What Is the Heart? Anatomy, Function, Pathophysiology, and Misconceptions

Abstract

Cardiac dynamics are traditionally linked to a left ventricle, right ventricle, and septum morphology, a topography that differs from the heart's five-century-old anatomic description of containing a helix and circumferential wrap architectural configuration. Torrent Guasp's helical ventricular myocardial band (HVMB) defines this anatomy and its structure, and explains why the heart's six dynamic actions of narrowing, shortening, lengthening, widening, twisting, and uncoiling happen. The described structural findings will raise questions about deductions guiding "accepted cardiac mechanics", and their functional aspects will challenge and overturn them. These suppositions include the LV, RV, and septum description, timing of mitral valve opening, isovolumic relaxation period, reasons for torsion/twisting, untwisting, reasons for longitudinal and circumferential strain, echocardiographic sub segmentation, resynchronization, RV function dynamics, diastolic dysfunction's cause, and unrecognized septum impairment. Torrent Guasp's revolutionary contributions may alter future understanding of the diagnosis and treatment of cardiac disease.

Keywords: RV function; conventional heart anatomy; diastolic dysfunction; helical ventricular myocardial band; isovolumic relaxation time; mitral valve opening.

Figure 1

(a) Helical ventricular myocardial band unfolding. Upper left—intact heart. Upper right—circumferential or basal loop unfolding its right segment. Second layer—further circumferential or basal loop unfolding of its left segment and showing inner helix. Third layer—helix unfolding to display descending segment (DS) after ascending segment (AS) is separated. The entire basal loop (containing RS and LS) is also shown. Bottom layer—HMVB unraveled to display its rope-like model appearance. Longitudinal fibers only exist within the two papillary muscles; (b) unfolding of HVMB model. Upper left—intact heart. Upper right—circumferential wrap or basal loop with transverse fibers and the inner helix. Lower right—unfolded helix showing the oblique fibers of the inner descending helical arm that is separated from the outer ascending helical arm. Lower right—outer ascending helical arm. Marker arrow points to the left anterior descending artery pathway that bisects the helical muscles forming septum and left ventricular free wall. Reproduced form the references [6,8] with Publisher’s permission.

Figure 2

Apical view of heart muscle showing the fibers clockwise and counterclockwise spiral formation. Images display common anatomy from Lower in 1669 (left), and Torrent Guasp in 1970 (right). Reproduced form the reference [17] with Publisher’s permission.

Figure 3

Human myocardial fibrillogenesis: (a) 1 and 2 show DT-MRI during the myocardial fibrillogenesis (gradual increase in number and spatial helical arrangement) of the ventricular myocardial fibers in human embryo at 10 and 14 weeks, respectively; (b) DT-MRI in adult heart showing helical right handed helix (red), left handed helix (green/yellow) and blue circumferential or horizontal fibers with zero helix. Note absent circumferential fibers in septum. Reproduced form the references [8,24] with Publisher’s permission.

Figure 4

Doppler longitudinal strain imaging of septum (right and left sides) in apical four-chamber view. Longitudinal strain marked by red (right) and green (left) circles, showing deformation in opposite directions on right and left septum sides—relative to baseline zero value. Timing shows LV first and RV second. SR, Strain rate; AVC, aortic valve closure; RV, right ventricle; LV, left ventricle. Reproduced form the reference [38] with Publisher’s permission.

Figure 5

Computerized Ttomography of cardiac short axis, at mid ventricle level, following air insufflation to separate collagen scaffold netting. Plane between the two septum muscle mass rims reflects the echogenic line in septum, and Supplementary Video S4 records motion between these post mortem rims. Reproduced form the reference [39] with Publisher’s permission.

Figure 6

(a) Mid-septal hyperechogenic line shown in low and high-resolution echocardiogram; (b) septum high-resolution ultrasound image at transducer frequency (12 MHz), displaying its bilayer line with inner dimension structure of 100 to 150 μm. Working septum muscle fibers display different directionality on either side of septum line. This disappears, as does the echogenic line—when cardioplegia (cardiac arrest) stops contractile function. Reproduced form the reference [8] with Publisher’s permission.

Figure 7

Upper left shows intact heart containing a basal loop (circumferential wrap with right (RS) and left (LS) segments) and helix (dark color) with descending (DS) and ascending (AS) segments. Lower left—diastole without contraction. Lower middle—displays shows torsion (twisting) with stronger contraction of descending helical arm (tighter coils), and stretching of ascending helical arm. Lower right—recoil with global clockwise rotation; note lengthening due to ongoing contraction of ascending helical arm. Upper drawing—cobra shows similar elongation from its contracting muscle. Reproduced form the reference [17] with Publisher’s permission.

Figure 8

Physiologic observations in all texts and medical journals, showing mitral valve opening (MVO) when LV pressure falls below left atrial pressure, and that the isovolumic relaxation phase exists between aortic valve closure and MVO. Reproduced form the reference [6] with Publisher’s permission.

Figure 9

(a) Mitral valve apparatus composed of fixed annulus and mobile leaflets, chordae tendineae, papillary muscles, and ventricular wall; (b) Mall’s 1911 report showing how apical counterclockwise rotation of the apex shuts the valve during torsion—by bringing spiral papillary muscles together. Mitral valve inflow area opens during from its clockwise rotation during recoil. Reproduced form the reference [56] with Publisher’s permission.

Figure 10

Left ventricular contraction sequence by anterior LV sonomicrometer crystals. Blue shading shows pre ejection isovolumic interval, yellow shading shows post ejection recoil. Note (a) ascending helical arm does not contract during pre-ejection, but contracts during recoil; (b) negative dP/dt is yardstick for starting recoil, and marks when inner helical arm stops contracting. Reproduced form the reference [6] with Publisher’s permission.

Figure 11

Torsion. The bioengineering approach (upper left) shows it develops ‘within each helix’; epicardial (outer) muscle has counterclockwise apex and clockwise base rotation, while endocardial (inner) muscle has clockwise apex and counterclockwise base rotation to reflect these reciprocal actions in each helical arm. The right image shows the suggested inner and outer cones occupied by the inner and outer helix. The lower images are anatomic: torsion develops ‘between helices’ as the entire inner descending helix rotates clockwise, and entire outer ascending helix rotates counterclockwise. Reproduced form the reference [8] with Publisher’s permission.

Figure 12

Helical fiber orientation (yellow arrows) in normal ventricle (above) with reciprocal 60° angulation and a conical shape. Spherical heart (below) shows a more transverse pattern with 45° or less angulation, mirroring the failing dilated heart. Reproduced form the reference [56] with Publisher’s permission.

Figure 13

(a) Pre wall ejection motion from velocity vector imaging (VVI) is correlated with cardiac anatomy. The upper septum bulges into the right ventricle (upper right); (b) The helical architecture demonstrates absence of helical overlap in region beneath the aortic valve. Its endocardium is formed by the outer, ascending left handed helical arm that does not contract during this interval. Reproduced form the reference [8] with Publisher’s permission.

Figure 14

Right ventricular fiber pattern and HVMB, where the circumferential wrap or basal loop causes compression and narrowing, and the underlying helix with oblique fibers at 60° angles causes shortening and lengthening. Reproduced form the reference [8] with Publisher’s permission.

Figure 15

Figure 1 anatomy modification with “simulated left anterior descending artery” that is a vascular highway that bisects the helix, which constructs the septum and the LV free wall. Anatomy (above), and how (below) LV free wall is on vessel’s left side, and septum (which is three-dimensionally deeper) is on right side.