he early diastolic velocity of the mitral annulus (Ea) obtained by tissue Doppler imaging (TDI) has been shown to be a preload-independent index for evaluating left ventricular (LV) diastolic function in patients with heart disease. 1,2 When TDI is combined with pulsedDoppler transmitral flow in early diastole (E), the resultant E/Ea ratio has correlated with LV filling pressures measured invasively. [2][3][4][5][6] Several researchers have assessed the lateral mitral annulus, 2,4,6 stating that lateral annular velocities were slightly higher than septal annular velocities and were often easier to quantify, 2 whereas other researchers have successfully used the septal mitral annulus. 3 It is known that cardiac surgery reflects the LV diastolic property and that LV diastolic function after cardiac surgery is 1 of the predictors of the long-term prognosis of patients undergoing cardiac surgery. 7 Although mitral annular velocities are widely used for evaluating LV diastolic function, it is unknown whether the lateral or septal mitral annular velocity more faithfully predicts LV filling pressures after cardiac surgery. We hypothesized that cardiac surgery affects the predictive values for LV filling pressures by measuring mitral annular velocity. The aims of this study were (1) to critically evaluate the usefulness and limitations of TDI for the evaluation of diastolic filling in patients undergoing cardiac surgery and (2) to compare the TDI results of the lateral and septal mitral annulus for the assessment of LV filling pressures, both before and after surgery.
Methods
Study PopulationWe studied 52 consecutive patients undergoing cardiac surgery. All patients were in sinus rhythm and had a normal PQ interval on ECG. Exclusion criteria were atrial fibrillation, paced rhythm, mitral stenosis, severe mitral or aortic regurgitation, acute myocardial infarction, or previous cardiac surgery. All patients underwent transthoracic echocardiography and right-sided cardiac catheterization both before and after surgery. None of the patients showed abnormalities on ECG or cardiac enzyme elevation during the perioperative period. The institutional review boards of Yamaguchi University Hospital approved the investigational protocol, and all patients gave written informed consent before participation.
EchocardiographyAll patients were examined by transthoracic echocardio- Background Although previous investigators reported that mitral annular velocity predicts mean pulmonary capillary wedge pressure (PCWP), it is unknown whether the lateral or septal mitral annular velocity more faithfully predicts PCWP after cardiac surgery.
Methods and ResultsTo assess the effect of cardiac surgery on the predictive values for PCWP by measuring mitral annular velocity, 52 consecutive patients undergoing cardiac surgery were studied. All patients underwent transthoracic echocardiography and right-sided cardiac catheterization both before and after surgery. The peak early diastolic velocity of transmitral flow (E) was measured by pulsed-wave D...
To investigate Ca2+ handling in compensated hypertrophied cardiomyocytes, we measured Ca2+ transients and contraction of hypertrophied rat left ventricular myocytes induced by aortic constriction (AC). The fluorescence ratio (I405/I480) after indo-1/AM loading and circumferential length were simultaneously measured in isolated myocytes. The amplitude of Ca2+ transients (Ca-Amp) was higher in rats with AC than in sham-operated rats (Sham) (0.25 +/- 0.08 vs 0.17 +/- 0.05). There was a positive correlation between Ca-Amp and fractional shortening (FS) in both AC and Sham rats, whereas the ratio of FS/Ca-Amp was smaller in AC rats. These observations suggest that compensated hypertrophied cardiomyocytes exhibit an adaptive increase in Ca-Amp, associated with reduced myofilament responsiveness to an increase in Ca2+. Isoproterenol and forskolin increased Ca-Amp and FS, and decreased time to 50% decline of Ca2+ transients. Although myocytes from AC rats exhibited reduced responsiveness to isoproterenol, responses to forskolin did not differ between the 2 groups. The reduced beta-adrenergic response in Ca2+ handling was probably due to altered beta-adrenoceptor numbers, G-protein function and/or their coupling process.
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