European Heart Journal Advance Access originally published online on February 9, 2008
European Heart Journal 2008 29(5):684-685; doi:10.1093/eurheartj/ehn005
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Impact of left ventricular lead position in cardiac resynchronization therapy on left ventricular remodelling: a circumferential strain analysis based on 2D echocardiography: reply
Department of Cardiology
Medical Clinic I
University Hospital
RWTH University Aachen
Pauwelsstr. 30
52057 Aachen
Germany
Email: mibecker{at}ukaachen.de
Department of Cardiology
Medical Clinic I
University Hospital
RWTH University Aachen
Pauwelsstr. 30
52057 Aachen
Germany
We read with great interest the letter by Ze-Zhou Song,1 which raises some important questions with respect to optimizing cardiac resynchronization therapy (CRT). Ze-Zhou Song stated that current lead implantation strategies are mainly guided by anatomic and not by segmental and functional specifications. This implantation technique may be a reason for unpredictable and potentially disappointing effects to CRT. They raise the issue of structurally and functionally inappropriate pacing sites, in particular infarcted, scarred tissue resulting in impaired electrical and functional activity referring to a recent publication by Arzola-Castaner et al.2 This issue is certainly of considerable importance as akinetic, scarred segments are likely to present non-ideal pacing sites. Magnetic resonance imaging to define scarred tissue and the proximity of cardiac veins for potential left ventricular (LV) lead placement has been proposed for preoperative planing of LV lead position.
As proposed by Ze-Zhou Song, we re-evaluated the 28 patients of our study3 with the LV lead position being ‘optimal’, thus close to the latest contracting segment prior to CRT, to define the additional impact of the LV lead position being in an akinetic segment in comparision with being in a non-akinetic segment. No differences between the two subgroups with regard to subsequent improvement in LV function and LV remodelling could be defined. The number of patients in these subgroups may have been too small to detect significant differences. However, we agree that this important issue may need further analysis in the attempt to prevent non-responders to CRT and optimize the CRT effect.
Ze-Zhou Song discussed also the location of optimal right ventricular (RV) lead placement in CRT. This is another issue which has been discussed more recently.4 In our study, the RV lead was placed in a conventional fashion to obtain the position with known greatest mechanical RV lead stability. Thus, no information can be given on the impact of a variation of RV lead position on CRT results. However, we agree with Ze-Zhou Song that multiple issues with regard to optimal LV and optimal RV lead position as well as the optimal combination of both lead positions are not resolved. Considering the 
30% non-responders to conventional CRT implantation techniques extensive further studies are warranted to define the impact of scar tissue at the site of LV lead placement as well as the impact of an optimal RV lead position on CRT effects.
References
- Ze-Zhou Song. Impact of left ventricular lead position in cardiac resynchronization therapy on left ventricular remodeling. a circumferential strain analysis based on 2D echocardiography. (Letter). Eur Heart J (2008) doi:10.1093/eurheartj/ehn003.
- Arzola-Castaner D, Taub C, Heist EK, Fan D, Haelewyn K, Mela T, Picard M, Ruskin J, Singh J. LV lead proximity to an akinetic segment and impact on outcome of cardiac resynchronisation therapy. J Cardiovasc Electrophysiol (2006) 17:623–627.[CrossRef][Web of Science][Medline]
- Becker M, Kramann R, Franke A, Breithardt OA, Heussen N, Knackstedt C, Stellbrink C, Schauerte P, Kelm M, Hoffmann R. Impact of left ventricular lead position in cardiac resynchronization therapy on left ventricular remodeling. A circumferential strain analysis based on 2D echocardiography. Eur Heart J (2007) 28:1211–1220.
[Abstract/Free Full Text] - Riedelbauchova L, Cihaka R, Bytesnika J, et al. Optimization of right ventricular lead position in cardiac resynchronisation therapy. Eur J Heart Fail (2006) 8:609–614.
[Abstract/Free Full Text]
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