Abstract
OBJECTIVE--To compare the effect of exercise on pressure half time in patients with mechanical or bioprosthetic mitral valves. A relative pressure half time (pressure half time as a percentage of RR interval) was used in an attempt to correct for the shortening of the diastolic time interval caused by the increase in heart rate during exercise and thus to uncover the effects of valve design on pressure half time during exercise. PATIENTS--Twenty clinically stable (New York Heart Association grade I-II) patients with mechanical (n = 12) or bioprosthetic (n = 8) mitral valves (median age 51) years. The median time since valve replacement was 42 months. METHODS--Continuous wave Doppler echocardiography from the apical view at rest and during moderate supine bicycle exercise (50 W). RESULTS--During exercise the mean (SD) heart rate increased from 79 (12) to 101 (12) beats per minute (95% confidence interval (95% CI) of difference, 15 to 29/min) and the peak pressure gradient from 11 (5) to 18 (6) mm Hg (95% CI of difference 5 to 9 mm Hg). The pressure half time decreased from 114 (30) to 78 (26) ms (95% CI of difference (30-42 ms). There was no difference between the valve types. The relative pressure half time remained unchanged in patients with mechanical valves during exercise (13 (4) rest and 13 (5)% exercise, respectively) and decreased in patients with bioprostheses (17 (3) and 12 (3)%, respectively (95% CI of difference 2 to 8%, p = 0.025). CONCLUSIONS--In patients with mechanical mitral valves the decrease in the pressure half time during exercise is probably mostly the result of the shortening of the diastolic time interval with increasing heart rate whereas in patients with bioprosthetic valves an increase in functional valve area may contribute to the shortening of pressure half time during exercise.
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Selected References
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- Alam M., Rosman H. S., Lakier J. B., Kemp S., Khaja F., Hautamaki K., Magilligan D. J., Jr, Stein P. D. Doppler and echocardiographic features of normal and dysfunctioning bioprosthetic valves. J Am Coll Cardiol. 1987 Oct;10(4):851–858. doi: 10.1016/s0735-1097(87)80280-2. [DOI] [PubMed] [Google Scholar]
- Chambers J. B., Cochrane T., Black M. M., Jackson G. The Gorlin formula validated against directly observed orifice area in porcine mitral bioprostheses. J Am Coll Cardiol. 1989 Feb;13(2):348–353. doi: 10.1016/0735-1097(89)90510-x. [DOI] [PubMed] [Google Scholar]
- Chambers J., Jackson G., Jewitt D. Limitations of Doppler ultrasound in the assessment of the function of prosthetic mitral valves. Br Heart J. 1990 Mar;63(3):189–194. doi: 10.1136/hrt.63.3.189. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chambers J., McLoughlin N., Rapson A., Jackson G. Effect of changes in heart rate on pressure half time in normally functioning mitral valve prostheses. Br Heart J. 1988 Dec;60(6):502–506. doi: 10.1136/hrt.60.6.502. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cosgrove D. M., Lytle B. W., Gill C. C., Golding L. A., Stewart R. W., Loop F. D., Williams G. W. In vivo hemodynamic comparison of porcine and pericardial valves. J Thorac Cardiovasc Surg. 1985 Mar;89(3):358–368. [PubMed] [Google Scholar]
- Dumesnil J. G., Honos G. N., Lemieux M., Beauchemin J. Validation and applications of mitral prosthetic valvular areas calculated by Doppler echocardiography. Am J Cardiol. 1990 Jun 15;65(22):1443–1448. doi: 10.1016/0002-9149(90)91352-7. [DOI] [PubMed] [Google Scholar]
- Ishimaru S., Furuawka K., Takahashi M. Cineradiographic evaluation of the convexo-concave Björk-Shiley prosthetic valve in mitral position. Scand J Thorac Cardiovasc Surg. 1983;17(3):211–215. doi: 10.3109/14017438309099354. [DOI] [PubMed] [Google Scholar]
- Kapur K. K., Fan P., Nanda N. C., Yoganathan A. P., Goyal R. G. Doppler color flow mapping in the evaluation of prosthetic mitral and aortic valve function. J Am Coll Cardiol. 1989 Jun;13(7):1561–1571. doi: 10.1016/0735-1097(89)90350-1. [DOI] [PubMed] [Google Scholar]
- Rashtian M. Y., Stevenson D. M., Allen D. T., Yoganathan A. P., Harrison E. C., Edmiston W. A., Faughan P., Rahimtoola S. H. Flow characteristics of four commonly used mechanical heart valves. Am J Cardiol. 1986 Oct 1;58(9):743–752. doi: 10.1016/0002-9149(86)90349-8. [DOI] [PubMed] [Google Scholar]
- Rashtian M. Y., Stevenson D. M., Allen D. T., Yoganathan A. P., Harrison E. C., Edmiston W. A., Rahimtoola S. H. Flow characteristics of bioprosthetic heart valves. Chest. 1990 Aug;98(2):365–375. doi: 10.1378/chest.98.2.365. [DOI] [PubMed] [Google Scholar]
- Reisner S. A., Lichtenberg G. S., Shapiro J. R., Schwarz K. Q., Meltzer R. S. Exercise Doppler echocardiography in patients with mitral prosthetic valves. Am Heart J. 1989 Oct;118(4):755–759. doi: 10.1016/0002-8703(89)90589-9. [DOI] [PubMed] [Google Scholar]
- Scotten L. N., Racca R. G., Nugent A. H., Walker D. K., Brownlee R. T. New tilting disc cardiac valve prostheses. In vitro comparison of their hydrodynamic performance in the mitral position. J Thorac Cardiovasc Surg. 1981 Jul;82(1):136–146. [PubMed] [Google Scholar]
- Thomas J. D., Weyman A. E. Doppler mitral pressure half-time: a clinical tool in search of theoretical justification. J Am Coll Cardiol. 1987 Oct;10(4):923–929. doi: 10.1016/s0735-1097(87)80290-5. [DOI] [PubMed] [Google Scholar]
- Verdel G., Heethaar R. M., Jambroes G., van der Werf T. Assessment of the opening angle of implanted Björk-Shiley prosthetic valves. Circulation. 1983 Aug;68(2):355–359. doi: 10.1161/01.cir.68.2.355. [DOI] [PubMed] [Google Scholar]
- Wilkins G. T., Gillam L. D., Kritzer G. L., Levine R. A., Palacios I. F., Weyman A. E. Validation of continuous-wave Doppler echocardiographic measurements of mitral and tricuspid prosthetic valve gradients: a simultaneous Doppler-catheter study. Circulation. 1986 Oct;74(4):786–795. doi: 10.1161/01.cir.74.4.786. [DOI] [PubMed] [Google Scholar]
