Validation of this helical heart concept — and of the other advances presented in this book — has already been demonstrated. Yet the step of further scientific confirmation remains. This must be done by open-minded members of the medical community. We need them to endorse additional study and testing. This will lead to greater medical refinements of these approaches, and greater acceptance in the community.
The staging for this promising future has already taken place. The only question now is, when will the curtain go up?
Link to video of The Cardiac Dance; Spirals of Life:
www.youtube.com/watch?v=8ksNlYfgeRw
CHAPTER 24
Case of the Missing Link: The Septum
Mysteries abound in medicine. Many persist for centuries, until new discoveries and understandings can reveal the truth.
There is no portion of the heart more enigmatic than the septum.
Figure 1: Typical image of heart, showing the right and left ventricles and septum separating them.
This thick curtain of muscle separates the left and right ventricles. (Figure 1) Yet understanding its function has long remained a puzzle. This is not simply an academic concern. It has real-world consequences for vast numbers of patients. For example, a common occurrence after open-heart surgery is that the septum does not work properly — while the ventricles seem to function just fine. The effects that this abnormality has on the heart are often underestimated. Its occurrence may be life-changing.
We know that disease develops when normal structure is distorted, and that the only valid treatment is to restore normality. Yet a dilemma exists when you don’t understand what is normal. How can effective treatment be provided without this knowledge? This lack in understanding explains why so many treatments are ineffective.
Exploring the riddle of the septum takes us into a shadowy world of unanswered questions.
Clues from the Past
The medical profession has long attempted to understand what the septum does, since this knowledge could improve our ability to care for the heart. The origins of this quest stem back to when Hegar, a renowned anatomist and physician, asserted in 1865 that “Cardiac anatomy and function will be uncertain until the structure and function of the crossed angles of fibers in the septum are defined.” Hegar’s object of wonderment remained a mystery until Paco Torrent-Guasp taught us that these are the oblique (angled) fibers of the helix, and they make up the septum.
Despite this development, the age-old pursuit to understand the septum continues to be impeded by how those in medicine perceive the heart today. They persist in viewing it like a topographical map with three landmarks: the left and right ventricles, and a muscular septum between them. Hegar’s warning was right. We cannot see truth if we’re only fixating on what is easily observable.
But an alternative exists, one that lets us think of structure in a manner that can explain a wide variety of ailments. Our vision expands once we think of the heart’s structure as the helix — as hinted at by Hager one-and-a-half centuries ago. This pathway suddenly carries us to dramatic new discoveries — ones that I will describe for you in this chapter.
As you will read, seemingly diverse issues (including right heart failure, infant cardiac procedures, ventricle assist devices, pacemakers, faulty valves, low blood pressure, and diastolic dysfunction) will encounter new breakthroughs all linked to a novel and comprehensive appreciation of the heart’s structure. This involves developing an even deeper perception of how the helical ventricular myocardial band (comprised of an inner helix containing two arms and an outer surrounding wrap) will determine heart function. (Figure 2)
Figure 2: Displays how a heart’s muscle fibers are oriented. (The top light-colored area is fatty tissue on the heart’s surface that is removed below.) The upper portion shows the surrounding wrap of circumferential muscle (called the basal loop). The septum is formed by the helical fibers displayed in the lower part of the heart’s conical shape, which is made of a helix that has 2 arms of muscle fibers that cross each other at 60° angles (they form the apical loop, with a vortex at its tip or apex).
This is the beauty of Paco’s contribution. His unfolding of the heart to reveal its structure changes everything we think about how form impacts performance. The cardiac world becomes simpler and clearer. Comprehending this normality would permit me to begin untangling the many mysteries brought to light within this chapter.
The Chase Begins
Exploring the secrets of the septum made me feel like I was in a detective story as I tracked down the “bread crumbs” laid out before us.
These clues begin with the heartbeat. Two of the biggest hints are the narrowing and shortening motions of the heart during contraction of the right ventricle. These two movements occur during each of the three billion heartbeats within our lifetime. Yet, the mechanism by which shortening is achieved has largely remained unknown until now.
So far in this book, we have only addressed heart failure in the left ventricle (that fills and then ejects blood to circulate through the body). But failure of the right ventricle (that pumps oxygen-depleted blood to the lungs to be re-oxygenated) has always been a perplexing predicament — especially because of our limited understanding of the mechanical forces that determine the right ventricle’s performance.
The conventional view of right ventricular function insists that the surrounding thin right ventricle (RV) “free wall” (a surrounding wrap that encircles the outer wall of the RV, but not the septum) — compresses the blood in the right ventricular cavity against the thickened flat septum — to cause its ejection into the lungs. The action is similar to how a bellows might be used in a fireplace to compress air forward to feed the flames. This concept is unchanged from William Harvey’s theories in the 1600s.
Further support for the bellows concept of the ventricles came from the more modern use of two-dimensional imaging tools (ventriculogram and echocardiogram) that show this narrowing action. Yet in addition to this compression… these tools also saw a shortening movement of the RV (right ventricle).
But they could not clarify why it shortened, or explain the importance of its shortening.
As we will soon find, the mechanism of shortening relates to the septum. This knowledge will shed light on the true nature of the right ventricle’s function.
Deepening the Pursuit
My thesis, which you’ve heard a million times by now, is that heart anatomy determines its performance. This led to my need to understand structural form, so that the mechanical reasons for the heart’s movements could be established.
This investigation made me feel a little like Sherlock Holmes. I recalled how Holmes would frequently ask Dr. Watson, “How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?”128
Popular medical belief said that right ventricle failure could be explained by the bellows concept. But I knew this theory was not true. Sherlock’s reductio ad absurdum aphorism then leads us to look at the septum as the likely prime suspect in defining right ventricular performance.
“The Game is Afoot”
My quest to verify the role of the septum was successful. New deductions emerged after I used my knowledge of the helical ventricular myocardial band to put missing pieces together. Moreover, reports made by others were used to further build a solid case for understanding the function of the right ventricle.
I embraced the classic detective credo: “The simplest answer is often the correct one.” The helical ventricular myocardial band concept identified that only two component parts make up the right ventricle’s architecture. First, there was the surrounding wrap of the RV free wall, the one upon which nearly everyone had exclusively focused. The second was the helix of the septum. I reasoned that it may provide the simplest explanation for long-sought answers — because, quite simply, it was the only part left.
I believed that deductions could be made about the importance of each
of these two parts (the circumferential wrap and helical septum) — by measuring how the right ventricle’s function was affected — after each of them was injured.
The wrap was the easiest starting place because it is on the heart’s surface. Prior researchers described extremely inventive ways to cause wrap damage: burning it by electrocautery, cutting the wrap completely out and replacing it with a patch that could not contract, or surgically removing it and then sewing it back (it subsequently would be made functionless by inducing electrical fibrillation).129–131 Despite these devastating interventions, the right ventricle always functioned properly! This led to a stunning conclusion: the free wall did not play a significant role in right ventricular performance. No effect followed removal of its bellows action.
The power of the septum had finally captured the spotlight.
Step two was now needed. The septum must be made nonfunctional, while leaving a healthy wrap. The septum was damaged by impairing its nourishment (by closing the right coronary artery) and then either using electrocautery to burn its external surface… or by interrupting its electrical impulses… or by raising resistance in the lung blood vessels (by restricting the outflow of blood from the right ventricle). Each intervention made the right ventricular shape circular, which caused the septum to bulge toward the left ventricle cavity. In every instance, distorting septum architecture caused right heart failure.132
It became clear: the septum was responsible for most right ventricle performance. My realization that damage to the septum causes right ventricular failure led me to appreciate that “the septum is the lion of the right ventricle.”
The Secret of Shortening
The second riddle that needed to be solved was why the right ventricle shortened. There was no medical understanding for why this happened. Yet they did not know what I knew: Paco’s helical heart model shows that contraction of the septum’s helical muscle causes shortening. A valuable clue toward helping us understand the septum’s performance.
This knowledge had not been recognized. Many believed the right ventricle shortens due to contraction of longitudinal (up and down) right ventricle muscles. While it seems natural to think that a longitudinal muscle pulls the base toward the apex (conical tip of the heart) as the heart shortens by 30% — no longitudinal muscle fibers exist in the septum! (The only exception is the thin papillary muscle that holds attachments for the heart valve).
Pursuing the cause behind this mystery motion exposed the weakness of the conventional two-dimensional imaging tools that had been relied upon for so many years. They record motion, but do not explain why it happens. Up-to-date three-dimensional tools reveal it’s the heart’s twisting movement that explains shortening. A coiling motion is generated by reciprocal contraction (rotating in opposite directions) of the helix’s spiral muscles… with the direction of movement guided by that moment’s dominant spiral arm.
Uncovering this connection allowed us to explain how the helical ventricular myocardial band determines right ventricle function. First, the RV outer free wall’s bellows function is less efficient, as its transverse (horizontal) fibers only cause compression — accounting for just 20% of performance. Second, the helical septum produces twisting that generates the powerful RV ejection of blood into the lung. Its oblique (angled) fibers create twisting — a muscular action responsible for 80% of right heart efficiency.133
Key to Overcoming Counterforces
The importance of the septum’s function becomes even clearer as we explore how its vigorous contraction gives the right ventricle its ability to push blood out of the ventricle and past its opposition — the natural “counterforce” of the blood vessels feeding the lungs.
What is this “counterforce?” During normal ejection, the vessels or arteries feeding the lung and the body will offer opposition to the blood flow directed at them from the heart — due to their progressively narrowing diameters. This is called “vessel resistance.” It was known that the amount of such opposition by the vessels to the lungs is lower than that from those going to the rest of the body. In fact, lung vessel resistance is only one-sixth of the whole body vessel resistance — so the heart’s work during right ventricular ejection (when it empties blood into the lungs) is substantially less than that for the left ventricle (which empties into the body).
This low lung vessel resistance means the less-effective wrap, which only causes compression (bellows), can by itself provide adequate RV emptying into the lungs. Septum twisting is not needed under normal conditions. However — disease may increase lung vessel resistance. When that occurs — right ventricular failure (as described later in this chapter) will develop if the septum is unable to twist and provide the added required force.
It’s a straightforward concept that, once understood, brings unprecedented insight for a surprisingly accurate bedside diagnosis… far better than possible by use of the current sophisticated diagnostic equipment. The truth emerges because of a deep understanding of why things happen.
As an example, Saleh Saleh, a colleague of mine, was making clinical rounds with medical students, interns, and residents, when they encountered a patient with extensive coronary artery disease. The patient’s major left and right coronary vessels were completely obstructed. Yet there were no signs of right heart failure — even though lung vascular resistance was high. Saleh told this cadre of students, “At least we know the coronary artery responsible for supplying blood to the septum was normal and without obstruction, since the right heart was functioning well” (given that right heart performance depends on the septum, he realized the septum must be receiving sufficient nourishment to function properly). His astonished listeners were leery that such a conclusion could be made without laboratory testing. But Saleh was confident.
So after rounds, these young doctors hurried to review the patient’s coronary angiogram (pictures of blood flow through the coronary arteries)… and were flabbergasted to confirm the accuracy of Saleh’s bedside assessment. But his decision was not capricious, as he was armed with the most powerful knowledge — an understanding of the helical ventricular myocardial band. He simply knew what to look for, rather than relying only on a test to give the answer.
Saleh is among the few to adopt the helical ventricular myocardial band explanation of heart function. While clues to identifying the septum’s helical configuration exist — the concept is still not widely accepted, and the guidance it can provide toward better treatment is rarely used.
Peril of the Septum: Turning a Football into a Basketball
As I’ve said before, disease reflects a departure from normality, and its successful treatment rebuilds normality. It follows that negative outcomes with patients may be due to the lack of awareness of the heart’s true structure.
Right ventricular failure is a perfect example, since it is difficult to manage, and medical teams consistently try to enhance the RV “bellows effect” to overcome it. They do this by delivering excess fluid into the right ventricle in order to stretch its free wall in an effort to expand the wrap. Yet improvement is either limited, or heart failure worsens.
The problem is the ongoing lapse in recognizing that this RV free wall contraction accounts for only a small percentage (20%) of its function. In reality, the septum is responsible for the majority (80%) of right ventricular function133 — so it must always be the chief suspect behind causing (and then resolving) right ventricular failure.
This brought up a new query, one that had not been tested: Would the septum’s vital role in right ventricular function be hampered if its helix shape was disrupted?
Clues were out there. We knew that left ventricular function crumbles if its elliptical helix shape (football) changes into a basketball-like form. Not surprisingly, my sleuthing revealed that the right ventricle suffers the same fate — including when excess fluids are given to “stretch” the bellows in an attempt to improve right heart failure. The right ventricle’s portion of the septum also becomes stretched an
d its shape distorted into a more spherical form — its helical muscle fibers becoming more horizontal because of this expansion.
Knowing that the elliptical football is better than the spherical basketball shape for the heart, it became apparent to me that the direction of septum stretch did not matter. A circle is a circle. Similar dysfunction occurs when the septum bulges toward either the left or right ventricular chambers (since the septum’s now horizontal helix fiber angles will impair its performance).
This discovery may be initially looked upon as bad news — but there is good news as well, since recognizing these mechanics is the stepping stone to a fresh approach. They tell us that restoring normal septum architecture could be a successful treatment for many different conditions.
Transforming Knowledge of Form and Function into Better Patient Care
Just as the classic detective gathers all of the suspects and clues together to reveal what he has deduced about the case, I will now present a series of real world examples that show how correctly understanding structure reveals remedies that will benefit patients who have right ventricle failure from a variety of different causes. The septum is the one consistent factor in each “mini-story.”
Astounding Dilemma During Open-Heart Surgery: “Sweeping It Under the Rug”
Let me start by saying the mystery surrounding the septum has resulted in a “sweep it under the rug” approach to this injury when it malfunctions.
Solving the Mysteries of Heart Disease Page 43