An old mitral regurgitant murmur is useful for this purpose.
"Aids to Forensic Medicine and Toxicology"
W. G. Aitchison Robertson
Examine the mitral valve from above.
"Physiology and Hygiene for Secondary Schools"
Francis M. Walters, A.M.
There's a slight murmur-mitral valves a little worn, perhaps; but they'll last your time if you're careful.
"The Philanderer"
George Bernard Shaw