Systolic murmur (can be clinically significant or insignificant)
- Begin with or after S1 and end before or at S2
- Midsystolic – begins after S1 and ends before S2
- Pansystolic or holosystolic – begins after S1 and ends at S2
- Late systolic – starts in mid- or late systole and ends at S2
Diastolic murmur (are always clinically significant)
- Begin with or after S2 and end before or next S1
- Early diastolic murmur – begins right after S2 and ends before next S1
- Mid-diastolic – begins shortly after S2 and stops before next S1
- Late diastolic (presystolic) – begins in late diastole and stops at next S1
Continuous murmur (are always clinically significant)
- Begin in systole and continue without interruption through the timing of S2 into all or part of diastole.
Grade and description
- Very faint sounding murmur.
- Quiet sounding murmur that can be heard immediately after the placement of the stethoscope.
- Moderately loud sounding murmur.
- Loud sounding murmur.
- Very loud sounding murmur that can occasionally be heard when the stethoscope is only partially placed on the chest.
- Very loud murmur that can be heard when the stethoscope is entirely off the chest.
An organic murmur is pathologic, while a functional murmur is due to nonpathologic conditions. According to the 2007 American Heart Association’s Guidelines on Infective Endocarditis patients with organic murmurs do not need antibiotic prophylaxis.
According a Scientific Statement from the American Heart Association on May 18, 2021, there are no recommended changes to the 2007 viridans group streptococcal (VGS) infective endocarditis (IE) prevention guidelines. Therefore, antibiotic prophylaxis is not indicated for patients with heart murmurs associated with regurgitation.
Heart murmurs may be associated with conditions and diseases such as atrial fibrillation, left ventricular hypertrophy, systemic lupus erythematosus or other connective tissue disorders, right-sided congestive heart failure, or congenital heart disease.
Drug allergies may affect the type of medication used for antibiotic coverage.