Stroke after implantable cardioverter-defibrillator shocks in patients with heart failure

Abstract

Abstract Introduction In patients with atrial fibrillation (AF), an elevated risk of stroke has been demonstrated in the first days after successful electrical cardioversion of AF. Shock therapies delivered by implantable cardioverter-defibrillators (ICD) often result in termination of AF, potentially increasing the risk of stroke in those patients. However, the association between ICD shocks and the risk of stroke in patients with AF is unknown. Purpose To define whether there is any temporal association between ICD shocks and strokes in remotely monitored patients with heart failure (HF) and AF. Methods The clinical data of patients enrolled in the remote monitoring (RM) programme after implantation of an ICD were obtained from the single-centre COMMIT-HF registry. The data regarding the occurrence of the first stroke after inclusion to the registry were obtained (based on the International Classification of Diseases codes I63-I64) from the healthcare provider. The RM data of all patients were obtained from the investigator-initiated and -maintained registry of RM, which summarizes all major findings in remotely monitored patients in our department. Each patient with a stroke had the RM history evaluated for the period of the prior 30 days, with emphasis on the last 10 days preceding stroke. Results During the period between 2011 and 2020, 1,299 patients with detailed clinical characteristics were enrolled in the RM programme, and their clinical data are summarized in Table 1.There were 33.4% patients with AF at baseline, and AF de novo was identified during follow-up in further 14.0% of patients. Among patients without and with AF at baseline, respectively 30.9% and 34.1% received any ICD shocks during follow-up (p=NS). In 38.2% of patients without AF at baseline, who developed de novo AF, at least one shock occurred. The median follow-up was 4.4 years, and the incidence of stroke was 45 (3.5%) in the studied population, with a rate of stroke of 2.8% (25/865) in patients without AF at baseline and 4.6% (20/434) in patients with AF (p=NS), as presented in Figure 1. The median (Q1-Q3) time from ICD implantation to stroke was 1.5 (0.8-2.5) years. Strokes occurring less than 10 days from ICD shock were noted in only two patients (0.5% of patients with any ICD shock) and both occurred within 24 hours from the shock. In the first case, the device appropriately terminated ventricular tachycardia which degenerated to ventricular fibrillation after antitachycardia pacing, and in the second case, a shock therapy was delivered due to VF in a 59-year-old male with HF and concomitant paroxysmal AF, who was on chronic treatment with warfarin. Conclusions Our findings indicate an overall low risk of stroke associated with ICD shocks, both in patients with and without AF.Baseline population characteristicsAnalysed population flowchart