Early repolarization (ER) represents a normál ECG variant of persistent ST segment elevation. ER has ele-vated, upward and concave ST segments, notched R and tall, peaked T. It can be misinterpreted as changes consistent with acute coronary ischemia and lead to the potentially harmful invasive procedures. In group of 576 healthy subjects (356 men, 220 women) aged 15-55 years, ER was ascertained in 40 % probands, more in men (m: w = 6:1). ER occurred frequently in younger, slim and fit subjects and people engaged in sports, in physically active blood donors in higher age categories. ECG signs of ER resolve with maximal exercise testing. In doubt, a use of echocardiography to refuse or concern regional wall abnormalities is recommended. Two ECG of patients from cardiologic ambulance are presented. 48 years old marathon run-ner with asymptomatic right bundle branch block and ST segment elevation has normál outcome of coro-narography. 51 years old man with acute coronary ischemia and critical right coronary artery stenosis was subjected to acute percutaneous coronary intervention with stenting, and ECG changes of ST elevation immediately resolved.

        Key words: ST segment elevation, early repolarization, occurrence in healthy persons, acute coronary ische-