Clinical, biochemical, electrocardiographic and noninvasive hemodynamic assessment of cardiovascular status in natives at high to extreme altitudes (3000m-5500m) of the Himalayan region.

Cardiovascular status was studied in 500 natives living at high to extreme altitudes (3000m to 5500m) of the Himalayas. No case of congenital heart disease, rheumatic heart disease, coronary artery disease, primary myocardial disease or hypertension was found. A significant rise, however, was noted in both the systolic and diastolic systemic arterial pressure with age. Serum lipid and lipoprotein profile estimation in 148 subjects showed that with increasing altitude, the HDL cholesterol increased, while the LDL cholesterol, total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL cholesterol ratio decreased. Electrocardiograms of 160 subjects (120 males and 40 females) above the age of 25 years showed right ventricular hypertrophy in 8 (5%), 6 of whom (17.6%) lived above the altitude of 4800m. Echocardiographic examination showed normal left ventricular function in all, while 27 per cent of the natives at an altitude of 4500m-5000m had evidence of pulmonary hypertension and rise of normalised right ventricular preejection period.