摘要:

ABSTRACTWe have assessed the long-term results of coronary bypass surgery for angina from 1974 to 1983 in 1304 patients aged 65 years and older (group 1). Using actuarial techniques, we determined that the 5 year and 10 year survival rates for patients 65 years old or older were 81 + 2% and 65 + 3% (mean + SE), respectively. The patients aged 65 years and older were further subdivided into those aged 65 to 74 years (group la) and 75 to 84 years (group lb) and were compared with 1700 patients aged 55 to 64 years (group 2). The operative mortality in the three subgroups was 3%, 3%, and 2%, respectively (p = NS). For coronary bypass surgery, the duration of hospital stay was significantly longer (p < .0001) by a mean of 1 to 2 days for group 1 patients and the cost of hospitalization was higher by a mean of ±700 (p = .25). The cost of hospitalization was significantly higher only for group lb patients (p = .005). The 5 year survival rates for the three subgroups (la, lb, and 2) were 83 + 2%, 73 ± 5%, and 91 + 1%, respectively, and the 10 year survival rates were 66 + 3%, 65 + 7% (7 year rate for subgroup lb), and 77 2%, respectively. The lower survival rates for subgroups la and lb were significant (p < .001); however, this lower survival was only seen in men. The mortality in the general population is expected to be higher for men than for women and for patients over 65 years old (expected mortality). For men, the mortality observed in our patients was lower than the expected mortality by a similar margin for all three subgroups. This suggests that the observed higher mortality of men in subgroups la and lb is at least partly related to their older age. The reoperation rates (p = .72) and angina status at 1 to 5 years (p = .08) and 6 to 10 years (p = .68) were not significantly different among the three subgroups. We conclude the immediate and long-term results of coronary bypass surgery in patients aged 65 to 84 years are similar to those seen in a younger patient group. Therefore coronary bypass surgery should be offered to the older members of our society for the usual indications.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTWe followed 11 patients for 5 to 27 months (mean 14.9) after implantation of permanent transvenous low-energy synchronized cardioverter to evaluate both long-term reproducibility of ventricular tachycardia (VT) induction via noninvasive programmed electrical stimulation with the cardioverter and efficacy of cardioversion. Induction and termination of VT were attempted at implantation and approximately every 3 months thereafter. All patients had coronary artery disease and were receiving antiarrhythmic drug therapy (amiodarone in eight). VT cycle length, morphology, and mode of induction were reproducible on multiple occasions in nine patients; clinical VT was induced inconsistently in two patients. Multiple VT episodes in five patients had one morphology, whereas two morphologies occurred in six patients. Synchronization of the shock within the QRS complex and right ventricular effective refractory periods determined via the cardioverter remained constant over the follow-up period. VT was terminated on every occasion in nine patients and on eight of nine occasions in one patient. Tachycardia was accelerated on three of five occasions in one patient. Consistently effective cardioversion energy (0.2 to 2.0 J) increased modestly in four patients. We conclude that (1) patients with inducible monomorphic VT usually have sustained VT with similar characteristics inducible over a period of time and (2) cardioversion and sensing functions of the cardioverter remain relatively stable over time.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTWe have previously reported the use of an epicardial approach for ablation of left ventricular, free wall accessory atrioventricular pathways. The technique involves mobilization of the atrioventricular fat pad and exposure and cryoablation of the atrioventricular junction at the site of the accessory pathway on the normothermic beating heart. Here we describe our further experience with left ventricular free wall accessory pathways and right ventricular free wall accessory pathways. Our experience is based on 53 consecutive patients. There were 35 male and 18 female subjects, 6 to 52 (mean 41.4) years old. Forty-eight patients had a left ventricular free wall accessory pathway, and five had a right ventricular free wall accessory pathway. Two patients had an associated anterior septal accessory pathway. Five patients had associated cardiac abnormalities, including atrial septal defect, aortic insufficiency, mitral valve prolapse, Ebstein's anomaly, and cardiomyopathy. The accessory pathway was ablated in 52 patients who remain arrhythmia free without medication after a mean follow-up period of 12 months. The accessory pathway was permanently modified in one patient. There were no postoperative complications. This epicardial approach can be performed with normothermic cardiopulmonary bypass or without bypass. It does not require cross-clamping of the aorta, allowing a greater margin of safety when this is required for concomitant procedures.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTA beneficial effect of verapamil on left ventricular relaxation has been reported in patients with hypertrophic cardiomyopathy. The effect of 0.1 mg/kg intravenous verapamil on left ventricular relaxation and diastolic mechanics was studied in 10 patients with hypertrophic cardiomyopathy and 13 patients with aortic stenosis. M mode echocardiograms and left ventricular high-fidelity pressure measurements were obtained simultaneously in patients at rest and 10 to 15 min after verapamil. The time constant of left ventricular pressure decay (T; in msec) and the pressure intercept (PB; in mm Hg) were calculated from left ventricular pressure and negative dP/dt during isovolumetric relaxation with the use of a linear regression analysis. Left ventricular early and mean diastolic filling rates as well as diastolic pressure-diameter relationships before and after verapamil were determined from simultaneous echocardiographic and pressure measurements. After verapamil heart rate, left ventricular peak systolic pressure, and maximum and minimum dP/dt remained unchanged in both groups. Left ventricular end-diastolic pressure increased significantly from 15 to 17 mm Hg (p < .02) in patients with aortic stenosis but did not change in those with hypertrophic cardiomyopathy. However, the time constant T decreased significantly from 79 to 60 msec (p < .001) in patients with hypertrophic cardiomyopathy but increased significantly from 53 to 68 msec (p < .025) in those with aortic stenosis. Parallel to the decrease in time constant, early (5.3 vs 7.3 cm/sec, p < .05) and mean (3.0 vs 4.3 cm/sec, p < .06) diastolic lengthening rate increased in patients with hypertrophic cardiomyopathy after verapamil. In contrast, early (7.7 vs 7.6 cm/sec, p = NS) and mean (4.3 vs 4.2 cm/sec, p = NS) diastolic lengthening rate remained unchanged in patients with aortic stenosis. The diastolic pressure-diameter relationship did not change in either group after verapamil. Cycle efficiency of the left ventricular pressure-diameter loop was significantly decreased in patients with hypertrophic cardiomyopathy when compared with that in those with aortic stenosis (71% vs 80%; p < .01), but improved significantly from 71% to 77% (p < .02) in patients with hypertrophic cardiomyopathy and remained unchanged in those with aortic stenosis (80% vs 80%) after verapamil. We conclude that verapamil improves left ventricular relaxation in patients with hypertrophic cardiomyopathy but delays relaxation in those with aortic stenosis. The absence of changes in the hemodynamic determinants of left ventricular relaxation suggests an intrinsic although opposite effect of verapamil on the myocardium in patients with primary and secondary myocardial hypertrophy. The beneficial effect of verapamil in those with hypertrophic cardiomyopathy seems to be related to improved relaxation and diastolic filling rather than to changes in passive elastic chamber properties. This improvement in relaxation and diastolic filling can be explained by an increase in cycle efficiency with a decrease in left ventricular asynchrony. A beneficial effect of verapamil is not observed in patients with secondary myocardial hypertrophy due to aortic stenosis.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThe influence of long-term treatment with amiodarone on exercise hemodynamics and on left ventricular relaxation was studied prospectively in patients with hypertrophic cardiomyopathy. Rest-exercise hemodynamics (n = 9) and echocardiographic relaxation indexes (isovolumic relaxation time, dPW/dt) (n = 11) were measured in control conditions and after 5 weeks of oral amiodarone treatment (600 mg daily first week, 400 mg daily second week, 200 mg daily afterwards). Long-term amiodarone treatment in patients at rest caused a significant drop in heart rate from 80 ± 1 1 to 75 ± 11 beats/min (p < .05), a rise in mean pulmonary artery pressure from 19 + 7 to 25 ± 10 mm Hg (p < .02), and a rise in mean pulmonary capillary wedge pressure from 11 ± 4 to 17 ± 8 mm Hg (p < .05). Systemic arterial pressure, cardiac output, and systemic vascular resistance remained unaltered. Exercise tolerance assessed by serial supine bicycle stress testing was reduced in six of nine patients. Amiodarone treatment caused a significant rise in pulmonary capillary wedge pressure from 22 ± 8 to 37 ± 9 mm Hg (p < .001) at the highest identical workloads and from 26 ± 10 to 37 9 (p < .005) at maximal symptom-limited workloads. Similarly, mean pulmonary artery pressure rose from 37 + 15 to 51 ± 18 mm Hg (p < .01) at highest identical workloads and from 42 ± 19 to 51 ± 18 mm Hg (p < .01) at maximal symptom-limited workloads. There were no significant differences at maximal exercise level in heart rate, systemic arterial pressure, cardiac output, or exercise factor. Echocardiographic studies performed before and during long-term amiodarone treatment revealed no change in isovolumic relaxation time, end-diastolic or end-systolic posterior wall thickness, and peak posterior wall thinning rate. A negative inotropic action of amiodarone could explain the worsened rest and exercise hemodynamics observed during long-term treatment of patients with hypertrophic cardiomyopathy. Echocardiographic relaxation indexes remained unaltered despite the elevated left ventricular filling pressures. This finding could suggest a deleterious effect of amiodarone on myocardial inactivation, possibly similar in mechanism to the depressed myocardial inactivation observed in hypothyroidism.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTCatheter balloon inflation performed during percutaneous transluminal coronary angioplasty (PTCA) results in temporary interruption of coronary blood flow and subsequent myocardial ischemia. This produces transient but profound regional left ventricular dysfunction. In an effort to mitigate this inflation-related dysfunction, oxygenated Fluosol DA 20%, a perfluorochemical oxygen transport fluid, was infused distal to the balloon through the central lumen of the dilating catheter during balloon inflation. Regional wall motion during PTCA was assessed by simultaneous continuous two-dimensional echocardiography and was quantified by computer analysis. During control inflations accompanied by no intracoronary infusion or by transcatheter infusion of Ringer's lactate solution or nonoxygenated Fluosol DA 20%, there was profound regional left ventricular dysfunction with a greater than 90% decrease in regional contraction. In contrast, regional contraction during transcatheter infusion of oxygenated Fluosol DA 20% remained at normal levels throughout balloon inflation. Distal infusion of Fluosol DA 20% during balloon inflation is a useful adjunct to PTCA, allowing longer inflation times and perhaps permitting PTCA to be performed safely in patients with significant myocardium at ischemic risk or with limited left ventricular reserve for whom the procedure is currently believed to be too hazardous.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThe final translesional pressure gradient measured during coronary angioplasty correlates with immediate angiographic and clinical results. Whether the pressure gradient is of value in predicting late clinical outcome has not been determined. We therefore obtained complete follow-up information on 159 patients with single-vessel disease who underwent successful coronary angioplasty. Mean follow-up time was 15 ± 10 months. The occurrence of repeat angioplasty, coronary bypass surgery, recurrent anginal chest pain, or a positive postangioplasty stress test were considered clinical events indicative of late failure. Of the variables age, gender, initial and final translesional pressure gradient, extent of initial and final arterial narrowing, site of dilatation, type of balloon catheter used, number of inflations, and maximal inflation pressure, only the final translesional pressure gradient was predictive of late failure when analyzed by multivariate techniques. Thus, the final translesional pressure gradient is of value in predicting both immediate and late outcome after coronary angioplasty.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTTo determine whether myocardial reperfusion can be detected promptly by changes in profiles of isoforms of MM-creatine kinase (CK) in plasma, coronary occlusion was induced in 30 conscious dogs and reperfusion was initiated after 1, 2, 3, or 4 hr in 21. The myocardial isoform of MM-CK, MMA, was quantified in serial plasma samples by chromatofocusing. Before coronary occlusion, MMA comprised 13 ± 7% (SD) of the total CK activity in plasma. The percentage of MMA (MMA%) was elevated before reperfusion, but increased markedly and consistently to a peak of 52 ± 13% (n = 21) between 30 min and 1 hr after the time of onset of reperfusion. The rate of increase in MMA% was significantly faster with reperfusion at 1 hr (1.44 ± 0.42% min'), 2 hr (1.28 ± 0.45% min-1), or 3 hr (1.02 ± 0.27% min-1) (p < .001), but not with reperfusion at 4 hr (0.48 ± 0.34% min-') compared with the rate in nonreperfused control dogs (0.29 0.09% min-1). Furthermore, the rate of increase in MMA% was neither influenced by peak total CK activity (r = − .1) nor dependent on infarct size measured histochemically 24 hr after coronary occlusion (r = − .003). The time from coronary occlusion to the peak ofMMA% was reduced by reperfusion at 1 to 3 hr compared with control, but this index was not identified as rapidly as the rate of increase in MMA%. Accordingly, characterization of the rate of increase in MMA% in plasma when reperfusion occurs early after the onset of myocardial infarction permits prompt, reliable, and noninvasive detection of myocardial reperfusion.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThe study of venodilator tolerance to nitroglycerin has been complicated by reflex compensation and by problems in analyzing venous tone in the presence of multiple determinants of venous pressure. We assessed venous tone as total effective vascular compliance (TEVC) undei autonomic blockade in six dogs, in the nontolerant state, and during a 5 day infusion of nitroglycerin (1.5, μg/kg/min). Under long-term treatment, baseline TEVC was unaffected and the nitroglycerin dose-response relationship for TEVC was shifted to greater than 10-fold higher doses, whereas baseline mean arterial pressure (MAP) was lowered by 17 ± 3 mm Hg without any shift in nitroglycerin responsiveness. This lowering of MAP was observed only after autonomic blockade. In six additional dogs instrumented with aortic flow probes, nitroglycerin (1.5, μg/kg/min) induced a 15 ± 1% decline in peripheral vascular resistance (PVR) under autonomic blockade, but with reflexes intact these dogs showed no change in PVR and a 21 ± 10% increase in norepinephrine release rate. We conclude that modest long-term exposure to nitroglycerin results in tolerance to its venodilating effects, whereas arteriolar action is maintained. This tolerance-induced shift in action from venous toward arteriolar dilation is normally masked by compensatory reflexes.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

ABSTRACTThe effect of pretreatment with heparin on lysis of arterial thrombi by tissue-type plasminogen activator (rt-PA) was studied in 19 dogs. Copper coil-induced carotid artery thrombi were weighed, inserted into the femoral arteries, and exposed to a 15 min infusion of rt-PA at 10, μg/kg/min either with (n = 6 thrombi) or without pretreatment with a 200 unit/kg bolus of heparin (n = 6 thrombi). The infusion of rt-PA without pretreatment reduced the thrombus weight by 27.6 ± 7.4%, while infusion of rt-PA with pretreatment reduced it by 79.1 ± 12.3% (p < .0001). To test the hypothesis that heparin enhanced thrombolysis by preventing continued incorporation of new fibrin into the thrombus during thrombolysis we repeated the experiments using pretreatment with 8 U/kg of ancrod, which rapidly depletes fibrinogen. Pretreatment with ancrod (n = 6 thrombi) depleted fibrinogen and enhanced the lytic effect of rt-PA to a similar degree as pretreatment with heparin, resulting in a 67.6 ± 12.3% (NS) decrease in thrombus weight. We conclude that heparin significantly enhances the thrombolytic effect of rt-PA, probably by preventing new fibrin formation and its incorporation into the thrombus during lysis.

ISSN:0009-7322    

出版商:OVID    

年代:1986

数据来源: OVID