Cardiac metabolism and arrhythmias.

Sudden cardiac death remains a leading cause of death in the Western world, accounting for up to 20% of all deaths in the United States1,2 The major causes of sudden cardiac death in adults age 35 and older are coronary artery disease (70% to 80%) and dilated cardiomyopathy (10% to 15%).3 At the molecular level, a wide variety of mechanisms contribute to arrhythmias that cause sudden cardiac death, ranging from genetic predisposition (rare mutations and common polymorphisms in ion channels and structural proteins) to acquired electrophysiological and structural remodeling in left ventricular hypertrophy and failure.4,5 A growing body of evidence suggests that altered ion channel function is closely linked to changes in metabolic activity in a wide variety of pathological conditions. In this review we focus on the mechanisms by which altered metabolic function affects cardiac electrophysiology. We will review the specific molecular targets that allow cardiomyocytes to recognize alterations in their metabolic state and translate this information into changes in membrane excitability in various pathophysiological conditions including ischemia-reperfusion, heart failure (HF), left ventricular (LV) hypertrophy, diabetic cardiomyopathy, and atrial fibrillation (AF). A comprehensive understanding of the interrelated processes of metabolic and electric remodeling promises to identify new molecular targets for the treatment of cardiac arrhythmias.