Abstract 3282: Optimizing Cardiac Resynchronization Therapy Using Acoustic Cardiography and AV/VV Delay Maps
Introduction: In cardiac resynchronization therapy (CRT), AV and VV delays are frequently optimized using echocardiography. For efficiency, the optimal AV and VV delays are usually determined serially. Recently, acoustic cardiography (simultaneous digital ECG and heart sound data) has been shown to be an effective method for CRT optimization.
Hypothesis: We hypothesized that CRT optimization can be best achieved using a complete AV/VV map that shows the best combination of AV and VV delays.
Methods: We evaluated 14 patients (86% male, mean age 64 ± 9 years, mean time since implant 15 ± 18 months). Subjects were enrolled >10 weeks post CRT implant. For each patient, we tested a combination of 35 settings (7 AV and 5 VV). Using an AV/VV map (Figure⇓), the optimal combination chosen was that which resulted in the lowest electromechanical activation time (EMAT) - the interval in ms from QRS onset to the mitral component of the first heart sound.
Results: There is a significant difference if AV or VV is done first, due to asymmetry in the AV/VV maps. In comparison to “out-of-the-box” settings, AV/VV delay optimization with acoustic cardiography improved cardiac performance as indicated by significant changes in work capacity, maximum oxygen uptake, oxygen pulse, ejection fraction, end-systolic volume and velocity-time integral in the left ventricular outflow tract. The time required to optimize the pacemaker settings with acoustic cardiography was <30 minutes per patient.
Conclusion: CRT optimization using acoustic cardiography in conjunction with an AV/VV map is an efficient method of improving the results of CRT compared to typical “out-of-the-box” settings.