Roberto Rordorf, MD, Lea Scuteri, MD, Nina AjmoneMarsan, MD, Folco Frattini, MD, Catherine Klersy, MD,DMSc, Giulia Magrini, MD, Stefano Ghio, MD, MaurizioLandolina, MD and Luigi Tavazzi, MD. IRCCS Policlinico S.Matteo, Pavia, Italy and Biometry & Clinical EpidemiologyIRCCS Policlinico S. Matteo, Pavia, Italy.

Purpose: The role of right ventricular (RV) function in modulating theresponsiveness to cardiac resynchronization therapy (CRT) has not beeninvestigated. Aim of this study was to evaluate the role of RV function inpredicting left ventricular (LV) remodeling after CRT.Methods: Twenty-eight pts with dilated cardiomyopathy (9 ischemic, 19idiopathic; NYHA class 2.8 � 0.5, LVEF 22 � 5%,QRS 163 � 29ms)underwent echocardiographic study before, 1 and 6 months after CRT. Stan-dard and tissue Doppler (TDI) echocardiographic evaluation of RV functionwas performed before CRT. Significant LV reverse remodeling was defined asa �15% reduction in end-systolic volume (ESV) at 6 months.Results: We identified 8 pts with severe RV dysfunction defined as Tri-cuspidal Annular Plane Systolic Excursion (TAPSE) �14mm (group A)and 20 pts with TAPSE14mm (group B). The two groups were similar inage, LVEF, LV dimensions, NYHA class and QRS duration. Intra andinterventricular dyssynchrony defined as septal to lateral delay in peakvelocity at TDI and interventricular mechanical delay were similar in thetwo groups both at baseline (62 � 41ms vs. 67 � 29ms; 60 � 22ms vs.63 � 22ms) and at 1 month (34 � 22ms vs. 48 � 38ms; 17 � 12ms vs.24 � 20ms). At 6 months 13% of pts in group A showed significant reverseremodeling compared to 79% in group B (RR 0.24;0.09-0.59, P�0.002).Compared to A group B showed higher LVEF both at 1 month (30 � 6%vs. 22 � 6%, P�0.01) and 6 months (33 � 8% vs. 22 � 5%). At 6 monthsgroup B pts were more likely to be in NYHA I-II as compared to A (85%vs. 38%, P�0.02). At univariate analysis in the overall population TAPSE,RV fractional area shrinkage, systolic pulmonary artery pressure and TDIparameters of regional RV function were found to be predictors of reverseremodeling. When adjusted for confounding variables (ischemic etiology,basal dyssynchrony, NYHA, ESV) TAPSE was the only predictor ofresponse (OR 1.9; 1.04-3.5, P�0.03).Conclusions: Severe RV dysfunction predicts poor LV reverse remodelingafter CRT even if good mechanical resynchronization is obtained. Echo-cardiographic evaluation of RV function may help in identifying non-responders to CRT.

AB33-4

LACK OF ECHOCARDIOGRAPHIC EVIDENCE OFDYSSYNCHRONY PREDICTS POOR RELATIVE SURVIVALFOLLOWING CARDIAC RESYNCHRONIZATION THERAPY (CRT)Bryan Baranowski, MD, Kenneth C. Civello, Jr., MD, BruceL. Wilcoff, MD, Randall Starling, MD and Richard A.Grimm, DO. Cleveland Clinic Foundation, Cleveland, OH.

Background: In select patients with heart failure (HF), CRT has been shown toimprove quality of life, exercise capacity, ejection fraction (EF) and mortality.Recent data suggests that echocardiographic (echo) evidence of dyssynchronypredicts a clinical response to CRT. The goal of this study was to determine if echoevidence of dyssynchrony also predicts survival following CRT.Methods: We identified all patients (n � 84) who had a dyssynchronyevaluation by echo prior to receiving a BiV pacemaker defibrillator(ICD) at the Cleveland Clinic, between 1/1/03 and 3/30/05. Patients hadan EF� 35%, a QRS duration � 120msec and � class II HF. Thepre-CRT dyssynchrony measurements recorded were: septal to poste-rior wall delay (SPWMD), tissue doppler imaging (TDI) of time toonset velocity between opposing walls, and interventricular delay. Pa-tients were separated into two groups based on the presence or absenceof dyssychrony. Dyssynchrony criteria used were: SPWMD �120msec,TDI onset �60msec, and interventricular delay �40msec. If a patienthad 1 or more dyssynchrony criteria they were included in the dyssyn-chrony group. There was no difference in age, EF, MR, QRS, ICDimplantation or HF etiology between the two groups. An ICD wasimplanted in 91% of the no dyssynchrony group and 84% of the

dyssynchrony group. The SSDI was searched through 10/27/05. Sur-vival was measured in days following CRT.Results: There were 7 deaths in the no dyssynchrony group (n�23) and 4deaths in the dyssynchrony group (n�61). This difference was significant,p�0.0052. All deaths in the no dyssynchrony group were in patients with anICD. The Kaplan-Meier curve for survival is plotted below.Conclusion: In class III HF patients with an EF � 35% and QRS �

120msec the absence of echocardiographic evidence of dyssynchrony priorto CRT predicts a poor relative survival.

AB33-5

RIGHT VENTRICULAR OUTFLOW SEPTAL PACING IS CARDIACRESYNCHRONIZATION THERAPY IN PATIENTS WITH RIGHTBUNDLE BRANCH BLOCKMichael C. Giudici, MD, Philip Schrumpf, RN, William J.Fischer III, BA and Roslyn Krupa, RN. Genesis Heart Institute,Davenport, IA and Guidant Corporation, St. Paul, MN.

Background: Studies of cardiac resynchronization therapy (CRT) using leftventricular and right ventricular apex pacing have not shown great benefit inpatients with right bundle branch block (RBBB). Right ventricular outflow(RVOS) pacing has been shown to employ the right bundle branch andHis-Purkinje system. This would suggest that a single RVOS lead pacing theright bundle fused with the patients’ functioning left bundle branch wouldresult in a narrowed QRS and functional improvement in left ventricular (LV)function.Methods: 33 patients (27 M/6 F), age 73 (58-90) yr., with RBBBunderwent placement of RVOS leads for standard pacing or ICD indi-cations. Study leads included Guidant 4054/5, 4087/8, 155/6, 158/9, andMedtronic 6945. The AV delay was then varied over a range of valuesto achieve optimal fusion of the paced and native QRS (narrowestQRS). Echocardiography was performed to evaluate LV function.Results: Baseline mean QRS duration was 14421.0 ms. Fused QRS dura-tion (paced LBBB�nativeRBBB) was 11021.3 ms. p�0.001 (Table) Echo-cardiographic studies demonstrated resolution of the septal contractionabnormalities when paced at the optimal AV delay.Conclusions: RVOS pacing can narrow the QRS complex and restorenormal septal contraction in patients with RBBB. A larger study is ongoingto evaluate this therapy in patients with heart failure.

S69Session 33