Cardiopulmonary response to exercise at high altitude in adolescents with congenital heart disease

Abstract

Objective: To extend our knowledge on tolerance of acute high-altitude exposure and hemodynamic response to exercise in adolescents with congenital heart disease (AscCHD) without meaningful clinical or functional restric-tion. Methods: A symptom limited cardiopulmonary exercise stress test and a non-invasive cardiac output measurement during steady state exercise were performed at 540 m and at 3454 m a.s.l. Symptoms of acute mountain sickness were noted. Results: We recruited 21 healthy controls and 16 AscCHD (59% male, mean age 14.7 ± 1.1 years). Three subjects (2 controls, 1 AscCHD) presented light symptoms of acute mountain sickness (dizziness and headache). During the symptom limited exercise test at lowland, control subjects showed a significantly higher power to weight index (3.5 ± 0.6 W/kg vs. 3.0 ± 0.7 W/kg, p < 0.001), heart rate (188.8 ± 10.4 1/min vs. 179.4 ± 13.1 1/min, p <0.050)andventilation(92.8±22.9l/minvs. 75.4 ± 18.6 l/min, <0.050). At altitude, power to weight index only remained significantly higher in the control group (2.8 ± 0.6 W/kg vs. 2.6 ± 0.6 W/kg, p < 0.001). Pulmonary blood flow (PBF) at lowland showed no difference between the control and the AscCHD group, neither at rest (5.4 ± 0.8 l/min vs. 5.1 ± 0.9 l/min, p = 0.308), nor during the steady state test (10.6 ± 2.4 l/min vs. 10.5 ± 2.0 l/min, p = 0.825). At high altitude, PBF increased by 110% and 112%, respectively (12.8 ± 2.32 l/min vs. 12.5 ± 3.0 l/min; intergroup difference: p = 0.986). Conclusions: High altitude exposure was well tolerated in an unselected group of AscCHD. No significant difference in the cardio-pulmonary adaptation to a control group was noted during a steady state exercise. Symptoms of minor acute mountain sickness did occur, which should however not be misinterpreted as signs of hemodynamic maladaptation.