Early Detection of Pediatric Hypertrophic Obstructive Cardiomyopathy (HOCM) Utilizing Focused Cardiac Point-of-Care Ultrasound (POCUS) in the Emergency Department (ED): Beyond EKG and Stethoscope: An Abstract from Akron Children’s Hospital Resident and Fellow Academic Day

Syncope accounts for nearly 3% of all pediatric ED visits, and more than 70% are attributed to autonomic causes. However, approximately 3-4 % of pediatric syncope patients are cardiac in origin and are likely related to structural heart disease, myocardial dysfunction, or dysrhythmias.1 Early recognition is critical as they are associated with high mortality and morbidity. Hypertrophic Obstructive Cardiomyopathy (HOCM) is the most common inherited cardiomyopathy and is characterized by unexplained left ventricular hypertrophy in the absence of other identifiable causes. Clinical presentation varies widely, ranging from completely asymptomatic to sudden death, and is related to the degree of left ventricular outflow obstruction. 2 Early diagnosis in the ED can be challenging given limited access to echocardiogram or cardiac MRI, and early diagnostic tests are often nonspecific. An 11-year-old male with a history of autism and ADHD on methylphenidate presented after a syncopal episode in school preceded by multiple episodes of orthostatic presyncope that morning. He denied chest pain, dyspnea, cough, or fever. Family history significant for HOCM with sudden cardiac death in maternal grandmother at age 40, and maternal cousin who died in infancy from HOCM. The patient’s mother had valvular heart disease, and her sister had cardiomyopathy. On arrival, the patient appeared hemodynamically stable but had significant orthostatic tachycardia and otherwise normal examination findings. Initial differentials included arrhythmia, dehydration, orthostatic hypotension, viral prodrome, and myocarditis. EKG demonstrated NSR without ischemic changes, conduction abnormalities, or prolonged QTc. Lab evaluation revealed mild elevation of troponin 25.4 ng/l (normal <14ng/l) but normal range d-dimer and negative CTA of chest for embolus. Focused cardiac POCUS performed in the ED revealed asymmetrical septal hypertrophy with concern for mild LVOT obstruction, prompting cardiology consultation and admission to the PICU. A comprehensive echocardiogram and cardiac MRI confirmed asymmetric septal hypertrophy with hyperdynamic systolic function and no significant left ventricular outflow obstruction. The patient began treatment with beta-blockers. An ambulatory monitoring device revealed multiple episodes of non-sustained monomorphic ventricular tachycardia. An implantable cardioverter-defibrillator (ICD) placement was recommended by cardiology due to high risk factors, but the family declined given an unpleasant experience with the grandmother’s ICD. The patient was discharged home with an external automated defibrillator and routine follow-up with cardiology.