New Untwist on Diastole

Diastolic dysfunction contributes significantly to the clinical syndrome of congestive heart failure in the settings of both preserved and impaired left ventricular (LV) systolic function.1,2 Over the past 20 years, the clinical diagnosis of diastolic dysfunction has been based largely on echocardiographic Doppler parameters of LV filling.3 The most important limitation of these parameters is their dependence on loading conditions. New practical and comprehensive methods of evaluating diastolic function are critically needed not only for diagnosis but also for testing emerging new therapies.Article p 2524 Recent work has elucidated both intracellular and extracellular mechanisms that contribute to diastolic dysfunction, and some progress has been made in finding new treatments for diastolic heart failure. Additional research has evaluated the contribution of LV architecture and its role in maintaining the normal contraction sequence that optimizes mechanical efficiency. The importance of systolic twist and the subsequent recoil that leads to diastolic untwisting was examined in the article by Notomi et al4 using tissue Doppler techniques in both normal subjects and patients with hypertrophic cardiomyopathy, at rest and during exercise.Leonardo DaVinci5 in the 16th century and Rushmore6 in the 1950s described the rotational motion of the left ventricle.7 In 1970, McDonald7 reported a study in which he placed radiopaque markers on the epicardium of patients undergoing closed mitral valvuloplasty. He demonstrated that the pre-ejection phase was characterized by descent of the base and a counterclockwise rotation of the epicardial surface of the left ventricle with a thrust of the apex toward the chest wall. In late systole, there was a slight clockwise rotation and apical retraction.Using blunt dissection, Torrent-Guasp et al8 demonstrated that the ventricles consist of a single myofiber band starting at the right ventricle just below the pulmonary valve and forming …