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Patients with chest pain and a prehospital ST-segment elevation myocardial infarction (STEMI) are preferably treated with immediate percutaneous coronary intervention (PCI). However, patients with normalization of symptoms and ST-segment elevation upon hospital arrival (transient STEMI) received inconsistent therapy due to logistic reasons and the absence of evidence or explicit guidelines. In this trial, the optimal timing of coronary angiography and subsequent revascularisation is investigated in patients presenting with transient STEMI. In this prospective, multicentre, randomized controlled clinical trial, 142 consecutive patients with initially acute chest pain and STEMI, whose symptoms and ST-segment elevation resolve upon admission, are randomized to immediate intervention or a delayed intervention. Primary outcome is infarct size measured at 4 days determined by cardiovascular magnetic resonance. Secondary outcomes are left ventricular function and volumes, myocardial salvage and microvascular injury at baseline; the change in left ventricular function, volumes and infarct size at 4 months; and major adverse cardiac events at 4 and 12 months. The TRANSIENT Trial evaluates whether a delayed invasive strategy (according to NSTEMI-guidelines) is superior to an immediate invasive strategy (according to STEMI-guidelines) in patients with a transient STEMI.

Reperfusion may cause intramyocardial hemorrhage (IMH) by extravasation of erythrocytes through severely damaged endothelial walls. The purpose of the study was to evaluate the clinical significance of IMH in relation to infarct size, microvascular obstruction (MVO) and function in patients after primary percutaneous intervention. Forty-five patients underwent cardiovascular MR imaging (CMR) 1 week and 4 months after primary stenting for a first acute myocardial infarction. T2-weighted spin-echo imaging (T2W) was used to assess infarct related edema and IMH, and delayed enhancement (DE) was used to assess infarct size and MVO. Cine CMR was used to assess left ventricular volumes and function at baseline and at 4 months follow-up. In 22 (49%) patients, IMH was detected as areas of attenuated signal in the core of the high signal intensity region on T2W images. Patients with IMH had larger infarcts, higher left ventricular volumes and lower ejection fraction. Contrast-to-noise ratio (CNR) between hyperintense periphery and the hypo-intense core of the T2W ischemic area correlated to peak CKMB, total infarct size and MVO size. Using univariable analysis, CNR predicted ejection fraction at baseline (beta = -0.62, P = 0.003) and follow-up (beta = -0.84, P < 0.001). However, after multivariable analysis, baseline ejection fraction and presence of MVO were the only parameters that predicted functional changes at follow-up. IMH was found in the majority of patients with MVO after reperfused myocardial infarction. It was closely related to markers of infarct size, MVO and function, but did not have prognostic significance beyond MVO.

Objectives: The aim of this study was to evaluate the effects of alcohol septal ablation (ASA) on coronary blood flow in symptomatic hypertrophic obstructive cardiomyopathy (HOCM) using cardiac MR (CMR) coronary flow measurements. Background CMR flow mapping enables quantification of coronary blood flow in a noninvasive way. Both left ventricular outflow tract (LVOT) gradient reduction and myocardial scarring after ASA are expected to influence left anterior descending (LAD) coronary blood flow., Methods: Cine, contrast-enhanced (CE) imaging and breath-hold CMR phase contrast velocity mapping were performed at baseline and 1 and 6 months after ASA in seven patients. Changes of coronary blood flow were related to left ventricular (LV) mass reduction, enzyme release, volume of ethanol administered, LVOT gradient reduction, and LV rate pressure product (LVRPP)., Results: A significant mass reduction was observed both in the target septal myocardium and in the total myocardium (both P < 0.01). Mean myocardial infarct size was 23 +/- 12 g (range 7.3-41.6 g). LVRPP decreased from 13,268 +/- 2,212 to 10,685 +/- 3,918 at 1 month (P = 0.05) and 9,483 +/- 2,496 mmHg beats/min at 6 months' follow-up (P < 0.01). LAD coronary blood flow decreased from 100 +/- 37 ml/min at baseline to 84 +/- 54 ml/min (P = 0.09) at 1 month and 67 +/- 33 ml/min at 6 months follow-up (P < 0.01). A significant correlation was found between the change in LVRPP and LAD coronary flow at 1 month follow-up (r = 0.83, P = 0.02). CE-infarct size tended to modulate the blood flow changes over time (P = 0.12); no correlation was observed between enzyme release, volume of ethanol or both septal and total mass reduction and coronary blood flow., Conclusion: The reduction in coronary blood flow is primarily associated with diminished LV loading conditions, whereas the induction of metabolically inactive myocardial scar tissue by ASA did not significantly influence the changes in coronary blood flow.

Purpose: To evaluate safety and image quality of cardiovascular magnetic resonance (CMR) at 3.0 T in patients with coronary stents after myocardial infarction (MI), in comparison to the clinical standard at 1.5 T., Methods: Twenty-five patients (21 men; 55 +/- 9 years) with first MI treated with primary stenting, underwent 18 scans at 3.0 T and 18 scans at 1.5 T. Twenty-four scans were performed 4 +/- 2 days and 12 scans 125 +/- 23 days after MI. Cine (steady-state free precession) and late gadolinium-enhanced (LGE, segmented inversion-recovery gradient echo) images were acquired. Patient safety and image artifacts were evaluated, and in 16 patients stent position was assessed during repeat catheterization. Additionally, image quality was scored from 1 (poor quality) to 4 (excellent quality)., Results: There were no clinical events within 30 days of CMR at 3.0 T or 1.5 T, and no stent migration occurred. At 3.0 T, image quality of cine studies was clinically useful in all, but not sufficient for quantitative analysis in 44% of the scans, due to stent (6/18 scans), flow (7/18 scans) and/or dark band artifacts (8/18 scans). Image quality of LGE images at 3.0 T was not sufficient for quantitative analysis in 53%, and not clinically useful in 12%. At 1.5 T, all cine and LGE images were quantitatively analyzable., Conclusion: 3.0 T is safe in the acute and chronic phase after MI treated with primary stenting. Although cine imaging at 3.0 T is suitable for clinical use, quantitative analysis and LGE imaging is less reliable than at 1.5 T. Further optimization of pulse sequences at 3.0 T is essential.

Background: The water-perfusable tissue index (PTI) is assumed to differentiate viable myocardium from scar tissue, but histological comparisons in humans are lacking. The present study compares PTI with delayed contrast-enhanced magnetic resonance imaging (DCE-MRI), a validated marker of fibrotic tissue, in patients with ischemic left ventricular (LV) dysfunction. In addition, the optimal PTI threshold for detection of myocardial viability was defined when DCE-MRI was taken as a reference., Materials: Twenty patients with ischemic LV dysfunction were studied with positron emission tomography, using oxygen-15-labeled water and carbon monoxide as tracers, and DCE-MRI., Results: Of the 200 analyzed segments, 112 demonstrated DCE and were subsequently divided in three subgroups according to the severity of enhancement. PTI was 1.04 +/- 0.21 in control segments and gradually decreased with increasing extent of DCE to 0.77 +/- 0.31 for segments with transmural enhancement (p < 0.001). However, PTI progressively underestimated infarct size with increasing quantities of scar tissue (r = 0.61, p < 0.01). A PTI cutoff value of 0.89 yielded the best diagnostic accuracy for detection of myocardial viability with sensitivity and specificity values of 75 and 77%, respectively., Conclusions: PTI is inversely related to the extent of scar tissue estimated by DCE-MRI in patients with chronic ischemic heart disease and LV dysfunction. However, with increasing quantities of scar tissue, PTI overestimates the extent of residual viable tissue. A PTI threshold of 0.89 yields the best diagnostic accuracy for viability detection.