A Study Of Optimal VV Delay By An IEGM-Based Method Which Modified With Mechanical Delay Of Left Ventricular Wall Derived From Velocity Vector Imaging

Objective:In this study, Intracardiac Electrocardiogram (IEGM)-based method(M-IEGM) was modified with ventricular dyssynchrony derived from velocity vector imaging(VVI) in cardiac resynchronization therapy(CRT), to evaluate whether M-IEGM-guided Inter-ventricular delay(VVD) optimization is more effective and improve responses comparing with the traditional Intracardiac electrocardiogram (T-IEGM) for cardiac resynchronization therapy in heart failure patients.Methods:This study included 30 patients with congestive heart failure (CHF) patients underwent CRT in our department from May 2014 to June 2015, in line with ESC guidelines CRT I class indications, including Dilated Cordiomyopathy in 27 cases and Ischemic Cardiomyopathy 3cases. Left ventricular long axis dyssynchrony indexes including standard deviation of the time to peak of systolic velocity (Ts-SD) and determination the latest systolic latest segment was derived from velocity vector imaging before CRT. left ventricular free wall and posterior septum physical mechanical delay (A,) and the CHF delay (△,) were derived from velocity vector imaging, then M-IEGM method VVD= 0.5 ×(△,-A,). The M-IEGM method group (study group) 15 cases, Another 15 cases according to the baseline data of 1:1 matching traditional Intracardiac electrocardiogram (IEGM) method as control group. All patients were given optimal medical therapy and implanted CRT. in study group, left ventricular lead was implanted in target vessel which nearest latest segment. study group optimize VVD with M-IEGM method and control group with traditional IEGM. both group optimize AVD by cardiac ultrasound, then enter the follow-up. CRT response was defined as 15% decrease in left ventricular end-systolic volume at 6 months. Comparison between the study group and control group have acute hemodynamic effect and heart function improvement without difference. Using SPSS 19.0 statistical package analysis data,there are significant differences for the P < 0.05.Results:In study group, due to the variation of the coronary vein only 9 cases Left ventricular electrode implantation site are consistent with preoperative latest systolic segment, including 8 responders. and there were 4 responders of other 6 cases. There is no significant differences in response rate between M-IEGM method group(12responsders,80%) and traditional IEGM method(11 responders,73%). M-IEGM method group and traditional IEGM method group of each index comparison results at 6 month are as follows:The optimal VVD (M-IEGM method group 14.7+/-7.4ms and traditional IEGM method group 27.3+/-8.6ms,P<0.05); Left ventricular ejection fraction (M-IEGM method group 38.1+/-4.8% and traditional IEGM method:35.4+/-3.5%, P<0.05). Ts-SD(M-IEGM method group 77.5+/-23.5ms and traditional IEGM method:87.4+/-18.9, P<0.05).Inter-ventricular mechanical delay time (IVMD) (M-IEGM method group 48.2+/-13.8ms and traditional IEGM method:53.2+/-16.0ms, P<0.05). No significant differences was observed between two group in area of mitral valve regurgitation(MRA), Aortic velocity time integral(AVVTI),Left ventricular end-diastolic diameter(LVEDD), Left ventricular end- systolic diameter(LVESD),6 min walk test(6MWT) and Minnesota Living With Heart Failure Questionnaire(MLHFQ).Conclusions:Through determinating left ventricular wall mechanical delay, velocity vector imaging(VVI) can guide the lead placement to the ideal target location. Although M-IEGM method could Improve LV mechanical synchrony and LVEF, has a tendency to increase response rates, whether M-IEGM method improve response rates still need more research because of less samples.