A 30-year-old pregnant woman with bradycardia

Enrique M. Velasquez, MD, Luz M. Alvarez, MD, and D. Luke Glancy, MD

From the Section of Cardiology, Department of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana (Velasquez, Glancy) and Sutter Coast Hospital, Crescent City, California (Alvarez).

Corresponding author: D. Luke Glancy, MD, Section of Cardiology, Department of Medicine, Louisiana State University Health Sciences Center, 1542 Tulane Avenue, Room 436, New Orleans, Louisiana 70112.

A 30-year-old woman (gravida 4, para 3) with full-term pregnancy presented in spontaneous labor. She had no significant medical history and was asymptomatic except for labor contractions. Her heart rate was 42 beats per minute, and her blood pressure was normal. Chest was clear to auscultation bilaterally. Her cardiac rhythm was regular with a varying first sound intensity. No murmurs were heard. Her extremities did not show significant edema.

The electrocardiogram (Figure) demonstrated complete atrioventricular block with a junctional escape rhythm at a rate of 43 beats per minute. The atrial rhythm was sinus with ventriculophasic sinus arrhythmia: the P-P intervals were shorter (0.70 to 0.75 seconds; mean 0.727) when they contained QRS complexes and longer (0.76 to 0.81 seconds; mean 0.782) when they did not. The R-R intervals were quite regular at 1.38 to 1.39 seconds. The electrocardiogram was unchanged from one recorded a year earlier. A previous evaluation had not revealed any abnormality, and the patient was presumed to have congenital complete heart block. She delivered vaginally a healthy baby and has remained asymptomatic.