 |
|
|
|
|
|
|
|
This is a brief summary of the implications of the understanding of the myocardial band. Added to this website are the three clips from the Helical Heart DVD, and images of the dissected band with and without legends. The descriptions added here are from the text of Clemente, which will come out at the end of the year, and is the classical atlas for anatomy. Moore and Dalley, and their text will be out in the spring. This is the paramount written text in the US, going to >90% of all students of medicine as the standard text. The myocardial band will create a revolution in thinking about cardiovascular structure and function, and likely will rival the work of William Harvey in 1638. This model of cardiac structure will indicate why the heart fills by suction, via a muscular mechanism: this finding contrasts with conventional teaching describing recoil of the heart, via collagen or potential energy that is stored as the cause. This muscular concept will explain diastolic dysfunction, a cause of heart failure without ventricular dilation, and thus opens the doors for vast new pharmacological treatments of this muscular mechanism. Up to 30% of heart failure patients (among 5,000,000 with CHF.....) fall into this category. Loss of this conical normal spiral configuration is the cause of heart failure, as the normally elliptical ventricle (shaped like a football) stretches and dilates to become circular, like a basketball. Novel and recent treatments have been used to treat the heart by restoring the normal size and shape in a spectrum of diseases like ischemia (after a heart attack), valvular (from mitral or aortic insufficiency of the respective heart valves), and in non-ischemia (primary caused by disease within the heart muscle, independent of ischemia or valve disease) where the most severely damaged area is determined pre operatively, and excluded by a restoration procedure. Heart failure affects 5,000,000 patients in the US and a similar number world wide. 70% have dilated hearts, and many can be treated by restoring geometry towards normal. The dilemma during cardiac pacing is called "non sequential or non uniform contraction", and occurs directly after pacing the heart with an electrode, or by exciting both the atrium and ventricle by wires, which results in non uniformity of the sequential contractions. Novel studies have found ways to isolate the correct pacing site within the heart, and then introduce a pacer that is different from mechanisms now available. This action restores a normal sequential contraction. This development may be used by the entire pacemaker population, if further testing validates its results. New studies in right heart failure have been done. They show a clear reason for right heart failure that relates to septal contraction. As a result, new treatments have been developed to correct this evolved cause of right heart failure. This therapy may be used in patients with pulmonary valve insufficiency, postoperatively, and with structural abnormalities of the RV free wall. The understanding of the embryology of heart development may be improved, and this structural solution may further our understanding of the causes of congenital abnormalities. Editorial Comments from: Gerald D. Buckberg, M.D. |