Immediate Impact of Successful Percutaneous Mitral Valve Commissurotomy on Echocardiographic Measures of Right Ventricular Contractility

Abstract

Functional analysis of the right ventricle cannot be reliably evaluated by conventional echocardiography, because of its complex geometry and load dependence of ejection phase indices. The Tei index, dP/dt, and myocardial acceleration during isovolumic contraction are parameters of right ventricular (RV) contractility unaffected by RV geometry. However, the effect of loading conditions on these parameters is controversial. The aim of this study was to examine how afterload reduction observed after percutaneous transverse mitral commissurotomy (PTMC) in patients with mitral stenosis affects these measures of RV contractility. Fifty-eight patients (mean age, 30.0 ± 8.3 years seven men, 52 women) with isolated rheumatic mitral stenosis, eight of whom had atrial fibrillation, were studied prospectively before and 24 to 48 hours after PTMC. Immediately after PTMC, mitral valve area increased from 1.0 ± 0.2 to 1.8 ± 0.3 cm(2) (P= .0001). There was a significant decrease in systolic pulmonary artery pressure from 50.2 ± 26.9 to 33.2 ± 12.3 mm Hg (P=.0001), a decrease in the RV Tei index from 0.5 ± 0.2 to 0.3 ± 0.2 (P= .0001), and an increase in RV dP/dt from 321.0 ± 59.9 to 494.6 ± 139.5 mm Hg/sec (P= .0001). RV myocardial acceleration during isovolumic contraction and systolic velocity at the lateral tricuspid annulus assessed by Doppler tissue imaging did not change. There were weak positive correlations among the Tei index, dP/dt, and systolic pulmonary artery pressure before PTMC (respectively, r= 0.39, r= 0.28, and P= .02, P= .05) but not afterward (respectively, r=0.17, r= 0.02, and P= .20, P= .90). This study suggests that RV dP/dt and Tei index are weakly load dependent, whereas myocardial acceleration during isovolumic contraction is unaffected by acute change in RV afterload.