independent samples t-test for continuous variables and Fishers Exact Test for cate-gorical variables. Spearman correlation was calculated between select variables andboth post-diagnosis/post-ICD implant survival time. Results: ICDs were placed pre-dominantly for secondary prevention following aborted sudden death or in patientsotherwise deemed to be at high risk for ventricular arrhythmias. Among the totalsample size of 24 patients, 19 patients died during the follow-up period. Meantime from diagnosis to death was 505 days and mean time from ICD implantationto death was 450 days in these patients. Baseline clinical parameters of the group in-cluded left ventricular (LV) ejection fraction of 0.55 6 0.09, posterior wall thicknessof 15 6 3 mm, LV mass of 243 6 101g, LV end-diastolic dimension of 42 6 9mm,PR interval of 191 6 28ms, QRS duration of 102 6 29ms and corrected QT intervalof 451 6 29ms. Comparison of means between survivors and non-survivors acrossvariables did not show significant differences. Conclusions: The prognosis of pa-tients with cardiac amyloidosis remains very poor despite ICD implantation, with lit-tle predictive insight provided by standard clinical measures. The potential survivalbenefit of such therapy appears to be lower when compared to patients with other causesof nonischemic cardiomyopathy. Further evaluation of ICD implantation in cardiacamyloidosis by a randomized prospective study is warranted.

180Mortality Outcomes According to Frequency of Right Ventricular Pacing(RVP): Does More RVP Shorten Survival?Brent Lampert1, Hans Moore2, Steven Singh2, Brian Lewis2, Ross Fletcher2, PamelaKarasik2; 1Georgetown University Hospital, Washington, DC; 2Veterens AffairsMedical Center, Washington, DC

Introduction: Right ventricular pacing (RVP) has been associated with adverse out-comes, such as congestive heart failure and death. Despite the lack of conclusive ran-domized clinical trials, minimizing RVP has become a therapeutic goal. The EasternPacemaker Surveillance Center (EPSC) maintains a large database of transtelephonicmonitoring records (TTMs) and outcomes. It provides the opportunity to retrospec-tively address the question ‘‘Does more RVP shorten survival?’’ Methods: Patientswith permanent pacemakers implanted between January 1, 1995 and December 31,2005 were analyzed. Average frequency of RVP on TTMs was validated using regres-sion analysis as a satisfactory surrogate for overall frequency of RVP measured bydirect pacemaker interrogation. Patients with less than 20% RVP and those withgreater than 80% RVP were compared. Mortality outcomes were analyzed as averagetime to death following pacemaker insertion. Results: From the EPSC registry, 7198patients were identified with six or more TTMs (Mean 5 21 TTMs). When at leastsix TTMs were available there was a strong correlation (R2 5 0.75) between averagefrequency RVP compared to logged overall frequency RVP obtained from pacemakerinterrogations. The average follow-up was 5.3 years. The average age at time of pace-maker implant was significantly higher in the group with O 80% RVP (72 vs. 67years; p ! 0.0001). There were an equal proportion of deaths in each group: 1113deaths (22%) in 4968 patients with O 80% RVP, and 126 deaths (22%) in 565 pa-tients with ! 20% RVP. However the duration of survival, measured as averagetime to death following pacemaker implantation, was 4.7 years with O 80% RVP,and only 4.3 years with ! 20% RVP (p ! 0.0001). Conclusions: Following pace-maker implantation, survival with O 80% RVP was longer than with ! 20% RVP, inthis unselected population. Review of this large clinical database suggests that morefrequent RVP does not shorten survival. Prospective studies would be needed to val-idate these findings.

181Intramural Electrical Dyssynchrony in Pacing-Induced Congestive HeartFailureNilesh Mathuria1, Jianwen Wang2, Robert L. Hood2, April L. Gilbert2, Daryl G.Schulz2, Liyun Rao2, Jeff Siou3, Mihir Naware3, Dorin Panescu3, Hue-Te Shih2,Sherif F. Nagueh2, Dirar S. Khoury2; 1Cardiology, Baylor College of Medicine,Houston, TX; 2Cardiology, Methodist Hospital Research Institute, Houston, TX;3CRMD, St. Jude Medical, Sylmar, CA

Introduction: Inter and intra-ventricular dyssynchrony can develop as a consequenceof congestive heart failure (CHF). The purpose of this study was to investigate intra-mural electrical conduction properties within the left ventricular (LV) wall duringCHF. Hypothesis: Electrical dyssynchrony develops within the LV wall in pacing-induced CHF. Methods: Biventricular pacemakers were implanted in 8 normal mon-grel dogs (mean weight: 38 kg), and continuous rapid right ventricular pacing (rate:230 bpm) was initiated to induce CHF. Echocardiography and catheterization wereperformed biweekly while pacing was temporarily stopped. At each catheterization,an intracardiac electrode-catheter was placed at the LV endocardium precisely oppo-site to the pacemaker coronary sinus lead tip located at the LV epicardium. Intrinsictransmural electrical conduction delay was assessed by recording endocardial elec-trograms via the electrode catheter and epicardial electrograms via the pacemakercoronary sinus lead, both in posterolateral LV. After inducing CHF, pacing wasstopped in 4 dogs to allow for recovery of systolic function. All times were correctedfor heart rate. Results: All dogs developed CHF within 2-4 weeks of pacing frombaseline (EF: 27 6 8 vs. 49 6 4%; LV end-diastolic pressure: 20 6 9 vs. 6 6 3mmHg; QRS: 98 6 8 vs. 70 6 14 msec with no LBBB). Transmural endocardial-to-epicardial intrinsic electrical conduction time lengthened during CHF comparedto baseline (35 6 13 vs. 10 6 5 ms, p ! 0.001). In four dogs recovering from

CHF 6 weeks after termination of pacing, transmural endocardial-to-epicardialconduction time shortened compared to CHF (10 6 9 vs. 39 6 1 ms, p 5 0.006).Conclusions: Electrical intramural dyssynchrony develops as a consequence of pac-ing-induced CHF. Additionally, there is evidence of reversal of electrical intramuraldyssynchrony upon recovery of cardiac function. This novel finding suggests anotheraspect of overall ventricular dyssynchrony that may not be reflected on surface ECGor by routine noninvasive modalities. The benefit of cardiac resynchronization ther-apy for intramural dyssynchrony is unclear and yet to be defined.

The 11th Annual Scientific Meeting � HFSA S127

182Comparison of CRT-D Device Diagnostics in HF Patients with and withoutDiabetes MellitusAndrew Kaplan1, Haresh Sachanandani2, Jon Peterson2, Chris Mullin2, Kellie Berg2;1Cardiovascular Associates of Mesa, Mesa, AZ; 2Boston Scientific CRM, St. Paul,MN

Introduction: Diabetes Mellitus (DM) is an independent predictor of heart failure(HF) and a prevalent co-morbidity. DM patients with HF (DM-HF) have worse out-comes than non-diabetics with HF (ND-HF). BSC CRM RENEWAL� cardiac re-synchronization (CRT) devices measure patient activity, minimum heart rate, andheart rate variability (HRV), an indicator of autonomic tone. While HF and DMare known to reduce HRV, measures of autonomic tone have rarely been studied inthe DM-HF population. Methods: 1232 patients were enrolled in the Cardiac Re-synchronization Therapy Registry Evaluating Patient Response with RENEWALFamily Devices (CRT RENEWAL) study. 959 patients having sufficient device base-line clinical data were analyzed. Two-sided Student’s t-test and Chi-Squared testwere used to analyze differences between groups and interactions of variables andrepeated measures regression models were used to compare diagnostics betweengroups over time. Results: DM was reported in 33.7% of the study patients. An in-creased prevalence of ischemic cardiomyopathy and hypertension besides signifi-cantly increased BMI and systolic BP was observed in the DM-HF group, whileLVEF, NYHA class and diastolic BP were not different. The DM-HF group hada higher number of HF decompensation events (16.1% vs. 8.2%, p ! 0.001). Min-imum HR (D 5 2.9, p ! 0.001) was higher, while SDANN (D 5 10.3, p !0.001), Foot% (D 5 4.1, p ! 0.001) and Activity Log (D 5 0.8, p ! 0.001)were lower in the DM-HF group compared to the ND-HF group after adjusting forbaseline factors. These diagnostics were not significantly different between theType I and Type II DM-HF patients, although Type I patients tended towards higherminimum HR and Activity and lower SDANN and Foot%. Conclusions: CRT de-vice-based measures of HRV and Activity differ significantly between DM-HF andND-HF subjects. Further analysis is required to determine how these differencesmay be useful in evaluating relative risk of DM-HF and ND-HF patients, and differ-entiating diabetic therapy.

CRT RENEWAL Baseline Characteristics

Variable Diabetics (N 5 323) Non-Diabetics (N 5 636) P value

Ischemic (%) 213 (65.9%) 331 (52%) ! 0.001BMI 30.6 6 6.6 28.1 6 6.1 ! 0.001Systolic BP 125.2 6 19.1 122.3 6 19.1 0.03Hypertension (%) 247 (76.5%) 367 (57.7%) ! 0.001

183Patients with Ischemic Cardiomyopathy Have Higher Degrees of DyssynchronyThan Patients with Non-Ischemic Cardiomyopathy as Measured by PhaseAnalysis of Gated SPECT Perfusion ImagingMark A. Trimble1,4, Salvador Borges-Neto1,4, Emily F. Honeycutt4, Ji Chen2, ErnestV. Garcia2, Ami E. Iskandrian3, Eric J. Velazquez1,4; 1Duke University MedicalCenter, Durham, NC; 2Emory University Medical Center, Atlanta, GA; 3TheUniversity of Alabama at Birmingham, Birmingham, AL; 4Duke Clinical ResearchInstitute, Durham, NC

Introduction: Cardiac resynchronization therapy (CRT) is used for the treatment ofpatients with severe heart failure. Approximately 30% of patients do not respond toCRT when QRS duration is used to measure dyssynchrony. We compared the degreeof dyssynchrony as measured by phase analysis of gated SPECT perfusion imaging insubjects with ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy(NICM), and we describe the relationship between resting perfusion defects andmyocardial ischemia and the quantification of dyssynchrony. Hypothesis: Subjectswith ICM have higher levels of dyssynchrony than subjects with NICM. Methods:We developed a Fourier analysis method which converts regional myocardial countsfrom the discrete frames per cardiac cycle into a continuous thickening functionwhich allows fine temporal resolution of the phase of the onset of myocardial thick-ening and its corresponding amplitude. Phase SD, the standard deviation of the dis-tribution of the phase angles, and histogram bandwidth are indices used to quantifymechanical dyssynchrony. We compared these indices in 125 subjects with left ven-tricular dysfunction (ICM, n 5 98 and NICM, n 5 27), and we evaluated the relation-ship between the sum rest and sum difference perfusion scores and mechanical