Maternal left ventricular performance during bicycle exercise

Abstract

Over the last few years, more women are exercising during pregnancy. Although many studies have examined left ventricular (LV) function during exercise in nonpregnant subjects, to date there is minimal data available on the LV response in the pregnant patient exercising at a high level of intensity during the second half of pregnancy. Pregnancy has been compared to a state of volume overload resulting in an increase in LV size without significant hypertrophy of the LV walls. 1 This increase in radius-to-wall thickness ratio may be viewed as detrimental to LV emptying, because wall stress is directly proportional to this ratio. 2 To offset this change in LV shape, vascular resistance and mean arterial blood pressure are significantly reduced during pregnancy. 2 We hypothesized that strenuous exercise during the second half of pregnancy could result in an afterload mismatch. This study examines LV size and function during vigorous stationary bicycle exercise performed in an erect position in 16 fit, pregnant women using 2-dimensional M-mode echocardiography.