Aims 

Cardiac resynchronization therapy (CRT) is a disease-modifying therapy in patients with chronic heart failure (CHF). Current guidelines ascribe CRT eligibility on three parameters only: left ventricular ejection fraction (LVEF), QRS duration, and New York Heart Association (NYHA) functional class. However, one-third of CHF patients does not benefit from CRT. This study evaluated whether ¹²³I-meta-iodobenzylguanidine (¹²³I-mIBG) assessed cardiac sympathetic activity could optimize CRT patient selection.

Methods and results 

A total of 78 stable CHF subjects (age 66.8 ± 9.6 years, 73% male, LVEF 25.2 ± 6.7%, QRS duration 153 ± 23 ms, NYHA 2.2 ± 0.7) referred for CRT implantation were enrolled. Subjects underwent ¹²³I-mIBG scintigraphy prior to implantation. Early and late heart-to-mediastinum (H/M) ratio and ¹²³I-mIBG washout were calculated. CRT response was defined as either an increase of LVEF to >35%, any improvement in LVEF of >10%, QRS shortening to <150 ms, or improvement in NYHA class of >1 class. In 33 patients LVEF increased to >35%, QRS decreased <150 ms in 36 patients, and NYHA class decreased in 33 patients. Late H/M ratio and hypertension were independent predictors of LVEF improvement to >35% (P=0.0014 and P =0.0149, respectively). In addition, early H/M ratio, LVEF, and absence of diabetes mellitus (DM) were independent predictors for LVEF improvement by >10%. No independent predictors were found for QRS shortening to <150 ms or improvement in NYHA class.

Conclusion 

Early and late H/M ratio were independent predictors of CRT response when improvement of LVEF was used as measure of response. Therefore, cardiac ¹²³I-mIBG scintigraphy may be used as a tool to optimize selection of subjects that might benefit from CRT.

中文翻译：

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CRT植入1年后心脏123I-mIBG闪烁显像与功能反应的关系

目的 

心脏再同步治疗（CRT）是慢性心力衰竭（CHF）患者的一种疾病缓解疗法。当前指南仅将CRT资格归因于三个参数：左心室射血分数（LVEF），QRS持续时间和纽约心脏协会（NYHA）功能类别。但是，三分之一的CHF患者无法从CRT中受益。本研究评估是否¹²³ I-元碘苄（¹²³ I-MIBG）来评估心脏交感活性可以优化CRT患者选择。

方法与结果 

总共纳入了接受CRT植入的78位稳定的CHF受试者（年龄66.8±9.6岁，男性73％，LVEF 25.2±6.7％，QRS持续时间153±23 ms，NYHA 2.2±0.7）。植入前，受试者接受了¹²³ I-mIBG闪烁显像。早期和晚期心脏与纵隔（H / M）之比和¹²³计算I-mIBG洗脱。CRT反应定义为LVEF增加至> 35％，LVEF改善> 10％，QRS缩短至<150 ms或NYHA改善> 1级。在33例患者中，LVEF增至35％以上，QRS在36例患者中<150 ms，NYHA分级在33例患者中降低。晚期H / M比值和高血压是LVEF改善> 35％的独立预测因子（分别为P = 0.0014和P = 0.0149）。此外，早期H / M比，LVEF和无糖尿病（DM）是LVEF改善> 10％的独立预测因素。没有发现QRS缩短至<150 ms或NYHA分级改善的独立预测因素。

结论 

当将LVEF的改善用作反应的量度时，早期和晚期H / M比是CRT反应的独立预测因子。因此，心脏¹²³ I-mIBG闪烁显像术可用作优化可能受益于CRT的受试者选择的工具。