Ventricular Apical Pacing for Ventricular Tachycardia Storm in a Patient With Midventricular Obstructive Hypertrophic...

A 74-year-old woman with midventricular obstructive hypertrophic cardiomyopathy complicated by apical aneurysm and sustained ventricular tachycardia (VT) was referred to our hospital, where she underwent catheter ablation and implantable cardioverter-defibrillator (ICD) placement.

She was readmitted 1 year later with VT storm triggering frequent ICD shocks. Antiarrhythmic drugs and repeat ablation were ineffective. We used the ICD to reduce her intraventricular pressure gradient via atrioventricular sequential right ventricular apical pacing. The pressure gradient decreased from 53 to 13 mm Hg, and VT was completely suppressed simultaneously, with no further incidents of ICD therapy for 22 months.

Stretch-activated channels from mechanical stimuli of intracavitary pressure overload were considered a possible mechanism of the VT storm. Because a substantial proportion of patients with midventricular obstruction (MVO) already meet the criteria for ICD implantation, switching from backup mode to active pacing mode can be a simple therapeutic option in patients with VT.

In some patients with MVO, apical pacing from an ICD may be antiarrhythmic for ventricular arrhythmias as well as beneficial for hemodynamics. Given that a substantial proportion of patients with MVO already meet primary or secondary criteria for transvenous ICD implantation, a switch from backup to active pacing mode can be a simple therapeutic option in many patients.