Mitral valve repair available in Europe but still in clinical trial in the United States. It is a highly specialized technique only available at select hospitals. Early trial results suggest that it may be a beneficial approach for patients who are at high risk from conventional surgery. As early as January 2000 a team of doctors at the "Instituto de Cardiología y Cirugía Cardiovascular" in La Habana, Cuba have performed beating heart mitral valve repair or replacement. The beating heart mitral valve replacement technique is as safe as the arrested heart technique, and is the recommended alternative to arrested heart technique. The analogy
Mitral valve prolapse "atrialis", "fibrosa", and "spongiosa". Patients with classic mitral valve prolapse have excess connective tissue that thickens the spongiosa and separates collagen bundles in the fibrosa. This is due to an excess of dermatan sulfate, a glycosaminoglycan. This weakens the leaflets and adjacent tissue, resulting in increased leaflet area and elongation of the chordae tendineae. Elongation of the chordae tendineae often causes rupture, commonly to the chordae attached to the posterior leaflet. Advanced lesions—also commonly involving the posterior leaflet—lead to leaflet folding, inversion, and displacement toward the left atrium. Echocardiography is the most useful method of diagnosing a prolapsed mitral valve.