ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Forty-eight patients with a posteroseptal accessory atrioventricular (AV) connection underwent catheter ablation of the accessory AV connection with 200–400 J shocks delivered by a standard defibrillator. Cathodal shocks were delivered through the proximal pair of electrodes of a 6F quadripolar electrode catheter positioned in the coronary sinus such that the proximal electrodes straddled the ostium (12 patients) or the third electrode from the tip was at the ostium (36 patients). A 16-cm patch electrode positioned on the back or anterior chest served as the anode. Two to 4 shocks were delivered (total, 635±198 J, mean±SD). The catheter ablation procedure was clinically successful in eliminating symptomatic tachycardias in 32 of 48 patients (67%) during a mean follow-up of 26±19 months. A long-term follow-up electrophysiology study was performed in 27 of the 32 patients who had a successful clinical outcome, and this showed that conduction through the accessory AV connection was completely absent in 25 patients and present but impaired in two patients. The success rate was significantly higher in patients with a concealed accessory AV connection (13 of 13, 100%) than in patients with manifest preexcitation (19 of 35, 54%;p< 0.001). Among the 12 patients in whom the proximal electrodes of the ablation catheter straddled the ostium of the coronary sinus, one patient developed cardiac tamponade requiring needle pericardiocentesis; there were no instances of cardiac tamponade among the 36 patients in whom the third electrode from the tip was at the ostium of the coronary sinus. Other complications were AV block requiring a permanent pacemaker and transient atrial tachycardia in one patient each and an asymptomatic pericardial effusion in three patients. In conclusion, with the catheter ablation technique described in this study, a successful clinical outcome may be achieved in approximately two thirds of patients who have a posteroseptal accessory AV connection, and the risk of serious complications is low. This technique is particularly well suited to patients with a concealed posteroseptal accessory AV connection, in whom the success rate is higher than in patients with manifest preexcitation.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

Left main coronary artery disease (i.e., ≥50% stenosis) was found in 1,477 of 20,137 patients in the Coronary Artery Surgery Study (CASS) registry. Of these patients, 53 (3.6%) were asymptomatic. Asymptomatic and symptomatic patients were similar in regard to 1) severity of left main coronary artery stenosis (67% vs. 70%), 2) extent of proximal coronary artery disease (no differences in number of or severity of proximal stenoses), 3) left ventricular end-diastolic pressure (13 mm Hg vs. 14 mm Hg), 4) left ventricular wall motion score (9.1 vs. 8.7), and 5) number of coronary artery segments with greater than 70% stenosis (4.4 vs. 4.8). Among the asymptomatic patients, 47% received medical and 49% received surgical treatment. In the symptomatic group, 20% received medical and 78% received surgical therapy. The survival rate 5 years after surgery for treatment of left main coronary artery stenosis was 84% for the symptomatic patients and 88% for the asymptomatic patients (p= NS). Medical management of left main coronary artery disease produced a 5-year survival rate of 57% for asymptomatic patients and 58% for symptomatic patients. Within the asymptomatic subgroup, 88% of those surgically treated survived 5 years, whereas only 57% of those medically treated survived 5 years (p= 0.02). Thus, for CASS patients with left main coronary artery disease, the percentage of those that were asymptomatic is low (3.6%); asymptomatic and symptomatic patients with left main coronary artery disease had no significant difference in severity of left main coronary artery stenosis, extent of overall coronary artery disease, or left ventricular function. Finally, in this nonrandomized series, survival in patients with asymptomatic left main coronary artery disease was significantly improved with surgery compared with medical management.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

A micromethod adapted for automated determinations was used to measure basal plasma levels of homocyst(e)ine [H(e)]. These levels included the sum of free and bound forms of homocysteine, its disulfide oxidation product, homocystine, and the homocysteine-cysteinemixed disulfide. Two groups of subjects were studied: apparently healthy individuals (n= 103) and patients with peripheral arterial occlusive disease (PAOD) (n= 47). Because age in PAOD patients was higher than in control subjects, the control subjects were subdivided into younger and older groups (aged 60 years or less and more than 60 years, respectively). The H(e) levels in the younger groups were 11.18±3.58 (mean±SD, expressed as homocysteine) and 8.58±2.82 nmol/ml in men and women, respectively; in the older groups, the levels were 10.74±2.16 and 9.04±2.16 nmol/ml in men and women, respectively. There was a positive correlation of H(e) levels with age in the younger control women (r= 0.373;p< 0.02); no significant correlations were present in the other three control groups. Levels of H(e) in PAOD patients (15.44±5.76 and 17.04±8.26 nmol/ml in men and women, respectively) were significantly higher than those indicated above in the older controls. Next, the PAOD patients were assigned to two subgroups: 1) those with normal levels of H(e) (within two standard deviations of the mean of the control values) and 2) those with elevated levels of H(e). Age, cholesterolemia, and the prevalence of smoking and diabetes were similar in both subgroups. These results suggest that elevated plasma H(e) is an independent risk factor for arterial occlusive disease.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The efficacy, morbidity, and 1-year follow-up of balloon aortic valvuloplasty in patients with low ejection fraction (< 40%) were studied on a consecutive series of 55 patients (mean age, 77 years) treated from September 1985 to February 1987. Because of their age (20 patients >80 years old), poor left ventricular function, and associated diseases, 45 patients were definitely not surgical candidates. Balloon dilatation with 15–23-mm diameter balloon catheters decreased the transvalvular gradient from 66±24 to 28±14 mm Hg (p< 0.001) and increased the valve area from 0.47±0.15 to 0.83±0.27 cm2(p< 0.001). Immediately after dilatation, ejection fraction mildly increased from 29±7% to 34±9% (p< 0.001) in 38 patients who had undergone a second left ventricular angiogram after dilatation. No significant change in the degree of aortic regurgitation was found after the procedure. Three patients died in hospital (femoral arterial complications in two, septicemia in one). Immediate clinical improvement was noted in 80% of the patients. During the follow-up (mean, 11 months), 22 patients died (heart failure in 15 patients, sudden death in five patients, myocardial infarction in one patient, cancer in one patient). Thirty patients survived, 21 with persistent clinical improvement. Repeat cardiac catheterization was performed at 6 months in 20 patients, of whom eight had recurrence of symptoms. Nine patients had restenosis: their hemodynamic indexes had returned to prevalvuloplasty values. In the 11 patients with no restenosis, aortic valve area was 0.73±0.14 versus 0.48±0.13 cm2before dilatation, and the ejection fraction had increased from 39±10% to 52±10% (p< 0.05). From this series, which represents our early experience in balloon aortic valvuloplasty, we conclude that when the increase in valve area is maintained for several months, clinical improvement in functional status is substantial and that ejection fraction may increase to almost normal levels in some patients. One-year follow-up shows a high secondary mortality rate that can be related to the severity of left ventricular impairment and to either insufficient valve dilatation or subsequent restenosis.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

To evaluate the electrophysiologic changes in the cardiac conduction system that occur during percutaneous mitral or aortic balloon valvotomy, we prospectively studied the conduction system in 19 patients (10 mitral, 8 aortic, and 1 both) undergoing this procedure. A His bundle electrogram was recorded in all patients, and when sinus rhythm was present, the atrioventricular (AV) node effective refractory period was measured. Holter monitoring was performed during and for 24 hours after the procedure. Follow-up electrocardiograms (ECG) were available in 11 patients 2.3±1.5 months after the procedure. The AV node effective refractory period before (276±86 msec) and after valvotomy (298±85 msec) were not significantly different. The maximum His-Purkinje conduction time (HV interval) observed during valvotomy (66±20 msec) was significantly longer (p< 0.01) than that measured before (57±10 msec) or after (60±18 msec) valvotomy. The mean HV intervals before and after valvotomy were not significantly different. The mean QRS complex duration increased from 95±28 to 112±28 msec during valvotomy and remained significantly prolonged (109±26 msec) 24 hours after procedure (p< 0.01). A new intraventricular conduction defect (QRS complex duration >100 msec) or bundle branch block occurred in five of 13 patients who had normal QRS duration before the procedure. The change in HV interval did not correlate with the change in QRS complex duration. In four patients, the newly acquired intraventricular conduction defect was still present on follow-up ECG tracing. Complete heart block was not observed in any patient. Age, New York Heart Association functional classification, coronary artery disease, the valve dilated, annular area, effective balloon dilating area, change in valve area, and use of digoxin did not correlate with the change in HV interval or QRS complex duration by multiple regression analysis. Analysis of ECG data in a much larger group of 207 patients undergoing percutaneous mitral and aortic balloon valvotomy showed an 18% incidence of new-onset intraventricular conduction defect after valvotomy.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

To identify factors responsible for the decline of plasma tissue-type plasminogen activator (t-PA)-specific activity that we have observed after infusions of the activator and to define the potential usefulness of selected variants of t-PA in obviating them in patients with infarction, serial plasma samples from patients (n=4) and rabbits (n= 15) given t-PA were assayed for total t-PA antigen, t-PA activity, and free as opposed to type-i plasminogen activator inhibitor (PAI-1)-complexed t-PA. In patients, attenuation of t-PA specific activity after infusions was evident with concentrations of total t-PA antigen that were as much as sevenfold greater than pretreatment values (62 compared with 9 ng/ml). Attenuation of t-PA activity corresponded with the disappearance of free t-PA from plasma and was associated with persistence of complexes of t-PA with PAI-1. In normal rabbits (n=4) given wild-type t-PA by bolus injection, PAI-1 activity was 4±1 arbitrary units/ml. Attenuation of t-PA activity was not evident until minutes after injection at a time when total plasma t-PA antigen concentration was as low 13±8 ng/ml. Under these conditions, plasma t-PA was composed predominantly of free t-PA. In rabbits (n= 5) given lipopolysaccharide to increase plasma PAI-1 activity to 193±84 arbitrary units/ml, the specific activity of t-PA was attenuated as early as 15 minutes after injection at a time when total t-PA antigen concentration was as high as 164±79 ng/ml. As was the case with samples from patients, attenuation was associated with the disappearance of free t-PA and the persistence of complexes of t-PA with PAI-1. A genetically engineered variant of t-PA with comparable specific activity and a comparable rate constant of association with PAI-1 but designed to persist in the circulation manifested prolonged clearance from plasma of normal rabbits (n=3) (t1/2=24.6±1.6 minutes compared with an a phase t112 of 1.9 minutes for wild-type t-PA). The variant lacked the epidermal growth factor and kringle one domains and contained duplicated kringle two domain. In contrast to the case with wild-type t-PA when rabbits were given lipopolysaccharide to augment plasma PAI-1, attenuation of activity of the variant of t- PA was not evident until 60 minutes after injection at a time when the total plasma t-PA antigen concentration was 403±64 ng/ml (n=3). Thus, t-PA activity paralleled the concentration of free rather than total t-PA that is dependent upon clearance of free and complexed t-PA from the circulation and upon interactions with plasma protease inhibitors including PAI-1.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

The density of β-adrenergic receptors is reduced in crude membranes prepared from failing human myocardium. We used quantitative autoradiography of radioligand binding sites in intact tissue slices to determine whether the total tissue content of receptors is reduced and to characterize the transmural distribution of receptors in cardiac myocytes and the coronary vasculature in hearts obtained from nine cardiac transplant patients with severe congestive failure. Binding of [125Iodo]cyanopindolol to transmural slices of human myocardium was rapid, saturable, stereoselective, and displaceable by agonists and antagonists with an appropriate rank order of potency. Binding isotherms in four normal and nine failing ventricles showed a significant reduction in the total tissue content of β-receptors in failing myocardium (38.3±2.0 fmol/mg protein) compared with normal tissue (52.4±1.7 fmol/mg protein,p= 0.038). In the normal ventricles, the greatest receptor density was observed autoradiographically in myocytic regions of the subendocardium. Receptor density of the coronary arterioles was approximately 70% of that in adjacent myocytic regions. The density of binding sites in both myocytic regions and arterioles was diminished in all regions of the failing ventricles, but down-regulation was due primarily to a selective reduction of, β-receptors of subendocardial myocytes (63±5% of subepicardial receptor density vs. 115±6% in controls,p< 0.0001). These observations indicate that down-regulation occurs nonuniformly in the transmural distribution and thus is likely not related simply to elevated circulating catecholamine levels.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

We examined the influence of alterations in preload on pulsed Doppler indexes of left ventricular diastolic function in 50 patients including 12 without cardiovascular disease, 29 with coronary artery disease, and nine with critical aortic stenosis. Micromanometer left ventricular pressure was recorded simultaneously with pulsed Doppler echocardiography of left ventricular inflow and M-mode echocardiography of left ventricular diameter. Chamber stilfness constants, kdand kv, were obtained from the diastolic pressure-diameter and pressure-volume relations, respectively. Relaxation was measured by the isovolumic relaxation time constants, TLand TD, derived from the exponential left ventricular pressure decay and maximum negative dP/dt. In 41 patients after nitroglycerin treatment, left ventricular end-diastolic pressure decreased from 18±5 to 13±4 mm Hg (p< 0.001). The ratio of peak early to peak atrial filling velocities and time-velocity integral ratios decreased from 1.08±0.57 to 0.90±0.42 (p< 0.001) and from 1.77±0.95 to 1.41±0.71 (p< 0.001), respectively. The peak early filling velocity and timevelocity integral decreased from 56.1±15.7 to 49.9±14.5 cm/sec (p< 0.001) and from 7.9±2.7 to 6.8±2.8 cm (p< 0.001), respectively. Relaxation (TL, TD, and maximum negative dP/dt) and chamber stiffness (kdand kv) were not impaired after nitroglycerin administration. In 48 patients after ventriculography, left ventricular end-diastolic pressure increased from 18±6 to 22±8 mm Hg (p< 0.001). The peak early and peak atrial filling velocities increased from 57.4±15.2 to 68.3±19.7 cm/sec (p< 0.001) and from 61.0±22.7 to 69.4±23.2 cm/sec (p< 0.01), respectively. As a result, the ratio of peak early to peak atrial filling velocity was unchanged. However, in the aortic stenosis group, the ratio of peak early to peak atrial filling velocity increased from 0.95±0.64 to 1.10±0.72 (p< 0.02). Relaxation and chamber stiffness were unchanged. Thus, a reduction or increase in preload may induce a diastolic filling pattern that mimics or masks diastolic dysfunction, respectively. Preload conditions need to be accounted for when the status of diastolic function is extrapolated from the pulsed Doppler mitral inflow velocity profile.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID

摘要:

To investigate the effect of Kawasaki syndrome on myocardial function, as well as the influence of high-dose intravenous γ-globulin therapy on resolution of functional abnormalities, we studied 98 patients with Kawasaki syndrome during five time intervals from onset of illness: 1) 10 days or less, 2) 11–31 days, 3) 1–3 months, 4) 3–12 months, and 5) 1–3 years. Normal controls included 48 children under age 8 years, without known cardiovascular disease. Using two-dimensional directed M-mode echocardiograms, we obtained chamber dimensions, fractional shortening, rate-corrected velocity of shortening (Vcfc) adjusted for end-systolic wall stress, and early diastolic function parameters that included adjusted peak rates of left ventricular dimension change, wall thinning, and their respective timing. Left ventricular systolic and diastolic dimensions were larger (bothp< 0.01) in patients than in normal subjects in period 1. Stress-adjusted Vcfc was much lower in patients in the 3 months after disease onset; by period 5, contractility was comparable in patients and normal subjects. Adjusted indexes of early diastolic function did not differ significantly between patients and normal subjects. To investigate the effect of γ-globulin, we analyzed data on 47 patients prospectively randomized to therapy with aspirin alone (n= 19, 40%) or to aspirin plus γ-globulin, 400 mg/kg/day for 4 consecutive days (n= 28, 60%). In period 1, before treatment, the two groups had mean fractional shortening and stress-adjusted Vcfc comparable to each other but much lower than those of normal subjects (p≤ 0.001). Patients treated with aspirin alone continued to have diminished fractional shortening and Vcfc compared with normal subjects in periods 2, 3, and 4 (allp≤ 0.05). In contrast, fractional shortening and Vcfc in γ-globulin-treated patients in these periods were comparable to those of normal subjects. By period 5, no difference was detected in systolic function or contractility between either treatment group and normal subjects. We conclude that early abnormalities of left ventricular contractility and myocardial function, as assessed by echocardiography, generally resolve by 1–3 years after disease onset and that recovery is accelerated by administration of IVGG in the acute phase.

ISSN:0009-7322    

出版商:OVID    

年代:1989

数据来源: OVID