Effectiveness of single- vs dual-coil implantable defibrillator leads: An observational analysis from the SIMPLE study.

INTRODUCTION: Dual-coil leads (DC-leads) were the standard of choice since the first nonthoracotomy implantable cardioverter/defibrillator (ICD). We used contemporary data to determine if DC-leads offer any advantage over single-coil leads (SC-leads), in terms of defibrillation efficacy, safety, clinical outcome, and complication rates. METHODS AND RESULTS: In the Shockless IMPLant Evaluation study, 2500 patients received a first implanted ICD and were randomized to implantation with or without defibrillation testing. Two thousand and four hundred seventy-five patients received SC-coil or DC-coil leads (SC-leads in 1025/2475 patients; 41.4%). In patients who underwent defibrillation testing (n = 1204), patients with both lead types were equally likely to achieve an adequate defibrillation safety margin (88.8% vs 91.2%; P = 0.16). There was no overall effect of lead type on the primary study endpoint of "failed appropriate shock or arrhythmic death" (adjusted HR 1.18; 95% CI, 0.86-1.62; P = 0.300), and on all-cause mortality (SC-leads: 5.34%/year; DC-leads: 5.48%/year; adjusted HR 1.16; 95% CI, 0.94-1.43; P = 0.168). However, among patients without prior heart failure (HF), and SC-leads had a significantly higher risk of failed appropriate shock or arrhythmic death (adjusted HR 7.02; 95% CI, 2.41-20.5). There were no differences in complication rates. CONCLUSION: In this nonrandomized evaluation, there was no overall difference in defibrillation efficacy, safety, outcome, and complication rates between SC-leads and DC-leads. However, DC-leads were associated with a reduction in the composite of failed appropriate shock or arrhythmic death in the subgroup of non-HF patients. Considering riskier future lead extraction with DC-leads, SC-leads appears to be preferable in the majority of patients.

Sedation strategies for defibrillation threshold testing: safety outcomes with anaesthesiologist compared to proceduralist-directed sedation: an analysis from the SIMPLE study.

Aims: No standard practice exists with respect to anaesthesiologist-directed sedation (ADS) vs. sedation by proceduralist (PDS) for defibrillation threshold (DT) testing. We aimed to evaluate adverse events and safety outcomes with ADS vs. PDS for DT testing. Methods and results: A post hoc analysis of the Shockless Implant Evaluation (SIMPLE) study was performed among the 1242 patients who had DT testing (624 ADS and 618 PDS). We evaluated both intraoperative and in-hospital adverse composite events and two safety composite outcomes at 30-days of the main trial. Propensity score adjusted models were used to compute odds ratio (OR) and 95% confidence interval (CI) to evaluate the association between adverse and safety outcomes with method of sedation and independent predictors for use of ADS. Compared to PDS, patients who received ADS were younger (62 ± 12 years vs. 64 ± 12 years, P = 0.01), had lower ejection fraction (left ventricular ejection fraction 0.31 ± 13 vs. 0.33 ± 13, P = 0.03), were more likely to receive inhalational anaesthesia, propofol, or narcotics (P < 0.001, respectively) and receive an arterial line (43% vs. 8%, P = <0.0001). Independent predictors for ADS sedation were presence of coronary artery disease (OR 1.69, 95% CI 1.0-2.72; P = 0.03) and hypertrophic cardiomyopathy (OR 2.64, 95% CI 1.19-5.85; P = 0.02). Anaesthesiologist directed sedation had higher intraoperative adverse events (2.2% vs. 0.5%; OR 4.47, 95% CI 1.25-16.0; P = 0.02) and higher primary safety outcomes at 30 days (8.2% vs. 4.9%; OR 1.72 95% CI 1.06-2.80; P = 0.03) and no difference in other outcomes compared to PDS. Conclusion: Proceduralist-directed sedation is safe, however, this could be result of selection bias. Further research is needed.

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.