Echocardiographic Characteristics of Severe Left Ventricular Outflow Tract Obstruction in Hypertrophic Cardiomyopathy

It is important to diagnose severe left ventricular outflow tract (LVOT) obstruction in symptomatic patients with hypertrophic cardiomyopathy (HCM) to determine who might benefit from septal reduction therapy. Due to its dynamic nature, LVOT obstruction may not be present at rest, 1 Maron M.S. Olivotto I. Betocchi S. Casey S.A. Lesser J.R. Losi M.A. et al. Effect of left ventricular outflow tract obstruction on clinical outcome in hypertrophic cardiomyopathy. New Engl J Med. 2003; 348: 295-303 Crossref PubMed Scopus (1012) Google Scholar , 2 Maron M.S. Olivotto I. Zenovich A.G. Link M.S. Pandian N.G. Kuvin J.T. et al. Hypertrophic cardiomyopathy is predominantly a disease of left ventricular outflow tract obstruction. Circulation. 2006; 114: 2232-2239 Crossref PubMed Scopus (650) Google Scholar , 3 Ayoub C. Geske J.B. Larsen C.M. Scott C.G. Klarich K.W. Pellikka P.A. Comparison of Valsalva maneuver, amyl nitrite, and exercise echocardiography to demonstrate latent left ventricular outflow obstruction in hypertrophic cardiomyopathy. Am J Cardiol. 2017; 120: 2265-2271 Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar and it is then necessary to “search for obstruction” with further provocative testing. 4 Ommen S.R. Mital S. Burke M.A. Day S.M. Deswal A. Elliott P. et al. 2020 AHA/ACC guideline for the diagnosis and treatment of patients with hypertrophic cardiomyopathy: a report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. J Am Coll Cardiol. 2020; 76: e159-e240 Crossref PubMed Scopus (76) Google Scholar , 5 Geske J.B. Sorajja P. Ommen S.R. Nishimura R.A. Left ventricular outflow tract gradient variability in hypertrophic cardiomyopathy. Clin Cardiol. 2009; 32: 397-402 Crossref PubMed Scopus (54) Google Scholar , 6 Nishimura R.A. Ommen S.R. Hypertrophic cardiomyopathy: the search for obstruction. Circulation. 2006; 114: 2200-2202 Crossref PubMed Scopus (41) Google Scholar We sought to determine whether there are resting echocardiographic characteristics associated with latent LVOT obstruction.