The Level of Evidence (LOE) rates the quality of scientific evidence supporting the intervention on the basis of the type, quantity, and consistency of data from clinical trials and other sources (Table 2).1 Table 1. Associated Guidelines and Related References Title Organization Publication Year (Reference) Recommendations for Evaluation of the Severity of Native Valvular Regurgitation With Two-Dimensional and Doppler Echocardiography European Association of Echocardiography Recommendations for the Assessment of Valvular Regurgitation, Part 2: Mitral and Tricuspid Regurgitation (Native Valve Disease) Guidelines for the Management of Patients With Atrial Fibrillation ACC/AHA/ESC 2006, 2008, 20197 9 Guidelines for the Management of Adults With Congenital Heart Disease ACC/AHA 201810 Echocardiographic Assessment of Valve Stenosis: EAE/ASE Recommendations for Clinical Practice EAE/ASE 200911 Recommendations on the Echocardiographic Assessment of Aortic Valve Stenosis: A Focused Update from the European Association of Cardiovascular Imaging and the American Society of Echocardiography Guidelines for the Evaluation of Valvular Regurgitation After Percutaneous Valve Repair or Replacement: A Report from the American Society of Echocardiography Recommendations for Evaluation of Prosthetic Valves With Echocardiography and Doppler Ultrasound ASE 200914 Guideline for the Diagnosis and Treatment of Hypertrophic Cardiomyopathy ACCF/AHA 201115 Guidelines on the Management of Cardiovascular Diseases During Pregnancy ESC 2011, 201817, 18 Antithrombotic and Thrombolytic Therapy for Valvular Disease: Antithrombotic Therapy and Prevention of Thrombosis ACCP 201219 Guidelines on the Management of Valvular Heart Disease ESC/EACTS 201220 Guideline for the Management of Heart Failure ACCF/AHA 201722 ACC indicates American College of Cardiology; ACCF, American College of Cardiology Foundation; ACCP, American College of Chest Physicians; AHA, American Heart Association; ASE, American Society of Echocardiography; EACI, European Association of Cardiovascular Imaging; EACTS, European Association of Cardio Thoracic Surgery; EAE, European Association of Echocardiography; and ESC, European Society of Cardiology. 