Abstract
Introduction: Left ventricular (LV) rate of pressure rise (LV Delta P/Delta t) derived from the continuous Doppler profile of mitral regurgitant jet has been proven to be a reliable [1] and reproducible [2] index of peroperative LV performance in the presence of mild to moderate chronic mitral regurgitation (MR). This study was designed to precise the accuracy of the method in presence of unstable acute MR. Methods: The study conformed to the guiding principles of the AHA guidelines for animal research. Ten pigs (25-30 kg) were anesthetized, intubated and ventilated. Monitoring included left atrial pressure (LAP) line, LV micromanometer-tipped catheter and epicardial echocardiography. MR were created by repetitive echo-guided sections of mitral chordae tendinae by use of endoscopic scissors inserted through LV apex. Data were collected after induction of anesthesia (T0) and at three successive grades of MR (T1-3). MR were quantificated by the mitral to aortic velocity-time integral ratio (VTImit/VTIao) [3]. Doppler derived LV Delta P/Delta t (Dop LV Delta P/Delta t) was calculated according to Bargiggia et al. [4], and peak LV Delta P/Delta t was derived from LV catheterism data. All measurements were made blindly off-line and averaged from three successive cardiac cycles. In order to avoid interference with Dop LV Delta P/Delta t calculation caused by MR-related elevated LAP, data characterized by LAP > 20 mmHg were rejected. Values are expressed as mean +/- SD. Results: Data are summarized in Table 1.Table 1Discussion: These data seems to validate Dop LV Delta P/Delta t measurements in the setting of unstable acute MR. The accuracy of the method was not affected by acute increase of MR in a range of VTImit/VTIao values from 0.98 +/- 0.1 to 1.09 +/- 0.04 and in presence of LAP not exceeding 20 mmHg.
Published Version
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