ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundCommon 3D systems have only limited spatial and temporal resolution (frame rate of 25 Hz). Thin structures such as cardiac valves are not imaged exactly; rapid movement patterns cannot be precisely recorded. The objective of the present project was to achieve radiofrequency (RF) data transmission to the 3D workstation to improve image resolution.Methods and ResultsA commercially available echocardiographic system (5‐MHz transesophageal echocardiography probe) with an integrated raw data interface enables transmission of RF data (up to 40 megabytes per second). A 3D data set may contain up to 3 gigabytes, so that all of the high‐resolution ultrasound information of the 2D image is available. Frame rates of up to 168 Hz result in temporal resolution 6 times that of standard 3D systems. The applicability of the system and the image quality were tested in 10 patients. The structure of the aortic valve and the dynamic changes were depicted by volume rendering. The changes in the orifice areas were measured in frame‐by‐frame planimetry. The mean number of frames recorded per cardiac cycle was 122±16. The improved structural resolution enabled a detailed imaging of the morphology of the aortic cusps. The rapid systolic movement patterns were recorded with up to 51 frames. The high number of frames enabled creation of precise area‐time diagrams. Thus, the individual phases of aortic valve movement (rapid opening, slow valve closing, and rapid valve closing) could be analyzed quantitatively.ConclusionA 3D system based on RF data enables high‐resolution imaging of cardiac movement patterns. This offers new perspectives for qualitative and quantitative analyses, especially of cardiac valves. (Circulation.2003;107:2876‐2879.)

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background—Atrial fibrillation (AF), the most common clinical arrhythmia, is a major cause of morbidity and mortality. Although AF is often associated with other cardiovascular conditions, many patients present without an obvious etiology. Inherited forms of AF exist, but the causative gene has been defined only in a single family. We have identified a large family (family FAF‐1) in which AF segregates as a Mendelian trait.Methods and Results—Thirty‐four family members were evaluated by 12‐lead ECG, echocardiogram, 24‐hour Holter monitoring, and laboratory studies. Individuals with electrocardiographically documented AF were defined as affected. Subjects were considered unaffected if they were >60 years of age, had no personal history of AF, and had no offspring with a history of AF. DNA was extracted and genotypic analyses were performed using polymorphic microsatellite markers. Evidence of linkage was obtained on chromosome 6, with a peak 2‐point logarithm of the odds (LOD) score of 3.63 (&thetas;=0) at the markerD6S1021. A maximal multipoint LOD score of 4.9 was obtained betweenD6S286andD6S1021, indicating odds of ≈100 000:1 in favor of this interval as the location of the gene defect responsible for AF in this family. The LOD scores were robust to changes in penetrance and allele frequency. Haplotype analyses further supported this minimal genetic interval.Conclusion—We have mapped a novel locus for AF to chromosome 6q14‐16. The identification of the causative gene in this interval will be an important step in understanding the fundamental mechanisms of AF.(Circulation.2003;107: 2880‐2883.)

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundAntithrombotic therapy with intravenous heparin in conjunction with aspirin reduces negative cardiovascular (CV) outcomes in patients with acute coronary syndromes. The need for a therapeutic range with the activated partial thromboplastin time (APTT) has not been validated in patients with arterial thrombosis who receive heparin. Therefore, it is unclear whether there is an association between recurrent CV events and low APTT values and between bleeding and high APTT values.Methods and ResultsWe examined the relationship between the APTT and recurrent cardiovascular events and bleeding among 5058 patients with an acute coronary syndrome without ST elevation who received intravenous heparin in the OASIS‐2 trial. The increase in relative risk of recurrent CV events was 1.54 (95% CI 1.10 to 2.15;P=0.01) among patients with APTT values <60 seconds compared with patients with APTT values ≥60 seconds. When patients had persistently subtherapeutic APTT values for more than 48 hours, the increase in relative risk of a recurrent CV event was 1.84 (95% CI 1.25 to 2.70). Higher APTT values were associated with bleeding; for every 10‐second increase in the APTT, the probability of major bleeding was increased by 7% (95% CI 3% to 11%;P=0.0004).ConclusionsIn patients with acute coronary syndromes without ST elevation who are treated with intravenous heparin, our findings justify regular APTT monitoring to minimize recurrent ischemic events and bleeding. (Circulation.2003; 107:2884‐2888.)

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundPrevious studies have reported diffuse destabilization of atherosclerotic plaques in acute myocardial infarction (AMI).Methods and ResultsWe used intravascular ultrasound (IVUS) to assess 78 coronary arteries (38 infarct‐related arteries [IRAs] with culprit and nonculprit lesions and 40 non‐IRAs) from 38 consecutive AMI patients. IVUS analysis included qualitative and quantitative measurements of reference and lesion external elastic membrane (EEM), lumen, and plaque plus media (P&M) area. Positive remodeling was defined as lesion/mean reference EEM>1.0. Culprit lesions were identified by a combination of ECG, wall motion abnormalities (ventriculogram or echocardiogram), scintigraphic perfusion defects, and coronary angiogram. Culprit lesions contained more thrombus (23.7% versus 3.4% in nonculprit IRA plaques and 3.1% in non‐IRA plaques;P<0.0011). Culprit lesions were predominantly hypoechoic (63.2% versus 37.9% of nonculprit IRA plaques and 28.1% of non‐IRA plaques;P=0.0022). Culprit lesions were longer (17.5±10.1, 9.8±4.0, and 10.3±5.7 mm, respectively;P<0.0001), had larger EEM area (15.0±6.0, 11.5±5.7, and 12.6±5.6 mm2, respectively;P±0.0353) and P&M area (13.0±6.0, 7.5±3.7, 9.3±4.3 mm2, respectively;P<0.0001), smaller lumens (2.0±0.9,4.1±3.1, and 3.4±2.5mm2, respectively;P=0.0009), and more positive remodeling (79.4%, 59.0%, and 50.8%, respectively;P=0.0155). The frequency of plaque rupture/dissection was greater in culprit, nonculprit IRA, and non‐IRA plaques in AMI patients than in a control group of chronic stable angina patients with multivessel IVUS imaging.ConclusionsCulprit plaques have more markers of instability (thrombus, positive remodeling, and large plaque mass); however, these markers of instability are not typically found elsewhere. This suggests that the vascular event in AMI patients is determined by local pre‐event lesion morphologies. (Circulation. 2003;107:2889‐2893.)

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundThe prognostic importance of various hemodynamic responses to adenosine infusion in patients undergoing adenosine stress myocardial perfusion stress (MPS) has not been defined.Methods and ResultsWe identified 3444 unique patients (53.5% women, mean age 74.0±8.4 years) who underwent adenosine (with no additional exercise) stress myocardial perfusion single photon emission computed tomography (MPS) and were followed up for 2.0±0.8 years. Multivariable Cox proportional hazards analysis was used to assess the prognostic value of hemodynamic variables in predicting cardiac death (CD). Two hundred twenty‐four CDs (6.5%) occurred during follow‐up. By multivariable analysis, higher rest heart rate (HR) and to a lesser extent lower peak HR were markers of CD. When added to the multivariable model in place of peak and rest HR, the peak/rest HR ratio was an independent predictor of CD. Peak/rest HR ratio additionally risk‐stratified patients within each MPS category. A significant interaction was found between gender and peak systolic blood pressure (SBP), in which there was an increased risk associated with a low peak SBP (<90 mmHg at end of adenosine infusion) in men but not in women.ConclusionsPatients undergoing adenosine stress MPS with high rest HR and low peak/rest HR ratio have increased risk of CD, as do male patients with a low peak SBP. Assessment of the hemodynamic response to adenosine adds incremental prognostic value to MPS results and enhances identification of patients at risk for CD. (Circulation.2003; 107:2894‐2899.)

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundThe relationship between the amount of inducible ischemia present on stress myocardial perfusion single photon emission computed tomography (myocardial perfusion stress [MPS]) and the presence of a short‐term survival benefit with early revascularization versus medical therapy is not clearly defined.Methods and ResultsA total of 10 627 consecutive patients who underwent exercise or adenosine MPS and had no prior myocardial infarction or revascularization were followed up (90.6% complete; mean: 1.9 ±0.6 years). Cardiac death occurred in 146 patients (1.4%). Treatment received within 60 days after MPS defined subgroups undergoing revascularization (671 patients, 2.8% mortality) or medical therapy (MT) (9956 patients, 1.3% mortality;P=0.0004). To adjust for nonrandomization of treatment, a propensity score was developed using logistic regression to model the decision to refer to revascularization. This model (χ2=1822, c index=0.94,P<10‐7) identified inducible ischemia and anginal symptoms as the most powerful predictors (83%, 6% of overall χ2) and was incorporated into survival models. On the basis of the Cox proportional hazards model predicting cardiac death (χ2=539,P<0.0001), patients undergoing MT demonstrated a survival advantage over patients undergoing revascularization in the setting of no or mild ischemia, whereas patients undergoing revascularization had an increasing survival benefit over patients undergoing MT when moderate to severe ischemia was present. Furthermore, increasing survival benefit for revascularization over MT was noted in higher risk patients (elderly, adenosine stress, and women, especially those with diabetes).ConclusionsRevascularization compared with MT had greater survival benefit (absolute and relative) in patients with moderate to large amounts of inducible ischemia. These findings have significant consequences for future approaches to post‐single photon emission computed tomography patient management if confirmed by prospective evaluations. (Circulation.2003;107:2900‐2906.)

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

BackgroundClopidogrel is administered to prevent stent thrombosis; however, the uniformity of platelet inhibition after treatment and the influence of pretreatment reactivity on drug response have not been described.Methods and ResultsPlatelet aggregation (5 and 20 μmol/L ADP), the activation of glycoprotein IIb/IIIa (PAC‐1 antibody), and the expression of P‐selectin were measured in patients undergoing elective coronary stenting (n=96) at baseline and at 2 hours, 24 hours, 5 days, and 30 days after stenting. All patients received aspirin (325 mg). Clopidogrel (300 mg) was administered in the catheterization laboratory and followed by 75 mg daily. There was marked interindividual variability in drug response as measured by all markers that showed a normal distribution. Resistance, defined as baseline aggregation (%) minus posttreatment aggregation (%) ≤10% by 5 μmol/L ADP, was present in 31% and 15% of patients at 5 and 30 days, respectively. Patients with the highest pretreatment platelet reactivity remained the most reactive at 24 hours after treatment (P<0.0001).ConclusionsInterindividual variability in the platelet inhibitory response from clopidogrel occurs in patients undergoing elective coronary stenting. Patients with high pretreatment reactivity are least protected. Alternative pharmacological strategies and the association of adverse ischemic events should be investigated in these patients. (Circulation.2003; 107:2908‐2913.)

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID