CORONARY HEART DISEASE

PREDICTIVE VALUE CHANGES IN R-WAVE AMPLITUDE AFTER EXERCISE

Abstract

Objective: To assess the value of coronary events reflected by changes
in R-wave amplitude after exercise.Setting: Nishtar Hospital, Multan. Duration. One year. Study Design: comparative
study.Material and Methods: Sample size 146 patients.Sampling Technique: Convenient probability sampling done.
Results: 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. Conclusion: 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.