Double-device therapy in a patient with long QT syndrome.

A 26-year-old man with long QT syndrome (LQTS) underwent subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation. The patient exhibited sinus bradycardia relative to his age. The heart rate decreased, and the QT interval became longer with the administration of β-blockers, the first-line therapy for LQTS. The patient experienced frequent S-ICD discharges. Subsequently, a single-chamber pacemaker was implanted, and the 12-lead electrocardiogram showed atrial pacing and ventricular sensing at 60 beats per minute with a shorter QTc interval. After converting to "double-device therapy," the patient did not experience any ventricular arrhythmia events.