title: Relationship between mitral regurgitation and left ventricular outflow obstruction in hypertrophic cardiomyopathy.
abstract: To clarify the relationship between mitral regurgitation and left ventricular outflow obstruction, Doppler and two-dimensional echocardiographic studies were performed in 62 patients with hypertrophic cardiomyopathy (22 with and 40 without obstruction caused by mitral systolic anterior motion with septal contact). Pulsed Doppler echocardiography with color Doppler flow imaging demostrated that in 20 of the 22 patients with obstruction, mitral regurgitation occurred mainly during midsystole from the onset to the end of mitral-septal contact. Such midsystolic mitral regurgitation was not observed in patients without obstruction, except in three of 25 patients with mild mitral systolic anterior motion without septal contact. Furthermore, that regurgitation developed or disappeared together with the obstruction during follow-up periods or pharmacologic interventions. Two-dimensional echocardiography showed that in 21 of the 22 patients with obstruction, a distal residual portion of the "anterior" mitral leaflet moved anteriorly in early systole and protruded into the outflow tract during midsystole to cause the obstruction. In the other patient with obstruction, who had only early systolic mitral regurgitation, a distal residual "posterior" leaflet moved similary. These results may indicate that the midsystolic mitral regurgitation is hydrodynamically induced by the midsystolic pressure gradient across the protruding distal residual anterior mitral leaflet.
authors.affiliation: Second Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: I
authors.initials: I
authors.lastname: Hasegawa
authors.forename: T
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Hada
authors.forename: K
authors.initials: K
authors.lastname: Takenaka
authors.forename: K
authors.initials: K
authors.lastname: Amano
authors.forename: H
authors.initials: H
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: J
authors.initials: J
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Shiota
authors.forename: T
authors.initials: T
authors.lastname: Sugimoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000503:physiopathology; D015150:Echocardiography, Doppler; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D014694:Ventricular Outflow Obstruction / Q000150:complications*