System for acquisition of weak murmurs related to coronary artery diseases

The aim of the present study is to describe the design of an acquisition system for the specific purpose of recording heart murmurs originating from stenosis in the coronary arteries. The design and development of such a system require knowledge in many disciplines: acoustic couplers, microphones, skin adhesives, electronic hardware, software and patient safety. Special considerations are needed in order to record these murmurs since they have a 60 dB lower sound level, than that of the closing heart valves. The system was implemented and successfully used for collection of heart sounds in a clinical trial including 463 patients referred for elective coronary angiography.