But their safety in patients with prior cardiac disease, pacemakers or ICDs is questioned. Hence there is a need for additional studies in delineating the safety and side effects of these devices. AB35-3 A CASE WITHOUT HEMODYNAMIC BENEFIT OF RIGHT VENTRICULAR ANODAL CAPTURE DURING BIVENTRICULAR PACING Shinya Kowase, MD, Akihiko Nogami, MD, Yasushi Oginosawa, MD, Aiko Sugiyasu, MD, Shoichi Kubota, MD, Masayuki Igawa, MD, Chieko Arai, MD, Atsushi Sakamoto, MD, Naohisa Nakajima, MD, Hajime Aoki, MD, Kazuhiko Yumoto, MD, Toshiyuki Tamaki, MD and Kenichi Kato, MD. Yokohama Rosai Hospital, Kanagawa, Japan, Yokohama Rosai Hospital, Yokohama, Japan and Hiratsuka Kyosai Hospital, Hiratsuka, Japan. Anodal capture of the right ventricle (RV) has been described for patients with cardiac resynchronization therapy (CRT). However, hemodynamic benefit of RV anodal capture is unknown. A 70-year-old man with myocardial infarction and dual chamber pacemaker for atrioventricular block underwent upgrade to CRT system. A unipolar left ventricular (LV) lead was placed to the antero- lateral vein. During ventricular threshold test, ECG showed 3 different QRS configurations. At an output setting between 0.5 and 1.5 V, RV was only captured (QRS width: 190 ms, Figure A). At an output setting between 2.0 and 4.0 V, RV and LV were captured (QRS width: 135 ms, Figure B). And at an output setting of  5.0 V, both ventricles and the anodal electrode of the RV were captured (QRS width: 130 ms, Figure C). LV systolic pressure and max dP/dt were 104 mmHg and 665 mmHg/s during cathodal RV pacing, 115 mmHg and 853 mmHg/s during biventricular pacing without anodal capture of the RV, and 109 mmHg and 821 mmHg/s during biventricular pacing with additional anodal capture of the RV, respectively. While QRS duration was longer by 5 ms, LV systolic pressure and max dP/dt during CRT without RV anodal capture were greater than those with anodal capture. A ventricular output was programmed at 4.0 V to obtain biventricular pacing without RV anodal capture. After 6 months of effective CRT, the patient’s functional class improved from NYHA III to II, cardiothoracic ratio decreased from 48 to 44 %, LV ejection fraction increased from 23 to 45 %, and B-type natriuretic peptide decreased from 614 to 40 pg/ml. Conclusion: RV anodal capture during biventricular pacing does not al- ways have a hemodynamic benefit. To avoid useless high output setting, the hemodynamic and clinical data should be compared with and without RV anodal capture in individual patients. AB35-4 OPTIMIZATION OF VENTRICULAR SITE AND TIMING FOR BIVENTRICULAR PACING T. Alexander Quinn, MS, George Berberian, MD, Santos E. Cabreriza, BA, Cara A. Garofalo, MD and Henry M. Spotnitz, MD. Columbia University, New York, NY. Introduction: Biventricular pacing (BiVP) is an important evolving ther- apy for heart failure. BiVP optimization (BiVOPT) involves multiple variables, including LV pacing site (LVPS) and RV-LV delay (RLD). No randomized study of site-timing interactions has been reported. Hypothesis: Randomized LVPS-RLD BiVOPT is feasible during cardiac surgery and will enhance cardiac function beyond effects achieved by either alone. Methods: A 71 year-old male diabetic with recurrent bacteremia and advanced dilated cardiomyopathy (QRS 220 msec, ejection fraction 15%, moderate mitral regurgitation, and poor septal-free wall coordination) was referred for pacemaker lead removal on cardiopulmonary bypass (CPB). With informed consent, while cannulating for CPB, bipolar pacing wires were clipped to the RA appendage and anterior RV. A 6 bipolar-electrode, epicardial pacing-array was placed in the posterior pericardium to test LVPS. Pacing wires were connected to a custom temporary pacing unit housing an InSync III. An electromagnetic flow probe was placed on the ascending aorta to measure cardiac output (CO). At a paced heart rate of 90 bpm and an atrioventricular delay of 150 msec, BiVP was tested for 54 LVPS-RLD combinations implemented in random order over 15 sec in- tervals. Nine values of RLD ranged from +80 to -80 msec in 20 msec increments (+RLD = RV-first) and LVPS comprised 6 sites. Results: BiVP narrowed the QRS and increased systolic arterial pressure from 104 to 131 mmHg. Changes in pacing settings resulted in nearly instantaneous and marked alterations in arterial pressure and CO. This complex data set was visualized with a response surface relating LVPS and RLD and expressing CO in color. It revealed a “sweet spot” encompassing the obtuse margin (OM) and circumflex (CIRC) sites over an RLD range of 0 to -40 msec with a 66% improvement in CO when compared to the worst settings. Following CPB, an optimal RLD of -20 msec improved CO by 30% at the OM site and 23% at the CIRC site when compared to the worst RLD. BiVP benefits were demonstrated repeatedly over two weeks prior to discharge. Conclusion: Randomized epicardial BiVOPT is feasible and improves cardiac function beyond single variable optimization. AB35-5 ECHOCARDIOGRAPHIC CONTRAST GUIDED TEMPORARY PACEMAKER PLACEMENT Carlos De Diego, MD, Pedro Marcos-Alberca, MD, Rakesh K. Pai, MD, Jose ´ A. Cabrera, MD, PhD and Jero ´nimo Farre ´, MD, MPH. UCLA, Los Angeles, CA, Fundacio ´n Jime ´nez Dı ´az, Madrid, Spain and University of Utah, Salt Lake City, UT. We describe a case of an elderly patient who presented with symptomatic bradycardia requiring urgent transvenous pacing facilitated by the use of balloon-tipped echocardiographic contrast. A balloon tipped temporary pacemaker (6 Fr catheter) was placed via the right internal jugular ap- proach. Echocardiographic contrast was useful in the placement of the temporary catheter electrode. The pacing catheter was advanced 10 cm into the superior vena cava and 0.4 cc of echo contrast was injected into the balloon lumen of the catheter. Multiple echocardiographic images were interrogated and the apical four chamber and subcostal images were uti- lized to assist in lead placement. The catheter was advanced into the right atrium and was immediately visible on imaging. Initially the pacing cath- eter was observed to cross the tricuspid valve and float into the right ventricular outflow tract and subsequently was pulled back and advanced into the right ventricular apex. The balloon was then deflated and the contrast was removed from the balloon lumen; the capture threshold was assessed in the usual fashion. The Figure demonstrates the endocardial placement of the temporary electrode within the right ventricular apex in S73 Session 35