Expanding Applications of Defibrillators and Cardiac Resynchronization Therapy to Include Adult Congenital Heart Disease

Atrial redirection surgery, brought into common use by Mustard’s modification of the Senning procedure, transformed the natural history of dextro-transposition of the great arteries (dTGA) from a 90% one year mortality to a 90% 1 year survival(1). Although rendering the infant acyanotic with excellent functional capacity, the morphological right ventricle(sRV) is required to support the systemic circulation. The sRV faces substantial pressure overload resulting in a high incidence of late ventricular failure(2). This prompted an evolution to a more physiologically acceptable correction in the form of the arterial switch or Jatene operation(3). The arrhythmias and heart failure that usually manifest by the second decade of life in patients after atrial redirection surgery pose a challenge to management. Apart from the progressive sRV dysfunction and heart failure, sinus bradycardia commonly arises because of surgical disruption to the sino-atrial node blood supply warranting early pacemaker implantation (4). The incidence of tachyarrythmias, most notably atrial flutter and fibrillation, may be related to ventricular dysfunction or as a consequence of atrial scarring following surgery. Ventricular tachycardia (VT) and fibrillation (VF) have been documented on holter monitoring in various long term studies and the incidence of sudden cardiac death (SCD) ranges between 2-11%(5). Cardiac resynchronization with a biventricular implantable cardioverter-defibrillator (ICD) therefore poses an attractive option particularly as a bridge to transplantation in this group of patients. We examine the challenges in terms of the anatomical constraints in a group of consecutive patients with surgically corrected TGA(6;7).