Background: The aim of the study was to assess gender-specific differences in left ventricular cavity size, contractility and left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy.
Methods: We studied retrospectively 129 referred patients with hypertrophic cardiomyopathy (77 males and 52 females). The echocardiographically measured left ventricular end-systolic, end-diastolic dimensions, fractional shortening and occurrence of left ventricular outflow tract gradient > or =30 mmHg were compared between sexes. Logistic regression analysis was used to calculate the predictive values of left ventricular dimensions and contractility for left ventricular outflow tract obstruction for each gender separately.
Results: Left ventricular end-diastolic and end-systolic dimensions were significantly smaller in females than males (41.7+/-5.3 vs. 45.1+/-4.9 mm, P=0.0003; 23.1+/-44 vs. 25.6+/-5.3 mm, P=0.007 respectively). On the contrary, the value of fractional shortening was comparable in both sexes (44.7+/-7.3 vs. 43.6+/-7.9%, P>0.05). The left ventricular outflow tract gradient occurred in females as frequently as in males (28.8 vs. 33.8%, P>0.05). By logistic regression analysis the predictors of left ventricular outflow tract gradient in females were left ventricular end-systolic diameter (relative risk=0.74; confidence interval (CI) 0.61 to 0.91; P=0.0038), left ventricular end-diastolic diameter (relative risk=0.82; CI 0.72 to 0.96; P=0.0061) and fractional shortening (relative risk=1.11; CI 1.01 to 1.22; P=0.036). The most potent predictor appeared to be left ventricular end-systolic dimension. In males none of these parameters identified patients with left ventricular outflow tract obstruction.
Conclusions: Females with hypertrophic cardiomyopathy featured smaller left ventricular cavity size, which predisposed to left ventricular outflow tract obstruction (the most potent predictor of left ventricular outflow tract obstruction was left ventricular end-systolic dimension). Higher left ventricular contractility also determined left ventricular outflow tract gradient occurrence in females with hypertrophic cardiomyopathy. In males despite a larger left ventricular cavity size the left ventricular outflow tract obstruction occurred with a similar frequency as in females. Left ventricular outflow tract obstruction was not predicted by left ventricular cavity size or contractility in males.