Biology and the role of mechanoelectric feedback in the heart (Q1266808)

Excitation contraction coupling in ventricular muscle, where electrophysiological changes initiate mechanical changes, has been extensively investigated. Mechanoelectric feedback (MEF), where electrophysiological changes follow mechanical changes, is less well understood. This paper contains an extensive bibliography on MEF -- not all papers in the reference section are referred to in the text. The existence of myocardial mechanosensitivity and MEF should not be too surprising. The heart undergoes profound changes in mechanical wall stress and strain, with a time course comparable to the electrical changes that initiate them. Interaction between excitation-contraction coupling (ECC) and MEF would produce fine tuning of the regulatory processes in myocardium. Moreover, disturbances in this tuning by pathological processes that induce mechanical changes in the heart should produce clinical syndromes, and evidence is accumulating that this could be the case. Although heart disease together with ventricular arrhythmia is a potent cause of death in the Western world the mechanisms are unclear and the treatment unsatisfactory. It is striking that these arrhythmias parallel the degree of myocardial mechanical dysfunction rather than the electrophysiological changes. Finally, any theoretical studies incorporating MEF should produce models or results in keeping with experimental findings, or have some predictive value.