Medical Student Université de Sherbrooke, Quebec, Canada
Case background: An 18-year-old woman, gravida 1 para 0, at 31 weeks of gestation, presented to her primary care physician with a one-week history of presyncope and palpitations. She denied chest pain, syncope, or exertional dyspnea. Her pregnancy had been otherwise uncomplicated with regular prenatal visits. Her history included hypothyroidism and an asymptomatic thickened cardiac septum, followed until age two before being discharged from cardiology. She had no known cardiac history, no family history of sudden cardiac death, and denied smoking, alcohol, or illicit drug use. Her only medication were prenatal vitamins and levothyroxine. On examination, her blood pressure was 106/78 mmHg, heart rate 80 bpm, oxygen saturation 99% on room air, and she was afebrile. Cardiac auscultation revealed a 3/6 holo-systolic ejection murmur loudest at the second intercostal space of the right sternal border, which increased with standing, decreased with squatting, and remained unchanged with handgrip. Additional findings included 1+ non-pitting bilateral lower extremity edema and mild jugular venous distention at 4 cm above the sternal angle while supine. The remainder of her physical exam was unremarkable. While awaiting further workup in-hospital, she experienced an episode of presyncope associated with hypotension (65/40 mmHg) and documented junctional bradycardia, which resolved with a fluid bolus and left lateral Trendelenburg positioning. Baseline electrocardiogram demonstrated normal sinus rhythm with left axis deviation, left atrial enlargement, ST-segment elevations in V1-V3 discordant from deep S-waves, ST-segment depression and T-wave inversions in leads I, aVL and non-specific T-wave inversions in the precordial leads (Figure 1). While undergoing continuous cardiac monitoring, there was a documented six second episode of non-sustained ventricular tachycardia. Plain film chest x-ray revealed cardiomegaly. Laboratory findings were significant for a mild elevation of high-sensitivity troponin I (31.3-33.0 ng/L; normal <= 12.0 ng/L). Transthoracic echocardiogram (Figure 2) demonstrated a severe, asymmetric septal obstructive hypertrophic cardiomyopathy with a septal thickness of 31 mm, posterior wall of 10 mm, diastolic dimension 36 mm; peak aortic valve gradient 87 mm Hg and 97 mmHg with Valsalva; 4/4 systolic anterior motion of the mitral valve with moderate mitral regurgitation; left ventricular ejection fraction was estimated to be 75%; possible patent foramen ovale. Based on these findings, the patient was diagnosed with severe obstructive hypertrophic cardiomyopathy (HCM) with high-risk for sudden cardiac death.
Management Challenges: Upon discovery of her obstructive HCM, the patient’s risk of hemodynamic instability during delivery became a primary concern. The physiological adaptations of pregnancy, including increased blood volume, elevated cardiac output, and decreased systemic vascular resistance, can exacerbate left ventricular outflow tract obstruction in patients with HCM, further increasing the risk of cardiovascular decompensation.1 The combined demands of pregnancy, acute intrapartum fluid shifts, and anesthetic considerations created a high-risk scenario for maternal decompensation during delivery. In line with AHA/ACC guidelines recommending referral to specialized centers for complex HCM cases, the patient was transferred to a quaternary care center to facilitate multidisciplinary delivery planning and access to advanced cardiac support.2 An interdisciplinary meeting was organized for risk stratification and planning with representatives from cardiology, advanced heart failure, cardiac electrophysiology, obstetrics, maternal fetal medicine, neonatology, anesthesia, and critical care. Upon transfer and thorough evaluation, the fetus was felt to be developing well, and the obstetric team determined that a cesarean section could be organized at any time. The cardiac team deemed the patient hemodynamically stable, despite the increased blood volume associated with her pregnancy. The timing of delivery was determined based on a balance between maternal hemodynamic stability and fetal development, with delivery at 32 weeks chosen to minimize maternal risk while reducing the likelihood of severe neonatal complications; earlier delivery may have improved maternal outcomes but increased neonatal risks, whereas delaying delivery heightened the potential for maternal decompensation. The patient’s stability allowed for initiation of Metoprolol to reduce heart rate, minimize obstruction, and lower arrhythmia risk. The selection of Metoprolol required careful titration to mitigate the potential for hypotension and adverse fetal effects. Due to the potential for acute cardiovascular collapse during delivery, a decision was made amongst the cardiology, critical care, anesthesia and obstetrics teams to insert a prophylactic femoral sheath to enable rapid deployment of extracorporeal membrane oxygenation (ECMO) if emergent circulatory support were required.3 Although ECMO was not ultimately necessary, this step demonstrated effective risk mitigation planning in the face of significant hemodynamic risk. To reduce the risk of perioperative cardiovascular collapse, epidural anesthesia was selected to optimize hemodynamic stability, as it provides superior control over sympathetic stimulation as compared to general anesthesia, which can induce abrupt changes in vascular tone and exacerbate left ventricular outflow tract obstruction.4 The cesarean section proceeded without complications, and the mother remained stable throughout the procedure. Postoperatively, she was closely monitored in the intensive care unit (ICU) for 24 hours. ICU monitoring was deemed essential due to the heightened risk of postpartum cardiovascular instability, arrhythmias, and fluid shifts in patients with severe HCM. Fortunately, no such complications arose, and the mother was transitioned to the maternity ward in stable condition. The newborn was admitted to the neonatal intensive care unit for observation due to prematurity but showed no immediate complications. Neonatology involvement ensured appropriate respiratory support and thermal regulation. Given her septal thickness ≥30 mm and documented NSVT, an ICD was placed postpartum, consistent with guideline-based risk stratification for sudden cardiac death in HCM.2 Further investigations included cardiac MRI with gadolinium to better define myocardial structure, as well as genetic testing to assess familial risk factors. Her family was subsequently screened for inherited cardiomyopathies. This case underscores several key principles in the management of severe HCM in pregnancy. First, multidisciplinary collaboration was essential in devising a management plan that addressed both maternal and fetal concerns. Second, proactive risk mitigation strategies such as ECMO preparedness and epidural anesthesia optimized maternal hemodynamics during delivery. Third, the integration of postpartum cardiac care ensured that long-term risks were addressed effectively. Ultimately, this case highlights how thoughtful planning, expert coordination, and decisive intervention can successfully guide the management of complex cardiovascular conditions during pregnancy.
