Aims: To assess if myocardial deformation imaging allows definition of an optimal left ventricular (LV) lead position with improved effectiveness of cardiac resynchronization therapy (CRT) on LV reverse remodelling.
Methods: Circumferential strain imaging based on tracking of acoustic markers within 2D echo images (GE Ultrasound) was performed in 47 heart failure patients (59 +/- 9 years, 28 men) at baseline, one day postoperatively, 3 and 10 months after initiation of CRT. Myocardial deformation imaging was used to determine(1) the segment with latest peak negative systolic circumferential strain prior to CRT, and(2) the segment with maximal temporal difference of peak strain before-to-on CRT as the segment with greatest benefit of CRT and assumed LV lead position. Anatomic LV lead position was determined by fluoroscopy. Optimal LV lead position was defined as concordance or immediate neighbouring of the segment with latest systolic strain prior to CRT and segment with assumed LV lead position.
Results: Agreement of assumed LV lead position based on strain analysis and LV lead position defined by fluoroscopy were high (kappa = 0.847). At 10 month follow-up, there was greater increase of EF (12 +/- 3 vs. 7 +/- 4%, P < 0.001), greater decrease of left ventricular end-diastolic volume (LVEDV) (23 +/- 8 vs. 13 +/- 7 mL, P < 0.001) and left ventricular end-systolic volume (LVESV) (42 +/- 10 vs. 27 +/- 8 mL, P < 0.001), and greater increase of VO(2)max (2.8 +/- 0.8 vs. 1.9 +/- 1.0 mL/kg/min, P = 0.035) in the optimal (n = 28 patients) compared to the non-optimal LV lead position group (n = 19 patients). The distance between segment with latest systolic strain prior to CRT and segment with assumed LV lead position was the only independent predictor of DeltaLVEDV and DeltaLVESV at 10 month follow-up (R(2) = 0.2175, P = 0.0197) and (R(2) = 0.3774, P = 0.0054), respectively.
Conclusion: Detailed analysis of the myocardial contraction sequence using circumferential strain imaging allows determination of the LV lead position in CRT. Optimal LV lead position in CRT defined by circumferential strain analysis results in greater improvement in LV function and more LV reverse remodelling than non-optimal LV lead position.