Human Heart Weight at High Altitude

Abstract

The weight of the right ventricle, left ventricle, and septum determined in 98 hearts of high altitude (12,300 feet) residents in Peru and in 86 hearts from sea level in the continental United States revealed that right ventricular hypertrophy is no greater at high altitude than at sea level in the stillborn-newborn infant heart. Right ventricular weight relative to total heart weight at high altitude exceeds that at sea level beginning about 30 days after birth and reaches a plateau at 56 days. Thereafter the degree of relative right ventricular hypertrophy changes only slightly through the adult years. No evidence was found of postnatal atrophy of the right ventricle either at sea level or high altitude nor of septal hypertrophy accompanying the right ventricular hypertrophy in high altitude. The degree of right ventricular hypertrophy was moderate and variable, and corresponded to the moderate, variable pulmonary hypertension previously demonstrated in high altitude residents. Since total heart weights are similar at high altitude and sea level and since high altitude subjects have a smaller body size, the heart weight/body weight ratio is probably greater in the high altitude subject.Pulmonary hypertension hood. The technique of dissection employed permits determination of the weight of the free wall of the right and left ventricles after separation from the septum and, therefore, differs from the technique employed by Arias-Stella and Recavarren-8 in which septal weight was not determined. MethodsThe method of dissection was originally described by Muller.9 Fresh hearts were fixed from 1 to 6 weeks in 10% buffered Formalin. Prior to fixation the atria were opened, blood and clots were washed out, and the heart chambers were loosely packed with cotton. Following fixation and after washing for several hours in tap water, the great vessels, atria, valves, epicardial fat, and coronary vessels were removed by sharp dissection. The right ventricle was first separated from the septum by a sharp scalpel. The plane of the cut was made parallel to the plane of the surface of the septum. The left ventricle was separated from the septum in a similar manner. The free wall of each ventricle and the septum were weighed to the nearest 0.10 g. The relative weight of the right ventricle was expressed as a percentage of the total ventricular mass (RV/T). To determine if septal hypertrophy was present when left ventricular hypertrophy was not present, the weight of the septum was expressed as a 207 by guest on June 26, 2016 http://circ.ahajournals.org/ Downloaded from

Heart Rate Variability in Rats Acclimatized to High Altitude

“…The development of right ventricular hypertrophy is a common consequence of hypoxia-increased pulmonary vascular resistance and pulmonary arterial hypertension in most mammals (including man) native to high altitude (Hultgren & Miller, 1967) or exposed to continuous chronic hypoxia (Leach et al, 1977) or to intermittent severe hypoxemia (McGuire & Bradford, 1999). However, our results showed a less marked right ventricular hypertrophy compared to those from previous reports in rats (Ostadal et al, 1989).…”

“…In addition, no difference in echocardiographic left ventricular mass was noted between N and CH rats during and after exposure. In previous studies, mammalian left ventricular mass was reported either increased (Genovese et al, 1983;Schneider et al, 1987), unaffected (Hultgren & Miller, 1967), or decreased (Scognamiglio et al, 1991) after chronic exposure to hypoxia. In our animal model, chronic exposure to mild hypoxia slowly increased posterior wall thickness and left ventricular cavity, but only in the first 3 weeks, which could not be therefore related to our HRV measurements made on day 72.…”

The haematological and cardiac patterns of adaptation of rabbits to 4,500 m simulated altitude and of readaptation to 400 m

“…Their animals suffered a striking weight loss under hypoxia. In rabbits born at altitudes comparable to ours (3,900-4,600 m) Hultgren and Miller (1967) found an 820/0 increase of the RV mass over total ventricular mass.…”

Right Ventricle and High Altitude

“…RV function in normal HA natives and in patients with Monge's disease has been recently explored by Doppler echocardiography, although RV hypertrophy was described many years ago [ 32 ].…”