The wearable cardioverter defibrillator (WCD) is used for temporary protection of patients deemed to be at high risk for sudden death. There is limited experience regarding the clinical development of patients with tachymyopathy. We aimed to evaluate the clinical development of tachymyopathy patients protected with a WCD in a single-center non-randomized patient cohort.

We fitted 130 consecutive patients deemed to be at high risk for ventricular tachyarrhythmias with the WCD. Of these, 20 patients (15%) presenting with newly diagnosed heart failure in the setting of rapidly conducted atrial fibrillation/flutter were suspected to suffer from tachymyopathy. The control group consisted of the remaining 110 patients with other indications for WCD therapy. LVEF increased by more than 10% in 13/20 (65%) tachymyopathy patients compared to 40/110 (36%) patients in the control population (p = 0.01). Similarly, BNP levels decreased in 15/20 (75%) tachymyopathy patients compared to 41/110 (37%) in the control group (p = 0.05). ICD implantation rates were lower in the tachymyopathy group (3/20) compared to the control population (40/110; p = 0.04). On further follow-up (mean 12 ± 8 months), patients with suspected tachymyopathy had no sustained ventricular arrhythmias. Compared to 5/110 patients in the control group, no tachymyopathy patient died.

Most of the patients with suspected tachymyopathy have a favorable clinical outcome. The WCD is useful for temporary protection while LV function recovers.