Table 1. Etiology: main differences between fibro-elastic deficiency and Barlow’s disease in degenerative MR.

Criteria	Fibro-elastic deficiency	Barlow
Pathology	Thin leaflets (no prolapsed area)	Redundant leaflets (>5 mm)
	Disrupted elastin and rare collagen	Myxoid degeneration
Age	Old adult (>60 years)	Young adult (<60 years)
History of murmur	Recent	Long lasting—familial
Echocardiography	No excess of tissue (A2 ≤34 mm)	Excess of tissue (A2 ≥34 mm)
	Post-leaflet (P2) prolapse	Bileaflet prolapse
	Chordal rupture	Billowing—MAD
Surgery	Repair+++	Repair+++
	Replacement if fragile tissue	Single and large annuloplasty—risk of SAM+

MAD, mitral annular disjunction; MR, mitral regurgitation; SAM, systolic anterior motion.