Gender and the relationship between resting heart rate and left ventricular geometry

Heightened mortality is common to both an elevated resting heart rate and left ventricular hypertrophy (LVH). We examined the relationship between resting heart rate and left ventricular geometry.

We analysed resting heart rate and echocardiographic data on 1,685 individuals aged 25-93 years, 756 males and 929 females, without heart failure. The study population, 719 normotensives and 966 untreated hypertensives, was derived from the Egyptian National Hypertension Project (1991-94); a cross-sectional study of the prevalence of hypertension and cardiovascular risk factors in Egyptians. The mean of the last two of three heart rate readings was used to represent the resting heart rate.

Left ventricular mass index (LVMI) was weakly inversely related to heart rate in total males (r= -0.14, P< 0.0005) and total females (r= -0.1, P= 0.007) after controlling for age and blood pressure. The relative wall thickness (RWT) of the left ventricle was positively associated with heart rate in females. Resting heart rate increased linearly from 83.8 to 89 b.p.m. (P= 0.03) from the lowest (< or = 0.33) to highest (> or = 0.47) RWT quintiles in hypertensive females after adjusting for age and blood pressure. In both those with and without LVH (defined as LVMI > 125 g/m2), hypertensive females with RWT > 0.45 compared to those with RWT < or = 0.45 had consistently higher resting heart rate (93.8 b.p.m. versus 84.2 b.p.m., P = 0.047 and 88.9 b.p.m. versus 85 b.p.m., P = 0.005, respectively) after adjusting for age and blood pressure. No such relationship was found in males.

Among hypertensive females, an elevated resting heart rate is associated with abnormal left ventricular geometry, namely, concentric left ventricular remodelling and hypertrophy.