How do you rate intensity of heart murmurs?
By tradition, murmurs are graded on a scale of 1 to 6 which was initially a research tool used for the study of systolic murmurs (Freeman & Levine, 1993) and is known as the Levine system.
| Grade | Intensity |
| Grade 1 | Faint; heard only with special effort |
| Grade 2 | Soft but readily detected |
| Grade 3 | Prominent but not loud |
| Grade 4 | Loud, accompanied by a thrill |
| Grade 5 | Very loud |
| Grade 6 | Loud enough to be heard with the stethoscope just removed from contact with the chest wall |
Levine system was initially developed for classifying benign vs. pathological (grade 3 or more) murmurs. However, there are limitations in terms of reproducibility and inter-rater reliability. More recently, it has been shown using heart sounds as an internal reference improved the reproducibility (Keren et al.)
| Grade | Intensity |
| Grade 1 | Clearly softer than the heart sounds |
| Grade 2 | Approximately equal in intensity to the heart sounds |
| Grade 3 | Clearly louder than the heart sounds, but no thrill |
| Grade 4 | Associated with a thrill by palpation |
| Grade 5 | Heard with one edge of the stethoscope lifted |
| Grade 6 | Heard with both edges of the stethoscope lifted |
Freeman AR, Levine SA: Clinical significance of systolic murmurs: Study of 1000 consecutive “noncardiac” cases. Ann Intern Med 6: 1371-1379. 1933.
Keren R, Tereschuk M, Luan X. Evaluation of a novel method for grading heart murmur intensity. Arch Pediatr Adolesc Med. 2005 Apr; 159(4):329-34.
