Marked PR interval prolongation simulating ST-segment elevation during exercise testing. A case report

ST-segment elevation during exercise testing is usually indicative of severe proximal coronary artery disease. In this report, the authors describe a patient who underwent exercise stress testing and developed apparent ST elevation in the inferolateral leads. However, noninvasive imaging studies revealed no evidence of myocardial ischemia or other recognized causes of this exercise electrocardiographic (ECG) finding. Analysis of the ECG tracings showed that ST elevation was produced by marked prolongation of the PR interval, super-imposing the P wave on the J-junction of the preceding QRS-ST-segment complex. The authors suggest that marked PR prolongation during exercise may mimic ST elevation, and this possibility should be considered in patients with this exercise ECG finding in whom cardiac evaluation is negative.