| Popis: |
Two main theories exist concerning the origin of the heart sounds. The first proposes that rapid pressure fluctuations cause the cardiac valve leaflets to vibrate and produce the sound. The second theory suggests that sudden pressure perturbations cause the entire cardiohemic mass to vibrate as a whole. In 35 patients (26 men and 9 women, aged 18 to 73) with various heart diseases microtransducer catheters (Millar) were used to simultaneously record aortic pressures and aortic internal phonocardiograms in order to determine if they had a common mode of origin and propagation. The propagation velocities of the first heart sound and the foot of the aortic pressure pulse were found to be similar, 5.24 +/- 0.61 m/s and 5.97 +/- 1.87 m/s respectively (+/- SE). It was possible to derive facsimiles of the aortic internal phonocardiogram by double differentiation of the corresponding aortic pressure pulse and conversely to derive the pressure pulse by double integration of the phonocardiogram. These data support the concept that the low-frequency pressure variations produced by the entire cardiohemic mass, which predominate in the aortic pressure pulse waveforms, are generated and propagated in the same manner as the high-frequency pressure variations, which are the first and second heart sounds. |
