Case Presentation: A 30-year-old man with no significant medical history was brought to the ED for a ventricular fibrillation (VF) arrest after he was hit in the chest by a soccer ball during a game. After successful resuscitation, exam was notable for a 3/6 systolic murmur heard in the 5th intercostal space at the left sternal border. Electrocardiogram showed left ventricular hypertrophy with ST elevations in V1 and V2. Echocardiogram revealed severe left ventricular hypertrophy, diastolic dysfunction, and systolic anterior motion of the mitral valve with left ventricular outflow tract obstruction and a gradient of 111 mmHg. A dual-chamber AICD was placed prior to discharge. Metoprolol and disopyramide were started for HCM management. The patient tolerated the procedure well; he was discharged home with outpatient cardiology follow up and continues to do well with no further cardiac events.
Discussion: Commotio cordis (CC) is a potentially fatal mechano-electric syndrome and the second most common cause of sudden cardiac death in young athletes after hypertrophic cardiomyopathy (HCM). Both conditions are rare, and their coexistence in one patient is even more so.Both HCM and CC can cause VF , but their mechanism of action is different. For example, the immediate trigger for VF in CC is likely a focal phenomenon induced by direct impact, similar to a premature ventricular contraction seen in electrophysiology labs or cardiac catheterization procedures. Alternatively, it could be an afterdepolarization induced by changes in current flow, similar to the R-on-T phenomenon observed in acute ischemia or in long-QT syndrome. On the other hand, in HCM , the obstruction is dependent on contractility and loading conditions and may lead to ventricular arrhythmias and sudden death due to increased myocardial ischemia.
Conclusions: In this case although the history was suggestive of CC as a cause of VF, the accidental discovery of HCM introduces ambiguity to accurately identify the primary cause of VF. HCM has not been posited as a risk factor for CC, but given the lack of consensus around the mechanism of CC, it is difficult to state with certainty that there is no association between these two rare cardiac conditions.