Voice reduction in cardiac auscultation sounds with reference signals measured from vocal resonators.

This study proposes the use of vocal resonators to enhance cardiac auscultation signals and evaluates their performance for voice-noise suppression. Data were collected using two electronic stethoscopes while each study subject was talking. One collected auscultation signal from the chest while the other collected voice signals from one of the three voice resonators (cheek, back of the neck, and shoulder). The spectral subtraction method was applied to the signals. Both objective and subjective metrics were used to evaluate the quality of enhanced signals and to investigate the most effective vocal resonator for noise suppression. Our preliminary findings showed a significant improvement after enhancement and demonstrated the efficacy of vocal resonators. A listening survey was conducted with thirteen physicians to evaluate the quality of enhanced signals, and they have received significantly better scores regarding the sound quality than their original signals. The shoulder resonator group demonstrated significantly better sound quality than the cheek group when reducing voice sound in cardiac auscultation signals. The suggested method has the potential to be used for the development of an electronic stethoscope with a robust noise removal function. Significant clinical benefits are expected from the expedited preliminary diagnostic procedure.

Suture tie-down forces and cyclic contractile forces after undersized tricuspid annuloplasty using a Tri-Ad Adams tricuspid annuloplasty ring in an ovine model.

OBJECTIVES: This study evaluated suture tie-down forces and cyclic contractile forces (CCFs) after undersized tricuspid annuloplasty using a hybrid band. METHODS: Downsized tricuspid annuloplasty was planned in adult male sheep using 8 force transducers attached from the septal to the anterior annular areas of the ring (segments 1 and 2, flexible septal; segments 3 and 4, semi-rigid posterior; segments 5 and 6, semi-rigid anterior; segments 7 and 8, flexible anterior). CCFs were analysed at 3 different levels of peak right ventricular pressure (RVP): 30, 50 and 70 mmHg. RESULTS: Eight 5-year-old male Corriedale sheep (average body weight = 66.8 kg) were used. The average suture tie-down force was 4.42 [standard deviation (SD): 2.32] N. When the forces were compared, it was lowest in the flexible anterior area and highest in the flexible septal area (P < 0.001). With the RVP of 30 mmHg, the average CCFs was lowest at segment 3 [0.07 (SD: 0.07) N] and highest at segment 7 [0.15 (SD: 0.08) N]. The CCFs were 0.12 (SD: 0.1) N, 0.09 (SD: 0.12) N, 0.14 (SD: 0.1) N and 0.13 (SD: 0.09) N in the flexible septal, semi-rigid posterior, semi-rigid anterior and flexible anterior parts, respectively (P = 0.208). As the peak RVP increased to 50 and 70 mmHg, the CCFs of each area increased significantly (P < 0.001). Despite this increase, the CCFs remained low (0.1 and 0.3 N), and differences in CCFs between segments and between annular areas showed similar patterns. CONCLUSIONS: The flexible end of the hybrid band reduces the CCFs and might prevent annular tears after ring tricuspid annuloplasty, and the risk of tear would be low even in the septal area.