Living in high altitude is challenging for the cardiovascular system, and some of highlanders develop a chronic mountain sickness (CMS). Only few data are available above the altitude of 4380m. La Rinconada is the highest mining city in the world at an altitude of 5100m.

To describe heart remodeling and pulmonary hemodynamic and study the relationship with CMS.

Rest and exercise echocardiography were performed in Lima (sea level, n=18), Puno (3810m, n=23) and La Rinconada (n=55).

Age and BMI were higher in La Rinconada (30±2; 32±3; 43±2 years and 24±1; 25.4±0.8 and 25.9±0.4kg.m-2 in Lima, Puno and La Rinconada respectively). Mean arterial pressure were normal and comparable regardless of altitude. As expected, hematocrit significantly (P<0.01) increased with altitude (44±1, 55±2 and 72±1% in the three groups). In highlanders at 5100, we observed a significant LV remodeling with a thicker LV, an eccentric remodeling and more frequent diastolic dysfunction, without difference regardless CMS status. Thought EF was normal in all people, global longitudinal strain was significantly decreased only in La Rinconada (19.3±0.4, 20±0.4 and 17.6±0.3%; P<0.01). Right ventricle area atria dimensions and mean pulmonary artery pressure increased significantly with altitude, mainly in the moderate-severe group. Free wall RV strain was significantly lower in La Rinconada (28.4±0.8, 25.3±0.9 and 21.3±0.4%; P<0.01). Total pulmonary vascular resistance were signficantly higher at rest and during exercise in La Rinconada, regardless the CMS status, but all the differences diasapeared when corrected at the same hematocrit level (45%) (Fig. 1).

These are the first data of a population living permanently above 5100m. Eccentric LV remodeling, larger right cavities, lowering myocardial strain in both ventricle are the main findings. The higher rest and exercise TVR in altitude are only related to the hematocrit level.