A Cabot–Locke murmur is an early
diastolic heart murmur
Diastolic heart murmurs are heart murmurs heard during diastole, i.e. they start at or after S2 (heart sound), S2 and end before or at S1 (heart sound), S1. Many involve stenosis of the Heart valve#Atrioventricular valves, atrioventricular valves ...
, occasionally heard in severe untreated
anemia, without
heart valve abnormalities.
[''The Journal of the American Medical Association''. 1903 Volume 40, Part 2, 1539] It is detected infrequently, is best heard at the left sternal border, and sounds similar to
aortic insufficiency, although it is without
decrescendo. Its location, timing, association with severe anemia, and resolution upon correction of anemia, are consistent mechanistically with a
functional murmur
A functional murmur (innocent murmur, physiologic murmur) is a heart murmur that is primarily due to physiologic conditions outside the heart, as opposed to structural defects in the heart itself. Serious conditions can arise even in the absence of ...
arising from high volume
flow dynamics in the
left main coronary artery
The left coronary artery (LCA) is a Coronary arteries, coronary artery that arises from the aorta above the left cusp of the aortic valve, and feeds blood to the left side of the heart muscle. It is also known as the left main coronary artery (LMC ...
, which has almost entirely diastolic flow.
It is named for
Richard Clarke Cabot and his colleague, Locke. They reported on a series of three patients who had been clinically diagnosed with heart valve disease, but who had normal valvular anatomy at subsequent autopsy.
References
Heart murmurs
{{med-sign-stub