A 78-year-old woman underwent surgical intervention for severe atrial functional mitral regurgitation and left ventricular apical aneurysm secondary to apical hypertrophic cardiomyopathy. Apical hypertrophic cardiomyopathy can cause atrial fibrillation and atrial functional mitral regurgitation. Left ventricular apical aneurysms can cause fatal arrhythmias, which may require surgical intervention.