Risk of cardiovascular events during mountain activities.

Sudden cardiac death (SCD) is the major cause of fatalities in males over 34 years of age during hiking or downhill skiing in the mountains. The main goal of the present study was the identification of risk factors and triggers associated with SCDs during these mountain activities. Besides recording individual circumstances associated with SCD, a case-control study was performed comparing the risk factor profiles of 247 males over the age of 34 who suffered SCD during mountain hiking or downhill skiing with those of 741 matched controls. The SCD risk was greatest on the first day at altitude but altitude per se and the duration of activity did not appear to markedly modify this risk. In contrast, the longer the time from the last food and fluid intake during hiking, the higher was the SCD risk. Early cardio-pulmonary resuscitation was started in 33% of skiers and in 14 % of hikers after occurrence of unconsciousness. Hikers who died suddenly during mountain hiking were much more likely to have had a prior myocardial infarction (MI) (17% vs. 0.9%), known coronary artery disease (CAD) without prior MI (17% vs. 4%), diabetes (6% vs. 1%), hypercholesterolemia (54 % vs. 20%), and were also less engaged in regular mountaineering activities (31% vs. 58%) compared with hikers from the control group (all P < 0.001). Skiers who suffered SCD had much more frequently a prior MI (41% vs. 1.5%), hypertension (50% vs. 17%), known CAD without prior MI (9% vs. 3%), and were less engaged in regular strenuous exercise (4% vs. 15%) when compared to controls (all P < 0.05). These findings enable identification of skiers and hikers at increased SCD-risk and recommendation of preventive measures, e.g. pharmacological interventions and adaptation to specific mountain activities. They also underline the need for intensified cardio-pulmonary resuscitation training for all mountaineers.