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Background-Tissue Doppler echocardiography-derived strain rate and strain measurements (SDE) are new quantitative indices of intrinsic cardiac deformation. The aim of this study was to validate and compare these new indices of regional cardiac function to measurements of 3-dimensional myocardial strain by tagged MRI. Methods and Results-The study population included 33 healthy volunteers, 17 patients with acute myocardial infarction, and 8 patients with suspected coronary artery disease who were studied during dobutamine stress echocardiography. Peak systolic myocardial velocities were measured by tissue Doppler echocardiography, peak systolic strain rates and strains by SDE, and strains by tagged MRI. In healthy individuals, longitudinal myocardial Doppler velocities decreased progressively from base to apex, whereas myocardial strain rates and strains were uniform in all segments. In patients with acute infarction, abnormal strains clearly identified dysfunctional areas. In infarcted regions, SDE showed 1.5Ϯ4.3% longitudinal stretching compared with Ϫ15.0Ϯ3.9% shortening in remote myocardium (PϽ0.001), and radial measurements showed Ϫ6.9Ϯ4.1% thinning and 14.3Ϯ5.0% thickening (PϽ0.001), respectively. During dobutamine infusion, longitudinal strains by SDE increased significantly from Ϫ13.5% to Ϫ23.8% (PϽ0.01) and radial strains increased from 13.1Ϯ3.1% to 29.3Ϯ11.5% (PϽ0.01). Comparisons between myocardial strains by SDE and tagged MRI in healthy individuals (nϭ11), in infarct patients (nϭ17), and during stress echo (nϭ4) showed excellent correlations (rϭ0.89 and rϭ0.96 for longitudinal and radial strains, respectively, PϽ0.001). Conclusions-The

Background-Contrast-enhanced (CE) MRI demonstrates a pattern of hypoenhancement early after contrast injection in acute myocardial infarction (MI) and a pattern of hyperenhancement late after contrast injection. Because the significance of these CE patterns for myocardial viability remains debated, we evaluated their diagnostic accuracy to quantitatively predict late functional improvement of regional contractility. Methods and Results-Twenty patients underwent CE and tagged MRI at 4 days and again at 7 months after acute MI.Resting circumferential shortening strain (Ecc) was analyzed in 24 segments per patient, and its improvement was correlated with the presence or absence of the CE patterns. Immediately after MI, 389 segments were considered dysfunctional because of having less than meanϮ2 SD Ecc of the remote region (Ϫ18Ϯ4%). At follow-up, significant improvement of Ecc occurred in 170 dysfunctional segments with normal CE (from Ϫ4Ϯ7% to Ϫ12Ϯ7%, PϽ0.001) but not in 60 segments with early hypoenhancement (from Ϫ2Ϯ6% to Ϫ6Ϯ9% Ecc, PϭNS). In 240 dysfunctional segments with delayed hyperenhancement, the improvement of Ecc (from Ϫ2Ϯ6% to Ϫ5Ϯ8%, PϽ0.001) decreased with increasing transmural extent of hyperenhancement. Receiver operating characteristic analysis demonstrated that absence of delayed hyperenhancement, compared with absence of early hypoenhancement, had better sensitivity (82% versus 19%, respectively; PϽ0.001) and accuracy (74% versus 49%, respectively; PϽ0.001) in predicting recovery of Ecc to any given level. Conclusions-Compared with lack of early hypoenhancement, lack of delayed hyperenhancement has better diagnostic accuracy in predicting functional improvement in dysfunctional segments. The early hypoenhanced regions, which represent only the fraction of infarcted tissue with concomitant microvascular obstruction, greatly underestimate the amount of irreversibly injured myocardium present after acute MI.

Background-Tagged MRI of the heart is difficult to implement clinically because of the lack of fast analytical techniques.We investigated the accuracy of harmonic phase (HARP) imaging for rapid quantification of myocardial strains and for detailed analysis of left ventricular (LV) function during dobutamine stimulation. Methods and Results-Tagged MRI was performed in 10 volunteers at rest and during 5 to 20 g Ϫ1 ⅐ kg Ϫ1 ⅐ min

Background-The outcome of resuscitated patients after cardiac arrest complicating acute myocardial infarction remains poor, primarily because of the relatively low success rates of cardiopulmonary resuscitation management. Existing data suggest potential beneficial effects of early myocardial reperfusion, but the predictors of survival in these patients remain unknown. Methods and Results-From 1995 to 2005, 186 patients (78% men; mean age, 60.4Ϯ13.8 years) underwent immediate percutaneous coronary intervention after successful resuscitation for cardiac arrest complicating acute myocardial infarction. Prompt prehospital management was performed by mobile medical care units in 154 of 186 patients, whereas 32 had in-hospital cardiac arrest. Infarct location was anterior in 105 patients (56%), and shock was present on admission in 96 (52%). Percutaneous coronary intervention (stenting rate 90%) was successful in 161 of 186 patients (87%). Six-month survival rate was 100 of 186 (54%), and 6-month survival free of neurological sequelae was 46%. By multivariate analysis, predictors of 6-month survival were a shorter interval between the onset of cardiac arrest and arrival of a first responder (odds ratio, 0.67; 95% CI, 0.54 to 0.84), a shorter interval between the onset of cardiac arrest and return of spontaneous circulation (odds ratio, 0.91; 95% CI, 0.87 to 0.96), and absence of diabetes (odds ratio, 7.30; 95% CI, 1.80 to 29.41). Conclusions-In patients with resuscitated cardiac arrest complicating acute myocardial infarction, prompt prehospital management and early revascularization were associated with a 54% survival rate at 6 months. A strategy including adequate prehospital management, early revascularization, and specific care in dedicated intensive care units should be strongly considered in resuscitated patients after cardiac arrest complicating acute myocardial infarction. (Circulation.