Dyspnea in a pregnant 20-year-old woman with electrocardiographic right ventricular enlargement.

A 20-year-old woman, who was 2 months pregnant, came to the cardiology clinic complaining of exertional dyspnea of 6-months duration. Her chest was clear to auscultation, and the neck veins were modestly elevated. The second heart sound was single and loud. There was no cyanosis or clubbing. A midline sternal scar was noted and was described by the patient as the incision for a heart operation when she was 2 months old. An electrocardiogram showed sinus arrhythmia, marked right axis deviation (+135 ̊ as judged by equally positive QRS complexes in leads II and aVR), and right ventricular enlargement with a qR complex in lead V1 (Figure). Electrocardiograms with this extreme degree of right ventricular enlargement are rare in adults but may be seen in severe pulmonic stenosis with an intact ventricular septum, tetralogy of Fallot, the Eisenmenger reaction, primary pulmonary hypertension, and simple transposition of the great arteries with surgical redirection of the pulmonary and systemic venous blood at the atrial level via a baffle, i.e., the Albert-Senning-Mustard operation (1–3). The first two diagnoses are ruled out by the absence of a precordial murmur. The second and third are excluded by the lack of cyanosis. The heart operation at 2 months of age indicates a congenital malformation, thus excluding primary pulmonary hypertension. The absence of right bundle branch block strongly suggests that the operation did not include a right ventriculotomy. Thus, the only tenable diagnosis is transposition surgically corrected at the atrial level. Electrocardiographic Report