| Background & Objectives The effectiveness of cardiac resynchronization therapy ( CRT ) has been verified by large multi-center studies, but 30-35% of the patients are nonresponders to CRT. Optimization can add the respond to CRT for patients post operation, although there is not a uniform standard. This study was designed to investigate the value of Tei index in the optimization of CRT device.Methods The study subjects consists of 12 patients with chronic heart failure(CHF) who were treated with CRT from March 2006 to June 2008 in the cardiology department of Anhui provincial hospital. 11 men and 1 woman. Average age was 56.5±10.44 years. The underlying cause of cardiac dysfunction was ischemic cardiomyopathy in 3 patients, dilated cardiomyopathy in 9 patients. All the patients were on optimal medical therapy. Ultrasonocardiograph (GE Vivid7) and programming devices (St. Jude Medical.3510) were used to optimize the CRT devices. Atrioventricular delay (AVD) optimization was firstly programmed from 80ms to 180ms in steps of 20ms, comparing echocardiographic immediate parameters difference measured at all AVD and the optimized AVD was set. Optimum AVDs were identified by the minimum Tei index for each patient. The Tei index was calculated as the sum of the isovolumic contraction time (ICT) and isovolumic relaxation time (IRT) divided by the ejection time (ET): Tei index = (ICT + IRT)/ET. Other indexes of echocardiogram included left ventricular ejection fraction (LVEF) and aortic velocity-time integral (VTI). After receiving AVD optimization, the patients receive interventricular delay (VVD) optimization in order to compare the immediate differences of echocardiographic parameters at different VVDs. VVD corresponding to the minima of Tei index was considered to be the best, other indexes of echocardiogram included LVEF, aortic velocity-time integral (VTI) and standard deviation of the time to peak of systolic velocity (Ts-SD).Results The best AVDs respective optimized by the Tei index, VTI and LVEF were 120±21ms, 120±21ms and 122±23ms without significant difference, the individual variability ranging from 80 - 160ms is considerably obvious. Hemodynamics were improved immediately after optimization by Tei index as VTI and LVEF, Tei index descend from 0.72±0.20 to 0.64±0.20, VTI ascended from 14.36±2.89 to 15.70±3.70, LVEF ascended from 27±4.94 to 29.33±5.38, the difference is significant (P<0.01). After VVD optimization, The LV was stimulated first in 8 patients (8/12), the right in 1 patient (1/12), and simultaneous biventricular pacing was found to be optimal in 3 patients (3/12). Tei index descended from 0.68±0.21 to 0.58±0.15 (P<0.01), VTI ascended from 17.31±2.58cm to 18.47±2.80cm (P<0.05), LVEF ascended from 29.08±5.42 % to 31.75±4.67 % (P<0.01) and Ts-SD descended from 52.47±8.3ms to 43.63±6.73ms (P<0.01). LVEF in different AVDs/VVDs of the small change is not conducive to choose the optimum AVDs/VVDs.Conclusion The hemodynamics of patients who received CRT could be improved immediately after optimization by Tei index, Tei index may be a good choice to optimize AVD and VVD. The variability of Doppler parameters with different CRT modalities underlines the necessity of individualized settings. |
PDF Full Text Request