Circulation. 2006;113:e835-e839
doi: 10.1161/CIRCULATIONAHA.105.589762
(Circulation. 2006;113:e835-e839.)
© 2006 American Heart Association, Inc.
Images in Cardiovascular Medicine |
Two-Dimensional Strain Imaging to Assess the Origin and Extent of Ventricular Preexcitation Associated With an Accessory Bypass
Bart W.L. De Boeck, MD;
Maarten-Jan M. Cramer, MD, PhD;
Peter Loh, MD, PhD;
Pieter A.F.M. Doevendans, MD, PhD
From the Department of Cardiology, University Medical Center Utrecht, the Netherlands.
Correspondence to Bart W.L. De Boeck, MD, Department of Cardiology, E03. 406, University Medical Center Utrecht, Heidelberglaan 100,3583 CX Utrecht, Utrecht, the Netherlands. E-mail bwl.deboeck{at}hli.azu.nl
A 51-year-old, otherwise healthy man with drug refractory Wolff-Parkinson-White syndrome was referred for radio-frequency catheter ablation (RFCA). His ECG exhibited a typical pattern of preexcitation, suggestive of an inferior or inferoseptal bypass (Figure 1A). Before and after RFCA, we acquired B-mode images on a Vivid 7 echocardiography machine (Vingmed Ultrasound, Horten, Norway) from a parasternal short-axis view and 5 apical views (AP2C, AP4C, APLAX, and 2 intermediate planes) at 77 to 91 frames/s, offering an effective temporal resolution of 22 to 26 ms. Off-line, B-mode–based, 2-dimensional (2-D) strain curves were extracted using commercially available software (Echopac version 4.0.2, GE Vingmed Ultrasound, Horten, Norway). The software program performs a frame-by-frame autocorrelation analysis to track the typical speckled myocardial patterns generated by irregularities in acoustic backscatter. In this manner, we were able to obtain angle-independent information on strain (or contraction), which we applied to assess the site of first contraction and the extent of premature ventricular contraction associated with the accessory bypass. Circumferential strain curves localized the site of first ventricular contraction in the inferior wall, just beneath the right ventricular insertion point (Figure 2
A). Analysis of longitudinal strains from the apical views confirmed that the earliest contraction occurred immediately after the onset of the delta-wave at the base of the inferior wall, from where it spread toward the mid-ventricle before merging with the normal activated segments (Figure 2C and 2E). The inferior portion of the right ventricular free wall was activated slightly later (Figure 3). Invasive electrophysiological mapping confirmed a left-sided bypass with an inferoseptal ventricular insertion. Successful RFCA was achieved at the atrial insertion point of the bypass, 1 cm within the coronary sinus at the ostium of the mid-cardiac vein. After RFCA, disappearance of the preexcitation pattern on the ECG (Figure 1B) was accompanied by a homogenization of the timing of contraction throughout the ventricle (Figure 2B, 2D, and 2F).
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Figure 1. A, Standard 12-lead ECG exhibiting a typical pattern of preexcitation, suggestive of an inferoseptal bypass. Also note ventricular ectopy in bigeminus. B, After RFCA, the preexcitation pattern has disappeared.
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Figure 2. Left ventricular strain curves and corresponding M-modes before (A, C, and E) and after (B, D, and F) RFCA. A, Circumferential strain curve at the mitral valve level. Arrow indicates the site of first ventricular contraction in the inferior wall, from where it spreads towards the adjacent segments. B, After RFCA, a homogenization of the timing of contraction is seen. C and E, Longitudinal strain curves from apical views confirm that the earliest contraction occurs immediately after the onset of the delta-wave at the inferior wall, whereas pronounced early systolic prestretching is seen in the anterior wall (C). The premature contraction at the inferior wall spreads toward the mid-ventricle before meeting the normal-timed contraction (E, *). After RFCA, premature contraction at the inferior wall and abnormal prestretch at the anterior wall are abolished, and a normal activation sequence from apex towards the base is seen (D and F).
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Figure 3. Longitudinal strain of the inferior portion of the right ventricular free wall: contraction starts approximately at the end of the delta-wave (*).
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In myocardium with intact excitation-contraction coupling, these electrical and mechanical events are tightly linked. Therefore, previous M-mode and tissue Doppler studies have reported on accessory bypass localization by determining the site of first systolic motion.1 This is the first report on the use of strain imaging to assess the origin of an accessory bypass and to document the extent of ventricular preexcitation. Although the usefulness of tissue Doppler–derived strain imaging has been validated,2 its inherent angle-dependency and 1-dimensional character limits the number of ventricular segments that can be analyzed. In this patient, we used a novel, angle-independent, and 2-D strain imaging technique that recently has been validated.3 In addition to the acoustic pattern–derived strain estimation method used in this case report, another method for calculating 2-D strain data from patterns in myocardial backscatter has been developed and has recently been validated.4,5 Although current B-mode–derived methods may not be fully interchangeable and should be carefully validated, taken together they indicate the potential of multidimensional echocardiographic strain analysis.3–6 The accuracy of such strain analysis is likely enhanced when one can simultaneously assess circumferential, radial, and longitudinal contraction from multiple windows. This case highlights the potential application of 2-D strain imaging in the study of contractile asynchrony.
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Disclosures
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None.
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References
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- Tuchnitz A, Schmitt C, von Bibra H, Schneider MA, Plewan A, Schömig A. Noninvasive localization of accessory pathways in patients with Wolff-Parkinson-White syndrome with the use of myocardial Doppler imaging. J Am Soc Echocardiogr. 1999; 12: 32–40.[CrossRef][Medline]
[Order article via Infotrieve]
- Edvardsen T, Gerber BL, Garot J, Bluemke DA, Lima JA, Smiseth OA. Quantitative assessment of intrinsic regional myocardial deformation by Doppler strain rate echocardiography in humans: validation against three-dimensional tagged magnetic resonance imaging. Circulation. 2002; 106: 50–56.[Abstract/Free Full Text]
- Korinek J, Wang J, Sengupta PP, Miyazaki C, Kjaergaard J, McMahon E, Abraham TP, Belohlavek M. Two-dimensional strain: a Doppler-independent ultrasound method for quantification of regional deformation: validation in vitro and in vivo. J Am Soc Echocardiogr. 2005; 18: 1247–1253.[CrossRef][Medline]
[Order article via Infotrieve]
- Langeland S, D’hooge J, Claessens T, Claus P, Verdonck P, Suetens P, Sutherland GR, Bijnens B. RF-based two-dimensional cardiac strain estimation: a validation study in a tissue mimicking phantom. IEEE Trans Ultrason Ferroelectr Freq Control. 2004; 51: 1537–1546.[CrossRef][Medline]
[Order article via Infotrieve]
- Langeland S, D’hooge J, Wouters PF, Leather HA, Claus P, Bijnens B, Sutherland GR. Experimental validation of a new ultrasound method for the simultaneous assessment of radial and longitudinal myocardial deformation independent of insonation angle. Circulation. 2005; 112: 2157–2162.[Abstract/Free Full Text]
- Ingul CB, Torp H, Aase SA, Berg S, Stoylen A, Slordahl SA. Automated analysis of strain rate and strain: feasibility and clinical implications. J Am Soc Echocardiogr. 2005; 18: 411–418.[CrossRef][Medline]
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Circulation 2006 113: 2565.
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