From the Guidelines
Pulmonic regurgitation is characterized by a decrescendo diastolic murmur that is typically soft, blowing, and high-pitched, beginning immediately after the second heart sound (P2) and decreasing in intensity throughout diastole, as described in the guidelines by 1. The murmur is best heard at the left upper sternal border (2nd-3rd intercostal space) and is usually accentuated during inspiration due to increased venous return. It can be distinguished from aortic regurgitation by its location, respiratory variation, and association with right-sided heart findings rather than left ventricular effects. Some key characteristics of the murmur associated with pulmonic regurgitation include:
- A decrescendo pattern, with the murmur decreasing in intensity throughout diastole
- A high-pitched sound, although it can be low to medium pitched in cases without pulmonary hypertension, as noted in 1
- Accentuation during inspiration
- Association with right-sided heart findings, such as right ventricular dilatation and diminished systolic performance, as discussed in 1 Pulmonic regurgitation occurs when the pulmonic valve fails to close properly, allowing blood to flow backward from the pulmonary artery into the right ventricle during diastole. Common causes include pulmonary hypertension, infective endocarditis, congenital abnormalities, or prior surgical intervention, as mentioned in 1. In cases of pulmonary hypertension, the murmur may be louder and accompanied by a prominent P2. When examining for this murmur, having the patient lean forward, exhale completely, and hold their breath can sometimes make it more audible. It is essential to evaluate the severity of pulmonic regurgitation and its impact on right ventricular function, as severe regurgitation can lead to significant morbidity and mortality, including congestive heart failure and ventricular arrhythmias, as highlighted in 1.
From the Research
Characteristics of the Murmur Associated with Pulmonic Regurgitation
- The murmur associated with pulmonic regurgitation is typically a mid-frequency diastolic decrescendo murmur 2
- It begins after the pulmonic component of the second heart sound 2
- The murmur can be harsh and diastolic, indicating severe pulmonary regurgitation and a non-functioning pulmonary valve 3
- In some cases, the murmur can be accompanied by other heart sounds, such as a widely split first heart sound, a single second heart sound, and right-sided third and fourth heart sounds, indicating right-sided heart failure and a severely dilated right ventricle 3
- The murmur can also be affected by respiration, with inspiration increasing the loudness of the diastolic murmurs in some patients 4
- Pulmonic regurgitation can also be associated with a right-sided Austin Flint murmur, which is a mid-diastolic and presystolic murmur maximally heard in the outflow tract of the right ventricle 4