A 35-year-old man has endocarditis in the setting of an aortic valve replacement. One year ago, a bioprosthetic aortic valve was placed for progressive symptoms related to a congenitally bicuspid aortic valve. The patient had been offered a mechanical valve replacement, but he did not wish to take warfarin.

The patient did well until two days ago, when he developed shortness of breath, malaise, and a fever of 39°C. Though acutely ill, he continued to work through the week before coming to the emergency department (ED). Upon presentation, he abruptly develops transient left facial numbness.

Blood is drawn for cultures, a chemistry panel, and a complete blood count. A stat transesophageal echocardiogram (TEE) performed by a cardiologist in the ED reveals vegetations on the aortic valve, a perivalvular abscess, and partial dehiscence of the aortic valve annulus.

The patient’s history is also remarkable for gastroesophageal reflux disease. With the exception of his aortic valve replacement, he has had no prior surgeries. He smokes a half-pack of cigarettes per day and drinks alcohol socially on weekends. He denies recreational drug abuse and has not traveled abroad. There are no cardiac, rheumatologic, or congenital problems in the family history. His medication list at admission includes aspirin, metoprolol, and pantoprazole. He has no known drug allergies.

Physical exam findings include a blood pressure of 98/68 mm Hg; pulse, 98 beats/min; temperature, 38.8°C; respiratory rate, 18 breaths/min; and O2 saturation, 95% on room air. The patient is alert and conversant but is in a fair amount of distress, worrying that he is “going to die.”

The HEENT exam is remarkable for petechiae of the conjunctiva and buccal mucosa. The lungs have faint, moist crackles in both bases but are otherwise clear.  The cardiac exam demonstrates a regular rate and rhythm, with a grade II/VI systolic murmur and a grade II/VI early diastolic murmur best heard at the right upper sternal border. There is no S₃, S₄, or rub, and no jugular venous distention.

The sternotomy scar is well healed, and the sternum is stable. Abdominal exam is unremarkable. The extremities are not edematous, and there is no evidence of subungual or splinter hemorrhages. A neurologic exam reveals no focal defects, despite the transient left facial numbness upon presentation.

Stat laboratory results show serum electrolyte levels within the normal range. They also reveal a blood urea nitrogen level of 14 mg/dL; serum creatinine, 1.1 mg/dL; white blood cell count, 18.7 x 103/mL; and hematocrit, 39%.

An ECG performed in the ED prior to the TEE shows the following: a ventricular rate of 98 beats/min; PR interval, 174 ms; QRS duration, 82 ms; QT/QTc interval, 382/487 ms; P axis, 64°; R axis, 37°; and T axis, 20°. What is your interpretation of this ECG?

ANSWER

The correct interpretation includes normal sinus rhythm, left atrial enlargement, prolonged QT interval, and T-wave abnormality in the anterior precordial leads. A regular rhythm with a P wave for every QRS at a rate between 60 and 100 beats/min meets criteria for normal sinus rhythm. Left atrial enlargement is confirmed by a P wave in lead I ≥ 110 ms and a negative terminal P wave in lead V₁ ≥ 1 mm². A QTc interval of 487 ms is consistent with a prolonged QT interval (> 440 ms).