ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Aspirin has been convincingly shown to reduce (1) stroke and death in men with transient ischemic attacks (it may possibly be beneficial to women also), (2) myocardial infarction and death in patients with unstable angina, (3) thromboembolic complications associated with artificial heart valves in patients receiving oral anticoagulants (although gastrointestinal bleeding is prohibitive with this combination), and (4) thrombotic occlusion of silicone rubber arteriovenous cannulae in uremic patients undergoing hemodialysis. In addition, aspirin may possibly decrease occlusion of saphenous vein aortocoronary grafts and venous thrombosis in men after hip replacement, although these reports require confirmation. Aspirin is ineffective in the secondary prevention of stroke and has unproven benefit in the secondary prevention of myocardial infarction. Dipyridamole in combination with oral anticoagulation decreases the thromboembolic complications associated with mechanical heart valves. The combination of aspirin and dipyridamole prevents both early and late occlusion of saphenous vein aortocoronary bypass grafts and protects renal function in patients with membranoproliferative glomerulonephritis. The relative importance of combining aspirin and dipyridamole compared with either agent used singly remains to be established. Sulfinpyrazone reduces the thrombotic occlusion of arteriovenous cannulae and early occlusion of saphenous vein aortocoronary grafts. The reported benefit in the secondary prevention of myocardial infarction is controversial.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We studied the effect of drive train duration on human right bundle branch refractoriness. Seven patients with a QRS duration of 0.10 sec or less and no preexcitation had functional right bundle branch block induced reproducibly with premature atrial stimulation. Refractoriness of the right bundle branch was defined as the longest H1H2 interval resulting in right bundle branch block and was determined in each patient at a constant pacing cycle length but at five to seven different atrial drive train durations varying from four to 99 complexes. In all seven patients, right bundle branch refractoriness decreased with increasing drive train duration (mean 15 msec). One-third of this decrease (5.0 msec) occurred between drive train durations of four and eight complexes, and close to two-thirds (9.3 msec) occurred between drive train durations of eight and 64 complexes. Very little further decrease (0.7 msec) occurred between 64 and 99 complexes. We conclude that right bundle branch refractoriness shortens progressively as the preceding drive train duration increases. This phenomenon may in part explain the disappearance of functional right bundle branch block during supraventricular tachycardia after a variable number of complexes without a change in cycle length of tachycardia.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

To study the prevention of occlusion of aortocoronary-artery bypass grafts, we conducted a prospective, randomized, double-blind trial comparing long-term administration of dipyridamole (begun 2 days before operation) plus aspirin (begun 7 hr after operation) with placebo in 407 patients. Results at 1 month and at 1 year showed a reduction in the rate of graft occlusion in patients receiving dipyridamole and aspirin. On the basis of our clinical trial and our experimental studies in dogs and pigs, we describe four consecutive phases of aortocoronary artery bypass vein-graft disease: (1) an early postoperative phase of platelet thrombotic occlusion, which' is significantly prevented by platelet inhibitor therapy when started in the perioperative period; in addition, occlusion rates are presently decreasing, perhaps related to better surgical and technical experience; (2) an intermediate phase of platelet-related intimal hyperplasia, within the first postoperative year, which is not prevented with platelet inhibitor therapy; (3) a late phase of occlusion, toward the end of the first postoperative year, in which intimal hyperplasia or complicating platelet thrombi superimposed on the intimal hyperplasia may contribute to occlusion; platelet inhibitor therapy is of significant benefit in the prevention of this thrombotic type of occlusion; (4) a phase of atherosclerotic disease, after the first postoperative year, in which the role of platelets and of platelet inhibitor therapy is under investigation.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Coronary angiography has proved beyond doubt that complete coronary occlusion is rule in the very early hours of infarction. The 60% to 80% rate of coronary recanalization after thrombolytic therapy has proved that thrombosis is a major component of the occlusion at the time when the procedure is performed a few hours after the onset of symptoms. However, the trigger for coronary thrombosis and the causes of failure of thrombolytic therapy are still a matter of speculation. The relatively rare occurrence of acute coronary occlusion in the life of an individual with even severe coronary disease can be explained on the basis of the necessity of either (1) extremely powerful isolated stimuli, which only occurs rarely, or (2) the casual simultaneous presence in one coronary arterial segment of multiple unfavorable events, such as plaque fissuring, enhanced reactivity of coronary smooth muscle to constrictor stimuli and displacement of the thrombotic-thrombolytic equilibrium toward thrombosis. Coronary artery constriction possibly caused by vasonconstrictor substances released by thrombus, represents the potential element of a vicious cycle causing persistent coronary occlusion and reocclusion when reflow occurs with thrombolysis.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

There is evidence that aspirin is partially effective in the prophylaxis of various vasoocclusive disorders. This article reviews pharmacologic opportunities for improvement over and above the therapeutic effect of aspirin. It is concluded that several rational possibilities merit consideration, in particular, the use of combinations of drugs that affect the thrombotic process at different points. ABSTRACT There is evidence that aspirin is partially effective in the prophylaxis of various vasoocclusive disorders. This article reviews pharmacologic opportunities for improvement over and above the therapeutic effect of aspirin. It is concluded that several rational possibilities merit consideration, in particular, the use of combinations of drugs that affect the thrombotic process at different points. Such strategies will ultimately require validation by clinical trial.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

To determine the evolution of amyloid heart disease, 28 patients with familial amyloid polyneuropathy (FAP) were studied by echocardiography. The incidence and degree of the abnormalities were correlated with the neurologic disabilities, duration of the illness, and age in cross-sectional studies. Serial studies were performed in 12 patients, who were followed for a mean of 27.7 months. At the initial examinations, left ventricular diastolic function was reduced in six patients, while systolic function was preserved in eight. On follow-up there occurred significant increases in ventricular septal wall thickness (from 10.7 + 3.1 to 13.1 + 3.2 mm; p < .01) and posterior wall thickness (from 11.8 2.5 to 13.5 + 2.3 mm; p < .01), and reductions in the E-F slope of the mitral valve (from 64.4 18.8 to 43.9 ± 1 1.0 mm/sec; p < .01), percent fractional shortening (from 36.5 + 9.4% to 28.8 + 8.2%; p < .02), and left ventricular internal diastolic dimension (from 46.2 + 6.1 to 42.4 ± 6.2 mm; p < .001). At the final examinations, marked ventricular hypertrophy was found in three patients, reduced left ventricular diastolic function in all, impaired systolic function in nine, and decreased left ventricular internal dimension in three. In addition, highly refractile myocardial echoes had appeared in two patients, pericardial effusion in three, and valve thickening in two. We conclude that amyloid heart disease in patients with FAP develops slowly but progressively.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Although past reports have identified a variety of prognostic factors in patients with severe chronic heart failure, previous studies have not evaluated the interaction of prognostic variables and drug treatment. We analyzed the association of 30 clinical, hemodynamic, and biochemical variables with survival in 203 consecutive patients with severe heart failure; all variables were assessed just before initiation of treatment with a variety of vasodilator drugs, and all patients were subsequently followed for 6 to 94 months. By regression analysis, pretreatment serum sodium concentration was the most powerful predictor of cardiovascular mortality, with hyponatremic patients having a substantially shorter median survival than did patients with a normal serum sodium concentration (164 vs 373 days, p = .006). The unfavorable prognosis for hyponatremic patients appeared to be related to the marked elevation of plasma renin activity that we noted in these individuals (10.0 + 2.0 ng/ml/hr), since hyponatremic patients fared significantly better when treated with angiotensin converting-enzyme inhibitors than when treated with vasodilator drugs that did not interfere with angiotensin LI biosynthesis (median survival 232 vs 108 days, p = .003). In contrast, there was no selective benefit of converting-enzyme inhibition on the survival of patients with a normal serum sodium concentration, in whom plasma renin activity was low (1.9 + 0.3 ng/ml/hr). This interaction between serum sodium concentration, drug treatment, and long-term outcome suggests that the renin-angiotensin system may exert a deleterious effect on the survival of some patients with chronic heart failure, which can be antagonized by converting enzyme inhibition, and provides a clinical counterpart for the similar prognostic role that has been postulated for angiotensin II in experimental preparations of heart failure.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Twenty-five healthy adults underwent subcostal-view, four-chamber two-dimensional echocardiographic examination while upright at rest and at the peak of maximal bicycle exercise. The purpose of the study was to determine whether the variability in regional left ventricular endocardial motion, previously demonstrated to be present at rest, persisted at peak exercise. The rest and exercise end-diastolic and end-systolic endocardial contours were visually identified, digitized, and divided into 32 radial segments after realignment by the computer. At rest there was similar percent segmental area reduction for the septum (segments 1 to 12) (54 + 4%, mean + 1 SD), apex (segments 13 to 20) (67 + 3%), and lateral wall (segments 21 to 32) (67 + 8%). At peak exercise the percent area reduction increased significantly: septum 84 ± 5%, apex 88 2%, lateral wall 83 + 6% (p < .001 compared with rest for all areas). However, there was considerable variability in percent area reduction between different radial segments in the same individual. At rest the difference between minimal and maximal percent area reduction within the same individual was 49 ± 17 percentage units (range 21 to 83) and that at peak exercise was 32 ± 17 percentage units (range 0 to 66). It is concluded that, because the range of standard deviation of normal endocardial motion and the degree of variability between radial segments in the same healthy individual are significant, qualitatively determined “hypokinesis,” as commonly assessed clinically, may be a normal event. However, segmental akinesis or dyskinesis, which occurred rarely at rest and never at peak exercise, must be considered abnormal events.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Left ventricular pulsus alternans (LVPA), a rhythmic beat to beat variation in left ventricular systolic pressure and outflow gradient, was noted in 35 of 200 patients with hypertrophic cardiomyopathy undergoing hemodynamic study. LVPA was not associated with significant systemic pulsus alternans nor right ventricular pulsus alternans. All patients with LVPA had severe outflow gradients at rest or during provocation. Of 61 patients with severe basal outflow gradients (greater than 80 mm Hg), 12 demonstrated LVPA at rest. Eight of these patients underwent ventricular septal myotomy-myectomy; all had successful abolition of basal outflow gradient. Of the seven of these eight patients who underwent postoperative hemodynamic study and who were in sinus rhythm, none demonstrated LVPA. Eleven of 60 patients with basal outflow gradients ranging from 10 to 70 mm Hg demonstrated LVPA during maneuvers provocative for outflow gradients (mean gradient 90 + 37 mm Hg). Two of these patients underwent ventricular septal myotomy-myectomy; neither had a gradient nor LVPA during provocation postoperatively. Twelve additional patients with basal outflow gradients ranging from 0 to 115 mm Hg had LVPA after ectopic beats, generally occurring during maneuvers provocative for outflow gradients, associated with severe outflow gradients (mean gradient 130 + 39 mm Hg) during the postextrasystolic beat. None of the 41 patients without an outflow gradient, basal or during provocation, was found to have LVPA. Thus LVPA is commonly seen in patients with hypertrophic cardiomyopathy and severe left ventricular outflow gradients and may represent inadequate left ventricular contractile function in the presence of high left ventricular systolic pressures.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID