ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

In patients with chronic coronary artery disease and left ventricular dysfunction, the distinction between ventricular dysfunction arising from myocardial fibrosis and ischemic, but viable, myocardium has important clinical implications. By positron emission tomography (PET), enhanced fluorine-18-labeled fluorodeoxyglucose (FDG) uptake in myocardial segments with impaired function and reduced blood flow is evidence of myocardial viability. Reinjection of thallium-201 at rest immediately after stress-redistribution imaging may also provide evidence of myocardial viability by demonstrating thallium uptake in regions with apparently “irreversible” defects. To compare these two methods, we studied 16 patients with chronic coronary artery disease and left ventricular dysfunction (ejection fraction, 27 ± 9%), all of whom had irreversible defects on standard exercise-redistribution thallium single-photon emission computed tomography (SPECT) imaging. Thallium was reinjected immediately after the redistribution study, and SPECT images were reacquired. The patients also underwent PET imaging with FDG and oxygen-15-labeled water. A total of 432 myocardial segments were analyzed from comparable transaxial tomograms, of which 166 (38%) had irreversible thallium defects on redistribution images before reinjection. FDG uptake was demonstrated in 121 (73%) of these irreversible defects. Irreversible defects were then subgrouped according to the degree of thallium activity, relative to peak activity in normal regions. Irreversible defects with only mild (60—85% of peak activity) or moderate (50–59% of peak) reductionin thallium activity were considered viable on the basis of FDG uptakein 91% and 84% of these segments, respectively. In contrast, inirreversible defects with severe reduction in thallium activity (< 50% of peak), FDG uptake was present in 51% of segments. In such severe defects, an identical number of segments (51%) demonstrated enhanced uptake of thallium after reinjection. In these severe “irreversible” defects, data on myocardial viability were concordant by the two techniques in 88% of segments, with 45% identified as viable and 43% identified as scar on both PET and thallium reinjection studies. These observations suggest that thallium imaging can be used to identify viable myocardium in patients with chronic coronary artery disease and left ventricular dysfunction. Most irreversible defects with only mild or moderate reduction in thallium activity represent viable myocardium as confirmed by FDG uptake. In myocardial regions with severeirreversible thallium defects on standard exercise-redistribution thallium imaging, thallium reinjection identifies as viable or nonviable, with few exceptions, the same regions as does PET imaging with FDG.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The Caerphilly Collaborative Heart Disease Study is based on a large cohort of men (2,398) aged 49–66 years at the time of study. Platelet aggregation induced by collagen, thrombin, and ADP was measured in fasting blood samples and was related to prevalent angina, past myocardial infarction, and electrocardiographic evidence of ischemic heart disease. A number of subjects had taken aspirin, other nonsteroidal anti-inflammatory drugs, or other drugs affecting platelet aggregation 7 days before blood sample collection; after the exclusion of these subjects, data were available for 1,811 men. No relations were demonstrated with angina, but significant relations were shown between past myocardial infarctions and electrocardiographic evidence of ischemia and ADP-induced aggregation (both primary and secondary) and between electrocardiographic evidence of ischemia and thrombin-induced aggregation. The strongest relation indicated more than a twofold increase in the odds of a past myocardial infarction in subjects of the highest fifth of ADP-induced primary platelet aggregation compared with the lowest fifth. No significant relations were detected with collagen-induced aggregation. Accounting for a number of possible confounding factors had a relatively small impact on the relations between platelet aggregation and ischemic heart disease. Other evidence, including the well-established effect of aspirin on reducing the incidence of ischemic heart disease, indicates that the relations we describe are unlikely to be simply an effect of IHD on platelets.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Mexican-American men experience reduced cardiovascular mortality compared with non- Hispanic white men. There is no corresponding ethnic difference in cardiovascular mortality in women. The difference in men could result either from a lower incidence of cardiovascular disease or a lower case fatality rate among Mexican-Americans. Although the incidence of cardiovascular disease in Mexican-Americans is unknown, we have collected data on prevalence of myocardial infarction in 5,148 individuals examined in the San Antonio Heart Study, a population-based survey of cardiovascular disease conducted between 1979 and 1988 in Mexican-Americans and non-Hispanic whites aged 25—64 years. Myocardial infarction was assessed by Minnesota-coded electrocardiograms and by a self-reported history of a physiciandiagnosed heart attack. For both end points, the age-adjusted prevalence of myocardial infarction was lower in Mexican-American men than in non-Hispanic white men. After adjustment for age and diabetes status (present/absent), the odds of a myocardial infarction, as defined by either criterion, was approximately one third lower in Mexican-American men than in non-Hispanic white men (p= 0.06). In women, the prevalence of both myocardial infarction end points was slightly higher in Mexican-Americans than in non-Hispanic whites, although neither of these differences was significant. Although the ethnic differences in prevalence in this study were not statistically significant, their pattern parallels the pattern in the mortality due to cardiovascular diseases. Therefore, the results support the hypothesis that the reduced cardiovascular mortality rate observed in Mexican-American men reflects a lower incidence of myocardial infarction rather than a reduced case fatality rate because the latter would result in a higher prevalence.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The Multicenter Diltiazem Postinfarction Trial (MDPIT) reported no consistent diltiazem effect on new or worsened congestive heart failure (CHF) during 12—52 months' follow-up after acute myocardial infarction. This was puzzling in light of the observation that patients with findings suggesting left ventricular dysfunction (LVD) at baseline on diltiazem had more cardiac events (cardiac mortality or recurrent nonfatal infarction) than such patients on placebo. We hypothesized that diltiazem increased the frequency of late CHF as well as of cardiac events, but only in patients predisposed by LVD. Using the same characterizing variables as the primary MDPIT analysis, we found that patients with pulmonary congestion, anterolateral Q wave infarction, or reduced ejection fraction (EF) at baseline were more likely to have CHF during follow-up than those without these markers of LVD. CHF was particularly frequent in the patients with LVI) who were randomized to diltiazem. Among those with a baseline EF of less than 0.40, late CHF appeared in 12% (39/326) receiving placebo and 21% (61/297) receiving diltiazem (p= 0.004). Life table analysis in patients with an EF of less than 0.40 confirmed more frequent late CHF in those taking diltiazem (p= 0.0017). In addition, the diltiazem-associated rise in the frequency of late CHF was progressively greater with increasingly severe decrements in baseline EF. This diltiazem effect was absent in patients with pulmonary congestion at baseline but an EF of 0.40 or more, suggesting a unique association between diltiazem-related late CHF and systolic LVD. Diltiazemassociated enhancement ofCHF in patients with an EF of less than 0.40 was evident among those who took concomitant, B-blockers and among those who did not. We conclude that postinfarction patients with reduced EF are at particular risk for subsequent CHF when treated with diltiazem. This problem, along with the greater occurrence of cardiac events in patients with LVD, indicates a need for caution when giving diltiazem to patients with postinfarction LVD.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Transesophageal echocardiography allows the evaluation of proximal coronary artery anatomy and coronary blood flow velocity (CBFV). To assess the potential of transesophageal echocardiography in evaluating CBFV and its variations induced by coronary-active drugs, we studied 15 patients by high-quality pulsed wave Doppler recordings of CBFV. In these patients, transesophageal Doppler evaluation of CBFV was performed before, 2 minutes after cessation of dipyridamole infusion (0.56 mg/kg in 4 minutes), and 2 minutes after aminophylline infusion (240 mg injected 4 minutes after cessation of dipyridamole infusion). The following CBFV parameters were evaluated at each of the three steps of the study protocol: maximal and mean diastolic velocities and maximal and mean systolic velocities. Furthermore, the following indexes of coronary flow reserve were evaluated: the ratio between maximal diastolic velocity recorded after and before dipyridamole administration and the ratio between mean diastolic velocity recorded after and before dipyridamole administration. Nine of the 15 patients had a normal left anterior descending coronary artery (group A), whereas the remaining six had significant (.75%) stenosis (group B). In group A patients, all CBFV parameters increased significantly during dipyridamole infusion and returned to near baseline values after aminophylline infusion. In group B patients, on the other hand, none of the CBFV parameters increased after dipyridamole infusion. Dipyridamole/baseline maximal diastolic velocity and mean diastolic velocity ratios were, respectively, 3.22 ± 0.96 and 3.04 ± 0.88 in group A and 1.46 ± f-0.45 (p< 0.01 versus group A) and 1.48 ± 0.49 (p< 0.01 versus group A) in group B patients. We conclude that transesophageal Doppler echocardiography evaluation of CBFV is feasible and makes possible the evaluation of the changes induced by coronary-active drugs. This new approach has potential in assessing coronary blood flow reserve.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

This study was conducted in 46 patients with cardiac thrombi, 15 patients with atrial myxomas, and 32 patients with other cardiac or paracardiac tumors. Diagnoses were subsequently proven by surgery, autopsy, computed tomography, magnetic resonance imaging, or angiography in all patients. All patients underwent precordial and transesophageal two-dimensional echocardiography to assess the various mass detection rates. Atrial myxomas and predominantly left-sided cardiac tumors were identified by both echocardiographic techniques with comparable detection rates. Left ventricular apical thrombi were detected more frequently by precordial echocardiography. In contrast, transesophageal echocardiography was superior in visualizing left atrial appendage thrombi, small and flat thrombi in the left atrial cavity, thrombi and tumors in the superior vena cava, and masses attached to the right heart and the descending thoracic aorta. These data indicate that transesophageal echocardiography leads to a clinically relevant improvement of the diagnostic potential in patients in whom cardiac masses are suspected or have to be excluded in order to ensure the safety of clinical procedures.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Combined echocardiography and Doppler color flow mapping from transthoracic imaging windows has become the standard method for the noninvasive assessment of valvular regurgitation. This study compared regurgitant jet areas by Doppler color flow imaging derived from the newer transesophageal approach with measurements obtained from conventional transthoracic apical views. Maximal regurgitant jet area determinations and an overall visual estimate of lesion severity were obtained from 42 patients who underwent color flow examination by both techniques. Seventy-three regurgitant lesions were visualized by transesophageal flow imaging: 34 mitral, 22 aortic, and 17 tricuspid jets. Transthoracic studies in the same patients revealed fewer regurgitant lesions for each valve: 20 mitral, 16 aortic, and 12 tricuspid (p= 0.0009). A comparison of maximal jet areas determined by transesophageal and transthoracic studies showed a good overall correlation (r= 0.85, SEE=2.8 cm2) and a systematic overestimation by the transesophageal technique (TEE=0.96 TTX + 2.7). For the subgroup with mitral insufficiency, valve lesions visualized by both techniques were larger by the transesophageal approach (n= 18, 6.0 versus 3.6 cm2,p=0.008). Semiquantitative visual grading of individual valve lesions by two independent observers revealed a higher grade of regurgitation with more jets classified as mild (38 versus 25), moderate (18 versus 13), and severe (17 versus 10) by esophageal imaging than by transthoracic imaging. Thus, transesophageal color flow mapping techniques yield a higher prevalence of valvular regurgitation than do transthoracic techniques in the same patients. Jet area and the overall estimate of regurgitant lesion severity were also greater by transesophageal color Doppler imaging compared with standard transthoracic imaging. As a result, currently used standards for predicting severity of regurgitation by Doppler color flow mapping must be reexamined when the esophageal window is used.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

To assess the effect of bypass surgery on outcome from unstable angina, 468 patients were randomized to medical treatment (237 patients) or surgery plus medical treatment (231 patients) and have been followed for comparison of survival, cardiac end points, and quality of life; the latter end point is discussed in the present report. Data were available at 3 and 5 years for 80% and 82% of patients in the medical group, respectively, and 77% and 80% of patients in the surgery group, respectively. At 3 months after randomization to therapy, 79.8% of patients in the surgery group reported subjective improvement, compared with 58% of the medical group, 12.6% of the surgery group reported no change compared with 24.5% of the medical group, and 5.5% of the surgery group reported worsening compared with 24.5% of the medical group (p< 0.01 byX2). Similar data were found for chest pain status, and the benefit to the surgery group remained statistically significant through 5 years of follow-up. Crossover rate to surgery was 43% by 5 years. Treadmill duration was increased in the surgery group compared with the medical group (6.5 ± 0.25 versus 5.3 ± 0.25 minutes at 6 months, p < 0.01), and a significant difference was again demonstrated at 3 and 5 years. A trend toward decreased recurrence of unstable angina was present in the surgery group at 1 year (six of 168 [3.6%] versus 13 of 187 [6.9%1] in the medical group, p =0.158), but the two groups were similar at 3 and 5 years. Patients in the surgery group used less nitroglycerin and propranolol than their medical counterparts at 1 and 3 years of follow-up (p< 0.01), but by 5 years these variables were similar. Working status never differed between the two groups. Thus, bypass surgery produces immediate improvement in quality-of-life variables, and the effects in some end points were shown to persist for 5 years after surgery. Other beneficial effects of surgery diminish by 5 years.

ISSN:0009-7322    

出版商:OVID    

年代:1991

数据来源: OVID