A 60-year-old man with COPD is chronically hypoxemic and hypercapnic.A standard electrocardiogram (ECG) reveals a strongly negative QRS complex in lead I and a more positive than negative QRS complex in aV_F.What explains this finding?

Question

Quizplus · Accepted Answer

These QRS recordings reveal a right axis deviation. In other words, the mean direction of current flow in the ventricles is toward the +90-degree to +180-degree quadrant. A strongly negative QRS in lead I indicates that the heart's current is flowing almost 180 degrees away from lead I's positive electrode. This finding is consistent with the patient's history.

A 60-Year-Old Man with COPD Is Chronically Hypoxemic and Hypercapnic