A 29-year-old gravida 3, para 2 woman presented to the cardiology clinic at 28 weeks+2 days of gestation, with a two-month history of shortness of breath, increasing in severity in the preceding two weeks, and with associated orthopnea and intermittent palpitations. She had two previous uneventful vaginal deliveries with gestational hypertension and gestational diabetes complicating both those pregnancies. Her past surgical history was uneventful apart from a laparoscopic appendectomy and cholecystectomy which were uncomplicated. The current pregnancy was also uneventful with a well-grown fetus. She was on low-dose aspirin since the 12th week of gestation, in view of previous gestational hypertension. All her investigations were normal in this pregnancy including full blood count, screening for gestational diabetes, Hepatitis B, and HIV serology, and anatomy scan done at 22 weeks of gestation. A transesophageal echocardiogram done at another hospital at 26 weeks of gestation showed a left atrial myxoma 3.2 x 2.7 cm attached to the interatrial septum with intermittent brief mitral inflow obstruction and ejection fraction of 58%.
When she presented at our hospital, she did not require medications from a cardiac point of view. At 29 weeks of gestation, she was given dexamethasone 6 mg/12-hourly for two days to enhance fetal lung maturity. We repeated the echocardiogram after admission which showed normal biventricular dimensions, cavity size, resting wall motion, and systolic function. The left ventricular ejection fraction was 67%. A large highly mobile mass measuring 28 x 27 mm was noted in the left atrium with a thin stalk attaching to the interatrial septum. The heterogeneous density and overall appearance were consistent with a left atrial myxoma. This mass was noted to intermittently obstruct the left ventricular inflow as it prolapsed across the mitral valve annulus and into the left ventricle during the diastolic phase of the cardiac cycle. The effective mitral valve orifice in diastole was reduced to 1.9 cm2 and generated a mean diastolic gradient of 4 mmHg at a heart rate of 75/min. This was consistent with moderate left ventricular inflow obstruction. There was no evidence of pulmonary hypertension.
Further plan of management was discussed in a multidisciplinary meeting involving a cardiothoracic surgeon, a cardiologist, an obstetrician, a neonatologist, and a cardiac anesthesiologist. After discussing all possible options with the patient and her spouse, it was decided to proceed with surgical excision of the myxoma.
The woman underwent left atrial mass excision under general anesthesia at 30 weeks of gestation. A median sternotomy incision was performed. Cross clamp time was 64 minutes. Cardiotocogram (CTG) was taken before and after the surgical procedure to monitor fetal well-being. Surgery was uneventful and she was shifted to the postoperative cardiac care unit (CCU) for monitoring. CTG post-procedure showed fetal tachycardia and reduced beat-to-beat (BTB) variability which settled by 12 hours postoperatively. This was attributed to the prematurity of the baby and continuous intravenous infusion of morphine given to the mother for pain relief. On the eighth-day post excision, a bedside transthoracic echocardiogram revealed an intact interatrial septum with no myxoma remnant. She was discharged on the ninth day in stable condition with advice to keep the pregnancy monitored at her regional hospital. She remained asymptomatic and underwent a cesarean section at 41 weeks of gestation for failed induction of labor. The outcome was a female baby with a birth weight of 3060 g and Apgar scores of 9 and 10 at 1 and 5 minutes. Both mother and baby were discharged on the third day in stable condition.