Frequency and Outcome of Arrhythmias Complicating Admission During Pregnancy: Experience From a High-volume and Ethnically-diverse Obstetric Service

Background: Arrhythmias are reported during pregnancy, although hospitalization for these infrequent events is not fully characterized. The frequency and outcome of arrhythmias during pregnancy are unknown. Methods: Between 1992 and 2000, there were 136,422 pregnancy-related admissions to Parkland Memorial Hospital (Dallas, TX, USA). Using the discharge diagnosis data bank and the International Classification of Disease, 9th revision, Clinical Modification (ICD-9-CM) coding system, we identified 226 admissions (218 patients) where cardiac arrhythmias and intrauterine pregnancy were both reported. Results: The most common rhythm disturbances during pregnancy were sinus tachycardia (ST), sinus bradycardia (SB), or sinus arrhythmia (SA) (104 episodes/100,000 pregnancies). This was followed by paroxysmal supraventricular tachycardia (PSVT) and premature beats, with a frequency of 24/100,000 and 33/100,000, respectively. Paroxysmal supraventricular tachycardia occurred most frequently in the third trimester or peripartum. All episodes terminated spontaneously or were safely terminated with medical therapy. Advanced heart block or lethal arrhythmias were exceedingly rare during pregnancy. Conclusion: Most frequently reported cardiac arrhythmias in pregnancy are benign and do not require intervention. Supraventricular tachycardia (SVT), being one of the most common complicated cardiac arrhythmias during pregnancy, can be treated effectively and safely with standard medical therapy. Ventricular arrhythmias or high-degree atrioventricular block (AVB) during pregnancy are extremely rare. Cardiac arrest is also rare, and is often caused by a different etiology from the conventional ones for sudden cardiac death.