A single implantable cardioverter-defibrillator shock unmasking an electrical storm of 389 ventricular tachycardia episodes triggering device therapies.

We describe the case of a patient with ischemic cardiomyopathy who presented the first implantable cardioverter-defibrillator (ICD) shock approximately 5 months after implantation. Device interrogation surprisingly revealed the occurrence of 389 ventricular tachyarrhythmia episodes terminated by asymptomatic antitachycardia pacing (ATP) except for the episode requiring shock. The present case of electrical storm highlights how contemporary tiered ATP schemes constitute a valuable but underused form of termination for ventricular tachyarrhythmias in ICD patients, reducing the number of painful shocks and their adverse consequences.