75Internal cardioverter defibrillator follow up data of out of hospital cardiac arrest survivors within a tertiary centre in the UK

Abstract

Background: A significant proportion of the out of hospital cardiac arrest (OOHCA) population go on to receive implantable cardioverter defibrillators (ICDs). Research supports favourable morbidity and mortality benefits of this intervention, particularly in the prevention of arrhythmic deaths. Literature suggests high rates of ICD therapy following implantation for secondary prevention, particularly in those requiring an ICD following a primary arrhythmia, but there is little data surrounding when these therapies occur. Methods: We performed a retrospective review of case notes of 217 OOHCA patients undergoing an immediate invasive coronary strategy at our institution between 11th October 2012 and 20th November 2015. Evaluation of the follow-up data of each device was carried out in order to obtain event rates and time to first appropriate therapy. Results: Of the 217 OOHCA cases, 130 (59.9%) cases were attributed to an acute coronary occlusion, with 22 (10%) cases identified as having a primary arrhythmia as the cause of cardiac arrest. Following their arrest, 46 (21.2%) of the 217 patients received an ICD, 16 (34.8%) of which were within the primary arrhythmia population. The types of devices implanted included 32 dual-chamber ICDs, 7 single chamber trans-venous ICDs, 5 CRT-Ds and 2 S-ICDs. 25 of the 47 (53.3%) were on remote monitoring. To date, 99 (45.6%) patients died during follow-up, five of which had an ICD in-situ, equating to 10.9% of the ICD population. Of the ICD cohort, six (13.0%) received ICD therapy, with two of this subset (33.3%) having a primary arrhythmia diagnosis as the cause for their arrest. The median time to first therapy was 320 days (45 - 1417 days). All patients received appropriate ICD therapy during follow-up, with one receiving an additional inappropriate therapy for AF. A total of 14 therapies were deployed across all six patients. One patient presented with VT storm 737 days post ICD implantation requiring VT ablation. Despite ICD implantation and appropriate therapy, three (50%) died, all of whom were part of the non-arrhythmic population. Conclusions: A significant proportion of out of hospital cardiac arrests are due to primary arrhythmias, of which most go on to receive an ICD. This data supports ICD trial data, that appropriate therapy rates in this secondary prevention group are high, with variable times to first event rates. Mortality in this cohort of patients remains high with five of the 46 ICD patients dying during the follow up period.