Section 870.2390 - Phonocardiograph(a)Identification. A phonocardiograph is a device used to amplify or condition the signal from a heart sound transducer. This device furnishes the excitation energy for the transducer and provides a visual or audible display of the heart sounds.(b)Classification. Class I (general controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 870.9 .45 FR 7907, Feb. 5, 1980, as amended at 61 FR 1121, Jan. 16, 1996; 66 FR 38796 , July 25, 2001