Does the mitral regurgitation (MR) murmur become louder or quieter when a patient is in the left lateral decubitus (LLD) position?

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Last updated: March 26, 2025View editorial policy

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From the Guidelines

The murmur of mitral regurgitation typically becomes louder when the patient is in the left lateral decubitus position. This occurs because in the left lateral position, the heart is brought closer to the chest wall, which enhances the transmission of the murmur to the stethoscope. Additionally, this position increases venous return to the heart, which can augment the volume of regurgitant blood flow through the incompetent mitral valve.

The mitral regurgitation murmur is usually best heard at the apex of the heart (fifth intercostal space, midclavicular line) and is characterized as a holosystolic murmur that may radiate to the axilla. When examining a patient with suspected mitral regurgitation, having them turn to the left lateral decubitus position while auscultating can help confirm the diagnosis by making the murmur more prominent. This positioning technique is a valuable clinical tool that can help distinguish mitral regurgitation from other cardiac murmurs that may not be similarly affected by positional changes, as discussed in the context of valvular heart disease management 1.

Some key points to consider when evaluating mitral regurgitation include:

  • The severity of the MR is related to the magnitude of the regurgitant volume, which results in LV dilation and increases in left atrial pressure and volume 1.
  • Echocardiography is a crucial diagnostic modality for patients with valvular heart disease, but it should be used in conjunction with a meticulous history and physical examination to establish a pre-test probability of the severity of the valve lesion 1.
  • The physical examination is essential in the evaluation of patients with valvular heart disease, as it can help identify discrepancies in the echocardiographic report and provide a more accurate assessment of the severity of mitral regurgitation.

Overall, the left lateral decubitus position is a useful technique for enhancing the murmur of mitral regurgitation and aiding in the diagnosis of this condition.

From the Research

Mitral Regurgitation Murmur Characteristics

  • The provided studies do not directly address how the mitral regurgitation (MR) murmur changes when a patient is in the left lateral decubitus (LLD) position 2, 3, 4, 5, 6.
  • These studies focus on the diagnosis, management, and treatment of mitral regurgitation, including its causes, symptoms, and the role of echocardiography in assessing severity and guiding therapy 2, 3, 4, 5.
  • One study discusses "silent" severe mitral regurgitation, where patients may not exhibit the typical audible systolic murmur despite having hemodynamically significant mitral regurgitation 6.
  • None of the studies specifically mention the effect of patient position, such as the left lateral decubitus position, on the loudness of the MR murmur 2, 3, 4, 5, 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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