131-08: Shock Efficacy and mortality of patients with single and dual coil electrodes: A subgroup analysis of the NORDIC ICD trial

Abstract

Purpose: The NORDIC ICD trial was designed to test the hypothesis that defibrillation (DF) testing omission during implantable cardioverter-defibrillator (ICD) implantation would not result in an inferior shock efficacy during follow-up. In the present substudy, we assessed whether the first shock efficacy (FSE) would be similar between patients who received a single coil (SC) or dual coil (DC) electrode. Method(s): Between February 2011 and July 2013, 1077 patients were randomly assigned (1:1) to first time ICD implantation with (n = 540) or without (n = 537) DF testing. The electrode configuration (SC or DC) had to be determined before randomisation. The primary endpoint was the average FSE for all true ventricular tachycardia and fibrillation (VT/VF) episodes during follow-up. Summary: Of the 1077 patients included in the trial, 1067 received an ICD with a SC electrode in 516 (48.4%) and a DC electrode in 551 (51.6%). DC electrodes were more often used in patients with higher NYHA class (p , 0.001), atrial fibrillation (p = 0.002), hypertension (p = 0.001), renal failure (p , 0.001), ischaemic heart disease (p = 0.045) and CRT devices (p , 0.001). Using a mixed logistic regression model, the FSE of all episodes was 92.6% with SC and 97.8% with DC electrodes (OR = 3.6, 95% CI [0.99, 13.2]; p = 0.052). The adjustment for DF testing, LVEF >= 30% and diuretic medication (other than spironolactone) increased the OR to 4.3 (95% CI [1.9, 9.8]; p , 0.001). Intra-operative procedural characteristics and mortality were also compared between the electrode types, and the results will be presented at the meeting. Conclusion(s): Use of DC electrodes appears to be preferred in patients with advanced heart failure and CRT devices. DC electrodes provide a substantially higher first shock efficacy during follow-up.