Risk factor profile for sudden cardiac death during mountain hiking

Mountain hiking is associated with a death rate of about 4 deaths per 100000 hikers annually. About 50% of all fatalities during mountain hiking are sudden cardiac deaths (SCDs). But there are only few data available regarding risk factors and triggers associated with SCD during mountain hiking. Thus, a case-control analysis between persons who died suddenly during mountain hiking and randomly selected controls was carried out. Risk factor profiles of 179 males over the age of 34 who suffered SCD during mountain hiking were compared to those of 537 matched controls. Hikers who died suddenly during mountain hiking were much more likely to have had a prior MI (17 % vs. 0.9 %; p < 0.001), known coronary artery disease (CAD) without prior MI (17% vs. 4%; p<0.001), diabetes (6% vs. 1%; p<0.001), hypercholesterolemia (54% vs. 20%; p<0.001), and were less engaged in regular mountain sports activities (31% vs. 58%; p<0.001) compared to hikers from the control group. Based on the reported relationship between traditional risk factors and coronary plaque morphology, acute plaque rupture with thrombus formation and subsequent lethal arrhythmias may be assumed to be a dominant mechanism precipitating SCD during hiking. In contrast, in skiers especially non-occlusive plaques may precipitate ischemia leading to an imbalance between oxygen demand and supply and subsequent lethal arrhythmias. As preventive measures recommended to hikers at risk, adaptation to regular mountain sports activities by an adequate training program and pharmacological interventions, e.g. lipid lowering drugs, aspirin, and betablockers, should be considered.