Eri Watanabe

Infarct tissue heterogeneity by contrast-enhanced magnetic resonance imaging is a novel predictor of mortality in patients with chronic coronary artery disease and left ventricular dysfunction.

Background—Strategies for prevention of sudden cardiac death focus on severe left ventricular (LV) dysfunction, although most sudden cardiac death postmyocardial infarction occurs in patients with mild/moderate LV dysfunction. We tested the hypothesis that infarct heterogeneity by cardiac magnetic resonance is associated with mortality beyond LV ejection fraction (LVEF) in patients with coronary artery disease and LV dysfunction. In addition, we examined the association between infarct heterogeneity and mortality in those with LVEF >35%. Methods and Results—We studied 301 patients with coronary artery disease and LV dysfunction referred for cardiac magnetic resonance. We quantified total infarct mass, infarct core mass, and peri-infarct zone (PIZ) normalized for total infarct mass (%PIZ) using signal-intensity criteria of >2 SDs, >3 SDs, and 2- to -3 SDs above remote myocardium, respectively. Mean LVEF was 41±14%. After 3.9 years median follow-up, 66 (22%) patients died (13 sudden cardiac death; 33 with LVEF >35%). In patients with LVEF >35%, below-median %PIZ carried an annual death rate of 2.8% versus 12% in patients with above-median %PIZ (P<0.001). In a multivariable model, %PIZ maintained strong association with mortality adjusted to patient age, LVEF, right ventricular ejection fraction, prolonged QT interval, and total infarct size and resulted in improve risk reclassification 0.492 (95% confidence interval, 0.183–0.817). Conclusions—Cardiac magnetic resonance infarct heterogeneity has a strong association with mortality independent of LVEF in patients with coronary artery disease and LV dysfunction, particularly in patients with mild or moderate LV dysfunction. Further studies incorporating cardiac magnetic resonance in clinical decision making for defibrillator therapy are warranted.

Identification of myocardial extracellular matrix expansion by cardiac MRI in hypertensive patients

Background Left ventricular hypertrophy (LVH) is an important marker of adverse prognosis in cardiovascular disease and commonly occurs in association with hypertension. While late gadolinium enhancement (LGE) reflects myocardial replacement fibrosis in hypertensive patients, we hypothesized that the myocardial extracellular volume fraction (MECVF) would better reflect the presence and severity of myocardial fibrosis, including diffuse fibrosis, in hypertensive patients with LVH. We sought to measure the MECVF directly using T1 imaging preand post-contrast.

CARDIAC DIFFUSION WEIGHTED IMAGE IN PATIENTS WITH CARDIAC SARCOIDOSIS: COMPARISON TO 18F-FLUDEOXYGLCOSE PET

Background: This study was to evaluate the feasibility of detecting myocardial active inflammation in patients with cardiac sarcoidosis (CS) using cardiac diffusion weighted image (DWI). Methods: 10 patients (age 61±10, male 6) who underwent both DWI and 18F-Fludeoxyglucose PET (FDG) were enrolled

Myocardial Extracellular Matrix Volume has independent prognostic value in patients with non-ischemic cardiomyopathy

Background Left ventricular ejection fraction (LVEF) is the most validated independent prognostic factor for mortality, ventricular arrhythmias and heart failure (HF) in non-ischemic dilated cardiomyopathy without etiology. However, mild or moderate reduction LVEF yield limited predictive value. The amount of fibrosis, detected by late gadolinium enhancement (LGE) on CMR, has also been validated as an independent predictor factor. Conventional imaging techniques cannot robustly quantify the full spectrum of extracellular cardiac matrix volume (ECV) expansion. ECV expansion often may not be evident on LGE CMR or other modalities. Quantifying ECV may ultimately provide independent prognostic value to improve care through targeted treatment. The aim of this study was to determine the prognostic value of myocardial ECV expansion in patients with nonischemic cardiomyopathy.

Prevalence and characteristics of myocardial crypts in Japanese patients referred for cardiovascular magnetic resonance

Background Myocardial crypts are narrow, blood-filled invaginations within the left ventricle (LV) wall and detected by cardiovascular magnetic resonance (CMR). Recent studies show that a higher prevalence of crypts in patients with hypertrophic cardiomyopathy (HCM) and genotype positive but phenotype negative relatives. Other studies show that myocardial crypts are relatively common in the normal population and incidental variants of local myocardial structures. However, these studies were performed in the western countries and the prevalence and kinds of HCM are different between Japanese and Western people. We aimed to investigate the prevalence and characteristics of myocardial crypts in Japanese people by using CMR. Methods We examined retrospectively 266 consecutive patients (mean age 63.0±15.4 years, 65.8% male) referred for CMR. Crypts were defined as >50% invagination into normal myocardium. We performed 1.5T cardiac MRI including conventional cine imaging and late gadolinium enhancement (LGE) imaging. The location and the number of crypts were evaluated by using a 17-segment model. The prevalence of crypts was compared between patients groups. We also investigated the location of LGE, family history and the first recognition of abnormal ECG in the patients with crypts. Results Crypts were identified in 12 patients (4.5%). Among them, ten patients were with HCM (83%) and 1 patient with congenital heart disease and 1 patient with arrhythmia but with normal structural heart. The prevalence of myocardial crypt is significantly higher in patients with HCM (10 of 82: 12.2%) than in patients without HCM (2 of 184: 1.1%) (P=0.0002). In 10 patients with HCM and crypt, 3 patients had apical hypertrophy. There was no significant difference in prevalence of crypts between HCM patients with apical hypertrophy and those without apical hypertrophy (3 of 23:13.0%, 7 of 59: 11.8%, respectively). Eight patients had single crypt and 4 patients had multiple crypts. All patients had at least one crypt at LV basal level and most popular location was LV basal inferior wall (10 patients). LGE was found in 6 patients and all were with HCM. Two patients had LGE in the same segment with crypt. There were 5 patients with HCM with family histories of sudden death or LV hypertrophy or dilated cardiomyopathy, but no patient without HCM had family history. Abnormal ECG findings were detected under age of 20 in four patients with HCM but in no patients without HCM. Conclusions Myocardial crypts were more frequently seen in the patients with HCM and also seen in the patients with other cardiac diseases in Japan. Although genetic tests were not performed in these patients, genetic factors were suggested in the patients with myocardial crypts and HCM. Funding N/A.

INFARCT TISSUE HETEROGENEITY BY CONTRAST-ENHANCED MRI IS A NOVEL PREDICTOR OF MORTALITY IN PATIENTS WITH CHRONIC CORONARY ARTERY DISEASE AND LEFT VENTRICULAR DYSFUNCTION

Background: Primary prevention of sudden cardiac death (SCD) from coronary artery disease (CAD) focuses on patients with severely reduced left ventricular function although most SCD occurs in patients with only mild or moderate reduction of LV ejection fraction (LVEF). In a consecutive patient cohort with CAD and varying degrees of LV dysfunction, we hypothesized that infarct heterogeneity by cardiac magnetic resonance (CMR) was associated with patient mortality incremental to LVEF. We further examined the strength of this association in CAD patients with LVEF>35%.

Quantitative T1 mapping and the fibrotic index in normal healthy volunteers; relationship to aging and cardiac dimensions

We aimed to publish normal data for the fibrotic index in a group of healthy volunteers. In healthy volunteers, the fibrotic index has acceptable test characteristics, has a range from 0.23 to 0.33, and is associated with age, LA volume and LV mass.

Quantitative of myocardial extracellular volume fraction improves characterization of fibrotic burden in patients with apical hypertrophic cardiomyopathy beyond visual assessment with late gadolinium enhancement

Summary Patients with apical hypertrophic cardiomyopathy (APH) have evidence of increased fibrotic burden, compared to normal controls, in myocardial segments without visible LGE. This finding may have diagnostic implication in patients with thickened apical segments of the LV and a clinical suspicion of APH. Background Apical hypertrophic cardiomyopathy (APH), a variant of hypertrophic cardiomyopathy, is generally considered to have a benign clinical course, with localized hypertrophy and evidence of myofibril disarray and fibrosis at the apex alone. However, traditional late gadolinium enhancement (LGE) techniques are not sensitive enough to detect subclinical apical fibrosis. Accordingly, we hypothesized that quantitative myocardial extracellular collagen volume fraction (MECVF) via T1 mapping techniques at the apex would differentiate patients with and without APH. Methods We performed 3T cardiac MRI in 35 subjects including 11 patients with APH including 3 patients without LGE and 8 with LGE (mean age 48 ± 7 years, all male, diagnosed via standard clinical and echocardiographic assessment), 13 patients with asymmetric septal hypertrophic cardiomyopathy (HCM) including 2 patients without LGE and 11 with LGE (mean age 41 ± 13 years, 62% male) and 11 normal control subjects (mean age 52 ± 12years, 36% male, without cardiac disease or hypertension). MRI included cine imaging, LGE imaging, and a validated Look-Locker gradient echo cine IR technique for quantification of R1 in parallel short-axis locations. The myocardial partition coefficient was estimated by least-squares linear regression of R1 in myocardium against R1 in blood. MECVF was obtained by adjusting the partition coefficient by the patient’s hematocrit. We used a 18-segment model to quantify regional diffuse fibrosis and excluded segments with visible LGE in fibrosis quantification. Results Patients with APH had a trend toward slightly higher MECVF as compared with normal controls at the base (0.30 vs. 0.27; Wilcoxon rank sum P = 0.09) and mid myocardial segments. In apical segments, there was a significant and substantial MECVF (0.38 vs. 0.29; P = 0.0002) in patients with APH compared to normal controls. There were no differences in MECVF between patients with APH and HCM in any segments. Conclusions In patients with APH, MECVF is significantly elevated in the regions of apical segments despite no visualized LGE. These results suggest that myocardial R1

Fibrotic content of LV myocardium quantified by CMR characterizes left atrial sizes and total left atrial emptying function incremental to LV functional parameters and LV myocardial mass index in patients with hypertrophic cardiomyopathy

Fibrotic burden of LV myocardium quantified by CMR provides additional information about LA size and mechanics than morphological severity of LV hypertrophy measured by LV mass index alone.

Feasibility and prognostic value of stress-perfusion CMR in obesity

Background Obesity is an emerging population at high risk for cardiac events for which robust stress imaging techniques are necessary. Stress-perfusion CMR has high image resolution and is less affected by tissue attenuation compared to nuclear scintigraphy. However, its prognostic value in obese patients has not been determined. We hypothesized that stress-perfusion CMR can effectively prognosticate obese patients with suspected myocardial ischemia.