ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundCoronary perfusion pressure has been shown to be a significant determinant of return of spontaneous circulation from cardiac arrest during asystole and electromechanical dissociation. The addition of interposed abdominal compression to otherwise standard cardiopulmonary resuscitation (CPR) increases coronary perfusion pressure in animal and human models.Methods and ResultsAccordingly, we conducted a randomized prospective study of 143 consecutive patients experiencing cardiac arrest in a large university-affiliated teaching hospital in whom the initial arrest rhythm was asystole or electromechanical dissociation. Patients were randomized to receive either interposed abdominal compression-CPR or standard CPR. The two end points studied were return of spontaneous circulation and 24-hour survival. In addition, we studied the complications associated with interposed abdominal compression-CPR. Sixty-nine men and 74 women with a mean age of 64 years (range, 19-97 years) were studied. The overall rate of return of spontaneous circulation was 38%. Return of spontaneous circulation was significantly greater in the group receiving interposed abdominal compression-CPR compared with the group receiving standard CPR (49%o versus 28%o,p=O.Ol). At 24 hours, there was a significantly greater number of patients alive in the experimental group than in the control group (33% versus 13%,p=O.OO9). We found no complication directly related to the procedure of interposed abdominal compression in a small subset of patients who died and underwent necropsy.ConclusionsWe conclude that the addition of interposed abdominal compression may be a useful adjunct to otherwise standard CPR that can improve resuscitation outcome of patients experiencing in-hospital cardiac arrest from asystole and electromechanical dissociation.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundThe Cholesterol Lowering Atherosclerosis Study has demonstrated beneficial effect of colestipol/niacin on coronary atherosclerosis using a panel-determined global coronary change score. We now report treatment group comparisons using quantitative coronary angiographic (QCA) measures from all processable segments in 85 of 162 randomly selected baseline/2-year film pairs.Methods and ResultsTreatment benefit was established for percent stenosis for either continuous or categorical analyses with regression established regardless of the per-patient scoring procedure. In addition, treatment benefit favoring regression was established in some cases for roughness and for percent involvement, a longitudinal estimate of the percent of coronary surface involved by raised lesions. Benefit on minimum diameter was directly related to whether the segment was proximal to a graft insertion and hemodynamically related to the bypass graft. QCA correlates of panel-determined progression were increases in percent stenosis and numbers of occluded lesions in native arteries and the number of progressing lesions in bypass grafts.ConclusionsThese results demonstrate that a variety of computer measures can be used as end points in coronary angiographic therapy trials, but change in percent stenosis correlates best with visual panel assessments and best reflects the treatment benefit; when treatment effect sizes are moderate to large, the required sample size of coronary angiographic trials can be reduced when QCA is used.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundThe value of routine administration of intravenous thrombolytic agents during percutaneous transluminal coronary angioplasty (PTCA) therapy of acute myocardial infarction (MI) has not been determined. Therefore, we prospectively randomized 122 patients with evolving MI to PTCA therapy with or without adjunctive intravenous streptokinase therapy.Methods and ResultsPatients with ECG ST segment elevation who presented within 4 hours of symptom onset, had no contraindication to thrombolytic therapy, and were not in cardiogenic shock were enrolled. They were treated immediately with intravenous heparin (10,000 units) and oral aspirin (325 mg) and randomized to treatment with placebo or streptokinase (1.5 M units) administered intravenously over 30 minutes. Patients then were taken immediately to the catheterization laboratory, and those with suitable coronary anatomy underwent immediate PTCA. Subsequent clinical course, serial radionuclide ventric-ulography, and 6-month repeat angiography were analyzed. A total of 106 patients were treated with PTCA. Use of PTCA was similar for placebo (92%) and streptokinase (83%) groups. Angioplasty was successful in 95% of patients, with no difference in placebo (93%) and streptokinase (98%) groups. Serial radionuclide ventriculography demonstrated no difference in 24-hour (52 ± 12% versus 50 ± 12%) or 6-week (51 ± 12% versus 51 ± 13%) ejection fraction values for placebo and streptokinase groups, respectively. Contrast ventriculography demonstrated improvement in immediate (54 ± 12%) versus 6-month (60 ± 15%,p< 0.05) values for the overall group. No differences in 6-month values were present (58 ± 15% versus 62 ± 15%,p=NS) for placebo and streptokinase groups, respectively. Coronary angiography was performed in 75% of the 90 patients eligible for restudy. Arterial patency was 87% at 6 months, and coronary restenosis was present in 38% of patients. No differences in chronic patency or restenosis were detected for the two treatment groups. Although adjunctive intravenous streptokinase therapy did not improve outcome, it did complicate the hospital course. Hospitalization was longer (9.3 ± 5.0 versus 7.7 ± 4.4 days,p=0.046) and more costly ($25,191 ± 15,368 versus $19,643 ± 7,250,p< 0.02). Transfusion rate was higher (39%o versus 8%,p=0.0001) and need for emergency coronary bypass surgery was greater (10.3% versus 1.6%,p=0.03) for the streptokinase-treated patients.ConclusionsAdjunctive intravenous streptokinase therapy does not enhance early preservation of ventricular function, improve arterial patency rates, or lower restenosis rates after PTCA therapy of acute MI. Hospital course is longer, more expensive, and more complicated. For these reasons, PTCA therapy of acute MI should not be routinely performed with adjunctive intravenous streptokinase therapy.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundStandard mitral valve replacement (MVR) in patients with chronic mitral regurgitation consistently results in a decrease in postoperative left ventricular (LV) ejection performance. This fall in ejection performance has been attributed, at least in part, to unfavorable loading conditions imposed by the elimination of the lowimpedance pathway for LV emptying into the left atrium. In contrast to standard MVR in which the chordae tendineae are severed, however, MVR with chordal preservation (MVR-CP) does not usually decrease LV ejection performance despite similar removal of the low-impedance pathway. The purpose of the present study was to define the mechanisms responsible for this discordance in postoperative ejection performance between MVR with and without chordal preservation.Methods and ResultsEchocardiography and sphygmomanometer blood pressures were obtained in 15 patients with pure chronic mitral regurgitation before and 7-10 days after mitral valve surgery. These measurements were used to calculate ventricular volume, wall stress, and ejection fraction. Seven patients underwent MVR with chordal transection (MVR-CT), and eight patients underwent MVR-CP. MVR-CT resulted in no postoperative change in LV end-diastolic volume, a significant increase in LV end-systolic volume, a significant increase in end-systolic stress, from 89 ± 9 to 111 ± 12 g/cm2(p< 0.05), and a significant decrease in ejection fraction, from 0.60 ± 0.02 to 36 ± 0.02 (p< 0.05). In contrast, patients who underwent MVR-CP had a significant decrease in LV end-diastolic and end-systolic volumes. End-systolic wall stress actually fell from 95 ± 6 to 66 ± 6 g/cm2(p< 0.05), and ejection fraction was unchanged (0.63 ± 0.01 before and 0.61 ± 0.02 after mitral valve surgery) instead of reduced.ConclusionsMVR-CT resulted in a decrease in ejection performance caused in part by an increase in end-systolic stress, which in turn increased end-systolic volume. Conversely, MVR-CP resulted in a smaller LV size, allowing a reduced end-systolic stress and preservation of ejection performance despite closure of the low-impedance left atrial ejection pathway.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundThis study was designed to examine the expression of atrial/fetal-type myosin light chain 1 (ALC1) in human ventricles with old myocardial infarction and in control hearts.Methods and ResultsThe expression of immunoreactive (ir) ALC1 was examined in the subendocardial and subepicardial myocardium of the infarcted and the noninfarcted regions in the left ventricles with old myocardial infarction (n=12) and of the control left ventricles (n=8). For the analysis, we prepared two monoclonal antibodies, KA1 and KB1, that were specific for only ALC1 and for both ALC1 and ventricular myosin light chain 1 (VLC1), respectively. The ir-ALC1 expression ratio [ALC1/ (ALC1+VLC1), %] of the subendocardial myocardium, determined densitometrically by Western blotting with KB1, was significantly higher in the infarcted region (11.4 ± 7.3%) than in the noninfarcted region (4.7 ± 2.3%,p< 0.001) and the control ventricle (1.0 ± 1.5%,p< 0.0001). In the infarcted region, the subendocardial myocardium contained a significantly greater percentage of ir-ALCI than the subepicar-dial myocardium (5.8 ± 6.7%,p< 0.005). The ir-ALC1 expression ratio had a significant negative correlation with the value of tissue protein concentration (milligrams protein per gram wet weight). The immunohistochemical study with KA1 revealed that the surviving myocytes included in the infarcted region, especially in the ventricular aneurysm, expressed ir-ALCI strongly in comparison with those in the noninfarcted or the control ventricles.ConclusionsThese results demonstrate increased expression of ALCI and the regional differences in the failing left ventricles with old myocardial infarction. We conclude that the reexpression of ALC1 in infarcted ventricles occurs as one of the regional responses to increased load and may be a useful biochemical marker for the appearance of fetal-type myocytes.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundPrevious assessments of myocardial viability using positron emission tomography (PET) relied on demonstration of glucose metabolism in hypoperfused asynergic segments using the glucose analogue [18F]2-fluoro-2-deoxyglucose (FDG). Recently, it was shown that myocardial viability could be assessed by calculating the water-perfusable tissue index (PTI) for the asynergic region. PTI represents the proportion of the myocardium that is capable of rapid transsarcolemmal exchange of water and thus perfusable by water. The aim of the present study was to assess myocardial viability by PET using PTI in patients undergoing coronary revascularization.Methods and ResultsTwelve patients with chronic coronary artery disease and previous myocardial infarction were studied. Analysis of transmission (tissue density) and15O-labeled carbon monoxide (blood pool), and150-labeled water (myocardial blood flow [MBF]) emission PET data enabled the simultaneous quantification of MBF (ml · min−1· g perfusable tissue−1) and PTI (gram of perfusable tissue per gram of total anatomic tissue). In addition, PET imaging with FDG after 75-g oral glucose load was performed in eight patients. Preoperative echocardiography identified 33 hypocontractile and 26 control segments. Follow-up echocardiography performed 3 to 5 months later demonstrated 26 of 33 segments with improved wall motion (recovery) and seven of 33 segments without improvement (nonrecovery). MBF in the control segments (0.97 ± 0.22 ml · min−1· g perfusable tissue−1) was significantly higher (p< 0.001) than in both the recovery (0.73 ± 0.18 ml min−1g perfusable tissue−1) and the nonrecovery (0.45 ± 0.11 ml min−1· g perfusable tissue−1) segments. PTI in the recovery regions (0.99 ± 0.15) was≥0.7 in all cases and slightly less than in control regions (1.10 ± 0.15, p < 0.02). FDG uptake in these regions was 92 ± 17% (n=13) of the uptake in control segments with normal wall motion. In the nonrecovery group, PTI was 0.62 ± 0.06 (p< 0.02 versus control and recovery) and always < 0.7. In the one patient in whom a comparison with metabolic imaging was made, FDG uptake was 46% of the uptake in a reference region with normal wall motion.ConclusionsThese data showed that contractile recovery occurred only in segments where PTI was ≥0.7, suggesting that ≥70% of myocardial tissue in a given asynergic segment should be perfusable by water to enable contractile recovery. There was good agreement between the PTI and FDG methods for predicting improvements in regional wall motion after revascularization. Although further studies should be performed in a larger patient group, the preliminary results are promising and suggest that PTI may be a good predictor of contractile recovery after coronary revascularization.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundSeptal accessory atrioventricular (AV) pathways may be located in close vicinity of the His bundle-AV nodal conduction system. Attempts at surgical or electrical interruption of these pathways may therefore result in impairment of normal AV conduction. This study focuses on a subset of septal pathways with an atrial insertion located inside the triangle of Koch. In this study, they were called “midseptal”.Methods and ResultsSix patients with a midseptal accessory pathway (mean ± SD age, 40 ± 12 years; five with Wolff-Parkinson-White syndrome and one with a concealed accessory pathway) underwent attempts at ablation of their pathway using 500-kHz radiofrequency current applied to the atrial insertion of the accessory connection. Guided by the recording of accessory pathway activation potentials, the ablation catheter was positioned in all patients in an area bounded anteriorly by the tip electrode of the His bundle catheter and posteriorly by the coronary sinus ostium. All pathways were successfully ablated without the induction of complete heart block. First-degree AV conduction block occurred in one patient in whom a concealed accessory connection was located closer to the AV node than to the coronary sinus ostium.ConclusionsRadiofrequency current catheter ablation may be used effectively for midseptal accessory pathways and should be preferred in experienced centers as a safe alternative to surgical therapy.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundBefore the era of the Fontan procedure, the typical course of patients with single left ventricle (LV) consisted of heart failure and death during the second or third decade of life. Despite the advent of effective palliative therapy, ventricular dysfunction remains a significant clinical problem for these patients.Methods and ResultsTo investigate the causes of ventricular dysfunction in these patients and to determine whether Fontan-type repair reverses deterioration of LV function, the ventricular dimensions, volume, shape, wall stress, and systolic function were determined by echocardiography in 84 patients 0.2–35 years old with double-inlet single LV or tricuspid atresia. Measurements were obtained in 67 patients after palliation (arterial shunt or pulmonary artery band) and in 47 patients a median of 4.4 years after a Glenn (n=9) or a Fontan operation (n=38). Before a Fontan procedure, ventricular volumes were 2 to 3 times normal. Ventricular afterload, assessed as circumferential and meridional end-systolic wall stress, became abnormal after 2 years of age. With age, LV shape changed progressively from ellipsoidal to spherical, as indicated by the decrease in long axis: short axis ratio from normal (1.9) toward unity. Concomitantly, the ratio of circumferential to meridional end-systolic wall stress fell from 1.3 to unity, the ratio of a sphere at equilibrium. This age-related change in shape and load occurred in concert with progressive deterioration of LV systolic function and contractility. Aortic oxygen saturation, an indicator of pulmonary blood flow and therefore volume work in single-ventricle physiology, was inversely and independently correlated with contractility. In the group of patients in whom a Glenn or a Fontan operation was performed at < 10 years of age, ventricular dimensions, volumes, and wall stress diminished and LV function and contractility improved after surgery (p< 0.001). In patients undergoing surgery after 10 years of age, few had improvement of LV function after surgery. Postoperative ventricular function and contractility were inversely related to age at surgery and to aortic oxygen saturation measured before surgery.ConclusionsAlthough Fontan-type repair of single ventricle early in life is associated with reversal of the abnormal contractile mechanics associated with age and volume load, this capacity for recovery diminishes with age at surgery.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

BackgroundThe “fenestrated Fontan” (surgical baffle fenestration followed by transcatheter test occlusion and permanent closure after postoperative recovery) was adopted in an effort to reduce perioperative mortality and morbidity. This study assesses the effect of baffle fenestration on outcome.Methods and ResultsPatients having a modified Fontan operation with a cavocaval baffle and cavopulmonary anastomosis were retrospectively selected for study. Those with baffle fenestration (n=91) were compared with those without baffle fenestration (n=56) with respect to preoperative risk factors, age, anatomy, surgical date, and presence or absence of a previous bidirectional cavopulmonary anastomosis. Outcome variables were failure (death or take-down) and duration of postoperative pleural effusions and hospitalization. Survival and clinical status after hospital discharge were ascertained. The two groups did not appear to differ with respect to age or anatomic diagnosis. Patients having baffle fenestration were at significantly greater preoperative risk by univariate and multivariate analysis (p< 0.01). Operative failure was low in both groups (11% without and 7% with baffle fenestration,p=NS). Durations of pleural effusions and hospitalization were significantly shorter with baffle fenestration (p< 0.01). Neither date of surgery nor a previous bidirectional cavopulmonary anastomosis appeared to contribute to improved outcome. Patients with baffle fenestration had lower postoperative systemic venous pressure (p< 0.01). There were no late deaths. Functional status in both groups is good (82% in New York Heart Association class I).ConclusionsBaffle fenestration is associated with low mortality, significantly less pleural effusion, and significantly shorter hospitalization among high-risk patients having a modified Fontan operation.

ISSN:0009-7322    

出版商:OVID    

年代:1992

数据来源: OVID