion

SDAT assessment is considered an important metric of electrical dyssynchrony in CRT. Our results suggest that 12-lead ECG provides similar results as BSM and thus, allows simplification of the measurement. Further prospective studies are necessary to verify the clinical utility of SDAT from 12-lead ECG.

Interleukin-6 predicts recovery of systolic function after myocardial infarction

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of the Czech Republic

Background

Interleukin (IL)-6 is an important mediator of the inflammatory response to acute myocardial infarction (MI). Increased IL-6 levels are associated with adverse outcomes after MI. However, there are only limited data on the association of IL-6 levels with recovery of systolic function after MI.

Purpose

The aim of the present study was to evaluate the independent predictive value of IL-6 level for recovery of systolic function among patients hospitalized for their first MI.

Methods

Consecutive patients without previous history of MI or cardiomyopathy with left ventricular ejection fraction (LVEF) ≤40% measured by transthoracic echocardiography upon hospital discharge and available follow-up LVEF evaluated between 3 months and one year since hospital discharge were selected from a prospective registry of MI patients (n=1323).

Results

In total, data from 183 patients (mean age 64.2±11.2, 29% female, mean EF upon discharge 32.6±5.8) were analyzed. In the multivariate linear regression, IL-6 level measured within 24 hours from the hospital admission was positively associated with NT-proBNP, maximal hs-Troponin T a glycemia level and negatively with female gender, total cholesterol and admission systolic blood pressure. During follow-up, LVEF increased by 6.1±9.0% and LVEF recovered to value >50% in 43 (23.5%) patients. In the multivariate analysis, LVEF improvement was predicted by lower IL-6, lower maximal troponin level, female gender, lower heart rate at the time of hospital admission and Killip class I. In the ROC analysis (AUC 0.72, p<0.001), IL-6 ≤ 15.7ng/L had 51% sensitivity and 87% specificity to predict LVEF recovery.

Conclusion

The inflammatory response to MI, as assessed by IL-6, is associated with MI size, glucose and lipid metabolism and is lower in women. IL-6 independently predicts change in LVEF among patients with moderate to severe LV dysfunction. This supports previous findings that IL-6 inhibition can increase myocardial salvage after MI and identifies possible patients that may benefit from targeted therapy.

Effect of complex weight-reducing interventions on rhythm control in obese individuals with atrial fibrillation following catheter ablation (HOBIT-AF)

Funding Acknowledgements

Type of funding sources: None.

Introduction

HOBIT-AF is a single-blinded, parallel-group randomised controlled trial with 18-month follow-up to assess the effect of complex weight-reducing interventions supported by the use of smart technologies on the arrhythmia burden in obese individuals following catheter ablation for atrial fibrillation. Participants in the intervention group will be provided with a smartphone and smartwatch at month 3 visit for the rest of the trial and the participants in the control group at month 9 visit for the rest of the trial. A purpose-made mobile application will be pre-installed on smartphone. This application will enable participants to generate an ECG report twice a day and in case of an arrhythmia episode. Participants will be asked to regularly provide their weight, blood pressure and physical activity, and these data, together with heart rate, ECG trace and steps count will be securely transferred to investigators at the local home-monitoring centre. Besides, a custom-made website was designed for the participants of the trial containing useful tips concerning nutrition, cooking tips and physical activities.

Purpose

The effect of complex weight-reducing interventions on the arrhytmia burden and quality of life.

Methods

One hundred and sixty individuals (age 18–70 years, body mass index ≥ 30 kg/m2) will be randomised in a 1:1 fashion to undergo a structured weight reduction programme aiming to achieve greater than 10% weight reduction from baseline (intervention group) or standard post-ablation medical care (control group).

Results

Until 30th September 2021, 31 people were randomized to the intervention group (5 people resigned) and 34 people to the control group (1 person resigned).

Since the start of the study, patients in the intervention group reduced their body weight by 5% so far, and most of them (73%) still have 9 months of active intervention to go. Participants in the control group gained on weight an avarage of of 1.6% over the reference period (39% of those surveyed in month 9).

Conclusion

This trial will employ smart technologies to increase the motivation and adherence to introduced lifestyle changes.

Mutation in a non-desmosomal gene is associated with poor outcome of endo-epicardial ventricular tachycardia ablation in patients with nonischaemic cardiomyopathy

Background

Nonischaemic cardiomyopathy (NICM) represents a heterogenic disorder with a variable arrhythmogenic substrate. Its location is often epicardial and catheter ablation in this location proved to be an effective therapeutic modality in NICM patients with recurrent ventricular tachycardias (VTs).

Purpose

To determine the impact of the type of genetic mutation on the long-term outcome of endo-epicardial ablation in patients with NICM.

Methods

We investigated 82 patients (age 47±15 years, 10 women) with NICM who underwent endo-epicardial ablation for frequent VTs. Of them, 59% had a history of failed endocardial ablation. Patients had a left ventricular ejection fraction of 44±14% and all were implanted with cardioverter-defibrillator. One hundred candidate genes were examined using the new generation sequencing technique.

Results

Mutation in genes coding desmosomal complex (genes: PKP2, DSC, DSP, and DSG) was found in 30% of patients (“desmosomal” group). In 23% of patients, other gene mutations (genes: LMNA/C, MYH7, DES, TTN, RYR2, TPM1, MYPN, FLNC, and SCN5A) were detected (“non-desmosomal” group). In 46% of subjects no pathogenic mutation could be identified (“none” group). During a mean follow up of 34±33 months, patients in the “non-desmosomal” group were at significantly higher risk of VT recurrence and death/heart transplant compared to patients in the “desmosomal” group (Figure 1).

Conclusion

Potentially pathogenic mutation can be detected in about half of patients with NICM undergoing endo-epicardial VT ablation. Most commonly, mutations can be found in genes coding desmosomal complex and the endo-epicardial ablation is then associated with a satisfactory low VT recurrence rate and excellent survival in the long-term. On the other hand, patients with a mutation in non-desmosomal genes have poor outcomes despite endo-epicardial ablation.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by Ministry of Health of the Czech Republic, grant nr. NV18-02-00237 Figure 1

Temporary prolongation of corrected QT interval after cardioneuroablation for functional bradyarrhythmias

Background

There are controversial reports on QT interval response to ganglionic plexi ablation that are selectively targeted during cardioneuroablation (CNA) or occurs as collateral lesion during left atrial ablation procedures. Both shortening or prolongation of the heart-rate corrected QT interval (QTc) with therapeutic or safety implications were described.

Purpose

In this retrospective study, we investigated longitudinal changes of QTc after CNA.

Methods

The study included 108 patients (age: 39±12 years, 60% males) who underwent biatrial cardioneuroablation (radiofrequency time: 15.5±6.7 min) for symptomatic functional bradyarrhythmias. Surface ECG examinations were performed on the day before the CNA (N=108), 1 hour after the CNA (N=106), on the 1st post-ablation day (N=50), at the 3-month (N=99), and 1-year (N=63) follow-up visits. Automated measurements of QT interval were employed for the analysis. Four formulas (Bazett, Framingham, Fridericia, and Hodges) were used for the correction of QT interval to instant heart rate.

Results

QTc significantly prolonged immediately after the CNA with rapid return to baseline values (Figure and Table). This was particularly valid for QT correction by Framingham formula (and similarly for Fridericia and Hodges formulas). The QTc by Bazett formula, which is known to overestimate QT at higher heart rates, returned to baseline more slowly and incompletely. Several mechanisms may contribute to observed QTc dynamics: (1) direct effect of autonomic denervation with recovery phenomenon; (2) QT hysteresis with an extremely long time constant; or (3) artifact due to suboptimum QT correction to a substantial change of heart rate.

Conclusions

The study suggests that CNA produces acute prolongation of QTc interval with rapid decay and virtual normalization in 3 months. CNA in otherwise healthy subjects is not likely associated with substantial long-term risk of long-QT-associated arrhythmias. In the same way, we cannot confirm earlier observations of clinically significant QTc shortening effect of ganglionated plexi ablation.

Funding Acknowledgement

Type of funding sources: None. Figure 1Table 1

Acute change in parasympathetic cardiac innervation after pulmonary vein isolation by pulse-field and radiofrequency energy

Background

In patients with atrial fibrillation (AF), pulmonary vein isolation (PVI) by radiofrequency (RF) energy is associated with a significant change of cardiac autonomic regulations due to collateral ganglionic plexi ablation. Pulse-field (PF) ablation energy presumably spares neural tissue.

Purpose

We compared the effect of PVI by PF and RF energy on cardiac autonomic function.

Methods

A study enrolled 23 patients who underwent PVI in general anaesthesia. In 12 patients, a novel lattice-tip catheter and PF energy were used for ablation while 11 patients were ablated using a conventional irrigated-tip catheter and RF energy. The response of the sinus node (SAN) and atrioventricular node (AVN) to extracardiac high-frequency vagal stimulation (ECVS) was tested before and after PVI (via right internal jugular vein; stimulation frequency of 50 Hz; pulse width of 0.05 ms; output of 1 V/kg (<70V); train duration of 5 s).

Results

At baseline, physiological massive response to ECVS (sinus arrest and/or AV block) was demonstrated in the majority of patients. After PVI, complete loss of autonomic response of the SAN in 11/11 (100%) and 3/12 (25%) patients (p=0.003), and the AVN in 9/11 (82%) and 3/12 (25%) patients (p=0.01) was observed in RF and PF groups, respectively. The figure shows the maximum duration of the pause in sinus rhythm (maximum P-P interval) and AVN block (maximum R-R interval during atrial pacing) induced by ECVS after PVI.

Conclusion

Cardiac vagal response is preserved in a considerable proportion of AF patients after PF ablation which is in contrast with a significantly stronger effect of RF energy. This may influence the clinical outcome of AF ablation procedures.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Institute for Clinical and Experimental Medicine, Prague

Anatomical variants of the cavotricuspid isthmus in patients undergoing catheter ablation for atrial flutter and/or atrial fibrillation

Background

We evaluated the differences in the anatomy of the cavotricuspid isthmus (CTI) by assessing image loops provided by intracardiac echocardiography (ICE) in patients who underwent ablation for atrial flutter and/or atrial fibrillation.

Purpose

CTI is an essential component of the reentrant circle in isthmus–dependent atrial flutter (CTI-AFL) and a target for catheter ablation. In some patients, CTI anatomy may be responsible for a difficult procedure. The aim of this study is to describe in details the anatomical variants of this structure.

Methods

We included a group of 138 patients, who underwent cardiac ablation for atrial flutter and/or atrial fibrillation between August 2020 and January 2021. Intracardiac echocardiography was employed during the intervention to evaluate the morphology of CTI. Analysis was focused on size, shape, presence of sub-eustachian pouch (excavation more than 5 mm) or presence of prominent Eustachian ridge (ER, embryologic remnant of the valve of the IVC) and mobility of the structure.

Results

The length of CTI measured during ventricular systole averaged at 38,4mm (min 22,5mm, max 60mm). The most frequent pattern was a flat CTI without sub-eustachian excavation or with excavation less than 5mm (71 patients; 51.4%). A pouch (excavation more than 5mm) was observed in 41 pts (29.7%), where the deepest pouch reached 10,5mm. Prominent ER was present in 58 pts (42%). The remaining 26 of CTIs (18.8%) were classified in the “unclassifiable” category with deviations from common anatomic variants - substantial convexity, pronounced trabeculation of isthmus or double pouch. We observed 14 CTIs (10.1%), where the structure was partially or in full extent detached from the diaphragm, sliding during cardiac contractions. In addition to the described morphology, Chiari's network was observed in 18 pts (13%).

In reference to mobility, 53 pts (38.4%) presented with hypermobile CTI with a difference in size of more than 1/3 between the diastole and systole.

Moreover, we looked into differences of CTI related to BMI, left atrial volume index (LAVi) and ejection fraction of the left ventricle. A positive correlation was found between LVEF and mobility of CTI. Hypermobile CTI was present in 42.2% of pts with normal LVEF compared to only 18.9% of pts with reduced EF (EF less than 50%). Similar results were observed in pts with non-dilated LA, where hypermobile CTI was present in 51.9% of pts compared to only 35.1% of pts with dilated LA with LAVi >28 ml/m2 (see table below).

Conclusions

We observed a substantial differences in the anatomy of the CTI, which could play an important role in catheter ablation of this structure. Besides the prominent ER, significant sub-eustachian pouch and hypermobility appear to be variants predisposing to difficult ablation.

Funding Acknowledgement

Type of funding sources: None. CTI variants related to EFLV, BMI, LAViCTI detached from the diaphragm

Radiofrequency catheter denervation of sinus node: a randomized comparison of right and left atrial approach for the cardioneuroablation

Funding Acknowledgements

Type of funding sources: None.

Background

Radiofrequency catheter ablation of superior paraseptal ganglionic plexus is an important step to eliminate the vagal modulation of sinus node for the treatment of neurally-mediated syncope. The reasonable effect can be achieved by targeting this plexus from the endocardial aspect of both right (RA) and left (LA) atria.

Purpose

We investigated the efficacy of RA and LA ablation in terms of sinus nodal denervation.

Methods

The study included 24 patients (age: 42 ± 13 years, 50% males) who underwent cardioneuroablation for recurrent cardioinhibitory syncope in general anesthesia. Right atrial semicircular lesion at the posteroseptal quadrant of superior vena cava ostium was composed of 5-6 equidistantly distributed ablation sites (30 W, 30 s, 20 ml/min).  Left atrial lesion of comparable size was placed strictly contralaterally across the interatrial septum in the anterior vestibulum of a right superior pulmonary vein. Patients were randomly (1:1) assigned to RA-to-LA or LA-to-RA ablation. Sinus rate and the response to extracardiac right vagal nerve high-frequency stimulation (50 Hz, 0.05 ms, 1 V/kg [<70V], 5 s) were recorded at baseline and after each ablation cluster.

Results

Study protocol ablations overall resulted in sinus acceleration (81 ± 13 vs. 59 ± 12 bpm, P <0.0001) and attenuation of inducible sinus arrests (maximum pause: 1.2 ± 1.4 vs. 5.5 ± 3.0 s, P <0.0001). Temporal development of outcome measures with the progression of ablation is shown in the Figure. There was no significant difference between study groups. Irrespective of ablation order, the first ablation cluster on average generated 77% of the final effect on sinus rate and 68% of the final effect on suppression of vagally-induced sinus pauses.  

Conclusions

 Neither RA nor LA approach is preferable for targeting the superior paraseptal ganglionic plexus. Both ablation clusters convey complementary and, in part, mutually independent effects. Biatrial cardioneuroablation seems essential for efficacious sinus nodal denervation. Abstract Figure.

Effects of pulse field and radiofrequency pulmonary vein isolation on parasympathetic cardiac innervation

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): IKEM

Background

Pulmonary vein isolation (PVI) is an established treatment modality for patients with atrial fibrillation (AF). PVI performed by radiofrequency (RF) energy results in parasympathetic denervation of the heart by collateral ganglionic plexi ablation. Pulse field (PF) is a novel nonthermal energy source for PVI that selectively ablates atrial myocardium while preserving cardiac autonomic nerves, which may affect the outcome after PVI.

Purpose

The study compared the effect of PVI between RF and PF ablation on cardiac autonomic function and a short-term AF recurrence rate. The resting heart rate (HR) was evaluated as a simple index of sinus nodal parasympathetic innervation.

Methods

We investigated 45 patients (aged 64 ± 7 years, 4 women) who underwent PVI by novel three-dimensional electroanatomical mapping/ablation system (lattice electrode ablation system). PVI was performed by either high-energy RF (n = 21) or PF (n = 24) energy using the identical ablation catheter. Resting HR assessed by standard ECG was recorded the day before the procedure and at the 3-month visit. Arrhythmia recurrences were analysed by 24-Holter at the 3-month visit.

Results

All PVs were acutely isolated in all patients. The HR data are shown in the Table. The baseline HR did not differ between both groups. A significant increase in HR was observed only in the RF ablation subgroup. The between-group difference remained significant even after adjustment for age, gender, and baseline HR. There was no difference in arrhythmia recurrences at the 3-month visit between study groups.

Conclusions

  Parasympathetic denervation effects on HR after the PF ablation are virtually absent. Comparable AF recurrence rate at 3-month visit after RF and PF ablation suggests that preservation of autonomic innervation has no impact on AF recurrence during short-term follow-up. Table RF PVI (n = 21) PF PVI (n = 24) P Baseline HR (bpm) 60.0 ± 7.1 63.8 ± 9.4 n.s. HR change - 3-month visit (bpm) 14.4 ± 6.9 0.3 ± 8.6 P <0.001 Arrhythmia recurrences 3/21 (14%) 2/24 (8%) n.s.

Accuracy of electroanatomical mapping guided cardiac radiotherapy for ventricular arrhytmias: pitfalls and solutions

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was partially supported by the grant AZV NU20-02-00244 from the Ministry of Health of the Czech Republic

OnBehalf

WECAM

Background

One of the main limitations of Radiofrequency catheter ablation (RFCA) is the difficulty in targeting specific VT substrate locations when they are deep intramural, covered by epicardial fat or in the proximity of a coronary artery. Stereotactic body radiotherapy (SBRT) has emerged as an alternative treatment for VT after RFCA failure. However, the accuracy of substrate volume delineation, the gross target volume (GTV), based on electroanatomical mapping (EAM) and interobserver agreement are still unknown.

Aim

To analyze and optimize the interobserver agreement for GTV delineation on cardiac CT (CCT) based on EAM data acquired to guide radiotherapy for ventricular arrhythmias.

Method

Available EAM data was exported and merged with the segmented CCT using manual registration by two observers. A GTV was created by the observers for predefined left ventricular (LV) areas based on preselected endocardial EAM points, indicating the 2D-surface area of interest. The interobserver (non)overlapping GTV volumes were analyzed. The influence of (interobserver) registration accuracy and availability of EAM data on the final GTV and 2D-surface location within each LV area was evaluated.

Results

The median distance between the CCT and EAM after registration was 2.7 mm, 95%th percentile 6.2 mm for observer #1 and 3.0 mm, 95%th percentile 7.6 mm for observer #2 (p = 0.9). Created GTVs were significantly different (8 vs 19 ml) with lowest GTV overlap (35%) for lateral wall target areas. Similar, the highest shift between 2D-surfaces was observed for the lateral LV (6.4mm (3.0-9.9)). The same trend is seen in the (non) overlapping volume for lateral area (P = 0.004). The optimal surface registration accuracy (2.6 mm) and interobserver agreement (Δ interobserver EAM surface registration accuracy 1.32 mm) on final GTVs could be achieved if at least three cardiac chambers were mapped, including high-density LV EAM.

Conclusion

Detailed EAM of at least three chambers allows for accurate co-registration of EAM data with CCT and high interobserver agreement on GTVs to guide radiotherapy of ventricular arrythmias. However, the substrate location should be taken in consideration when creating a treatment volume margin. Gross target volume (GTV) and InterobserGTV volume Observer #1 (cc)GTV volume Observer #2 (cc)Surface shift (mm)Basal anterior, (IQR)7.6 (6.2-11.5)9.3 (5.3-10)3.8 (2.2-4.5)Lateral, (IQR)8.0 (6.9-12.7)19.1 (15.7-21.4)6.2 (5.3-6.4)Septal, (IQR)10.1 (6.2-12.8)13.9 (7.7-14.6)6.4 (3.0-9.9)Abstract Figure. Graphical abstract

Outcomes of post mortem genetic diagnosis in SCD victims and primary prevention of cardiac arrest in relatives: a nationwide multidisciplinary and multicentric collaboration in the Czechia

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Supported by Ministry of Health of the Czech Republic

Introduction

Post mortem genetic analysis in sudden cardiac death (SCD) represents an important diagnostic tool for the primary prevention of cardiac arrest in victim´s relatives. 

Purpose

To assess the underlying molecular pathogenesis of SCD in a representative Czech cohort and to evaluate the effects of primary prevention of SCD in genetic relatives. 

Patients and Methods

Between 2016 and 2020 we have ascertained 100 SCD cases (29 females/71 males; age range 0-52 years). According to autopsy protocols, cases with SCD were divided into categories of sudden arrhythmic death (SADS), sudden unexplained death (in infants; SUD/SUDI), thoracic aortic aneurysm/dissection and cardiomyopathy hypertrophic, arrhythmic, dilated (HCM, ACM, DCM) and sudden infant death syndrome (SIDS). DNA was isolated from post mortem biopsies / relatives blood and subjected to massively parallel sequencing (Illumina, USA) comprising custom-made candidate gene panel (100 genes). Genetic counselling and cardiological examinations were carried out in 245 family members. 

Results

According to post mortem-established diagnosis, we identified 20 victims with SADS and SUD/SUDI, 11 with HCM and DCM, 19 with ACMG, 8 SIDS cases and 9 acute dissection cases. Most of victims died at sleep or at rest, while only 10/100 victims died during strenuous sport activities. About 50% of SCD victims did not report any apparent cardiac complaints. Highly likely or certain molecular etiology (i.e. based on presence of ACMG.net Class 4 to 5 variants) was disclosed in 19/100 (19%) in RYR2, KCNH2, SCN5A, FLNC (stop), TTN, RBM 20, LMNA/C, PRKAG2, MYBPC3, DSC2, FHL1, TGFBR1 and Col3A1 genes (see Tab). Finally, we identified 52/241 phenotype/genotype positive family members who are at risk of cardiac arrest and were offered  corresponding cardiological care.

Conclusion

Multidisciplinary cooperation, together with centralized and standardized molecular genetic testing, enables the primary prevention of cardiac arrest in relatives of SCD victims.

Results of post mortem genetic analysis Post mortem diagnosis Nr. Gender Age (years) Nr. of positive cases (DNA variant class IV or V) Gene Nr. examined relatives/phenotype or genotype positive cases SADS 20 8 females12 males 3-52 5/20 (25%) KCNH2 3x RYR2RANGFR 56/11 SUD/SUDI 20 5 females, 15 males 0-50 1/18 (5%, 2 non informative cases) RYR2 45/9 HCM 11 0 females11 males 14-52 3/11 (27%) MYBPC3FHL1PRKAG2 26/9 DCM 11 3 females8 males 8-48 4/11 (36%) TTN (3x)RBM 20FLNC (stop) 24/7 ACM 19 9 females10 males 17 - 49 4/19 (21%) SCN5AFLNC (stop)DSC2LMNA/C 58/9 SIDS 8 3 females5 males < 1 0/8 - 12/0 Acute dissection 9 1 female8 males 16-49 2/9 (22%) TGFBR1Col3A1 24/7

[Unstable RAMP Lesions of the Medial Meniscus in ACL-Deficient Knee: Comparing the Outcomes of Outside-in versus All-inside Surgical Repair - a Retrospective Study]

PURPOSE OF THE STUDY We present the results of the retrospective study comparing the clinical outcomes of outside-in versus all-inside suture techniques of unstable RAMP lesions (RL) of the medial meniscus in patients with simultaneous ACL lesion with a minimum two-year follow-up. MATERIAL AND METHODS The retrospective evaluation covered two groups of patients who underwent the arthroscopic repair of unstable RL in combination with anterior cruciate ligament reconstruction (ACLR). Group 1 included 42 patients (28 men/24 women). Group 2 consisted of 36 patients (21 men/15 women). In Group 1, RL suture repair using the outside-in technique by posteromedial approach with absorbable PDS suture was performed, while in Group 2 the all-inside technique of RL suture via the standard anteromedial portal was applied using the Fast-Fix system (Smith Nephew, USA). The evaluation was done preoperatively and postoperatively with the mean follow-up of 27.9 months in Group 1 and 30.1 months in Group 2. The patients were assessed using the subjective IKDC score and the side-to-side difference (SSD) in ventral laxity was measured by Genourob (GNRB) laximeter at the applied pressure of 134 N and 250 N. Moreover, the failure rate of RAMP lesion repair, ACL graft, necessity of secondary partial meniscectomy and return to pre-injury level of sport were analysed. RESULTS The median IKDC score increased in Group 1 from 56 points preoperatively to 92 points postoperatively and in Group 2 from 58 points preoperatively to 90 points postoperatively (p>0.05). The median value of SSD in ventral laxity of the knee measured by the GNRB laximeter at the applied pressure of 134 N in Group 1 was 5.6 mm preoperatively and 1.9 mm postoperatively and in Group 2 it was 5.9 mm preoperatively and 2.3 mm postoperatively. At the pressure of 250 N, the median value in Group 1 was 7.9 mm preoperatively and 2.7 mm postoperatively and in Group 2 it was 8.1 mm preoperatively and 3.2 mm postoperatively. When comparing the SSD of the groups postoperatively, no statistically significant difference was found (p>0.05). Revision arthroscopy was performed in 8 patients. In 1 patient (2.4 %) in Group 1 and in 4 patients (11.1%) in Group 2 a rerupture of the RL of the meniscus occurred and partial meniscectomy was performed. In Group 2, statistically significant higher occurrence of the RL suture failure (p<0.05) was reported and there was a need to perform partial medial meniscectomy (p<0.05). The ACL graft failure was observed in 2 patients (4.7%) in Group 1 and in 3 patients (8.3%) in Group 2 (p>0.05). 31 evaluated patients (73.8%) from Group 1 and 24 patients (66.7%) from Group 2 (p>0.05) returned to the pre-injury level of sports activities. DISCUSSION When comparing the outcomes of individual techniques of the RL repair published in recent literature with our conclusions, we may state that the results of subjective as well as objective criteria achieved were similar to those reported by other authors worldwide. No study has so far been published which would compare the outcomes of the by us presented two surgical techniques of the RL suture in an ACL-deficient knee with a minimum follow-up of 24 months. CONCLUSIONS Both the surgical techniques of unstable RL repair in combination with the ACLR using a tendon graft result in a statistically significant improvement of clinical outcomes postoperatively. In Group 2, with the all-inside RL repair, a statistically significant higher failure rate of RL repair was confirmed as well as the need to perform secondary partial meniscectomy compared to Group 1. Key words: RAMP lesion, ACL-deficient knee, unstable medial meniscus lesion, repair of meniscus, all-inside technique, posteromedial technique, ACL reconstruction.

[Benefits of the Acetabular Microfracture Technique in Arthroscopic Treatment of Chondral Defects in Femoroacetabular Impingement Syndrome: Two-Year Results of a Multicenter Prospective Randomized Study]

PURPOSE OF THE STUDY Two-year clinical results of a multicenter prospective randomized study in patients with arthroscopically treated Femoro - acetabular Impingement syndrome and concurrently performed microfracture for grade IV chondral lesions of the acetabulum. MATERIAL AND METHODS The study evaluated a group of 55 patients of the originally enrolled 92 patients with the underlying diagnosis of FAI syndrome with intraoperatively confirmed grade IV acetabular chondropathy of up to 4 cm2 in size, who had undergone a comprehensive hip arthroscopy (correction of structural cam-type and/or pincer-type deformity, labral refixation or partial labral resection etc.) performed by two experienced surgeons. The patients were randomized intraoperatively using a closed envelope method into two groups. In Group 1 (31 patients), microfractures for chondral defects was performed, while in Group 2 the patients underwent a defect debridement procedure only. The studied group included a total of 7 professional and 48 recreational athletes (33 men and 22 women), with the mean age of 34.4 in Group 1 and 31.1 in Group 2. Preoperatively and 6, 12 and 24 months postoperatively the modified Harris Hip Score (mHHS) parameters and VAS score were evaluated and also revision surgeries, conversion to endoprosthesis, and occurrence of complications were recorded. RESULTS Preoperatively, no statistical difference between the two groups was found in the studied parameters (mHHS and VAS). Postoperatively (after 6, 12 and 24 months), in both groups a statistically significant increase in mHHS and VAS score was reported. When comparing the mHHS parameter at individual evaluated times in Group 1 and Group 2, a statistically significant difference was confirmed at 12 and 24 months after surgery (P < 0.001), namely in favour of Group 1. At 6 months postoperatively, no statistically significant difference in this parameter between the two groups was confirmed (P = 0.068). When comparing the VAS score parameter in these two groups at individual times, no statistically significant difference was confirmed at 6 and 12 months after surgery (P= 0.83 / P= 0.39). A statistically significant difference in the VAS score parameter was observed only at 24 months after surgery, namely in favour of Group 1 (P< 0.037). In the course of the follow-up period, altogether 3 patients (2 patients from Group 1) were indicated for revision hip arthroscopy and in 1 female patient an endoprosthesis was implanted. No severe intraoperative or postoperative complications were observed. DISCUSSION In agreement with other authors worldwide, the arthroscopic treatment of FAI syndrome, if indicated and performed correctly, was confirmed to improve the clinical condition of patients postoperatively, regardless of the technique used in treating the chondral defect. Based on our results as well as conclusions of other world authors, in treating the grade IV defects of smaller size it is appropriate, in treating the cartilage, to prefer the microfracture surgery, which is less demanding both technically and financially and contrary to mere debridement allows to fill the original defect by fibrocartilage tissue. CONCLUSIONS The benefits of the acetabular microfracture in patients with the FAI syndrome treated arthroscopically were confirmed. A statistically significant difference between the two studied groups was reported in the mHHS parameter at 12 and 24 months after surgery and also in the VAS parameter at 24 months in favour of the group with performed microfracture. In both the studied groups, the arthroscopy resulted in a statistically significant improvement of the assessed quality of life parameters. Key words: hip arthroscopy, femoroacetabular impingement syndrome, chondral defect, microfracture, abrasive chondroplasty.

Randomized investigation of the left atrial sweet spot for vagal denervation of atrioventricular node during the cardioneuroablation

Background

Radiofrequency catheter ablation of inferior atrial ganglionic plexi frequently results in vagal denervation of the atrioventricular (AV) node. The effective sites are, however, considerably variable.

Purpose

We prospectively sought the left atrial (LA) ablation site with the maximum effect on AV nodal modulation.

Methods

The study included 16 patients (age: 46±14 years, 56% males) who underwent cardioneuroablation for recurrent reflex cardioinhibitory syncope in general anesthesia. After targeting the superior paraseptal ganglionic plexi and achieving the denervation of the sinus node, study ablations were performed at the bottom of the LA to accomplish the AV nodal denervation (Figure). Five equidistantly distributed ablation lesions (30W / 30s / 20ml/min) were created on the virtual line connecting inferior ostium of right inferior pulmonary vein (RIPV) and inferior mitral annulus (MA). Lesions were centered symmetrically relative to the posterior mid-left-atrial line. They were numbered in ascending order from #1 (more septal, closer to the RIPV) to #5 (more lateral, closer to the MA). Patients were randomly (1:1) assigned to mutually opposite direction of ablation (from site #1 to #5 or from site #5 to #1). The response of heart rhythm to extracardiac vagal nerve high-frequency stimulation (50Hz/0.05ms/1V/kg [&lt;70V]/5s) were recorded at baseline and after each radiofrequency energy delivery.

Results

Study protocol ablations overall resulted in elimination or attenuation of inducible AV block (maximum R-R interval: 2.9±2.8 vs. 5.2±2.4s, P&lt;0.001). Temporal development of effect with the progression of ablation is shown in the Figure indicating that the most lateral lesion alone produces the maximum effect. The AV nodal denervation was incomplete after per-protocol ablations in 7/16 patients. In the majority of them, the final success was achieved by extension of ablation lesion toward the inferior mitral annulus either endocardially or via the proximal coronary sinus.

Conclusion

Ablation of perimitral region of the inferior LA conveyed the maximum effect in terms of AV nodal denervation.

Funding Acknowledgement

Type of funding source: None

Comparison of variant detection rate in genes between two cohorts of Czech living patients versus victims of sudden cardiac death with clinical / post mortem diagnosis of non-ischemic cardiomyopathy

Introduction

Hereditary cardiomyopathy is associated with an increased risk of ventricular arrhythmia and sudden cardiac death (SCD). Genetic stratification substantiates risk assessment and enables the primary prevention of SCD in relatives at risk. We have analyzed the genetic aetiology of SCD in a representative Czech cohort with post mortem diagnosis of various forms of cardiomyopathy and compared it to living cases with these cardiac disorders.

Patients and methods

Between 2018 and 2019, altogether 47 victims of SCD with post mortem diagnosis of hypertrophic- (HCM; 18/47), arrhythmogenic- (ACM; 19/47) and dilated cardiomyopathy (DCM; 10/47) were identified. Concurrently, genetic testing was performed in 114 living patients (HCM 54/114, ACM 22/114, DCM 38/114). Genetic counselling and cardiologic examination had been carried out in first-degree relatives in all patients/SCD victims. Massively parallel sequencing (MiSeq platform; Illumina.com) was utilized for a custom-made panel comprising 100 candidate genes (Sophia Genetics, Switzerland). The presence of pathogenic variants was validated by Sanger DNA sequencing and through family segregation analyses.

Results

The causative detection rate (according to ACMG.net classes 4 or 5) in SCD victims with DCM was 60% (6/10) and in living patients with DCM 47.4% (18/38). Variants in TTN, RBM20, DES and FLNC (mainly truncating variants) prevailed in both groups. The detection rate in ACM was 5% (1/19 in SCN5A gene) in SCD victims and 31.8% (7/22) in living patients. Interestingly, the most prevalent mutated gene PKP2 in living patients was not detected in SCD victims. The detection rate in SCD victims with post mortem diagnosis of HCM was 16% (3/18) and in living patients 35% (19/54). The most prevalent gene was MYBPC3 in both groups, while PRKAG2 was detected in one SCD victim and in one living case who survived cardiac arrest.

Conclusion

Post-mortem genetic analysis in DCM yields a high detection rate and allows potentially effective primary prevention of SCD in relatives at risk. In contrast, the molecular autopsy of HCM and ACM renders a much lower yield which is below the mutation detection rate in living phenotype positive individuals. The results help to improve the genetic counselling in affected families in Czech Republic.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of the Czech Republic

Gender-specific risk of complications in catheter ablation for atrial fibrillation

Background

Catheter ablation is an established treatment modality for atrial fibrillation (AF). The risk of procedural complications is not negligible. Some studies suggested that female patients have a higher risk of complications.

Purpose

To identify gender-specific predictors of major complications (MCs) in patients undergoing catheter ablation for AF in a tertiary ablation centre.

Methods

A total of 4733 catheter ablations for AF (65% paroxysmal, 26% repeated procedures) were performed at our centre between January 2006 and August 2018. Patients (71% males) aged 60±10 years and had body mass index of 29±4 kg/m2 at the time of the procedure. Radiofrequency point-by-point ablation was employed in 96.3% procedures with the use of 3D navigation systems and facilitated by intracardiac echocardiography. Pulmonary vein isolation was mandatory; cavotricuspid isthmus and left atrial substrate ablation were performed in 22% and 38% procedures, respectively. MCs were defined as those that resulted in permanent injury, required intervention or prolonged hospitalization. Variables were assessed by uni- and multivariate analysis, two-sided α&lt;0.05 was considered significant.

Results

A total of 160 (3.4%) MCs were detected - 60 (4.4%) in females and 100 (2.9%) in males (P=0.012). Both lower body height and the presence of bundle branch block (BBB) were associated with MCs only in females; for left bundle branch block (LBBB), the effect size was higher. On the contrary, higher left ventricular end-diastolic diameter (LVEDd) and persistent AF were associated with MCs in males (Table).

Conclusion

Females have a higher risk of MCs during catheter ablation for AF. Body height, AF type, BBB, and LVEDd may belong among gender-specific risk factors for MCs in AF ablation procedures. Whether BBB and LVEDd represent true risk factors warrants a validation in further studies.

Funding Acknowledgement

Type of funding source: None

Impact of procedural volume on complication and recurrence rate after atrial fibrillation ablation in European centers. An ESC EORP Registry: Atrial Fibrillation Long-Term

Background

Catheter ablation has emerged as an effective therapy in patients with atrial fibrillation (AF). Despite high success rates of the method, there is still heterogeneity of outcomes and complications across Europe. A center's volume of AF ablations performed per year might also play an important role in the success rate of the procedure as compared to other confounding factors which may be different among centers (such as type of AF ablated, patient selection criteria, referral bias and/or ablation strategy).

Purpose

Aim of the study was to investigate differences in clinical outcomes and complication rates among European AF ablation centers related to the volume of ablations performed annually.

Methods

Data for this analysis were extracted from the European AF Ablation Long-Term Study, a prospective registry designed to describe the clinical epidemiology of patients undergoing AF ablation. Based on 33th and 67th percentiles of number of AF ablations performed, the participating centers were classified into high volume (HV) (≥180 procedures/year), medium volume (MV) (&lt;180 and ≥74/year) and low volume (LV) (&lt;74/year). One-year success was defined as patient survival free from any atrial arrhythmia, from the end of the 3-month blanking period to 12 months following the ablation procedure.

Results

A total of 91 centers in 26 European countries enrolled 3368 patients. There was a significantly higher reporting of cardiovascular complications in LV centers (5.2%), especially pericarditis and cardiac perforation, while the HV and MV centers reported cardiovascular complications in 3.0 and 4.3% of cases, respectively (p=0.039). Additionally, stroke incidence after ablation was significantly higher in LV centers (0.5% of cases vs 0% in HV and MV centers, p=0.008). One-year success after AF ablation ranged from 77.8% in HV vs 70.5% in LV vs 77.3% in MV centers (p&lt;0.001). Despite these unadjusted differences, Kaplan-Meier survival analysis based on adjusted data demonstrated, however, that there were not significant differences in complication and recurrence rates according to volume's center (p=0.328 and p=0.476 accordingly, Figure A). This result was mainly driven by a proportional increase in severity/risk of cases ablated (as evidenced by CHA2DS2-VASc score and AF type) in relation to a center's procedural volume (Figure B).

Conclusions

Low volume centers present slightly higher cardiovascular complications' and stroke incidence and a lower unadjusted success rate after AF ablation. On the other hand, adjusted overall complication and recurrence rates are non-significantly different among different volume centers, a fact reflecting inhomogeneity of patient and procedural profiles and a counterbalance between expertise and risk level among participating centers.

Funding Acknowledgement

Type of funding source: None

P1097Heart rate acceleration is a poor surrogate of complete parasympathetic denervation of sinus node during cardioneuroablation

Background

Ablation of superior paraseptal ganglionic plexi is invariantly associated with the acceleration of sinus rhythm. This is considered a favourable sign during cardioneuroablation for the treatment of recurrent neurally-mediated cardioinhibitory syncope or symptomatic sinus bradycardia.

Purpose

In this retrospective study, we investigated whether the magnitude of sinus rhythm acceleration corresponds with directly assessed sinus nodal parasympathetic denervation.

Methods

The study included 48 patients (age: 39 ± 13 years, 58% males) who underwent cardioneuroablation in general anaesthesia. The procedural endpoint was non-responsiveness (i.e. loss of original cardioinhibitory response) of the sinus node to extracardiac high-frequency stimulation of the vagal nerve. The magnitude of sinus rhythm acceleration was compared between patients who reached or did not reach this endpoint.

Results

All patients had positive atropine test (baseline heart rate: 65 ± 14 bpm; post-atropine: 109 ± 22 bpm). Complete sinus nodal denervation as assessed by vagal nerve stimulation was achieved in 44/48 (92%) patients. Intraprocedurally, heart rate accelerated from 54 ± 11 to 85 ± 14 bpm (difference: 31 ± 10; median 29; interquartile range: 24–40; total range: 13–61 bpm). This change did not correlate with age and was not related to pre-procedural post-atropine sinus rhythm acceleration. There was no difference in heart rate acceleration between the patient with and without sinus nodal denervation (Figure).

Conclusions

Sinus rhythm acceleration is not reliable endpoint for cardioneuroablation. Guidance by extracardiac vagal nerve stimulation may help to tailor the procedures to increase the clinical success rate and, at the same time, to avoid patient overtreatment.

Abstract Figure.

P1107First results of molecular autopsy examinations in sudden cardiac death drawn from nationwide multidisciplinary and multicentric collaboration in the Czech Republic

Funding Acknowledgements

Supported by Ministry of Health of the Czech Republic, grant nr. NV18-02-00237. All rights reserved."

Introduction

"Molecular autopsy" in sudden cardiac death (SCD) is an important diagnostic tool for primary prevention of cardiac arrest in victim´s relatives and requires multicentric and multidisciplinary collaboration.

Purpose

To establish a national network for SCD diagnostics, to assess the acceptance of genetic testing in at risk relatives and to elucidate the genetic etiology of SCD in a representative Czech cohort aged below 45 years.

Patients and Methods

Between 2016 and 2019 we ascertained 70 SCD (50 M / 20 F), with positive family history for cardiac arrest in 8/70 cases. Only one family did not agree with molecular autopsy. Genetic counselling and cardiological screening examination was carried out in first degree relatives of SCD survivors accompanied by custom-made targeted panel massively parallel DNA sequencing comprising 100 cardiac conditions-related genes. Presence of pathogenic variants was validated by Sanger DNA sequencing and through family segregation analyses.

Results

According to post-mortem diagnosis most victims died of HCM (17/70), ACM (16/70), no structural heart disease was found in 15/70 cases, DCM/LVNC in 9/70, 6/70 were SIDS cases, other rare diagnoses comprised aortic dissection, or myocarditis. Most of victims died at sleep, only 9/70 victims died during strenuous activities. About 50% of SCD victims did not have cardiac complaints before death. Very likely or certain molecular etiology (i.e. based on presence of ACMG.net Class 4 to 5 variants) was disclosed in 12/70 (17%) in RYR2, FLNC, TTN, KCNH2 and KCNQ1 genes, whilst potentially causative DNA variants (Classes 3-4) were observed in 13/70 (18%) cases. In SIDS we did not find any pathogenic variants. Interestingly, the KCNE1 p.Asp85Asn (LQT 5 lite) variant, was detected in 3/70 cases as a recognized risk factor for ventricular arrhythmias.

Conclusion

The multidisciplinary cooperation in Czech Republic has been established, family survivors are willing to receive genetic and cardiological care, while centralised molecular genetic analysis enables reliable results which are in accordance with other multicentric studies. The molecular autopsy should, especially in SIDS, be expanded to whole exome sequencing.

Preventive or Deferred Ablation of Ventricular Tachycardia in Patients With Ischemic Cardiomyopathy and Implantable Defibrillator (BERLIN VT)

Background:

Catheter ablation for ventricular tachycardia (VT) reduces the recurrence of VT in patients with implantable cardioverter-defibrillators (ICDs). The appropriate timing of VT ablation and its effects on mortality and heart failure progression remain a matter of debate. In patients with life-threatening arrhythmias necessitating ICD implantation, we compared outcomes of preventive VT ablation (undertaken before ICD implantation to prevent ICD shocks for VT) and deferred ablation after 3 ICD shocks for VT.

Methods:

The BERLIN VT study (Preventive Ablation of Ventricular Tachycardia in Patients With Myocardial Infarction) was a prospective, open, parallel, randomized trial performed at 26 centers. Patients with stable ischemic cardiomyopathy, a left ventricular ejection fraction between 30% and 50%, and documented VT were randomly assigned 1:1 to a preventive or deferred ablation strategy. The primary outcome was a composite of all-cause death and unplanned hospitalization for either symptomatic ventricular arrhythmia or worsening heart failure. Secondary outcomes included sustained ventricular tachyarrhythmia and appropriate ICD therapy. We hypothesized that preventive ablation strategy would be superior to deferred ablation strategy in the intention-to-treat population.

Results:

During a mean follow-up of 396±284 days, the primary end point occurred in 25 (32.9%) of 76 patients in the preventive ablation group and 23 (27.7%) of 83 patients in the deferred ablation group (hazard ratio, 1.09 [95% CI, 0.62–1.92]; P =0.77). On the basis of prespecified criteria for interim analyses, the study was terminated early for futility. In the preventive versus deferred ablation group, 6 versus 2 patients died (7.9% versus 2.4%; P =0.18), 8 versus 2 patients were admitted for worsening heart failure (10.4% versus 2.3%; P =0.062), and 15 versus 21 patients were hospitalized for symptomatic ventricular arrhythmia (19.5% versus 25.3%; P =0.27). Among secondary outcomes, the proportions of patients with sustained ventricular tachyarrhythmia (39.7% versus 48.2%; P =0.050) and appropriate ICD therapy (34.2% versus 47.0%; P =0.020) were numerically reduced in the preventive ablation group.

Conclusions:

Preventive VT ablation before ICD implantation did not reduce mortality or hospitalization for arrhythmia or worsening heart failure during 1 year of follow-up compared with the deferred ablation strategy.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02501005.

3256Long-term safety of stereotactic body radiotherapy for ablation of ventricular tachycardia: a multicentric study

Background

Contemporary stereotactic body radiotherapy (SBRT) enables to accurately concentrate high radiation doses to small volumes of myocardial tissue. There is a rising interest in using SBRT to modify arrhythmogenic substrate in patients with previously failed radiofrequency catheter ablation. However, data on the safety of SBRT for the treatment of VT are lacking.

Purpose

This study evaluated the long-term safety of SBRT for the treatment of VT.

Methods

SBRT was performed in patients with structural heart disease and failed catheter ablation for VT. The critical part of the VT substrate was identified by electroanatomic mapping (EAM) using a combination of voltage mapping, pace mapping, and activation mapping; and it was marked on a contrast-enhanced computer tomography study as a target for radioablation. SBRT was performed using a radiosurgery system with real-time motion tracking using the tip of the electrode of an indwelling defibrillator as a fiducial marker. A total radiation dose of 25 Gy was delivered to the ablation target in a single session during free breathing. Radiation-induced toxicity was evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.

Results

Between 2014 and 2018, 18 patients from two electrophysiology centres underwent SBRT for recurrent, drug-resistant VT after previously failed catheter ablation (17 male, 1 female; mean age 63±9 years; 14 ischemic cardiopathy, 3 dilated cardiopathy, 1 fibroma). The mean volume of the ablation target was 34±17 ml, and the mean duration of the therapy was 78±14 minutes. No patient exhibited acute (up to 3 months) elevation of troponin, pericardial effusion, or a decrease in left ventricular ejection fraction from baseline. Four patients developed acute mild nausea, which waned after antiemetic drugs. Two patients gradually developed significant progression of mitral regurgitation after SBRT. One of the patients was treated medically (grade 3 toxicity), but the other had to undergo mitral valve replacement (grade 4 toxicity). No other cardiac or pulmonary radiation related toxicity was observed during a median follow-up of 23 months. Three patients died at 54, 43, and 18 month after SBRT. None of the deaths was related to VT recurrence or complication of SBRT.

CARTO, Radiation dose and Survival

Conclusions

This is the largest series of patients who underwent EAM-guided SBRT for VT as a bailout therapy after previously failed radiofrequency catheter ablation. Our preliminary data indicate the feasibility and safety of the procedure. To further investigate long-term safety and efficacy of SBRT for VT, we initiated a prospective multicentric study (NCT03819504).

Acknowledgement/Funding

Supported by RVO-FNOs/2014

P4762What do atrial fibrillation ablation procedural volume differences across European centers reflect? An ESC EORP registry: atrial fibrillation long-term

Background

Data from the European Atrial Fibrillation (AF) Ablation Long-Term Registry suggest that there are significant differences in the volume of AF ablation procedures performed across different centers even in the same country. If these differences in AF ablation volume between centers reflect regional, socioeconomic, infrastructural/technical or other disparities has not been addressed till now.

Purpose

The aim of this study was to investigate patient and non-patient related differences among European AF ablation centers according to the volume of AF ablations performed.

Methods

Data for this analysis originate from the European AF Ablation Long-Term Study, a prospective registry designed to describe the clinical epidemiology of patients undergoing AF ablation. Based on 25th and 75th percentiles of AF ablation numbers performed, the participating centers were classified into high volume (HV) (≥250 procedures/year), medium volume (MV) (<250 and ≥58/year) and low volume (LV) (<58/year). Patient (demographics, comorbidities) and non-patient (center infrastructure, procedural characteristics) related differences were assessed.

Results

A total of 91 centers in 26 European countries enrolled 3368 patients. There were no significant differences concerning regional distribution, hospital/cardiology facilities or services provided among centers with the exception of electrophysiology procedures and labs which were more abundant in HV centers (p=0.02 and <0.001 respectively). HV and MV centers ablate twice more cases of long-standing persistent and persistent AF compared to LV centers, in which paroxysmal AF reaches 78.9% of all cases (Figure A). Accordingly, first AF ablation procedure was far more frequent in LV centers compared to MV and HV (85.8% vs 76.0% vs 76.1% respectively, p<0.001). Even though HV centers ablate significantly more high risk patients (CHA2DS2-VASc score ≥2 51.4% in HV vs 46.5% in MV vs 37.2% in LV, p<0.001) (Figure B) with accompanying comorbidities, applying more elaborate ablation techniques, fluoroscopy time and radiation dose were higher among patients undergoing AF ablation in LV centers (p<0.001 for all). Despite the above-mentioned dissimilarities, Kaplan-Meier survival analysis, based on adjusted data, demonstrated non-significant differences in complication rate (p=0.402) or AF recurrence rate (p=0.363) among HV, MV and LV centers.

Conclusions

Volume of AF ablations in a center is not correlated with regional or infrastructural characteristics. The higher volume in HV centers consists mainly by more long-term persistent AF and higher risk patients, suggesting that differences in volume reflect differences in experience and personnel's commitment towards AF ablation.

P4508Uncoupling of right ventricular and arterial elastance in advanced HFrEF predicts poor survival

Background

Right ventricular dysfunction (RVD) in heart failure (HF) is poorely understood and difficult to recognize due to complex RV geometry and load-dependency. Pressure volume analysis using SPECT ventriculography combined with right heart catheterisation (RHC) ar rest and during load-altering maneuver (7 min 60° leg rise, LR) can improve detection of RVD.

Methods

Advanced HF patients underwent RHC with thermodilution CO measurement (Corodyne, Braun, Germany) followed by gated 3D equilibrium Tc-labeled blood pool SPECT ventriculography (D-SPECT, Israel). QBS software was used to calculate chamber volumes to derive contractility (EF, elastance: Ees) and afterload (Ea). Patients were followed for occurence of death without Tx, urgent Tx or VAD implant.

Results

From 157 patients (age 55±12 years, LV EF 22±12%, 86% males), 83% had PH (mPA>25 mmHg) and 58% had RVD (RV EF <35%). Despite afterload (PAm, Ea) correlated with RV function (RVEF, RV Ees), it explained <10% of its variance; at rest or during LR. Leg rise led to significant (p<0.01) increases of RVEDP, PAWP, mPA (+2, +3, +4 mmHg), to increases of RVEDV, RVESV (+18 and +9 ml), but to reductions of LVEDV and LVESV (−14 and −9 ml) and to no change of RV or LV EF, CO, HR. LR inreased RV afterload (Ea), had no change on RV contractility but it further reduced RV-PA coupling (Ees/Ea). With LR, 70% of patients had relative increase in RV diastolic volume compared to LV (REDV/LVEDV ratio), reflecting RV diastolic reserve. After median of 112 (IQR: 33–229) days, 73 pts (46%) had an event (urgent Tx, VAD or death). In Cox analysis, both RVD and PH were associated with adverse outcome. From all volume- and pressure-derived measures acquired at rest and during LR, low resting RV coupling ratio (Ees/Ea) had strongest association with events (Z-standartized RR 0.4, 95% CI: 0.2–0.6, p<0.0001). Patients with larger relative increase in RV volume during LR (larger RV diastolic reserve) had better outcome.

Conclusion

Pressure-volume analysis of RV function provides more precise characterization of RV-PA coupling and allows better event-free survival prediction than isolated volumetric or hemodynamic indexes. Low resting RV Ees/Ea ratio (< median 0.324) predicts particularly poor survival.

Acknowledgement/Funding

Ministry of Health of the Czech republic, grant AZV 17-28784A

P1028Impact of atrial fibrillation ablation procedural volume on complication and recurrence rate across European centers. An ESC EORP registry: atrial fibrillation long-term

Background

Catheter ablation has emerged as an effective therapy in patients with symptomatic and drug refractory atrial fibrillation (AF). Despite high success rates of the method, there is still heterogeneity of outcomes and complication rate across Europe. The impact of the annual procedural volume per center on success and complication rate of AF ablation, based on real-life data, has not been addressed till now.

Purpose

The aim of the study was to investigate if center AF ablation volume might be associated with one-year success or complication rate after the procedure.

Methods

Data for this analysis were extracted from the European AF Ablation Long-Term Study, a prospective registry designed to describe the clinical epidemiology of patients undergoing AF ablation. Based on 25th and 75th percentiles of AF ablation numbers performed, the participating centers were classified into high volume (HV) (≥250 procedures/year), medium volume (MV) (<250 and ≥58/year) and low volume (LV) (<58/year). One-year success was defined as patient survival free from any atrial arrhythmia, from the end of the 3-month blanking period to 12 months following the ablation procedure.

Results

A total of 91 centers in 26 European countries enrolled 3368 patients. There was a significantly higher reporting of cardiovascular complications in LV centers (5.2%), especially pericarditis (0.6%) and cardiac perforation (1.4%), while the HV and MV centers reported cardiovascular complications in 3.0 and 4.3% of cases, respectively (p=0.039). Additionally, stroke incidence after ablation was significantly higher in LV centers (0.5% of cases vs 0% in HV and MV centers, p=0.008). Kaplan-Meier survival analysis based on adjusted data of all complications demonstrated, however, that there was not a significant difference in complication rate according to volume's center (p=0.402, Figure A). One-year success after AF ablation ranged from 77.8% in HV vs 70.5% in LV vs 77.3% in MV centers (p<0.001). Nonetheless, adjusted recurrence rate was not significantly different among centers (p=0.363, Figure B), a result driven by differences both in ablation technical characteristics and risk/severity of cases ablated in different volume centers.

Conclusions

Despite the notion that “the higher, the better”, our results suggest that AF ablation is a safe procedure with high success rates in all European centers, independent of the AF ablation procedural volume. Differences in patients and procedural characteristics may justify the equality of complication and recurrence rate among centers, since expertise level counterbalances the risk of each case.

5209Stereotactic radioablation of ventricular tachycardia guided by direct integration of 3D electroanatomic mapping: development and validation of a new method

Background

Stereotactic body radiotherapy (SBRT) has emerged as a promising bailout therapy for recurrent ventricular tachycardia (VT) in patients with failed radiofrequency catheter ablation. However, SBRT can function only if the ablation target is precisely identified.

Purpose

We sought to develop a novel method for direct integration of electroanatomic mapping (EAM) data to an SBRT work station for radioablation of VT.

Methods

Candidates for SBRT were patients with recurrent, drug-resistant VT who underwent ≥2 previous radiofrequency catheter ablations (CARTO 3, Biosense-Webster, Diamond Barr, CA) and continued to have inducible clinical VT or clinical recurrences of VT. At the end of the last catheter ablation, the operators performed additional EAM to obtain landmarks for image registration: aorta with the ostium of the left main coronary artery or left atrium with ostia of pulmonary veins. Correct position of the catheter at the landmark was verified by intra-cardiac echocardiography. VT substrate–defined by a combination of voltage mapping, pace mapping, and detection of local abnormal ventricular activity and/or late potentials was marked by custom tags as a target for SBRT. The CARTO maps were exported and converted to 3D shells with encoded EAM properties (VTK format). On the following day, the patients underwent contrast-enhanced computer tomography (CT) of the heart. Using 3D Slicer software 4.10 (slicer.org), the EAM-derived anatomical structures with the marked ablation target were projected onto CT images by landmark registration with manual correction. The CT study with the projected contours of the EAM-detected ablation target was imported as a DICOM-RT format into a stereotactic radiotherapy planning work station (Multiplan 3.5, Accuray, Sunnyvale, CA). SBRT was performed using a contemporary radiosurgery system with real-time motion tracking of the ablation target (CyberKnife 8.5, Accuray). The prescribed (X-ray) dose was 25 Gy during a single session.

Results

The proposed work-flow was verified in four patients with structural heart disease and drug-resistant VT who had 2–3 unsuccessful radiofrequency catheter ablations (all males; age: 68–78 years; left ventricular ejection fraction: 20–25%; ischemic/non-ischemic cardiomyopathy: 2/2). Integration of EAM data with CT was achieved in all patients. None of them experienced acute radiotoxicity after SBRT. At a follow-up checkup at one month, three of the patients remained arrhythmia-free. One patient experienced VT recurrence one day after SBRT, but no VTs recurred during the following month of follow-up.

Figure 1

Conclusions

This is the first report demonstrating the feasibility of SBRT of VT guided by direct integration of EAM. The proposed method is best suited as a bailout procedure for patients with previously failed catheter ablation.

Acknowledgement/Funding

M.S. was supported by ESC Research Fellowship 2018

5162Novel insights into desminopathy in the era of next generation sequencing

Aims

The pleomorphic clinical presentation makes the diagnosis of desminopathy difficult. This disease of intermediate filaments causes not only a contractile dysfunction in cardiomyopathy and skeletal myopathy, but also a secondary mitochondrial dysfunction. We aimed to describe prevalence, phenotypic expression and mitochondrial function in desmin mutation carriers identified in a large cohort of patients with unexplained cardiomyopathy.

Methods and results

A representative cohort of 327 Czech patients with unexplained cardiomyopathy underwent whole exome sequencing. The cohort consisted of cases with familial and sporadic dilated cardiomyopathy (81%), left ventricular noncompaction cardiomyopathy (LVNC) (13%), and less frequently of restrictive (3%) or arrhythmogenic cardiomyopathy (3%). Clinical and laboratory data of desmin mutation carriers were collected. Morphology, desmin expression and mitochondrial function were studied in available myocardial and skeletal muscle specimens.

Rare, conserved and possibly pathogenic desmin variants were identified in 6 (1.8%) probands. Two desmin mutations previously classified as variants of uncertain significance (p.K43E, p.S57L), one novel desmin variant (p.A210D) and two known pathogenic desmin mutations (p.R406W, p.R454W) were in affected individuals associated with characteristic pathological desmin aggregates in myocardial and/or skeletal biopsy samples. The individual with the novel desmin variant p.Q364H had decreased myocardial expression of desmin with absent desmin aggregates in myocardial/skeletal biopsy and presented with familial left ventricular non-compaction cardiomyopathy, a novel phenotype of desminopathy. Assessment of mitochondrial function in four carriers of desmin mutations with fresh-frozen skeletal and/or myocardial muscle specimens confirmed decreased metabolic capacity of mitochondrial respiratory chain complexes, which was in case of myocardial succinate respiration more profound than in end-stage heart failure of other etiologies. Genetic testing corrected an inappropriate clinical diagnosis in two probands previously diagnosed with mitochondrial disease and inflammatory cardiomyopathy. During a median follow-up of 56 months, 5 (83%) probands developed end-stage heart failure.

Conclusions

Desminopathy is a rare cause of cardiomyopathy and/or skeletal muscle myopathy with a pleomorphic clinical presentation and poor prognosis. The presence of desminopathy should be considered also in individuals with left ventricular non-compaction cardiomyopathy, and in the differential diagnosis of mitochondrial diseases and inflammatory cardiomyopathy.

Acknowledgement/Funding

Research grant of the Ministry of Health, Czech Republic [MZ 15-27682A], No. 00023001 (IKEM, Prague, CZ), the Czech Science Foundation [14-36804G].

P2844Novel temperature guided irrigated ablation catheter: reproducibility of procedural efficiencies and acute success to isolate the pulmonary veins from two multicenter, feasibility studies

Background/Introduction

The novel catheter with 6 thermocouples for real-time temperature monitoring during irrigated radiofrequency ablation was designed to potentially enhance safety and effectiveness of the Smart Touch Surround Flow (STSF) catheter by incorporating real-time temperature sensing. A supplementary, novel algorithm was developed to modulate power to maintain target temperature during high power/short duration ablation (90W, 4s).

Purpose

This sub-analysis was performed to examine consistency and reproducibility of the procedural efficiencies and acute success of the novel catheter with optimized temperature control and microelectrodes in treating paroxysmal atrial fibrillation (PAF) across multiple sites from two initial feasibility studies, in standard (QMODE) and high power/short duration (QMODE+) temperature-control ablation modes.

Methods

The QDOT-MICRO (QMODE, NCT02944968; N=42) and QDOT-FAST (QMODE+, NCT03459196; N=52) studies were both prospective, non-randomized multi-center, clinical investigations completed across 6 and 7 centers, respectively, in Europe. Procedural efficiencies and acute success (PVI via entrance block) was examined across sites within the study.

Results

In the QDOT-MICRO study, median procedure time (105–155 min), RF ablation time (27.7–39.5 min), and fluoroscopy times (2.2–8 min) during QMODE ablation were similar across the 6 sites. In QMODE+ ablation, median procedure time, RF ablation time, and fluoroscopy times all fall within (84–134 min), (4.8–9.7 min) and (1.1–9.6 min), respectively, across the 7 sites. Fluid delivery by the study catheter was low in both studies: QDOT-MICRO 547±278mL (mean ± SD); QDOT-FAST 382±299. mL (mean ± SD); which is 39.1 and 57.4% lower, respectively, than reported in the SMART SF trial. Esophageal temperature probe was used in the majority of patients (30/42 for QDOT MICRO and 51/52 for QDOT-FAST). Acute PVI was successful in 100% of patients in both studies with no deaths or unanticipated AEs.

Conclusion(s)

In both feasibility studies, procedural efficiencies were reproducible across study sites in both QMODE and QMODE+, with 100% acute success and good safety outcomes. Efficiencies are likely to improve with further experience. These results need to be confirmed in larger trials.

Acknowledgement/Funding

Both Studies are Company Sponsored Studies funded by Biosense Webster, Inc.

P341Which patients with atrial fibrillation undergo an ablation procedure today in Europe? A report from the ESC-EHRA-EURObservational Research Programme

Aims

Great heterogeneity in rhythm control management of patients with atrial fibrillation (AF) has been described. The aim of this study was to investigate how selective the patient cohort referred for AF ablation is, as compared to the general AF population in Europe, and to describe the governing mechanisms for such selection.

Methods

Descriptive comparative statistical analyses of the baseline characteristics were performed between the cohorts of Atrial Fibrillation Ablation Long-Term (ESC-EORP EHRA AFA-LT) Registry, designed to provide a picture of contemporary real-world AF ablation, and the AF population from the AF-General (ESC-EORP EHRA AF-Gen) PilotRegistry. Data collection was performed using a web-based system.

Results

In the AFA and in the AFG pilot registries 3593 and 3049 patients were enrolled, respectively. Patients who underwent AF ablation were younger,more commonly male, and had significantly less co-morbidities. Lone AF was predominant in AFA patients who were at lower risk of stroke (CHA2DS2-VASc >5: 2.9% vs. 24.5%, all P<0.001) and bleeding (HAS-BLED ≥2: 8.5% vs. 40.5%, P<0.001) but with EHRA scores >1 and more prevalentAF-related symptoms such as palpitations, fatigue and weakness (all p<0.001)as compared to the general AF patients. AFA patients were significantly more often male, had higher LV ejection fraction (59.5% vs. 52.4%) and smaller left atrial size on echocardiogram (P<0.001 each).

Conclusions

The comparison of the patient chorts in the AFA and AFG registries showed that AF ablation in European clinical practice is mostly performed in relatively young, symptomatic and otherwise relatively healthy patients.

Acknowledgement/Funding

Abbott Vascular Int.; Amgen Cardiovascular, AstraZeneca, Bayer, Boehringer Ingelheim, Boston Scientific, Bristol Myers Squibb and Pfizer Alliance

P3752Ablation of the superior left ganglionic plexus is not necessary for effective denervation of the sinoatrial and atrioventricular nodes

Background

Cardioneuroablation by targeting of atrial ganglionic plexi (GP) has been proposed as a new therapeutic option in selected patients with reflex syncope. Contribution of individual GPs to cardiac autonomic regulations is not fully established.

Purpose

Because consistent vagal responses have been observed during left superior pulmonary vein isolation in patients undergoing ablation for atrial fibrillation, we investigated whether standalone ablation of the superior left GP modifies the vagal input into the sinoatrial (SAN) and atrioventricular node (AVN).

Methods

Study hypothesis was investigated in otherwise healthy patients undergoing cardioneuroablation for symptomatic bradyarrhythmias. All had preprocedural atropine test suggesting functional disorder. Anatomically-navigated (CARTO-3) radiofrequency (RF) ablation (25–30 W/30 s/20 ml/min) at empirical GP sites was performed in general anaesthesia. Extracardiac high-frequency vagal nerve stimulation (25–60 V/30–50 Hz/0.05–0.1 ms) via right jugular vein was performed at baseline, after initial superior left GP ablation, and after the ablation of remaining septal and inferior GPs. High-frequency vagal nerve stimulation was always done in both sinus rhythm and atrial pacing. The elimination of all stimulation-induced vagal responses was the endpoint of the procedure.

Results

A study included 8 patients (34±8 years; 5 males). Six of them had recurrent syncope with cardioinhibitory response at the SAN (n=4), AVN (n=1) or both nodes (n=1); and 2 patients had symptomatic sinus bradycardia. At baseline, high-frequency vagal nerve stimulation induced long episodes of sinus arrest and advanced AV block in all patients. Cluster ablation at the superior left GP (RF time: 192±28 s) did not change the sinus rate (59±14 vs 60±15, NS), PQ interval (174±37 vs 173±37, NS), and did not induce any tangible change in SAN/AVN response to high-frequency vagal nerve stimulation. Subsequently, anterior right GP was targeted from the aspect of right atrium (n=7), from the anterior antrum of right pulmonary veins (n=6), and inferior GPs were targeted from the aspect of left atrium (n=7). This lesion set finally resulted in complete non-responsiveness of SAN and AVN to high-frequency vagal nerve stimulation in all patients. Ablation procedure overall (duration: 172±15 min; RF time: 988±306 s; radiation dose: 70±34 μGy·m2) led to sinus rate acceleration by a median of 29 (IQR: 18–38) bpm, increase of Wenckebach point by 21 (IQR: 9–28) bpm, and shortening of AVN effective refractory period by 40 (IQR: 15–73) ms.

Conclusions

Cardioneuroablation guided by extracardiac high-frequency vagal nerve stimulation can achieve complete denervation of SAN and AVN by ablation of postero(para)septal and inferior GPs only. Ablation of the superior left GP appears unnecessary and can be eliminated from the lesion set design.