Because of a lapse in government funding, the information on this
website may not be up to date, transactions submitted via the
website may not be processed, and the agency may not be able to
respond to inquiries until appropriations are enacted. The NIH
Clinical Center (the research hospital of NIH) is open. For more
details about its operating status, please visit
cc.nih.gov. Updates
regarding government operating status and resumption of normal
operations can be found at
opm.gov.
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.
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.