Cardiac exercise imaging using a 3-tesla magnetic resonance-conditional pedal ergometer: Preliminary results in healthy volunteers and patients with known or suspected coronary artery disease

Background: Cardiac magnetic resonance imaging (CMR) remains underutilized as an exercise imaging modality, mostly because of the limited availability of MR-compatible exercise equipment. This study prospectively evaluates the clinical feasibility of a newly developed MR-conditional pedal ergometer for exercise CMR Methods: Ten healthy volunteers (mean age 44 ± 16 years) and 11 patients (mean age 60 ± 9 years) with known or suspected coronary artery disease (CAD) underwent rest and post-exercise cinematic 3T CMR. Visual analysis of wall motion abnormalities (WMA) was rated by 2 experienced radiologists, and volumes and ejection fractions (EF) were determined. Image quality was assessed by a 4-point Likert scale for visibility of endocardial borders.  Results: Median subjective image quality of real-time Cine at rest was 1 (IQR 1–2) and 2 (IQR 2–2.5) for post-exercise real-time Cine (p = 0.001). Exercise induced a significant increase in heart rate (62 [62–73] to 111 [104–143] bpm, p < 0.0001). Stroke volume and cardiac index increased from resting to post-exercise conditions (85 ± 21 to 101 ± 19 mL and 2.9 ± 0.7 to 6.6 ± 1.9 L/min/m2, respectively; both p < 0.0001), driven by a reduction in end-systolic volume (55 ± 20 to 42 ± 21 mL, p < 0.0001). Patients (2/11) with inducible regional WMA at high-resolution post-exercise cine imaging revealed significant coronary artery stenosis in subsequently performed invasive coronary angiography.  Conclusion: Exercise-CMR using our newly developed 3T MR-conditional pedal ergometer is clinically feasible. Imaging of both cardiac response and myocardial ischemia, triggered by dynamic stress, is rapidly conducted while the patient is near their peak heart rate

Predictors of Long-Term Outcome in STEMI and NSTEMI—Insights from J-MINUET

Although patients with ST-segment elevation myocardial infarction (STEMI) and non-ST- segment elevation myocardial infarction (NSTEMI) share similar risk factors and comparable pathophysiology [...

Culprit Lesion Vessel Size and Risk of Reperfusion Injury in ST‐Segment Elevation Myocardial Infarction: A Cardiac Magnetic Resonance Imaging Study

Background Microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH) are well‐established imaging biomarkers of failed myocardial tissue reperfusion in patients with ST‐segment elevation–myocardial infarction treated with percutaneous coronary intervention. MVO and IMH are associated with an increased risk of adverse outcome independent of infarct size, but whether the size of the culprit lesion vessel plays a role in the occurrence and severity of reperfusion injury is currently unknown. This study aimed to evaluate the association between culprit lesion vessel size and the occurrence and severity of reperfusion injury as determined by cardiac magnetic resonance imaging. Methods and Results Patients (n=516) with first‐time ST‐segment–elevation myocardial infarction underwent evaluation with cardiac magnetic resonance at 4 (3–5) days after infarction. MVO was assessed with late gadolinium enhancement imaging and IMH with T2* mapping. Vessel dimensions were determined using catheter‐based reference. Median culprit lesion vessel size was 3.1 (2.7–3.6) mm. MVO and IMH were found in 299 (58%) and 182 (35%) patients. Culprit lesion vessel size was associated with body surface area, diabetes, total ischemic time, postinterventional thrombolysis in myocardial infarction flow, and infarct size. There was no association between vessel size and MVO or IMH in univariable and multivariable analysis (P>0.05). These findings were consistent across patient subgroups with left anterior descending artery and non–left anterior descending artery infarctions and those with thrombolysis in myocardial infarction 3 flow post–percutaneous coronary intervention. Conclusions Comprehensive characterization of myocardial tissue reperfusion injury by cardiac magnetic resonance revealed no association between culprit lesion vessel size and the occurrence of MVO and IMH in patients treated with primary percutaneous coronary intervention for ST‐segment–elevation myocardial infarction