Rewind the heart: a novel technique to reset heart fibers' orientation in surgery for ischemic cardiomyopathy.
Ischemic cardiomyopathy is the most common cause of dilated cardiomyopathy and congestive heart failure. It affects approximately 1 out of 100 people, most often middle-aged to elderly men. Left ventricular restoration surgery is a challenging therapeutic approach to this pathology: it aims to rebuild a near-normal ventricular chamber in a heart damaged by a myocardial infarction, reducing its volume and improving the fraction of blood ejected by each systole. This is obtained by eliminating the akinetic/dyskinetic part of the cardiac muscle and closing the final defect with or without a synthetic patch. Optimization of surgical repair is mandatory as far as ischemic cardiomyopathy is a worldwide disease responsible for many cardiac deaths and because of its potential use as an alternative to heart transplantation in selected patients. Until now, this surgery has been performed without caring for myocardial fibers' disposition but recent evidences clarified the key role of fibers' alignment in heart physiology. The myocardium of the left ventricle has a unique three-dimensional, multilayered structure: it constitutes the anatomical basis for the cardiac function and for left ventricular torsion, a key movement of normal heart. Myocardial infarction alters myocardial structure in the site of the necrosis and subsequent cardiomyopathy eliminates left ventricular torsion. On the other hand, histological evidences show that myofibers' orientation in the thickness of residual normal myocardium is not changed and that transmural courses of fiber orientation angles near infarct zones were similar to those of normal myocardium. We hypothesize that, with a particular surgical technique, it could be possible to realign the anatomically normal fibers of the residual myocardium in order to rebuild a physiologic setting. We planned a novel surgical technique of left ventricular restoration using a very narrow, string-shaped patch and a particular suturing sequence and technique, whose aim is to near normally oriented residual myocardial fibers. The renewal of left ventricular torsion was evident at sight just at the end of this kind of ventricular restoration, still in the operating room, then confirmed by 2D speckle tracking echocardiography. These observations are indirect proofs of fibers' realignment, as the torsion movement of the left ventricle is due to the interlaced, oblique orientation of myocardial fibers. We herein propose a theoretical explanation of this outcome, drawing a geometrical modeling of the surgical procedure.
Cirillo
Marco
M
Cardiovascular Department, Heart Surgery Unit, Poliambulanza Foundation Hospital, Brescia, Italy. mkyr@libero.it
Arpesella
Giorgio
G
D002309:Cardiology / Q000379:methods; D009202:Cardiomyopathies / Q000601:surgery* / Q000628:therapy*; D004452:Echocardiography / Q000379:methods; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008953:Models, Anatomic; D008954:Models, Biological; D008962:Models, Theoretical; D017202:Myocardial Ischemia / Q000473:pathology*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D013514:Surgical Procedures, Operative; D013903:Thoracic Surgery / Q000379:methods*; D020257:Ventricular Remodeling