doi: 10.1161/CIRCULATIONAHA.105.538025
(Circulation. 2005;112:e70.)
© 2005 American Heart Association, Inc.
Correspondence |
Letter Regarding Article by Thambo et al, "Detrimental Ventricular Remodeling in Patients With Congenital Complete Heart Block and Chronic Right Ventricular Apical Pacing"
Clinic for Congenital Heart Defects and Pediatric Cardiology, Deutsches Herzzentrum Berlin, Berlin, Germany
We read with great interest the article by Thambo et al,1 and we congratulate the authors on this important work. We have conducted a similar study in children and adults with congenital atrioventricular block as well as other congenital heart diseases. Our initial results indicate significant left ventricular asynchrony and altered global left ventricular function after long-term right ventricular pacing, which is in agreement with Thambo et al. However, we would like to comment on the technical methods used by Thambo et al to evaluate asynchrony.
Preimplantation asynchrony was assessed retrospectively by pulsed Doppler and M-mode echocardiography. This method may yield no precise data on ventricular asynchrony and regional mechanoelectrical interaction. Postimplantation ventricular asynchrony was assessed by tissue Doppler–derived velocity. In contrast, we use tissue Doppler–derived strain to determine the left ventricular asynchrony.2 Tissue Doppler–derived strain is not influenced by the overall heart motions and tethering effects; thus, we believe that it is more promising than is tissue Doppler–derived velocity in assessing ventricular asynchrony.
From the figures presented in their article we believe that Thambo’s group used a wide sector tissue Doppler technique to evaluate ventricular asynchrony; however, this has 2 disadvantages for tissue Doppler imaging. First, it will reduce the frame rate of the obtained loop, which is unacceptable for measuring short cardiac events. Second, strain and strain rate measurements are angle dependent, possibly more so than are other Doppler modalities. If the regional myocardial strain of the interventricular septum and the ventricular lateral wall is determined simultaneously (the method used by Thambo et al), then the angle between the beam and the walls of interest could be >30°. This will make the interpretation of the strain and strain rate curve inaccurate. Incidentally, the authors’ Figure 2 displays a tissue Doppler–derived strain tracing, not strain rate as mentioned in the legend.
In their study, Thambo et al found that the patients were heterogeneous regarding the time of implantation of the pacemaker and the implanted lead system. It would be interesting to know whether there was any significant difference in asynchrony data between the initially implanted epicardial and the transvenous lead systems.
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 Top References References |
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- Thambo JB, Bordachar P, Garrigue S, Lafitte S, Sanders P, Reuter S, Girardot R, Crepin D, Reant P, Roudaut R, Jais P, Haissaguerre M, Clementy J, Jimenez M. Detrimental ventricular remodeling in patients with congenital complete heart block and chronic right ventricular apical pacing. Circulation. 2004; 110: 3766–3772.
[Abstract/Free Full Text]
- Abd El Rahman MY, Hui W, Ygitbasi M, Desebissowa F, Schubert S, Hetzer R, Lange PE, Abdul-Khaliq H. Detection of left ventricular asynchrony in patients with right bundle branch block after repair of tetralogy of Fallot using tissue Doppler imaging derived strain. J Am Coll Cardiol. 2005; 45: 915–921.
[Abstract/Free Full Text]
Response
Hôpital Cardiologique du Haut Lévêque, Université Victor Segalen Bordeaux II, Bordeaux, France
We thank Dr Abdul-Khaliq and colleagues for their interest in our article.1 They have conducted a study on patients with congenital heart disease and prolonged right ventricular pacing. They observed the same detrimental effect of this pacing site2; however, Dr Abdul-Khaliq suggests in this letter that the technical method used to assess ventricular dyssynchrony in our study may not be optimal.
With regard to the preimplantation analysis, the dyssynchrony was measured with pulsed Doppler and M-mode echocardiography. This first measurement, in spontaneous rhythm, was taken during the childhoods of these patients. Tissue Doppler imaging (TDI) technology was not available at that time. In non–pacemaker-dependent patients who switched their pacemakers off, we could compare the parameters of dyssynchrony with TDI techniques in spontaneous and paced ventricular activation. We could demonstrate a major increase in TDI ventricular dyssynchrony when the patients were paced.
In our study, so as not to speculate on only one parameter, we assessed dyssynchrony by a combination of M-mode, conventional Doppler recordings, TDI parameters, and strain measurements, according to the majority of published studies validating each approach individually.3 From a physical point of view, we easily understand the limitations of each parameter. We agree that a low frame rate in TDI acquisition could generate a decrease in the temporal resolution, limiting the interpretation of depicted curves. Our system, however, was set to increase the frame rate to 100 Hz, which is largely superior to conventional 2D imaging. In parallel, a wide sector is mandatory to analyze simultaneously myocardial segments from 2 opposite walls (ie, septal and lateral walls). This approach limits misunderstanding from pulsed TDI successive acquisitions. With regard to strain limitations described by Dr Abdul-Khaliq, we agree that TDI-derived strain is probably limited by its angle dependency.4 This limitation obviously targets strain or TDI amplitudes, which could vary with Doppler angle but not with events in time (curve variations). Therefore, our data remain consistent, as do our conclusions.
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TopReferencesReferences |
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- Thambo JB, Bordachar P, Garrigue S, Lafitte S, Sanders P, Reuter S, Girardot R, Crepin D, Reant P, Roudaut R, Jais P, Haissaguerre M, Clementy J, Jimenez M. Detrimental ventricular remodeling in patients with congenital complete heart block and chronic right ventricular apical pacing. Circulation. 2004; 110: 3766–3772.
[Abstract/Free Full Text]
- Abd El Rahman MY, Hui W, Ygitbasi M, Desebissowa F, Schubert S, Hetzer R, Lange PE, Abdul-Khaliq H. Detection of left ventricular asynchrony in patients with right bundle branch block after repair of tetralogy of Fallot using tissue Doppler imaging derived strain. J Am Coll Cardiol. 2005; 45: 915–921.
[Abstract/Free Full Text]
- Yu CM, Fung JW, Zhang Q, Chan CK, Chan YS, Lin H, Kum LC, Kong SL, Zhang Y, Sanderson JE. Tissue Doppler imaging is superior to strain rate imaging and postsystolic shortening on the prediction of reverse remodeling in both ischemic and nonischemic heart failure after cardiac resynchronization therapy. Circulation. 2004; 110: 66–73.
[Abstract/Free Full Text]
- Urheim S, Edvardsen T, Torp H, Angelsen B, Smiseth OA. Myocardial strain by Doppler echocardiography. Validation of a new method to quantify regional myocardial function. Circulation. 2000; 102: 1158–1164.
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