The structure and function of the helical heart and its buttress wrapping. I. The normal macroscopic structure of the heart.

The Gordian knot of anatomy has been the architectural arrangement of ventricular muscle mass, which may have finally become understood. The description of Francisco Torrent-Guasp's model of the helical heart is presented, which includes the cardiac structures that produce 2 simple loops that start at the pulmonary artery and end in the aorta. An unscrolled ventricular band is shown, achieved by blunt dissection that extends between the points of origin of the right ventricle, at the pulmonary artery root, to termination at the aortic root, in the left ventricle. These components include a spiral horizontal basal loop that surrounds the right and left ventricular cavities, and changes direction to cause a second spiral, produced by almost vertically oriented fibers, giving rise to the helical configuration of the ventricular myocardial band. These anatomic structures are successively activated, as with a peristaltic wave, starting at the right ventricle (just below the pulmonary artery) and progressing toward the aorta to produce a sequence of narrowing, caused by the basal loop contraction, shortening (related predominantly to the descendant segment contraction), lengthening (produced by the ascendant segment contraction), and widening, as a consequence of several factors that act during ventricular myocardium relaxation. These sequences control the ventricular events responsible for ejection to empty and suction to fill. These mechanical interactions of structure and function are defined in relation to chronologic location of the successive cardiac functional events in the aortic, left ventricular, and left atrial recordings.

The structure and function of the helical heart and its buttress wrapping. IV. Concepts of dynamic function from the normal macroscopic helical structure.

Torrent-Guasp's model of the helical heart is presented, which includes the cardiac muscular structures that produce 2 simple loops and that start at the pulmonary artery and end in the aorta. These components include a horizontal basal loop that surrounds the right and left ventricles, changes direction through a spiral fold in the ventricular band to cause a ventricular helix produced by now obliquely oriented fibers, forming a descending and ascending segment of the apical loop with an apical vortex. These anatomic concepts are successively activated to produce a sequence of narrowing by the basal loop, shortening by the descending segment, lengthening by the ascending segment, and widening in the cardiac cycle that causes ventricular ejection to empty and suction to fill. The factors responsible for internal torsional movements for cardiac output and suction are defined, together with mechanisms responsible for electromechanical activity produced during sequential changes in contraction and relaxation properties. These interactions of mechanical structure and function are defined in relation to pressure-related cardiac events observed from aortic, left ventricular, and left atrial recordings.

The structure and function of the helical heart and its buttress wrapping. V. Anatomic and physiologic considerations in the healthy and failing heart.

A macroscopic structure of an elliptic heart, formed by the helix provided by the apical loop, is defined and related, initially, to normal function. To define the sequence of normal progressive muscular activity, cardiac pressure, magnetic resonance imaging (MRI), and multiple gated acquisition (MUGA) records are reviewed. This novel format of structure for the helical heart is then compared with historic studies of ventricular structure. New concepts will show how the basal loops cause initial isovolumetric contraction, together with factors responsible for contractile ventricular lengthening responsible for filling by suction. The interaction of these muscular-functional changes are correlated to basic studies of electrophysiology (excitation-contraction) to set the stage for alterations produced by changing the helical apex to a sphere during congestive heart failure. Macroscopic changes in heart failure, which convert the ellipse to a globe, are defined as the underpinning of dilated cardiomyopathy. It is our hypothesis that the commonality of this spheric left ventricular substrate becomes responsible for ischemic, idiopathic, and dilated ventricular cardiomyopathy.

The structure and function of the helical heart and its buttress wrapping. VI. Geometric concepts of heart failure and use for structural correction.

The macroscopic basis for congestive heart failure is defined as conversion of a helical heart, whereby the apical loop fiber angle orientation that produces a 60% ejection fraction becomes more transverse to develop a spheric configuration. The geometric consequence is flattening of the apical loop architecture, so that the 15% shortening can produce only 30% ejection fraction. The fundamental shape change is alteration of normal relationships between the transverse basal loop and oblique apical loop, to make the apical loop become more basal through more transverse fiber orientation. These fundamental architectural changes are then used to evolve new procedures that restore a more normal, helical, ventricular architecture in ischemic and dilated cardiomyopathy. Direct intraoperative ventricular methods underlie surgical ventricular restoration or endoventricular surgical patch plasty procedures, the Batista procedure, and Pacopexy. These intraventricular objectives are then compared with external approaches without ventriculotomy (ie, reimplantation of cells, pericardial sleeve (acorn), surface radiofrequency ablation, and the myocor approaches). A survey of current direct ventricular clinical results that improve the underlying nondamaged muscle (ie, remote segment) is defined, and related to timing of procedures directed at rebuilding more normal ventricular shape before irreversible collagen and fibrosis develop. The overall intent is to convert the spheric heart into an elliptic configuration. Novel concepts are introduced to suggest an internal ventricular patch can be used as an intercavitary curtain, through covering nonscarred septal muscle (ie, normal but distended) to amplify left ventricular function through producing a more helical structure.

The structure and function of the helical heart and its buttress wrapping. VII. Critical importance of septum for right ventricular function.

The macroscopic structure of the right ventricle includes a transverse basal loop for the free wall, and oblique septal components, originating from the descending and ascending segments of the apical loop. Data is presented that determines why right ventricular function is related principally to intraventricular septal function, and why right ventricular failure is magnified by septal stunning caused by poor myocardial protection. The background of this architectural/functional change can explain normal right ventricular function, the relationship of right ventricular performance to pulmonary vascular resistance, experimental studies that characterize right ventricular performance after architectural free wall ablation, right ventricular disconnection, right coronary occlusion, and free wall replacement. These basic science studies are related to perioperative right ventricular performance, involving methods of myocardial protection, protamine reaction, right coronary occlusion and reperfusion, right ventricular dyskinesia, chronic aortic and mitral valve replacement (MVR) replacement, congenital heart disease, right and left ventricular assist devices (LVADs), and transplantation. The predominant focus is related to the septum and how it can be evaluated perioperatively. Septal evaluation by echocardiogram should become an essential feature during intraoperative management.

[Agonist-antagonist mechanics of the descendent and ascendent segments of the ventricular myocardial band]. / La mecánica agonista-antagonista de los segmentos descendente y ascendente de la banda miocárdica ventricular.

In this article the macroscopic structure of the ventricular myocardium is described, which is configurated as a band along which four segments can be distinguished. Such band traces a helicoids with two spiral turns in the space, in its trajectory from the pulmonary artery root to the aortic root, delimits both ventricular cavities. Our interest in achieving the knowledge of the coherent relationship between that anatomical fact and cardiac mechanics, which necessarily exist between the form and the function of any organ, has led us to perform some experimental approaches which show that the volume decrease of the ventricular cavities takes place, simultaneously with the descent of the base, thanks to the agonist contraction of the descending segment of the band, previously stretched out in a rectilinear way. Meanwhile, the volume increase takes place, simultaneously with the ascent of the base, as a consequence of the antagonist contraction of the ascendent segment of the band, previously extended in a curvilinear way.

[A containing prosthesis in the treatment of dilated myocardiopathy]. / Una prótesis contentiva para el tratamiento de la miocardiopatía dilatada.

A contention prosthesis is proposed for the surgical treatment of the dilated cardiomyopathy. The device of this prosthesis is based on experimental anatomical, physiological and dynamic data through which new concepts of the ventricular myocardium structure and function have been obtained.

A silicone rubber mould of the heart.

The macroscopical structure of the ventricular myocardium has been an unsolved problem since the XVIth century, when Anatomy started as an authentic science. Since then the spatial organization of the myocardial fibres has represented, as Pettigrew says, "an arrangement so unusual and perplexing, that it has long been considered as forming a kind of Gordian knot in Anatomy. Of the complexity of the arrangement I need not speak further than to say that Vesalius, Albinus, Haller and De Blainville, all confessed their-inability to unravel it". What is shown in the present paper is the result of an anatomical work, developed over 43 years, by means of which it has been shown that the ventricular myocardial mass consists of a band, curled in a helical way, which extends from the pulmonary artery to the aorta. This is illustrated by a silicone rubber model cast from an actual unrolled myocardial band.

The anisotropic structure of the human left and right ventricles.

An important determinant of cardiac output derives from the structure of the ventricular wall given by the arrangement of the cardiac muscle fibres. A key feature of this arrangement is both a global and local anisotropy. First, a preparation method necessary for analyzing the main aspects of spatial fibre architecture is outlined. Global anisotropy can be described by a gross band-like structure wrapping both left and right ventricles while local anisotropy results from the arrangement of the individual muscle fibres within the band. In pathologic cases this basic structure may be disturbed leading to cardiac failure. Second, a Finite Element model, formulated on the basis of Magnetic Resonance measurements has been devised which is intended to reflect the global as well as the local anisotropy of the ventricles in order to further the understanding of cardiac performance.

[4 proposals for ventricular remodelling in the surgical treatment of dilated myocardiopathy]. / Cuatro propuestas para la remodelación ventricular en el tratamiento quirúrgico de la miocardiopatía dilatada.

Four surgical procedures are proposed to achieve an efficient remodelling of the ventricles with a low injury to heart muscle, for the treatment of the dilated cardiomyopathy. Those procedures are based the partial ventriculectomy technique of Batista an on the new conception of the macroscopical myocardium structure of the ventricles evidenced in the second half of the present century.

[Elastic]. / Un modelo elástico del corazón.

Since the ventricular myocardium is made up of a band of myocardial fibres which are configured into a complicated three-dimensional helical way, some time spent handling and observing this teaching model can help any cardiologist involved in imaging methods to understand and interpret the structural basis of the motion patterns of the heart. We concede that we need the cooperation of all disciplines to elucidate functional understanding of the myocardial band structure described above.

The difficult access to morphology of the heart: clinical implications.

The literature on the morphology of the heart is reviewed within the context of recent histological findings. There is strong evidence for a dualistic myocardial function, whereby both ventricular constricting and expanding forces are supposed to act synchronously although with variable effect over the heart cycle.The morphological basis of this dualistic myocardial function is the contorted rope-like structure worn into the bulk of the heart muscle. Opinions are divided about the invasiveness of blunt preparation on the heat denatured heart by which the fascicular architecture is carved out of the muscle. Histology confirms the existence of a fascicular substructure. It results from an inhomogeneous repartition of myocardial fibre branchings and the arrangement of the delicate connective tissue netting by which myocardial strands are bundled and wrapped. One important feature of the fascicular structure of the heart muscle is an oblique transmurally arranged element which yields a force vector opposing systolic wall thickening. This structural element which acts in the direction of ventricular dilation probably gains pathological import in some cases of architectural remodelling, namely in myocardial fibrosis and hypertrophy.