What is the murmur associated with aortic stenosis?

From the Guidelines

The murmur of aortic stenosis is typically a harsh, crescendo-decrescendo systolic ejection murmur that is best heard at the right upper sternal border (second right intercostal space) with radiation to the carotid arteries. This characteristic murmur occurs because the narrowed aortic valve creates turbulent blood flow as the left ventricle ejects blood into the aorta during systole. The murmur is usually grade 3-4/6 in moderate stenosis but may paradoxically decrease in very severe stenosis as cardiac output falls. Associated findings include a delayed and diminished carotid upstroke (pulsus parvus et tardus), a sustained apical impulse, and an absent or diminished aortic component of the second heart sound (A2) 1. The murmur typically increases with maneuvers that decrease venous return (such as standing or Valsalva) and decreases with maneuvers that increase venous return (such as squatting). The severity of the murmur doesn't always correlate with the severity of stenosis, particularly in elderly patients with calcific aortic stenosis or in patients with heart failure and reduced cardiac output. Some key points to consider when evaluating a patient with aortic stenosis include:

• The presence of symptoms such as exertional shortness of breath, angina, dizziness, or syncope 1
• The degree of valve calcification, LV function and wall thickness, and the presence of other associated valve disease 1
• The use of echocardiography as the key diagnostic tool to confirm the presence of AS, assess the degree of valve calcification, and provide prognostic information 1
• The importance of considering valve area in combination with flow rate, pressure gradient, and ventricular function, as well as functional status, when making clinical decisions 1.

From the Research

Aortic Stenosis Murmur

• The murmur associated with aortic stenosis is typically a harsh, crescendo-decrescendo systolic murmur heard best at the right second intercostal space [@\5@ is not relevant to this topic].
• However, the provided studies do not directly describe the characteristics of the murmur in aortic stenosis, but rather focus on the medical treatment of the condition [@\1@, @\2@, @\3@, @\4@].

Medical Treatment

• The use of renin-angiotensin system (RAS) inhibitors and beta-blockers has been studied in the context of aortic stenosis [@\1@, @\2@, @\3@, @\4@].
• RAS inhibition has been shown to be associated with a lower risk of all-cause mortality in patients with reduced left ventricular ejection fraction (LV-EF) and preserved LV-EF [@\2@].
• Beta-blockade has been associated with a lower risk of all-cause mortality in patients with reduced LV-EF, but not in preserved LV-EF [@\2@].
• Beta-blocker therapy may improve cardiac performance by reducing cardiac volume and mass in patients with impaired LV function after aortic valve replacement for aortic regurgitation [@\3@].

Antihypertensive Therapy

• The selection of antihypertensives in patients with aortic stenosis is a topic of debate due to a lack of consensus regarding their safety [@\4@].
• Antihypertensive treatment with β-blockers has generally been avoided in patients with severe aortic stenosis due to concerns for inducing left ventricular dysfunction and hemodynamic compromise [@\1@].