What is the significance of a whistling sound at the end of S1 and S2 (first and second heart sounds)?

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Last updated: April 28, 2025View editorial policy

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From the Guidelines

Whistling at the end of S1 and S2 heart sounds is most likely an innocent flow murmur, which is common and typically benign. These murmurs are caused by blood flowing through normal heart structures at higher velocities, creating audible vibrations 1. No specific treatment is needed for innocent murmurs, but if you're experiencing symptoms like chest pain, shortness of breath, dizziness, or fainting, you should seek medical evaluation.

Key Points to Consider

  • A cardiologist can distinguish between innocent murmurs and those indicating structural heart problems through physical examination, echocardiogram, or other cardiac tests 1.
  • Innocent murmurs are more common in children and often disappear with age, while in adults they may be related to increased cardiac output during pregnancy, exercise, anemia, or fever.
  • Regular cardiac check-ups are recommended to monitor any changes in the murmur characteristics over time.

Murmur Classification

  • Holosystolic (pansystolic) murmurs are generated when there is flow between chambers that have widely different pressures throughout systole, such as the left ventricle and either the left atrium or right ventricle 1.
  • Midsystolic (systolic ejection) murmurs, often crescendo-decrescendo in configuration, occur when blood is ejected across the aortic or pulmonic outflow tracts.
  • Early systolic murmurs are less common; they begin with the first sound and end in midsystole, often due to TR that occurs in the absence of pulmonary hypertension, but it also occurs in patients with acute MR 1.

Diagnostic Approaches

  • Echocardiography is often necessary to separate a prominent and exaggerated (grade 3) benign midsystolic murmur from one due to valvular AS 1.
  • The response to various maneuvers, such as respiration, Valsalva maneuver, exercise, positional changes, postventricular premature beat or atrial fibrillation, pharmacological interventions, and transient arterial occlusion, can help distinguish between different types of murmurs 1.

From the Research

Whistling at End of S1 S2

  • The whistling sound at the end of S1 S2 is not directly addressed in the provided studies 2, 3, 4, 5, 6.
  • However, the studies discuss various aspects of valvular heart disease, including mitral regurgitation and mitral stenosis, which can cause abnormal heart sounds.
  • Mitral regurgitation is characterized by the backflow of blood from the left ventricle to the left atrium during systole, which can produce a murmur 3, 4, 5.
  • The timing and characteristics of the murmur can vary depending on the severity and cause of the mitral regurgitation.
  • Stress echocardiography can be used to assess valve hemodynamics and identify patients with mitral valve disease who are at risk of developing symptoms 6.
  • The European Society of Cardiology's guidelines emphasize the importance of exercise stress echocardiography in patients with valvular heart disease, including those with mitral valve disease 6.
  • While the provided studies do not directly address the whistling sound at the end of S1 S2, they highlight the importance of accurate diagnosis and assessment of valvular heart disease using echocardiography and other diagnostic tools 2, 3, 4, 5, 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Valvular Heart Disease.

Primary care, 2018

Research

European Association of Echocardiography recommendations for the assessment of valvular regurgitation. Part 2: mitral and tricuspid regurgitation (native valve disease).

European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology, 2010

Research

Mitral valve interventions in heart failure.

ESC heart failure, 2018

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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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