Cardiac Resynchronization Therapy for Failing Single Ventricle Physiology

We aimed to evaluate the mid-term outcomes of cardiac resynchronization therapy (CRT) in patients with single ventricle (SV), heart failure, and ventricular dyssynchrony, which leads to heart failure and poor outcomes.

We retrospectively reviewed patients with SV who underwent CRT at our institution between 2010 and 2024. Dyssynchrony was defined as QRS duration ≥130 ms and qualitative mechanical dyssynchrony between the main and rudimentary ventricles assessed by echocardiography and cine-angiography. Cardiac resynchronization therapy indications were based on acute haemodynamic studies (shortened QRS duration and increased peak dP/dt). The patients were divided into Groups G (CRT after bidirectional Glenn) and F (after Fontan completion). Haemodynamic parameters, NYHA class, brain natriuretic peptide, survival, Fontan completion rate, and hepatic function were analysed.

Group G included 9 and Group F included 11 patients. One year after CRT, the systemic ventricular ejection fraction improved in Groups G (30%-40%, P = .006) and F (30%-53%, P = .001), with corresponding increases in cardiac index and NYHA class. The median follow-up was 6.7 years (Group G) and 7.6 years (Group F). The 5-year survival rates were 89% and 82%, respectively. The Fontan completion rate was 76% at 5 years in Group G. In Group F, brain natriuretic peptide levels improved, hepatic function remained stable, and no protein-losing enteropathy was reported.

Cardiac resynchronization therapy improved systemic ventricular function and heart failure symptoms. Cardiac resynchronization therapy might be a viable therapeutic option for patients with SV, ventricular dyssynchrony, and heart failure.