Abstract:
BACKGROUND:Repeated brief episodes of myocardial ischemia performed by mechanical clamping of a coronary artery "precondition" the heart and reduce infarct size after a subsequent sustained ischemia. It is not known, however, whether spontaneous episodes of transient ischemia caused by formation of platelet thrombi, which may occur in unstable angina, have a similar cardioprotective effect. METHODS AND RESULTS:Therefore, our objective was to determine whether brief spontaneous thrombotic episodes of ischemia/reperfusion could limit infarct size and preserve contractile function following 60 minutes (protocol 1) or 90 minutes (protocol 2) of sustained ischemia and 4-4.5 hours of reperfusion in the canine model. Before the sustained coronary occlusion, dogs underwent a 30-minute "treatment" period consisting of: no intervention (control group), four repeated episodes of 3-minute mechanical occlusion plus 5-minute reperfusion (preconditioned group), or coronary artery stenosis and endothelial injury, resulting in a mean of four spontaneous episodes of cyclic flow variations (CFV group) caused by formation and dislodgment of platelet thrombi. In protocol 1 (60-minute sustained ischemia plus 4.5-hour reperfusion), infarct size was significantly smaller in both the preconditioned and CFV groups compared with controls (3.5 +/- 1.4%,* 3.4 +/- 2.1%,* and 9.9 +/- 2.7% of the myocardium at risk, respectively; *p less than 0.05 versus control). In contrast, neither preconditioning nor CFV preserved contractile function: Segment shortening during sustained occlusion was equally depressed at -15% to -20% of baseline values among the three groups and equally stunned at +12% to +18% of baseline during the 4.5 hours of reflow. In protocol 2 (90-minute sustained ischemia plus 4-hour reperfusion), only CFV continued to exert a cardioprotective effect: Infarct size averaged 15.0 +/- 4.1%, 7.4 +/- 2.5%,* and 16.5 +/- 4.4% of the region at risk in the preconditioned, CFV, and control groups, respectively (*p less than 0.05 versus control). Contractile function, however, was similar among all three groups both during 90 minutes of sustained occlusion and throughout 4 hours of reperfusion. CONCLUSIONS:We therefore conclude that repeated coronary thrombus formation preconditions the ischemic myocardium: In fact, in contrast to mechanical preconditioning, cardioprotection provided by CFV persisted following 90 minutes of sustained coronary occlusion. However, preconditioning by thrombotic or mechanical occlusion neither preserved myocardial contractile function during sustained coronary occlusion nor prevented stunning after reperfusion. These data raise the possibility that clinical episodes of unstable angina prior to acute myocardial infarction may precondition the ischemic myocardium.
journal_name
Circulationjournal_title
Circulationauthors
Ovize M,Kloner RA,Hale SL,Przyklenk Kdoi
10.1161/01.cir.85.2.779subject
Has Abstractpub_date
1992-02-01 00:00:00pages
779-89issue
2eissn
0009-7322issn
1524-4539journal_volume
85pub_type
杂志文章相关文献
CIRCULATION文献大全abstract:BACKGROUND:-Recent studies have suggested that testosterone has a protective effect in the arterial vascular system. However, little is known about the molecular aspects of the mechanism(s) involved in these processes. The aim of the present study was to investigate the effect of testosterone on neointimal plaque devel...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.103.10.1382
更新日期:2001-03-13 00:00:00
abstract:BACKGROUND:Re-stenting of in-stent restenosis (ISR) improves acute angiographic results. Methods and Results- Volumetric intravascular ultrasound analysis was performed in 70 ISR lesions that received either placebo (n=36) or (192)Ir radiation (n=34). ISR lesions treated by re-stenting were divided into 3 groups: old s...
journal_title:Circulation
pub_type: 临床试验,杂志文章
doi:10.1161/01.cir.0000018949.39445.40
更新日期:2002-05-28 00:00:00
abstract:BACKGROUND:We have reported that myocardial ischemia increases nitric oxide (NO) production. Several lines of evidence suggest that NO reduces myocardial contraction. Therefore, we tested whether endogenous NO decreases the inotropic response of the ischemic myocardium and whether endogenous NO is beneficial in the met...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.93.2.356
更新日期:1996-01-15 00:00:00
abstract::Calcification of valvular bioprostheses in children is a major problem that has stimulated extensive research in our laboratory. In previous reports, we have shown that the rate of calcification could be reduced by decreasing the phosphate content in the tissue or by blocking calcification binding sites with Mg++ and/...
journal_title:Circulation
pub_type: 杂志文章
doi:
更新日期:1984-09-01 00:00:00
abstract:BACKGROUND:The alpha1-adrenergic receptors (alpha1-ARs) play a key role in cardiovascular homeostasis. However, the functional role of alpha1-AR subtypes in vivo is still unclear. The aim of this study was to evaluate the cardiovascular influences of alpha1b-AR. METHODS AND RESULTS:In transgenic mice lacking alpha1-AR...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.0000012750.08480.55
更新日期:2002-04-09 00:00:00
abstract:BACKGROUND:Impaired endothelium-dependent vasodilation is an early sign of atherosclerosis in hypercholesterolemic patients. We hypothesized that lipid-lowering therapy can improve endothelial function and that this effect is mainly mediated by increased bioavailability of nitric oxide (NO). METHODS AND RESULTS:In a r...
journal_title:Circulation
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1161/01.cir.98.3.211
更新日期:1998-07-21 00:00:00
abstract:BACKGROUND:We recently demonstrated that phospholipase C (PLC)-delta1 activity in cultured skin fibroblasts obtained from patients with coronary spastic angina (CSA) is enhanced. We tested the hypothesis that structural abnormality in PLC-delta1 isoform is a cause of the enhanced activity. METHODS AND RESULTS:Sequence...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.0000014613.36469.3f
更新日期:2002-04-30 00:00:00
abstract:BACKGROUND:Myocardial infarction with nonobstructive coronary arteries (MINOCA) is a puzzling clinical entity with no previous evaluation of the literature. This systematic review aims to (1) quantify the prevalence, risk factors, and 12-month prognosis in patients with MINOCA, and (2) evaluate potential pathophysiolog...
journal_title:Circulation
pub_type: 杂志文章,meta分析,评审
doi:10.1161/CIRCULATIONAHA.114.011201
更新日期:2015-03-10 00:00:00
abstract::The continuity equation suggests that a ratio of velocities at two different cardiac valves is inversely proportional to the ratio of cross-sectional areas of the valves. To determine whether a ratio of mitral/aortic valve orifice velocities is useful in determining aortic valve area in patients with aortic stenosis, ...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.73.5.964
更新日期:1986-05-01 00:00:00
abstract::Dual antiplatelet therapy with aspirin and a thienopyridine has been shown to reduce cardiac events after coronary stenting. However, many patients and healthcare providers prematurely discontinue dual antiplatelet therapy, which greatly increases the risk of stent thrombosis, myocardial infarction, and death. This ad...
journal_title:Circulation
pub_type: 杂志文章,实务指引
doi:10.1161/CIRCULATIONAHA.106.180944
更新日期:2007-02-13 00:00:00
abstract:BACKGROUND:The development of selective atrial antiarrhythmic agents is a current strategy for suppression of atrial fibrillation (AF). METHODS AND RESULTS:Whole-cell patch clamp techniques were used to evaluate inactivation of peak sodium channel current (I(Na)) in myocytes isolated from canine atria and ventricles. ...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/CIRCULATIONAHA.107.704890
更新日期:2007-09-25 00:00:00
abstract:BACKGROUND:Alterations in myocardial function and systemic vascular tone are well documented in congestive heart failure (CHF), but little information is available on the effects of CHF on pulmonary vessels. We examined the mechanisms of tone regulation of canine pulmonary arteries during pacing-induced CHF. METHODS A...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.87.5.1722
更新日期:1993-05-01 00:00:00
abstract::Few data are available regarding the effects of exercise training upon cardiac structure and performance in man. We evaluated the echograms of 24 normals before (PRE) and after (POST) 11 weeks of endurance exercise training. Conditioning consisted of a walk-jog-run protocol at 70% maximal heart rate for one hour four ...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.57.2.237
更新日期:1978-02-01 00:00:00
abstract::To evaluate the severity of heart failure, cardiopulmonary exercise testing was performed in 99 normal subjects and in 382 patients with cardiac disease. Anaerobic threshold, peak oxygen uptake, and the ratio of increase in oxygen uptake to work-rate increment were determined by ventilatory and gas exchange measuremen...
journal_title:Circulation
pub_type: 杂志文章
doi:
更新日期:1990-01-01 00:00:00
abstract:BACKGROUND:The role of intracellular calcium (Ca(i)) in defibrillation and vulnerability is unclear. METHODS AND RESULTS:We simultaneously mapped epicardial membrane potential and Ca(i) during shock on T-wave episodes (n=104) and attempted defibrillation episodes (n=173) in 17 Langendorff-perfused rabbit ventricles. U...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/CIRCULATIONAHA.106.630509
更新日期:2006-12-12 00:00:00
abstract:BACKGROUND:Sympathetic activation and respiratory abnormalities may each be implicated in the pathophysiology of congestive heart failure (CHF). Chemoreflexes are an important mechanism regulating both sympathetic drive and breathing. We therefore tested the hypothesis that chemoreflex function is altered in CHF. METH...
journal_title:Circulation
pub_type: 临床试验,杂志文章
doi:10.1161/01.cir.100.3.262
更新日期:1999-07-20 00:00:00
abstract:BACKGROUND:Endogenous adenosine can protect the overloaded heart against the development of hypertrophy and heart failure, but the contribution of A(1) receptors (A(1)R) and A(3) receptors (A(3)R) is not known. METHODS AND RESULTS:To test the hypothesis that A(1)R and A(3)R can protect the heart against systolic overl...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/CIRCULATIONAHA.108.788307
更新日期:2008-10-21 00:00:00
abstract:BACKGROUND:Endothelial integrity is essential for maintaining vascular homeostasis, and endothelial denudation results in neointimal thickening. Balloon-expandable endovascular stents provide a luminal scaffolding within atherosclerotic arteries with minimal direct contact between balloon and endothelium. We wondered w...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.94.11.2909
更新日期:1996-12-01 00:00:00
abstract:BACKGROUND:Despite their increasing clinical use and recent evidence that growth hormone (GH) and insulin-like growth factor-1 (IGF-1) target the heart, there has been no systematic investigation of the effects of GH and IGF-1 on the cardiovascular system. METHODS AND RESULTS:Sixty normal but growing adult female rats...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.93.4.800
更新日期:1996-02-15 00:00:00
abstract:BACKGROUND:Cardiac vagal predominance increases the RR interval and RR high-frequency (HF) variability during non-rapid eye movement (non-REM) sleep (stages I through IV) in young subjects. Aging suppresses deep sleep, but effects of age-related changes in sleep architecture on RR are unknown. Whether mechanical effect...
journal_title:Circulation
pub_type: 临床试验,杂志文章
doi:10.1161/01.cir.103.1.84
更新日期:2001-01-02 00:00:00
abstract::Experience with percutaneous transluminal coronary angioplasty (PTCA) of multiple vessels was reviewed to assess short-term outcome and long-term results. PTCA of multiple vessels was performed in 100 of the initial 500 patients (20%) who underwent PTCA at the Medical College of Virginia between July 1979 and August 1...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.72.6.1314
更新日期:1985-12-01 00:00:00
abstract:BACKGROUND:Patients with prior atherosclerosis in 1 or more vascular territories (coronary, cerebrovascular, or peripheral arterial) who present with acute coronary syndromes have high cardiovascular risk and may benefit significantly from evidence-based therapies, yet whether these are used consistently is unknown. M...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/CIRCULATIONAHA.109.877092
更新日期:2009-08-18 00:00:00
abstract:BACKGROUND:Epidemiological studies aimed at correlating coronary heart disease (CHD) with serum ferritin levels have thus far yielded inconsistent results. We hypothesized that a labile iron component associated with non-transferrin-bound iron (NTBI) that appears in individuals with overt or cryptic iron overload might...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/CIRCULATIONAHA.105.545350
更新日期:2006-04-25 00:00:00
abstract:BACKGROUND:Normal mammalian mitral leaflets have regional heterogeneity of biochemical composition, collagen fiber orientation, and geometric deformation. How leaflet shape and regional geometry are affected in dilated cardiomyopathy is unknown. METHODS AND RESULTS:Nine sheep had 8 radio-opaque markers affixed to the ...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/CIRCULATIONAHA.105.000554
更新日期:2006-07-04 00:00:00
abstract::Iron catalysis is involved in oxygen-derived free radical generation and subsequent lipid peroxidation, which have been reported to occur during cardiopulmonary bypass in humans. We assessed the effects of the iron chelator deferoxamine on the susceptibility of circulating low density lipoproteins (LDLs) to induced pe...
journal_title:Circulation
pub_type: 临床试验,杂志文章,随机对照试验
doi:
更新日期:1990-11-01 00:00:00
abstract:BACKGROUND:To assess the reliability of pediatric echocardiographic measurements, we compared local measurements with those made at a central facility. METHODS AND RESULTS:The comparison was based on the first echocardiographic recording obtained on 735 children of HIV-infected mothers at 10 clinical sites focusing on...
journal_title:Circulation
pub_type: 临床试验,杂志文章,多中心研究
doi:10.1161/01.cir.104.3.310
更新日期:2001-07-17 00:00:00
abstract:BACKGROUND:The effects of carteolol, a nonselective beta-adrenergic receptor blocker with intrinsic sympathomimetic activity, were compared with those of metoprolol in a murine model of viral myocarditis and dilated cardiomyopathy caused by encephalomyocarditis virus. METHODS AND RESULTS:In the acute experiment, BALB/...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.83.6.2021
更新日期:1991-06-01 00:00:00
abstract:BACKGROUND:Q waves on a 12-lead ECG are markers of a prior myocardial infarction (MI). However, they may regress or even disappear over time, and there is no specific ECG sign of a non-Q-wave MI. Fragmented QRS complexes (fQRSs), which include various RSR' patterns, without a typical bundle-branch block are markers of ...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/CIRCULATIONAHA.105.595892
更新日期:2006-05-30 00:00:00
abstract::The effect of timolol vs placebo on the frequency of anginal episodes, nitroglycerin consumption and exercise performance was investigated in a double-blind, randomized, crossover study in 23 patients with angina pectoris. The optimal dose of timolol (10-30 mg twice daily) for each patient was titrated by exercise stu...
journal_title:Circulation
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1161/01.cir.61.1.66
更新日期:1980-01-01 00:00:00
abstract:BACKGROUND:Connexin (Cx)40 and Cx45 are the major protein subunits of gap junction channels in the conduction system of mammals. To determine the role of Cx40, we correlated cardiac activation with Connexin distribution in normal and Cx40-deficient mice hearts. METHODS AND RESULTS:Epicardial and septal activation was ...
journal_title:Circulation
pub_type: 杂志文章
doi:10.1161/01.cir.103.11.1591
更新日期:2001-03-20 00:00:00