Diminished activity of the cardiac SERCA2a isoform in heart failure (HF), often accompanied by increased phospholamban (PLB)/SERCA ratio [10,11,12] and/or decreased PLB phosphorylation [12,13,14], results in slower and less complete relaxation after each beat, elevated diastolic Ca2+, and degraded cardiac function. This evidence concerns the gene PLN and hydrops fetalis.