Person:

Nakamori, Shiro

Background: Most patients with implantable cardioverter-defibrillator (ICD) implantation fail to utilize the device resulting in increasing societal costs and patient exposure to device morbidity. We sought to determine whether volumetric cardiovascular magnetic resonance (CMR) left ventricular (LV) spherical remodeling predicts future ventricular arrhythmias in primary ICD patients with reduced LV ejection fraction (EF). Methods: Sixty-eight consecutive patients with transthoracic echocardiographic LVEF <35% referred for CMR prior to ICD implantation for primary prevention of sudden death were identified. Sphericity index was measured as the ratio of LV end-diastolic volume (from cine short axis stack) to the volume of a sphere with a LV end-diastolic 4-chamber length diameter. Results: During a median follow-up of 55 months (interquartile range; 28–88), 15 patients (22%) received appropriate ICD therapy. Multivariable Cox’s proportional hazard modeling identified increased CMR-derived sphericity index as the strongest independent predictor of appropriate ICD therapy (hazard ratio [HR], 1.09; 95% confidence interval [CI], 1.02 to 1.16; p = 0.007). In addition, dichotomized volumetric CMR-derived sphericity index ≥0.57 carried a 4-fold hazard risk for appropriate ICD therapy, controlling for age and LVEF (HR, 4.49; 95% CI, 1.53 to 13.21; p = 0.006). When sphericity index, LVEF and mass index were used in combination, important incremental prognostic information was achieved (net reclassification improvement, 0.42; 95% CI, 0.06 to 0.77). Conclusions: The combined assessment of LV geometry, mass index and systolic function may provide incremental prognostic information regarding ventricular arrhythmia requiring appropriate ICD therapy in primary prevention patients with reduced LVEF.

Background: Recent studies demonstrated a strong association between atrial fibrillation (AF) and epicardial fat around the left atrium (LA). We sought to assess whether epicardial fat volume around the LA is associated with AF, and to determine the additive value of LA‐epicardial fat measurements to LA structural remodeling for identifying patients with AF using 3‐dimensional multi‐echo Dixon fat–water separated cardiovascular magnetic resonance. Methods and Results: A total of 105 subjects were studied: 53 patients with a history of AF and 52 age‐matched patients with other cardiovascular diseases but no history of AF. The 3‐dimensional multi‐echo Dixon fat‐water separated sequence was performed for LA‐epicardial fat measurements. AF patients had significantly greater LA‐epicardial fat (28.9±12.3 and 14.2±7.3 mL for AF and non‐AF, respectively; P<0.001) and LA volume (110.8±38.2 and 89.7±30.3 mL for AF and non‐AF, respectively; P=0.002). LA‐epicardial fat adjusted for LA volume was still higher in patients with AF compared with those without AF (P<0.001). LA‐epicardial fat and hypertension were independently associated with the risk of AF (odds ratio, 1.17; 95% confidence interval, 1.10%–1.25%, P<0.001, and odds ratio, 3.29; 95% confidence interval, 1.17%–9.27%, P=0.03, respectively). In multivariable logistic regression analysis adjusted for body surface area, LA‐epicardial fat remained significant and an increase per mL was associated with a 42% increase in the odds of AF presence (odds ratio, 1.42; 95% confidence interval, 1.23%–1.62%, P<0.001). Combined assessment of LA‐epicardial fat and LA volume provided greater discriminatory performance for detecting AF than LA volume alone (c‐statistic=0.88 and 0.74, respectively, DeLong test; P<0.001). Conclusions: Cardiovascular magnetic resonance 3‐dimensional Dixon‐based LA‐epicardial fat volume is significantly increased in AF patients. LA‐epicardial fat measured by 3‐dimensional Dixon provides greater performance for detecting AF beyond LA structural remodeling.