Upregulation of cardiomyocyte ribonucleotide reductase increases intracellular 2 deoxy-ATP, contractility, and relaxation

► dATP enhances myocardial contraction via increased crossbridge binding and kinetics. ► [dATP] can be increased > 10-fold via ribonucleotide reductase (Rrm) overxpression. ► Rrm overexpression increased intact cardiomyocyte contractility and relaxation. ► Rrm overexpression had no effect on Ca2+ transient magnitude. ► Myofilament targeted gene manipulations can improve cardiac function.