Luca Vitali

Programming Optimal Atrioventricular Delay in Dual Chamber Pacing Using Peak Endocardial Acceleration: Comparison with a Standard Echocardiographic Procedure

DUPUIS, J.‐M., et al .: Programming Optimal Atrioventricular Delay in Dual Chamber Pacing Using Peak Endocardial Acceleration: Comparison with a Standard Echocardiographic Procedure. Optimization of programmed atrioventricular delay in dual chamber pacing is essential to the hemodynamic efficiency of the heart. Automatic AV delay optimization in an implanted pacemaker is highly desirable. Variations of peak endocardial acceleration (PEA) with AV delay at rest correlate well with echocardiography derived observations, particularly with end‐diastolic filling and mitral valve closure timings. This suggests the possibility of devising a procedure for the automatic determination of the optimal AV delay. The aim of this study was to compare a proposed algorithm for optimal AV delay determination with an accepted echocardiographic method. Fifteen patients with high degree AV block received BEST‐Living pacing systems. Automatic AV delay scans were performed at rest (60–300 ms in 20‐ms steps with 60 beats per step) in DDD at 90 ppm, while simultaneously recording cycle‐by‐cycle PEA values, which were averaged for each AV delay to obtain a PEA versus AV delay curve. Nonlinear regression analysis based on a Boltzmann sigmoid curve was performed, and the optimal AV delay (OAVD) was chosen as the sigmoid inflection point of the regression curve. The OAVD was also evaluated for each patient using the Ritter echocardiographic method. Good sigmoid fit was obtained in 13 of 15 patients. The mean OAVD obtained by the PEA sigmoid algorithm was 146.9 ± 32.1  ms , and the corresponding result obtained by echocardiography was 156.4 ± 34.3  ms (range 31.8–39.7 ms). Correlation analysis yielded r = 0.79, P = 0.0012. In conclusion, OAVD estimates obtained by PEA analysis during automatic AV delay scanning are consistent with those obtained by echocardiography. The proposed algorithm can be used for automatic OAVD determination in an implanted pacemaker pulse generator. (PACE 2003; 26:[Pt. II]:210–213)

CRT46: BEAT-TO-BEAT EVALUATION OF SYSTOLIC TIME INTERVALS BY ANALYSIS OF ENDOCARDIAL ACCELERATION

Background Echo evaluation of cardiac timings is a widely recognized method for assessing CRT patients. Endocardial Acceleration (EA), in its systolic (PEA I) and diastolic (PEA II) components, allows estimation of cardiac timings. Aim: to evaluate the correlation between Echo and EA measurements of Aortic Pre-ejection Interval (AoPEI) and Ejection Time (ET). Methods Fifteen CRT patients (10M, age 71.2±7.0 y) (NYHA III-IV, EF 25.6±7.6%) were implanted with Sorin Biomedica Living CHF Pacemakers, able to record and transmit EA signal via telemetry. Several pacing configurations were evaluated for each patient (R, L, Biventricular at different VV and AV delays). EA and Intracardiac EGM were recorded via telemetry for 20 s in each configuration. At the same time, AoPEI and Aortic Valve Closure (AVC) times were measured by Echo. Automatic EA analysis was carried out offline. AoPEI by EA was defined as the interval from the stimulus to the end of PEA I (TPEA1); AVC by EA was defined as the interval between TPEA1 and the onset of PEA II. ET by Echo was defined as the time interval between AoPEI and AVC on the echo tracings. Results AoPEI by Echo was 202.3±24.6 ms; AoPEI by EA was 196.1±29.9 ms (p=ns); correlation between the two was r=0.82 (p>0.0001). ET by Echo was 234.5±34.7 ms; ET by EA was 253.7±37.9 ms (p=ns); correlation between the two was r=0.74 (p>0.0001). Conclusion Echographic and EAbased estimation of systolic timings are well correlated. The chronical monitoring of such parameters by an implanted device using Endocardial Acceleration is attracting and opens new possibilites for day-by-day CRT therapy optimization.