Background-Magnetic resonance spectroscopy can quantify myocardial triglyceride content in type 2 diabetic patients.Its relation to alterations in left (LV) and right (RV) ventricular myocardial functions is unknown. Methods and Results-A total of 42 men with type 2 diabetes mellitus were recruited. Exclusion criteria included hemoglobin A 1c Ͼ8.5%, known cardiovascular disease, diabetes-related complications, or blood pressure Ͼ150/ 85 mm Hg. Myocardial ischemia was excluded by a negative dobutamine stress test. LV and RV volumes and ejection fraction were quantified by magnetic resonance imaging. LV global longitudinal and RV free wall longitudinal strain, systolic strain rate, and diastolic strain rate were quantified by echocardiographic speckle tracking analyses. Myocardial triglyceride content was quantified by magnetic resonance spectroscopy and dichotomized on the basis of the median value of 0.76%. The median age was 59 years (25th and 75th percentiles, 54 and 62 years). Median diabetes diagnosis duration was 4 years, and median glycohemoglobin level was 6.2% (25th and 75th percentiles, 5.9% and 6.8%). There were no differences in LV and RV end-diastolic and end-systolic volume indexes and ejection fraction between patients with high (Ն0.76%) and those with low (Ͻ0.76%) myocardial triglyceride content. However, patients with high myocardial triglyceride content had greater impairment of LV and RV myocardial strain and strain rate. The myocardial triglyceride content was an independent correlate of LV and RV longitudinal strain, systolic strain rate, and diastolic strain rate. Conclusions-High

Background-Diabetic patients have increased interstitial myocardial fibrosis on histological examination. Magnetic resonance imaging (MRI) T 1 mapping is a previously validated imaging technique that can quantify the burden of global and regional interstitial fibrosis. However, the association between MRI T 1 mapping and subtle left ventricular (LV) dysfunction in diabetic patients is unknown. Methods and Results-Fifty diabetic patients with normal LV ejection fraction (EF) and no underlying coronary artery disease or regional macroscopic scar on MRI delayed enhancement were prospectively recruited. Diabetic patients were compared with 19 healthy controls who were frequency matched in age, sex and body mass index. There were no significant differences in mean LV end-diastolic volume index, end-systolic volume index and LVEF between diabetic patients and healthy controls. Diabetic patients had significantly shorter global contrast-enhanced myocardial T 1 time (425Ϯ72 ms vs. 504Ϯ34 ms, PϽ0.001). There was no correlation between global contrast-enhanced myocardial T 1 time and LVEF (rϭ0.14, Pϭ0.32) in the diabetic patients. However, there was good correlation between global contrast-enhanced myocardial T 1 time and global longitudinal strain (rϭϪ0.73, PϽ0.001). Global contrast-enhanced myocardial T 1 time was the strongest independent determinant of global longitudinal strain on multivariate analysis (standardized ␤ϭϪ0.626, PϽ0.001). Similarly, there was good correlation between global contrast-enhanced myocardial T 1 time and septal EЈ (rϭ0.54, PϽ0.001). Global contrast-enhanced myocardial T 1 time was also the strongest independent determinant of septal EЈ (standardized ␤ϭ0.432, PϽ0.001). Conclusions-A shorter global contrast-enhanced myocardial T 1 time was associated with more impaired longitudinal myocardial systolic and diastolic function in diabetic patients. (Circ Cardiovasc Imaging. 2012;5:51-59.)

Both in ischemic and nonischemic VT, critical isthmus sites are typically located in close proximity to the CMR-derived core-BZ transition and to >75% transmural scar. These findings suggest that CMR-derived scar characteristics may guide to critical isthmus sites during VT ablation.

No abstract