Spectral characteristics of mechanical heart valve closing sounds.

摘要: BACKGROUND AND AIMS OF THE STUDY: In-vivo evaluation of cavitation is based on the registration high-frequency pressure fluctuations that represent a mixture both and valve closing sounds, are difficult to separate. In order extract signal, high-pass filter removing sound applied. Importantly, cut-off frequency should be chosen valve's resonance pattern. This could determined in cavitation-free, air-operated set-up. As air water/blood have different physical properties influence frequencies, it necessary correlate content sounds recorded expected findings fluid. The study aim was characterize impact surrounding media source, develop method capable evaluating spectral characteristics mechanical heart valves. METHODS: Five valves were investigated. An in-vitro set-up developed where operated an airflow-controlled setting without cavitation. analysis performed. simple source also water evaluate media. RESULTS: Resonance frequencies from measured increased 14% compared with corresponding measurements water. These data used correct five showed air. at which 97.5% signal energy contained ranged 40.9 65.8 kHz. CONCLUSION: Using airflow model, possible determine signature might provide information needed design optimal when