Suitability of cardiac resynchronisation therapy in patients with Fontan circulation and congenitally corrected transposition of the great arteries

Cardiac resynchronisation therapy (CRT) is a well-recognised treatment in systolic heart failure. There is limited evidence in congenital patients with univentricular hearts or systemic right ventricles. In 2014 PACES/HRS published a consensus statement recommending CRT if ventricular ejection fraction (EF)≤35%, QRS duration≥150ms (with RBBB in systemic RV), NYHA II-IV and ventricular dilatation. The incidence of patients meeting these criteria in whom CRT is possible is not known. Retrospective analysis of 203 patients with a univentricular Fontan circulation and 55 patients with ccTGA under specialist ACHD care. Univentricular functional data was available for 194 (96%), 10 (5%) having EF≤35%. QRS duration was available for 190 (94%) and was ≥150ms in five (3%). EF data was available for 54 (98%) ccTGA patients, and was ≤35% in 6 (11%). QRS duration was ≥150ms in 13 (26%). Only four patients fulfilled recommendations and two received CRT. Only a small proportion of patients with single ventricles or ccTGA meet the criteria for CRT. In many of these patients there are significant anatomical barriers to CRT which limit its use in this population. The decision to implant CRT in complex ACHD requires discussion in a combined ACHD electrophysiology surgical multidisciplinary meeting and close collaboration with patients.