Can a Heart Murmur Due to Polycythemia Vera Disappear?
Yes, a heart murmur caused by polycythemia vera can disappear with appropriate treatment that reduces blood viscosity and normalizes hematocrit levels. 1
Mechanism of Murmur Development in PV
Polycythemia vera causes increased red blood cell mass, leading to hyperviscosity and increased blood volume. 2 This creates turbulent blood flow across cardiac valves and through vessels, producing functional (flow) murmurs rather than structural valve abnormalities. These are typically systolic ejection murmurs that result from the increased stroke volume and altered blood rheology. 3
Treatment-Induced Resolution
Primary Therapeutic Interventions
Phlebotomy to maintain hematocrit strictly below 45% is the cornerstone of treatment and directly addresses the hyperviscosity that generates the murmur. 1, 4
Cytoreductive therapy with hydroxyurea or interferon-α for high-risk patients (age >60 years or history of thrombosis) further reduces blood cell counts and viscosity. 1, 2
As hematocrit normalizes through phlebotomy and blood viscosity decreases, the turbulent flow that created the murmur resolves, and the murmur typically disappears or significantly diminishes. 1
Expected Timeline
Murmur intensity should decrease progressively as hematocrit is brought down to target levels (typically <45% in men, approximately 42% in women). 1
Complete resolution may occur within weeks to months of achieving and maintaining target hematocrit levels, though this varies by individual. 3
Clinical Monitoring
The presence or absence of the murmur can serve as a clinical indicator of disease control, though hematocrit levels remain the primary monitoring parameter. 3
Follow-up visits at 2-4 month intervals for well-controlled PV allow assessment of both hematocrit maintenance and resolution of physical findings like murmurs. 3
Important Caveats
If a murmur persists despite adequate hematocrit control, consider alternative etiologies including pre-existing structural valve disease unrelated to PV. 3
Extreme thrombocytosis (platelet count >1,500 × 10⁹/L) may require additional cytoreductive therapy even if hematocrit is controlled, as this can contribute to cardiovascular symptoms. 1, 2
The murmur's disappearance does not eliminate the need for continued treatment, as the underlying myeloproliferative disorder persists and requires lifelong management. 5, 2