Optimal Pacing Site Selection In Left Ventricle For Cardiac Resynchronization Therapy By Three-dimensional Speckle Tracking Imaging

[Objective] The aims of this study were to assess the left ventricular systolic function anddyssynchrony by three-dimensional speckle tracking imaging(3D-STI), and with further, toexplore a new way in clinic for the assessment of short-term efficacy of cardiacresynchronization therapy(CRT).[Method]27chronic heart failure patients who admitted at heart center of XiJing Hospitalof the Fourth Military Medical University and underwent CRT were enrolled. All thefollowing indices were measured respectively before and3months after CRT by3D-STI: leftventricular systolic function indices in the16segments including the mean area peakstrain,the mean longitudinal peak strain,the mean circumferential peak strain and the meanradial peak strain（MAS、MLS、MCS and MRS）; The strain-derived dyssynchrony indicesin the16segments including the standard deviation for time to peak of area strain, thestandard deviation for time to peak of longitudinal strain, the standard deviation for time topeak of circumferential strain and the standard deviation for time to peak of radial strain（TAS-SD16、TCS-SD16、TLS-SD16and TRS-SD16）; the biggest differences for time topeak of area strain,for time to peak of circumferential strain,for time to peak of longitudinalstrain and for time to peak of radial strain（TAS-dif、TCS-dif、TLS-dif and TRS-dif）; Therotation and twist indices of3D-STI including peak rotation on apical plane, peak rotation onbasal plane and peak twist angle（RotA、RotB and Twist）, time to peak of the rotation onapical,time to peak of the rotation on bastal and time to peak of the twist(PTRotA、PTRotBand PTtw). The differences of all the indices between before CRT and3months after CRTwere calculated. The correlation between the changes of all the indices and the increase of left ventricular ejection fraction(△EF) were analyzed.[Results] Left ventricular end-systolic volume (3D-LVESV) was decreased3months afterCRT(P＜0.01)and left ventricular ejection fraction (3D-LVEF)was increased3months afterCRT(P＜0.05);MAS、MLS、MCS and MRS were increased3months after CRT(P＜0.05);|△MAS|and|△MLS|were correlated with△EF3months after CRT（r=0.521，P=0.005；r=0.389，P=0.045）; TRS-SD16was decreased3months after CRT(P＜0.05);△TRS-SD16was correlated with△EF3months after CRT (r=-0.56, P=0.002); RotA and Twist wereincreased (P＜0.01)and PTtw was decreased3months after CRT(P＜0.05);△RotA and△Twist were correlated with△EF3months after CRT （r=0.513, P=0.006; r=0.610,P=0.001).[Conclusion] MAS,MLS,MCS,MRS, and strain-derived dyssynchrony, and the twist functionwere improved significantly3months after CRT measured by3D-STI.3D-STI offered a newway for the assessment of short-term efficacy of CRT. [Objective] To investigate the impact on CRT efficacy in patients with chronic heart failurewhen the left ventricular lead position were implanted at the most delayed site analyzed anddefined by three-dimensional speckle tracking imaging(3D-STI); so as to explore a new wayfor the selection of the left ventricular pace mker lead position for CRT.[Method]54chronic heart failure patients who admitted at heart center of XiJing Hospital ofthe Fourth Military Medical University and underwent CRT were enrolled. The most delayedsite of left ventricle was defined by the time to peak of area strain with3D-STI. According tothe consistent extent of left ventricular pacemaker lead position and left ventricular mostdelayed site,54patients were divided into two groups-paced at the most delayed site or nextsite and paced at any other site. The differences of systolic function indices,strain-deriveddyssynchrony indices with3D-STI between the two groups were calculated3months afterCRT. The change rates of all the indices were also compared before and3months after CRTin the two groups.[Results]1. All following indices were no significant differences in the two groups before CRT(P＞0.05): the left ventricular end-diastolic volume,left ventricular end-systolic volume and leftventricular ejection fraction（LVEDV、LVESV、LVEF）by Simpson’s double-plane method;the mean area peak strain, the mean longitudinal peak strain, the mean circumferential peakstrain and the mean radial peak strain all in the16segments（MAS、MLS、MCS、MRS）; thestandard deviation for time to peak area strain, the standard deviation for time to peaklongitudinal strain, the standard deviation for time to peak circumferential strain and the standard deviation for time to peak radial strain all in the16segments（TAS-SD16、TCS-SD16、TLS-SD16、TRS-SD16）; the biggest differences for time to peak area strain, fortime to peak circumferential strain, for time to peak longitudinal strain and for time to peakradial strain（TAS-dif、TCS-dif、TLS-dif、TRS-dif）with3D-STI.2. LVEF, MAS, MLS in group that paced at the most delayed site or next site were increasedthan those paced at any other site3months after CRT(P＜0.05). The TAS-SD16、TCS-SD16、TRS-SD16in group that paced at the most delayed site or next site were reducedthan those paced at any other site3months after CRT (P＜0.05). The change rates of LVEF,MAS,MLS, TAS-SD16, TRS-SD16（△EF%、△MAS%、△MLS%、△TAS-SD16%、△TRS-SD16%）were increased than paced at any other site3months after CRT.[Conclusion]Left ventricular systolic function and strain-derived dyssynchrony wereimproved significantly in group that paced at the most delayed site or next site3months afterCRT;3D-STI was a new method for the selection of left ventricular pacemaker lead positionfor CRT.