Transient Ischemic Right Axis Deviation Tendency of the Frontal Plane QRS Axis in a Case of Inferior Myocardial Ischemia.

A 73-year-old man was admitted to our hospital because of chest pain at rest. Electrocardiography (ECG) showed an ST-segment depression, a negative U-wave in the precordial leads, and a right axis deviation (RAD) tendency. Coronary angiography revealed occlusion of the right coronary artery. Collateral flow from the jeopardized left anterior descending artery to the posterior descending artery (PDA) was fair. After successful revascularization, improvement in the ECG findings was noted. Since blood supply to the left posterior fascicle is dependent on the PDA, the RAD tendency could be explained by the presence of a transient ischemic left posterior hemiblock.