Prevention of esophageal lesions during atrial fibrillation catheter ablation using esophageal temperature monitoring: A systematic review and meta-analysis

INTRODUCTION

The use of esophageal temperature monitoring (ETM) for the prevention of esophageal injury during atrial fibrillation (AF) ablation is often advocated. However, evidence supporting its use is scarce and controversial. We therefore aimed to review the evidence assessing the efficacy of ETM for the prevention of esophageal injury.

METHODS

We performed a meta-analysis and systematic review of the available literature from inception to December 31, 2022. All studies comparing the use of ETM, versus no ETM, during radiofrequency (RF) AF ablation and which reported the incidence of endoscopically detected esophageal lesions (EDELs) were included.

RESULTS

Eleven studies with a total of 1112 patients undergoing RF AF ablation were identified. Of those patients, 627 were assigned to ETM (56%). The overall incidence of EDELs was 9.8%. The use of ETM during AF ablation was associated with a non significant increase in the incidence of EDELs (12.3% with ETM, vs. 6.6 % without ETM, odds ratio, 1.44, 95%CI, 0.49, 4.22, p = .51, I2 = 72%). The use of ETM was associated with a significant increase in the energy delivered specifically on the posterior wall compared to patients without ETM (mean power difference: 5.13 Watts, 95% CI, 1.52, 8.74, p = .005).

CONCLUSIONS

The use of ETM does not reduce the incidence of EDELs during RF AF ablation. The higher energy delivered on the posterior wall is likely attributable to a false sense of safety that may explain the lack of benefit of ETM. Further randomized controlled trials are needed to provide conclusive results.

The influence of cardiac arrhythmias on the detection of heartbeats in the photoplethysmogram: benchmarking open-source algorithms

Objective.Cardiac arrhythmias are a leading cause of mortality worldwide. Wearable devices based on photoplethysmography give the opportunity to screen large populations, hence allowing for an earlier detection of pathological rhythms that might reduce the risks of complications and medical costs. While most of beat detection algorithms have been evaluated on normal sinus rhythm or atrial fibrillation recordings, the performance of these algorithms in patients with other cardiac arrhythmias, such as ventricular tachycardia or bigeminy, remain unknown to date.Approach. ThePPG-beatsopen-source framework, developed by Charlton and colleagues, evaluates the performance of the beat detectors namedQPPG,MSPTDandABDamong others. We applied thePPG-beatsframework on two newly acquired datasets, one containing seven different types of cardiac arrhythmia in hospital settings, and another dataset including two cardiac arrhythmias in ambulatory settings.Main Results. In a clinical setting, theQPPGbeat detector performed best on atrial fibrillation (with a medianF1score of 94.4%), atrial flutter (95.2%), atrial tachycardia (87.0%), sinus rhythm (97.7%), ventricular tachycardia (83.9%) and was ranked 2nd for bigeminy (75.7%) behindABDdetector (76.1%). In an ambulatory setting, theMSPTDbeat detector performed best on normal sinus rhythm (94.6%), and theQPPGdetector on atrial fibrillation (91.6%) and bigeminy (80.0%).Significance. Overall, the PPG beat detectorsQPPG,MSPTDandABDconsistently achieved higher performances than other detectors. However, the detection of beats from wrist-PPG signals is compromised in presence of bigeminy or ventricular tachycardia.

[Cardiology: what's new in 2023]

The year 2023 has been extremely rich in new publications in the various subfields of cardiology. Furthermore, the European Society of Cardiology (ESC) has issued revised guidelines focused on the management of acute coronary syndrome (ACS) and endocarditis, as well as an update on the recommendations for the management of heart failure and cardiovascular prevention. The most significant updates according to the Cardiology Department of CHUV are summarized in this review article.

The critical isthmus of left atrial anterior wall flutter is mostly circumscribed into a small area immediately behind the aortic root. Implications for catheter ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Left atrial flutters (LAFL) are typically observed in patients with previous ablation lines or surgery in the left atrium (LA). Less frequently, scar-related left atrial anterior wall (LAAW) flutters may occur. Although the presence of low-voltage areas (LVAs, a surrogate of scar) in the LA is considered an arrhythmogenic substrate and a marker of atrial cardiomyopathy, the pathophysiologic factors responsible for its formation remain unclear. We hypothesized that compression of the LAAW by the aortic root could be responsible of LVAs found in the LAAW, and therefore, be the substrate for the development of LAAW flutter.

Purpose

We aimed to describe: 1) the relationship between the aortic root and the presence of LVAs in the LAAW, which is the substrate for reentry; and 2) the clinical and electrophysiological characteristics of LAAW atrial flutter.

Methods

Consecutive patients referred for LAFL ablation between April 2019 and September 2022 in a single center were retrospectively collected. Among 55 patients with LAFL, 10 (18%) demonstrated a macroreentrant circuit with a critical isthmus identified in the LAAW, in the absence of previous ablation lines or surgery, and were included in the analysis. Previous pulmonary vein isolation (PVI) was not an exclusion criterion. All patients underwent a multidetector computerized tomography (MDCT) prior to the procedure and the images were analyzed using ADAS 3DTM imaging platform. Activation mapping was performed in all patients using a multielectrode mapping catheter and CARTO 3 navigation system.

Results

9 of 10 patients were male (mean age 74,3 ± 6,3 years). LA enlargement was present in all patients (48,3 ± 4,7 mm) and the mean aortic root diameter was 34,8 ± 3,4 mm. The mean LAAW flutter cycle length was 293,4 ± 68,3 ms. In 9 of the patients (90%), the LAAW flutter critical isthmus was just behind the aortic root, separated by < 1 mm according to the LA-aortic root fingerprinted isodistance map (mean fingerprinted isodistance area was 5,8 ± 2,5 cm2). The remaining patient had the critical isthmus just below the aortic root, between the area in contact with the latter and the mitral annulus. Furthermore, in all cases, the critical isthmus was immersed in LVAs. All but 1 LAAW flutter terminated during radiofrequency (RF) energy applications and rendered it non-inducible. After a median follow-up of 13,6 months (IQ range 5,3-21,6), 7 patients (70%) remained without recurrences.

Conclusion

In patients with LAAW atrial flutter, the presence of LVAs and the critical isthmus of the tachycardia are mostly circumscribed into small areas immediately behind the aortic root. Knowledge of this close relationship and the use of the isodistance map could be useful when mapping and ablating LAAW flutter, helping to straightforward the ablation procedure.

Personalized pulmonary vein antrum isolation guided by left atrial wall thickness for persistent atrial fibrillation

AIMS

Pulmonary vein (PV) antrum isolation proved to be effective for treating persistent atrial fibrillation (PeAF). We sought to investigate the results of a personalized approach aimed at adapting the ablation index (AI) to the local left atrial wall thickness (LAWT) in a cohort of consecutive patients with PeAF.

METHODS AND RESULTS

Consecutive patients referred for PeAF first ablation were prospectively enrolled. The LAWT three-dimensional maps were obtained from pre-procedure multidetector computed tomography and integrated into the navigation system. Ablation index was titrated according to the local LAWT, and the ablation line was personalized to avoid the thickest regions while encircling the PV antrum. A total of 121 patients (69.4% male, age 64.5 ± 9.5 years) were included. Procedure time was 57 min (IQR 50-67), fluoroscopy time was 43 s (IQR 20-71), and radiofrequency (RF) time was 16.5 min (IQR 14.3-18.4). The median AI tailored to the local LAWT was 387 (IQR 360-410) for the anterior wall and 335 (IQR 300-375) for the posterior wall. First-pass PV antrum isolation was obtained in 103 (85%) of the right PVs and 103 (85%) of the left PVs. Median LAWT values were higher for PVs without first-pass isolation as compared to the whole cohort (P = 0.02 for left PVs and P = 0.03 for right PVs). Recurrence-free survival was 79% at 12 month follow-up.

CONCLUSION

In this prospective study, LAWT-guided PV antrum isolation for PeAF was effective and efficient, requiring low procedure, fluoroscopy, and RF time. A randomized trial comparing the LAWT-guided ablation with the standard of practice is in progress (ClinicalTrials.gov, NCT05396534).

Reproducibility analysis of the computerized tomography angiography-derived left atrial wall thickness maps

BACKGROUND

Adapting the ablation index (AI) to the left atrial wall thickness (LAWT) derived from computed tomography angiography (CTA) allows for a personalized approach that showed to improve PVI safety and outcomes.

METHODS

Three observers with different degrees of experience performed complete LAWT analysis of CTA for 30 patients and repeated the analysis for 10 of these patients. Intra- and inter-observer reproducibility of these segmentations was assessed.

RESULTS

Geometric congruence of repeated reconstruction of LA endocardial surface showed that 99.4% of points in the 3D reconstructed mesh were within < 1 mm distance for the intra-observer variability and 95.1% for the inter-observer. For the LA epicardial surface, an 82.4% of points were within < 1 mm for intra-observer and a 77.7% for inter-observer. A 1.99% of points were further than 2 mm for the intra-observer and a 4.1% for the inter-observer. Colour agreement between LAWT maps showed that a 95.5% and a 92.9% intra- and inter-observer respectively presented the same colour or a change to the colour immediately above or below. The ablation index (AI), which was adapted to this LAWT colour maps to perform a personalized pulmonary vein isolation (PVI), showed an average difference in the derived AI lower than 25 units in all cases. For all analyses, the concordance increased with user-experience.

CONCLUSION

Geometric congruence of LA shape was high, for both endocardial and epicardial segmentations. LAWT measurements were reproducible, increasing with user experience. This translated into a negligible impact in the target AI.

[Cardiology: what's new in 2022]

The year of 2022 was marked by many novelties in the fields of interventional cardiology, heart failure, electrophysiology, cardiac imaging, and congenital heart disease. These advances will certainly change our daily practice, on top of improving the diagnosis and treatment of many heart conditions. In addition, the European Society of Cardiology has updated its guidelines on pulmonary hypertension, ventricular arrhythmias and sudden death, cardiovascular assessment of patients undergoing non-cardiac surgery. The members of the Cardiology division of Lausanne University Hospital (CHUV) here present the publications which they considered to be the most important of the past year.

Preventive substrate ablation in chronic post-myocardial infarction patients with high-risk scar characteristics for ventricular arrhythmias: rationale and design of PREVENT-VT study

BACKGROUND

Recent studies showed that an early strategy for ventricular tachycardia (VT) ablation resulted in reduction of VT episodes or mortality. Cardiac magnetic resonance (CMR)-derived border zone channel (BZC) mass has proved to be a strong non-invasive predictor of VT in post-myocardial infarction (MI). CMR-guided VT substrate ablation proved to be safe and effective for reducing sudden cardiac death (SCD) and VA occurrence.

METHODS

PREVENT-VT is a prospective, randomized, multicenter, and controlled trial designed to evaluate the safety and efficacy of prophylactic CMR-guided VT substrate ablation in chronic post-MI patients with CMR-derived arrhythmogenic scar characteristics. Chronic post-MI patients with late gadolinium enhancement (LGE) CMR will be evaluated. CMR images will be post-processed and the BZC mass measured: patients with a BZC mass > 5.15 g will be eligible. Consecutive patients will be enrolled at 3 centers and randomized on a 1:1 basis to undergo a VT substrate ablation (ABLATE arm) or optimal medical treatment (OMT arm). Primary prevention ICD will be implanted following guideline recommendations, while non-ICD candidates will be implanted with an implantable cardiac monitor (ICM). The primary endpoint is a composite outcome of sudden cardiac death (SCD) or sustained monomorphic VT, either treated by an ICD or documented with ICM. Secondary endpoints are procedural safety and efficiency outcomes of CMR-guided ablation.

DISCUSSION

In some patients, the first VA episode causes SCD or severe neurological damage. The aim of the PREVENT-VT is to evaluate whether primary preventive substrate ablation may be a safe and effective prophylactic therapy for reducing SCD and VA occurrence in patients with previous MI and high-risk scar characteristics based on CMR.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04675073, registered on January 1, 2021.

Relationship between the posterior atrial wall and the esophagus: esophageal position and temperature measurement during atrial fibrillation ablation (AWESOME-AF). A randomized controlled trial

BACKGROUND

Pulmonary vein isolation (PVI) implies unavoidable ablation lesions to the left atrial posterior wall, which is closely related to the esophagus, leading to several potential complications. This study evaluates the usefulness of the esophageal fingerprint in avoiding temperature rises during paroxysmal atrial fibrillation (PAF) ablation.

METHODS

Isodistance maps of the atrio-esophageal relationship (esophageal fingerprint) were derived from the preprocedural computerized tomography. Patients were randomized (1:1) into two groups: (1) PRINT group, the PVI line was modified according to the esophageal fingerprint; (2) CONTROL group, standard PVI with operator blinded to the fingerprint. The primary endpoint was temperature rise detected by intraluminal esophageal temperature probe monitoring. Ablation settings were as specified on the Ablate BY-LAW study protocol.

RESULTS

Sixty consecutive patients referred for paroxysmal AF ablation were randomized (42 (70%) men, mean age 60 ± 11 years). Temperature rise (> 39.1 °C) occurred in 5 (16%) patients in the PRINT group vs. 17 (56%) in the CONTROL group (p < 0.01). Three AF recurrences were documented at a mean follow-up of 12 ± 3 months (one (3%) in the PRINT group and 2 (6.6%) in the CONTROL group, p = 0.4).

CONCLUSION

The esophageal fingerprint allows for a reliable identification of the esophageal position and its use for PVI line deployment results in less frequent esophageal temperature rises when compared to the standard approach. Further studies are needed to evaluate the impact of PVI line modification to avoid esophageal heating on long-term outcomes. The development of new imaging-derived tools could ultimately improve patient safety (NCT04394923).

Refractory ventricular tachycardia treated by a second session of stereotactic arrhythmia radioablation

•

Arrhythmia radioablation (STAR) is effective in refractory ventricular tachycardia.

•

We report the first cases of successful re-irradiation of arrhythmogenic substrate.

•

No radiation toxicity was observed after the second STAR.

•

Caution is advised as data on early and late toxicities remain scarce.

Purpose

Stereotactic arrhythmia radioablation (STAR) is an effective treatment for refractory ventricular tachycardia (VT), but recurrences after STAR were recently published. Herein, we report two cases of successful re-irradiation of the arrhythmogenic substrate.

Cases

We present two cases of re-irradiation after recurrence of a previously treated VT with radioablation at a dose of 20 Gy. The VT exit was localized on the border zone of the irradiated volume, which responded positively to re-irradiation at follow-up.

Conclusion

These two cases show the technical feasibility of re-irradiation to control recurrent VT after a first STAR.

[Epicardial adipose tissue and atrial fibrillation]

Atrial fibrillation (AF) is the most common arrhythmia encountered in adults; it is associated with a significant morbidity and mortality. Obesity is a risk factor contributing to AF occurrence. Recently, interest has focused on epicardial adipose tissue (EAT), defined as a fatty deposit located between the epicardium and the visceral pericardium. Its characteristics are distinct from classic adipose deposits: it infiltrates the epicardial myocardium and secretes cytokines, which modulate cardiomyocyte electrophysiology and cardiac remodeling. Different studies show that EAT can be an independent risk factor for AF and that EAT thickness, as measured by CT or MRI, could predict the presence, severity and recurrence of AF.

Programmed ventricular stimulation for risk stratification in patients with myocardial scarring and an ejection fraction above or equal to 40%

Funding Acknowledgements

Type of funding sources: None.

Background

Sudden cardiac death (SCD) is one of the leading causes of death, particularly among patients with myocardial scars. Implantable cardioverter defibrillators (ICD) are recommended in patients with a left ventricular ejection fraction (LVEF) ≤ 35%. Another recognised indication is the induction of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) during programmed ventricular stimulation (PVS) in post-myocardial infarction patients with non-sustained VT and a LVEF between 35% and 40%. However, no recommendation exists to guide the use of prophylactic ICD implantation in patients with less altered LVEF, even though they represent the majority of SCDs.

Purpose

We aimed to evaluate the prognostic value of PVS in patients with myocardial scars and a relatively preserved LVEF (≥ 40%).

Methods

Patients with evidence of a chronic myocardial scar and a LVEF ≥ 40%, who underwent PVS at two hospital centers were considered for inclusion. Ischemic and non-ischemic myocardial scars were included. The primary endpoint was the occurrence of a Major Arrhythmic Event (MAE), namely SCD, clinical VT/ventricular fibrillation, or appropriate ICD therapy.

Results

134 patients were included (mean age 62.4 ± 12.5 years, LVEF 54.7 ± 8.6 %). Indication for PVS was mostly non-sustained VT and/or syncope (84%). Post-myocardial infarction patients represented about half of the cases (53%). Inducibility during PVS was observed in 17 patients (13%). There was a nonsignificant trend towards higher inducibility rates in ischemic versus nonischemic scars (17% and 8%, respectively; p-value = 0.1). Of these patients, 15 received an ICD (88%). Over a mean follow-up of 49 (±42) months, a MAE occurred in 7 patients (41.2%) with positive PVS, versus 4 patients (3.4%) with negative PVS. MAE-free survival at 10 years was 91% and 43% in PVS-negative and PVS-positive patients, respectively (p-value &lt; 0.001). One SCD occurred in a PVS-positive patient who denied prophylactic ICD implantation. Inducibility during PVS provided a 64% sensitivity and a 97% negative predictive value (PV) to predict the occurrence of MAE (specificity 92%, positive PV 41%).

Conclusion

PVS is a useful tool to discriminate patients with myocardial scars and LVEF ≥ 40% at increased arrhythmic risk. Effective utilisation of ICD may be anticipated in case of positive PVS, while non-inducible patients are at lower MAE risk.

Multidetector computed tomography identification of previous ablation lines: insights for left atrial flutter ablation

Funding Acknowledgements

Type of funding sources: None.

Background

Left atrial flutter (LAFL) frequently occurs in patients with history of previous left atrial (LA) ablation. LAFL ablation is still considered a challenging and time-consuming procedure (1). Conduction gaps on ablation lines are frequently due to non-transmural or non-contiguous lesions. It was recently demonstrated that aiding AF ablation procedures with the integration of multidetector computed tomography (MDCT)-derived left atrial wall thickness (LAWT) maps into the navigation system allowed decreasing radiofrequency (RF) delivery, fluoroscopy, and procedure time while obtaining a high rate of first-pass isolation (2).

Purpose

We hypothesized that MDCT-derived 3D-LAWT map could be useful to aid LAFL ablation procedure in patients with previous LA ablation lines.

Methods

Consecutive patients with history of previous LA ablation who underwent LAFL ablation were prospectively enrolled from a single referral center. LAWT three-dimensional maps were obtained from MDCT and integrated into the navigation system. LAWT information was used to focus mapping in the areas of the probable crucial isthmus: the presence of previous ablation lines was searched at the level of linear segments with reduced parietal thickness at the LAWT-maps (LAWT &lt;1mm), while the search for conduction gaps was started at the level of the thicker areas of these lines. Conduction gap was defined as the presence of peak-to-peak bipolar potentials &gt; 0.5 mV at the level of the previous ablation line or as the presence during arrhythmia of a LAT delay &lt;30 ms between contiguous points lying in the same axial plane at the two sides of the line. Ablation was performed transecting the crucial isthmus with the documentation of bidirectional block; ablation first-attempt was guided by color-coded maps by connecting the parts of identified previous ablation lines with reduced LAWT. Finally, RF delivery was adapted to the local LAWT.

Results

Five patients [4 (80%) male, age 62 years (57-73)] were included. LAWT-aided LAFL ablation procedures had a median procedure time of 78 minutes (75-114) and a RF time of 5.9 minutes (4.7-8.5); fluoroscopy time was 3.2 minutes (1.5-3.6) with a fluoroscopy dose of 6.1 Gy*cm2 (2.8-8.2). Mean wall thickness of the gap zone was significantly higher with respect to the thickness of the zones of previous ablation lines (1.8 ± 0.5 mm vs. 1.0 ± 0.4 mm, p=0.047). All patients presented sinus rhythm at the end of the procedure and no acute complication occurred. No patient reported arrhythmic recurrence at 1-year follow-up (Figure 2).

Conclusions

LAWT-aided approach for LAFL ablation can facilitate identifying the wall thinning produced by the previous RF ablation line and the gap (seen as relative wall thickening) acting as the isthmus for the reentry circuit. This, in turn might help analysis of reentry circuits and increase procedure efficacy and efficiency. Further data are needed to reproduce these findings in a larger study cohort.

Personalized persistent atrial fibrillation ablation guided by left atrial wall thickness: a multicenter study

Funding Acknowledgements

Type of funding sources: None.

Background

Pulmonary vein isolation (PVI) has been proven to be effective in treating persistent atrial fibrillation (PeAF), although long-term ablation outcomes have been significantly less satisfactory than in paroxysmal AF (1). A recent personalized PVI approach, aiming for contiguous lesions with ablation index (AI) titration according to the local left atrial wall thickness (LAWT) as per multidetector cardiac tomography (MDCT), has demonstrated to achieve an arrhythmia-free survival &gt; 95% at 12 months in patients with paroxysmal AF (2).

Purpose

We sought to investigate the safety and clinical outcomes of this personalized PVI approach guided by LAWT in patients with PeAF.

Methods

Consecutive patients referred for PeAF first ablation were prospectively enrolled from three referral centers. PeAF was defined in the presence of at least one AF episode sustained beyond 7 days. LAWT three-dimensional maps were obtained from MDCT and integrated into the navigation system. LAWT was categorized into 1 mm layers and AI was titrated to the LAWT. The ablation line was personalized to avoid thicker regions (Figure 1) while encircling PV antrum. Follow-up was scheduled at 1, 3, 6, and every 12-months thereafter.

Results

One hundred twenty-seven patients [89 (70.6%) male, age 64 ± 10 years] were included. 68 (60.7%) patients were hypertensive, 10 (18%) patients suffered of type 2 diabetes, and mean CHA2DS2-VASc score was 2.3 ± 2.1. Mean procedure time was 61 ± 20 minutes and mean fluoroscopy time was 1.3 ± 2.2 minutes. Radiofrequency (RF) time was 9.0 ± 2.3 minutes for the right pulmonary veins with a first-pass isolation in 109 (85.8%) patients and 7.6 ± 1.9 minutes for the left pulmonary veins with first-pass in 110 (86.6%). No major complication occurred. The rate of survival free from AF recurrences at a mean follow-up of 12 ± 6 months was 82% (Figure 2).

Conclusions

Personalized Persistent AF ablation by wide circle PV isolation guided by LAWT, proved to be safe and highly efficient, requiring a low amount of RF delivery, procedure time, and fluoroscopy use, while obtaining a high rate of first-pass isolation and of freedom from AF recurrences.

New Insights in Central Venous Disorders. The Role of Transvenous Lead Extractions

Over the last decades, the implementation of new technology in cardiac pacemakers and defibrillators as well as the increasing life expectancy have been associated with a higher incidence of transvenous lead complications over time. Variable degrees of venous stenosis at the level of the subclavian vein, the innominate trunk and the superior vena cava are reported in up to 50% of implanted patients. Importantly, the number of implanted leads seems to be the main risk factor for such complications. Extraction of abandoned or dysfunctional leads is a potential solution to overcome venous stenosis in case of device upgrades requiring additional leads, but also, in addition to venous angioplasty and stenting, to reduce symptoms related to the venous stenosis itself, i.e., the superior vena cava syndrome. This review explores the role of transvenous lead extraction procedures as therapeutical option in case of central venous disorders related to transvenous cardiac leads. We also describe the different extraction techniques available and other clinical indications for lead extractions such as lead infections. Finally, we discuss the alternative therapeutic options for cardiac stimulation or defibrillation in case of chronic venous occlusions that preclude the implant of conventional transvenous cardiac devices.

Relationship between the posterior atrial wall and the esophagus: esophageal position during atrial fibrillation ablation

Background

Atrial fibrillation ablation implies a risk of esophageal thermal injury. Esophageal position can be analyzed with imaging techniques, but evidence for esophageal mobility is inconsistent.

Objectives

The purpose of this study was to analyze esophageal position stability from one procedure to another and during a single procedure.

Methods

Esophageal position was compared in 2 patient groups. First, preprocedural multidetector computerized tomography (MDCT) of first pulmonary vein isolation and redo intervention (redo group) was segmented with ADAS 3D™ to compare the stability of the atrioesophageal isodistance prints. Second, 3 imaging modalities were compared for the same procedure (multimodality group): (1) preprocedural MDCT; (2) intraprocedural fluoroscopy obtained with the transesophageal echocardiographic probe in place with CARTOUNIVU™; and (3) esophageal fast anatomic map (FAM) at the end of the procedure. Esophageal position correlation between different imaging techniques was computed in MATLAB using semiautomatic segmentation analysis.

Results

Thirty-five redo patients were analyzed and showed a mean atrioesophageal distance of 1.2 ± 0.6 mm and a correlation between first and redo procedure esophageal fingerprint of 91% ± 5%. Only 3 patients (8%) had a clearly different position. The multi-imaging group was composed of 100 patients. Esophageal position correlation between MDCT and CARTOUNIVU was 82% ± 10%; between MDCT and esophageal FAM was 80% ± 12%; and between esophageal FAM and CARTOUNIVU was 83% ± 15%.

Conclusion

There is high stability of esophageal position between procedures and from the beginning to the end of a procedure. Further research is undergoing to test the clinical utility of the esophageal fingerprinted isodistance map to the posterior atrial wall.

Personalized paroxysmal atrial fibrillation ablation by tailoring ablation index to the left atrial wall thickness: the 'Ablate by-LAW' single-centre study-a pilot study

AIMS

To determine if adapting the ablation index (AI) to the left atrial wall thickness (LAWT), which is a determinant of lesion transmurality, is feasible, effective, and safe during paroxysmal atrial fibrillation (PAF) ablation.

METHODS AND RESULTS

Consecutive patients referred for PAF first ablation. Left atrial wall thickness three-dimensional maps were obtained from multidetector computed tomography and integrated into the CARTO navigation system. Left atrial wall thickness was categorized into 1 mm layers and AI was titrated to the LAWT. The ablation line was personalized to avoid thicker regions. Primary endpoints were acute efficacy and safety, and freedom from atrial fibrillation (AF) recurrences. Follow-up (FU) was scheduled at 1, 3, 6, and every 6 months thereafter. Ninety patients [60 (67%) male, age 58 ± 13 years] were included. Mean LAWT was 1.25 ± 0.62 mm. Mean AI was 366 ± 26 on the right pulmonary veins with a first-pass isolation in 84 (93%) patients and 380 ± 42 on the left pulmonary veins with first-pass in 87 (97%). Procedure time was 59 min (49-66); radiofrequency (RF) time 14 min (12.5-16); and fluoroscopy time 0.7 min (0.5-1.4). No major complication occurred. Eighty-four out of 90 (93.3%) patients were free of recurrence after a mean FU of 16 ± 4 months.

CONCLUSION

Personalized AF ablation, adapting the AI to LAWT allowed pulmonary vein isolation with low RF delivery, fluoroscopy, and procedure time while obtaining a high rate of first-pass isolation, in this patient population. Freedom from AF recurrences was as high as in more demanding ablation protocols. A multicentre trial is ongoing to evaluate reproducibility of these results.

Personalized atrial fibrillation ablation by tailoring ablation index to the left atrial wall thickness. the ablate by-law single center study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Teres is funded by the research fellowship grant from the Swiss Heart Rhythm Foundation, Dr Carreno was funded was funded by a Scholarship from Sociedad Española de Cardiología (SEC).

Introduction

Left atrial wall thickness (LAWT) is a determinant of transmural lesion formation during atrial fibrillation (AF) ablation. The utility of ablation index (AI) to dose radiofrequency (RF) delivery for the reduction of AF recurrences has already been proven with a target AI ≥ 400 at the posterior wall and ≥550 at the anterior wall.

Objective

To determine if adapting AI to atrial wall thickness (AWT) is feasible, effective and safe during AF ablation.

Methods

Consecutive patients referred for a first PAF ablation. LAWT 3D-maps were obtained from multidetector computed tomography (MDCT) and integrated into the CARTO navigation system. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium and categorized into 1mm-layers and AI was titrated to the LAWT, as follows: Thickness &lt; 1 mm (red): 300; 1-2 mm (yellow): 350; 2-3 mm (green): 400; 3-4 mm (blue): 450; &gt; 4 mm (purple): 450 (Figure). The ablation line was designed in a personalized fashion to avoid thicker regions. All ablation procedures were performed under general anesthesia with a high frequency low-volume ventilation. Primary endpoints were acute efficacy and safety, and freedom from AF recurrences. Follow-up (FU) was scheduled at 1, 3, 6, and every 6 months thereafter.

Results

90 patients [60 (67 %) male, age 58 ± 13 years] were included. Mean LAWT was 1.25 ± 0.62 mm. Mean AI was 366 ± 26 on the right pulmonary veins (RPVs) with a first-pass isolation in 84 (93%) patients and 380 ± 42 on the left pulmonary veins (LPVs) with first-pass in 87 (97%). Procedure time was 59 min [49-66]; RF time 14 min [12,5-16]; fluoroscopy time 0.7 min [0.5-1.4]. No major complication occurred. Eighty-six out of 90 (95.5%) patients were free of recurrence after a mean FU of 11 ± 4 months.

Conclusions

 Personalized AF ablation, adapting the AI to LAWT allowed decreasing RF delivery, fluoroscopy and procedure time while obtaining a high rate of first-pass isolation. Lesion durability as estimated by freedom from AF recurrences was as high as in more demanding ablation protocols. Abstract Figure. Personalized protocol and results

Esophagus-to-posterior Atrial wall relationship: pre- and Intra-procedural three-dimensional multimodality imaging for esophageal position

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Teres was funded by the research fellowship grant of the Swiss Heart Rhythm Foundation. Dr Carreno-Lineros was funded by a Scholarship from Sociedad Española de Cardiología (SEC).

Introduction

  pulmonary vein isolation (PVI) approach implies unavoidable ablation  on the posterior atrial wall which is closely related to the esophagus. PVI may result in several complications.

Objective

the present study aims to analyze the stability of the esophageal position inside the mediastinum at the level of the posterior atrial wall from one procedure to another (Redo group) and during a single procedure (multi-image group).

Methods

the esophageal position was compared in two groups. First, pre-procedural multidetector computerized tomography (MDCTs) of the first PVI and the redo intervention (Redo group) were segmented with ADAS 3D™ software to compare the esophageal position and the atrio-esophageal distance prints (Figure A). Second, three imaging modalities were compared for the same procedure (multi-image group): i) preprocedural MDCT; ii) intraprocedural fluoroscopy obtained with the TEE probe in place in three projections with CARTOUNIVU™ (Biosense Webster); and iii) esophageal fast-anatomical map (FAM) obtained at the end of the procedure (Figure D). Ablation procedures were performed under general anesthesia. Exclusion criteria were unavailability or contraindication to obtain any of the techniques. The 3D correlation of the esophageal position acquired with different techniques, was computed in Matlab using semiautomatic segmentation analysis.

Results

35 patients were analyzed for the Redo group. Mean age 61 ± 10 years, 17 (65%) male, mean LVEF 57 ± 7%, mean LA diameter 43 ± 5 mm, median time since previous ablation (and therefore between MDCT acquisitions) was 6 months (IQR 3-9). Mean atrio-esophageal distance for both MDCTs was 1.2 ± 0.6 mm . The esophageal trajectory as related to the atrial posterior wall was left for 20 (57%) patients, central for 6 (18%) patients, and right for 3 (9%) patients, left-central for 4 (11%) patients, and right-central for 2 (5%) patients. There was a 91 ± 5% correlation on the esophageal position between the first procedure and the redo procedure MDCT. In 3 cases the position was clearly different with a correlation of only 40 ± 22%. The multi-imaging group was composed of 100 patients, mean age 61 ± 10 years, 17 (65%) male, mean LVEF 56 ± 7%, mean LA diameter 39 ± 6 mm. The esophageal trajectory as related to the atrial posterior wall was left for 55 (55%) patients, central for 23 (23%) patients, and right for 9 (9%) patients, left-central for 8 (8%) patients, and right-central for 5 (5%) patients. The correlation between MDCT and CARTOUNIVU™ was 82 ± 10% (Figure B); between MDCT and ESOFAM 80 ± 12% (Figure B); and between ESOFAM and CARTOUNIVU™ 83 ± 15% (Figure C).

Conclusions

There is a high stability of the esophageal position between procedures and from the beginning to the end of procedure. This observation needs to be tested for its clinical utility by designing studies that take into account the esophagus distance print to modulate RF delivery Abstract Figure. Multimodal Esophageal imaging

Left atrial wall thickness of the pulmonary vein reconnection sites during atrial fibrillation redo procedures

BACKGROUND

Left atrial wall thickness (LAWT) has been related to pulmonary vein (PV) reconnections after atrial fibrillation (AF) ablation. The aim was to integrate 3D-LAWT maps in the navigation system and analyze the relationship with local reconnection sites during AF-redo procedures.

METHODS

Consecutive patients referred for AF-redo ablation were included. Procedure was performed using a single catheter technique. LAWT maps obtained from multidetector computerized tomography (MDCT) were imported into the navigation system. LAWT of the circumferential PV line, the reconnected segment and the reconnected point, were analyzed.

RESULTS

Sixty patients [44 (73%) male, age 61 ± 10 years] were included. All reconnected veins were isolated using a single catheter technique with 55 min (IQR 47-67) procedure time and 75 s (IQR 50-120) fluoroscopy time. Mean LAWT of the circumferential PV line was 1.46 ± 0.22 mm. The reconnected segment was thicker than the rest of segments of the circumferential PV line (2.05 + 0.86 vs. 1.47 + 0.76, p < .001 for the LPVs; 1.55 + 0.57 vs. 1.27 + 0.57, p < .001 for the RPVs). Mean reconnection point wall thickness (WT) was at the 82nd percentile of the circumferential line in the LPVs and at the 82nd percentile in the RPVs.

CONCLUSION

A single catheter technique is feasible and efficient for AF-redo procedures. Integrating the 3D-LAWT map into the navigation system allows a direct periprocedural estimation of the WT at any point of the LA. Reconnection points were more frequently present in thicker segments of the PV line. The use of 3D-LAWT maps can facilitate reconnection point identification during AF-redo ablation.

Premature ventricular complex site of origin and ablation outcomes in patients with prior myocardial infarction

BACKGROUND

Frequent premature ventricular complexes (PVCs) are common after a myocardial infarction (MI), but data on PVC ablation in this population are limited.

OBJECTIVE

The purpose of this study was to analyze data on PVC ablation in post-MI patients.

METHODS

Three hundred thirty-two patients with frequent PVCs and left ventricular (LV) dysfunction were prospectively studied. Data from 67 patients (20%; age 63 ± 10 years; 65 men [93%]) with previous MI were compared with the remaining 265 patients.

RESULTS

PVCs in post-MI patients originate predominantly from the LV (92% LV vs 6% right ventricle [RV]; P <.001). The most frequent sites of origin (SOO) were MI scar in 23 patients (34%) and left ventricular outflow tract (LVOT) in 22 patients (33%). A papillary muscle origin was more frequent in post-MI patients (16% vs 4%; P = .001), whereas an RV outflow tract origin was less frequent (1% vs 33%; P <.001) compared to patients without MI. In post-MI patients, PVC burden decreased from 29% ± 12% at baseline to 4.6% ± 7% (P <.001); left ventricular ejection fraction (LVEF) improved from 33.6% ± 8% to 42% ± 10% (P <.001); and New York Heart Association functional class improved from 2.1 ± 0.7 to 1.4 ± 0.5 points (P <.001) at 12 months. Compared with the remaining 265 patients, there were no differences in acute ablation success (85% vs 85%; P = .45), complication rate (6% vs 6%; P = .41), or absolute improvement in LVEF (8.8 ± 10 vs 9.9 ± 11 absolute points; P = .38).

CONCLUSION

PVC ablation significantly improves cardiac function and functional status in post-MI patients. PVCs predominantly originate from MI scar and LVOT. A papillary muscle SOO was found to be strongly associated with previous MI.

P1111Arrhythmogenic substrate detection in ischemic patients undergoing ventricular tachycardia ablation using multi-detector computed tomography: compared evaluation with cardiac magnetic resonance

Background

 Cardiac magnetic resonance (CMR) is capable of accurately identifying arrhythmogenic substrate (AS), leading to longer arrhythmia-free survival when used to guide ventricular tachycardia (VT) substrate ablation procedures. However, the use of CMR may be limited in certain centers or patient subsets. 

Purpose

 To evaluate the performance of multidetector cardiac computed tomography (MDCT) imaging in identifying heterogeneous tissue channels (HTCs) detected by CMR in ischemic patients undergoing VT substrate ablation.

Methods

 Thirty ischemic patients undergoing both CMR and MDCT before VT substrate ablation were included. Using a dedicated post-processing software, two blinded operators, assigned either to CMR or MDCT analysis, characterized the presence of CMR- and CT-channels, respectively. CMR-channels were classified as endocardial (layers &lt;50%), epicardial (layers ≥50%) or transmural. CMR- vs. CT-channel concordance was considered when the orientation was the same and they were located in the same AHA segment.

Results

 Mean age was 69 ± 10 years; 90% were male. Mean left ventricular ejection fraction (LVEF) was 35 ± 10%. All patients had CMR-channels (n = 76), whereas only 26/30 (86.7%) had CT-channels (n = 91). Global sensitivity (Se) and positive predictive values (PPV) for detecting CMR-channels were 61.8% and 51.6%, respectively. MDCT performance improved in patients with epicardial CMR-channels (Se 80.5%), and transmural scars (Se 72.2%). In 4/11 (36%) patients with subendocardial MI, MDCT was unable to identify the AS.

Conclusion

 MDCT fails to detect the presence of AS in 36% of patients with subendocardial MI and shows a modest sensitivity identifying the presence of HTCs, although its performance improves in patients with transmural scar.

Abstract Figure. Multimodality imaging AS detection

1244Feasibility, safety and efficacy of tailoring ablation index to left atrial wall thickness (lawt) during atrial fibrillation ablation. The Ablate By-LAW Study

Funding Acknowledgements

Dr Teres was funded by Swiss Heartrhythm Foundation

Introduction

Circumferential pulmonary vein isolation (PVI) has become a mainstay in the treatment of atrial fibrillation (AF). The utility of ablation index (AI) to dose radiofrequency delivery for the reduction of AF recurrences has already been proven with a target AI ≥ 400 at the posterior wall and ≥550 at the anterior Wall. Nevertheless, the left atrial wall is a thin, heterogeneous structure with an important inter and intra-patient variability of LAWT.

Objective

To determine if adapting AI to atrial wall thickness (AWT) is feasible, effective and safe during AF ablation.

Methods

Single-Center study that included 80 consecutive patients referred for a first paroxysmal AF ablation that was performed with a single catheter approach with the intention to reduce vascular access complication rate. All patients had a MDCT prior to the ablation procedure. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium. All procedures were performed under general anesthesia with a high-rate low-volume ventilation protocol for obtaining higher catheter stability. The transeptal puncture was TEE-guided. During the procedure, the WT map was fused with the LA anatomy using CARTO-merge. LAWT was categorized into 1mm-layers and the AI was titrated to the local atrial WT as follows: Thickness &lt; 1 mm (red): 300; 1-2 mm (yellow): 350; 2-3 mm (green): 400; 3-4 mm (blue): 450; &gt; 4 mm (purple): 450 (Figure). Maximal inter-lesion distance was set at 6 mm. VisiTag settings were: catheter position stability: minimum time 3 s, maximum range 4 mm; force over time: 25%, minimum force 3 g; lesion tag size: 3 mm. Respiration training was not possible due to the high catheter stability.  The circumferential ablation line was designed in a personalized fashion to avoid thicker regions.

Results

80 patients [41 (51,2 %) male, age 60± 11 years] were included. Mean LVEF was 59 ± 5 %, Mean LA diameter 39,1 ± 5,8 mm, Mean LAWT was 1.36 ± 0.63 mm. Mean AI was 352 ± 36 on the RPVs and 356 ± 36 on the LPVs. Procedure time was 60,0 min (IQR 51-70). Fluoroscopy time was 58,5 s (35-97,5). First pass isolation was obtained in 72 (90%) of the RPVs and 75 (93,8%) of the LPVs.

Conclusions

the present study, assessing a novel, personalized protocol for radiofrequency titration during atrial fibrillation ablation, shows a high rate of first pass isolation with a lower need for RF energy delivery and lower procedure requirements, as compared to previous PV ablation protocols. Further studies are needed to evaluate the long-term results of this approach.

Abstract Figure. LAWT-map Visitag points with tailored AI

659Left atrial wall thickness evaluation during atrial fibrillation redo procedures

Funding Acknowledgements

Dr Teres was funded by Swiss Heartrhythm Foundation

Introduction

pulmonary vein (PV) reconnections due to gaps on circumferential ablation lines are responsible for atrial fibrillation recurrences after catheter ablation. We sought to analyze the local left atrial wall thickness (LAWT) of PV line gaps at AF redo ablation during real-time catheter positioning. LAWT was measured on the MDCT 3D reconstruction and fused with the LA anatomy using CARTO-merge.

Objective

To analyze the relationship between local reconnection gaps and the LAWT during AF redo procedures.

Methods

Single-Center cohort study that included 41 consecutive patients referred for AF redo procedure. All patients had a MDCT prior to the ablation procedure. LAWT maps were semi-automatically computed from the MDCT as the local distance between the LA endo and epicardium. Each PV line was subdivided into 8 segments and mean LAWT was computed. During the procedure, the local gap was defined as the earliest activation site at the reconnected segment of the circumferential PV line (Figure 1A & 1B).

Results

41 patients [31 (75.6%) male, age 60 ± 10 years] were included. Mean LAWT was 1.36 ± 0.20 mm. Mean PV circumferential line WT was higher in left PVs than in the right PVs 1.68 ± 0.57 vs. 1.31 ± 0.39 mm p &lt; 0.001 respectively. Mean WT of the reconnected points was 44% higher than the mean WT of the segment where the reconnection was located. Mean reconnection point WT was at the 87th percentile of the circumferential line in the LPVs and at the 76th percentile in the RPVs. The reconnected point WT was higher in the LPVs than RPVs 2.13 ± 1.14 vs. 1.47 ± 0.48 mm p &lt; 0.001 respectively.  The most frequent location for reconnections was the left anterior carina (71%), with a mean WT of 2.24 ± 0.91mm; and the right anterior carina (56%) with a mean WT of 1.57 ± 0.62mm (Figure 2A & 2B).

Conclusions

Reconnection points were more frequently present in the thicker segments of the PV circumferential line. The most frequently reconnected segment was the anterior carina in both right and left PVs. Atrial wall thickness maps derived from MDCT are useful to guide AF redo procedures.

Abstract Figure. 1) Activation & WT map; 2) Segment WT

P1106Fundamental differences and predictors of scar arrhythmogenicity in ischemic patients using cardiac magnetic resonance: a propensity score-matching study

Introduction

 Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) permits to identify the arrhythmogenic substrate (AS) in ischemic patients. However, it is unknown why the majority of them never develop ventricular tachycardias (VT), irrespectively of their left ventricular ejection fraction (LVEF). 

Purpose

 To characterize the fundamental differences and potential predictors of scar arrhythmogenicity in post-myocardial infarction (MI) patients with and without VT.

Methods

 36 consecutive ischemic patients with no arrhythmia evidence underwent a LGE-CMR study 4 years after the MI (controls). Scar data were compared with those obtained from 49 ischemic patients referred for VT substrate ablation (cases). Propensity score matching (PSM) was performed to adjust for age, LVEF, scar mass, and time from MI. The myocardium was segmented in 10 layers (endo- to epicardium), characterizing the core, border zone (BZ) and BZ channels (BZCs) using a dedicated post-processing software.

Results

 Compared to controls, cases were significantly older (67.3 ± 9.1 vs. 56.5 ± 11), had lower LVEF (33.1 ± 10.1 vs. 51 ± 9.4), greater scar mass (33.9 ± 17.2 vs. 14.2 ± 11.6 g), BZ mass (21.1 ± 9.9 vs. 9.6 ± 7.6 g), core mas (12.6 ± 8.8 vs. ± g), number of BZC (2.9 ± 1.4 vs. 1.1 ± 1.1) and BZC mass (10.5 ± 4.2 vs. 2.3 ± 2.4 g) (p &lt; 0.001 in all cases). After PSM (2:1) adjustment[BJG1] , cases had more BZCs (2.9 ± 1.4 vs. 2.2 ± 0.6; p = 0.01) and a greater BZC mass (10.5 ± 4.2 vs. 4.6 ± 2.6 g; p &lt; 0.001). In the multivariable logistic regression analysis, the BZC mass was the only independent predictor of being a case [OR 2.3 (1.5–3.4); p &lt; 0.001]. Receiver operating characteristic curve analysis identified a cut-off point of BZC mass &gt;4.28 g (AUC 0.98; p &lt; 0.001), showing 100% sensitivity and 91% specificity for cases’ discrimination.

Conclusions

 Compared with the cases, an otherwise similar control group (PS-matched for age, LVEF, scar mass, and time from MI) showed fewer BZC and a reduced BZC mass. BZC mass was the only independent predictor of being a case. A BZC mass cut-off point of &gt; 4.28 g showed a 100% sensitivity and 91% specificity for the identification of ischemic patients with documented VT.

Abstract Figure. Mean BZC mass and ROC curve analysis

125Manual vs. automatic local activation time annotation for guiding premature ventricular complex ablation procedures (MANIaC - PVC study)

Funding Acknowledgements

Financial support was provided in form of a research grant from Biosense Webster

Introduction

 The use of an algorithmic method (wavefront, WF) based on automatic annotation of the maximal negative slope of the unipolar electrogram (uni-EGM) within the window demarcated by the bipolar EGM (bi-EGM) may accurately identify the earliest activation site (EAS) during premature ventricular complex (PVC) ablation procedures.

Purpose

 To assess the potential benefits of a local activation time (LAT) automatic acquisition protocol using WF plus an automatic algorithm for ECG pattern matching recognition (AUT-arm) instead of a manual LAT annotation plus ECG visual inspection (MAN-arm) during premature ventricular complexes (PVCs) ablation procedures.

Methods

 Prospective, randomized, controlled and international multicenter study (NCT03340922). 69 consecutive patients with indication for PVC ablation were enrolled and randomized to AUT (n = 34) or MAN (n = 35) annotation protocols using the CARTO3 navigation system. The primary endpoint was mapping success, defined as complete PVC abolition after a maximum of 2 radiofrequency (RF) applications or up to 90 seconds at the identified EAS, considered the site of origin (SOO). Complete PVC abolition was considered as the procedure success, whereas clinical success was defined as the PVC-burden reduction of &gt;80% in the 24-h Holter at least 1 month after the procedure. Concordance analysis of the maps obtained with both methods was performed.

Results

 Mean age was 69 ± 15, 58% men. The mean baseline PVC burden was 26 ± 13%, mean LVEF 55 ± 12%. Baseline characteristics were similar between groups. The most frequent PVC-SOO were RVOT (41%), LV (25%; being the summit the most frequent location), and LVOT (16%), with no MAN-AUT differences. Total mapping time, number of RF applications, RF time, and procedure time were similar for both groups. The AUT-arm had a higher number of mapping points acquired (164 vs. 61; p = 0.002). There was a delayed detection of LAT at the EAS in the AUT-arm (mean 23 ± 13 ms), being more significant in left-sided PVCs (30 ± 12 vs. 15 ± 9 ms, p &lt; 0.001). The 10-ms isochronal area was significantly bigger in the MAN-arm (1.95 ± 2.7 vs. 1.0 ± 1.0; p = 0.05). The median (interquartile range) distance between AUT-EAS and MAN-EAS was 4 (0–6.8) mm. Mapping success was similar for AUT (65%) and MAN (63%) (p = 1.0). Procedure success was significantly better for the AUT-arm (100% AUT vs. 86% MAN; p = 0.04), but without differences in clinical success (87% AUT vs. 82% MAN; p = 0.7). There were no procedure-related complications.

Conclusions

 The use of a complete automatic protocol for LAT annotation (WF + ECG pattern matching) during PVC ablation procedures is feasible and safe, allowing to achieve equivalent procedural and clinical endpoints as compared to manual procedures carried out by expert operators.

Influence of baseline QRS on the left ventricular ejection fraction recovery after frequent premature ventricular complex ablation

Aims

Frequent premature ventricular complexes (PVCs) can induce or worsen left ventricular systolic dysfunction. We aimed to investigate the influence of the baseline QRS in the response after PVC ablation in patients with depressed left ventricular ejection fraction (LVEF).

Methods and results

Two hundred and fifteen [59 ± 13 years old, 152 (71%) men] consecutive patients with left ventricular (LV) systolic dysfunction and frequent PVCs referred for ablation were included and followed-up for 12 months. Echocardiographic response was defined as an improvement of at least five absolute points in LVEF. Clinical, electrocardiogram, and electrophysiological characteristics were analysed. Mean baseline QRS duration was 110 ms [97–140]. Premature ventricular complex burden significantly decreased after ablation from 23% [16–33] at baseline to 1% [0–8] at 12 months, P &lt; 0.001. Mean PVC burden reduction was 18 [8–30] points. There was a significant improvement of LVEF from 35% [29–40] at baseline to 44% [35–55] at 12 months, P &lt; 0.001. One hundred and thirty (61%) patients were considered as echocardiographic responders. Baseline QRS duration (ms) [odds ratio (OR) 0.98 (0.97–0.99), P = 0.01] was an independent predictor of echocardiographic response. Mean LVEF improvement was 16 [10–21] points when the baseline QRS duration was &lt;90 ms; 12 [4–20] when it was 90–110 ms; 5 [0–15] when it was 110 ± 130 ms; and 0 [0–6] points when it was &gt;130 ms.

Conclusions

In patients with LV systolic dysfunction, intrinsic QRS duration is inversely related to the probability and the degree of echocardiographic response after frequent PVC ablation. Patients with a QRS duration &gt;130 ms at baseline have the poorer response after ablation.

3255Characterization of the arrhythmogenic substrate with multimodality imaging in ischemic patients undergoing VT ablation: relationship between cardiac computed tomography and magnetic resonance

Background

Cardiac magnetic resonance (CMR)-aided ventricular tachycardia (VT) substrate ablation has shown to improve VT recurrence-free survival, through a better identification of the arrhythmogenic substrate. However, the access to CMR may be limited in certain centers or sometimes Its use can be contraindicated in patients with cardiac implantable electronic device. Cardiac computed tomography (CT) has shown to improve the results of substrate ablation, correlating with low-voltage areas and local abnormal ventricular activity, and identifying ridges of myocardial tissue (CT-channels) that may be appropriate target sites for ablation.

Purpose

To evaluate the correlation between CT and CMR imaging in identifying anatomical heterogeneous tissue channels (CMR-channels) or CT-channels in ischemic patients undergoing VT substrate ablation.

Methods

The study included 30 post-myocardial infarction (MI) patients (mean age 69±10; 94% male, left ventricular ejection fraction 35±10%), who underwent both CMR and cardiac CT before VT substrate ablation. Using a dedicated post-processing software, the myocardium was segmented in 10 layers from endocardium to epicardium both for the CMR and CT, characterizing the presence of CMR-channels and CT-channels, respectively, by two blinded operators, assigned either to CMR or CT analysis. CMR-channels were classified as endocardial (CMR-channels in layer <50%), epicardial (CMR-channels in layers ≥50%) or transmural (in both endo and epicardial layers). Presence and location of CT and CMR-channels were compared.

Results

In 26/30 patients (86.7%) 91 CT-channels (mean 3.0±1.9 per patient) were identified while 30/30 (100%) showed CMR-channels (n=76; mean 2.4±1.2 per patient). We found 190 CT-channel entrances (mean 6.3±4.1 per patient), and 275 CMR-channel entrances (mean 8.9±4.9 per patient) on cardiac CT and CMR, respectively. There were 47/91 (51.6%) true positive CT-channels. On the contrary, 44/91 (48.4%) CT-channels were considered false positives [19/91 (20.9%) identified out of CMR scar], and 29/76 (38.2%) CMR-channels could not be identified on CT. Thirty-six out of 76 (47.4%) CMR-channels were considered as non-endocardial (epi- or transmural). Twenty-nine out of 36 (80.5%) non-endocardial CMR-channels were coincident with CT-channels.

CT and CMR Channels

Conclusion

CT shows a modest sensitivity in identifying CMR-channels and fails in ascertain their complexity, underestimating the number of entrances; however, channels location at CT fit well with CMR for those classified as transmural or epicardial.

Mortality and morbidity reduction after frequent premature ventricular complexes ablation in patients with left ventricular systolic dysfunction

Aims

Ablation of frequent premature ventricular complexes (PVCs) improves left ventricular ejection fraction in patients with left ventricular (LV) systolic dysfunction. This study aims to evaluate the long-term hard outcomes and potential prognostic variables in this population.

Methods and results

Prospective multicentre study including 101 consecutive patients [56 ± 12 years old, 62 (61%) men] with LV systolic dysfunction and frequent PVCs who underwent PVC ablation before November 2015. The last evaluation performed was considered the long-term follow-up (LTFUP) evaluation. Mean follow-up was 34 ± 16 months (range 24–84 months). Ablation was successful in 95 (94%) patients. There was a significant reduction in the PVC burden from 21 ± 12% at baseline to 3.8 ± 6% at LTFUP, P < 0.001. Left ventricular ejection fraction improved from 32 ± 8% at baseline to 39 ± 12% at LTFUP (P < 0.001) and New York Heart Association class from 2.2 ± 0.6% to 1.3 ± 0.6% (P < 0.001). Brain natriuretic peptide levels decreased from 136 (78–321) to 68 (32–144) pg/mL (P = 0.007). Most of this improvement occurs during the first 6 months after ablation. Persistent abolition of at least 18 points of the baseline PVC burden was independently and inversely associated with the composite endpoint of cardiac mortality, cardiac transplantation, or hospitalization for heart failure during follow-up [hazard ratio 0.18 (0.05–0.66), P = 0.01].

Conclusion

In patients with LV systolic dysfunction, ablation of frequent PVCs induces a significant improvement in functional, structural, and neurohormonal status, which persists at LTFUP. A sustained reduction in the baseline PVC burden is associated with a lower risk of cardiac mortality, cardiac transplantation, or hospitalization for heart failure during follow-up.

[New diagnostic tools for arrhythmias]

Cardiac arrhythmias are common conditions that often manifest themselves intermittently, thus complicating their diagnosis, particularly in the ambulatory setting. Recently, technological advances have facilitated public access to health applications and devices. This article reviews the available technologies and analyses their usefulness for the diagnosis of arrhythmias in the context of everyday clinical practice.