Background: Tolvaptan (TLV), a newly-developed vasopressin type 2 receptor antagonist, has a unique feature of diuresis, but the response to this drug can be unpredictable especially in patients with heart failure(HF) with renal dysfunction. This retrospective study used a novel speckle tracking echocardiography to examine the predictability of TLV effectiveness in patients with HF. RV function was estimated by TAPSE and RV strain in this study. Methods: In total, 56 consecutive patients admitted for acute decompensated HF were enrolled (Age72±14 years, 29male). Their ejection fractions were uniformly reduced (HFrEF, LVEF <35%) and CKD stage 3B, 4, 5 (GFR <45ml/min/1.73m2). They were administered TLV at 7.5-15 mg/day for one week. Non-response to TLV was defined as no evidence of a 1 kg decrease in body weight (BW) during the week following TLV treatment. Blood sampling and echocardiography, including strain imaging, were performed just prior to starting TLV. Vivid q and Echo PAC PC (GE, Norway) were used for echocardiographic analyses including strain. We analyzed LV function by lobal longitudinal strain (GLS) and RV systolic function by 2D speckle strain from the 4ch view. Results: Although 46 patients decreased their BW by more than 1kg (Responders; ΔBW= 5.1±0.7kg), 10 patients were non-responders (ΔBW=0.5±0.4kg). Responders achieved the improvements of the symptoms (edema/ congestion). Logistic regression analysis showed that RV dysfunction (RV strain, TAPSE) was the significant predictor for non-responders. On the other hand, eGFR was not significant predictor for non-response to TLV in this population. Conclusions: RV dysfunction may be an important predictor of the effectiveness of TLV in patients with HFrEF with CKD. In particular, RV strain was useful was the useful predictor.