Dilated hearts at high altitude: words from on high.

From the time of the turn of the twentieth century, dilated hearts and presumed cardiac fatigue in expeditionary climbers and scientists have been the subject of much commentary in the medical and mountaineering literature. Although largely attributed by most, but not all, to left heart strain, the description of dilated hearts in these accounts is clearly that of right heart dilation as a consequence of high and sustained hypoxic pulmonary vasoconstriction with hypertensive remodeling. This essay will feature quotations from the writings of high altitude pioneers about dilated, strained, or enlarged hearts. It will give some brief physiology of the right side of the heart as background, but will focus on the words of mountaineers and mountaineering physicians as color commentary.