Right Ventricular Hypertrophy in People Born and Living at High Altitudes

Radiological studies made two decades ago by Peruvian investigators showed enlargement of the cardiac silhouette of people living at high altitudes (Rotta, 1955a;Perez Aranibar, 1948).The electro- cardiographic investigations of Rotta and Lopez (1959) and Peiialoza et al. (1960, 1961) demon- strated a right ventricular preponderance in these people.Recently a mild degree of pulmonary arterial hypertension has been found in natives from high altitudes (Sime et al., 1963; Penialoza et al., 1963) and anatomical changes in the terminal branches of the pulmonary arterial tree which may explain the origin of the pulmonary hypertension have also been reported (Arias-Stella and Saldafia, 1963).Studying two series of necropsies of children, one at sea-level and the other at high altitude, we were able to demonstrate the anatomical existence of right ventricular hypertrophy in children born and living at 12,375 to 14,300 feet above sea-level (Arias-Stella and Recavarren, 1962; Recavarren and Arias-Stella, 1962).Rotta (1955b) found evidence of right ventricular hypertrophy in 4 out of 5 hearts of adults living in Morococha (14,900 feet above sea-level) and in 1957, Campos and Iglesias found evidence of right ventricular hypertrophy in 31-4 per cent of 49 adults who died from accidents in La Oroya, at 12,375 feet above sea-level.This last finding may well raise the question: why do only one-third of the natives from high altitudes show this alteration?The anatomical characteristics of the hearts of two series of necropsies, one performed at sea- level and the other at high altitude, are investigated in detail in the present study, and it is shown that 93 per cent of the adult natives living from 12,375 to 14,300 feet above sea-level present a certain degree of right ventricular hypertrophy. MATERIAL AND METHODSHearts from 112 people whose ages ranged from 11 to 80 years were investigated.Among these, 57 were from sea-level (control group, altitude not over 584 feet) and 55 from high altitude (42 at Cerro de Pasco at 14,300 feet, and 13 at La Oroya at 12,375 feet).The distribution of control and problem cases in each decade of age was as follows.From 11 to 20 years there were 7 cases from high altitude and 22 from sea- level; from 21-30 years there were 16 cases from high altitude and 13 from sea-level; from 31-40 years there were 16 cases from high altitude and 12 from sea-level; from 41-50 years there were 9 cases from high altitude and 6 from sea-level; from 51-60 years there were 2 cases from high altitude and 1 from sea-level; from 61-70 years there were 4 cases from high altitude and 1 from sea-level; and from 71-80 years there was 1 case * Supported by United States Public Health Service Grant H-7000-03 and Public Health Grant Rg-8576.