Chronic electrical performance of a new ultra-thin left ventricular quadripolar pacing lead

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): H2020-FTI [Fast Track to Innovation] Pilot-2016 and MicroPort CRM

Background

Left ventricular (LV) lead positioning is an important contributor to cardiac resynchronization therapy (CRT) response. Multiple additional LV sites could be stimulated by passing a new ultra-thin (1.2 Fr, 0.4 mm) quadripolar microlead from one LV vein into another via venous collaterals.

Purpose

Study the acute and chronic stability and electrical pacing performance of a novel 1.2 Fr quadripolar microlead ("Axone 4LV").

Methods

Seven healthy adult dogs underwent CRT defibrillator implantation, including a right ventricular lead and the microlead. The microlead was advanced into the coronary sinus network using a dedicated microguide catheter. The animals were followed up at 1, 15, 30 and 90 days post-implant to evaluate chronic stability and electrical pacing performance.

Results

Successful uncomplicated implantation was achieved in all cases. Despite the small diameter of the distal veins and collaterals, placement of the pacing electrodes in two different LV veins was feasible via available collateral passages. Lead position was stable in all cases and over the entire study period. Capture threshold and pacing impedance at 90 days post-implant were 1.7 ± 0.5 V with 1323 ± 245 Ω, respectively, at 0.5 ms pulse width. The mean pacing energy to get capture was 1.1 ± 0.5 µJ and less than 2 µJ in all cases (2 µJ ≈ 1.4 V @500 Ω, 0.5 ms). No phrenic nerve stimulation was observed during pacing.

Conclusions

The novel 1.2 Fr quadripolar microlead demonstrated adequate stability and good electrical performance allied to low energy consumption. This quadripolar microlead may extend pacing options while increasing device longevity in CRT. Changes in pacing parameters over time Post-implant Follow-up Pacing Threshold Pacing Impedance Pacing Energy 1 day 1.4 ± 0.7 V 1294 ± 270 Ω 0.8 ± 0.7 µJ 15 days 1.9 ± 0.9 V 1336 ± 274 Ω 1.8 ± 1.8 µJ 30 days 1.8 ± 0.7 V 1187 ± 303 Ω 1.5 ± 1.2 µJ 90 days 1.7 ± 0.5 V 1323 ± 245 Ω 1.1 ± 0.5 µJ

Impact of initial rhythm control with cryoballoon ablation versus drug therapy on atrial fibrillation recurrence and quality of life: results from the Cryo-FIRST study

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Medtronic

OnBehalf

The Cryo-FIRST Investigators

Background

Cryoballoon ablation (CBA) as a first-line rhythm control strategy is superior to antiarrhythmic drugs (AADs) for preventing atrial arrhythmia recurrence; however, the impact of first-line CBA specifically on atrial fibrillation (AF) recurrence and quality of life (QoL) has not been well characterized.

Purpose

To compare AF recurrence and QoL following first-line CBA vs. AAD therapy in patients with paroxysmal AF within the CryoFIRST trial (NCT01803438).

Methods

Patients with recurrent symptomatic paroxysmal AF who had not been administered class I or III AAD therapy for >48 hours were enrolled at 18 sites in 9 countries. Patients were randomized (1:1) to CBA or AAD treatment (Class I or III). Subjects were followed by 7-day Holter at 1, 3, 6, 9, and 12 months. Time-to-first AF recurrence outside of a 90-day blanking period was estimated by Kaplan-Meier analysis.  QoL was evaluated using the Atrial Fibrillation Effect on Quality of Life (AFEQT) and 36-Item Short Form Health Survey (SF-36) v2 questionnaires.

Results

Of the 218 randomized subjects, 187 (86%) completed the 12-month follow-up. By intention-to-treat (ITT) analysis, freedom from AF after blanking was achieved in 86.6% in the CBA and 74.5% in the AAD group (p = 0.023).  There was no difference in the time-to-first serious adverse event between groups. In total, 84.3% of patients in the CBA vs. 75.0% of patients in the AAD arm had a clinically important improvement (≥5 points) in the AFEQT summary score.  The adjusted mean difference in the AFEQT summary score at 12 months was 9.9 points higher in the CBA group (95% CI: 5.5-14.2; P < 0.001).  All AFEQT subscale scores were more favorable in the CBA vs. AAD group at 12 months.  There were no significant group differences in any of the SF-36 health domain scores at 12 months in the ITT analysis.  In the per-protocol analysis, clinically important and significant group differences in favor of CBA were observed at 12 months for 3 of 8 SF-36 health domain scores (physical functioning, general health and social functioning).

Conclusion

CBA is superior to AAD for preventing AF recurrence and improving AF-specific QoL in patients with paroxysmal AF. AFEQT Scores at Baseline and 12 MonthsAFEQT Score, Mean ± Standard DeviationCBAAADAdjusted Mean Difference at 12 Months (CBA vs. AAD)p-valueBaseline12 MonthsBaseline12 MonthsDaily Activities65.3 ± 25.887.8 ± 17.161.0 ± 27.976.6 ± 25.48.9 (3.2-14.6)0.002Symptoms59.9 ± 24.888.8 ± 15.658.4 ± 25.280.9 ± 22.27.1 (1.5-12.7)0.014Treatment Concern59.9 ± 23.189.8 ± 14.060.4 ± 24.577.7 ± 22.212.7 (7.9-17.5)<0.001AFEQT, Atrial Fibrillation Effect on Quality of Life questionnaire. CBA, cryoballoon ablation. AAD antiarrhythmic drug.Abstract Figure. Freedom From Atrial Fibrillation

Quality of life measured in first-line therapy during the Cryo-FIRST study: a comparison between cryoballoon catheter ablation versus antiarrhythmic drug therapy

Background

By consensus statements, catheter ablation is a recommended treatment for patients with symptomatic drug-refractory paroxysmal atrial fibrillation (AF), as patients try to alleviate the burdensome AF symptoms that reduce the Quality of Life (QoL). Yet, first-line treatment of symptomatic patients via catheter ablation prior to initiation of antiarrhythmic drugs (AADs) is only a reasonable alternative (Class IIa). Clearly, more clinical data is necessary that compares catheter ablation to AAD therapy in treatment naïve patients.

Purpose

The Cryo-FIRST trial was designed to compare AAD treatment against pulmonary vein isolation (PVI) while using a cryoballoon catheter (Arctic Front Advance; Medtronic, Inc.). This current data analysis examines the QoL endpoints when comparing AADs to cryoballoon ablation in patients with symptomatic treatment naïve paroxysmal AF.

Methods

This randomized multicenter trial enrolled 220 patients from 18 sites in 9 countries (Europe, Australia, and Latin America) in a prospective open-blinded endpoint study design. Patients had not been administered a class I or III AAD for longer than 48 hours for inclusion into the study. Subjects were randomized (1:1) into a cohort that was administered AAD therapy or a cohort that received PVI via cryoablation. The prespecified QoL endpoint at 12 months was measured using the Atrial Fibrillation Effect on Quality of Life (AFEQT) scores, and QoL recordings were taken at baseline, 1, 3, 6, 9, and 12 months following the index treatment.

Results

Of the 218 patients randomized (age 52±13 years, 68% male) 86% completed the 12-month follow-up. Crossovers occurred in 9% of subjects (N=20), including: 1 subject in the cryoablation arm and 19 subjects in the AAD arm. At 12 months, 86.5% of the patients in the cryoablation arm and 70.4% of the patients in the AAD arm where without symptoms (EHRA score 1). The mean AFEQT summary score was more favorable in the catheter ablation group compared to the drug therapy group at 12 months (88.9 vs. 78.1 points, respectively). The adjusted difference was 9.9 points (95% CI: 5.5–14.2; P<0.0001).

Conclusions

Cryoballoon ablation resulted in a significant improvement in QoL at 12 months compared to AAD therapy in treatment naïve patients with first-line symptomatic paroxysmal AF.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Medtronic International Trading Sàrl

Can atrioventricular node ablation be safely performed in patients with permanent His bundle pacing? Data from a multicentric registry

Introduction

Ventricular rate control is essential in the management of atrial fibrillation. Atrioventricular node ablation (AVNA) and ventricular pacing can be an effective option when pharmacological rate control is insufficient. However, right ventricular pacing (RVP) induces ventricular desynchronization in patients with normal QRS and increases the risk of heart failure on long term. His bundle pacing (HBP) is a physiological alternative to RVP. Observational studies have demonstrated the feasibility of HBP but there is still very limited data about the feasibility of AVNA after HBP.

Purpose

To evaluate feasibility and safety of HBP followed by AVNA in patients with non-controlled atrial arrhythmia.

Methods

We included in three hospitals between september 2017 and december 2019 all patients who underwent AVNA for non-controlled atrial arrhythmia after permanent His bundle pacing. No back-up right ventricular lead was implanted. AVNA procedures were performed with 8 mm-tip ablation catheter. Acute HBP threshold increase during AVNA was defined as a threshold elevation >1V. His bundle capture (HBC) thresholds were recorded at 3 months follow-up.

Results

AVNA after HBP lead implantation was performed in 45 patients. HBP and AVNA were performed simultaneously during the same procedure in 10. AVNA was successful in 32 of 45 patients (71%). Modulation of the AV node conduction was obtained in 7 patients (16%). The mean procedure duration was 42±24min, and mean fluoroscopy duration was 6.4±8min. A mean number of 7.7±9.9 RF applications (347±483 sec) were delivered to obtain complete / incomplete AV block. Acute HBC threshold increase occurred in 8 patients (18%) with return to baseline value at day 1 in 5 patients. There was no lead dislodgment during the AVNA procedures. Mean HBC threshold at implant was 1.26±0.69V@0.5ms and slightly increased at 3 months follow-up (1.34±0.86V@0.5ms). AV node re-conduction was observed in 5 patients (16% of the successful procedures) with a second successful ablation procedure in 4 patients. No ventricular lead revision was required during the follow-up period. The baseline native QRS duration was 102±21 ms and the paced QRS duration was 107±18 ms.

Conclusion

AVNA combined with HBP for non-controlled atrial arrhythmia is feasible and does not compromise HBC but seems technically difficult with significant AV nodal re-conduction rate. The presence of a back-up right ventricular lead could have changed our results and therefore would require further evaluation.

Unipolar HBP after AV node ablation

Funding Acknowledgement

Type of funding source: None

Joint Position Paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology (SFC) and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) on magnetic resonance imaging in patients with cardiac electronic implantable devices

Magnetic resonance imaging (MRI) has become the reference imaging for the management of a large number of diseases. The number of MR examinations increases every year, simultaneously with the number of patients receiving a cardiac electronic implantable device (CEID). A CEID was considered an absolute contraindication for MRI for years. The progressive replacement of conventional pacemakers and defibrillators by MR-conditional CEIDs and recent data on the safety of MRI in patients with "MR-nonconditional" CEIDs have progressively increased the demand for MRI in patients with a CEID. However, some risks are associated with MRI in CEID carriers, even with "MR-conditional" devices because these devices are not "MR-safe". A specific programing of the device in "MR-mode" and monitoring patients during MRI remain mandatory for all patients with a CEID. A standardized patient workflow based on an institutional protocol should be established in each institution performing such examinations. This joint position paper of the Working Group of Pacing and Electrophysiology of the French Society of Cardiology and the Société française d'imagerie cardiaque et vasculaire diagnostique et interventionnelle (SFICV) describes the effect and risks associated with MRI in CEID carriers. We propose recommendations for patient workflow and monitoring and CEID programming in MR-conditional, "MR-conditional nonguaranteed" and MR-nonconditional devices.

2396Long-term follow-up of patients with tetralogy of Fallot and implantable cardioverter defibrillator

Background

Ventricular arrhythmias and sudden death are potential late complications in patients with tetralogy of Fallot. Data regarding the value of implantable cardioverter defibrillators (ICD) are scarce in this population.

Purpose

To assess long-term rates of appropriate ICD therapies and ICD-related complications in a large registry of ICD recipients with tetralogy of Fallot.

Methods

The DAI-T4F study is an ongoing national French registry including all patients with tetralogy of Fallot and ICD (NCT03837574). Information have been collected prospectively since 2010 with annual update. Baseline patient characteristics and clinical events during follow-up were analyzed with central adjudication. Cox proportional hazard models were used to identify factors associated with appropriate ICD therapies and complications.

Results

A total of 134 patients (median age 41.7 years, 70.7% males) were enrolled. The median (IQR) follow-up duration was 6.1 (2.7–10.2) years. ICDs were implanted for primary prevention in 47 (35.1%) patients and for secondary prevention in 87 (64.9%) patients. Overall, 14 (29.8%) and 45 (51.7%) patients received at least one appropriate ICD therapy in primary and secondary prevention, respectively, giving annual incidences of 5.5% and 7.1% (p=0.06). Patients with altered left ventricle ejection fraction (LVEF) at inclusion ≤35% experienced less appropriate ICD therapies (HR=0.31, 95% CI: 0.11–0.86, p=0.02), whereas a history of sustained or non-sustained ventricular arrhythmia (HR=2.7, 95% CI: 1.2–3.9, p=0.03) was positively associated with appropriate therapies. Fifty-seven (42.5%) patients had ICD-related complications, including 32 (24.2%) inappropriate ICD shocks, 22 (16.4%) significant lead dysfunction, 14 (10.4%) device infection, and 5 (3.7%) generator dysfunction/recall. History of supraventricular arrhythmias (HR=2.2, 95% CI: 1.2–3.7, p=0.01) and congestive heart failure (HR=2.0, 95% CI: 1.2–3.6, p=0.01) were both associated with a higher risk of complications. During follow-up, 7 (5.2%) patients underwent cardiac transplantation and 12 (9.0%) patients died, mainly from progressive heart failure (n=5). Only one sudden death due to electrical storm was recorded.

Figure 1

Conclusions

Appropriate therapies are frequent in patients with tetralogy of Fallot and ICDs, including in primary prevention. The relatively important proportion of ICD-related complication highlights the need for improving risk stratification in this population, considering associated conditions in the individual benefit-risk equation.

P1240Is resynchronization therapy really efficient in laminopathy?

Introduction

Laminopathy (LMNA) is a group of rare disease caused by a mutation of lamin A/C genes. Heart transplantation (HT) is often required. Cardiac resynchronization therapy (CRT) may be an option to postpone HT.

Purpose

To describe characteristics and outcome of LMNA patients receiving CRT.

Methods

All consecutive LMNA patients implanted with a CRT device for conventional indications were included in the study. Clinical and echocardiographic (TTE) data were collected during the follow-up period.

Results

From 2002 to 2017, 68 LMNA patients had CRT implantation. Despite CRT, 30/68 patients (44%) had HT. Population divided into two groups according to response to CRT. Patients were considered without benefit (WHOB-CRT group) if they experienced severe events (inscription on heart transplantation list or death) within two years after CRT implantation. Other patients were in the WB-CRT group. TTE and clinical parameters are described in Table 1.

Table 1 Parameters WB-CRT (n=33) WHOB-CRT (n=35) P-value At implantation   Age (years) 52.3±9.7 50.6±9.5 0.27   Women 9 (27%) 13 (37%) 0.45   NYHA class 2.7±0.6 2.8±0.7 0.45   LVEF (%) 33.2±8.8 31.3±7 0.64   LVEDD (mm) 60±6.9 60±6.9 0.96   TAPSE (mm) 23±3.7 14±4.8 0.002 At last follow up   NYHA class 2.2±0.6 2.9±0.7 <0.001   LVEF (%) 36.4±11 27±9 <0.001   LVEDD (mm) 59±5.5 59±7.7 0.98   TAPSE (mm) 19.9±5.5 12.3±3.3 0.003 Left ventricular ejection fraction (LVEF); Left ventricular end diastolic diameter (LVEDD); Tricuspid annular plane systolic excursion (TAPSE).

Conclusion

Cardiac resynchronization therapy is less efficient in LMNA patients. An impaired right ventricular stroke function seems to be the only predictive factor leading to poor response to CRT.

P6018Can chronic his bundle pacing be safely started in centers with lack of experience of this technique? Data from a multicentric registry

Introduction

Right ventricular pacing (RVP) induces ventricular asynchrony in patients with normal QRS and increases the risk of heart failure and atrial fibrillation on long term. His bundle pacing (HBP) is a physiological alternative to RVP. Interest in HBP has been hampered in part by technical challenges and limited implantation tool set. Recent studies assessed feasibility and safety in expert centers with a vast experience of HBP. These results may not apply to less experienced centers.

Purpose

To evaluate feasibility and safety of permanent his bundle pacing in hospitals with limited technical training to this technique and to evaluate stability of his bundle capture thresholds at 3 months follow up.

Methods

We included all patients who underwent pacemaker implantation with attempt of HBP in three hospitals between September 2017 and December 2018. All the 5 operators were novice for HBP at the beginning of the study. Selective his bundle capture (HBC) was defined as concordance of QRS and T waves complexes with the native ECG (patients with underlying bundle branch block may normalize), presence of a delay between spike and QRS complex, absence of widening of the QRS at a low pacing output, and recordable his bundle electrogram. At 3 months follow-up, his bundle capture thresholds, R-wave amplitudes and pacing impedances were recorded.

Results

HPB was successful in 51 of 58 patients (87.9%); selective HBC was obtained in 40 patients while nonselective HBC occurred in 11 patients. Indication for pacemaker implantation was atrioventricular conduction disease in 31 patients (53%), sinus node dysfunction in 5 patients (9%) and AV nodal ablation for non-controlled atrial arrhythmias in 22 patients (38%). AV nodal ablation was performed during the same procedure in 14 patients. The mean procedure duration was 75±8 min, and mean fluoroscopy duration was 10±2 min. The mean HBP threshold was 1.47±0.27 V and did not increase after a 3 months follow-up (1.12±0.18 V). Only 7 patients (14%) had HBP threshold >2V/0.5ms. The mean impedance was 477±37 Ω and slightly decreased at 3 months (364±24Ω). The mean R-wave amplitude was 4.1±1 mV at implantation and 3.2±0.6 mV at 3 months. Bundle branch block correction was achieved in 5 of 7 patients with underlying left bundle branch block. There was no pericardial effusion, no pneumothorax and no device infection. Ventricular lead revision was required at 3 months in one patient for sudden threshold increase, without obvious dislodgement.

LBBB correction after HBP

Conclusion

His bundle pacing performed by novice operators to this technique appeared feasible and safe. The mean HBP threshold did not increase at 3 months follow-up.

5164New risk prediction score for life-threatening ventricular tachyarrhythmias in laminopathies

Background

An accurate estimation of the risk of life-threatening (LT) ventricular tachyarrhythmia (VTA) in patients with LMNA mutations is crucial to select candidates for implantable cardioverter defibrillator (ICD) implantation.

Methods

We included 839 adult patients with LMNA mutations, including 660 from a French nationwide registry in the development sample, and 179 from other countries, referred to 5 tertiary centers for cardiomyopathies, in the validation sample. LTVTA was defined as a) sudden cardiac death or b) ICD-treated or hemodynamically unstable VTA. The prognostic model was derived using Fine-Gray's regression model. The net reclassification was compared with current clinical practice guidelines. The results are presented as means (standard deviation) or medians [interquartile range].

Results

We included 444 patients 40.6 (14.1) years of age in the derivation sample and 145 patients 38.2 (15.0) years in the validation sample, of whom 86 (19.3%) and 34 (23.4%) suffered LTVTA over 3.6 [1.0–7.2] and 5.1 [2.0–9.3] years of follow-up, respectively. Predictors of LTVTA in the derivation sample were: male sex, non-missense LMNA mutation, 1st degree and higher atrioventricular block, non-sustained ventricular tachycardia, and left ventricular ejection fraction. In the derivation sample, C-index (95% CI) of the model was 0.776 (0.711–0.842). In the external validation sample, the C-index was 0.800 (0.642–0.959) and calibration slope 1.082 (95% CI, 0.643–1.522). A 5-year estimated risk threshold ≥7% predicted 96.2% of LTVTA and net reclassified 28.8% of patients with LTVTA compared with the guidelines-based approach.

Conclusions

Compared to the current standard of care, this risk prediction model for LTVTA in laminopathies facilitated significantly the choice of ICD candidates.

Acknowledgement/Funding

AFM Téléthon