摘要:

NO ABSTRACT

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

NO ABSTRACT

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTWe sought to determine whether digitalis augments cardiopulmonary baroreflex control offorearm vascular resistance in normal young men. Cardiopulmonary baroreceptor input was reduced with lower body negative pressure (LBNP) at 10 and 20 mm Hg, which decreased central venous pressure but did not alter blood pressure or heart rate. Decreases in forearm blood flow and increases in forearm vascular resistance with LBNP were greater after administration of lanatoside C (Cedilanid) than before, and the slope of the regression line relating changes in central venous pressure and those in forearm vascular resistance was steeper after lanatoside C. Vasoconstrictor responses to the cold pressor test did not differ before and after lanatoside C, which suggested that augmented responses to LBNP after the drug were not caused by a generalized change in reflex control. These results suggest that lanatoside C augments the tonic inhibitory influence of cardiopulmonary baroreceptors in normal men.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTDuring the past 4 years 196 patients with the idiopathic long QT syndrome were enrolled in a prospective international study conducted to obtain a better understanding of the clinical course of this unusual repolarization disorder. The mean patient age was 24 years, 64% were female, and 88% had family members with QT prolongation. During an average follow-up of 26 months per patient, four patients died suddenly (1.3% per year) and 27 patients had one or more syncopal episodes (8.6% per year). Multivariate analysis identified congenital deafness, history of syncope, female gender, and a documented episode of torsades de pointes or ventricular fibrillation as independent risk factors for postenrollment syncope or sudden death. Two types of treatment (left stellate ganglionectomy and, 3‐blocker therapy) were associated with a significant reduction in the occurrence of cardiac events during follow-up.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTAnalysis of the Framingham Heart Study experience between 1958 and 1970 showed a progressive increase in the rate of treatment and control of hypertension. With cross-sectional criteria to define diastolic hypertension, the treatment rate rose from 35% in 1958 through 1960 to 69% in 1968 through 1970 (p < .001), and the treatment rate for sustained hypertension rose from 55% in 1958 through 1960 to 85% in 1968 through 1970 (p < .001). Treated hypertensive subjects had higher pretreatment values of blood pressure but not of other cardiovascular risk factors than untreated hypertensive subjects. Treatment was more successful in controlling hypertension in later years (p < .001), but in all years treatment reduced systolic and diastolic blood pressure without causing significant changes in mean serum cholesterol or glucose levels. In treated hypertensive subjects, the 8 year predicted risk of coronary heart disease declined by 2.3 events per 100 people compared with that in untreated hypertensive subjects (p < .0001). The observed incidence of coronary heart disease was consistent with these predictions and suggested that treatment may be especially beneficial in subjects who have systolic blood pressures of 180 mm Hg or higher and who are treated for more than 2 successive years.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTWe studied the relationship between myocardial contractile state and left ventricular functional response to exercise in 14 asymptomatic patients with isolated moderate-to-severe aortic regurgitation and six control subjects. The slope of the systolic blood pressure-left ventricular endsystolic volume (pressure-volume) relationship determined by radionuclide ventriculography during angiotensin infusion was used as an indirect measure of myocardial contractility and was compared with left ventricular ejection fraction at rest and during both isometric handgrip and dynamic bicycle exercise. The slope of the pressure-volume relationship was significantly lower in patients with aortic regurgitation than in the control subjects (1.75 ± 0.57 vs 2.78 ± 0.42, p < 0.01). The slope correlated exponentially with resting ejection fraction and was linearly related to changes in left ventricular ejection fraction during both handgrip and bicycle exercise. In patients with aortic regurgitation, resting ejection fraction may overestimate myocardial function. The slope of the pressure-volume relationship measured during afterload stress and left ventricular ejection fraction response to exercise intervention more reliably reflect the degree of left ventricular dysfunction.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTBecause of the uncertainty as to the extent to which cardiac size is determined by exercise training vs genetic endowment, this study investigated familial (genetic plus common family environment) vs nonfamilial influences on cardiac size. College-age monozygotic twins (group 1, 31 sets), dizygotic twins (group 2, 10 sets), siblings of like sex (group 3, six sets), and nonrelated subjects (group 4, 15 sets) underwent echocardiographic and electrocardiographic tests, measurement of maximum oxygen uptake (VO2max), and evaluation of pulmonary and body composition; mean intrapair differences of the four groups were compared. Mean intrapair differences in cardiac size varied as much for subjects in group 1 as for those in groups 2 and 3. However, subjects in groups 1, 2, and 3 had less variation (p < .05) than those in group 4. After the initial testing, 14 pairs of monozygotic twins, five sets of dizygotic twins, and six sets of siblings underwent 14 weeks of exercise training (both members participated) and all tests were repeated. After exercise training, subjects in group 1 still had as much intrapair variability in cardiac size as those in groups 2 and 3. The data suggest cultural familial influences are more important in determining cardiac size than nonfamilial influences or even genetic influences alone.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTOver a 3 year period we evaluated 23 patients (16 men, seven women) with apical hypertrophic cardiomyopathy by noninvasive and invasive methods. Sixteen patients had chest pain. In 17, results of cardiovascular examination were normal. The electrocardiogram showed precordial inverted T waves in all patients and these were of mild-to-moderate amplitude (<10 mm) in 18 and giant (>10 mm) in five. M mode echocardiography revealed a typical pattem of contraction and relaxation in the apical region of the left ventricle that was associated with significant hypertrophy. These findings were confirmed by two-dimensional echocardiography. Systolic anterior motion of the mitral valve was not observed nor was there any evidence of obstruction of the left ventricular outflow tract. Results of Doppler echocardiographic study of the mitral and aortic flow were normal in all patients but one who had mild mitral insufficiency. Radionuclide studies of 14 patients revealed a mean left ventricular ejection fraction of 66 ± 6% (range 55% to 79%), with normal left ventricular contraction in all patients but two with apical hypokinesis. In all six patients who underwent catheterization a characteristic appearance of the left ventricle at end-systole as well as abnormal end-diastolic contour were noted on the left ventricular angiogram, but the “ace of spades” configuration was seen in only one. We conclude that the 23 patients studied form a homogeneous group of individuals with nonobstructive apical hypertrophic cardiomyopathy, which differs in many respects from cardiomyopathies reported by other investigators.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTExertional fatigue is a major limiting symptom in patients with heart failure. To investigate the metabolic basis of this fatigue, we used gated nuclear magnetic resonance spectroscopy to compare inorganic phosphate (P), phosphocreatine (PCr) and pH levels, and fatigue (1 to 4+) during mild forearm exercise in eight normal men and nine men with heart failure. Wrist flexion every 5 sec for 7 min was performed at 1, 2, and 3 J (average power output = 0.2, 0.4, and 0.6 W). In both groups linear relationships were noted between power output and P/PCr; the slope of this relationship was used to compare PCr depletion patterns. At rest both groups had similar Pi/PCr ratios (normal subjects 0.12 ± 0.06, those with heart failure 0.15 ± 0.03) and pH (normal subjects 7.04 ± 0.13, those with heart failure 7.10 ± 0. 11). In normal subjects exercise resulted in a progressive increase in Pi/PCr (slope = 1.17 ± 0.20 Pi/PCr units/W), a reduction in pH only at 0.6 W (0.2 W: 7.03 ± 0.10, 0.4 W: 7.01 ± 0.10, 0.6 W: 6.88 ± 16) and moderate fatigue (0.2 W: 0 ± 0, 0.4 W: 1.3 ± 0.5, 0.6 W: 1.9 ± 0.6). In patients with heart failure exercise resulted in significantly greater fatigue at all workloads (0.2 W: 1.0 ± 0.5, 0.4 W: 1.9 ± 0.6, 0.6 W: 2.9 ± 0.5). This fatigue was associated with twice as rapid an increase in Pi/PCr (slope = 2.63 ± 2.14 PPCr units/W, p < .04 vs normal) and greater acidosis (0.2 W: 6.89 ± 0.11, 0.4 W: 6.78 ± 0.22, 0.6 W: 6.75 ± 0.23; p < .02 at 0.2 and 0.4 W vs normal). These data suggest that exertional fatigue in patients with heart failure may result from greater than normal PCr depletion and/or acidosis in the working muscle.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

ABSTRACTElectrophysiologic studies were performed in 15 patients with syncope and/or cardiac arrest who had the long QT syndrome and 11 control subjects who had normal QT invervals. The syndrome was familial in five patients and idiopathic in 10. All patients had a prolonged QT (546 68 msec, mean ± SD) and corrected QT (550 ± 51 msec). Incremental atrial pacing at cycle lengths of 600 to 400 msec resulted in shortening of the QT interval, but there was no significant difference in the magnitude or percent of shortening of the QT interval between patients with the long QT syndrome and control subjects. Intravenous propranolol did not influence the QT interval measured at fixed atrialpaced cycle lengths in patients with either the familial or idiopathic form of the syndrome. Programmed right and left ventricular stimulation with up to three extrastimuli before and during isoproterenol infusion did not induce sustained ventricular tachycardia or ventricular fibrillation in any of the patients. However, rapid polymorphic nonsustained ventricular tachycardia was induced in six of the 15 patients (40%). Neither the inducibility of nonsustained ventricular tachycardia nor the results of electropharmacologic testing with f-blockers proved to be of any prognostic value during the mean follow-up period of 28 ± 17 months. Electrophysiologic studies are of limited value in the diagnosis and treatment of patients with the long QT syndrome.

ISSN:0009-7322    

出版商:OVID    

年代:1985

数据来源: OVID