The vectorial organization of the human myocardium is designed for optimal electrical and contractile activity: clinical implications of its alterations

The organization of human myocardium is reviewed at tissue, cellular and molecular level to understand the design that allows highly vectorial activities such as contraction of the cardiac pump and the electrical activity underlying its coordination. This may contribute to clarify the pathogenesis of severe human diseases such as arrhythmias, cardiomyopathies and cardiac insufficiency and failure. Amazingly, it appears that twisted helical structures are formed by molecules or by cells aimed to produce an efficient and highly coordinated contractile activity which is needed for the propulsion of the blood from the North of the atria to the South of the ventricles and then to the blood vessel tree. Mutations of monomeric proteins, their immature isoforms, and perturbing extraneous molecules can lead to abnormal organizations of crucial supramolecular structures (sarcomeric disarray, alteration of intercalated discs, abnormal gap junctions, myocardial fascicula) which results in an abnormal clinical function.