摘要:

SUMMARYSpectacular progress has occurred in cardiology during the past 30 years. The major advances that have resulted in the better methods of diagnosis and treatment of patients stem from basic research that was often unrelated to the ultimate practical application. An excellent example of this process is the evolution of the concept of,β blockade from the pharmacology laboratory to practical clinical application in a variety of conditions. The sequence of discovery, translation, and application depends on many factors, but most important is the trained, dedicated investigator. If progress is to continue, a constant supply of bright young men and women must enter careers in basic research and clinical investigation. Recent studies show that the pool of biomedical scientists is shrinkiing and fewer young people are selecting research careers; thus, the process upon which our future depends is threatened. The socioeconomic forces that tend to turn the potential stars of the future away from research careers have been identified, and they must be counterbalanced. For 30 years. the American Heart Association has been a leader in the conquest of heart disease through research. The faith of the Association in research must be reaffirmed. The relationship of today's basic research to the good medical care of the future must be explained to the people and to their elected representatives in words that they understand. Action must be taken to assure the continuation of the research enterprise that has been respoinsible for the progress of the last 30 years.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYThe use of digitalis after acute myocardial infarction Is controversial. The effect of digoxin on computer-quantitated thallium-201 perfusion scintigrams (TI-201), left ventricular (LV) ejection fraction (EF), and percentage of abnormally contracting LV regions (%ACR) was determined in 23 patients. A correlation was established between creatine kinase MB isoenzyme release and Initial radionuclide-gated blood pool wall motion estimates of EF (r= −0.73) and %ACR (r= 0.71). After radionuclide assments, 14 patients received digoxin 18 ± 23 hours (mean ± SD) after the rise in CK-MB from baseline, while the remaining nine patients served as controls. In the control group, the mean EF was 0.33 ± 0.12 on the first study and 0.30 ± 0.08 on the second study (p= NS). In the digoxin group, the EF after digoxin administration (mean 0.33 ± 0.11) was significantly different from the initial EF (mean 0.29 ± 0.09,p< 0.03); however, digoxin had no apparent effect on infarct size as assessed by sequential %ACR and TI-201 perfusion data. These data indicate that digoxin resulted in a minimal but significant improvement in EF that did not occur at the expense of LV perfusion or regional wall motion.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYAmrinone has been shown to exhibit a potent inotropic effect in patients with heart failure secondary to congestive cardiomyopathy, but its effects on myocardial oxygen consumption (MVO2) and coronary blood flow (CBF) are unknown. Accordingly, the hemodynamic, myocardial metabolic and ECG responses to amrinone (2.5 mg/kg i.v. over 1 hour) were measured in nine patients with congestive heart failure secondary to coronary artery disease. Increases were observed in cardiac index (1.3 ± 0.4 to 2.2 ± 0.7 I/min/m2) and left ventricular stroke work (10.6 ± 3.0 to 19.2 ± 6.3 g-m/m2), and decreases in mean pulmonary wedge (31 ± 5 to 26 ± 4 mm Hg), mean pulmonary artery (44 ± 8 to 36 ± 7 mm Hg) and mean right atrial pressures (18 ± 4 to 10 ± 4 mm Hg), myocardial arteriovenous oxygen difference (129 ± 19 to 109 ± 17 ml/l), CBF (215 ± 117 to 178 ± 84 ml/min) and MVO2(27 + 14 to 19 ± 9 ml/min). All changes were significant (p< 0.01). No significant changes occurred in aortic mean pressure, heart rate, myocardial lactate extraction or ECG, and no patient developed angina. In explaining the decline in MVO2, it is possible that the increase in contractility was more than offset by the reductions in preload and afterload. The amrinone-induced hemodynamic improvement in patients with congestive heart failure secondary to coronary artery disease was associated with reductions in MVO2 and CBF and no evidence of myocardial ischemia.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYAmrinone has been shown to exhibit a potent inotropic effect in patients with heart failure secondary to congestive cardiomyopathy, but its effects on myocardial oxygen consumption (MVO2) and coronary blood flow (CBF) are unknown. Accordingly, the hemodynamic, myocardial metabolic and ECG responses to amrinone (2.5 mg/kg i.v. over 1 hour) were measured in nine patients with congestive heart failure secondary to coronary artery disease. Increases were observed in cardiac index (1.3 ± 0.4 to 2.2 ± 0.7 I/min/m2) and left ventricular stroke work (10.6 ± 3.0 to 19.2 ± 6.3 g-m/m2), and decreases in mean pulmonary wedge (31 ± 5 to 26 ± 4 mm Hg), mean pulmonary artery (44 ± 8 to 36 ± 7 mm Hg) and mean right atrial pressures (18 ± 4 to 10 ± 4 mm Hg), myocardial arteriovenous oxygen difference (129 ± 19 to 109 ± 17 ml/l), CBF (215 ± 117 to 178 ± 84 ml/min) and MVO2 (27 + 14 to 19 ± 9 ml/min). All changes were significant (p< 0.01). No significant changes occurred in aortic mean pressure, heart rate, myocardial lactate extraction or ECG, and no patient developed angina. In explaining the decline in MVO2, it is possible that the increase in contractility was more than offset by the reductions in preload and afterload. The amrinone-induced hemodynamic improvement in patients with congestive heart failure secondary to coronary artery disease was associated with reductions in MVO2and CBF and no evidence of myocardial ischemia.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYCaptopril (SQ 14,225), an oral angiotensin converting-enzyme inhibitor, was administered to 11 patients with severe congestive heart failure (CHF). Peak effect was observed at 1.5 hours after administration. At peak effect right atrial pressure fell from 3.4 to 0.0 mm Hg, pulmonary capillary wedge pressure (PCW) fell from 22.7 to 12.3 mm Hg, mean arterial pressure (MAP) fell from 79.5 to 62.1 mm Hg, systemic vascular resistance (SVR) fell from 1989 to 1370 dyn-sec-cm-5, pulmonary vascular resistance fell from 843 to 523 dyn-sec-cm-, and cardiac index (CI) rose from 1.96 to 2.43 1/min/m2. These were all statistically significant. Control plasma renin activity (PRA) was elevated (25.9 ng/ml/hr) and correlated with resting PCW (r= 0.65). The acute hemodynamic response was related to PRA: a fall in MAP (r= 0.74), a fall in PCW (r= 0.80), a fall in SVR (r= 0.45) and a rise in CI (r= 0.45). Eight patients were placed on chronic captopril therapy. After 2 or more months, their exercise time was significantly increased, from 6.8 to 11.7 minutes. Their cardiothoracic ratios showed a significant decrease, from 0.55 to 0.52, and most patients reported symptomatic improvement. Chronic response was not predicted by acute hemodynamic response. Captopril is therefore a vasodilator with both arterial and venous effects that are at least partially caused by inhibition of the renin-angiotensin system. It may be useful for the treatment of CHF.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYFourteen patients with critical aortic stenosis (valve area ⩽ 0.4 cm2/m2), a history of advanced congestive heart failure, left ventricular ejection fraction less than 0.45 (mean 0.28 ± 0.03) and no other valvular lesions or obstructive coronary artery disease were studied to assess prognosis with aortic valve replacement. Eleven of 14 (79%) survived surgery; 10 of these 11 showed major clinical improvement postoperatively and form group 1. The three patients who died and the patient who did not improve form group 2. Although group 2 had higher preoperative values for aortic valve area and left ventricular end-diastolic volume and lower ejection fraction and cardiac output than group 1, none of these factors alone reliably predicted outcome. The mean systolic gradient was an important predictor of outcome: No patient with a mean systolic gradient ± 30 mm Hg had a good outcome, irrespective of valve area or other hemodynamic variables. Ejection fraction was plotted against left ventricular wall stress for both groups. For group 1, there was a close linear relation that could be extrapolated back to normal wall stress and normal ejection fraction. This suggested afterload mismatch as a major cause for this group's depressed ejection fraction. In group 2 ejectionf raction was lower for any given wall stress, suggesting depressed contractility, rather than afterload mismatch, as the cause of the left ventricular dysfunction. Thus, either afterload mismatch or depressed contractility may result in depressed ejection fraction in patients with aortic stenosis; which one predominates may have major prognostic importance.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYThe electrocardiographic and ventilatory responses of 15 denervated heart patients who had undergone cardiac transplantation and 14 age-matched, normally innervated men were compared to assess the pattern of response to graded treadmill exercise. A 5-minute postexercise venous lactate sample was also obtained. Respiratory exchange ratio and ventilation (VE) were higher in denervated patients than in normals during submaximal exercise. Peak values (normals vs denervated) for heart rate (172 vs 159 beats/min), blood pressure (189 vs 167 mm Hg), oxygen uptake (37 vs 25 ml/kg/min), oxygen pulse (0.22 vs 0.16 ml/kg/beat) and work time (26.2 vs 18.0 minutes) were higher in normals than in cardiac transplant recipients. Peak ventilatory equivalent (2.14 vs 3.13 1/ml/kg) and lactate values were higher for transplants than for normal subjects, but there were no significant intergroup differences in peak VEor in the respiratory exchange ratio. In cardiac transplant recipients, work time correlated inversely with a measure of rejection history (r= −0.59, p < 0.01). The response of cardiac transplant recipients to treadmill work differs from that of normal men and reflects a diminished ability to meet the oxygen demands of the exercising periphery.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYThe electrocardiographic and ventilatory responses of 15 denervated heart patients who had undergone cardiac transplantation and 14 age-matched, normally innervated men were compared to assess the pattern of response to graded treadmill exercise. A 5-minute postexercise venous lactate sample was also obtained. Respiratory exchange ratio and ventilation (VE) were higher in denervated patients than in normals during submaximal exercise. Peak values (normals vs denervated) for heart rate (172 vs 159 beats/min), blood pressure (189 vs 167 mm Hg), oxygen uptake (37 vs 25 ml/kg/min), oxygen pulse (0.22 vs 0.16 ml/kg/beat) and work time (26.2 vs 18.0 minutes) were higher in normals than in cardiac transplant recipients. Peak ventilatory equivalent (2.14 vs 3.13 1/ml/kg) and lactate values were higher for transplants than for normal subjects, but there were no significant intergroup differences in peak VEor in the respiratory exchange ratio. In cardiac transplant recipients, work time correlated inversely with a measure of rejection history (r = −0.59,p< 0.01). The response of cardiac transplant recipients to treadmill work differs from that of normal men and reflects a diminished ability to meet the oxygen demands of the exercising periphery.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARYA mechanical model of a branched coronary artery with a graft bypassing an 80% stenosis of one branch was used to study the reduction in coronary flow due to stenosis of the bypass graft. Flow Reynolds number and ratio of aortic pressure to dynamic pressure were matched to the living system. Changes in coronary flow were measured for a range of stenoses (0-100%) of bypass grafts with graft-to-coronary-diameter ratios of 4:1, 3:1, 2: 1 and 1:1 for conditions that simulated rest and exercise. The results of these studies indicate that: 1) marked stenosis of bypass grafts is needed to decrease coronary flow in the resting state, and even moderate stenosis will decrease flow during exercise when the diameter of the bypass is large relative to the coronary artery; 2) coronary flow is decreased with mild stenosis for bypass grafts of the same diameter as the coronary artery; and 3) a marked decrease in flow due to stenosis of a bypass graft occurs only when the diameter of a stenosis in a graft is less than the diameter of the coronary artery.

ISSN:0009-7322    

出版商:OVID    

年代:1980

数据来源: OVID