The intracellular pH and the buffer capacity of the heart

The intracellular buffering (delta HCO3-/delta pH) in rats is lowest in skeletal muscle, intermediate in the diaphragm and highest in cardiac muscle. In the hypertrophic heart due to aortic constriction or to the Goldblatt mechanism the buffer value increases markedly during the first weeks, but returns to normal or even subnormal values during stable hypertrophy. There is an electrochemical disequilibrium for hydrogen ions caused by an active transport of ions across the cell membrane, which is possibly correlated to the myocardial activity.