Sudden Cardiac Arrest as Initial Presentation of Familial Combined Hyperlipidemia in a Young Adult

Familial combined hyperlipidemia (FCHL) affects 0.5% to 2% of the population and is a significant risk factor for premature myocardial infarction, accounting for up to 16% of cases.

A 46-year-old man experienced cardiac arrest while surfing. Emergency services found him pulseless with ventricular fibrillation requiring 2 defibrillations and 10 minutes of resuscitation before return of spontaneous circulation. Bloodwork revealed severe dyslipidemia (low-density lipoprotein cholesterol 358 mg/dL, triglycerides 1,622 mg/dL) consistent with FCHL. Coronary angiography demonstrated triple-vessel disease, requiring coronary artery bypass grafting. He received multimodal lipid-lowering therapy and subcutaneous implantable cardioverter-defibrillator. At 3 months, there was dramatic improvement in dyslipidemia (low-density lipoprotein cholesterol 52 mg/dL, triglycerides 232 mg/dL).

FCHL is often underdiagnosed due to lack of routine genetic screening and may silently progress to severe coronary disease.

Consider FCHL in young adults with sudden cardiac arrest or premature coronary disease. Early identification, aggressive therapy, and familial screening are crucial.