European Journal of Echocardiography Advance Access originally published online on October 22, 2008
European Journal of Echocardiography 2009 10(1):163; doi:10.1093/ejechocard/jen293
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Dynamic left ventricular obstruction evoked by exercise: importance of outflow tract size
Department of Cardiology
Hospital Universitario Virgen de la Victoria
Campus Teatinos sn, Colonia Sta Ines
Malaga 29010
Spain
Tel: +34 659919130
Fax: +34 951032441
E-mail address: fjcabrera{at}secardiologia.es
Department of Cardiology
Hospital Universitario Virgen de la Victoria
Campus Teatinos sn, Colonia Sta Ines
Malaga 29010
Spain
Department of Cardiology
Hospital Universitario Virgen de la Victoria
Campus Teatinos sn, Colonia Sta Ines
Malaga 29010
Spain
Department of Cardiology
Hospital Universitario Virgen de la Victoria
Campus Teatinos sn, Colonia Sta Ines
Malaga 29010
Spain
Department of Cardiology
Hospital Universitario Virgen de la Victoria
Campus Teatinos sn, Colonia Sta Ines
Malaga 29010
Spain
We have read with interest the article by Zywica et al.1 recently published in an issue of the European journal of Echocardiography. The authors analysed, in 300 patients referred for exercise echocardiography, the prevalence and predictive factors of dynamic left ventricular outflow tract obstruction on immediate post-exercise echocardiographic examination.
This phenomenon, which appears in 5% of patients in the Zywica et al.1 series, has been previously described in others works, with frequencies ranging from 1.8 to 13.4%, reaching even 30.4%.2–4 These differences may be attributable to patients selection.
As previously published by our group3 using the same cut-off value of 25 mmHg to define as significative a dynamic gradient, the work of Zywica et al.1 shows how some echocardiographic parameters such as wall thickness and left ventricle diameter are related with the development of dynamic left ventricle outflow tract obstruction (DLVOTO). Nevertheless, in our series of 211 patients with angina or dyspnea referred for treadmill stress echocardiography,3 the main factor related and the only independent predictor for the development of DLVOTO was the indexed left ventricle outflow tract diameter (OR 0.092, 95% CI 0.029–0.275, P < 0.0001). This parameter, which has been related with the development of this phenomenon during dobutamine stress echocardiography too,5 is not included in the analysis of Zywica et al., 1 which could offer confounding results.
Furthermore, on their conclusions, Zywica et al. suggest that exercise echocardiography should be performed in patients with unexplained dyspnea or ischaemia in the absence of coronary artery disease to exclude exercise-induced DLVOTO. In a previous work including 23 patients with effort angina and normal coronary angiogram,4 the left ventricle outside tract diameter was a predictor of developing DLVOTO. This parameter can be easily obtained by non-invasive tests such as conventional basal echocardiography and, such as has been previously suggested,6 could justify, at least if high blood pressure is present, the empiric use of beta-blockers as initial therapy.
Although the results showed by Zywica et al., such as the SAM of the mitral valve chordae at peak as predictor of dynamic obstruction, are of great interest, we think that the absence of measurement of the left ventricle outflow tract means an important limitation which could partially affect their conclusions.
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- Zywica K, Jenni R, Pellika PA, Faeh-Gunz A, Seifert B, Attenhofer Jost CH. Dynamic left ventricular outflow tract obstruction evoked by exercise Echocardiography: prevalence and predictive factors in prospective study. Eur J Echocardiogr (2008) 9:665–71.
[Abstract/Free Full Text] - Peteiro J, Lorenzo M, Castro-Beiras A. Labil subaortic obstruction during exercise stress echocardiography. Am J Cardiol (1999) 84:1119–23.[CrossRef][Web of Science][Medline]
- Cabrera-Bueno F, Rodriguez-Bailon I, Lopez-Salguero R, Gomez-Doblas JJ, Perez-Cabeza A, Peña_Hernandez JL, et al. Dynamic left ventricular outflow tract obstruction induced by exercise. Rev Esp Cardiol (2004) 57:1179–87.[CrossRef][Web of Science][Medline]
- Cabrera-Bueno F, Gomez-Doblas JJ, Muñoz-Garcia A, Garcia-Pinilla JM, Jimenez-Navarro MJ, de Teresa Galvan E. Effort angina, normal coronary angiogram, and dynamic left ventricular obstruction. J Am Soc Echocardiogr (2007) 20:415–20.[CrossRef][Web of Science][Medline]
- Henein MY, O'Sullivan C, Sutton GC, Gibson DG, Coats A. Stress induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly. J Am Coll Cardiol (1997) 30:1301–7.[Abstract]
- Cabrera-Bueno F, García-Pinilla JM, Gómez-Doblas JJ, Montiel-Trujillo A, Rodriguez-Bailon I, de Teresa-Galvan E. Beta-blocker therapy for dynamic left ventricular outflow tract obstruction induced by exercise. In J Cardiol (2007) 117:222–6.
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