Objectives The aim of this study was to test the hypothesis that strain echocardiography might improve arrhythmic risk stratification in patients after myocardial infarction (MI). Background ...Prediction of ventricular arrhythmias after MI is challenging. Left ventricular ejection fraction (LVEF) <35% is the main parameter for selecting patients for implantable cardioverter-defibrillator therapy. Methods In this prospective, multicenter study, 569 patients >40 days after acute MI were included, 268 of whom had ST-segment elevation MIs and 301 non–ST-segment elevation MIs. By echocardiography, global strain was assessed as average peak longitudinal systolic strain from 16 left ventricular segments. Time from the electrocardiographic R-wave to peak negative strain was assessed in each segment. Mechanical dispersion was defined as the standard deviation from these 16 time intervals, reflecting contraction heterogeneity. Results Ventricular arrhythmias, defined as sustained ventricular tachycardia or sudden death during a median 30 months (interquartile range: 18 months) of follow-up, occurred in 15 patients (3%). LVEFs were reduced (48 ± 17% vs. 55 ± 11%, p < 0.01), global strain was markedly reduced (−14.8 ± 4.7% vs. −18.2 ± 3.7%, p = 0.001), and mechanical dispersion was increased (63 ± 25 ms vs. 42 ± 17 ms, p < 0.001) in patients with arrhythmias compared with those without. Mechanical dispersion was an independent predictor of arrhythmic events (per 10-ms increase, hazard ratio: 1.7; 95% confidence interval: 1.2 to 2.5; p < 0.01). Mechanical dispersion and global strain were markers of arrhythmias in patients with non–ST-segment elevation MIs (p < 0.05 for both) and in those with LVEFs >35% (p < 0.05 for both), whereas LVEF was not (p = 0.33). A combination of mechanical dispersion and global strain showed the best positive predictive value for arrhythmic events (21%; 95% confidence interval: 6% to 46%). Conclusions Mechanical dispersion by strain echocardiography predicted arrhythmic events independently of LVEF in this prospective, multicenter study of patients after MI. A combination of mechanical dispersion and global strain may improve the selection of patients after MI for implantable cardioverter-defibrillator therapy, particularly in patients with LVEFs >35% who did not fulfill current implantable cardioverter-defibrillator indications.
Objectives The purpose of this study was to assess the association of myocardial salvage by cardiac magnetic resonance (CMR) with left ventricular (LV) remodeling and early ST-segment resolution in ...patients with acute myocardial infarction (MI). Background Experimental studies revealed that MI size is strongly influenced by the extent of the area at risk (AAR), limiting its accuracy as a marker of reperfusion treatment efficacy in acute MI studies. Hence, an index correcting MI size for AAR extent is warranted. T2-weighted CMR and delayed-enhancement CMR, respectively, enable the determination of AAR and MI size, and the myocardial salvage index (MSI) is calculated by correcting MI size for AAR extent. Nevertheless, the clinical value of CMR-derived MSI has not been evaluated yet. Methods In a prospective cohort of 137 consecutive patients with acutely reperfused ST-segment elevation MI, CMR was performed at 1 week and 4 months. T2-weighted CMR was used to quantify AAR, whereas MI size was detected by delayed-enhancement imaging. MSI was defined as AAR extent minus MI size divided by AAR extent. Adverse LV remodeling was defined as an increase in LV end-systolic volume of ≥15%. The degree of ST-segment resolution 1 h after reperfusion was also calculated. Results AAR extent was consistently larger than MI size (32 ± 15% of LV vs. 18 ± 13% of LV, p < 0.0001), yielding an MSI of 0.46 ± 0.24. MI size was closely related to AAR extent (r = 0.81, p < 0.0001). After correction for the main baseline characteristics by multivariate analyses, MSI was a major and independent determinant of adverse LV remodeling (odds ratio: 0.64; 95% confidence interval: 0.49 to 0.84, p = 0.001) and was independently associated with early ST-segment resolution ( B coefficient = 0.61, p < 0.0001). Conclusions In patients with reperfused ST-segment elevation MI, CMR-derived MSI is independently associated with adverse LV remodeling and early ST-segment resolution, opening new perspectives on its use in studies testing novel reperfusion strategies.
The aim of this study was to determine the feasibility, accuracy, and reproducibility of a novel tracking-based echocardiographic ejection fraction (EF) assessment method in comparison with ...traditional methods based on magnetic resonance imaging and echocardiography.
In a prospective assessment, apical echocardiographic grayscale image loops from 81 patients were read in random order by four experienced readers, blinded to any data of the cases. In three separate sessions, EFs were estimated using biplane tracking-based assessment and according to the modified Simpson's rule, as well as by visual interpretation in three apical views. Data were compared with a reference EF derived from echocardiography and magnetic resonance imaging.
On average, no significant difference was found between EF estimates of the different methods. Tracking-based EF assessments were possible in 90% of the patients. Tracking-based EF assessments showed slightly higher deviations from the reference EF than the modified Simpson's rule, while interobserver and intraobserver variability of tracking-based assessment were significantly better. Visual interpretation allowed the fastest EF assessment. Tracking-based EF assessment was approximately twice as fast as the modified Simpson's rule.
Tracking-based EF assessment is feasible, has lower interobserver and intraobserver variability, and is faster than traditional echocardiographic EF quantification. Its minimal demand on user interaction makes it a favorable alternative to traditional echocardiographic approaches, with a particular clinical advantage when reliable follow-up measurements are needed.
Velocity vector imaging (VVI) is a new echocardiographic technique of measuring regional myocardial velocities and deformation. Our aim was to evaluate the feasibility and accuracy of VVI in defining ...regional functional abnormalities in patients with an acute myocardial infarction.
Standard echocardiography and delayed enhancement (DE) magnetic resonance imaging were performed in 32 patients (29 men, mean age 61.2 +/- 8.1 years) within 36 hours of primary angioplasty. Twenty healthy volunteers (16 men, mean age 34.6 +/- 6.3 years) served as control subjects. Using VVI for offline analysis, segmental longitudinal deformation indices were measured. Infarcted, adjacent, and remote left ventricular segments were defined according to DE magnetic resonance imaging and coronary angiography. Infarct transmurality was also graded based on the DE extent within each segment on DE magnetic resonance imaging (0%-25%, 26%-50%, 51%-75%, and >76% of wall thickness).
As compared with remote segments, myocardial infarction segments had significantly lower longitudinal systolic strain (S) (-9.6% vs -14.6%, P < .0001), lower S rate (-0.75 vs -1.08 s(-1), P < .0001), and a higher postsystolic S index (21% vs 8.3%, P < .001). By receiver operating characteristic curve analysis, a myocardial peak systolic longitudinal S lower than -6.5% in at least one ventricular segment showed best predictive value (94%) for detecting an infarcted left ventricle. Peak systolic S and S rate were useful predictors of the presence of regional dysfunction, and for the localization and transmural extent of the infarct.
VVI is a promising new tool for studying myocardial motion and deformation with good feasibility in the clinical setting. The assessment of myocardial longitudinal systolic S and S rate with VVI can be used to identify the presence, location, and the transmural extent of myocardial infarction.
Abstract Objectives This study sought to investigate the influence of scar extent and location on the motion pattern of the left ventricle (LV) and its interaction with LV conduction delays. ...Background Different echocardiographic parameters have been proposed to identify responders to cardiac resynchronization therapy based on the detection of LV mechanical dyssynchrony. However, the impact of infarct scar on the diagnostic performance of these parameters remains unknown. Methods We included 11 healthy volunteers and 122 patients with normal and severely reduced function, wide and narrow QRS, as well as with and without infarct scar. Location and extent of infarct scar was defined by contrast-enhanced cardiac magnetic resonance. Influence of infarct scar on the motion pattern of the LV was examined by measuring direction and amplitude of apical rocking. The influence of scar on different echocardiographic dyssynchrony parameters was investigated. Results Scar in the absence of conduction delay caused most apical rocking in the presence of 3 to 4 infarct segments. Pure apical infarction caused no rocking. In wide QRS patients without infarct scar, apical rocking was mainly dominated by the conduction delay, whereas in wide QRS patients with ischemic cardiomyopathy, this pattern was modulated by the scar. Apical rocking was inversely related to scar extent (r = −0.54, p < 0.05). Apical rocking was better associated with cardiac resynchronization therapy response than conventional dyssynchrony measurements. Conclusions LV motion patterns are mainly dominated by conduction delays, but they are also modulated by infarct scar. Higher scar burden resulted in less pronounced apical rocking. Apical rocking is more strongly associated with cardiac resynchronization therapy response than with conventional echocardiographic parameters and may therefore be used as a screening parameter.
Percutaneous coronary intervention (PCI) of the unprotected left main coronary artery (LMCA) is controversial. In 143 patients who underwent PCI of the unprotected LMCA, 30-day mortality was compared ...with predicted cumulative risk-adjusted perioperative surgical mortality based on logistic European System for Cardiac Operative Risk Evaluation. One-year clinical follow-up was completed in all patients. The overall major adverse cardiac event rate at 1 year was 34.3%, reflecting the high-risk profile of the patient population. Twelve patients (8%) experienced an acute myocardial infarction and 16 (11%) underwent target lesion revascularization. In 31 patients (22%) who died during the first year, median logistic European System for Cardiac Operative Risk Evaluation was 30%. Calculated RRs showed significantly lower 30-day mortality using PCI compared with predicted surgical mortality (RR 0.54, 95% confidence interval 0.31 to 0.86). Angiographic follow-up in 90 of the 118 patients alive at 6 months showed binary restenosis of 6% in patients treated with drug-eluting stents versus 29% in patients receiving bare-metal stents (p ≤0.01). In conclusion, PCI for unprotected LMCA disease was associated with acceptable short- and medium-term outcomes in patients at low to intermediate risk of bypass surgery. Mortality remains high in very high-risk patients unsuitable for surgery. However, in selected indications, PCI of the LMCA can offer an alternative to surgery, especially when using drug-eluting stents.
Objectives Our purpose was to evaluate long-term mortality and identify factors associated with 1-year mortality in patients who underwent elective percutaneous coronary intervention (PCI). ...Background While long-term outcomes in PCI patients have been reported previously, limited data are currently available regarding the comparative long-term outcomes in PCI patients who receive enoxaparin versus intravenous unfractionated heparin (UFH). Methods We conducted a follow-up analysis of clinical outcomes at 1 year in patients enrolled in the STEEPLE (SafeTy and Efficacy of Enoxaparin in Percutaneous coronary intervention patients, an internationaL randomized Evaluation) trial of 3,528 patients undergoing elective PCI. Patients were randomized to receive either intravenous 0.50-mg/kg or 0.75-mg/kg enoxaparin or intravenous UFH during elective PCI procedures. All-cause mortality at 1 year after index PCI was the main outcome measure. Results Mortality rates were 1.4%, 2.0%, and 1.5% from 1 month to 1 year, and 2.3%, 2.2%, and 1.9% from randomization to 1 year, after index PCI in patients receiving 0.50 mg/kg enoxaparin, 0.75 mg/kg enoxaparin, and UFH, respectively. Multivariate analysis identified nonfatal myocardial infarction and/or urgent target vessel revascularization up to 30 days after index PCI (hazard ratio: 3.5, 95% confidence interval: 1.7 to 7.3; p < 0.001), and major bleeding within 48 h (hazard ratio: 3.0, 95% confidence interval: 1.1 to 8.5; p = 0.04) as the strongest independent risk factors for 1-year mortality. Conclusions The 1-year mortality rates were low and comparable between patients receiving enoxaparin and UFH during elective PCI. Periprocedural ischemic or bleeding events were the strongest independent predictors of 1-year mortality. (The STEEPLE Trial; NCT00077844 )
Objectives We sought to quantify the myocardium at risk in reperfused acute myocardial infarction (AMI) in man with T2-weighted (T2W) cardiac magnetic resonance (CMR). Background The myocardial area ...at risk (AAR) is defined as the myocardial tissue within the perfusion bed distally to the culprit lesion of the infarct-related coronary artery. T2W CMR is appealing to retrospectively determine the myocardial AAR after reperfused AMI. Data on the utility of this technique in humans are limited. Methods One hundred eight patients with successfully reperfused ST-segment elevation AMI were studied between 1 and 20 days after percutaneous coronary intervention (PCI). We compared the volume of hyperintense myocardium on T2W CMR with the myocardial AAR determined by contrast-enhanced CMR with infarct endocardial surface length (ESL) and AAR estimated by conventional coronary angiography with the BARI (Bypass Angioplasty Revascularization Investigation) risk score. Results The volume of hyperintense myocardium on T2W CMR (mean 32 ± 16%, range 3% to 67%) was consistently larger than the volume of myocardial infarction measured with contrast-enhanced images (mean 17 ± 12%, range 0% to 55%) (p < 0.001). Myocardial salvage ranged from −4% to 45% of the left ventricular myocardium (mean 14 ± 10%). The AAR determined by T2W CMR compared favorably with the infarct ESL (r = 0.77) with contrast-enhanced CMR, and there was moderate correlation between the BARI angiographic risk score and infarct ESL (r = 0.42). The time between PCI and CMR did not cause a significant difference in the volume of T2W hyperintense myocardium (r = 0.11, p = 0.27) or the calculated volume of salvaged myocardium (r = 0.12, p = 0.23). Conclusions T2W CMR performed early after successfully reperfused AMI in humans enables retrospective quantification of the myocardial AAR and salvaged myocardium.
Objectives The objective of this study is to investigate the incidence and clinical implications of thrombus on baseline angiography among patients presenting with non–ST-segment elevation acute ...coronary syndromes (ACS) undergoing percutaneous coronary intervention (PCI). Background Given current advances in the pharmacological and mechanical treatment of ACS patients managed with an early invasive strategy, the incidence and prognostic importance of pre-procedural lesion thrombus is warranted. Methods In the ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) trial, a total of 3,627 patients with moderate- and high-risk ACS undergoing PCI had their baseline and final post-PCI angiograms analyzed by an independent angiographic core laboratory. Results Patients with thrombus (n = 530 15%) compared with those without thrombus had higher rates of impaired final epicardial coronary flow (final Thrombolysis In Myocardial Infarction TIMI flow grade 3: 89.6% vs. 97.1%, p < 0.0001). Thrombus was an independent predictor of 30 day death (odds ratio OR: 3.16 95% confidence interval (CI): 1.20 to 8.37, p = 0.02), and myocardial infarction (MI) at 30 days (OR: 1.62 95% CI: 1.17 to 2.24, p = 0.003) and at 1 year (OR: 1.56 95% CI: 1.16 to 2.08, p = 0.003). Patients with thrombus had significantly higher rates of stent thrombosis (ST) compared with patients without thrombus at 30 days (2.8% vs. 1.1%, p = 0.002) and at 1 year (3.7% vs. 1.8%, p = 0.003), and thrombus was an independent predictor of ST at both 30 days (OR: 2.61 95% CI: 1.38 to 4.91) and 1 year (OR: 2.98 95% CI: 1.64 to 5.42). Conclusions Pre-procedural thrombus was present in 15% of moderate- and high-risk ACS patients undergoing PCI in the ACUITY trial. Baseline thrombus predicts increased ischemic complications at 30 days including a 3-fold increased risk of death as well as MI up to 1 year. Further evaluation of adjunctive pharmacotherapy is needed in this high-risk population.
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