How does left ventricular systolic and diastolic function differ between patients with systemic hypertension, hypertrophic cardiomyopathy, and normal subjects?
In hypertrophied ventricles from hypertension or hypertrophic cardiomyopathy, diastolic function is consistently impaired, whereas myocardial contractility is depressed in HCM but maintained in hypertension.
To investigate left ventricular (LV) systolic and diastolic function in cardiac hypertrophy, we analysed LV pressure (catheter tip-manometer) and simultaneously performed cineangiography in 24 patients with systemic hypertension (HT), 25 patients with hypertrophic cardiomyopathy (HCM) and 25 normal subjects. We digitized LV cineangiograms frame by frame and computed volume and its derivatives, wall thickness and circumferential wall stress. LV systolic pump function was normal or supernormal in HT and HCM. However, myocardial contractility assessed by end-systolic wall stress-volume relation was depressed in HCM whereas it is normally maintained in HT. LV diastolic function was also impaired in HCM and even in HT despite normal systolic function. The LV hypertrophy group showed significantly prolonged time constant of isovolumic relaxation, increased time from end-systole to the peak filling rate, and upward shift of the diastolic pressure-volume relationship. The characteristic findings of LV diastolic function in LV hypertrophy, therefore, can be summarized as impaired isovolumic relaxation, delayed early diastolic filling and decreased diastolic distensibility. The mechanisms of abnormal systolic and diastolic function may include myocardial ischemia and/or calcium overload in hypertrophied myocardium, but further study will be needed to clarify these problems.
Yamakado et al. (Mon,) studied this question.