From the Guidelines
Cardiac murmurs are graded on a scale of 1 to 6 based on their intensity during physical examination, with Grade 1 being very faint and Grade 6 being extremely loud. This grading system is crucial for clinicians to communicate the severity of murmurs and track changes over time 1. The intensity of a murmur is classified as follows:
- Grade 1 murmurs are very faint, barely audible even with careful listening
- Grade 2 murmurs are quiet but can be heard immediately
- Grade 3 murmurs are moderately loud without a thrill (vibration felt on palpation)
- Grade 4 murmurs are loud and accompanied by a palpable thrill
- Grade 5 murmurs are very loud and can be heard with the stethoscope partially off the chest, with an associated thrill
- Grade 6 murmurs are extremely loud and can be heard with the stethoscope entirely off the chest. When documenting murmurs, it's essential to note their timing (systolic or diastolic), location of maximum intensity, radiation pattern, quality (harsh, blowing, musical), and whether they change with respiration or position, as recommended by the American College of Cardiology/American Heart Association guidelines 1. The classification of murmurs is also critical, with different types of murmurs indicating various underlying cardiac conditions, such as holosystolic, midsystolic, early systolic, and late systolic murmurs 1.
The grading and classification of murmurs are vital for guiding further evaluation and management, including the use of echocardiography, which is recommended for asymptomatic patients with certain types of murmurs, such as diastolic murmurs, continuous murmurs, holosystolic murmurs, late systolic murmurs, and murmurs associated with ejection clicks or radiation to the neck or back 1. By accurately grading and classifying cardiac murmurs, clinicians can provide optimal care and improve patient outcomes.
From the Research
Grading of Heart Murmurs
The grading of heart murmurs is typically done on a scale of 1 to 6, with 1 being the faintest and 6 being the loudest 2. This grading system was developed by Samuel Levine and is still used today.
Characteristics of Murmurs
When evaluating heart murmurs, several characteristics should be noted, including:
- Location of maximal intensity of the murmur
- Intensity of the murmur itself
- Character of the murmur (blowing, rumbling, rough, or harsh)
- Transmission of the murmur
- Duration of the murmur and its time within the cardiac cycle 3
Examples of Murmur Grading
- A study found that approximately 20% of patients had grade 1 or 2 systolic murmurs, which were considered functional 2
- A case study reported a patient with a systolic murmur that was louder (Levine grade IV/VI) during expiration and diminished during inspiration (Levine grade I/VI) 4
- Innocent murmurs are typically minor (1/6 - 2/6), crescendo-decrescendo, mostly position-dependent, mid-systolic murmurs without radiation 5
Importance of Physical Examination
Physical examination skills, including auscultation of cardiac murmurs, are important for diagnosing and evaluating heart disease 5, 6. A detailed history and physical examination can help discriminate between innocent and organic murmurs.