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08/15/2011 - cardiac murmurs

posted Sep 28, 2011, 5:05 PM by Chief Resident   [ updated Sep 28, 2011, 6:31 PM by Purnema Madahar ]
Welcome to the third week on the floors!

This morning during intake, I stumbled over the characterization of a cardiac murmur Amit Patel had beautifully described and correctly interpreted as mitral valve regurgitation. For those that were present: MR does decrease in intensity during the strain phase of a Valsalva maneuver.

More generally, most systolic murmurs decrease with Valsalva with the exception of hypertrophic cardiomyopathy, in which the murmur increases, according to the attached paper with a sensitivity of 65% and a specificity of 96%, determined in a population enriched with known cardiac murmurs and compared to the gold standard of echo or angiogram.

The paper is a great read, even just for the methodology section: have a good laugh at the section on blinding. Key findings were nicely summarized by someone at the University of Washington:

Nicholas Lembo, Louis Dell'Italia, Michael Crawford, Robert O'Rourke (1988)
New England Journal of Medicine 318 (24) p. 1573-1578