2018 ESC guidelines for the management of cardiovascular diseases during preg- nancy. Eur Heart J. 2018;39:3165 241. 19. Whitlock RP, Sun JC, Fremes SE, et al. Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141:e576S 600S. 20. Vahanian A, Alfieri O, Andreotti F, et al. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J. 2012;33:2451 96. 21. Baumgartner H, Falk V, Bax JJ, et al. 2017 ESC/EACTS guidelines for the management of valvular heart disease. Eur Heart J. 2017;38:2739 91. 22. Yancy CW, Jessup M, Bozkurt B, et al. 2017 ACC/AHA/HFSA focused update of the 2013 ACCF/AHA guideline for the management of heart failure: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Failure Society of America. Circulation. 2017;136:e137 61. 1.5. Class of Recommendation and Level of Evidence 1. ACCF/AHA Task Force on Practice Guidelines. Methodology Manual and Policies From the ACCF/AHA Task Force on Practice Guidelines. American College of Cardiology and American Heart Association. 2010. Available at: https://professional.heart.org/-/media/phd-files/guidelines-and-state- August 19, 2020. 2. GENERAL PRINCIPLES 2.3. Diagnosis and Follow-Up 2.3.1. Diagnostic Testing: Initial Diagnosis 1. Baumgartner H, Hung J, Bermejo J, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. Eur J Echocardiogr. 2009;10:1 25. 2. Zoghbi WA, Adams D, Bonow RO, et al. Recommendations for noninva- sive evaluation of native valvular regurgitation: a report from the Ameri- can Society of Echocardiography. Developed in collaboration with the Society for Cardiovascular Magnetic Resonance. J Am Soc Echocardiogr. 2017;30:303 71. 3. Lancellotti P, Moura L, Pierard LA, et al. European Association of Echocar- diography recommendations for the assessment of valvular regurgitation. 