Predicting the response to cardiac resynchronization therapy using 99mTc-tetrofosmin myocardial scintigraphy in patients with drug-refractory heart failure: additional value of the washout of 99mTc-tetrofosmin

Objective A lack of response to cardiac resynchronization therapy (CRT) has been reported in 20-40% of heart failure patients with left ventricular (LV) dyssynchrony who underwent treatment based on the established guidelines. The study aimed to investigate the relationship between Tc-99m-tetrofosmin (Tc-99m-TF) myocardial scintigraphy and the response to CRT. Patients and methods Twenty-one patients with drug-refractory heart failure who underwent CRT were evaluated. All patients underwent 99mTc-TF myocardial scintigraphy before and after CRT. Single-photon emission computed tomography images of 99mTc-TF were acquired at 30 min and 3 h after injection and were used to determine the total defect score (TDS) and washout score (WOS). The change in the LV volume and ejection fraction (Delta LVEF) and relative reduction in left ventricular end-systolic volume (%Delta LVESV) were calculated as an index of LV functional recovery after CRT. Response to CRT was considered to have occurred when Delta VEF was greater than 15% or when Delta VEF was greater than 5% and %Delta LVESV was greater than 15%. Results Significant differences were observed between the patients who responded to CRT (the responder group, 13 patients) and the nonresponder group (eight patients) for both early and delayed TDS and WOS (P < 0.05). Moreover, there was a good correlation between early TDS before CRT and both Delta VEF and %.LVESV (P < 0.01) and an excellent correlation between WOS before CRT and both Delta VEF and %.LVESV (P< 0.01). Conclusion Evaluating the washout of 99mTc-TF in addition to myocardial perfusion before CRT using 99mTc-TF myocardial scintigraphy might be useful in drug-refractory heart failure patients. (C) 2014 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.