Categories: Cardiology

Why do Right Sided Heart Murmurs Increase with Inspiration?

A heart “murmur” is the sound of blood flowing (i.e through a valve).

RIGHT SIDED MURMURS (i.e Tricuspid regurgitation or Pulmonary stenosis) will INCREASE WITH INspiration.

WHY? When inhaling, a more negative intra-thoracic pressure is created. This increases venous return to the right ventricle. More venous return means more blood flow over the valve and an increase in the intensity of the right sided murmur.

Likewise during EXpiration, LEFT SIDED MURMURS (i.e mitral regurgitation) INCREASE. This is due to the expanded lung parenchyma collapsing and the pooled volume of blood in it being squeezed into the left side of the heart.

Exception : MVP and HOCM murmurs DO NOT increase on expiration.


  1. Chapter 267: Physical Examination of the Cardiovascular System. Patrick T. O’Gara; Joseph Loscalzo. Harrison’s Principles of Internal Medicine, 19e
  2. Chapter 14. The History, Physical Examination, and Cardiac Auscultation. Richard A. Walsh; Robert A. O’Rourke; James A. Shaver. Hurst’s The Heart, 13e
Get Medical Pearls directly to your inbox every week!
Weekly posts with high yield medical knowledge, directly to your mailbox!
Dr. C Humphreys

Internal Medicine

Published by
Dr. C Humphreys

Recent Posts

Nocturia and OSA: Mechanism

Nocturia is a common symptom associated with obstructive sleep apnea. [1] Img Cred: Am J…

10 months ago

ASD vs. VSD Murmur Difference

ASD (Atrial Septal Defect) Wide, Fixed split S2 (in contrast to the normal variation in…

10 months ago

Mechanism of a Mixed Apnea

Mixed apneas are characterized by absent respiratory effort and airflow in the first section of…

2 years ago

How Does Hypothyroidism Cause Hypoventilation?

Although rare, the differential diagnosis of hypoventilation and hypercapnia respiratory failure includes hypothyroidism. It is…

2 years ago

Why is Pro-BNP/ BNP lower in Obesity?

B-type natriuretic peptide (BNP) is a hormone created in response to cardiac wall stretch due…

2 years ago

What is Peribronchovascular Distribution on CT imaging?

A common finding described on computed tomography (CT) imaging. A disease with a peribronchovascular distribution…

3 years ago

This website uses cookies.