Clinical implication of detected tachyarrhythmias in patients with implantable cardioverter defibrillators

Abbas and colleagues analyzed a substantial cohort of implantable cardioverter-defibrillator recipients enrolled in landmark clinical trials.1 They demonstrated that the presence of atrial fibrillation (AF) and ventricular tachyarrhythmia (VT), as detected by the implanted devices, correlated with future exacerbation of congestive heart failure and mortality. Several concerns have been raised. In the authors' study, the presence of AF was not linked to mortality.1 In the ACALM registry study, the prognostic difference between AF and sinus rhythm did not achieve statistical significance until the 5-year observation mark.2 Moreover, in previous literature, not only the presence of AF but also its burden, such as the daily percentage of time spent in AF and the maximal AF episode duration, were associated with future adverse outcomes, including cardiovascular hospitalization, ischemic stroke, and mortality.3 The discrepancy between the authors' findings and those of previous literature warrants further discussion. Based on their findings, the authors recommended early intervention for these tachyarrhythmias in patients receiving implantable cardioverter defibrillators, if applicable.1 However, patients with advanced heart failure often complicate these tachyarrhythmias due to their impaired myocardium.4 Such pump failure is also associated with mortality and morbidity. Thus, addressing arrhythmia alone may not necessarily improve clinical outcomes. In a previous study involving individuals with implantable cardioverter defibrillators, aggressive ablation for VT reduced the incidence of appropriate defibrillation but did not reduce mortality.5 Other considerations, such as optimal patient selection for aggressive ablation and more intensive therapies, including durable ventricular assist devices, should be discussed.