Left ventricular filling dynamics: influence of left ventricular relaxation and left atrial pressure.

Abstract

Peak rapid filling rate (PRFR) is often used clinically as an index of left ventricular relaxation, i.e., of early diastolic function. This study tests the hypothesis that early filling rate is a function of the atrioventricular pressure difference and hence is influenced by the left atrial pressure as well as by the rate of left ventricular relaxation. As indexes, we chose the left atrial pressure at the atrioventricular pressure crossover (PCO), and the time constant (T) of an assumed exponential decline in left ventricular pressure. We accurately determined the magnitude and timing of filling parameters in conscious dogs by direct measurement of phasic mitral flow (electromagnetically) and high-fidelity chamber pressures. To obtain a diverse hemodynamic data base, loading conditions were changed by infusions of volume and angiotensin LI. The latter was administered to produce a change in left ventricular pressure of less than 35% (A-1) or a change in peak left ventricular pressure of greater than 35% (A-2). PRFR increased with volume loading, was unchanged with A-1, and was decreased with A-2; T and PCO increased in all three groups (p < .005 for all changes). PRFR correlated strongly with the diastolic atrioventricular pressure difference at the time of PRFR (r = .899, p < .001) and weakly with both T (r = .369, p < .01) and PCO (r = .601, p < .001). The correlation improved significantly when T and PCO were both included in the multivariate regression (r = .797, p < .0001). PRFR is thus determined by both the left atrial pressure and the left ventricular relaxation rate and should be used with caution as an index of left ventricular diastolic function.Circulation 74, No. 1, 187-196, 1986. RELAXATION ABNORMALITIES are one of the earliest manifestations of cardiac dysfunction and frequently precede systolic dysfunction in many disease states.'' Early filling function has been evaluated in a variety of diseases, e.g., coronary artery disease, hypertrophic cardiomyopathy, hypertensive heart disease, aortic valve disease, and congestive cardiomyop-

Echo‐Doppler left ventricular filling abnormalities in patients with rheumatoid arthritis without clinically evident cardiovascular disease

“…Many factors can affect mitral flow velocity measurements [26][27][28]. For this reason, we applied a strict selection process for both patients and matched controls.…”

Long‐term prognostic value of an index of myocardial performance in patients with myocardial infarction

“…26 Isovolumetric contraction time is included in the numerator of the Tei formula and is an important component of pre-ejection period, correlating inversely with +dP/dT. 27 Isovolumetric relaxation time, another component of the Tei formula included in the numerator, corresponds to the time constant of LV relaxation (tau), 28 which is significantly longer in patients with previous MI. 29 The value of tau increases through all stages of diastolic dysfunction, 30 so that isovolumetric relaxation time becomes prolonged with abnormal relaxation in most patients with coronary artery disease.…”

Diastolic Filling and Pressure Imaging: Taking Advantage of the Information in a Colour M-mode Doppler Image

“…A multitude of indices such as peak E and A velocity, their ratio, and acceleration and deceleration times are derived from this velocity pattern and proposed as markers for diastolic function [1][2][3][4][5] . Intensive research, using numerical [6][7][8][9] and in vitro [10] models, next to observations in animals and humans [8,[11][12][13][14][15][16] , have clearly elucidated the physical and physiological determinants of the transmitral velocity pattern. Although it provided us with many clinical useful insights, this research revealed also the limitations of pulsed wave Doppler echocardiography in clinical practice for assessing diastolic function.…”