The helical ventricular myocardial band (HVMB) of Torrent-Guasp, bringing a new light on perennial problem of global, macroscopic, three-dimensional functional architecture of the ventricular myocardium, emerged in early 1970s.

Not perchance, the earliest recognitions came from outside of Spain.

Professor Sir Donald N. Ross, the close friend and the great admirer of Torrent-Guasp’s work, invited him to Guy's Hospital, London, to expose the HVMB concept, which Jane Somerville subsequently compared to Leonardo Da Vinci’s masterpiece.

Some years later, in Geneva, Torrent-Guasp was awarded the Miguel Servetus Prize, signed by Nobelist, Sir Ernst B. Chain.

Since that time, the original HVMB concept has considerably evolved, not only as a result of dedicated work of its creator and his associates, but also because of fascinating advances in experimental and imaging technology, supported by powerful computing hardware and algorithms.

HVMB Anatomy

Here you may find two review papers describing current knowledge of HVMB anatomy:

Kocica MJ, Corno AF, Carreras-Costa F, Ballester-Rodes M, Moghbel MC, Cueva CNC, Lackovic V, Kanjuh VI, Torrent-Guasp F.
The helical ventricular myocardial band: Global, three dimensional functional architecture of the ventricular myocardium.
Eur J Cardiothorac Surg 2006;29(S1):S21-S40.
EJCTS Suppl: Rethinking the cardiac helix: a structure-function journey.
TOP25 articles: European Journal of Cardio-Thoracic Surgery (April - June 2006)
Journal impact factor: 1.616 (2004)

 

Torrent-Guasp F, Kocica MJ, Corno AF, Komeda M, Carreras-Costa F, Flotats A, Cosin-Aguillar J, Wen H.
Towards new understanding of the heart structure and function.
Eur J Cardiothorac Surg 2005;27(2):191-201.
TOP25 articles: European Journal of Cardio-Thoracic Surgery (January - December 2005)
Journal impact factor: 1.616 (2004)

HVMB Dissection Technique

Preparations

Figures 1-20 are depicting preparation phases for Torrent-Guasp's anatomical dissection of the HVMB.

The hearts are prepared by simple boiling in water (without any additive), in order to loosen the connective tissue. The period of boiling was judged empirically, on the appearance of fibers and depended on the size of the specimen - about 10 minutes or less for a hen heart and up to 2 hours for an adult bovine heart. After boiling and subsequent cooling (several hours in refrigerator at 4C), the atria could be easily removed from the heart. Pulmonary artery and aorta are trimmed, leaving proximal 2-3cm. The fat from the atrio-ventricular grooves was removed and all visible, superficial coronary vessels excised.
Dissection of the myocardial mass is undertaken with non-toothed forceps, scalpel and scissors. Blunt dissection by fingers is generally the most satisfactory way of identifying the direction of the linear (fiber) and laminar (layer) pathways. Gentle longitudinal traction was enough to separate long strips of myocardium, whereas forcible lateral traction tended to tear the muscle fiber.

Dissection technique

Figures 21-53 are depicting successive steps of Torrent-Guasp's dissection technique applied for unraveling the ventricular mass into the HVMB.
 

After the separation of the pulmonary artery and the aorta, some superficial fibers (i.e. aberrant fibers) bridging the anterior interventricular sulcus are incised in order to move aside the right ventricular (RV) free wall. By doing so, we arrive to the posterior linear border of the RV cavity, which is represented by the linear bottom of the dihedral angle constituted by the RV free wall and the interventricular septum. The posterior linear border of the RV cavity has special importance, since it points out the only possible trajectory, which would allow further dissection of the HVMB. The beginning of this trajectory is exposed by pushing laterally RV free wall. Following the predominant fiber direction, we can easily see that this path encircles the LV, up to the root of the aorta.
By cutting their anchorage with the left fibrous trigone, we have finished the dissection of the HVMB basal loop. At this point, it is important to notice that some fibers (i.e. belonging to the descendent segment) are sinking into the LV, making the central fold of the HVMB. Trajectory of these fibers, while coming down towards the LV posterior wall, is pointing out an important cleavage plan at level of the interventricular septum. Namely, at the septal level, these fibers are crossing the ascendant segment fibers in a 90-degree angle. At this point, we are able to see this septal crossing from the LV side.
To continue with dissection, we should come back, to the site of the previous posterior linear border of the RV cavity. By pure inspection from the RV side, we can clearly distinguish two muscular strata. The deeper belongs to previously described descendent segment and the more superficial belongs to the ascendant segment. A right-angle crossing of these fibers, as described before, is now also visible from the RV side. The cleavage plan between these two strata, is the same one we described above, entering it from the LV side. The top of the line (i.e. previous posterior linear border of the RV), defined by these two strata, ends on the aortic root at the point of it’s attachment to the right fibrous trigone. To separate described strata, going in between the vertical (more superficial, ascendant segment) and the horizontal (deeper, descendent segment) fibers, the first thing that we should do is to cut-off their anchorage to the right fibrous trigone. Now we are able to proceed with the most delicate part of the dissection, denominated as “dismounting of the aorta”.
Prior to any further description of the dissection method, it is important to emphasize one fact. The only firm aortic attachments to the LV are the fibrous trigones, upon which the aorta leans over the LV outflow tract. Apart from that, the aortic annulus, belonging to the right coronary cusp, provides the additional, weak anchorage of the aorta to the septal portion of the LV. Thus, by cutting-off these firm and weak attachments, it becomes possible to dismount the aorta from the LV. By doing so, we are able to join two parts of the septal cleavage plan. In this manner, progressing along the predominant fiber path, we are able to detach the aorta with fibers belonging to the ascendant segment from the rest of the LV mass. Following the same cleavage plan along the predominant helical fiber path, we are entering the LV cavity, with fingertips appearing behind the anterior papillary muscle, at the level of previously mentioned central fold of the HVMB. If we proceed until we become able to close the fist, our fingertips would appear between anterior and posterior papillary muscle, the former being completely encircled by the hand.
Finally, we came to the most exciting part of the dissection, when the HVMB is ready to be stretched-out. Simple 90-degree rotation around the apex unravels the apical loop segments. Additional 180-degree rotation around the central fold unravels the basal and the apical loops of the HVMB. The HVMB of Torrent-Guasp now appears in its full extent and beauty, with pulmonary artery at one and the aorta at the opposite side.
The elegance and astounding simplicity of this dissection is reflected in the capacity to easily reverse these unraveling steps, with ready re-establishment of the well-known three-dimensional ventricular architecture that existed prior to beginning of dissection.

Segmental anatomy of the HVMB

Figure 54 emphasizes four crucial dissection phases and segmental anatomy of Torrent-Guasp's HVMB.
 

The HVMB is divided in two loops, each of them comprising of two segments. The central 180-degree fold of the HVMB defines two loops: the basal loop (from the root of the pulmonary artery to the beginning of the central fold - i.e. to the anterior papillary muscle) and the apical loop (from the beginning of the central fold to the root of the aorta). Each of these two loops could be further divided in two segments.
The posterior interventricular sulcus, which coincides topographically with the posterior linear border of the RV cavity, divides the basal loop into two segments: the right segment - coinciding with the RV free wall; and the left segment - coinciding with the LV free wall. It is interesting to notice here, that the right segment also defines the outer (non-septal) border of the tricuspid orifice and the left segment defines the outer (non-septal) border of the mitral orifice. These borders are common targets in AV surgical annuloplastic procedures.
The apical loop could be also divided in two segments. After the 180-degree twist (at the central fold of the HVMB), fibers of the descendant segment, make a 90-degree turn around the apex, continuing the fibers of the ascendant segment. Posterior papillary muscle (belonging to the descendant segment), demarcates the border between the descendent and the ascendant segments of the HVMB apical loop.

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