A randomized comparison of defibrillation thresholds in the right ventricular outflow tract versus right ventricular apex

EHRA expert consensus statement and practical guide on optimal implantation technique for conventional pacemakers and implantable cardioverter-defibrillators: endorsed by the Heart Rhythm Society (HRS), the Asia Pacific Heart Rhythm Society (APHRS), and the Latin-American Heart Rhythm Society (LAHRS)

With the global increase in device implantations, there is a growing need to train physicians to implant pacemakers and implantable cardioverter-defibrillators. Although there are international recommendations for device indications and programming, there is no consensus to date regarding implantation technique. This document is founded on a systematic literature search and review, and on consensus from an international task force. It aims to fill the gap by setting standards for device implantation.

Apical versus Non-Apical Lead: Is ICD Lead Position Important for Successful Defibrillation?

INTRODUCTION

We aim to compare the acute and long-term success of defibrillation between non-apical and apical ICD lead position.

METHODS AND RESULTS

The position of the ventricular lead was recorded by the implanting physician for 2,475 of 2,500 subjects in the Shockless IMPLant Evaluation (SIMPLE) trial, and subjects were grouped accordingly as non-apical or apical. The success of intra-operative defibrillation testing and of subsequent clinical shocks were compared. Propensity scoring was used to adjust for the impact of differences in baseline variables between these groups. There were 541 leads that were implanted at a non-apical position (21.9%). Patients implanted with a non-apical lead had a higher rate of secondary prevention indication. Non-apical location resulted in a lower mean R-wave amplitude (14.0 vs. 15.2, P < 0.001), lower mean pacing impedance (662 ohm vs. 728 ohm, P < 0.001), and higher mean pacing threshold (0.70 V vs. 0.66 V, P = 0.01). Single-coil leads and cardiac resynchronization devices were used more often in non-apical implants. The success of intra-operative defibrillation was similar between propensity score matched groups (89%). Over a mean follow-up of 3 years, there were no significant differences in the yearly rates of appropriate shock (5.5% vs. 5.4%, P = 0.98), failed appropriate first shock (0.9% vs. 1.0%, P = 0.66), or the composite of failed shock or arrhythmic death (2.8% vs. 2.3% P = 0.35) according to lead location.

CONCLUSION

We did not detect any reduction in the ICD efficacy at the time of implant or during follow-up in patients receiving a non-apical RV lead.

Predictors of high defibrillation threshold in patients with implantable cardioverter-defibillator using a transvenous dual-coil lead

BACKGROUND

Defibrillation testing (DT) is considered a standard procedure during implantable cardioverter-defibrillator (ICD) implantation. However, little is known about the factors that are significantly related to patients with high defibrillation threshold (DFT) using the present triad system.

METHODS AND RESULTS

We examined 286 consecutive patients who underwent ICD implantation with a transvenous dual-coil lead and DT from December 2000 to December 2011. We defined patients who required 25 J or more by the implanted device as the high DFT group, and those who required less than 25 J as the normal DFT group. For each patient, assessment parameters included underlying disease, comorbidities, NYHA functional class, drugs, and echocardiographic measures. The high DFT group consisted of 12 patients (4.2%). Multivariate analysis identified 3 independent predictors for high DFT: atrial fibrillation (odds ratio (OR) 4.85, 95% confidence interval (CI) 1.24-22.33, P=0.023), hypertension (OR 4.01, 95% CI 1.08-15.96, P=0.039), thickness of interventricular septum (IVS) >12 mm (OR 4.82, 95% CI 1.17-20.31, P=0.030).

CONCLUSIONS

Atrial fibrillation, hypertension and IVS hypertrophy were significantly associated with high DFT. Identification of such patients could help to lower the risk of complications with DT.

A randomized study of defibrillator lead implantations in the right ventricular mid-septum versus the apex: the SEPTAL study

INTRODUCTION

The study was designed to evaluate the feasibility and performance of right ventricular (RV) mid-septal versus apical implantable defibrillator (ICD) lead placement.

METHODS AND RESULTS

SEPTAL is a randomized, noninferiority trial, which randomly assigned patients to implantation of ICD leads in the RV mid-septum versus apex, with a primary objective of comparing the implant success rate of implant at each site, based on strict electrical predefined criteria. We also compared the (1) pacing lead characteristics, (2) rates of appropriate and inappropriate ICD therapies, and (3) all-cause mortality between the 2 sites at 1 year. The trial enrolled 215 patients (mean age = 59.7 ± 12.4 years, mean LVEF = 34.0 ± 14.2%, 84.2% men), of whom 148 (68.8%) presented with ischemic heart disease. The ICD indication was primary prevention in 117 patients (54.4%). The lead was successfully implanted in 96/107 patients (89.7%) assigned to the RV mid-septum, and in 99/108 (91.7%) assigned to the apex (ns). The 1-year rate of lead-related adverse events was similar in both groups. A total of 8 first inappropriate ICD therapies (7.9%) were delivered in the RV mid-septal group, versus 8 (7.8%) in the apical group (ns), while first appropriate therapies were delivered to 22 (21.4%) and 24 patients (23.8%), respectively (ns). All-cause mortality was 7.9% in the RV mid-septal versus 2.9% in the RV apical group (ns).

CONCLUSION

This study confirmed the technical feasibility and noninferior performance of ICD leads implanted in the RV mid-septum versus the apex.

Subacute cardiac perforations associated with active fixation leads

AIMS

Having several recently published reports on increased rate of cardiac perforation with some lead models as background, we assess the relation between cardiac perforations and models of leads used.

METHODS AND RESULTS

All pacing and defibrillation leads implantations between 1 January 2007 and 31 March 2008 were analysed retrospectively. There were 2247 leads implanted in 1419 patients aged 67.6 +/- 14.1, 1200 (53%) active and 1047 (47%) passive fixation leads. Cardiac perforation occurred in eight patients (0.5%). The number of perforations does not differ significantly between the pacemaker and implantable cardioverter defibrillator implantations (five and three cases, respectively, P = 0.13). All perforations were associated with the active fixation leads implantation (8 vs. 0, P < 0.01). Only four models of leads were associated with perforations, but the risk of their use was not statistically significantly increased, when compared with other active fixation leads placed in the adequate position.

CONCLUSIONS

The incidence of cardiac perforation related to pacing and defibrillation leads is low. The use of active fixation leads is associated with an increased risk of cardiac perforation. We did not find any correlation between the perforation rate and any particular model of the implanted lead.