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

BACKGROUND: 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. CASE SUMMARY: 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). DISCUSSION: FCHL is often underdiagnosed due to lack of routine genetic screening and may silently progress to severe coronary disease. TAKE-HOME MESSAGES: Consider FCHL in young adults with sudden cardiac arrest or premature coronary disease. Early identification, aggressive therapy, and familial screening are crucial.