Home About us Contact
|
Home About us Contact | ||
|
|
||
Diastolic Performance (diastolic + performance)
Selected AbstractsAn Echocardiographic Analysis of the Long-Term Effects of Carvedilol on Left Ventricular Remodeling, Systolic Performance, and Ventricular Filling Patterns in Dilated CardiomyopathyECHOCARDIOGRAPHY, Issue 7 2005Peter S. Rahko M.D. Background: The long-term clinical benefit of beta blockade is well recognized, but data quantifying long-term effects of beta blockade on remodeling of the left ventricle (LV) is limited. Methods: This consecutive series evaluates the long-term response of the LV to the addition of carvedilol to conventional therapy for dilated cardiomyopathy. There were 33 patients who had a LV ejection fraction <45%, LV enlargement and symptomatic heart failure. Quantitative Doppler echocardiography was performed at baseline 6, 12, 24, and 36 months after initiation of carvedilol to evaluate LV ejection fraction, LV volume, wall stress, mass, regional function, and diastolic performance. Results: Compared to baseline there was a significant and sustained reduction in end-systolic volume and end-systolic wall stress with a corresponding improvement in LV ejection fraction. The LV mass did not decline but relative wall thickness increased toward normal. An analysis of regional wall motion responses showed an improvement in all areas, particularly the apical, septal, and lateral walls that was significantly more frequent in patients with a nonischemic etiology. Filling patterns of the LV remained abnormal throughout the study but changed with therapy suggesting a decline in filling pressures. These changes were sustained for 3 years. Conclusion: (1) The addition of carvedilol to conventional therapy for a dilated cardiomyopathy significantly improves LV ejection fraction and reduces LV end-systolic volume and wall stress for at least 3 years, (2) the response to 6 months of treatment predicts the long-term response, (3) the typical response is partial improvement of the LV, complete return to normal size, and function is uncommon, and (4) abnormalities of LV filling persist in virtually all patients throughout the course of treatment. [source] 2-D transmitral flows simulation by means of the immersed boundary method on unstructured gridsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2002F. M. Denaro Abstract Interaction between computational fluid dynamics and clinical researches recently allowed a deeper understanding of the physiology of complex phenomena involving cardio-vascular mechanisms. The aim of this paper is to develop a simplified numerical model based on the Immersed Boundary Method and to perform numerical simulations in order to study the cardiac diastolic phase during which the left ventricle is filled with blood flowing from the atrium throughout the mitral valve. As one of the diagnostic problems to be faced by clinicians is the lack of a univocal definition of the diastolic performance from the velocity measurements obtained by Eco,Doppler techniques, numerical simulations are supposed to provide an insight both into the physics of the diastole and into the interpretation of experimental data. An innovative application of the Immersed Boundary Method on unstructured grids is presented, fulfilling accuracy requirements related to the development of a thin boundary layer along the moving immersed boundary. It appears that this coupling between unstructured meshes and the Immersed Boundary Method is a promising technique when a wide range of spatial scales is involved together with a moving boundary. Numerical simulations are performed in a range of physiological parameters and a qualitative comparison with experimental data is presented, in order to demonstrate that, despite the simplified model, the main physiological characteristics of the diastole are well represented. Copyright © 2002 John Wiley & Sons, Ltd. [source] Xanthine oxidase inhibitor allopurinol attenuates the development of diabetic cardiomyopathyJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 8b 2009Mohanraj Rajesh Abstract In this study, we investigated the effect of the xanthine oxidase (XO) inhibitor, allopurinol (ALP), on cardiac dysfunction, oxidative-nitrosative stress, apoptosis, poly(ADP-ribose) polymerase (PARP) activity and fibrosis associated with diabetic cardiomyopathy in mice. Diabetes was induced in C57/BL6 mice by injection of streptozotocin. Control and diabetic animals were treated with ALP or placebo. Left ventricular systolic and diastolic functions were measured by pressure,volume system 10 weeks after established diabetes. Myocardial XO, p22phox, p40phox, p47phox, gp91phox, iNOS, eNOS mRNA and/or protein levels, ROS and nitrotyrosine (NT) formation, caspase3/7 and PARP activity, chromatin fragmentation and various markers of fibrosis (collagen-1, TGF-,, CTGF, fibronectin) were measured using molecular biology and biochemistry methods or immunohistochemistry. Diabetes was characterized by increased myocardial, liver and serum XO activity (but not expression), increased myocardial ROS generation, p22phox, p40phox, p47phox, p91phox mRNA expression, iNOS (but not eNOS) expression, NT generation, caspase 3/7 and PARP activity/expression, chromatin fragmentation and fibrosis (enhanced accumulation of collagen, TGF-,, CTGF and fibronectin), and declined systolic and diastolic myocardial performance. ALP attenuated the diabetes-induced increased myocardial, liver and serum XO activity, myocardial ROS, NT generation, iNOS expression, apoptosis, PARP activity and fibrosis, which were accompanied by improved systolic (measured by the evaluation of both load-dependent and independent indices of myocardial contractility) and diastolic performance of the hearts of treated diabetic animals. Thus, XO inhibition with ALP improves type 1 diabetes-induced cardiac dysfunction by decreasing oxidative/nitrosative stress and fibrosis, which may have important clinical implications for the treatment and prevention of diabetic cardiomyopathy and vascular dysfunction. [source] Preserving Normal Ventricular Activation Versus Atrioventricular Delay Optimization During Pacing: The Role of Intrinsic Atrioventricular Conduction and Pacing RatePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2000IVAN ILIEV ILIEV The purpose of the study was to compare the effects of DDD pacing with optimal AV delay and AAI pacing on the systolic and diastolic performance at rest in patients with prolonged intrinsic AV conduction (first-degree AV block). We studied 17 patients (8 men, aged 69 ± 9 years) with dual chamber pacemakers implanted for sick sinus syndrome in 15 patients and paroxysmal high degree AV block in 2 patients. Aortic flow and mitral flow were evaluated using Doppler echocardiography. Study protocol included the determination of the optimal A V delay in the DDD mode and comparison between AAI and DDD with optimal A V delay for pacing rate 70/min and 90/min. Stimulus-R interval during AAI (AHI) was 282 ± 68 ms for rate 70/min and 330 ± 98 ms for rate 90/min (P < 0.01). The optimal A V delay was 159 ± 22 ms, A V delay optimization resulted in an increase of an aortic flow time velocity integral (AFTVI) of 16%± 9%. At rate 70/min the patients with ARI , 270 ms had higher AFTVI in AAI than in DDD (0.214 ± 0.05 m vs 0.196 ± 0.05 m, P < 0.01), while the patients with ARI > 270 ms demonstrated greater AFTVI under DDD compared to AAI(0.192 ± 0.03 m vs 0.166 ± 0.02 m, P < 0.01). At rate 90/min AFTVI was higher during DDD than AAI (0.183 ± 0.03 m vs 0.162 ± 0.03 m, P < 0.01). Mitral flow time velocity integral (MFTVI) at rate 70/min was higher in DDD than in AAI (0.189 ± 0.05 m vs 0.173 ± 0.05 mP < 0.01), while at rate 90/min the difference was not significant in favor of DDD (0.149 ± 0.05 m vs 0.158 ± 0.04 m). The results suggest that in patients with first-degree AV block the relative impact of DDD and AAI pacing modes on the systolic performance depends on the intrinsic AV conduction time and on pacing rate. [source] | ||||||||||