[Pseudoischemic ST-segment due to atrial repolarization during exercise test. Review of the literature, diagnostic criteria and personal experience].

Atrial repolarization wave has been known since many years: it is opposite in direction to P wave, may have a magnitude of 100 to 200 microV and may extent into the ST segment (usually it is hidden in the QRS complex). It was hypothesized that this wave could cause ST-segment depression mimicking myocardial ischemia. The false positive response is characterized by marked downsloping of the PR segment at peak exercise, longer exercise time (> 6 min), peak exercise heart rate > 125 bpm, absence of chest pain and ST-segment normalization in the first minute of recovery. In our experience a role of atrial repolarization in ST-segment depression was found in 5.5% of 144 consecutive and non-selected individuals evaluated with exercise testing.