Background.

The functional anatomy of the helical, continuous myocardium allows envisioning that it initiates and ends at the origin of the great vessels. In our research, we have always considered that it should have a point of attachment to allow its helical rotation to fulfill the fundamental movements of shortening-torsion (systole) and lengthening-detorsion (suction), which once found, was called the cardiac fulcrum.

Objectives.

The research aims to describe the important aspect of understanding the interrelationship between the cardiac fulcrum and the Aschoff-Tawara atrioventricular node

Material and Methods.

A total of 31 hearts, arising from the morgue and slaughterhouse were used: 17 corresponded to bovids and 14 were human.

Results.

Our investigations have shown that the myocardial support termed cardiac fulcrum, located in the trajectory of the aortic annulus septal segment, extending from the left to the right trigone and below the origin of the right coronary artery, is adjacent to the AV node. Another important aspect of this contiguous position is that the fulcrum is surrounded, and even invaded, by a rich nervous plexus interconnected with the node.

Conclusion.

This description of the cardiac fulcrum would end the problem of lack of support of the myocardium to fulfill its function of torsion/detorsion. The proximity of the fulcrum to the AV node and the penetration of the nervous plexuses in the support suggest an electromechanical unit, which we have investigated according to the helical anatomy of the heart, establishing an improved cardiac stimulation with a catheter placed in the right ventricular outflow tract.