ECG of the Month: Variable QRS Morphologies in Heart Failure

This is a 50-year-old man with a past medical history of chronic systolic heart failure on chronic inotropic therapy who presented with worsening dyspnea over the past two days. A right heart catheterization performed at the time of admission demonstrated a cardiac index of 1.4 and an elevated SVR greater than 2300 Woods units. Medical history is otherwise notable for coronary artery disease, atrial fibrillation, WHO Group II pulmonary hypertension and signet ring adenocarcinoma.

Figure 1

An ECG performed upon admission demonstrates which of the following:

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