P994Is post-shock pacing really needed in ICD patients? Preliminary results from the IMPLANTED registry

Abstract

Background: Post-shock pacing is considered a staple in current ICD programming. However, the real need for this option is still unknown. A sub-analysis of the SCDHeFT trial showed that, out of 153 total appropriate shocks, only 23.5% were followed by a post-shock pacing, and in only 5% of the cases the right ventricle was paced for more than 5 seconds. The aims of the present study were: to describe how much the post-shock pacing feature is used in clinical practice, to assess the incidence of postshock pacing in a “real world” population, and to identify clinical factors predicting the need for post-shock pacing. Methods: The IMPLANTED is a multicentric registry prospectively collecting all data regarding remote-monitored cardiac implantable devices from seven high-volume arrhythmia centers. For the present analysis, 1068 consecutive transvenous ICD recipients were analyzed (22.4% single-chamber, 25.5% dual-chamber, 52.1% CRTD). Post-shock programming after ICD implant was noted, and all appropriate shocks were checked through the remote monitoring in order to evaluate the rhythm after the shock (spontaneous vs. paced) and, in the case of paced rhythm, the time to recovery of spontaneous ventricular activity. Results: Out of 1068 total patients, 66.4% were male and mean age was 65±14 years. Median NYHA class was II and mean LVEF was 35±12%. 39.1% of all patients presented an ischemic cardiomyopathy, 45.1% presented a dilated idiopathic cardiomyopathy and 15.8% other types of heart disease. In 589 patients (55.2%) the post-shock pacing was turned on. The programmed post-shock pacing rate was 70 bpm in 78.8% of cases, <70 bpm in 18.8% of cases and >70 bpm in 2.4% of cases. Median programmed post-shock pacing duration was 10 seconds. During a median follow-up of 19 months, 122 ventricular arrhythmias were detected and shocked in 80 patients. A paced rhythm was documented in 53 (43.4%) events. A multivariate logistic analysis the following factors as clinical predictors of a paced rhythm after a shock: age (p=0.023), COPD (p=0.028), ischemic cardiomyopathy (p=0.002) and a paced rhythm prior to the shock (p<0.001). Conclusions: In a large, “real world”, dataset post-shock pacing is considered useful and therefore turned on by the physician in half of the ICD patients. Another half of those patients present a spontaneous rhythm after an appropriate shock. Age, COPD, ischemic cardiomyopathy, and the need for permanent pacing predict the usefulness of post-shock pacing.