Author + information
- Maurizio Gasparini, MD∗ ()
- ↵∗Electrophysiology and Pacing Unit, Humanitas Research Hospital, IRCCS, Via Manzoni 56, 20089 Rozzano (MI), Italy
Powell et al. (1) reported interesting data on survival after shock therapy in a large cohort of patients enrolled in the ALTITUDE study. The analysis showed that following a first implantable cardioverter-defibrillator (ICD) shock delivered for ventricular episodes or atrial fibrillation, there is an increased risk of death. The same effect is not found when the shock is delivered for a benign rhythm. Powell et al. (1) discussed their results in the context of MADIT-RIT (Multicenter Automatic Defibrillator Implantation Trial Reduce Inappropriate Therapy) (2) data assessing whether the 2 results are contradicting and concluded that “combining the results of the 2 studies, one could conclude that unnecessary ATP [antitachycardia pacing] may increase mortality, while unnecessary shocks for sinus tachycardia, SVT [supraventricular tachycardia], or noise/artifact/oversensing does not appear to affect long-term survival.” Our recently published experience (3)—not available at the time of this publication—confirms the finding reported by Powell et al. (1) that the inappropriate shock itself does not appear to be associated with a worst outcome. With this further confirmation in a real-life population, the question on the possible explanation for the reduced mortality observed in the MADIT-RIT study still remains open.
In the MADIT-RIT control arm, ATP therapy was delivered to treat slow tachycardia, regardless of patients' previous history of arrhythmia; this, associated with a lost to follow-up rate greater than 11%, may potentially have had an effect on the reported mortality data.
Despite the association of unnecessary ATP therapy with a worse prognosis cannot be excluded for ATP therapies delivered to treat slow rhythms, it would be interesting to have details on the programming zones of patients who died in the ALTITUDE analysis. We believe that inappropriate and unnecessary aggressive ICD programming may represent 1 of the key factors for negative outcome of patients implanted with ICDs.
- American College of Cardiology Foundation