ECHO parameters of diastolic dysfunction

Abstract

Most patients with cardiac disease have diastolic dysfunction which is characterized by impaired diastolic filling and/or abnormal diastolic relaxation. The trans-esophageal echocardiography (TEE) used routinely during open-heart surgical procedures has exceptional resolution that may permit the identification and grading of diastolic dysfunction. The goal of this study was to determine which echocardiography (ECHO) parameters can best describe diastolic dysfunction due to myocardial remodeling and fibrosis. Baseline transthoracic ECHO was performed on 3-month-old C57BL/6J female mice followed by administration of isoproterenol (2 microg/g/d) for 6 days. On day 7, transthoracic ECHO was performed to determine the change of left ventricular (LV) inflow parameters due to isoproterenol-mediated cardiac remodeling. The mid-LV region was stained with picrosirius red to quantify myocardial fibrosis and demonstrated a 5-fold increase in cardiac fibrosis (p = 0.002). LV mass was increased by 36% (p = 0.0016). Mitral valve flow Doppler peak velocities E and A were measured from a 4-chamber view. The E/A ratio did not change, but the E deceleration time, velocity time integral of the E-A complex (E-A VTI), E/E-A VTI ratio, isovolumic relaxation time (IVRT), and diastolic time all significantly increased. The corresponding tissue Doppler parameter, Ea/Aa ratio, decreased by 25% (p = 0.035). The left atrial dimension and the ECHO index of left atrial pressure (E/Ea) significantly increased (p < 0.02). These data suggest that, with a long-axis and a 4-chamber view, the clinician can adequately determine diastolic function in the open-heart surgical patient.

The Role of 1.5 Tesla MRI and Anesthetic Regimen Concerning Cardiac Analysis in Mice with Cardiomyopathy

“…Furthermore we found, that MMF has a distinct impact on the variability of heart rate-dependent values. In contrary, higher concentrations of isoflurane than commonly used [10], [11], [17] proved to have a beneficial effect on heart rate variability.…”

“…In small animal echocardiography, multiple cycle measurements are commonly used to calculate an average value for LVEF in order to reduce variability of the results [10]. In most MRI studies however, cine imaging results in the calculation of only one single LVEF value [22]–[24].…”

“…As demonstrated above, calculation of an average LVEF as known from small animal echocardiography [10] could reduce the scattering of the values gained from 1.5 T MRI devices. Thereby, a relative reduction of standard deviation of up to 38–45% could be achieved.…”

“…Parasternal long-axis M-mode was used to standardize transducer positioning for short-axis M-mode imaging. For evaluation of cardiac function, 3 consecutive cycles were measured and averaged as described previously [10], [18]. Left ventricular end diastolic (EDV) and systolic (ESV) volumes were calculated using the formulae 7*LVID;d 3 /(2.4+LVID;d) and 7*LVID;s 3 /(2.4+LVID;s).…”

“…Since left ventricular ejection fraction (LVEF) strongly predicts cardiovascular morbidity and mortality, it is often used for monitoring therapeutic success [5]–[8]. Several techniques, such as pressure-volume loops [9], echocardiography [10] or dedicated small animal MRI scanners [11] have been implemented for evaluation of left ventricular function in mice. However, 1.5 Tesla MRI scanners have not been used routinely for cardiac function monitoring in murine models of dilative cardiomyopathy (DCM) so far.…”