If done during an angina attack, ECG is likely to show reversible ischemic changes: T wave discordant to the QRS vector ST-segment depression (typically) ST-segment elevation Decreased R-wave height Intraventricular or bundle branch conduction disturbances Arrhythmia (usually ventricular extrasystoles) Between angina attacks, the ECG (and usually LV function) at rest is normal in about 30% of patients with a typical history of angina pectoris, even those with extensive 3-vessel disease.