Direct inhibition of sodium/hydrogen (NHE-1) and sodium/calcium transporters in cardiac myocytes alters ion homeostasis, thus reversing cardiac injury, reducing myocardial hypertrophy, fibrosis, and the risk of arrhythmia, while improving remodeling to sustain left ventricular improvement in systolic function. This evidence concerns the gene SLC9A1 and cardiac arrhythmia.