Impact of high altitude on echocardiographically determined cardiac morphology and function in patients with coronary artery disease and healthy controls

To evaluate the impact of high altitude on cardiac morphology and function in patients with coronary artery disease (CAD) and healthy controls. Eight patients with a history of acute myocardial infarction [53 +/- 8 years, left ventricular (LV) ejection fraction 54 +/- 6%] and a low risk score were compared with seven healthy controls (41 +/- 16 years) during the Dutch Heart Expedition 2007 at the Aconcagua (6960 m) in Argentina. An exercise test and echocardiography were performed at sea level and at base camp (4200 m). In the apical four-chamber view, right ventricular (RV) diameter, tricuspid annular plane systolic excursion (TAPSE), early transmitral inflow peak velocity (E), atrial transmitral inflow peak velocity (A), and peak tissue velocity during early diastole (E') were obtained. Changes in global LV function and wall motion score index (WMSI) were used as markers of ischaemia. There were no significant differences in individual global LV function and WMSI at high altitude compared with sea level in both groups. A significant increase in RV diameter was observed in the patient group at 4200 m compared with sea level and a trend towards the same result in the control group. A decrease in TAPSE was observed. Measurements of the E' showed a significant decrease in the LV septum and lateral wall at high altitude compared with sea level in both groups. Symptoms and echocardiographic signs of myocardial ischaemia were absent in low-risk patients with a history of CAD during and after exercise up to an altitude of 4200 m. Patients and healthy controls showed comparable changes at high altitude compared with sea level with an increase in RV diameter, a decrease in TAPSE, and decreased E' as early signs of pulmonary hypertension and LV diastolic dysfunction. As these alterations are most likely physiological adaptation to high altitude, the results seem to affirm current guidelines. The safety of expanding previous recommendations to patients with low-risk CAD to an altitude ascent of 4200 m requires confirmation in a larger study with appropriately defined clinical endpoints.