paeds587

paeds587

A 14-year-old female was found to have a 1/6 systolic ejection murmur on regular check-up and was subsequently referred to a cardiologist. A thorough physical examination reveals long upper extremities with thin slender fingers, with a high arched palate and excessive ligamentous laxity. Her thumb can be bent back easily to touch her radius. ECG reveals sinus bradycardia that is consistent with aerobic conditioning. She also had an echo done. In reference to her most likely diagnosis, which of the following is the most serious cardiac complication associated to this condition?