{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T06:06:55Z","timestamp":1760249215770},"reference-count":34,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2009,2,4]],"date-time":"2009-02-04T00:00:00Z","timestamp":1233705600000},"content-version":"vor","delay-in-days":4539,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Clinical Cardiology"],"published-print":{"date-parts":[[1996,9]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p><jats:italic>Background:<\/jats:italic> The maximal negative dP\/dt [max (\u2010)dP\/dt] and time constant (T) are useful indices for evaluating left ventricular (LV) relaxation, but they require invasive procedures.<\/jats:p><jats:p><jats:italic>Hypothesis:<\/jats:italic> The purpose of this study was to obtain max (\u2010)dP\/dt and T using the continuous\u2010wave Doppler aortic regurgitation velocity curve (AR\u2010CW) noninvasively. Using the Bernoulli equation, the AR\u2010CW allows accurate determination of the pressure gradients (PG) between the aorta and the left ventricle.<\/jats:p><jats:p><jats:italic>Methods:<\/jats:italic> In 10 patients with trivial to mild AR, the rising segment of the AR\u2010CW reflecting LV pressure decrease was digitized with the cardiac image analysis system. Transpulmonary contrast\u2010enhanced Doppler echocardiography was used in three patients to obtain intense velocity envelope. The PG curve and the first derivative curve were reconstructed and the maximal point of the first derivative curve, which is consistent with max (\u2010)dP\/dt, was termed as maximal rate of pressure fall (maxRPF). As T (calculated according to the method of Weiss) can be obtained from T=Pm\/max (\u2010)dP\/dt [Pm: LV pressure at the phase of max (\u2010)dP\/dt], we calculated T from Pm\/maxRPF (Pm=dicrotic notch pressure \u2010 4Vm<jats:sup>2<\/jats:sup>) (Vm: AR velocity at the phase of maxRPF).<\/jats:p><jats:p><jats:italic>Results:<\/jats:italic> The Doppler\u2010derived maxRPF and T (T<jats:sub>d<\/jats:sub>) approximated the catheter\u2010derived max (\u2010;)dP\/dt and T (y=0.85x+ 245, r=0.97, p&lt;0.001, y=0.79x+4, r=0.87, p&lt;0.001). In addition, dobutamine echocardiography was performed in nine patients showing increased maxRPF and decreased T<jats:sub>d<\/jats:sub>, indicating improvement of LV relaxation.<\/jats:p><jats:p><jats:italic>Conclusion:<\/jats:italic> These Doppler\u2010derived new indices are sufficiently useful to evaluate LV relaxation noninvasively.<\/jats:p>","DOI":"10.1002\/clc.4960190907","type":"journal-article","created":{"date-parts":[[2009,2,4]],"date-time":"2009-02-04T07:42:45Z","timestamp":1233733365000},"page":"709-715","source":"Crossref","is-referenced-by-count":5,"title":["Evaluation of left ventricular relaxation using the continuous\u2010wave doppler velocity profile of aortic regurgitation: Noninvasive measurement of left ventricular negative dP\/dt and time 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