Act of listening for sounds within the heart.
Graphic registration of the heart sounds picked up as vibrations and transformed by a piezoelectric crystal microphone into a varying electrical output according to the stresses imposed by the sound waves. The electrical output is amplified by a stethograph amplifier and recorded by a device incorporated into the electrocardiograph or by a multichannel recording machine.
Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.