Right Ventricular Pump Efficiency in Secundum-Type Atrial Septal Defect

A well-functioning cardiopulmonary system, which works as a pump, should generate adequate stroke volume with as little stroke work as possible. We propose a new composite parameter, right ventricular (RV) pump efficiency (η) = left ventricular stroke volume / right ventricular stroke work, to describe this idea in a volume overload population with secundum-type atrial septal defect (ASD).

We consecutively enrolled 50 patients with secundum-type ASD to investigate the relationship between right-sided volume overload and RV pump efficiency. Sixteen patients with a pulmonary to systemic flow ratio (Qp/Qs) > 1.5 underwent implantation of an occluder. The paired t test was used to compare RV pump efficiency before and after ASD closure.

RV pump efficiency was inversely correlated with Qp/Qs and was 60 ± 20‰ · mmHg^-1 at Qp/Qs = 1. After ASD closure, RV volume, ejection fraction and free wall strain all significantly decreased, while RV pump efficiency significantly increased from 27.4 ± 13.6 to 63.9 ± 20.4‰ · mmHg^-1.

RV pump efficiency can superiorly reflect the chronicity and severity of secundum-type ASD.