A 42-year-old man with no prior cardiac history develops sudden-onset substernal chest pressure while playing touch football. There is no shortness of breath, nausea, vomiting, or diaphoresis; he says he “just doesn’t feel quite right.”

After he rests for approximately 15 minutes, the pressure subsides. He resumes play, only to have the pressure promptly return. At the insistence of his friends, he presents to the emergency department for evaluation.

The patient’s medical history is remarkable for cholecystitis and hemorrhoids. His family history is remarkable for a father who experienced an MI at age 60, a mother with hypertension and hyperlipidemia, and a grandfather who died at age 66 of complications of a stroke.

The patient takes no medications and has no drug allergies. He drinks one or two six-packs of beer on the weekends and smokes approximately two packs of cigarettes per week. He works as a construction manager and eats exclusively at fast food restaurants. A comprehensive review of systems is remarkable only for bleeding hemorrhoids.

The physical exam reveals an anxious, obese male with a weight of 264 lb; height, 70 in; blood pressure, 166/98 mm Hg; pulse, 80 beats/min; and respiratory rate, 18 breaths/min. Pertinent physical findings include clear lungs bilaterally, jugular venous distention to 6 cm, and regular rate and rhythm, with a grade II/VI systolic murmur best heard at the left lower sternal border. Peripheral pulses are equal bilaterally, and there is no peripheral edema.

A stat ECG is obtained, which reveals the following: a ventricular rate of 80 beats/min; PR interval, 160 ms; QRS duration, 74 ms; QT/QTc interval, 414/477 ms; P axis, 73°; R axis, 110°; and T axis, 79°. What is your interpretation of this ECG?

ANSWER

The ECG shows sinus rhythm with frequent premature ventricular contractions (PVCs), fusion complexes, and an anterolateral MI. PVCs are premature (electrical impulse in the ventricle preceding the next sinus node depolarization), ectopic (not originating from the sinus node), and wide complex (not following normal His-Purkinje system, and hence wider than a normal sinus complex); they result in a compensatory pause due to a refractory sinus node at a time when the next sinus depolarization would be expected.

Fusion complexes develop when a normal sinus depolarization occurs simultaneously with an ectopic ventricular beat (PVC), resulting in a merge, or fusion, of the two depolarizations. As a result, the intrinsic deflection is similar to but wider than a normal sinus beat. In this ECG, the first QRS complex represents a normal sinus beat, the second QRS complex represents a PVC, and the third represents a fusion beat.

Q waves, QS waves, or QRS complexes in leads V₂ to V₃ (or V₄) with evolving ST-T wave changes suggest an anterior MI. An anterolateral infarction includes Q waves in lead V₄ to V₆, as is the case here. Cardiac catheterization confirmed proximal occlusion of the left anterior descending artery.