Cardiac resynchronization therapy (CRT) is a disease modifying therapy in patients with chronic heart failure (CHF). Eligibility for CRT is based on QRS duration and NYHA functional capacity only. However, one-third of CHF patients does not benefit from CRT. Moreover, CRT is associated with malfunction and high costs. This study evaluated whether 123I-mIBG assessed cardiac sympathetic activity could optimize CRT patient selection.
42 stable CHF subjects (age 65.5±8.5 years, LVEF 23±6.5%) referred for CRT-defibrillator implantation were enrolled. All subjects underwent planar 123I-mIBG scintigraphy prior to CRT implantation. Early and late heart-to-mediastinum (H/M) ratio and 123I-mIBG washout (WO) were calculated. CRT response was defined as improvement of NYHA functional class, LVEF and QRS duration after 1 year follow-up.
Response to CRT differed depending on the parameter used: i.e. improvement of NYHA functional class (n=24), LVEF (n=28) and QRS duration (n=26). Only improvement in NYHA functional class was independently predicted by WO (p=0.003). None of the other 123I-mIBG parameters was associated with CRT response.
In stable CHF cardiac 123I-mIBG WO is associated with improvement of NYHA functional class as a measure of CRT response. Therefore, cardiac 123I-mIBG scintigraphy might help to optimize CRT patient selection.