Cardiac resynchronization therapy: A novel adjunct to the treatment and prevention of systemic right ventricular failure

Abstract

This study aimed to evaluate the technical feasibility and hemodynamic benefit of cardiac resynchronization therapy (CRT) in patients with systemic right ventricle (RV). Patients with a systemic RV are at high risk of developing heart failure. Cardiac resynchronization therapy may improve RV function in those with electromechanical dyssynchrony. Eight patients (age 6.9 to 29.2 years) with a systemic RV and right bundle-branch block (n = 2) or pacing from the left ventricle (LV) (n = 6) with a QRS interval of 161 +/- 21 ms underwent CRT (associated with cardiac surgery aimed at decrease in tricuspid regurgitation in 3 of 8 patients) and were followed-up for a median of 17.4 months. Change from baseline rhythm to CRT was accompanied by a decrease in QRS interval (-28.0%, p = 0.002) and interventricular mechanical delay (-16.7%, p = 0.047) and immediate improvement in the RV filling time (+10.9%, p = 0.002), Tei index (-7.7%, p = 0.008), estimated RV maximum +dP/dt(+45.9%, p = 0.007), aortic velocity-time integral (+7.0%, p = 0.028), and RV ejection fraction by radionuclide ventriculography (+9.6%, p = 0.04). The RV fractional area of change increased from a median of 18.1% before resynchronization to 29.5% at last follow-up (p = 0.008) without a significant change in the end-diastolic area (+4.0%, p = NS). The CRT yielded improvement in systemic RV function in patients with spontaneous or LV pacing-induced electromechanical dyssynchrony and seems to be a promising adjunct to the treatment and prevention of systemic RV failure.