Cardiopulmonary exercise response at high altitude in patients with congenital heart disease: a systematic review and meta-analysis.

Background: An increasing number of patients with congenital heart disease (CHD) engage in physical activities and may exercise at high altitudes (HA). The physiological adaptations required at HA and their implications on individuals with CHD, especially during exercise, remain underexplored. This systematic review aims to investigate cardiopulmonary exercise responses to short-term HA exposure in individuals with CHD.

Methods: A literature search was performed across PubMed, Cochrane Library, Scopus, Embase, and SPORTDiscus. The search focused on studies comparing patients with CHD to healthy controls, specifically assessing cardiorespiratory responses during cardiopulmonary exercise testing at HA (≥2,500 m) and low altitude (LA). A meta-analysis of the differences in the main cardiorespiratory adaptations during exercise from LA to HA was performed, comparing patients with CHD and controls.

Results: Of the initial 4,500 articles, four studies met the inclusion criteria, encompassing 150 participants (74 with CHD and 76 controls). Almost all the patients with CHD had lower cardiorespiratory fitness and efficiency both at LA and HA compared to the controls. Nevertheless, the patients with CHD showed a smaller decrease in peak workload [10.61 W (95% CI: 2.33-18.88)] and peak saturation [1.22% (95% CI: 0.14-2.30)] between LA and HA compared to the controls. No participants presented exercise-induced symptoms.

Conclusion: Short-term exposure to HA appears to be relatively well-tolerated by individuals with low-risk CHD, without a significantly different impact on cardiorespiratory response compared to healthy controls. Further research should confirm these outcomes and explore the long-term effects of higher altitude exposure as comprehensive recommendations for these patients are lacking.