P692A prospective comparison of two optimization techniques in cardiac resynchronization therapy, echocardiography vs device algorithm


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Abstract

Introduction: Cardiac resynchronization therapy (CRT) improves symptoms, quality of life, exercise capacity, hemodynamic and ventricular function and reduces hospitalizations and mortality in selected patients with heart failure. However, up to 30% of patients treated with CRT gain no benefit. One of the proven strategies to improve the response to CRT involves echocardiographyc optimizing the atrioventricular (AV) and interventricular (VV) interval settings, which is costly, time consuming and requires skill and expertise, so is usually undertaken only in non responder patients. An algorithm in St. Jude Medical CRT devices (QuickOpt) claims to optimize these settings automatically. The aim of this study is to compare the two optimization techniques.Method: Optimization of the AV and VV intervals was undertaken in 19 patients (pts) after implantation of CRT, before discharge, first by echocardiography, than by QuickOpt. Left ventricular outflow tract (LVOT) velocity AoVTI was measured after optimization by both techniques. The optimal AV interval was defined as the shortest AV interval that resulted in the maximal EA duration of the transmitral inflow Doppler signal (longest LV filling time) without truncating the A wave of mitral inflow by the onset of ventricular systole. The optimal VV interval was defined as the VV interval that maximized AoVTI (a surrogate measure of stroke volume and cardiac output).Result: There was no statistical difference between optimal AV interval estimated by echocardiography (104±25ms) and QuickOpt method (116±11ms), p=0.094.; as well as between VV interval estimated by echocardiography (21,18±18) vs QuickOpt method (34,12±18), p=0.083. Maximised AoVTI derived from echocardiogaphic measurements was 0.197±0.032 vs 0.197±0.036 derived from QuickOpt, p=ns. There was excellent correlation between optimal AoVTI determined by both methods, r=0.0897, p<0.001.Conclusion: The study demonstrates good agreement in optimal AV and VV intervals determined by echocardiography and than by QuickOpt. Also there was excellent correlation by both method in optimizing AoVTI indicating no diference in haemodynamic response comparing two optimization techniques.

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