Mitral valve chord rupture in a pregnant patient with uncontrolled hyperthyroidism

Graves' disease can have multiple cardiac manifestations. A rare complication is that of severe mitral regurgitation secondary to mitral valve chordae rupture, due to both compromise of valve integrity by deposition of glycosaminoglycans and the hemodynamic stresses of thyrotoxicosis. Pregnancy, with its related hemodynamic changes, is another setting in which mitral valve chordae rupture has occasionally been documented. We present a unique case of a 36-year-old female with uncontrolled Graves' disease who presented during pregnancy at 13 weeks gestation with atrial flutter and features of congestive heart failure. Echocardiogram found severe mitral regurgitation secondary to a ruptured mitral chord. She was treated conservatively with diuresis and ultimately delivered her baby without complication at 28 weeks when she had preterm premature rupture of membranes. She is currently on methimazole and propranolol and pending definitive management of her Graves' disease. This represents not only a rare cardiac complication in a patient with Graves' disease but also is the first in the literature, to our knowledge, which describes this complication in a pregnant patient with Graves' disease.

Thyroid disease can have multiple effects on the heart through hemodynamic and structural changes and can result in heart failure, arrhythmias, valvular disease, and pulmonary hypertension. Graves' disease can cause glycosaminoglycan deposition in valvular tissue resulting in fragile leaflets that can rupture with little stress. Pregnancy and thyrotoxicosis have similar hemodynamic consequences with increased cardiac output and reduced systemic vascular resistance. Be vigilant in those with hyperthyroidism with a new murmur or features of acute heart failure, as a ruptured valve chord can result in increased morbidity and mortality if not recognized and addressed quickly.