Recovery of the systolic time intervals by coenzyme Q10 in patients with a load-induced cardiac dysfunction.

In patients with a load-induced cardiac dysfunction (LCD), the left ventricular (LV) stroke work is supernormal at rest, but then becomes subnormal during handgrip (HG). The LCD usually occurs in children with the mitral valve prolapse (MVP). Our catheterization study revealed that the end-diastolic pressure (EDP) of both ventricles was elevated in LCD patients. In this study, the LV and right ventricular (RV) systolic time (ET) were measured by echocardiograms. The mitral inflow peak velocities, E and A, were also measured by the pulsed Doppler method. Subjects were divided into four groups, each consisting of 16 individuals: group 1, normal children; group 2, LCD patients; group 3, recovered children from LCD, the same individuals as group 2, but after coenzyme Q10 (CoQ) therapy; and group 4, asymptomatic children with MVP. In group 2, the mean PEP and PEP/ET were significantly smaller and the peak A velocity was significantly larger than in groups 1, 3 and 4. Among groups 1, 3 and 4, no intergroup differences were found regarding the PEP/ET and A. In LCD patients, a depressed inotropic state of the myocardium may result in a high EDP due to the Frank-Starling mechanism, and such a high EDP may then cause STI changes and a large A velocity. CoQ may also return abnormal STIs in LCD patients to normal, probably by improving the inotropic state and, as a consequence, reducing the high EDP of the LV and RV to a normal level.