Moderate altitude and myocardial ischemia and infarction

This study compared visitors to a moderate altitude (1,829 m to 3,10D m) hospitalized with myocardial ischemia and/or infarction to hospitalized residents of that moderate altitude with similar diagnoses. The purpose was to quantify, describe and compare visitor and resident characteristics and hospital courses in order to determine whether a relationship existed between the severity of myocardial ischemia and/or infarction occurring at moderate altitude and the altitude of residence. The study group consisted of 112 patients admitted to the Intensive Care-Coronary Care Unit of a 64 bed rural hospital with either myocardial ischemia or myocardial infarction. The study design was an ex-post facto chart review for a 36 month period. Subjects were divided into two groups of either visitors or residents of the study area. These two groups were further subdivided into subjects with ischemia and subjects with infarction. Data on numerous variables was collected from the medical record. Using an independent student t-test and chi-square statistic no relationship was found between the severity of ischemia or infarction and the altitude of residence. There were no significant differences during hospitalization between visitors and residents in complications, length of hospitalization or length of supplemental oxygen usage. Based on a Spearman Rho correlation and independent student t-test, findings do suggest that altitude may affect physiologic response to ischemia or infarction. Visitors tended to have more frequent ventricular tachycardia and sinus bradycardia and higher admission blood pressures. Prior to hospitalization altitude may have affected visitors' abilities to compensate for an ischemic event. This is suggested by the findings that a larger percentage (46%) of the visitor population was diagnosed with myocardial infarction than was the resident group with only 30% diagnosed with infarction.