084 Additive role of beta blockade in determining positive response to cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) and beta blockers (BB) are effective in advanced heart failure (HF). Often, due to side effects, BB are not used or dose not increased. We evaluated the titration of BB therapy with carvedilol (Carv) in CRT Responders (R) and Not Responders (NR), recruiting 65 HF outpatients (pts) with CRT indication and on optimal treatment [70% males; age 67.9±12.6 years, ys; NYHA 2.7±0.7; aetiology 44% coronary artery disease (CAD), 43% dilated cardiomyopathy (DCM)]. All underwent ECG, echocardiography, NYHA evaluation before and after 1 y of CRT. Considering NYHA response and improvement of systolic left ventricular function (EF,%), R (ΔNYHA> 1 and/or ΔEF> 5%) and NR were defined. During follow-up, Carv was titrated. Basally R and NR were similar for age, sex, HF aetiology (R 40% CAD, 42.5% DCM; NR 48% CAD, 40% DCM), QRS duration (168±32 vs 178±29 msec), end-diastolic (EDV, ml), end-systolic (ESV) volume, EF (R 25.1±7.9 NR 27.4±8.2), BB treatment (85 vs 88%) and Carv dose (16.3±18.6 vs 13.2±10.3 mg/day). Only basal NYHA (R 2.9±0.7 NR 2.4±0.6, p=0.002) was significantly different. There was no significant difference in QRS duration postCRT (R 123±32, NR 127±36 msec). After 1 y, R showed greater variation of EDV and ESV (ΔEDV -45±46 vs -2±56 p=0.01; ΔESV -46±46 vs -1±45 p=0.003) and mitral regurgitation entity (-0.5±0.7 vs 0±0.7 p=0.02). After 1 y there was an overall increase of pts on BB (92.5 vs 92%), but R achieved a greater Carv dose (25.1±20.4 vs 14.5±7.3 mg/day p=0.002, Δdose 8.7±11 vs 1.2±10.7 p=0.009). Carv dose increase and EF improvement were correlated (r=0.40, p=0.02), while dose increase and ventricular remodeling (LVR) were negatively related (ΔEDV r=0.42 p=0.02; ΔESV r=0.45 p=0.01). In both groups CRT allows to introduce and augment BB dose, but only in R dose increase is statistically significant, correlating with LVR regression. Such results suggest an addictive role of BB titration in determining CRT positive response.