From the Research
The murmur associated with anemia is typically a systolic flow murmur, characterized as soft and blowing, with a grade 1-2/6 intensity, and is best heard at the left sternal border or over the pulmonic area. This type of murmur occurs due to decreased blood viscosity and increased cardiac output that develops in anemic states, as noted in a study on the pathophysiology of anemia 1. When hemoglobin levels fall, blood becomes less viscous, allowing for faster flow through the heart chambers and great vessels, which creates turbulence heard as a murmur.
The characteristics of this murmur can be distinguished from pathological murmurs by its soft quality, timing in systole, absence of radiation to other areas, and its association with other signs of anemia such as pallor, fatigue, and tachycardia. A study from 2005 2 found that in patients with iron-deficiency anemia, systolic heart murmurs were common, and these murmurs resolved after iron therapy was administered, indicating that the murmur is usually benign and resolves when the underlying anemia is corrected.
Key points about the murmur of anemia include:
- It is a systolic flow murmur
- Typically soft and blowing
- Grade 1-2/6 in intensity
- Best heard at the left sternal border or over the pulmonic area
- Occurs due to decreased blood viscosity and increased cardiac output in anemic states
- Resolves when the underlying anemia is corrected
- Can be distinguished from pathological murmurs by its characteristics and association with anemia symptoms
Clinicians should be aware that the presence of this murmur in a patient with unexplained symptoms should prompt evaluation of hemoglobin levels and investigation into the cause of potential anemia, as highlighted in a study on the evaluation of clinical pallor in identifying and treating children with moderate and severe anemia 3.