[High altitude and cardiac disease].
Hypoxia at high altitude is associated with an increase in myocardial work. Cardiovascular effects of high altitude may affect patients suffering from cardiac diseases and raise questions concerning the tolerability of exposure to altitude. In general, altitudes up to 2500 to 3000 meters do not pose a hazard for a patient with stable coronary artery disease and good exercise tolerance. Likewise, a patient suffering from heart failure does not necessarily refrain from these altitude exposures unless exercise capacity and left ventricular ejection fraction are severely impaired. However, cardiac patients have to be informed that symptoms may occur already at lesser efforts at high altitude compared to low altitude. Therefore, patients should be advised to adapt physical activities, particularly during the first 3-4 days of acclimatization. In commercial airplanes pressure conditions are comparable to altitudes of 1500 to 2400 meters. Most cardiac patients tolerante the associated physical stress without difficulty. Contraindications for air travel include unstable cardiac conditions, recent cardiac interventions (2-3 weeks), an uncomplicated myocardial infarction within the last 2 weeks, or a complicated myocardial infarction within the last 6 weeks, respectively. The risk of exposure to altitudes above 3500 meters is not well known for cardiac patients because of a lack of corresponding data. Thus, patients who would like to mountaineer at very high altitudes have to be advised individually based on their physical condition and on the severity of their cardiac illness.