A New Coding System for the Identification of Left Ventricular Rotation Patterns and Their Relevance to Myocardial Function.

Rotational mechanics is a fundamental determinant of left ventricular ejection fraction (LVEF). The coding system currently employed in clinical practice does not distinguish between rotational patterns. We propose an alternative coding system that makes possible to identify the rotational pattern of the LV and relate it to myocardial function. Echocardiographic images were used to generate speckle tracking-derived transmural global longitudinal strain (tGLS) and rotational parameters. The existence of twist (basal and apical rotations in opposite directions) is expressed as a rotational gradient with a positive value that is the sum of the basal and apical rotation angles. Conversely, when there is rigid rotation (basal and apical rotations in the same direction) the resulting gradient is assigned a negative value that is the subtraction between the two rotation angles. The rotational patterns were evaluated in 87 healthy subjects and 248 patients with LV hypertrophy (LVH) and contrasted with their myocardial function. Our approach allowed us to distinguish between the different rotational patterns. Twist pattern was present in healthy controls and 104 patients with LVH and normal myocardial function (tGLS ≥ 17%, both). Among 144 patients with LVH and myocardial dysfunction (tGLS < 17%), twist was detected in 83.3% and rigid rotation in 16.7%. LVEF was < 50% in 34.7%, and all patients with rigid rotation had a LVEF < 50%. The gradient rotational values showed a close relationship with LVEF (r = 0.73; p < 0.001). The proposed coding system allows us to identify the rotational patterns of the LV and to relate their values with LVEF.

El fulcro cardíaco y su relación con el nódulo auriculoventricular / Cardiac Fulcrum, its Relationship with the Atrioventricular Node

RESUMEN Introducción. El estudio de la anatomía funcional del miocardio helicoidal continuo permite visualizar su inicio y fin en el nacimiento de los grandes vasos. En nuestras investigaciones siempre hemos considerado que debía tener un punto de unión que permitiera su rotación helicoidal para cumplir los movimientos fundamentales de acortamiento-torsión (sístole) y alargamiento-destorsión (succión). Una vez encontrado, se le llamó fulcro cardíaco. Objetivos. Esta investigación tiene como objeto describir y entender la interrelación entre el fulcro cardíaco y el nódulo auriculoventricular de Aschoff-Tawara Material y métodos. Se utilizaron 31 corazones procedentes de la morgue y del matadero: 17 correspondieron a bóvidos y 14 a seres humanos. Resultados. En nuestras investigaciones hemos demostrado que el soporte del miocardio, denominado fulcro cardíaco, que se localiza en el trayecto del segmento septal del anillo aórtico y se extiende desde el trígono izquierdo hasta el derecho por debajo del origen de la arteria coronaria derecha, es adyacente al nódulo auriculoventricular (AV). Otro aspecto importante de esta posición contigua es que el fulcro está rodeado, e incluso invadido, por un plexo nervioso interconectado con el nódulo. Conclusión. Esta descripción del fulcro cardíaco pondría fin al problema de la falta de apoyo del miocardio para cumplir su función de torsión/destorsión. La proximidad del fulcro al nódulo AV y la penetración de los plexos nerviosos en el apoyo indican la existencia de una unidad electromecánica, que hemos investigado en función de la anatomía helicoidal del corazón. Hemos comprobado una mejor estimulación cardíaca cuando el catéter se coloca en el infundíbulo ventricular derecho.

ABSTRACT 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.

Myocardial Wringing and Rigid Rotation in Cardiac Amyloidosis.

Background: The motion of the heart is a result of the helicoidal arrangement of the myofibers in the organ's wall. We aimed to study the relationship between the wringing motion state and the degree of ventricular function in patients with cardiac amyloidosis (CA). Methods: Fifty patients with CA and decreased global longitudinal strain (LS) were evaluated using 2-dimensional speckle-tracking echocardiography. We have expressed LS as positive values to facilitate understanding. Normal twist, which occurs when basal and apical rotations occur in opposite directions, was coded as positive. When the apex and base rotate in the same direction (rigid rotation), twist was coded as negative. Left ventricular (LV) wringing (calculated as twist/LS, which takes into account actions that occur simultaneously during LV systole [ie, longitudinal shortening and twist]) was evaluated according to LV ejection fraction (LVEF). Results: Most of the patients (66%) who participated in the study were diagnosed with transthyretin amyloidosis. A positive relationship was observed between wringing and LVEF (r = 0.75, P < 0.0001). In advanced stages of ventricular dysfunction, rigid rotation appeared in 66.6% of patients with LVEF ≤ 40%, in whom negative values of twist and wringing were observed. LV wringing proved to be a good discriminator of LVEF (area under the curve 0.90, P < 0.001, 95% confidence interval 0.79-0.97); for example, wringing < 1.30°/% detected LVEF < 50% with 85.7% sensibility and 89.7% specificity. Conclusions: Wringing, which integrates twist and simultaneous LV longitudinal shortening, is a conditioning rotational parameter of the degree of ventricular function in patients with CA.

Contexte: Les mouvements du cœur sont le résultat de l'orientation hélicoïdale des fibres des parois du cœur. L'objectif de notre étude était d'étudier le lien entre le mouvement « d'essorage ¼ et la fonction ventriculaire chez les patients atteints d'amylose cardiaque (AC). Méthodologie: Cinquante patients atteints d'AC et présentant une déformation longitudinale (DL) globale réduite ont fait l'objet d'une évaluation à l'aide de l'échocardiographie bidimensionnelle de suivi des marqueurs acoustiques. Nous avons choisi d'exprimer la DL en valeurs positives pour faciliter la compréhension des données. Une torsion normale, caractérisée par les mouvements de rotation opposés entre la base et l'apex du cœur, a été codée comme positive. Lorsque l'apex et la base opéraient une rotation dans la même direction (rotation rigide), la torsion était codée comme négative. Le mouvement « d'essorage ¼ du ventricule gauche (VG) (calculé comme le rapport torsion/DL, qui tient compte des actions survenant simultanément durant la systole du VG [c.-à-d., raccourcissement longitudinal et torsion]) a été évalué en fonction de la fraction d'éjection du VG (FEVG). Résultats: La plupart des patients (66 %) ayant participé à l'étude avaient reçu un diagnostic d'amylose à transthyrétine. Un lien positif a été établi entre le mouvement d'essorage et la FEVG (coefficient de corrélation [r] = 0,75, p < 0,0001). Aux stades avancés de la dysfonction ventriculaire, une rotation rigide a été observée chez 66,6 % des patients ayant une FEVG ≤ 40 % et chez qui les valeurs de torsion et d'essorage étaient négatives. L'essorage du VG s'est révélé être un facteur fiable de détermination de la FEVG (aire sous la courbe : 0,90; p < 0,001, intervalle de confiance [IC] à 95 % : 0,79-0,97); par exemple, un mouvement d'essorage < 1,30 °/% a permis de détecter une FEVG < 50 % avec une sensibilité de 85,7 % et une spécificité de 89,7 %. Conclusions: Le mouvement d'essorage, qui intègre simultanément la torsion et le raccourcissement longitudinal du VG, est un paramètre rotationnel qui influence le degré de fonction ventriculaire chez les patients atteints d'AC.

Investigación anatómica del ápex cardíaco / Anatomical investigation of the cardiac ápex

RESUMEN Objetivo: Comprender la anatomía cardíaca es la clave para resolver incógnitas sobre su función. La estructura miocárdica continua y helicoidal desempeña un papel fundamental en los movimientos de torsión-detorsión. El ápex, parte constitutiva del ventrículo, ¿tiene relevancia en la dinámica cardíaca o es simplemente un fondo de saco? El objetivo del presente trabajo fue responder este interrogante. Material y métodos: Se utilizaron para los estudios anátomo-histológicos cuatro corazones de bovinos jóvenes y cuatro corazones humanos (dos embriones y dos adultos). Para esta investigación se realizaron dos procedimientos: a) desplegamiento del miocardio continuo para observar la disposición de las fibras en la punta del ventrículo izquierdo, denominada zona apexiana; b) cortes horizontales y longitudinales para estudiar la estructura del ápex. Los primeros se realizaron entre los 2/3 medio y apexiano, y los longitudinales seccionando la punta ventricular izquierda con una orientación ápex-base. Resultados: Hemos encontrado en todos los corazones humanos y bovinos estudiados que el ápex corresponde únicamente al ventrículo izquierdo, en donde se ubica el giro del segmento descendente en la continuidad ascendente del miocardio continuo. El fondo de saco apexiano no posee prácticamente plano muscular en su extremo final. Está tapizado por dentro por el endocardio y por fuera por el epicardio. El plano muscular es apenas un 10% en espesor del miocardio contiguo. La transiluminación reafirma este concepto estructural. Conclusiones: El ápex es un fondo de saco prácticamente sin músculo, en el que el endocardio y el epicardio se hallan adosados, pero que cumple funciones del soporte de las presiones intraventriculares y es parte constitutiva de los movimientos de torsión y detorsión.

ABSTRACT Objective: Understanding cardiac anatomy is the key to solve unknown issues about its function. The continuous and helical myocardial structure plays a fundamental role in its torsion-detorsion motions. Does the apex, a constitutive part of the ventricle, have relevance in cardiac dynamics or is it simply a cul-de-sac? The aim of this study was to answer this question. Methods: Four young bovine and four human hearts (two embryos and two adults) were used for the anatomo-histological studies. Two procedures were carried out for this investigation: a) the continuous myocardium unfolding to observe the fiber arrangement at the tip of the left ventricle, called the apical zone; and b) horizontal and longitudinal sections to study the structure of the apex. The horizontal sections were performed between the middle 2/3 and the apex, and the longitudinal ones, sectioning left ventricular apex, with an apex-base orientation. Results: In all the human and bovine hearts studied we found that the apex corresponds only to the left ventricle, where the twist of the descending segment is located, in the ascending continuity of the myocardium. The apical cul-de-sac has practically no muscular plane at its end. It is internally lined by the endocardium and externally by the epicardium. The muscular plane has only 10% thickness of the adjacent myocardium, a structural concept confirmed by transillumination. Conclusions: The apex is a cul-de-sac practically devoid of muscle, in which the endocardium and epicardium are attached, but which performs the functions of supporting intraventricular pressures and being a constitutive part of the torsion and detorsion motions.