Left ventricle diastolic dysfunction and prognosis.

Normal LV diastolic function requires integration of left ventricular ejection, relaxation, and structure and is an active energy-requiring process.1 For example, LV diastolic function becomes markedly abnormal immediately following coronary ligation, before detectable changes in other measures of cardiac function, including wall motion or electrocardiographic S-T segment shifts.2 LV diastolic function is impaired by all of the common pathological processes that affect LV function or produce LV hypertrophy or fibrosis, including hypertension, diabetes mellitus, ischemia, myocarditis, toxins, and infiltrative cardiomyopathies. Thus, LV diastolic performance is a sensitive indicator of cardiovascular dysfunction. Systolic function is conveniently (although not always accurately) measured as the ejection fraction. Diastolic function has been more difficult to evaluate.1,3 Traditionally, invasive measures of LV diastolic pressure–volume relations and the rate of LV pressure fall during isovolumetric relaxation have been used. However, these methods are not practical for routine clinical use and do not adequately evaluate all aspects of diastolic filling.3 Approximately 3 decades ago, pulsed spectral Doppler was first used to quantitatively assess the velocity of blood flow from the left atrium into the LV. Since then, there have been many advances in the noninvasive assessment of LV diastolic function by echo-Doppler. One of the most important of these advances was the development of tissue Doppler imaging, which was accomplished by adjusting the Doppler filter settings to focus on the low-velocity, high-amplitude signals produced by tissue motion. Ironically, these had previously been actively filtered out as ‘wall clutter’ and thereby overlooked. Tissue Doppler imaging can measure the rate of mitral annular motion. The early diastolic annular velocity away from the apex is reduced and delayed in the presence of impaired relaxation. Tissue Doppler imaging can also be used to assess LV myocardial strain. Other more recent advances include color M-mode Doppler to measure flow propagation into the LV, and speckle tracking to assess twisting of the LV apex relative to the mitral annulus and untwisting in early diastole. Comprehensive echocardiographic evaluation of the dynamics of LV filling uses Doppler measurements of mitral inflow and pulmonary venous flow, along with tissue Doppler evaluation of the early diastolic mitral annular velocities and measurements of left atrial size.4 By combining these data with the use of written algorithms, specific patterns of LV filling can be discerned.4 These patterns can define both normal diastolic function and the stages of diastolic dysfunction. Echo-Doppler evaluation of diastolic function provides important prognostic information in a wide variety of patients. A normal filling pattern in community-dwelling subjects indicates an excellent prognosis.1 In contrast, an abnormal filling pattern and progressively greater abnormalities of left filling (impaired relaxation versus pseudonormalized and restricted filling patterns) indicate patients with a progressively increased risk of subsequent mortality. The stage of diastolic dysfunction correlates with the impairment of exercise capacity in patients without myocardial ischemia better than resting left ventricular ejection fraction (LVEF).5 In patients with heart failure, the stage of diastolic dysfunction is a stronger predictor of mortality than ejection fraction.1 A shortened early deceleration time indicates an increased LV operating stiffness. It is a hallmark of restrictive filling pattern and denotes poor prognosis in patients with myocardial infarction, dilated cardiomyopathy, heart transplantation, hypertrophic cardiomyopathy, and restrictive cardiomyopathy.4 Both pseudonormalized and restricted filling patterns indicate a 4-fold increase in the risk of death in patients with heart failure and coronary artery disease.6 Similarly, an increased ratio of early mitral flow/early annulus velocity indicates poor prognosis in a variety of patients.4 Recently, Mogelvang et al7 found that early diastolic annular velocity predicted mortality in a general population of patients, most of whom were free of apparent systolic and diastolic dysfunction by conventional echocardiographic methods. However, there have been few data examining the utility of serial echo-Doppler assessments of LV filling, particularly in patients without significant systolic dysfunction. Kane et al8 recently reported on a randomly selected community cohort during 4 years of follow-up. They found that grade of systolic dysfunction worsened in 23% of subjects and was associated with older age. During 6.3 years of additional follow-up, The opinions expressed in this article are not necessarily those of the editors or of the American Heart Association. From the Cardiology Section, Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC. Correspondence to Dalane W. Kitzman, MD, Professor of Internal Medicine: Cardiology and Geriatrics, Wake Forest University School of Medicine, Medical Center Blvd, Winston-Salem, NC 27157-1045. E-mail [email protected] (Circulation. 2012;125:743-745.) © 2012 American Heart Association, Inc.