ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The clinical and morphologic features of hypertrophic cardiomyopathy in 20 patients recognized as having cardiac disease in the first year of life are described. Fourteen of these 20 infants were initially suspected of having heart disease solely because a heart murmur was identified. However, the infants showed a variety of clinical findings, including signs of marked congestive heart failure (in the presence of nondilated ventricular cavities and normal or increased left ventricular contractility) and substantial cardiac enlargement on chest radiograph. Other findings were markedly different from those usually present in older children and adults with hypertrophic cardiomyopathy (e.g., right ventricular hypertrophy on the ECG and cyanosis). Consequently, in 14 infants, the initial clinical diagnosis was congenital cardiac malformation other than hypertrophic cardiomyopathy.Twelve of the 14 infants who underwent left-heart catheterization showed substantial obstruction to left ventricular outflow (peak systolic pressure gradient 35 mm Hg). However, unlike older patients with hypertrophic cardiomyopathy, infants with this condition commonly had marked obstruction to right ventricular outflow (35-106 mm Hg) (nine patients); in six patients, the magnitude of obstruction to right ventricular outflow was at least as great as that to left ventricular outflow.Asymmetric hypertrophy of the ventricular septum relative to the left ventricular free wall was present in the 16 patients who had echocardiographic or necropsy examination. Ventricular septal thickening was substantial in patients studied both before and after 6 months of age (mean 16 mm), indicating that in patients with hypertrophic cardiomyopathy, marked left ventricular hypertrophy may be present early in life and is probably congenital.The clinical course was variable in these patients, but the onset of marked congestive heart failure in the first year of life appeared to be an unfavorable prognostic sign; nine of the 11 infants with congestive heart failure died within the first year of life. In infants with hypertrophic cardiomyopathy, unlike older children and adults with this condition, sudden death was less common (two patients) than death due to progressive congestive heart failure.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Verapamil and placebo were compared in patients with stable, effort-induced angina. Singleblind dose titration (240, 360 and 480 mg/day) preceded a double-blind crossover. Among the 18 patients who completed graded exercise stress tests with reproducible pretreatment effort-limiting angina, exercise duration increased from 348 + 127 seconds (SD) before treatment to 494 + 182 seconds after verapamil (p< 0.001), but did not change after placebo. Compared with placebo, verapamil reduced the weekly number of anginal episodes from 4.54 + 5.03 to 2.44 3.30 (p< 0.05) and reduced nitroglycerin consumption from 3.46 i 5.30 to 1.55 ± 2.89 tablets per week (p< 0.05). Of 26 patients who completed the single-blind dose titration, 16 were improved (> 1 minute) at a dosage of 240 or 360 mg/day. No patient improved (> 1 minute) on 480 mg/day who had not already improved on a lower dose, but side effects requiring reduction in dosage occurred in seven patients receiving 480 mg of verapamil per day. Verapamil is an effective antianginal drug that appears most efficacious at a dose of 360 mg/day, but side effects are common at a dose of 480 mg/day.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The blood pressure response in hypertensive subjects to chronic treatment with verapamil, a calcium antagonist (or, more precisely, a slow-channel inhibitor), was studied using the Oxford system for continuous monitoring of intraarterial blood pressure. Sixteen patients underwent continuous monitoring over a 48-hour period before and after at least 6 weeks of therapy (dose range 120-160 mg three times daily). Each monitoring period included physiologic tests designed to show the effects of different types of exercise. Verapamil produces a consistent reduction of blood pressure over 24 hours, but particularly during the day. Heart rate was similarly reduced. There was no evidence of postural hypotension, and the absolute responses to dynamic and isometric exercise were reduced. The degree of reduction of the blood pressure was consistent, suggesting that slow-channel inhibitors may be appropriate for antihypertensive therapy.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

We studied the association between the outcome of antihypertensive care and three items of that care among 230 hypertensive steelworkers who were referred to 83 physicians. The first item was the decision to treat some patients but not others: 63% of the patients were prescribed antihypertensive drugs and the mean decrease in their diastolic blood pressure (DBP) was greater than that among untreated patients (12.2 ± 0.84 vs 7.8 ± 0.83 mm Hg [± SEMI, p < 0.001). The second item was the vigor of prescribed medication: Patients prescribed more vigorous treatments had lower DBP (p< 0.005). Third, patient compliance was related to achieving a goal DBP of less than 90 mm Hg (p< 0.05) and the product of prescribed vigor and compliance was highly associated with DBP response (p< 0.0001). These results stand in contrast to those of previous studies that failed to detect associations between various other items of the care process and the outcome of antihypertensive care.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Twenty sodium-replete patients with hypertension were allocated either to a placebo or to a captopril treatment group. Each patient was investigated in rest-recumbent (RR) and rest-sitting (RS) positions and during an uninterrupted, graded, submaximal exercise test (up to the anaerobic threshold) before treatment, and with a similar protocol 75 minutes after treatment with captopril or placebo on the same morning. Captopril decreased brachial intraarterial pressure by 7/4 mm Hg at RR, by 16/10 mm Hg at RS, and by 19/10 mm Hg during exercise (p< 0.001), based on a decrease of systemic vascular resistance (p< 0.001). Slight increases of cardiac output and of heart rate were noted at rest; cardiac output was not significantly affected during exercise, but the increase of heart rate of 2.4 beats/mm was significant (p< 0.01). Captopril decreased pulmonary artery (p< 0.05) and capillary wedge pressures (p< 0.001), with unchanged pulmonary vascular resistance.The data indicate that the action of captopril is characterized by arteriolar and possibly venous dilatation both at rest and during exercise. Pulmonary vascular resistance, however, is not affected.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

The effects of angiotensin-converting enzyme inhibitor (CEI) SQ14225 on infarct size and regional myocardial blood flow were studied in 21 anesthetized dogs subjected to 6 hours of coronary occlusion. An area of myocardium at risk of necrosis was determined in vivo after 15 minutes of coronary occlusion but before CEI treatment (AR1) using an autoradiographic technique and after treatment after 6 hours of coronary occlusion (AR2) using a fluorescent dye technique. An in vitro area at risk (AR8), which measures coronary bed size, was determined by injecting Monastral dye postmortem. Infarct size was determined by planimetry of unstained myocardium after incubating heart slices in triphenyltetrazolium chloride. Regional myocardial blood flow (RMBF) was measured by injecting tracer microspheres simultaneously with measurements of AR1 and AR2. In 11 saline-treated control dogs (group A), infarct size averaged 93 ± 8% of AR1, 96 i 2% of AR2 and 75 ± 6% of AR9, respectively. In 10 dogs treated with CEI (0.25 mg/kg/hour) between 30 minutes and 6 hours after coronary occlusion (group B), infarct size was smaller and averaged 68 ± 5% of AR1 (p< 0.01), 79 ± 5% of AR2 (p< 0.005), and 57 ± 7% of AR3 (p< 0.05). RMBF in the ischemic zone remained constant in group A but increased by 62 ± 26% in group B (p< 0.025). In group B, mean arterial pressure decreased from 115 ± 6 to 103 ± 7 mm Hg (p< 0.025) between 30 minutes and 6 hours after coronary occlusion and left atrial pressure decreased from 9.0 ± 1.8 to 5.7 ± 0.8 mm Hg (p< 0.0025). These measurements did not change in group A. Thus, CEI is potent in reducing infarct size in the dog after coronary occlusion. It may act by increasing collateral flow to the ischemic zone and reducing afterload.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

Nifedipine has been proposed as an agent to preserve viability and function of ischemic myocardium. We studied 23 open-chest dogs that underwent carotid-to-left anterior coronary artery perfusion with flow probe and perfusion pressure monitoring. Segment length was measured with ultrasonic crystals in the ischemic and nonischemic endocardium. Myocardial blood flow was measured with radioactive microspheres. Partial coronary occlusion was performed to 25 mm Hg diastolic perfusion pressure. Ten dogs received intracoronary nifedipine, 10 fig, and 13 dogs received i.v. nifedipine, 3, g/kg/min. Nifedipine resulted in an increase in segmental shortening in both groups, but nonischemic zone shortening did not change in either group. Nifedipine did not affect myocardial blood flow in the ischemic zone, but increased flow in the nonischemic zone in the group that received i.v. nifedipine. Thus, nifedipine appears to have a direct beneficial effect on ischemic myocardium.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

A problem in accurately measuring regional myocardial blood flow by radiation washout techniques is the inability to localize precisely the origin of radiation in tissue. We developed a new approach for in vivo localization and quantification of regional blood flow. A miniature, silicon, solid-state, avalanche radiation detector, which measures the low-penetrating radiation from commonly available radionuclides, was constructed. Low-penetrating radiation has a limited range in tissue, and by selecting appropriate tracers, we vary the volume that our probe detects. The volume of the heart monitored by the avalanche probe ranges from less than 0.01 to 1 cm3, depending on the radionuclide used and the collimator design. In open-chest dogs, 2-5 mCi of xenon-133 dissolved in saline were injected into coronary arteries and the probe was placed over regions of interest to measure regional myocardial blood flow by the Kety-Schmidt formula. Detection of xenon-133 decreased as an exponential function of distance, with less than 10% of radioactivity detected at 0.6 cm away from the radiation source. The measured detection volume for xenon-133 was approximated at 0.5 cm3. Measurements of regional blood flow with the probe correlated closely to epicardial flow measured with radioactive microspheres (r= 0.88 ± 0.04 [SDI) in five dogs, and to proximal coronary flow measured with electromagnetic meters (r= 0.87 ± 0.05) in five dogs. Repetitive measurements during stable hemodynamics were reproducible. Thus, with avalanche detectors we obtained reliable and valid in vivo measurements of myocardial blood flow from small volumes.

ISSN:0009-7322    

出版商:OVID    

年代:1982

数据来源: OVID