Coronary heart disease; Predictive value changes in R-wave amplitude after exercise

ABSTRACT

To assess the value of coronary events reflected by changes in R-wave amplitude after exercise. Nishtar Hospital, Multan. One year. Comparative study. Sample size 146 patients. Convenient probability sampling done. All patients were followed up for 6 months, during which time myocardial infarction and death of cardiovascular origin were considered endpoints. The incidence of events in patients in whom R-wave amplitude decreased [normal response] and in those in whom R-wave amplitude did not change or increase [abnormal response] was compared. The incidence of coronary events in patients with a normal response was 23% and in those with an abnormal response, 45.8% [p<0.01]. Correlating the results with several non invasive and angiographic variables, an abnormal R-wave response showed a significantly higher rate of events in the subsets of patients with prior myocardial infarction, absence of cardiomegaly, maximal functional capacity lower than 4 METs, maximal heart rate higher than 140 beats/min and abnormal left ventricular function. The changes in R-wave amplitude after exercise is a variable that should be taken into account when assessing the risk of future events in patients with coronary heart disease