Foregoing ICD implantation in patients presenting with ventricular tachycardia: is catheter ablation alone sufficient?

Ventricular tachycardia (VT) in the setting of structural heart disease (SHD) and a reduced ejection fraction (EF) of ≤35% is commonly treated by insertion of an implantable cardioverter-defibrillator (ICD). While the strategy of secondary prevention reduces mortality, the presence of an ICD has no impact on recurrent episodes of VT. Hence, antiarrhythmic drug therapy is frequently established in order to prevent future arrhythmic events. Use of potent drugs such as amiodarone is hampered by a multitude of side effects, often leading to drug discontinuation by the patient. Since VT in patients with SHD is commonly due to macro-re-entry within the ventricles, catheter ablation has become an attractive means to terminate VT acutely (Table 1). The first prospective randomized trial, SMART VT, demonstrated that patients with coronary artery disease (CAD) presenting with aborted sudden cardiac death, syncope, or unstable VT/ventricular fibrillation (VF) benefit from catheter ablation, resulting in a significant reduction of appropriate ICD shocks. There was also a trend towards a lower number of deaths in the catheter ablation group. A second prospective randomized multicentre trial, VTACH, examined the role of catheter ablation inpatientswithunderlyingCADpresentingwith afirstepisodeof stable VT. Again, a significant reduction in appropriate ICD therapy was seen. Hence, catheter ablation is a viable option in patients with CAD presenting with VT and is supported by the highest degree of evidence as outlined above. However, currently patients are likely to undergo ICD implantation irrespective of the outcome of catheter ablation based on a class I recommendation as set forth in current guidelines. In addition, a significant number of patients may present with arrhythmia recurrence following successful catheter ablation (SMART VT, 12% of patients during 22.5+5.5 months of follow-up; VTACH, 50% of patients with appropriate ICD intervention during 22.5+9.0 months of follow-up). Of interest, in VTACH, those patients with CAD and only mild to moderately reduced EF (.30%) benefited most from catheter ablation. In this context, the study of Maury et al. analysed the outcome of patients with SHD and a reduced EF .30% undergoing catheter ablation for stable, well-tolerated VT without subsequent implantation of an ICD as recommended by current guidelines. Data were collected retrospectively from eight European centres. A total of 166 patients (84% male) met the selection criteria and were included in the analysis. The majority of patients suffered from CAD (55%), while nearly one-third of patients had underlying non-ischaemic cardiomyopathy (19%) or arrhythmogenic right ventricular dysplasia (12%). A group of 378 patients with similar diagnoses undergoing catheter ablation of VT followed by ICD placement served as a nonmatched control group. Upon a mean follow-up period of 32+27 months, all-cause mortality was 12%,whileonly4/166 (2.4%)patients died suddenly. In the control group, all-cause mortality was identical at 12%. The authors concluded that patients with SHD and mild to moderately suppressed EF .30% have a low risk of dying from an arrhythmic cause and, based on their retrospective data, a prospective randomized multicentre trial would be warranted comparing a strategy of catheter ablation with and without subsequent implantation of an ICD. While the time would be right to perform such a trial, there are several issues that need to be discussed when interpreting the data presented by Maury and colleagues. First, this was a retrospective study analysing data from a mixed patient cohort presenting with a variety of underlying cardiac pathologies with significant differences in the natural course of disease progression. Secondly, there was no standardized protocol that was followed during catheter ablation. Thirdly, none of the patients received an ICD. This is contrary to current international guidelines that list placement of an ICD as a