How do you differentiate between valvular and non-valvular Atrial Fibrillation (AFib)?

Differentiating Between Valvular and Non-Valvular Atrial Fibrillation

The distinction between valvular and non-valvular atrial fibrillation is primarily based on the presence of moderate-to-severe mitral stenosis or mechanical heart valves, which are the only two conditions that define "valvular AF" according to current guidelines. 1

Current Definition of Valvular AF

• Valvular AF refers specifically to AF in the setting of:

  • Moderate-to-severe mitral stenosis (typically of rheumatic origin) 1, 2
  • Mechanical prosthetic heart valves 1

• Non-valvular AF encompasses all other forms of AF, including those with other types of valvular heart disease 1, 2

Important Clarifications

• The term "non-valvular AF" is misleading as it does not exclude patients with valvular heart disease other than moderate-to-severe mitral stenosis or mechanical heart valves 1

• Recent guidelines actually recommend abandoning the terms "valvular" and "non-valvular" AF due to confusion they cause 1

• The distinction was primarily created for determining eligibility for different anticoagulation strategies rather than describing the etiology of AF 2, 3

Clinical Assessment to Differentiate

To determine if AF is "valvular" or "non-valvular," focus on these key diagnostic elements:

1. Echocardiography findings:

   • Presence and severity of mitral stenosis 1, 2
   • Identification of mechanical prosthetic valves 1

2. Medical history:

   • History of rheumatic heart disease 1
   • Previous valve replacement surgery with mechanical prosthesis 1, 2

3. Physical examination:

   • Characteristic murmurs of mitral stenosis (diastolic rumble, opening snap) 4
   • Mechanical valve clicks 1

Clinical Implications

• Patients with valvular AF (moderate-to-severe mitral stenosis or mechanical heart valves) should receive vitamin K antagonists (warfarin) for anticoagulation 1

• Patients with non-valvular AF may receive either warfarin or NOACs (dabigatran, rivaroxaban, apixaban, or edoxaban) 1

• Other valvular conditions (mitral regurgitation, aortic stenosis, aortic regurgitation, bioprosthetic valves, valve repair) do not require exclusion from NOAC therapy 2, 3

Common Pitfalls to Avoid

• Misclassifying patients with mild mitral stenosis as having valvular AF 2, 5

• Incorrectly excluding patients with non-stenotic valvular disease (like mitral regurgitation or aortic valve disease) from NOAC therapy 2, 3

• Confusing bioprosthetic valves (which generally allow NOAC use after the initial post-operative period) with mechanical valves (which require warfarin) 3, 5

• Failing to recognize that the classification is primarily about anticoagulation strategy rather than the etiology of AF 2, 5