From the Guidelines
Mitral regurgitation is characterized by a holosystolic murmur, which is typically high-pitched and blowing in quality, best heard at the apex of the heart. This type of murmur is a result of the pressure gradient driving blood backward from the left ventricle into the left atrium through the incompetent mitral valve, creating the characteristic sound 1. The murmur begins with the first heart sound (S1) and continues throughout systole until the second heart sound (S2), without any gap. Some key points to consider when evaluating mitral regurgitation include:
- The intensity of the murmur correlates with the severity of regurgitation, though this correlation is not perfect 1
- In acute mitral regurgitation, the murmur may be shorter or less intense due to rapid equalization of pressures between the left ventricle and left atrium
- Associated findings may include a displaced apical impulse and, in severe cases, a third heart sound (S3) 1
- The holosystolic nature of the murmur is a key characteristic of mitral regurgitation, and it is essential to distinguish it from other types of murmurs to determine the underlying cause and appropriate management.
From the Research
Mitral Regurgitation Murmur Types
- The type of murmur associated with mitral regurgitation can be either pan-systolic or late-systolic, as noted in a study published in The American journal of the medical sciences 2.
- A pan-systolic murmur is typically associated with more significant hemodynamic consequences, while a late-systolic murmur may also be associated with adverse left ventricular remodeling, despite being widely believed to represent regurgitation of a degree that is not associated with hemodynamic significance 2.
Characteristics of Mitral Regurgitation Murmurs
- The late-systolic murmur of mitral regurgitation is characterized by its timing, which can be verified by cine magnetic resonance imaging 2.
- The extent of left ventricular remodeling associated with the late-systolic murmur has been systematically assessed in a study of 82 patients with at least moderate isolated mitral regurgitation 2.
- The study found that both pan-systolic and late-systolic murmur groups had significant left ventricular remodeling, as evidenced by increased left ventricular end-diastolic volume index compared to normals 2.
Clinical Implications
- The type of murmur associated with mitral regurgitation can have important clinical implications, as it may influence the management and treatment of the condition 2.
- Further research is needed to fully understand the relationship between murmur type and clinical outcomes in patients with mitral regurgitation, as well as the potential benefits of various treatments, such as ACE inhibitors and beta-blockers 3, 4, 5, 6.