A Noninvasive Method for Assessing Impaired Diastolic Suction in Patients With Dilated Cardiomyopathy

Abstract

Background— Diastolic suction is a major determinant of early left ventricular filling in animal experiments. However, suction remains incompletely characterized in the clinical setting. Methods and Results— First, we validated a method for measuring the spatio-temporal distributions of diastolic intraventricular pressure gradients and differences (DIVPDs) by digital processing color Doppler M-mode recordings. In 4 pigs, the error of peak DIVPD was 0.0±0.2 mm Hg (intraclass correlation coefficient, 0.95) compared with micromanometry. Forty patients with dilated cardiomyopathy (DCM) and 20 healthy volunteers were studied at baseline and during dobutamine infusion. A positive DIVPD (toward the apex) originated during isovolumic relaxation, reaching its peak shortly after mitral valve opening. Peak DIVPD was less than half in patients with DCM than in control subjects (1.2±0.6 versus 2.5±0.8 mm Hg, P <0.001). Dobutamine increased DIVPD in control subjects by 44% ( P <0.001) but only by 23% in patients with DCM ( P =NS). DIVPDs were the consequence of 2 opposite forces: a driving force caused by local acceleration, and a reversed (opposed to filling) convective force that lowered the total DIVPD by more than one third. In turn, local acceleration correlated with E-wave velocity and ejection fraction, whereas convective deceleration correlated with E-wave velocity and ventriculo:annular disproportion. Convective deceleration was highest among patients showing a restrictive filling pattern. Conclusions— Patients with DCM show an abnormally low diastolic suction and a blunted capacity to recruit suction with stress. By raising the ventriculo:annular disproportion, chamber remodeling proportionally increases convective deceleration and adversely affects left ventricular filling. These previously unreported mechanisms of diastolic dysfunction can be studied by using Doppler echocardiography.

Acute Left Ventricular Dynamic Effects of Primary Percutaneous Coronary Intervention

“…This stored potential energy is then converted to kinetic energy during isovolumetric relaxation. This kinetic energy allows for rapid reconfiguration of the LV back to its pre-ejection state, which creates a rapid decline in LV pressure (24). Although we could not document an improvement in the active relaxation time constant Tau during the acute phase, an improved systolic apical function may account for the improved diastolic function in the longer term.…”

Assessment of Left Ventricular Function by Cardiac Ultrasound

“…This noninvasive approach has been validated in animals (109) and in patients with hypertrophic cardiomyopathy, demonstrating a significant improvement in diastolic suction with successful alcohol septal ablation (110). Intraventricular pressure difference has been shown to be low in patients with dilated cardiomyopathy (111), whereas the augmentation of suction has also proven highly predictive of exercise capacity in normal subjects and heart failure patients (112). As noted in the preceding text, intraventricular pressure difference measurements along the LVOT have been shown to estimate systolic function accurately.…”

Loss of Adrenergic Augmentation of Diastolic Intra-LV Pressure Difference in Patients With Diastolic Dysfunction

“…This IVPD rapidly accelerates blood into the LV in early diastole (1). In response to adrenergic stimulation, as occurs during exercise, the early diastolic IVPD normally increases due to a See page 871 decrease in minimum LV pressure, allowing for more rapid filling without an abnormal increase in LA pressure (2)(3)(4). This larger IVPD results from both ejection to lower end-systolic volume and more rapid LV relaxation.…”

“…Patients with heart failure (HF) and reduced ejection fraction (EF) have a reduced response to adrenergic stimulation due to down-regulation and uncoupling of beta receptors (5)(6)(7). As a result, in HF with reduced EF, the decrease of early diastolic LV pressure in response to adrenergic stimulation is reduced (2,8,9). Thus, the exercise-induced increased early diastolic filling rate in patients with reduced EF is dependent upon an increase in LA pressure (9).…”