High-Sensitivity Capacitance Pickup for Heart Sounds and Murmurs

Exploration of heart murmur frequencies requires a pickup and associated electronics having great sensitivity and a wide range. Such a system, employing a capacitance principle, has been applied to reproduction of sounds from the precordium. The pickup is of the direct contact type, is relatively insensitive to extraneous noise, and is capable of recording murmurs of extremely low intensity.