A previously healthy 40-year-old African American G2 P1 female with a 23-week twin gestation complicated by an incompetent cervix requiring a cervical cerclage presented to the emergency department with intermittent palpitations and shortness of breath for the past two months. The patient arrived via EMS complaining of persistent shortness of breath and palpitations for the past six hours. She was noted by EMS to have a tachydysrhythmia, atrial fibrillation with rapid ventricular response (RVR), and received two doses of diltiazem en route: 20 mg and then another 25 mg without rate control.
Upon arrival, the patient's shortness of breath had resolved but she continued to have palpitations. The patient denied dehydration, alcohol or caffeine use, lack of sleep, recent illness, or any other precipitating factors. Her past medical history was significant only for a previous preterm delivery at 20 weeks due to an incompetent cervix. She denied any cardiomyopathies, prior arrhythmias, or other structural heart diseases.
On physical exam, the patient was afebrile, normotensive, with a heart rate in the 130s-140s, and a respiratory rate of 25-42. Abnormal physical exam findings included bilateral crackles in the lung bases and an irregularly irregular heartbeat. Fetal heart tones were observed in both fetuses.
Initial work-up included an EKG, CBC, CMP, UA with microscopy, chest X-ray, cardiac enzymes, D-Dimer, BNP, and thyroid studies. On EKG, rate was 142 and rhythm was atrial fibrillation with rapid ventricular response. The chest radiograph revealed cardiac hypertrophy and right greater than left perihilar opacities suggestive of pulmonary edema. Laboratory examination revealed mild leukocytosis and mild elevation of D-Dimer, with the remainder of the results within normal limits.
The patient was placed on a diltiazem drip, which was titrated to 15 mg/hr without successful rate control. Her heart rate remained in the 130s and the rhythm continued to be atrial fibrillation with RVR. Digoxin was then added as a second agent, and discussions about the potential risks of cardioversion in pregnancy ensued. Fortunately, the patient converted to sinus rhythm before cardioversion became necessary. The digoxin was discontinued; the diltiazem was also discontinued after the patient subsequently developed hypotension.
The patient was admitted to hospital and was followed closely in an intermediate care unit by cardiology and OB/GYN. An ECHO was completed during her hospital admission that showed moderate left ventricular hypertrophy (LVH), and on further laboratory examination she appeared to likely have gestational diabetes. Due to her LVH, flecainide was not recommended, and due to her pregnancy it was decided that aspirin would be used for anticoagulation. The patient was discharged with follow-up with cardiology, high-risk obstetrics, and maternal fetal monitoring for the remainder of her pregnancy.