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Diastolic Time Interval (diastolic + time_interval)
Selected AbstractsCardiac function during mild hypothermia in pigs: increased inotropy at the expense of diastolic dysfunctionACTA PHYSIOLOGICA, Issue 1 2010H. Post Abstract Aim:, The induction of mild hypothermia (MH; 33 °C) has become the guideline therapy to attenuate hypoxic brain injury after out-of-hospital cardiopulmonary resuscitation. While MH exerts a positive inotropic effect in vitro, MH reduces cardiac output in vivo and is thus discussed critically when severe cardiac dysfunction is present in patients. We thus assessed the effect of MH on the function of the normal heart in an in vivo model closely mimicking the clinical setting. Methods:, Ten anaesthetized, female human-sized pigs were acutely catheterized for measurement of pressure,volume loops (conductance catheter), cardiac output (Swan-Ganz catheter) and for vena cava inferior occlusion. Controlled MH (from 37 to 33 °C) was induced by a vena cava inferior cooling catheter. Results:, With MH, heart rate (HR) and whole body oxygen consumption decreased, while lactate levels remained normal. Cardiac output, left ventricular (LV) volumes, peak systolic and end-diastolic pressure and dP/dtmax did not change significantly. Changes in dP/dtmin and the time constant of isovolumetric relaxation demonstrated impaired active relaxation. In addition, MH prolonged the systolic and shortened the diastolic time interval. Pressure,volume analysis revealed increased end-systolic and end-diastolic stiffness, indicating positive inotropy and reduced end-diastolic distensibility. Positive inotropy was preserved during pacing, while LV end-diastolic pressure increased and diastolic filling was substantially impaired due to delayed LV relaxation. Conclusion:, MH negatively affects diastolic function, which, however, is compensated for by decreased spontaneous HR. Positive inotropy and a decrease in whole body oxygen consumption warrant further studies addressing the potential benefit of MH on the acutely failing heart. [source] Modified TEI Index: A Promising Parameter in Essential Hypertension?ECHOCARDIOGRAPHY, Issue 4 2005Nurgül Keser M.D. Purpose: Modified TEI index is pointed to be more effective in the evaluation of global cardiac functions compared to systolic and diastolic measurements alone. We planned to determine its applicability in hypertension and relation with left ventricular mass index (LVMI). Methods: We studied 48 patients with mild/moderate hypertension and normal coronary angiograms. In total 22 patients (12 men, 10 women, mean age: 55 ± 6) with normal LVMI were studied in group I, 26 patients (12 men, 14 women, mean age: 57 ± 7) with increased LVMI in group II, and 20 patients (10 men, 10 women, mean age: 53 ± 7) with normal blood pressure as a control group. Standard 2D, Doppler, and mitral annulus pulse wave tissue Doppler were used for all measurements. Modified TEI index was calculated as diastolic time interval measured from end of Am wave to origin of Em (a,) minus systolic Sm duration (b,) divided by b(a,,b,/b,). Results: Modified TEI index was significantly higher in both groups than normal group and in group II than in group I. (Control group: 0.33 ± 0.05, group I: 0.51 ± 0.17, group II: 0.68 ± 0.16, P< 0.0001). Conclusion: Modified TEI index, a marker of left ventricular systolic and diastolic functions, is impaired in hypertensives before hypertrophy develops and impairment is more prominent in hypertrophy. Therefore, (1) modified TEI index in hypertensives is a safe, feasible, and sensitive index for evaluation of global ventricular functions. (2) Evaluation of hypertensives with this index periodically may guide interventions directed toward saving systolic and diastolic functions. (3) Modified TEI index is gaining importance as a complementary parameter to standard Doppler or in cases where standard Doppler has its limitations. [source] Estimation of Left Ventricular Filling Pressure by Doppler Echocardiography in Dogs with Pacing-Induced Heart FailureJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 3 2008K.E. Schober Background: Congestive heart failure (CHF) is a common clinical syndrome characterized by elevated filling pressure. Hypothesis: Doppler echocardiographic (DE) variables of left ventricular (LV) filling can predict a decline of LV end-diastolic pressure (LVEDP) induced by acute preload reduction in dogs with compensated CHF. Animals: Five male hound dogs. Methods: Dogs previously instrumented with a transvenous cardiac pacemaker and a LV pressure gauge were paced at 160,180 bpm to induce mild CHF characterized by LVEDP > 20 mmHg. LVEDP and 9 DE variables of LV filling derived from diastolic time intervals, transmitral and pulmonary venous flow, and tissue Doppler imaging were measured simultaneously at baseline and 30, 60, 120, and 240 minutes after furosemide (4 mg/kg, IV) or placebo (0.9% saline, IV). Repeated measures analysis of variance and correlation analysis were used to determine the association between the decline of LVEDP after furosemide and DE measures of LV filling pressure (LVFP). Results: Furosemide but not placebo decreased LVEDP (P < .001). The ratio of early transmitral flow velocity to LV isovolumic relaxation time (E : IVRT) predicted LVEDP best (R2= .50; P < .001). Correlations were also found between LVEDP and IVRT, E, ratio between E and late diastolic transmitral flow velocity (E : A), and early diastolic velocity of the mitral annulus (Ea). The ratio of E to Ea (E : Ea) was not useful in the prediction of LVEDP in this model. Conclusion and Clinical Importance: E : IVRT can be used to predict LVFP in dogs with mild left-sided CHF induced by rapid pacing. [source] Right ventricular myocardial isovolumic relaxation time and pulmonary pressureCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2006Pulsed Doppler tissue imaging in resurrection of Burstin's nomogram Summary Aims:, Non-invasive assessment of pulmonary artery systolic pressure (PASP) has several limitations. As previously described by Burstin, the right ventricular (RV) isovolumic relaxation time (IVRt) is sensitive to changes in PASP. We therefore compared RV myocardial IVRt, derived by Doppler tissue imaging (DTI), with simultaneously measured invasive PASP. Methods and results:, Twenty-six consecutive patients (18 males, mean age 52 ± 12 years, range 23,75) underwent a simultaneous Doppler echocardiography, including DTI, and cardiac catheterization examination for measurement of PASP and right atrial mean pressures. IVRt was measured using the myocardial velocities by pulsed DTI at both basal and mid cavity segments of the RV free wall. As diastolic time intervals are influenced by heart rate IVRt was corrected for heart rate (IVRt/RR%). A significant correlation was found between PASP and regional IVRt/RR% at both the basal (r = 0·42, P<0·05) and mid cavity segment (r = 0·71, P<0·001). Furthermore, when only patients with normal right atrial pressures (<7 mmHg) were taken into account, the correlation coefficient improved at both basal and mid cavity segments (r = 0·74, P<0·05 and r = 0·83, P<0·01). Conclusion:, Pulsed Doppler-derived IVRt correlates well with PASP. The use of pulsed DTI for measurement of IVRt is simple, reproducible and easy to obtain. We propose this method as an additional non-invasive tool in the assessment of PASP. [source] | ||||||||||