When we auscultate a systolic heart murmur, we need to describe its loudness or intensity. Some people use descriptive terms like 'soft' or 'loud', but traditionally the loudness of systolic murmurs is graded on a scale of 1 to 6. But what do the numbers mean?
The numeric system is sometimes called the Levine scale, named for Samuel A. Levine who first described it in 1933. The numbers correspond to the following intensities of murmur:
|The Levine scale of systolic murmur intensity|
In his original paper, Levine said that once physicians had worked with him for a short time, their gradings differed by no more than one gradation, and indeed were in "absolute agreement" in the majority of cases.
You can read more about Levine's grading of murmurs in the following paper:
Silverman ME, Wooley CF. Samuel A. Levine and the history of grading systolic murmurs. Am J Cardiol 2008; 102: 1107-1110.
You can also find Levine's original paper from 1933 here: