ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundHypertrophic cardiomyopathy (HCM) is diagnosed clinically by the presence of left ventricular hypertrophy (LVH). However, LVH is absent in a significant number of genotype-positive patients. Because myocyte dysfunction and disarray are the primary abnormalities in HCM, we reasoned that tissue Doppler imaging could identify contraction and relaxation abnormalities, irrespective of hypertrophy, in a transgenic rabbit model of human HCM.Methods and ResultsM-mode, 2D, Doppler echocardiography and tissue Doppler imaging were performed in nontransgenic (n=24), wild-type &bgr;-myosin heavy chain-arginine403(n=14), and mutant &bgr;-myosin heavy chain-glutamic acid403(n=24) transgenic rabbits. Mean septal thicknesses were 2.0±0.3, 2.0±0.25, and 2.75±0.3 mm in the 3 groups, respectively (P=0.001). LVH was absent in 9 of the 24 mutant rabbits. Left ventricular dimensions, systolic function, heart rate, mitral inflow velocities, and time intervals were similar in the groups. However, the difference between atrial reversal and transmitral A wave duration was increased in the mutant rabbits (P<0.001). More importantly, systolic and early diastolic tissue Doppler velocities were significantly lower in all mutant rabbits (7.45±2.2 versus 10.8±2.3 cm/s in nontransgenic and 9.0±0.76 cm/s in wild-type;P<0.001), including the 9 without LVH. A systolic velocity <8.5 cm/s had an 86% sensitivity and 100% specificity in identifying the mutant transgenic rabbits.ConclusionsMyocardial contraction and relaxation were reduced in the mutant &bgr;-myosin heavy chain-glutamic acid403transgenic rabbit model of human HCM, irrespective of the presence or absence of LVH. In addition, tissue Doppler imaging is more sensitive than conventional echocardiography for HCM screening.

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundIn sedentary humans endothelium-dependent vasodilation is impaired with advancing age contributing to their increased cardiovascular risk, whereas endurance-trained adults demonstrate lower age-related risk. We determined the influence of regular aerobic exercise on the age-related decline in endothelium-dependent vasodilation.Methods and ResultsIn a cross-sectional study, 68 healthy men 22 to 35 or 50 to 76 years of age who were either sedentary or endurance exercise–trained were studied. Forearm blood flow (FBF) responses to intra-arterial infusions of acetylcholine and sodium nitroprusside were measured by strain-gauge plethysmography. Among the sedentary men, the maximum FBF response to acetylcholine was 25% lower in the middle aged and older compared with the young group (P<0.01). In contrast, there was no age-related difference in the vasodilatory response to acetylcholine among the endurance-trained men. FBF at the highest acetylcholine dose was almost identical in the middle aged and older (17.3±1.3 mL/100 mL tissue per minute) and young (17.7±1.4 mL/100 mL tissue per minute) endurance-trained groups. There were no differences in the FBF responses to sodium nitroprusside among the sedentary and endurance- trained groups. In an exercise intervention study, 13 previously sedentary middle aged and older healthy men completed a 3-month, home-based aerobic exercise intervention (primarily walking). After the exercise intervention, acetylcholine-mediated vasodilation increased ≈30% (P<0.01) to levels similar to those in young adults and middle aged and older endurance-trained men.ConclusionsOur results indicate that regular aerobic exercise can prevent the age-associated loss in endothelium-dependent vasodilation and restore levels in previously sedentary middle aged and older healthy men. This may represent an important mechanism by which regular aerobic exercise lowers the risk of cardiovascular disease in this population.

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundWe have studied the relations between physical activity, types of physical activity, and changes in physical activity and all-cause mortality in men with established coronary heart disease (CHD).Methods and ResultsIn 1992, 12 to 14 years after the initial screening (Q1) of 7735 men 40 to 59 years of age from general practices in 24 British towns, 5934 (91% of available survivors, mean age 63 years) provided further information on physical activity (Q92) and were followed up for 5 years; 963 had a physician’s diagnosis of CHD (myocardial infarction or angina). After exclusions, there were 772 men with established CHD, 131 of whom died of all causes. The lowest risks for all-cause and cardiovascular mortality were seen in light and moderate activity groups (adjusted relative risk compared with inactive/occasionally active: light, 0.42 (0.25, 0.71); moderate, 0.47 (0.24, 0.92); and moderately vigorous/vigorous, 0.63 (0.39, 1.03). Recreational activity of ≥4 hours per weekend, moderate or heavy gardening, and regular walking (>40 min/d) were all associated with a significant reduction in all-cause mortality. Nonsporting activity was more beneficial than sporting activities. Men sedentary at Q1 who began at least light activity by Q92 showed lower mortality rates on follow-up than those who remained sedentary ( relative risk 0.58, 95% CI 0.33 to 1.03;P=0.06).ConclusionsLight or moderate activity in men with established CHD is associated with a significantly lower risk of all-cause mortality. Regular walking and moderate or heavy gardening were sufficient to achieve this benefit.

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundThis prospective multicenter randomized clinical trial was designed to evaluate the long-term angiographic and clinical outcomes of elective treatment with the GR-II stent compared with the Palmaz-Schatz (PS) stent in patients with coronary stenoses.Methods and ResultsSeven hundred fifty-five patients with myocardial ischemia and de novo native coronary stenoses in 3- to 4-mm vessels were randomly assigned to the PS (375 patients) or the GR-II stent (380 patients). The primary end point was 12-month target lesion revascularization (TLR)-free survival. Angiography was performed at baseline and at follow-up in the first 300 consecutive patients to assess the frequency of angiographic restenosis. Procedure success was 98.5% for the GR-II stent and 99.4% for the PS stent (P=0.19). At 30 days, patients assigned to the GR-II stent had a higher stent thrombosis rate (3.9% versus 0.3% for PS stent,P<0.001) and TLR rate (3.9% versus 0.5% for PS stent,P<0.001). The GR-II group had a higher follow-up restenosis frequency (47.3% versus 20.6% for the PS group,P<0.001) and a lower 12-month TLR-free survival rate (71.7% versus 83.9% for the PS group,P<0.001). Multivariate logistic regression analysis identified a smaller final stent minimal lumen diameter (odds ratio [OR] 2.49, 95% CI 1.56 to 3.98;P<0.001), diabetes mellitus (OR 2.14, 95% CI 1.42 to 3.22;P<0.001), and use of the GR-II stent (OR 1.78, 95% CI 1.20 to 2.64;P<0.01) as independent determinants of 12-month TLR.ConclusionsOn the basis of these long-term follow-up data, we conclude that use of the GR-II stent should be limited to the acute treatment of abrupt or threatened closure after failed conventional balloon angioplasty procedures.

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundPTCA is performed primarily to improve health-related quality of life (HRQOL) in patients with symptomatic coronary artery disease. In patients undergoing PTCA, smoking has been shown to increase risks of late myocardial infarction and death. Whether smoking also affects HRQOL after PTCA is currently unknown.Methods and ResultsWe examined the relation between smoking status and HRQOL among 1432 patients who underwent PTCA as part of 2 multicenter clinical trials. HRQOL was assessed with the use of the Medical Outcomes Study SF-36 questionnaire. Patients were classified as smokers (n=301), quitters (n=141), or nonsmokers (n=990) on the basis of their smoking status at the time of their index procedure and during the first year of follow-up. For the overall population, HRQOL improved significantly after PTCA for all scales except general health perception, with improvements ranging from 5.5 points for mental health to 23.2 points for role-physical functioning. After adjustment for baseline characteristics and initial HRQOL, nonsmokers had gains at 6 months that were larger than those of smokers for all health domains: physical function (15.4 versus 10.4 points), role-physical (24.5 versus 13.9), pain (18.4 versus 13.3), general health perception (1.7 versus −4.5), vitality (11.0 versus 4.7), social function (12.8 versus 3.5), role-emotional (13.5 versus 6.7), and mental health (6.8 versus 0.8;P<0.02 for all comparisons). Quitters had 6-month HRQOL improvements that were greater than those in smokers for all domains as well. Findings were similar at 1 year.ConclusionsQuality-of-life benefits of PTCA are diminished by continued smoking. Efforts to promote smoking cessation at the time of PTCA may substantially improve the health outcomes of these procedures.

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

BackgroundLittle information exists concerning practice patterns between Canada and the United States in the management of myocardial infarction (MI) patients without ST-segment elevation and unstable angina.Methods and ResultsWe examined the practice patterns and 1-year outcomes of 2250 US and 922 Canadian patients without ST-elevation acute coronary syndromes in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) IIb trial. The US hospitals more commonly had on-site facilities for angiography and revascularization. These procedures were performed more often and sooner in the United States than Canada, whereas Canadian patients were more likely to undergo noninvasive stress testing. The length of initial hospital stay was 1 day longer for Canadian than US patients. Recurrent and refractory ischemia was more common in Canada. One-year mortality was comparable between the 2 countries. However, at 6 months, even after baseline differences were accounted for, the (re)MI rate was significantly higher in Canadian than US patients with unstable angina (8.8% versus 5.8%,P=0.039), as was the composite rate of death or (re)MI (13.1% versus 9.1%,P=0.016).ConclusionsOne-year mortality was comparable between Canada and the United States in both MI and unstable angina cohorts despite higher intervention rates in the United States. However, outcomes at 6 months among patients with unstable angina differed. Whereas more frequent coronary interventions were not associated with reduced recurrent MI or death among MI patients without ST elevation, they may favorably affect outcomes in patients with unstable angina.

ISSN:0009-7322    

出版商:OVID    

年代:2000

数据来源: OVID