Long QT syndrome
Protein kinase A has been implicated in a number of diseases, including cardiovascular disease, tumors of the adrenal cortex, and cancer. It has been speculated that abnormally high levels of PKA phosphorylation contributes to heart disease. This affects excitation-contraction coupling, which is a rhythmic process that controls the contraction of cardiac muscle through the synchronized actions of calcium and cAMP responsive enzymes. There is also evidence to support that the mis-localization of PKA signaling contributes to cardiac arrhythmias, specifically Long QT syndrome. This results in irregular heartbeats that can cause sudden death.