ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The effects of four levels of activity on heart rate, blood pressure, cardiac index, total peripheral resistance index (TPRI), norepinephrine (NE) spillover rate, insulin sensitivity, and levels of lipids and some hormones were studied in 12 normal subjects. The randomized periods were (1) 4 weeks of below-sedentary activity, (2) 4 weeks of sedentary activity, (3) 4 weeks of 40 min of bicycling three times per week, and (4) 4 weeks of similar bicycling seven times per week. Exercise three times per week reduced resting blood pressure by 10/7 mm Hg (p < .01) and it was reduced by 12/7 mm Hg after exercise seven times per week (both p < .01). This was associated with reduction in TPRI, an increase in cardiac index, and cardiac slowing. At the highest level of activity, NE spillover rate, an index of sympathetic activity, fell to 35% of the sedentary value (p < .001) in eight of 10 subjects. In two other subjects NE spillover rate rose, although blood pressure and TPRI were reduced. Metabolic changes included lowering of total cholesterol, but high-densitv lipoprotein level was unchanged. Insulin sensitivity rose by 27% after exercise three times per week, icut –ec“ Ted to sedentary levels with seven times per week exercise. Maximum oxygen uptake inceasec i crly with activity. Exercise performed three times per week lowers blood pressure and should reduce ardiovascular risk. The same exercise seven times per week enhances physical performance with little further reduction in cardiovascular risk factors. Exercise is potentially a major nonpharmacologic method oflowering blood pressure.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Cardiac Doppler flow velocity studies were performed in normal human fetuses between 18 and 40 weeks of gestation. Two-dimensional linear array and sector scanning techniques were used for the initial evaluation of the fetuses, which included a standard ultrasound examination to determine normal anatomy and estimated gestational age and weight. Fetal cardiac ultrasound examination was then performed, with four-chamber, short-axis/great vessel, long-axis/left ventricular outflow tract, and aortic arch views obtained. Pulsed echo Doppler instrumentation was used to obtain flow velocity measurements through the tricuspid, pulmonary outflow, mitral, and aortic outflow regions. Calculation of transvalve volume flow for mitral and tricuspid valves was performed by combining the valve anulus sizes and calculated mean temporal velocities for the valves. Maximal flow velocities were greater through the tricuspid (mean maximal velocity 51 + 1.2 [SE] cm/sec) than through the mitral (47 + 1.1 cm/sec; p < .05) valve regions, with a wide range of scatter for results between fetuses but less than 6% average variation in the individual fetuses during gestation. For 18 fetuses, right heart dimensions and volume flows (mean 307 + 30 ml/kg/min) were greater than left heart dimensions and volume flows (232 ± 25 ml/kg/min). Doppler echocardiography may prove to be useful as an adjunct to imaging echocardiography for evaluation of fetal cardiac anatomy and function.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Cardiac Doppler flow velocity studies were performed in normal human fetuses between 18 and 40 weeks of gestation. Two-dimensional linear array and sector scanning techniques were used for the initial evaluation of the fetuses, which included a standard ultrasound examination to determine normal anatomy and estimated gestational age and weight. Fetal cardiac ultrasound examination was then performed, with four-chamber, short-axis/great vessel, long-axis/left ventricular outflow tract, and aortic arch views obtained. Pulsed echo Doppler instrumentation was used to obtain flow velocity measurements through the tricuspid, pulmonary outflow, mitral, and aortic outflow regions. Calculation of transvalve volume flow for mitral and tricuspid valves was performed by combining the valve anulus sizes and calculated mean temporal velocities for the valves. Maximal flow velocities were greater through the tricuspid (mean maximal velocity 51 + 1.2 [SE] cm/sec) than through the mitral (47 + 1.1 cm/sec; p < .05) valve regions, with a wide range of scatter for results between fetuses but less than 6% average variation in the individual fetuses during gestation. For 18 fetuses, right heart dimensions and volume flows (mean 307 + 30 ml/kg/min) were greater than left heart dimensions and volume flows (232 ± 25 ml/kg/min). Doppler echocardiography may prove to be useful as an adjunct to imaging echocardiography for evaluation of fetal cardiac anatomy and function.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

To assess the relative contributions of afterload mismatch and impaired contractility to pump dysfunction in patients with chronic aortic valve disease, simultaneous left ventricular cineangiography and micromanometry were performed in 56 patients: 21 with severe aortic stenosis, 16 with severe aortic regurtitation, and 19 normal control subjects. Left ventricular mass was increased in patients with aortic stenosis and aortic regurgitation (172 + 52 and 224 ± 63 g/m2, respectively, vs 89 + 16 for control subjects; p < .05) as were end-diastolic volume (101 ± 39 and 167 ± 44 vs 77 + 16 ml/m2; p < .05) and end-systolic volume (50 + 40 and 84 ± 43 vs 24 7 ml/m2; p < .05). Although ejection fraction was depressed in both abnormal groups (0.56 ± 0.18 for patients with aortic stenosis and 0.53 + 0.13 for those with aortic regurgitation vs 0.69 0.05 for control subjects; p < .05), the decrease in ejection fraction was disproportionate to the mild degree of afterload mismatch (end ejection stress 129 + 17 in patients with aortic stenosis and 154 ± 58 in those with aortic regurgitation vs 117 46 kdyn/cm2 in control subjects; p = NS) with 10 of 21 patients with aortic stenosis and 12 of 16 patients with aortic regurgitation falling below the 95% prediction limit of the linear inverse relationship between ejection fraction and end-systolic stress for controls (EF = 0.78 – 0.00074.ESS). The maximum stress:volume index ratio, which is an index of inotropic state that is independent of preload but sensitive to afterload, was also depressed in patients with aortic stenosis and aortic regurgitation (3.8 ± 1.4 and 2.5 ± 0.9 vs 5.0 1.3 kdyn/cm5/m2 for control subjects; p < .05), and first-order partial correlation demonstrated that this decrease was inversely related to left ventricular mass index. Thus, although afterload mismatch may adversely affect ventricular performance in patients with aortic valve disease, extensive hypertrophy and contractile dysfunction appear to be the major determinants of pump dysfunction.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

While aortic root dilatation and valvular dysfunction have been well-documented in osteogenesis imperfecta (01), the nature and extent of cardiovascular involvement in 01 have not been clearly delineated. A clinical and echocardiographic survey involving 109 individuals with various nonlethal 01 syndromes from 66 separate families was undertaken. Clinically discernible valvular dysfunction was encountered in only four of the 109 individuals (aortic regurgitation in two, aortic stenosis in one, and mitral valve prolapse in one), none of whom were related. Aortic root dilatation was recognized echocardiographically in eight (12.1%) of 66 individuals comprising a subset of the sample in which each family was represented by a single individual. The extent of the aortic root dilatation was mild (the largest dimension measuring 4.3 cm) and was unrelated to the age of the individual. Dilatation was seen in each of the different 01 syndromes but was strikingly segregated within certain families (p < .001). In the same subset of 66 individuals, mitral valve prolapse was encountered in two or 6.9% of the 29 individuals aged 15 years or greater in whom adequate studies were obtained. This observed frequency was not different from that seen in a normal adult population. Aortic root dilatation appears to represent a distinct phenotypic trait in patients with 01 that is nonprogressive and occurs in about 12% of affected individuals. Whether mitral valve prolapse should be considered as a part of the cardiovascular phenotype in 01, or alternately segregates as an independent autosomal dominant trait has yet to be determined.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID