A method for regulating in vivo calcium transport in cardiac muscle of animals suffering from congestive heart failure is disclosed. According to the method, calcium ATPase activity (which decreases as congestive heart failure develops) and cardiac muscle contractility augmented by delivering a gene which operatively encodes the enzyme into the heart. Delivery systems, including but not limited to using adeno-associated viral vectors are provided. Methods for monitoring the expression and effect of the gene product on cardiac performance are also provided.