[Mean high-amplification electrocardiogram during a submaximal exercise test following acute myocardial infarction].

The mean high-amplification ECG (MECG) used to detect delayed potentials (DPs) has so far been used only at rest and after exertion. In this article, the results are reported of recording the MECG at rest and during exercise (ER) obtained in 19 patients, the ER having been carried out at the subacute stage of myocardial infarction. Despite a significant increase in the background noise during exercise from 0.9 microV to 2.2 microV, it was possible to analyse the MECG recorded during exercise to detect DPs in all cases. In this small group of patients, no significant changes occurred with regard to the appearance or delayed potentials during exercise, although there was a reduction in the duration of HFQRS and an increase in the amplitude of RMS40 during exercise which was, however, much less marked in patients presenting DP.