Intensity and Grade Heart Murmurs

Intensity of heart murmurs is graded on an objective scale, expressed as a fraction. The numerator describes the intensity where it's loudest, while the denominator indicates the scale used. Factors influencing intensity include:

Chest wall thickness
- Presence of intervening tissue
- Body composition (thin vs. muscular/obese)
- Lung condition (e.g., emphysema can diminish intensity)

Grading Systems:

Murmur Type	Scale	Notes
Systolic	6-point (Levine)	Grades 4-6 require palpable thrill
Diastolic	4-point	Rarely associated with palpable thrill

Systolic Murmur Grading (Levine system):

Grade	Description
1/6	Softer than S1 and S2, very faint
2/6	Equal to S1 and S2, quiet but immediately audible
3/6	Louder than S1 and S2, moderately loud
4/6	Louder than S1 and S2, with palpable thrill
5/6	Louder than S1 and S2, with thrill; audible with stethoscope partly off chest
6/6	Louder than S1 and S2, with thrill; audible with stethoscope entirely off chest

Diastolic Murmur Grading:

Grade	Description
1/4	Barely audible, very faint
2/4	Soft but clearly audible
3/4	Moderately loud
4/4	Very loud, may be associated with a thrill

For additional maneuvers, refer to Special Techniques, pp. 528–529.

graph TD
    A[Heart Murmur] --> B{Systolic or Diastolic?}
    B -->|Systolic| C[Use 6-point Levine scale]
    B -->|Diastolic| D[Use 4-point scale]
    C --> E{Palpable thrill?}
    E -->|Yes| F[Grade 4-6]
    E -->|No| G[Grade 1-3]
    D --> H[Grade 1-4]