Outcomes of cardiac resynchronization therapy in adults with congenital heart disease and heart failure with reduced ejection fraction.

BACKGROUND

There are limited data about the role of cardiac resynchronization therapy (CRT) in adults with congenital heart disease (CHD) and heart failure with reduced ejection fraction (HFrEF).

OBJECTIVE

The objectives of this study were (1) to assess the relationship between CRT and clinical outcomes (all-cause mortality and cardiovascular events) and (2) to assess temporal changes in clinical indices of disease severity (New York Heart Association [NYHA] functional class, peak oxygen consumption, N-terminal pro-B-type natriuretic peptide, and left ventricular ejection fraction) post-CRT.

METHODS

This is a retrospective study of adults with CHD, biventricular circulation, systemic left ventricle, and HFrEF who received CRT at Mayo Clinic (2003-2023). Clinical indices of disease severity were assessed pre-CRT and 1-year post-CRT. We defined a CRT responder as a patient with an absolute increase in left ventricular ejection fraction ≥10% and an improvement in NYHA functional class by ≥1 unit post-CRT. Intensity of heart failure therapy was assessed using the guideline-directed medical therapy (GDMT) score.

RESULTS

Of the 327 patients with CHD and HFrEF, 105 (32%) received CRT (mean age 51 ± 15 years; 72 (68% men). CRT was associated with a 24% decrease in mortality (adjusted hazard ratio [HR] 0.76; 95% confidence interval [CI] 0.51-0.97) and a 21% decrease in cardiovascular events (adjusted HR 0.79; 95% CI 0.63-0.94). Of the 105 patients, 71 (68%) were CRT responders. Higher GDMT score was associated with greater odds of CRT response (adjusted odds ratio 1.28; 95% CI 1.04-1.47). CRT responders had a greater temporal improvement in NYHA functional class, peak oxygen consumption, N-terminal pro-B-type natriuretic peptide level, and a lower risk of cardiovascular events (unadjusted HR 0.73; 95% CI 0.47-0.99).

CONCLUSION

These data highlight the clinical benefits of CRT and GDMT for the management of HFrEF in CHD and support the use of these therapies in this population.