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Ejection Rate (ejection + rate)

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Life Sciences	50%

Selected Abstracts

Effect of reduced total blood volume on left ventricular volumes and kinetics in type 2 diabetes

ACTA PHYSIOLOGICA, Issue 1 2010
S. Lalande
Abstract Aim:, Although impaired left ventricular (LV) diastolic function is commonly observed in patients with type 2 diabetes, it remains unclear whether the impairment is caused by altered LV relaxation or changes in LV preload. The purpose of this study was to examine the influence of LV function and LV loading conditions on stroke volume in men with type 2 diabetes. Methods:, Cardiac magnetic resonance imaging scans were performed in eight men with type 2 diabetes and 11 non-diabetic men matched for age, weight and physical activity level. Total blood volume was determined with the Evans blue dye dilution technique. Results:, End-diastolic volume (EDV), the ratio of peak early to late mitral inflow velocity (E/A) and stroke volume were lower in men with type 2 diabetes than in non-diabetic individuals. Peak filling rate and peak ejection rate were not different between diabetic and non-diabetic individuals; however, men with type 2 diabetes had proportionally longer systolic duration than non-diabetic individuals. Heart rate was higher and total blood volume was lower in men with type 2 diabetes. The lower total blood volume was correlated with a lower EDV in men with type 2 diabetes. Conclusions:, Men with type 2 diabetes have an altered cardiac cycle and lower end-diastolic and stroke volume. A lower total blood volume and higher heart rate in men with type 2 diabetes suggest that changes in LV preload, independent of changes in LV relaxation or contractility, influence LV diastolic filling and stroke volume in this population. [source]

Sex influence on myocardial function with exercise in adolescents

AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2010
Thomas Rowland
Objectives: Ventricular systolic functional response to exercise has been reported to be superior in adult men compared to women. This study explored myocardial responses to maximal upright progressive exercise in late pubertal males and females. Methods: Doppler echocardiographic techniques were utilized to estimate myocardial function response to a bout of progressive cycle exercise. Results: Systolic functional capacity, as indicated by ejection rate (12.5 ± 2.8 and 13.1 ± 1.0 [×10,2] ml s,1 cm,2 for boys and girls, respectively) and peak aortic velocity (208 ± 45 and 196 ± 12 cm s,1, respectively) at maximal exercise, did not differ between the two groups. Similarly, peak values as well as increases in transmitral pressure gradient (mitral E flow velocity), ventricular relaxation (tissue Doppler imaging E,), and left ventricular filling pressure (E/E, ratio) as estimates of diastolic function were similar in males and females. Conclusions: This study failed to reveal qualitative or quantitative differences between adolescent boys and girls in ventricular systolic or diastolic functional responses to maximal cycle exercise. Am. J. Hum. Biol. 22:680,682, 2010. © 2010 Wiley-Liss, Inc. [source]

High temporal resolution SSFP cine MRI for estimation of left ventricular diastolic parameters

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2010
Ramkumar Krishnamurthy MS
Abstract Purpose: To obtain high temporal resolution (HTR) magnetic resonance (MR) steady-state free-precession (SSFP) cine cardiac images by using multichannel radiofrequency (RF) hardware and parallel imaging techniques; to study the effect of temporal resolution; and to compare the derived left ventricular (LV) diastolic filling parameters with echocardiographic results. Materials and Methods: HTR images were acquired in 13 healthy volunteers using a 1.5 T scanner with 32 RF channels and sensitivity encoding (SENSE) and k-t broad-use linear-acquisition speedup technique (k-t BLAST) imaging techniques. LV diastolic parameters were calculated and compared to conventional echocardiographic indices such as the isovolumic relaxation time (IVRT) and E/A ratio. The need for HTR was assessed and the MR results were compared with echocardiographic results. Results: The HTR (,6-ms) images yielded higher peak filling rates, peak ejection rates, and peak atrial filling rates. A progressive decline in filling and ejection rates was observed with worsening temporal resolution. The IVRTs and E/A ratios measured with MR versus echocardiography were in broad agreement. Also, SENSE and k-t BLAST yielded similar diastolic functional parameters. Conclusion: With SENSE or k-t BLAST and modern hardware, HTR cine images can be obtained. The lower temporal resolutions (30,50 ms) used in clinical practice reduce LV filling rates by ,30% and may hinder characterization of transient phenomena such as the IVRT. J. Magn. Reson. Imaging 2010;31:872,880. ©2010 Wiley-Liss, Inc. [source]