When Heart Problems Crop Up

ANSWER

This ECG shows a sinus rhythm with premature atrial complexes, a normal axis, a right bundle branch block, and T-wave abnormalities consistent with lateral ischemia.

Sinus rhythm is evidenced by the P waves’ rate of ≥ 60 beats/min and ≤ 100 beats/min. The P waves that indicate premature atrial contractions have a different appearance than normal P waves, a result of the atrial activation from a site other than the sinus node. Because both the normal P wave and the premature atrial contraction conduct through the normal ventricular conduction system, the associated QRS complexes are identical.

A right bundle branch block is identified by a QRS duration > 120 ms with a terminal broad S wave in lead I and an RSR’ complex in leads V₁ and V₂. The ST segment depressions in precordial leads V₃ through V₆ propagate the diagnosis of lateral ischemia.

The patient was not found to have atrial fibrillation, and his palpitations and evidence of lateral ischemia resolved when he resumed taking his ß-blocker.