Spinal anesthesia in the setting of apical-septal variant right ventricular hypertrophy with enlarged right atrium
Abstract Number: F-52
Abstract Type: Case Report/Case Series
A 35 year old G6P4 woman presented to the emergency department at 23 weeks gestation with chest pain, syncope, tachycardia, and tachypnea. Non-sustained ventricular tachycardia was recorded. Echocardiogram showed normal ejection fraction and right atrial dilation. Chest CT ruled out pulmonary embolus but showed marked enlargement of the right atrium and inferior vena cava and concentric thickening of the myocardium involving mid and distal septum extending to the right ventricular apex. By cardiac magnetic resonance imaging the thickened segment was composed of myocardium with uniform perfusion. The contractile segments of the base of the right ventricle and its outflow track were also thickened. There was marked right atrial and inferior vena caval enlargement and tricuspid regurgitation.
The patient required repeat cesarean for failure to progress at 39 weeks, 6 days. She had a Mallampati 3 airway. An intrathecal dose of 12 mg bupivacaine and 15 mcg fentanyl was injected at L4/L5 interspace with a 25 g whitacre spinal needle resulting in a T6 sensory level. She was positioned supine with left uterine displacement. Lactated ringer's was run continously and phenylephrine was bolused liberally to counteract sympathectomy. She was maintained on her recently prescribed metoprolol.
Hypertrophic cardiomyopathy (HCM) is most commonly a genetic condition that affects the left ventricle, affecting as many as 1:500 people. Left sided HCM can be associated with dynamic obstruction of the outflow tract leading to significant reduction in cardiac output with decreased intravascular volume or tachycardia. Reports of isolated right sided HCM are rare; we believe this is the first recorded in a pregnant patient. Neuraxial techniques have been performed safely in patients with left sided HCM in the setting of appropriate monitoring. We have safely performed spinal anesthesia in one patient with apical (non-obstructive) right ventricular hypertrophy using beta blockers and aggressive IV fluids and alpha agonists to achieve rate control as well as maintenance of adequate preload and afterload.
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