A 42-year-old man has a two-year history of exertional dyspnea. In the past six months, his condition has become significant enough to force him to leave his job as a general contractor. He presents today with dizziness while standing, but not while walking. He denies syncope or near-syncope, angina, or palpitations.

He says he has gained weight over the past month, to the extent that his clothes no longer fit. He attributes this to not working or exercising, and he believes this may be the cause of his increased exertional dyspnea.

Medical history is remarkable for pneumonia 10 years ago. Surgical history is remarkable for repair of a right femoral fracture sustained in an automobile accident at age 17.

The patient has worked in construction and as a general contractor, but had to stop two months ago secondary to dyspnea and chronic fatigue. He is unmarried, is active in his church, does not smoke or drink, and denies recreational drug use. His father died at 66 of lung cancer related to smoking. His mother and three siblings are alive and in good health. He is not allergic to any known medications, and his current medications include ibuprofen as needed for muscular aches and pains and an aspirin a day “because my dad’s doctor recommended it.”

The review of systems is remarkable for fatigue despite the fact that the patient has been getting plenty of sleep. His girlfriend says he has been snoring loudly for the past two weeks and has never snored in the past. The man also states that he has had vague abdominal discomfort, without change in his bowel or bladder habits, and has noticed swelling in his lower extremities. He is alarmed to find out he has gained 24 lb in the past month.

The physical exam reveals an anxious, obese, white man with a weight of 298 lb. Vital signs include a blood pressure of 114/80 mm Hg; pulse, 94 beats/min; respiratory rate, 20 breaths/min; and O2 saturation, 90% on room air. He is afebrile.

Pertinent physical findings include jugular venous distention to the angle of the jaw and lungs that are clear to auscultation with a few late expiratory wheezes. The cardiac exam reveals distant heart sounds with a grade III/VI holosystolic low-frequency murmur best heard at the left lower sternal border. The abdominal exam is remarkable for mild hepatomegaly, which is tender to deep palpation. The lower extremities demonstrate 2+ pitting edema to the level of the knees bilaterally. The neurologic exam is intact.

Laboratory blood work, an echocardiogram, and an ECG are ordered. The ECG is performed first and reveals the following: a ventricular rate of 94 beats/min; PR interval, 186 ms; QRS duration, 98 ms; QT/QTc interval, 384/480 ms; P axis, 62°; R axis, 90°; and T axis, 48°. What is your interpretation of this ECG, and how does it correlate with the history and physical exam?

ANSWER

The ECG reveals sinus rhythm with a marked sinus arrhythmia, biatrial enlargement, incomplete right bundle branch block, right ventricular hypertrophy, ST and T wave abnormalities in the anterolateral precordial leads, and a prolonged QT interval.

There is a P for every QRS and a QRS for every P, and each P wave is similar in its respective lead (sinus rhythm); however, the rate is irregular, hence the diagnosis of marked sinus arrhythmia. Biatrial enlargement is illustrated by the presence of notched P waves in leads I and V₁ with peaked P waves in leads II, III, and aVF (right atrial enlargement) and a P wave ≥ 110 ms in lead I with a terminally negative P wave ≥ 1 mm² in V₁ (left atrial enlargement).

An incomplete right bundle branch block is illustrated by the presence of an RSR’ in lead V₁ with a small R and a QRS duration which is borderline normal (< 100 ms). Right ventricular hypertrophy is demonstrated by the presence of a tall R wave in V₁ (in this case, R’) that is ≥ S wave in V₁, an inverted T wave in V₁, borderline right-axis deviation (R axis, 90°), and right atrial enlargement.

ST and T wave changes in the lateral leads are suggestive of anterolateral ischemia; however, in this case they are indicative of repolarization changes from right ventricular enlargement and an incomplete right bundle branch block. Finally, QT prolongation is suggested by the presence of a QT interval > 400 ms in a man when corrected for rate.

The patient’s history, physical examination, and ECG are highly suspicious for right-sided heart failure with the presence of jugular venous distention, a murmur of tricuspid insufficiency, hepatic congestion, and peripheral edema, as well as ECG documentation of right atrial and ventricular enlargement (cor pulmonale). An echocardiogram subsequently confirmed the diagnosis and also revealed pulmonary hypertension, with pulmonary artery pressures of 70 mm Hg.