Abstract 3180: Benefit of Cardiac Resynchronization Therapy is Depending on the Optimal Lead Position as Defined by 3D-Echocardiography
Background:We sought to define in a serial study using 3D-Echocardiography (3DE) the impact of echocardiographically defined LV lead position on the efficacy of cardiac resynchronization therapy(CRT).
Methods:38 consecutive patients (52±9 years,21 men) with heart failure(HF) were included in the study.26 patients (pts) had ischemic,12 pts non-ischemic heart disease.Echocardiograms were performed before CRT and at 7 (±2) months follow-up using a 3D digital ultrasound scanner (iE33,Philips,Andover,MA).Analysis of temporal course of contraction in 16 LV segments (ASE definitiion) was performed offline with using a semiautomatic contour tracing software (LV Analysis,TomTec,Unterschleissheim).Based on the resulting volume-time-curves the segment with the latest minimum of systolic volume in each patient was identified preoperatively(=segment A).Additionally the temporal difference between pre- and postoperative minimum of systolic volume was determined(Dts) for each segment.The segment with the longest Dts was defined to show the greatest effect of CRT.The location of LV lead position was assumed within this segment(=segment B).LV lead position was defined as optimal when segments A and B were equal as non-optimal when they were different.
Results:Using this definition 21 pts showed a non-optimal,17 pts an optimal LV lead position.Before CRT ejection fraction(EF),endsystolic and enddiastolic volumes(LVESV,LVEDV) and peak oxygen consumption(VO2max) were equal in both groups(EF 32±4 vs.31±6%,LVESV 242±92ml vs. 246±88ml,LVEDV 315±82ml vs. 323±90ml,VO2max 14.3±1.4 vs.14.6±1.5 ml/min/kg).At 7 months follow-up pts with an assumed non-optimal LV lead position showed an increase of 6±3%(EF) and 1.5±0.4 ml/min/kg(VO2max) and a decrease of 15±5ml(LVESV) and 22±6ml(LVEDV), pts with an assumed optimal LV lead position 10±1% (p<0.001),2.4±0.3 ml/min/kg (p<0.01),27±7ml (p<0.01) and 33±7ml (p<0.01).
Conclusion:A correspondence of the assumed LV lead position(segment B) and the segment with the latest preoperative LV contraction(segment A) results in a significant greater benefit of EF and VO2max and a greater improvement in LV remodelling in CRT pts.