Successful hybrid cardiac resynchronization therapy in a patient with failing systemic right ventricle and significant tricuspid regurgitation in transposition of the great arteries after atrial switch procedure according to Mustard.

Background: Patients with a systemic right ventricle (sRV) in the context of transposition of the great arteries (TGA) late after atrial switch are prone to heart failure. Complications like tricuspid valve regurgitation (TR) can further aggravate sRV dysfunction. Tricuspid valve regurgitation is usually secondary to annular dilatation and restriction. Criteria for cardiac resynchronization therapy (CRT) in this patient group are not well defined and should be considered on a case-by-case basis.

Case summary: We present a case of a 42-year-old male with sRV failure and TR in the context of TGA after atrial switch. Patient had progressive reduction in exercise capacity. Electrocardiogram showed a wide QRS complex (right bundle branch block configuration). Echocardiography showed significant TR and signs of electromechanical dyssynchrony of the failing sRV with severely reduced systolic function. He underwent heart catheterization and invasive haemodynamic evaluation to assess the potential benefit of CRT. During sequential atrial-sRV pacing, 20% increase in Dp / Dt was measured, suggesting that he would be a CRT responder. Concomitant angiography showed no baffle leakage nor obstructive coronary artery disease. Hybrid CRT-defibrillator implantation resulted in successful resynchronization and improved sRV function, reduced TR and better exercise capacity.

Discussion: Invasive haemodynamic contractility evaluation can help assess the potential benefit of CRT in patients with systemic right ventricular failure in the context of transposition of TGA after atrial switch. Successful CRT can result in improved sRV function, reduced TR and improved exercise capacity.