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Introduction/Objectives: In the cardiac cycle, should a coupling phase be considered between systole and diastole where cardiac suction occurs? Shouldn't the left ventricular ejection fraction be considered a poor reliability index? According to these considerations, would it not be more logical to speak of cardiac energy of suction and ejection as parameters that summarize the cardiac potential and to which variables that are not independent would concur. Materials and Methods: The concept of energy is incorporated by means of a detailed evaluation of the cardiac ability developed by both ventricles as a counterpart of ejection fraction values to assess ventricular function. The heart in its pump function, presents a dynamic effect that is greater than the volume it ejects. Data involving patients will have informed consent. Results: Understanding the active mechanism of the suction phase as a link between systole and diastole opens a wide scenario on surgical techniques and medical treatments for many cardiac diseases that are still the focus of attention. Conclusion: The important incorporation of other disciplines such as physics and hydraulics has allowed the evaluation of cardiac mechanics from pre-existing laws that denote and justify what the heart really represents: a mechanical suction pump. The understanding of cardiac functions is achieved from the cardiac structure-function and from a physico/hydraulic point of view.

The aim of this study was to investigate: a) beginning and ends of the myocardium; b) the slippage between the myocardial segments implies that there should be an antifriction mechanism; c) the electrical activation of the endocardial and epicardial segments; d) the mechanism of active suction during the diastolic isovolumic phase. Ten young-bovine hearts and eight human hearts were used for anatomical- histological analysis and five patients with normal QRS complexes underwent threedimensional endoepicardial electroanatomic mapping. A nucleus (cardiac fulcrum) underlying the right trigone was found in all the hearts. Hyaluronic acid was found in the cleavage planes between the myocardial bundles. Endo-epicardial mapping demonstrated an electrical activation sequence consistent with the mechanism of ventricular twist. The finding of the fulcrum provides support to the spiral myocardial muscle. The hyaluronic acid would act as a lubricant. Electrophysiological studies explain the ventricular twist and the active suction mechanism.

RESUMEN Objetivo: El músculo cardíaco no puede estar anatómicamente libre en el tórax y sin un soporte para cumplir con su función hemodinámica. Por tanto, se analizó la posibilidad de la existencia de un punto de apoyo que actuara a modo de palanca. Material y métodos: Se utilizaron: 1) disección cardíaca en diez corazones bovinos jóvenes (dos años) (800-1000 g); 2) disección cardíaca en ocho corazones humanos: un embrión de 23 semanas de gestación; uno de 10 años, 250 g; y seis adultos, peso medio 300 g. La banda miocárdica se desenrolló en su totalidad. Las piezas extraídas fueron analizadas por anatomía e histología. Se completó la investigación con estudios de imágenenes radiograficas simples, resonancia nuclear magnética y tomografia computada. Resultados: En investigaciones anatómicas hemos encontrado en todos los corazones humanos y bovinos estudiados un núcleo subyacente al trígono derecho de estructura histológica ósea-condroide-tendinosa. El análisis microscópico reveló en corazones bovinos una matriz osteocondral trabecular (fulcro). En todos los corazones humanos se encontró que el fulcro se halla formado por tejido condroide. En esta estructura, no descrita por otros autores, tienen inserción muscular el origen y el final de las fibras miocárdicas. Las técnicas con imágenes confirmaron su existencia. Conclusiones: El fulcro cardíaco encontrado en la investigación anatómica de corazones humanos y bovinos aclararía sobre el necesario punto de apoyo del músculo miocárdico para completar sus movimientos de torsión. ABSTRACT Objective: The cardiac muscle cannot be anatomically free in the thorax. Therefore, it was thought and analyzed that there could be a myocardial support point (lever fulcrum). Material and Methods: Cardiac dissection in ten young (two years old) bovine hearts (800-1000 g); and in eight human hearts ( one embryo, 4 g; one 10 years old, 250 g; and six adult, mean weight 300 g) were performed. The myocardial band was unrolled in its entirety. The extracted pieces were analyzed by anatomy and histology. A study with magnetic resonance images, tomography and simple radiology was also carried out. Results: In anatomical investigations we have found in all the human and bovine hearts studied a nucleus underlying the right trigone of bone, chondroid or tendon histological structure. The microscopic analysis revealed in bovine hearts a trabecular osteochondral matrix (fulcrum). In the ten year old human heart and in the fetus, a central area of the fulcrum formed by chondroid tissue was found. Histology found a tendon matrix in adult human hearts. This fulcrum is attached to the myocardium and would serve to support both the origin and the end of the myocardium. The images showed evidence of the cardiac fulcrum. Conclusions: The cardiac fulcrum found in the anatomical investigation of bovine and human hearts would clarify the point of support of the myocardial muscle to complete its rotating function.