Increase of R-wave in pre-discharge ergometric test after myocardial infarction indicates advanced left ventricular injury, latent serious arrhythmias and worse prognosis.

Changes in R-wave amplitude during exercise tests performed soon after myocardial infarction (15-31 days, mean 22) were analyzed in 78 men in relation to left ventricular injury (determined by 2-D echocardiography), ventricular arrhythmias (24-h Holter monitoring) and survival after myocardial infarction. It has been found that in patients with mild left ventricular injury (n = 51, Heger index < or = 3) the sum of the R-wave amplitude in 15 precordial leads recorded immediately after exercise decreased by 3.7 +/- 10% in comparison with resting values. In the patients with major left ventricular injury (n = 26, Heger Index > 3) the sum of R-wave amplitude after exercise increased by 12.9 +/- 17.5% (P < 0.001). Positive linear correlation (r = 0.35, P < 0.01) was observed between the level of left ventricular wall motion disturbances and R-wave amplitude changes. In patients with normal or slightly disturbed cardiac rhythm (n = 42, Lown scale 0-2) the sum of the R-wave amplitude after exercise decreased by 5 +/- 18% as compared to resting values, whereas in the patients with complex arrhythmias (n = 23, Lown scale 3-5) the sum of R-wave amplitude increased amounting to 9.9 +/- 17% (P < 0.001). Out of 17 patients who died during 5-year follow up, 16 displayed an increase or no change of the sum of R-wave amplitude. The same kind of relations between R-wave amplitude changes and left ventricular injury or cardiac arrhythmias were noted in patients with anterior and inferior myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)