Low exercise R wave amplitude after myocardial infarction predicting subsequent non-sudden death

R wave amplitude was measured before, during and after exercise test in 68 men 6--8 weeks after acute myocardial infarction. During 6-years follow-up 21 patients died suddenly (within one hour) and 25 non-suddenly. The highest mean R wave amplitude in lead CH5 during exercise test was lower in patients with subsequent non-sudden death (1.93 mV) than in patients with sudden death (2.70 mV) (p less than 0.01). Survivors (22) had the highest mean value (2.91 mV). R wave amplitude values in lead V5 at rest in the supine position before and after exercise did not differ significantly in these patient groups.