摘要:

Resting hemodynamics improve during vasodilator administration in patients with congestive heart failure (CHF), but the effects of these agents on exercise is unknown. Twenty-two patients with class II or III CHF performed bicycle exercise to symptomatic maximum before and 90 minutes after random doubleblind administration of oral hydralazine (100 mg) and isosorbide dinitrate (40 mg) (11 patients, group 1) or placebo (11 patients, group 2). Exercise duration was unchanged after treatment in either group. Maximal oxygen consumption changed insignificantly in both groups, from 12.6 ± 1.2 (SEM) to 13.6 ± 1.6 ml/kg/min in group 1, and from 11.7 ± 1.4 to 13.4 ± 1.7 ml/kg/min in group 2. Maximal cardiac index was unchanged in both group 1 (4.00 ± 0.33 to 4.41 ± 0.29 1/min/m2) and group 2 (4.11 ± 0.43 to 4.14 ± 0.42 1/min/m2). Systemic vascular resistance at peak exercise was also unchanged in both group 1 (14.1 1.6 to 11.8 1.0 units) and group 2 (14.7 1.6 to 13.5 ± 1.6 units). At submaximal exercise (300 kilopond-meters/min), however, cardiac index after treatment increased in group 1 (0.51 + 0.18 1/min/m2,p < 0.05) and systemic vascular resistance decreased (-3.3 ± 1.3 units, p < 0.05), but were unchanged in group 2. Thus, although vasodilators do not improve maximal exercise capacity acutely, they can improve hemodynamics at lower work loads which may, therefore, be better tolerated in patients with CHF.

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Data were collected prospectively on 7553 consecutive patients undergoing coronary arteriog-raphy. The studies were performed at 13 clinics of the Collaborative Study of Coronary Artery Surgery (CASS) using brachial and femoral techniques.There were eight deaths 0-24 hours and seven deaths 24-48 hours after arteriography (2/1000). There were 15 non-fatal myocardial infarctions (MIs) 0-24 hours and four MIs 24-48 hours after arteriography (2.5/1000). Of 657 cases with left main stenosis 50%, five died and three had MI. Left main disease in-creased risk of desth by 6.8 times (p < 0.001). Other factors increasing risk were unstable angina, congestive heart failure, multiple prematurs ventricular contractions, and hypertension.Of the 1187 patients studied fr;om the brachial artery, six died (0.51%) and five had MIs (0.42%). In 6328 patients studied from the femoral artery, nine died (0.14%) and 14 had MIs (0.22%). The brachial artery technique increased the risk of death 3.6 times compared with the femoral approach (p < 0.05). This result did not apply when analysis was yestricted to laboratories with 80% or more brachial procedures. Risk was not altered by heparin. I'hus, a prospective, multicenter analysis of complications reveals low risk of coronary arteriography but significant difference between two techniques.

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

We examined early mortality (within 30 days) and survival (beyond 30 days) after acute myocardial infarction in 221 patients by screening 158 variables measured soon after the patient's admission to the hospital. Nineteen of these measurements had predictive value, but each variable alone was relatively insensitive. Therefore, we subjected groups of variables to stepwise discriminant function analysis and classification rates were estimated by calculating 95% confidence intervals using a jackknife procedure. When factors from the history, physical examination, and noninvasive assessment were combined, we identified 70% of deaths (confidence interval 48-80%) and 94% (90-98%) of survivors; when 11 selected variables including hemodynamic data were combined, we identified 86% (66-98%) of deaths and 96% (92-100%) of survivors (93% overall accuracy). We further tested the validity of this method in a subsequent series of 150 patients. Using the original discriminant functions, classification rates based on noninvasive and hemodynamic data fell within predicted limits, although the number of patients studied hemodynamically was unrepresentative and too small to allow overall predictive accuracy. Therefore, we randomly divided the entire population (371 patients) into a base sample from which we constructed new discriminant functions, with which we classified the remaining patients. The classification rates for the validation sample fell within the predicted confidence intervals. Thus, our method provides a reliable approach for predicting the risk of early death or the likelihood of survival in patients soon after acute myocardial infarction.

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Coronary collaterals were evaluated at arteriography within 1 year of the onset of symptoms of coronary disease in 73 patients with transmural myocardial infarction (TMI), 63 patients with subendocardial myocardial infarction (SMI), and 164 patients with angina pectoris (AP) alone. An occluded artery was present in 79% of patients with TMI, 70% of patients with SMI and elevated serum enzymes, and 42% of patients with AP. Collateral vessels supplied the occluded artery in 91% of patients with AP, 93% of patients with SMI all had postinfarction AP - and 78% of patients with TMI and postinfarction AP, but in only 35% of patients with TMI and no postinfarction AP (p < 0.01). With the treadmill stress test in patients with AP alone and coronary lesions in the anterior wall coronary distribution, 97% had ischemia in leads V4 to V,. Only 25% of patients with coronary lesions in the inferior wall coronary distribution had ischemia in leads III and aVF (positive group) and 75% did not (false negative group). The affected artery was occluded and supplied by collaterals in only 9% of patients of the positive group, but in 57% of the false negative group (p < 0.01). These data and additional findings in the infarction syndromes suggest that in TMI and SMI the presence of collaterals maintains a peri-infarction ischemic zone with subsequent AP. In patients with AP alone, the treadmill stress test is highly predictive of coronary disease in the anterior but not in the inferior wall coronary distribution, in part because of the influence of collaterals.

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Frequency analyses of the first heart sound (S,) were performed in 80 normal subjects and 80 postinfarction patients. A readily recognizable frequency pattern characterized by a quality of resonance .2, as measured by the Q factor at 3 db down, was noted in 78 of the 80 apparently normal subjects. An aberrant pattern with a Q <2, often accompanied by a lowering of the frequency content, was found in 78 of 80 postinfarction patients. We propose that the quality of resonance of S, is a measure of the degree to which the structural homogeneity of the left ventricle as a compliant contractile unit has been preserved after myocardial infarction.

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

The effects of intravenous propranolol (2 mg/kg) on myocardial ischemic injury in relation to the influence of delay in therapy on gross infarct size (GIS) were determined in 39 closed-chest anesthetized dogs in which the left anterior descending coronary artery (LAD) was occluded at a fixed distance from its origin by a balloon catheter. Precordial ECG maps. hemodynamic variables and serum CK levels were monitored for 24 hours. After 24 hours, we estimated GIS from the measured areas of ischemic discoloration in serial sections of the left ventricle (LV). In nine dogs, propranolol administration was started before LAD occlusion, in another nine 3 hours and in 10 others 6 hours after occlusion; the remainder (n = 11) served as controls. In the dogs pretreated with propranolol, the GIS (14.0 ± 4.0 g or 10.0 ± 2.0% of LV weight) was 53% smaller (p < 0.01) than in the controls (29.0 ± 2.0 g or 22.0 ± 1.0% of LV weight); those given propranolol 3 hours after occlusion had 28% smaller (p < 0.05) GIS (19.0 ± 2.0 g or 15.0 ± 2.0% LV weight) than the controls. However, GIS in the dogs receiving propranolol 6 hours after occlusion (24.0 ± 3.0 g or 19.0 ± 3.0% of LV weight) was not significantly different from that in the controls. The beneficial effect of propranolol on GIS was accompanied by corresponding directional changes in the precordial ST-segment elevation and in the rate of decline of the R-wave amplitude of the ECG. Propranolol reduced the heart rate and cardiac output for 5-6 hours in pretreated dogs; in dogs given propranolol 3 and 6 hours after occlusion, heart rate was reduced for 3-4 hours, but the cardiac output remained low for the remainder of the 24 hours. The data in these studies indicate that the beneficial effect of propranolol on GIS varies inversely with the delay in drug administration after LAD occlusion, and that no effect is apparent when propranolol infusion is begun 6 hours after occlusion.

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

Nine patients on chronic treatment with propranolol for essential hypertension for 3 months or longer were studied after abrupt discontinuation of the drug. Each patient demonstrated transient supersensitivity to the chronotropic effects of isoproterenol, beginning 2-6 days (median 4 days) after propranolol withdrawal, lasting for 3-13 days (median 6 days), with the maximum sensitivity on day 6. A significantly lower dose of isoproterenol was necessary to increase heart rate 25 beats/min on day 6 (median dose 1.2,μg, range 0.3-3.4 ug) compared with after day 14, when sensitivity had stabilized (median dose 2.3 gtg, range 1.4-7.6 Ag). Six patients had transient symptoms (headache, chest pain, palpitations and sweating) after abrupt propranolol withdrawal, coinciding with supersensitivity to isoproterenol in five. Transient increases in plasma catecholamines and blood pressures and sustained increases in heart rate occurred during the period of isoproterenol supersensitivity in most patients, and may have contributed to symptoms noted. The delayed onset and potentially long duration of μ,B-adrenergic supersensitivity after abrupt propranolol withdrawal have important clinical implications.

ISSN:0009-7322    

出版商:OVID    

年代:1979

数据来源: OVID