Patient characteristics, predictors and outcome of pacemaker patients upgraded to an implantable cardioverter defibrillator

AIMS

Pacemaker (PM) patients may require a subsequent upgrade to an implantable cardioverter defibrillator (ICD). Limited data exists on this patient population. We sought to characterize this population, to assess predictors for ICD upgrade, and to report the outcome.

METHODS

From our prospective PM and ICD implantation registry, all patients who underwent PM and/or ICD implantations at our center were analyzed. Patient characteristics and outcomes of PM patients with subsequent ICD upgrade were compared to age- and sex-matched patients with de novo ICD implantation, and to PM patients without subsequent upgrade.

RESULTS

Of 1'301 ICD implantations, 60 (5%) were upgraded from PMs. Median time from PM implantation to ICD upgrade was 2.6 years (IQR 1.3-5.4). Of 2'195 PM patients, 28 patients underwent subsequent ICD upgrades, corresponding to an estimated annual incidence of an ICD upgrade of at least 0.33%. Lower LVEF (p = .05) and male sex (p = .038) were independent predictors for ICD upgrade. Survival without death, transplant and LVAD implantation were worse both for upgraded ICD patients compared to matched patients with de novo ICD implantation (p = .05), as well as for PM patients with subsequent upgrade compared to matched PM patients not requiring an upgrade (p = .036).

CONCLUSIONS

One of 20 ICD implantations are upgrade of patients with a PM. At least one of 30 PM patients will require an ICD upgrade in the following 10 years. Predictors for ICD upgrade are male sex and lower LVEF at PM implantation. Upgraded patients have worse outcomes.

Durability of CLOSE-Guided Pulmonary Vein Isolation in Persistent Atrial Fibrillation: A Prospective Remapping Study

BACKGROUND

Recurrence of paroxysmal atrial fibrillation (AF) following pulmonary vein isolation (PVI) is presumably caused by pulmonary vein (PV) reconnections. However, there is little data available on the durability of PVI and incidence of arrhythmia recurrence in patients with persistent AF.

OBJECTIVES

To evaluate the lesion durability by means of an a priori planned remapping procedure in patients with persistent AF undergoing CLOSE-guided PVI.

METHODS

In a prospective study, we included patients with symptomatic, persistent AF undergoing CLOSE-guided radiofrequency ablation. Irrespective of AF recurrence, a redo procedure was mandated 6 months following the index procedure to evaluate PV reconnections. The outcome of AF ablation was based on clinical recurrence and 7-day Holter electrocardiogram 3 and 6 months after the index procedure and 3, 6, and 12 months after the redo procedure.

RESULTS

Of 30 patients included, 26 (81% men; median age 68 years) underwent the planned remapping study a median of 6 months after the index procedure, whereas 4 patients without recurrence refused a repeat procedure. In total, 78 of 102 (76%) PVs showed durable isolation and 15 patients (58%) presented complete isolation of all PVs. Beyond the blanking period, 6 of 26 patients (23%) had arrhythmia recurrence before the redo procedure. Recurrence had occurred in 33% of patients with complete isolation of all veins and in 9% of patients with PV reconnections (P = 0.197). After re-PVI in patients with PV reconnections and additional ablation in patients with recurrence but durable PVI, 17 of 26 patients (65%) were free of arrhythmia after 12 months.

CONCLUSIONS

In patients with persistent AF, CLOSE-guided PVI resulted in durable rate of PVI on a per-vein and per-patient level of 76% and 58%, respectively. Arrhythmia recurrence was numerically higher in patients with durable PVI compared with patients without.

Validation of a clinical model for predicting left versus right ventricular outflow tract origin of idiopathic ventricular arrhythmias

BACKGROUND

Prediction of the chamber of origin in patients with outflow tract ventricular arrhythmias (OTVA) remains challenging. A clinical risk score based on age, sex and presence of hypertension was associated with a left ventricular outflow tract (LVOT) origin. We aimed to validate this clinical score to predict an LVOT origin in patients with OTVA.

METHODS

In a two-center observational cohort study, unselected patients undergoing catheter ablation (CA) for OTVA were enrolled. All procedures were performed using an electroanatomical mapping system. Successful ablation was defined as a ≥80% reduction of the initial overall PVC burden after 3 months of follow-up. Patients with unsuccessful ablation were excluded from this analysis.

RESULTS

We included 187 consecutive patients with successful CA of idiopathic OTVA. Mean age was 52 ± 15 years, 102 patients (55%) were female, and 74 (40%) suffered from hypertension. A LVOT origin was found in 64 patients (34%). A score incorporating age, sex and presence of hypertension reached 73% sensitivity and 67% specificity for a low (0-1) and high (2-3) score, to predict an LVOT origin. The combination of one ECG algorithm (V2 S/V3 R-index) with the clinical score resulted in a sensitivity and specificity of 81% and 70% for PVCs with R/S transition at V3 .

CONCLUSION

The published clinical score yielded a lower sensitivity and specificity in our cohort. However, for PVCs with R/S transition at V3, the combination with an existing ECG algorithm can improve the predictability of LVOT origin.

Pulsed-field ablation for the treatment of left atrial reentry tachycardia

BACKGROUND

We describe our initial experience using a multipolar pulsed-field ablation catheter for the treatment of left atrial (LA) reentry tachycardia.

METHODS

We included all patients with LA reentry tachycardia treated with PFA at our institution between September 2021 and March 2022. The tachycardia mechanism was identified using 3D electro-anatomical mapping (3D-EAM). Subsequently, a roof line, anterior line, or mitral isthmus line was ablated as appropriate. Roof line ablation was always combined with LA posterior wall (LAPW) ablation. Positioning of the PFA catheter was guided by a 3D-EAM system and by fluoroscopy. Bidirectional block across lines was verified using standard criteria. Additional radiofrequency ablation (RFA) was used to achieve bidirectional block as necessary.

RESULTS

Among 22 patients (median age 70 (59-75) years; 9 females), we identified 27 LA reentry tachycardia: seven roof dependent macro-reentries, one posterior-wall micro-reentry, twelve peri-mitral macro-reentries, and seven anterior-wall micro-reentries. We ablated a total of 20 roof lines, 13 anterior lines, and 6 mitral isthmus lines. Additional RFA was necessary for two anterior lines (15%) and three mitral isthmus lines (50%). Bidirectional block was achieved across all roof lines, 92% of anterior lines, and 83% of mitral isthmus lines. We observed no acute procedural complications.

CONCLUSION

Ablation of a roof line and of the LAPW is feasible, effective, and safe using this multipolar PFA catheter. However, the catheter is less suited for ablation of the mitral isthmus and the anterior line. A focal pulsed-field ablation catheter may be more effective for ablation of these lines. This study shows the feasibility to ablate linear lesions with a multipolar pulsed-field ablation catheter. 27 left atrial reentry tachycardia were treated in 22 patients.

Acute and Long-term Outcomes of quadripolar IS-4 versus bipolar IS-1 Left Ventricular Leads in Cardiac Resynchronization Therapy: A Retrospective Registry Study

BACKGROUND

The implantation procedure of left ventricular (LV) leads and the management of cardiac resynchronization therapy (CRT) patients can be challenging. The IS-4 standard for CRT offers additional pacing vectors compared to bipolar leads (IS-1). IS-4 leads improve procedural outcome and may also result in lower adverse events during follow-up (FU) and improve clinical outcome in CRT patients. Further long-term FU data comparing the two lead designs are necessary.

METHODS

In this retrospective, single-center study we included adult patients implanted with a CRT-Defibrillator (CRT-D) or CRT-Pacemaker (CRT-P) with a quadripolar (IS-4 group) or bipolar (IS-1 group) LV lead and with available ≥3 years clinical FU. The combined primary endpoint was a combination of predefined, lead-related adverse events. Secondary endpoints were all single components of the primary endpoint.

RESULTS

Overall, 133 patients (IS-4 n = 66; IS-1 n = 67) with a mean FU of 4.03±1.93 years were included. Lead-related adverse events were less frequent in patients with an IS-4 lead than with an IS-1 lead (n = 8, 12.1% vs. n = 23, 34.3%; p = 0.002). The secondary outcomes showed a lower rate of LV lead deactivation/explantation and LV lead dislodgement/dysfunction (4.5% vs 22.4%; p = 0.003; 4.5% vs. 17.9%; p = 0.015, respectively) in the IS-4 patient group. Less patients suffered from unresolved phrenic nerve stimulation with an IS-4 lead (3.0% vs. 13.4%; p = 0.029). LV lead-related re-interventions were fewer in case of an IS-4 lead (6.1% vs. 17.9%; p = 0.036).

CONCLUSION

In this retrospective analysis, the IS-4 LV lead is associated with lower lead-related complication rates than the IS-1 lead at long-term FU. This article is protected by copyright. All rights reserved.

Validation of the accuracy of contact force measurement by contemporary force-sensing ablation catheters

INTRODUCTION

Contact force sensing catheters are widely used for ablation of cardiac arrhythmias. They allow quantification of catheter-to-tissue contact, which is an important determinant for lesion formation and may reduce the risk of complications. The accuracy of these sensors may vary across the measurement range, catheter-to-tissue angle, and amongst manufacturers. We aim to compare the accuracy and reproducibility of four different force sensing ablation catheters.

METHODS

A measurement setup containing a heated saline water bath with an integrated force measurement unit was constructed and validated. Subsequently, we investigated four different catheter models, each equipped with a unique measurement technology: Tacticath Quartz (Abbott), AcQBlate Force (Biotronik/Acutus), Stablepoint (Boston Scientific), and Smarttouch SF (Biosense Webster). For each model, the accuracy of three different catheters was measured within the range of 0-60 g and at contact angles of 0°, 30°, 45°, 60°, and 90°.

RESULTS

In total, 6685 measurements were performed using 4 × 3 catheters (median of 568, interquartile range: 511-606 measurements per catheter). Over the entire measurement-range, the force measured by the catheters deviated from the real force by the following absolute mean values: Tacticath 1.29 ± 0.99 g, AcQBlate Force 2.87 ± 2.37 g, Stablepoint 1.38 ± 1.29 g, and Smarttouch 2.26 ± 2.70 g. For some models, significant under- and overestimation of >10 g were observed at higher forces. Mean absolute errors of all models across the range of 10-40 g were <3 g.

CONCLUSION

Contact measured by force-sensing catheters is accurate with 1-3 g deviation within the range of 10-40 g. Significant errors can occur at higher forces with potential clinical consequences.

Efficacy and safety of a novel cryoballoon ablation system: multicentre comparison of 1-year outcome

AIMS

The aim of the study was to compare the 1-year efficacy and safety of a novel cryoballoon (NCB) ablation system (POLARx; Boston Scientific) for pulmonary vein isolation (PVI) compared with the standard cryoballoon (SCB) system (Arctic Front, Medtronic).

METHODS AND RESULTS

Consecutive patients with atrial fibrillation (AF) undergoing PVI using the NCB and the SCB at two centres were included. We report 1-year efficacy after 12 months, short-term safety and hospitalizations within the blanking period, and predictors for AF recurrence. In case of repeat procedures, pulmonary vein (PV) reconnection patterns were characterized. Eighty patients (age 66 ± 10 years, ejection fraction 57 ± 10%, left atrial volume index 39 ± 13 mL/m2, paroxysmal AF in 64%) were studied. After a single procedure and a follow-up of 12 months, 68% in the NCB group and 70% in the SCB group showed no recurrence of AF/atrial tachycardias (P = 0.422). One patient in the NCB group suffered a periprocedural stroke with full recovery. There were no differences regarding hospitalizations during follow-up between the groups. PV reconnection observed during 12 repeat procedures (4 NCB, 8 SCB) pattern was comparable between the groups with more reconnections in the right-sided compared with the left-sided PVs.

CONCLUSION

In this multicentre study comparing two currently available cryoballoon ablation systems for PVI, no differences were observed in the efficacy and safety during a follow-up of 12 months.

Clinical Outcomes in Patients With Dilated Cardiomyopathy and Ventricular Tachycardia

BACKGROUND

Recurrent ventricular tachycardia (VT) due to dilated cardiomyopathy (DCM) is difficult to treat, and long-term outcome data are limited.

OBJECTIVES

The aim of this study was to identify predictors of mortality or heart transplantation (HTx) and VT recurrence.

METHODS

Consecutive patients with DCM accepted for radiofrequency catheter ablation (RFCA) of VT at 9 centers were prospectively enrolled and followed.

RESULTS

Of 281 consecutive patients (mean age 60 ± 13 years, 85% men, mean left ventricular ejection fraction [LVEF] 36% ± 12%), 35% had VT storm, 20% had incessant VT, and amiodarone was unsuccessful in 68%. During follow-up of 21 months (IQR: 6-30 months), 67 patients (24%) died or underwent HTx, and 138 (49%) had VT recurrence (45 within 30 days, defined as early); the 4-year rate of VT recurrence or mortality or HTx was 70%. Independent predictors of mortality or HTx were early VT recurrence (HR: 2.92; 95% CI: 1.37-6.21; P < 0.01), amiodarone at discharge (HR: 3.23; 95% CI: 1.43-7.33; P < 0.01), renal dysfunction (HR: 1.92; 95% CI: 1.01-3.64; P = 0.046), and LVEF (HR: 1.36; 95% CI: 1.0-1.84; P = 0.052). LVEF ≤32% identified patients at risk for mortality or HTx (area under the curve: 0.75). Mortality or HTx per 100 person-years was 40.4 events after early, compared with 14.2 events after later VT recurrence and 8.5 events with no VT recurrence after RFCA (P < 0.01 for both). Patients with early recurrence and LVEFs ≤32% had a 1-year rate of mortality or HTx of 55%. VT recurrence was predicted by prior implantable cardioverter-defibrillator shocks, basal anteroseptal VT origin, and procedural failure but not LVEF.

CONCLUSIONS

Patients with DCM needing RFCA for VT are a high-risk group. Following RFCA, approximately one-half remain free of VT recurrence. Early VT recurrence with LVEF ≤32% identifies those at very high risk for mortality or HTx, and screening for mechanical support or HTx should be considered. Late VT recurrence after RFCA does not predict worse outcome.

Validation of a multipolar pulsed-field ablation catheter for endpoint assessment in pulmonary vein isolation procedures

AIMS

To validate the performance of a multipolar pulsed-field ablation (PFA) catheter compared to a standard pentaspline 3D-mapping catheter for endpoint assessment of pulmonary vein isolation (PVI). PFA for PVI using single-shot devices combines the benefits of high procedural efficacy and safety. A newly available multipolar PFA catheter allows real-time recording of pulmonary vein (PV) signals during PVI.

METHODS AND RESULTS

Patients undergoing first PVI using PFA with the standard ablation protocol (eight applications per PV) were studied. Entrance and exit block (10 V/2 ms) were assessed using the PFA catheter. Subsequently, a high-density 3D electroanatomical bipolar voltage map (3D-EAM) was constructed using a standard pentaspline 3D-mapping catheter. Additional PFA applications were delivered only after confirmation of residual PV connection by 3D-EAM. In 56 patients, 213 PVs were targeted for ablation. Acute PVI was achieved in 100% of PVs: in 199/213 (93%) PVs with the standard ablation protocol alone and in the remaining 14 PVs after additional PFA applications. The accuracy of PV assessment with the PFA catheter after the standard ablation protocol was 91% (194/213 veins). In 5/213 (2.3%) PVs, the PFA catheter incorrectly indicated PV-isolation. In 14/213 (6.6%), the PFA catheter incorrectly indicated residual PV-conduction due to high-output pace-capture. Lowering the output to 5 V/1 ms reduced this observation to 0.9% (2/213) and increased the overall accuracy to 97% (206/213).

CONCLUSION

A novel multipolar PFA catheter allows reliable endpoint assessment for PVI. Due to its design, far-field sensing and high-output pace-capture can occur. Lowering the pacing output increases the accuracy from 91 to 97%.

Evolution of tricuspid valve regurgitation after implantation of a leadless pacemaker - a single center experience, systematic review and meta-analysis

Introduction

Conventional transvenous pacemaker leads may interfere with the tricuspid valve leaflets, tendinous chords, and papillary muscles, resulting in significant tricuspid valve regurgitation (TR). Leadless pacemakers (LLPMs) theoretically cause less mechanical interference with the tricuspid valve apparatus. However, data on TR after LLPM implantation are sparse and conflicting. Our goal was to investigate the prevalence of significant TR before and after LLPM implantation.

Methods

Patients who received a leadless LLPM (Micra™ TPS, Medtronic) between May 2016 and May 2021 at our center were included in this observational study if they had at least a pre‐ and postinterventional echocardiogram (TTE). The evolution of TR severity was assessed. Following a systematic literature review on TR evolution after implantation of a LLPM, data were pooled in a random‐effects meta‐analysis.

Results

We included 69 patients (median age 78 years [interquartile range (IQR) 72–84 years], 26% women). Follow‐up duration between baseline and follow‐up TTE was 11.4 months (IQR 3.5–20.1 months). At follow‐up, overall TR severity was not different compared to baseline (p = .49). Six patients (9%) had new significant TR during follow‐up after LLPM implantation, whereas TR severity improved in seven patients (10%). In the systematic review, we identified seven additional articles that investigated the prevalence of significant TR after LLPM implantation. The meta‐analysis based on 297 patients failed to show a difference in significant TR before and after LLPM implantation (risk ratio 1.22, 95% confidence interval 0.97–1.53, p = .11).

Conclusion

To date, there is no substantial evidence for a significant change in TR after implantation of a LLPM.

Gender gap in study inclusion: Insights from the STAR-FIB cohort study

Funding Acknowledgements

Type of funding sources: Foundation. Main funding source(s): Swiss National Science Foundation Swiss Heart Foundation

Background

The underrepresentation of women in cardiovascular clinical trials is well described but cannot be fully explained by sex-specific differences in the prevalence of cardiovascular diseases. Data on potential sex- and gender-related differences in study exclusion reasons are scarce.

The STAR-FIB cohort study aimed to estimate the age and sex-specific prevalence of screening-detected atrial fibrillation (AF) in 800 hospitalized patients aged 65-84 years using serial seven-day ECGs. Recruitment for study inclusion was stratified by sex (female/male, as stated in the patient’s records) and age (four age bands, ≥65 to &lt;70, ≥70 to &lt;75, ≥75 to &lt;80, and ≥80 to &lt;85 years), and was truncated for each subgroup after the inclusion of 100 participants.

Purpose

To assess sex and gender differences in patient recruitment for inclusion in the STAR-FIB cohort study.

Methods

A screening log containing sex-category, age, and reasons for exclusion was maintained. Exclusion criteria are shown in the figure. For the purpose of the present study, an explorative analysis of all exclusion criteria with respect to sex category was done.

Results

Overall, 11’470 patients were identified for eligibility, 795 patients (49% women; mean age 75 years) were enrolled, and 10’675 patients (52% women vs. 48% men, p =0.13) were not enrolled. The two major exclusion reasons were unwillingness to participate, which was more frequent in women (27.9% of women vs. 18.4% of men, p &lt; 0.01), and the presence of clinical AF, which was more prevalent in men (27.1% of men vs. 20.5 % of women, p &lt; 0.01). A detailed analysis of all exclusion criteria analysed by sex category is provided in the figure.

Conclusions

Clinical AF was more frequent in men, in accordance with the well described sex-driven (biological) higher prevalence of AF in men. In contrast, we found a higher percentage of women unwilling to participate in this study, which may represent a more gender-based (sociocultural) phenomenon. A further exploration of these findings should be performed and may help to identify and potentially overcome modifiable obstacles for study participation.

Pulsed field ablation of atrial fibrillation: recurrence rate after first pulmonary vein isolation and first insights into durability at redo procedures

Funding Acknowledgements

Type of funding sources: None.

Background

Pulsed field ablation (PFA) is newly available for pulmonary vein isolation (PVI) and combines the benefits of high procedural efficacy and safety. Independent data on the recurrence-rate of atrial fibrillation (AF) after PVI and on PVI durability during redo procedures are scarce.

Purpose

We report data on the recurrence rate of AF after first PVI using PFA and first insights into findings of PVI durability during redo procedures.

Methods

Consecutive AF patients undergoing a first PFA PVI at our center between May 2021 and August 2021 were included. PVI was verified by 3D-electroanatomical mapping (3D-EAM), and additional PFA lesions were applied when necessary until all PV were isolated. Seven-day Holter ECGs were performed at 3 and 6 months after ablation. After a blanking period of 3 months, episodes of AF/AT lasting more than 30 seconds were considered as AF-recurrence.

Results

41 Patients, median age 69 (interquartile range 62-73) years, 24% female, 56% persistent AF, underwent first PVI by PFA. All PVs were successfully isolated using a multipolar PFA catheter. Median total procedure time including 3D-EAM was 104 (85-121) min. Total fluoroscopy time and dose were 26 (19-30) min and 671 (323-1248) Gym2. Acute complications occurred in 1 (2.4%) patient (cardiac tamponade requiring drainage). Early recurrence of AF during the blanking period occurred in 1 (2.4%) patient. Median follow-up time was 107 (91-152) days. Recurrence of AF after the blanking period was detected in 5 (12%) patients, 1 (6%) in paroxysmal AF and 4 (17%) in persistent AF patients, respectively. Redo procedures in 3 (7.3%) patients with AF recurrence confirmed durable isolation of 12/12 (100%) pulmonary veins and showed no evidence of PFA lesion regression.

Conclusion

AF recurrence rates after PVI by means of PFA are low. Durable isolation of 12/12 pulmonary veins (100%) and no evidence of PFA lesion regression was observed during redo procedures in patients with AF recurrence.

Comparison of the accuracy of contact force measurement in four commercially available force-sensing ablation catheters

Funding Acknowledgements

Type of funding sources: None.

Background

Contact force-sensing catheters are widely used for ablation of cardiac arrhythmias. They allow precise quantification of catheter-to-tissue contact, which is an important determinant of lesion size and durability. Moreover, contact force information reduces the risk for cardiac perforation and is used for estimation of lesion size. However, the accuracy of contact force sensors across different manufacturers has not been validated independently.

Objective

To compare the accuracy and reproducibility of different force sensing catheters used in cardiac electrophysiology procedures.

Methods

A force measurement setup containing a heated saline water bath and a catheter fixation mechanism was constructed. The setup allows to accurately measure forces applied to a platform with the catheter. We studied four different catheter models, equipped with the following, unique force-measurement technologies (figure 1): 1) multiple-fiber optical sensor; 2) single-fiber optical sensor; 3) inductive sensor; and 4) magnetic field sensors. For each model, we assessed three catheters. Repeated measurements within the force range of 0g to 60g and at electrode-tissue contact angles of 0°, 45°, and 90° were performed and validated against the force measurement unit of our measurement setup.

Results

For each catheter, at least 500 measurements at different contact forces (equally distributed across the measurement range of 0 to 60 grams) were performed. Correlation of measured-force to real-force was ρSpearman=0.99 for MFOS, ρSpearman=0.98 for SFOS, ρSpearman=0.99 for IS, and ρSpearman=0.98 for MFS. MFS and SFOS showed a higher variance for high forces and increased intra-catheter variability compared to MFOS and IS. IS overestimated higher contact force at 0° and 30°. MFS and SFOS underestimated contact force for higher forces at 30° and 45° (figure 2). Within a clinical range of 5g to 40g, the catheters reached the following root-mean-square-error, independent of contact angle: MFOS 0.88g ±0.68g, SFOS 2.15g ±1.74g, IS 0.88g ±0.72g, and MFS 1.13g ±1.01g.

Conclusion

Measured contact by force-sensing catheters correlates well with true exerted electrode-tissue force. Despite an excellent overall correlation, some technologies may be prone to significant errors at higher forces (&gt;10g under-/overestimation of true contact force) with potential clinical consequences related to increased risk of perforation.

Validation of a multipolar pulsed field ablation catheter for endpoint assessment in pulmonary vein isolation procedures

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): FP7/2007-2013, №602299, EU-CERT-ICD

Objective

To validate the performance of a multipolar PFA catheter compared to a standard pentaspline 3D-mapping catheter for endpoint assessment of PVI.

Background

Pulsed field ablation (PFA) for pulmonary vein isolation (PVI) using single-shot devices combines the benefits of high procedural efficacy and safety. A newly available multipolar PFA catheter allows real-time recording of pulmonary vein (PV) signals during PVI.

Methods

Patients undergoing first PVI using PFA with the standard ablation protocol (8 applications per PV) were studied. Entrance- and exit-block (10V/2ms) were assessed using the PFA catheter. Subsequently, a high-density bipolar voltage 3D electro-anatomical map (3D-EAM) was constructed using a standard pentaspline 3D-mapping catheter. Additional PFA applications were delivered only after confirmation of residual PV-connection by 3D-EAM.

Results

In 56 patients, 213 PVs were targeted for ablation. Acute PVI was achieved in 100% of PVs: in 199/213 (93%) PVs with the standard ablation protocol alone and in the remaining 14 PVs after additional PFA applications. Accuracy of PV assessment with the PFA catheter after the standard ablation protocol was 91% (194/213 veins). In 5/213 (2.3%) PVs, the PFA catheter incorrectly indicated PV-isolation. In 14/213 (6.6%) the PFA catheter incorrectly indicated residual PV-conduction due to high-output pace-capture. When the output was reduced to 5V/1ms, pace-capture was reduced to 0.9% (2/213).

Conclusion

A novel multipolar PFA catheter allows reliable endpoint assessment for PVI. Due to its design, far-field sensing and high-output pace-capture can occur, which may require adjustment of standard pacing outputs for verification of exit-block.

Electrophysiological differences of deep sedation with dexmedetomidine versus propofol

Funding Acknowledgements

Type of funding sources: None.

Background

Dexmedetomidine and propofol are commonly used drugs for deep sedation during cardiovascular interventions. Patients undergoing these interventions often have impaired sinus node function or atrioventricular (AV) conduction disease. Anesthetics used for deep sedation may further compromise sinus node function and AV nodal conduction, and thereby interfere with the intervention.

Purpose

To compare the electrophysiological effects of dexmedetomidine and propofol on the function of the sinus node and AV conduction.

Methods

We randomized patients undergoing first atrial fibrilation ablation 1:1 to deep sedation by dexmedetomidine (DEX group) versus propofol (PRO group), according to a standardized protocol. At the end of the ablation procedure with the patients still deeply sedated and hemodynamically stable, we conducted a standard electrophysiological study and assessed sinus node function, properties of AV conduction and atrial refractoriness.

Results

Of 160 patients (65±11 years old; 32% female) included into the study, 80 patients were randomized to the DEX and PRO group each. Procedure duration (128±59 minutes) and sedation depth, as assessed by the "Modified Observer’s Assessment of Alertness/Sedation" score (median 3; interquartile range 2, 3), was not different among groups. DEX group patients received a mean of 231±111 mcg of dexmedetomidine and PRO group patients a mean of 657±356 mg of propofol. The table shows the results of the electrophysiological study. DEX group patients had lower sinus rate and longer unadjusted sinus node recovery time (SNRT) at pacing cycle lengths of 600, 500 and 400 ms. However, both corrected (SNRT-RR) and normalized (SNRT/RR) SNRT did not differ among groups. Compared to PRO group patients, AV nodal conduction was slower in DEX group patients as evidenced by longer PR and AH intervals, and a higher Wenckebach cycle length and AV node effective refractory period (ERP) was observed. Conduction properties in the His-Purkinje system were not different among groups, as QRS width and HV interval were similar. An arrhythmia, mainly atrial fibrillation, was induced in 33 patients (21%) during the electrophysiological study, without differences among groups.

Conclusions

Sinus rate and AV conduction are slower during deep sedation with dexmedetomidine compared to propofol. These differences in electrophysiological effects need to be taken into account when using these anesthetics during cardiovascular interventions.

Patient characteristics, predictors and outcome of pacemaker patients upgraded to an implantable cardioverter defibrillator

Funding Acknowledgements

Type of funding sources: None.

Introduction

Pacemaker (PM) patients may require a later upgrade to an implantable cardioverter-defibrillator (ICD). Limited data exists on this patient population. We sought to characterize this population, to assess predictors for ICD upgrade, and to report the outcome.

Methods

From our prospective PM and ICD implantation registry, all patients who underwent PM and/or ICD implantations at our center were analyzed. Patient characteristics and outcome of PM patients with subsequent ICD upgrade were compared to age- and sex-matched patients with de novo ICD implantation, and to PM patients without later upgrade.

Results

Of 1’301 ICD implantations, 60 (5%) were upgrades from PMs. Median time from PM implantation to ICD upgrade was 2.6 years (IQR 1.3-5.4) Of 2’195 PM patients, 28 patients underwent subsequent ICD upgrade, corresponding to an estimated annual incidence of an ICD upgrade of at least 0.33%. Lower LVEF (p=0.05) and male sex (p=0.038) were independent predictors for ICD upgrade. Transplant- and LVAD-free survival was worse both for upgraded ICD patients compared to matched patients with de novo ICD implantation (p=0.05; Figure, panel A), as well as for PM patients with later upgrade compared to matched PM patients not requiring an upgrade (p=0.036; Figure, panel B).

Conclusions

One of twenty ICD implantations are upgrades of patients with a PM. At least one of 30 PM patients will require an ICD upgrade in the following 10 years. Predictors for ICD upgrade are male sex and lower LVEF at PM implantation. Upgraded patients have worse outcome.

Diagnostic reliability of AV synchrony self-diagnostics in leadless VDD pacemakers

Funding Acknowledgements

Type of funding sources: None.

Introduction

Leadless pacemakers (PMs) capable of atrio-ventricular (AV) synchronous pacing have been introduced recently. These devices provide mechanical atrial sensing by detection of the atrial contraction via an accelerometer. Atrial tracking may be disturbed by external influences such as body motions and higher heart rates in real life. To track the amount of AV synchronous pacing, the device statistic classifies all sensed and paced QRS complexes according to presumed AV synchrony. The reliability of this self-diagnostics to estimate the true degree of AV synchrony, however, is insufficiently studied.

Purpose

To investigate the informative value of the device statistics offered by leadless VDD PMs regarding true AV snychrony.

Methods

We prospectively included all patients who received a leadless VDD PM between 07/2020 and 05/2021 at our center in this observational study. During the regular outpatient follow-ups, device interrogation was performed, which included evaluation of the PM statistics. True AV synchrony (defined as a QRS complex preceded by a p-wave within 300ms) was analyzed repeatedly during follow-up using Holter ECGs.

Results

We analysed 34 Holter ECGs from 20 outpatients (816 hours of ECG in total). Patients had a median age of 80 years (interquartile range 76-86 years), 55% were females. For Holter ECG sequences that showed high degree or complete AV-Block (&gt;80% ventricular pacing), the percentage of paced beats that were presumed to be AV synchronous by the device statistic (ratio "AM-VP"/total VP) correlated well with AV synchrony as assessed using Holter-ECGs (Kendall’s τ=0.312, p&lt;0.001). AV synchrony in the Holter ECG was different in patients with &lt;66.6% presumed AV synchrony than in patients with &gt;66.6% presumed AV synchrony (p&lt;0.001, figure). For Holter ECG sequences with mostly preserved intrinsic AV conduction (&lt;20% ventricular pacing), the ratio "AM-VP"/total VP was not predictive for true AV synchrony (Kendall’s τ=0.07, p=n.s.). In this situation, however, "VS only" (Kendall’s τ=0.110, p=0.005) correlated with true AV synchrony (due to AV conduction mode switch) and "VP only" showed an inverse correlation with AV synchrony (Kendall’s τ=-0.215, p&lt;0.001).

Conclusion

Leadless PMs provide device statistics that show a correlation with true AV synchrony. The clinical setting as well as the device programming (e.g. AV conduction mode switch) significantly influence the predictive value of the different parameters of the device’s statistics.

The outcome spectrum for Dilated Cardiomyopathy and Ventricular Tachycardia: results from the prospective, multicenter, DCM-VT ablation study

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): The study was partially supported by an investigator initiated grant from Biosense Webster (a Johnson & Johnson company)

Background

Recurrent sustained ventricular tachycardia (VT) due to nonischemic dilated cardiomyopathy (DCM) is difficult to treat and long-term outcome data are limited.

Objective

We aimed to identify predictors for mortality or heart transplantation (MHT) and VT recurrence.

Methods

Consecutive DCM patients accepted for VT catheter ablation (RFCA) in 9 centers were prospectively enrolled and followed.

Results

Of 281 consecutive patients (age 60±13yrs, 85% men, LVEF 36±12%) 35% had VT storm, 20% incessant VT, and 68% failed amiodarone. During a median follow-up of 21 (IQR 6-30) months after RFCA (epicardial in 58%, no RFCA due to inaccessible target in 6.4%), 67(24%) patients died/underwent HT and 138(49%) had VT recurrence (45 within 30 days defined as early); the cumulative 4-year rate of VT or MHT was 70% and of MHT 38%.

In multivariable analysis predictors of MHT were early VT recurrence (HR 2.92 (CI1.37-6.21), p&lt;0.01), amiodarone at discharge (HR 3.23 (CI1.43-7.33, p&lt;0.01), renal dysfunction (HR 1.92 (CI1.01-3.64), p=0.046), and LVEF (HR 1.36 (CI 1.0-1.84), p=0.052). A LVEF ≤32% was the optimal threshold to identify patients at risk for MHT (AUC 0.75).

MHT per 100 person-years was 40.4 after early VT recurrence and significantly higher, compared to 14.2 after later VT recurrence and to 8.5 after RFCA with no VT recurrence (both p&lt;0.01). Mortality rates for patients with VT recurrence after 30 days were not significantly higher than for patients with no VT recurrences

Patients with early recurrence and LVEF≤32% had a 1-year MHT rate of 55% (figure). VT recurrence was predicted by prior ICD shocks, basal antero-septal VT origin, and procedural failure but not LVEF.

Conclusion

DCM patients needing RFCA for VT are a high-risk group. Following RFCA half remain free of VT recurrences. Early VT recurrence with LVEF&lt;0.32 identifies those with a very high risk and screening for mechanical support/ HT should be considered. Late VT recurrence after RFCA does not predict worse outcome.

Durability of CLOSE-guided pulmonary vein isolation in persistent atrial fibrillation - First results from a prospective remapping study

Funding Acknowledgements

Type of funding sources: None.

Background

The CLOSE protocol for pulmonary vein isolation (CLOSE-PVI) combines ablation index and inter-lesion distance (≤6 mm) targets. CLOSE-PVI has been shown to result in high clinical success rates. Data on durability of PVI after CLOSE-PVI mainly derive from repeat procedures in paroxysmal atrial fibrillation (AF) patients with recurrent AF.

Purpose

We sought to assess the incidence of pulmonary vein (PV) reconnections during a staged redo procedure performed independently of AF recurrence 6 months after CLOSE-PVI in patients with persistent AF.

Methods

In this prospective, single-center study, patients with symptomatic persistent AF (EHRA score &gt;1) undergoing AF ablation were included. Close-PVI was performed during the index procedure. A blanking period of 3 months was applied. Seven-day Holter ECGs were performed at 3 and 6 months post ablation. All patients underwent a staged redo procedure including high-density voltage mapping of the left atrium at 6 months after the index procedure.

Results

Overall, 20 patients were included (median age: 68 years [IQR 63-71]; 20% women; median duration of persistent AF: 8 months [IQR 5-15]; median LAVI 45 ml/m2 [IQR 43-53]). All PVs were successfully isolated with CLOSE-PVI during the index procedure. Four patients (20%) had AF recurrence. The redo procedure was performed after a median of 6.1 months (IQR 5.6-7.3). Of 80 PVs, 71 (89%) were still isolated. No patient had a common ostium. Reconnections were observed in 3 left superior (15%), in one left inferior (5%), in one right superior (5%) and in 4 right inferior (20%) PVs. Fourteen patients (74%) had completely isolated PVs. Two of four patients with AF recurrence (50%) and 12 of 16 patients without AF recurrence (75%) had completely isolated PVs (p=0.33).

Conclusions

CLOSE-PVI achieves durable PVI after 6 months in the majority of patients with persistent AF. In half of persistent AF patients with recurrence after CLOSE-PVI, all PVs are still isolated. These patients may need adjunctive ablation.

Differences in Atrial Remodeling in Hypertrophic Cardiomyopathy Compared to Hypertensive Heart Disease and Athletes' Hearts

Background: Hypertrophic cardiomyopathy (HCM), hypertensive heart disease (HHD) and athletes’ heart share an increased prevalence of atrial fibrillation. Atrial cardiomyopathy in these patients may have different characteristics and help to distinguish these conditions. Methods: In this single-center study, we prospectively collected and analyzed electrocardiographic (12-lead ECG, signal-averaged ECG (SAECG), 24 h Holter ECG) and echocardiographic data in patients with HCM and HHD and in endurance athletes. Patients with atrial fibrillation were excluded. Results: We compared data of 27 patients with HCM (70% males, mean age 50 ± 14 years), 324 patients with HHD (52% males, mean age 75 ± 5.5 years), and 215 endurance athletes (72% males, mean age 42 ± 7.5 years). HCM patients had significantly longer filtered P-wave duration (153 ± 26 ms) and PR interval (191 ± 48 ms) compared to HHD patients (144 ± 16 ms, p = 0.012 and 178 ± 31, p = 0.034, respectively) and athletes (134 ± 14 ms, p = 0.001 and 165 ± 26 ms, both p < 0.001, respectively). HCM patients had a mean of 4.9 ± 16 premature atrial complexes per hour. Premature atrial complexes per hour were significantly more frequent in HHD patients (27 ± 86, p < 0.001), but not in athletes (2.7 ± 23, p = 0.639). Left atrial volume index (LAVI) was 43 ± 14 mL/m2 in HCM patients and significantly larger than age- and sex-corrected LAVI in HHD patients 30 ± 10 mL/m2; p < 0.001) and athletes (31 ± 9.5 mL/m2; p < 0.001). A borderline interventricular septum thickness ≥13 mm and ≤15 mm was found in 114 (35%) HHD patients, 12 (6%) athletes and 3 (11%) HCM patients. Conclusions: Structural and electrical atrial remodeling is more advanced in HCM patients compared to HHD patients and athletes.

Importance of electromagnetic interactions between ICD and VAD devices - mechanistic assessment

BACKGROUND

Implanted cardioverter defibrillators (ICD) and Left Ventricular Assist Devices (LVAD) are established interventions that prolong life in advanced heart failure, but their combination has not been demonstrated as beneficial. Electromagnetic interference (EMI) produced by a LVAD can preclude ICD interrogation with external programmers. We undertook a systematic evaluation of the LVAD-ICD interaction "in-vitro" to clarify the extent of this interaction.

METHODS

Using explanted ICDs and VADs in a mock physiological rig, we assessed interrogation and reprogramming of ICD devices in the presence of a running LVAD. When connectivity between the ICD programmer and the ICD failed, we attempted three different techniques to re-establish connectivity: (1) Electromagnetic shielding of the ICD with a pseudo-faraday cage; (2) altering the LVAD speed; (3) increasing the distance between the VAD and the ICD.

RESULTS

We tested a total of 24 ICDs from different manufacturers in the presence of the Heartware (HW) and HeartMate 3 (HM3) LVADs. With HW, we only observed interaction with Biotronik ICD-devices at very close range (0-6cm). With HM3, only Medtronic ICD devices showed no interaction. Interactions could be mitigated byincreasing the VAD-ICD distance.

CONCLUSIONS

LVADs, notably the HM3, produce EMI that interferes with the communication between an ICD and it's respective programmer. This may need to be considered when choosing the type of VAD to implant in patients with a previously implanted left-sided ICD. The only safe way to regain connectivity is to increase the distance between the VAD and the ICD, with patients raising their arm above their head.

Leadless atrio-ventricular synchronous pacing in an outpatient setting - early lessons learned on factors affecting atrio-ventricular synchrony

BACKGROUND

Leadless pacemakers (PMs) capable of atrio-ventricular (AV) synchronous pacing have recently been introduced. Initial feasibility studies were promising, but limited to just a few minutes of AV synchronous pacing. Real-world long-term data on AV synchrony and programming adjustments affecting AV synchrony in outpatients are lacking.

OBJECTIVE

To investigate AV synchrony and influences of PM programming adjustments in outpatients with leadless VDD PMs.

METHODS

All patients who received a leadless VDD PM (Micra™ AV, Medtronic, US) between 07/2020 and 05/2021 at our center were included in this observational study. AV synchrony was assessed repeatedly postoperatively and during follow-up using Holter ECG recordings. AV synchrony was defined as a QRS complex preceded by a p-wave within 300ms. The impact of programming changes during follow-up on AV synchrony was studied.

RESULTS

816 hours of Holter ECG from 20 outpatients were analyzed. During predominantly paced episodes (≥80% ventricular pacing), median AV synchrony was 91% (IQR 34-100%) when patients had sinus rates 50-80/min. Median AV synchrony was lower when patients had sinus rates >80/min (33%, IQR 29-46%, p<0.001). During a stepwise optimization protocol, AV synchrony could be improved (p<0.038). Multivariate analysis showed that a shorter maximum A3 window end (p<0.001), a lower A3 threshold (p=0.046), and minimum A4 threshold (p<0.001) improved AV synchrony.

CONCLUSION

Successful VDD pacing in the outpatient setting during higher sinus rates is more difficult to achieve than can be presumed based on the initial feasibility studies. The devices often require multiple reprogramming to maximize AV sequential pacing.

Dexmedetomidine versus Propofol for Operator-Directed Nurse-Administered Procedural Sedation during Catheter Ablation of Atrial Fibrillation: a Randomized Controlled Study

BACKGROUND

Operator-directed nurse-administered (ODNA) sedation with propofol is the preferred sedation technique for catheter ablation of atrial fibrillation (AF) in many centers.

OBJECTIVE

We aimed to investigate whether Dexmedetomidine, an α2-adrenergic receptor agonist, is superior to propofol.

METHODS

We randomized 160 consecutive patients undergoing first AF ablation to ODNA sedation by dexmedetomidine (DEX group) versus propofol (PRO group), according to a standardized protocol. Patients were unaware of treatment allocation. The primary endpoint was a composite of inefficient sedation, termination/change of sedation protocol or procedure abortion, hypercapnia (transcutaneous CO2 >55 mmHg), hypoxemia (SpO₂ <90%) or intubation, prolonged hypotension (systolic blood pressure <80 mmHg), and sustained bradycardia necessitating cardiac pacing. Secondary endpoints were the components of the primary endpoint and patient satisfaction with procedural sedation, as assessed by a standardized questionnaire the day following ablation.

RESULTS

The primary endpoint occurred in 15 DEX group and 25 PRO group patients (19% vs. 31%; p=0.068). Hypercapnia was significantly more frequent in PRO group patients (29% vs. 10%; p=0.003). There was no significant difference among the other components of the primary endpoint, no procedure was aborted. Patient satisfaction was significantly better in PRO group patients (visual analog scale 0-100; median 100 in PRO group vs. median 93 in DEX group; p<0.001).

CONCLUSION

Efficacy of ODNA sedation with dexmedetomidine was not different to propofol. Hypercapnia occurs less frequent with dexmedetomidine, but patient satisfaction is better with propofol sedation. In selected patients, dexmedetomidine may be used as an alternative to propofol for ODNA sedation during AF ablation. (ClinicalTrials.gov number NCT03844841).

Impact of contact force sensing technology on outcome of catheter ablation of idiopathic pre-mature ventricular contractions originating from the outflow tracts

AIMS

Catheter ablation of frequent idiopathic pre-mature ventricular contractions (PVC) is increasingly performed. While potential benefits of contact force (CF)-sensing technology for atrial fibrillation ablation have been assessed in several studies, the impact of CF-sensing on ventricular arrhythmia ablation remains unknown. This study aimed to compare outcomes of idiopathic outflow tract PVC ablation when using standard ablation catheters as opposed to CF-sensing catheters.

METHODS AND RESULTS

In a retrospective multi-centre study, unselected patients undergoing catheter ablation of idiopathic outflow tract PVCs between 2013 and 2016 were enrolled. All procedures were performed using irrigated-tip ablation catheters and a 3D electro-anatomical mapping system. Sustained ablation success was defined as a  ≥80% reduction of pre-procedural PVC burden determined by 24 h Holter ECG during follow-up. Overall, 218 patients were enrolled (median age 52 years, 51% males). Baseline and procedural data were similar in the standard ablation (24%) and the CF-sensing group (76%). Overall, the median PVC burden decreased from 21% (IQR 10-30%) before ablation to 0.2% (IQR 0-3.0%) after a median follow-up of 2.3 months (IQR 1.4-3.9 months). The rates of both acute (91% vs. 91%, P = 0.94) and sustained success (79% vs. 74%, P = 0.44) were similar in the standard ablation and the CF-sensing groups. No differences were observed in subgroups according to arrhythmia origin from the RVOT (65%) or LVOT (35%). Complications were rare (1.8%) and evenly distributed between the two groups.

CONCLUSION

The use of CF-sensing technology is not associated with increased success rate nor decreased complication rate in idiopathic outflow tract PVC ablation.

Efficacy and safety of ethanol infusion into the vein of Marshall for mitral isthmus ablation

INTRODUCTION

Chemical ablation by retrograde infusion of ethanol into the vein of Marshall (VOM-EI) can facilitate the achievement of mitral isthmus block. This study sought to describe the efficacy and safety of this technique.

METHODS AND RESULTS

Twenty-two consecutive patients (14 males, median age 71 years) with attempted VOM-EI for mitral isthmus ablation were included in the study. VOM-EI was successfully performed with a median of 4 ml of 96% ethanol in 19 patients (86%) and the mitral isthmus was successfully blocked in all (100%). Touch up endocardial and/or epicardial ablation after VOM-EI was necessary for 12 patients (63%). Perimitral flutter was present in 12 patients (63%) during VOM-EI and terminated or slowed by VOM-EI in 4 and 3 patients, respectively. The low-voltage area of the mitral isthmus region increased from 3.1 cm² (interquartile range [IQR] 0-7.9) before to 13.2 cm² (IQR: 8.2-15.0) after VOM-EI and correlated significantly with the volume of ethanol injected (p = .03). Median high-sensitive cardiac troponin-T increased significantly from 330 ng/L (IQR: 221-516) the evening of the procedure to 598 ng/L (IQR: 382-769; p = .02) the following morning. A small pericardial effusion occurred in three patients (16%), mild pericarditis in one (5%), and uneventful VOM dissection in two (11%). After a median follow-up of 3.5 months (IQR: 3.0-11.0), 10 of 18 patients (56%) with VOM-EI and available follow-up had arrhythmia recurrence. Repeat ablation was performed in five patients (50%) and peri-mitral flutter diagnosed in three (60%).

CONCLUSION

VOM-EI is feasible, safe, and effective to achieve acute mitral isthmus block.

Pre-procedural arrhythmia burden and the outcome of catheter ablation of idiopathic premature ventricular complexes

BACKGROUND

Radiofrequency catheter ablation of idiopathic premature ventricular complexes (PVCs) is an effective method for eliminating symptoms and preventing/reversing arrhythmia-induced cardiomyopathy. One reason for procedural failure is low PVC frequency during the procedure. We aimed to investigate the relation between pre-procedural PVC burden and outcome of idiopathic PVC catheter ablation.

METHODS

Patients who underwent idiopathic PVC ablation between 2013 and 2019 at two tertiary referral centers were retrospectively included. All procedures were performed using irrigated-tip ablation catheters and a 3D electro-anatomical mapping system. Sustained ablation success was defined as a ≥80% reduction of pre-procedural PVC burden determined by 24h-Holter at follow-up.

RESULTS

Overall, 254 patients (median age 54 years [IQR 42-64]; 47% male) were enrolled. The median pre-ablation PVC-burden was 22% (IQR 11-31%), which was reduced to a post-ablation PVC burden of 0.3% (IQR 0-4%) after a median of 90 days. Sustained ablation success was achieved in 182 patients (72%). Pre-procedural PVC burden did not differ between patients with sustained ablation success and recurrence during follow-up (median 21% vs. 22%, p = .76). When assessed in pre-ablation PVC-burden groups of ≤5%, 6-15%, 16-30%, and ≥31%, sustained ablation success was achieved in 67%, 75%, 71%, and 72%, respectively, with no significant difference (p = .89). Sustained ablation outcome for PVC-burden ≤5% versus >5% showed no difference either (67% vs. 72%, p = .52).

CONCLUSIONS

Pre-procedural Holter-determined PVC burden does not predict the outcome of idiopathic PVC ablation. Thus, catheter ablation may be a reasonable first choice also for patients with symptomatic yet rare PVCs.

The SilenT AtRial FIBrillation (STAR-FIB) study programme - design and rationale

AIMS OF THE STUDY

Anticoagulation of patients with screen-detected atrial fibrillation may prevent ischaemic strokes. The STAR-FIB study programme aims to determine the age- and sex-specific prevalence of silent atrial fibrillation and to develop a clinical prediction model to identify patients at risk of undiagnosed atrial fibrillation in a hospitalised patient population.

METHODS

The STAR-FIB study programme includes a prospective cohort study and a case-control study of hospitalised patients aged 65&ndash;84 years, evenly distributed for both age and sex. We recruited 795 patients without atrial fibrillation for the cohort study (49.2% females; median age 74.8 years). All patients had three serial 7-day Holter ECGs to screen for silent atrial fibrillation. The primary endpoint will be any episode of atrial fibrillation or atrial flutter of &ge;30 seconds duration. The age- and sex-specific prevalence of newly diagnosed atrial fibrillation will be estimated. For the case-control study, 120 patients with paroxysmal atrial fibrillation were recruited as cases (41.7% females; median age 74.6 years); controls will be randomly selected from the cohort study in a 2:1 ratio. All participants in the cohort study and all cases were prospectively evaluated including clinical, laboratory, echocardiographic and electrical parameters. A clinical prediction model for undiagnosed atrial fibrillation will be derived in the case-control study and externally validated in the cohort study.

CONCLUSIONS

The STAR-FIB study programme will estimate the age- and sex-specific prevalence of silent atrial fibrillation in a hospitalised patient population, and develop and validate a clinical prediction model to identify patients at risk of silent atrial fibrillation.

P311Hypertrophic cardiomyopathy and other forms of left ventricular hypertrophy. The P wave can make the difference

Background

Structural disarray of hypertrophied myocytes and interstitial fibrosis characterize hypertrophic cardiomyopathy (HCM). These morphological changes also affect atrial myocytes and, together with hemodynamic alterations because of HCM, may lead to atrial cardiomyopathy. 

Purpose

To investigate the incremental value of P-wave parameters to differentiate left ventricular hypertrophy (LVH) because of HCM from LVH in hypertensive heart disease (HHD) and athletes heart. 

Methods

In a prospective study, we compared electrocardiographic (including signal-averaged ECG of the P wave) and echocardiographic data of patients with HCM, HHD and athletes heart. We developed a predictive model with a simple scoring system to identify HCM.

Results

We compared data of 27 patients with HCM (70% males, 49.8 ± 14.5 years), 324 patients with HHD (52% males, 74.8 ± 5.5 years), and 215 subjects with athletes heart (72% males, 42.3 ± 7.5). The table shows the significant differences among the 3 groups. We included the following parameters into a predictive score to differentiate HCM from other forms of LVH: QRS width (&gt;88ms = 1 point), P-wave integral (&gt;688µVs = 1 point) and septum thickness (&gt;12mm = 2 points). A score &gt;2 (Youden index 0.626) correctly classified HCM in 81% of the cases with a sensitivity and specificity of 82% an 81%, respectively. 

Conclusion Differentiation of HCM from other forms of LVH is improved by including atrial parameters. A simple scoring system including septum thickness, QRS width and P wave integral allowed identification of patients with HCM with a sensitivity and specificity of &gt;80%. This score needs to be validated prospectively.

Table 1 HCM HHD Athletes P-value HCM vs HHD* HCM vs Athletes* 95%-CI P-value 95%-CI P-value P-wave duration [ms] 152.7 ± 25.8 143.9 ± 16.5 133.5 ± 14.2 &lt;0.001 -16.9 -24.6 to -9.1 &lt;0.001 -16.3 -22.7 to -9.9 &lt;0.001 P-wave integral [µVs] 850.4 ± 272.4 672.0 ± 235.4 773.1 ± 260.1 &lt;0.001 -198.6 -320.8 to -76.3 0.002 -68.2 -169.7 to 33.2 0.187 QRS [ms] 110.3 ± 27.3 96.9 ± 20.3 95.1 ± 9.8 &lt;0.001 -16.4 -24.7 to -8.1 &lt;0.001 -13.8 -20.8 to -6.9 &lt;0.001 QTc [ms] 447.9 ± 27.2 438.6 ± 24.5 414.0 ± 22.9 &lt;0.001 -21.1 -32.7 to -9.5 &lt;0.001 -30.8 -40.5 to -21.2 &lt;0.001 LVMMI [g/m2] 153.6 ± 55.5 133.5 ± 30.3 98.6 ± 19.7 &lt;0.001 -15.3 -29.7 to -0.9 0.038 -56.1 -67.7 to -44.6 &lt;0.001 IVS [ms] 16.8 ± 4.2 11.8 ± 2.2 10.3 ± 1.5 &lt;0.001 -5.2 -6.3 to -4.1 &lt;0.001 -6.4 -7.3 to -5.6 &lt;0.001 LAVI [ml/m2] 43.2 ± 13.9 30.5 ± 9.7 30.8 ± 9.5 &lt;0.001 -14.6 -20.0 to -9.3 &lt;0.001 -12.2 -16.6 to -7.9 &lt;0.001 The table shows the study result after univariate and multivariate (*; adjusting for age and sex) analysis.

Abstract Figure 1

P1492Comparison of the long-term performance of the quadripolar IS-4 and the bipolar IS-1 left ventricular lead for cardiac resynchronization therapy

BACKGROUND

The implantation of left ventricular (LV) leads for cardiac resynchronization therapy (CRT) and the management of lead-related complications can be challenging. The introduction of the quadripolar IS-4 LV lead may have facilitated the implantation procedure and may have reduced lead-related complications. Data of long-term follow-up (FU) comparing the IS-4 lead with the IS-1 LV lead are rare and conflicting.

PURPOSE

Comparison of lead-related complications and all-cause mortality between CRT patients who received an IS-4 or an IS-1 LV lead in the long-term FU.

METHODS

Adults with an indication for a CRT-Defibrillator or CRT-Pacemaker, a successful endovascular IS-4 or IS-1 LV lead implantation, and a minimal FU of three years were included in this retrospective study. The combined primary endpoint was freedom from lead-related complications defined as (i) occurrence of persisting high pacing threshold (&gt;2.75V/0.4ms), (ii) unresolved phrenic nerve stimulation, (iii) LV lead dislodgement/disruption, (iv) the necessity of re-interventions affecting the LV lead, and (v) LV lead deactivation/explantation. Secondary endpoints were all singular complications and all-cause mortality.

RESULTS

Eligible for the study were 133 patients (IS-4 n = 66; IS-1 n = 67) with a mean FU of 4.03 ± 1.93 years. Baseline characteristics of both patient groups did not differ significantly. Freedom from lead-related complications was higher in patients with an IS-4 lead as compared to an IS-1 lead (Figure 1; 87.9% vs. 65.7%; p = 0.002). The secondary outcomes showed a higher rate of LV lead dislodgement/disruption (4.5% vs. 17.9%; p = 0.015) in the IS-1 patient group and more patients suffered from unresolved phrenic nerve stimulation with an IS-1 lead (3.0% vs. 13.4%; p = 0.029). LV lead deactivation/explantation during FU and LV lead-related re-interventions were fewer in case of an IS-4 lead (4.5% vs 22.4%; p = 0.003; 6.1% vs. 17.9%; p = 0.036, respectively). The rate of persisting high pacing thresholds and all-cause mortality did not differ (4.5% vs. 9.0%; p = 0.492; 22.7% vs 25.4%; p = 0.721, respectively).

CONCLUSION

The quadripolar IS-4 LV lead showed in this retrospective study a better long-term performance than the bipolar IS-1 lead.

Abstract Figure 1

High incidence of diaphragmatic myopotential oversensing by a specific implantable cardioverter defibrillator

INTRODUCTION

Diaphragmatic myopotential oversensing (dMPO) by implantable cardioverter defibrillators (ICDs) is thought to be a rare condition that can be misdiagnosed as lead failure and lead to unnecessary lead replacement. We observed several cases of dMPO in patients with Sorin/LivaNova ICDs (MicroPort Sci.). We sought to systematically assess the incidence of dMPO in patients with Sorin/LivaNova ICDs.

METHODS AND RESULTS

A predefined number of 100 consecutive patients with Sorin/LivaNova ICDs were prospectively included in the device clinic of our center. Stored arrhythmia episodes were checked for spontaneous dMPO. In addition, we performed provocation maneuvers by Valsalva. At least one episode of spontaneous or provoked dMPO was seen in 12 (12%) of the 100 patients included in the study (86% males, median age: 66 years). Nine of 89 patients (10%) with true bipolar and 3 of 11 patients (27%) with integrated bipolar sensing configuration were affected. Spontaneous dMPO was observed in 7 of 58 patients (12%) with sensitivity programmed to 0.4 mV and in 2 of 42 patients (5%) with sensitivity programmed to 0.6 mV (not significant). In three patients, dMPO could be provoked with no spontaneous episodes recorded. In two nonpacemaker-dependent patients with a CRT-D, ventricular pacing was temporarily inhibited. No antitachycardia therapy was triggered by dMPO in any patient.

CONCLUSIONS

DMPO is frequent in patients with Sorin/LivaNova ICDs, especially with sensitivity programmed to 0.4 mV. It also frequently occurs with true bipolar sensing configuration. DMPO should not be misinterpreted as lead failure to avoid unnecessary lead replacement.

P1007Efficacy and safety of atrial ablation procedures in patients with complete d-TGA and atrial switch at a Swiss tertiary center

Introduction

Patients with complete transposition of the great arteries (d-TGA) and atrial switch face a high lifetime risk of arrhythmias. Interventions in these patients are challenging because of their particular anatomy. Reports on ablation procedures in this patient population are scarce and missing for Switzerland.

Method

We retrospectively analyzed all ablation procedures performed in the above-mentioned population at a Swiss tertiary care center.

Results

Among 73 d-TGA pts. (71% male; N=37 Senning; N=36 Mustard) followed at our center, 17 ablations were performed in 11 pts. (15%; one ablation in 8 pts., two in 2 pts. and five in 1 patient). Median age at first ablation was 34 years (range 15–49 years). A total of 17 different intra-atrial reentry tachycardias (IART) and 3 AVNRT were targeted. Of the IART, 10 were cavotricuspid isthmus (CTI)-dependent and 7 were not. In two procedures (12%) only the systemic venous (SV) baffle was accessed for ablation. In 15 procedures (88%), ablation was performed within the pulmonary venous (PV) baffle. Access to the PV baffle was retrograde via the aorta in 6 cases (35%), via a baffle leak in 3 (18%) and via baffle puncture in 6 (35%). All procedures with retrograde approach to the PV baffle or with SV baffle only ablation were performed up to January 2012 and all remaining procedures afterwards. The 3 pts. requiring repeat procedures had retrograde or SV baffle approaches initially, and one additional ablation via baffle puncture was successful. The CTI was targeted in 10 pts. (91%) and ablation was finally successful in all with bidirectional block demonstrated in 8 pts. The coronary sinus was found to drain into the SV baffle in 5 pts. (46%) and useful for assessment of CTI block. The seven CTI-independent IART were scar-related micro-reentries. Ablation of all 3 AVNRTs was successful after one procedure without recurrence. Slow pathway ablation was performed in the SV baffle in two and in the PV baffle in one case (Figure). After a median follow-up of 7 months (range 2–186 months) 9 pts. are without recurrence and in 2 pts. rare self-limited arrhythmias still occur. No procedural complications occurred.

Conclusion

Arrhythmias in patients with complete d-TGA and atrial switch are mainly CTI-dependent IART or scar-related micro-reentries, and a few patients also have AVNRT. Ablation of these arrhythmias is safe and successful if PV baffle access is achieved via a baffle leak or baffle puncture.

Usefulness of Genetic Testing in Sudden Cardiac Arrest Survivors With or Without Previous Clinical Evidence of Heart Disease

Genetic testing in survivors of sudden cardiac arrest (SCA) with a suspicious cardiac phenotype is considered clinically useful, whereas its value in the absence of phenotype is disputed. We aimed to evaluate the clinical utility of genetic testing in survivors of SCA with or without cardiac phenotype. Sixty unrelated SCA survivors (median age: 34 [interquartile range 20 to 43] years, 82% male) without coronary artery disease were included: 24 (40%) with detectable cardiac phenotype (Ph(+)SCA) after the SCA event and 36 (60%) with no clear cardiac phenotype (Ph(-)SCA). The targeted exome sequencing was performed using the TruSight-One Sequencing Panel (Illumina). Variants in 185 clinically relevant cardiac genes with minor allele frequency <1% were analyzed. A total of 32 pathogenic or likely pathogenic variants were found in 27 (45%) patients: 17 (71%) in the Ph(+)SCA group and 10 (28%) in the Ph(-)SCA group. Sixteen (67%) Ph(+)SCA patients hosted mutations congruent with the suspected phenotype, in which 12 (50%) were cardiomyopathies and 4 (17%) channelopathies. In Ph(-)SCA cases, 6 (17%) carried a mutation in cardiac ion channel genes that could explain the event. The additional 4 (11%) mutations in this group, could not explain the phenotype and require additional studies. In conclusion, cardiac genetic testing was positive in nearly 2/3 patients of the Ph(+)SCA group and in 1/6 of the Ph(-)SCA group. The test was useful in both groups to identify or confirm an inherited heart disease, with an important impact on the patient care and first-degree relatives at risk.

Substrate mapping for scar-related ventricular tachycardia in patients with resynchronization therapy-the importance of the pacing mode

PURPOSE

Targets for substrate-based catheter ablation of scar-related ventricular tachycardia (VT) include sites with fractionated and late potentials (LPs). We hypothesized that in patients with cardiac resynchronization therapy (CRT), the pacing mode may influence the timing of abnormal electrograms (EGMs) relative to the surface QRS complex.

METHODS

We assessed bipolar EGM characteristics in left ventricular low bipolar voltage areas (< 1.5 mV) from 10 patients with coronary disease and a CRT device undergoing catheter ablation for VT. EGMs at 81 sites were analyzed during three different pacing modes (biventricular (BiV), right ventricular (RV)-only, and left ventricular (LV)-only) pacing.

RESULTS

Stimulus to end of local electrogram duration (Stim-to-eEGM) depended significantly on the stimulation site (BiV, LV, or RV, p = 0.032). Single-chamber pacing unmasked LPs, not present during BiV pacing, in three patients. In another three patients, a concomitant increase in stimulus to end of surface QRS duration caused by single-site pacing compensated for the increase in Stim-to-eEGM duration, thereby prohibiting LP unmasking.

CONCLUSION

The sequence of ventricular activation, as determined by the pacing site in patients with CRT devices, has a major influence on the detection of late potentials during substrate-guided ablation. Further study is warranted to define the optimal approaches, including the rhythm, for substrate mapping, but our findings suggest that BiV pacing may be most likely to obscure detection of late potentials as compared to single-site pacing.

Downstream overdrive pacing and intracardiac concealed fusion to guide rapid identification of atrial tachycardia after atrial fibrillation ablation

Aims

Atrial tachycardia (AT) related to atrial fibrillation (AF) ablation frequently poses a diagnostic challenge. Downstream overdrive pacing (DOP) can be used to rapidly detect reentry and assess proximity of a pacing site to an AT circuit or focus. We hypothesized that systematic DOP using multielectrode catheters would facilitate AT mapping.

Methods and results

DOP identified constant fusion when the post-pacing interval (PPI)-tachycardia cycle length (TCL) <40 ms and stimulus to adjacent upstream atrial electrogram interval >75% of TCL. Mapping was performed as follows: (i) CS DOP, (ii) DOP at left atrial (LA) roof, (iii) DOP at selected LA sites based on prior DOP attempts, and (iv) mapping and ablation at regions of fractionated electrograms in region of AT. Activation mapping was performed at operator discretion. AT diagnosis was confirmed by successful ablation or additional mapping when ablation was unsuccessful. Fifty consecutive patients with sustained AT underwent mapping of 68 ATs, of whom 42 (62%) were macroreentrant, 19 were locally reentrant (28%), and 7 (10%) were focal. AT was correctly identified with a median of three DOP attempts. All macroreentrant ATs were identified with ≤6 DOP attempts. One AT (1.6%) was terminated by DOP, and three ATs (4.8%) required activation mapping. Intracardiac concealed fusion was seen in 26 ATs (38%), each of which was successfully ablated.

Conclusion

Reentry could be demonstrated in a substantial majority of AF ablation-related AT. A stepwise diagnostic approach using DOP and recognition of intracardiac concealed fusion can be used to rapidly identify and ablate reentrant AT.

Impact of Number of Oral Antiarrhythmic Drug Failures Before Referral on Outcomes Following Catheter Ablation of Ventricular Tachycardia

OBJECTIVES

This study sought to examine the relationship between the number of oral antiarrhythmic drug (AAD) failures before referral for ventricular tachycardia (VT) ablation and subsequent clinical outcomes.

BACKGROUND

Failure of AADs prompts referral for VT ablation.

METHODS

Consecutive patients (n = 669) with sustained VT who were referred for a first-time ablation were divided into 2 groups according to the number of oral Class 1 or 3 AAD failures before referral: single-drug failure (≤1 AAD; n = 256) or multidrug failure (>1 AADs; n = 413). Outcomes were stratified according to underlying disease type (no structural heart disease [SHD] [n = 87]; ischemic cardiomyopathy [ICM] [n = 368]; and ischemic cardiomyopathy [NICM] [n = 214]) and reported at a mean follow-up of 35 ± 46 months.

RESULTS

Patients with multidrug failure, compared with patients with single-drug failure, had more advanced SHD and required more extensive ablation to control arrhythmia. Multidrug failure, compared with single-drug failure, was associated with lower ventricular arrhythmia-free survival in ICM (46 ± 4% vs. 58 ± 6%; p = 0.03) and NICM (26 ± 5% vs. 49 ± 6%; p = 0.008), but not in the absence of SHD (71 ± 8% vs. 85 ± 7%; p = 0.10). Overall survival was lower in multidrug failure versus single-drug failure groups in patients with ICM (71 ± 3% vs. 84 ± 4%; p = 0.03) and NICM (70 ± 5% vs. 88 ± 4%; p < 0.001). Multidrug failure was independently associated with a higher risk of ventricular arrhythmia recurrence (hazard ratio: 1.6; p = 0.01) and mortality in NICM (hazard ratio: 2.6; p = 0.008), but not in ICM.

CONCLUSIONS

Patients with SHD and failure of multiple oral AADs before VT ablation referral have more advanced heart disease and worse clinical outcomes following ablation, especially in NICM.

Significance of Inducible Nonsustained Ventricular Tachycardias After Catheter Ablation for Ventricular Tachycardia in Ischemic Cardiomyopathy

BACKGROUND

Noninducibility of sustained monomorphic ventricular tachycardia (SMVT) postablation does not insure absence of later recurrence in patients with ischemic cardiomyopathy. This study aims to determine the relation between inducible nonsustained VT postablation and VT recurrences.

METHODS AND RESULTS

One hundred sixty-five consecutive patients (156 male; age 68±9 years) underwent ablation for SMVT because of ischemic cardiomyopathy; 44 patients who did not have induction testing or in whom only ventricular fibrillation was induced after ablation were excluded. In 38 patients (23%), SMVT was inducible (group C). Of the 83 patients without inducible SMVT after ablation, nonsustained VT defined as ≥5 beats lasting for <30 s, was induced in 34 patients (group B, 21%), whereas the remaining 49 patients had no VT induced by the induction test (group A, 30%). Over a median follow-up of 18.7 months, freedom from recurrent VT at 24 months was 60% in group A, 45% in group B (P=0.017 versus group A), and 38% in group C (P=0.005 versus group A). In patients without inducible SMVT, inducible nonsustained VT and left ventricular ejection fraction was independently associated with VT recurrence (hazard ratio, 3.66 and 1.07; 95% CI, 1.3-11.1 and 1.01-1.14).

CONCLUSIONS

Inducible nonsustained VT postablation suggests the continued presence of functional arrhythmia substrate. Further trials are needed to assess whether additional ablation would improve outcome in this group.

Substrate-Based Ablation Versus Ablation Guided by Activation and Entrainment Mapping for Ventricular Tachycardia: A Systematic Review and Meta-Analysis

INTRODUCTION

Substrate-based ablation for scar-related ventricular tachycardia (VT) has gained prominence: however, there is limited data comparing it to ablation guided predominantly by activation and entrainment mapping of inducible and hemodynamically tolerated VTs. We compared the acute procedural efficacy and outcomes of predominantly substrate-based ablation versus ablation guided predominantly by activation and entrainment mapping.

METHODS AND RESULTS

Database searches through April 2016 identified 6 eligible studies (enrolling 403 patients, with 1 randomized study) comparing the 2 strategies. The relative risk of VT recurrence at follow-up was assessed as the primary outcome using a random-effects meta-analysis. Secondary endpoints of acute success (based on noninducibility of VT), procedural complications, and mortality were assessed using weighted mean difference with the random effects model. At a median follow-up of 18 months, the relative risk (RR) of VT recurrence was not significantly different with substrate-based versus activation/entrainment guided VT ablation (0.72, 95% confidence interval [CI] 0.44-1.18), P = 0.2). Acute success (RR 1.02, 95% CI 0.95-1.1, P = 0.6), procedural complications (RR 0.8, 95% CI 0.35-1.82, P = 0.5) cardiovascular mortality and total mortality did not differ significantly (RR 0.83, 95% CI 0.38-1.79, P = 0.6 and RR 0.76, 95% CI 0.36-1.59, P = 0.5, respectively).

CONCLUSIONS

This meta-analysis demonstrates similar acute procedural efficacy, and complications, VT recurrence and mortality rates when comparing a predominantly substrate-based ablation strategy to a strategy guided predominantly by activation and entrainment mapping of inducible and hemodynamically tolerated VTs.

Multicenter Experience With Catheter Ablation for Ventricular Tachycardia in Lamin A/C Cardiomyopathy

Background—

Lamin A/C ( LMNA ) cardiomyopathy is a genetic disease with a proclivity for ventricular arrhythmias. We describe the multicenter experience with percutaneous catheter ablation of sustained monomorphic ventricular tachycardia (VT) in LMNA cardiomyopathy.

Methods and Results—

Twenty-five consecutive LMNA mutation patients from 4 centers were included (mean age, 55±9 years; ejection fraction, 34±12%; VT storm in 36%). Complete atrioventricular block was present in 11 patients; 3 patients were on mechanical circulatory support for severe heart failure. A median of 3 VTs were inducible per patient; in 82%, mapping was consistent with origin from scar in the basal left ventricle, particularly the septum, but also basal inferior wall and subaortic mitral continuity. After multiple procedures (median 2/patient; transcoronary alcohol in 6 and surgical cryoablation in 2 patients), acute success (noninducibility of any VT) was achieved in only 25% of patients. Partial success (inducibility of a nonclinical VT only: 50%) and failure (persistent inducibility of clinical VT: 12.5%) was attributed to intramural septal substrate in 13 of 18 patients (72%). Complications occurred in 25% of patients. After a median follow-up of 7 months after the last procedure, 91% experienced ≥1 VT recurrence, 44% received or were awaiting mechanical circulatory support or transplant for end-stage heart failure, and 26% died.

Conclusions—

Catheter ablation of VT associated with LMNA cardiomyopathy is associated with poor outcomes including high rate of arrhythmia recurrence, progression to end-stage heart failure, and high mortality. Basal septal scar and intramural VT origin makes VT ablation challenging in this population.

Long-term outcomes after catheter ablation of ventricular tachycardia in patients with and without structural heart disease

BACKGROUND

Long-term outcomes after ventricular tachycardia (VT) ablation are sparsely described.

OBJECTIVES

The purpose of this study was to describe long-term prognosis after VT ablation in patients with no structural heart disease (no SHD), ischemic cardiomyopathy (ICM), and nonischemic cardiomyopathy (NICM).

METHODS

Consecutive patients (N = 695: no SHD, 98; ICM, 358; NICM, 239) ablated for sustained VT were followed for a median of 6 years. Acute procedural parameters (complete success [noninducibility of any VT]) and outcomes after multiple procedures were reported.

RESULTS

Compared with patients with no SHD or NICM, patients with ICM were the oldest, were more likely to be men, lowest left ventricular ejection fraction, highest drug failures, VT storms, and number of inducible VTs. Complete procedure success was highest in patients with no SHD than in patients with ICM and those with NICM (79%, 56%, 60%, respectively; P < .001). At 6 years, ventricular arrhythmia (VA)-free survival was highest in patients with no SHD (77%) than in patients with ICM (54%) and those with NICM (38%) (P < .001), and overall survival was lowest in patients with ICM (48%), followed by patients with NICM (74%) and patients with no SHD (100%) (P < .001). Age, left ventricular ejection fraction, presence of SHD, acute procedural success (noninducibility of any VT), major complications, need for nonradiofrequency ablation modalities, and VA recurrence were independently associated with all-cause mortality.

CONCLUSION

Long-term follow-up after VT ablation shows excellent prognosis in the absence of SHD, highest VA recurrence, and transplantation in patients with NICM and highest mortality in patients with ICM. The extremely low mortality for those without SHD suggests that VT in this population is rarely an initial presentation of a myopathic process.