title: Easy method for measurement of opening angle of Björk-Shiley valve with two computers. Proof of floating phenomenon of Björk-Shiley valve.
abstract: A new method for measuring the opening angle of Björk-Shiley valve (B-S valve) was reported in 1977. However, this method is complicated enough to permit quick calculation of the opening angle in multiple frames of one cinefilm. We devised a new method with using two computers (NAC Cardias GP 2000, TEXAS TI-59) for calculating the opening angle of the B-S valve. We measured the opening angle of 7 cases (they were all implanted B-S valves, 5 were mitral and 2 were aortic). Results are the following: (1) The maximum opening angle ranged from 54 degrees to 65 degrees and the mean value was 58.1 degrees. (2) We showed the floating phenomenon of B-S valve with our method. (3) We showed the accuracy of our method by measuring 10 times the same photograph of B-S valve. (4) We showed that our method is very accurate by comparing the values calculated by our method with those calculated directly from the valve which was removed from a patient. (5) It takes less than 30 minutes to calculate the opening angle of 60 frames (we took 60 frames of cine-film per minutes.
mesh_terms: D001021:Aortic Valve; D001281:Atrial Fibrillation / Q000175:diagnosis; D003201:Computers; D006333:Heart Failure / Q000175:diagnosis; D006350:Heart Valve Prosthesis; D006801:Humans; D007565:Jaundice / Q000175:diagnosis; D008943:Mitral Valve; D008944:Mitral Valve Insufficiency / Q000175:diagnosis