why early diastolic murmur of aortic regurgitation is decrescendo . Why its intensity decreases ?
The early diastolic murmur of aortic regurgitation is described as a decrescendo murmur because of the way blood flows and the pressure changes within the heart during diastole (when the heart is relaxed and filling with blood). Let’s delve into the reasons behind this characteristic decrescendo pattern:
- Flow of Blood during Diastole:
- During diastole, blood flows from the aorta (where it’s already been pumped) back into the left ventricle due to aortic valve incompetence in aortic regurgitation.
- Initially, when diastole begins, there’s a rapid flow of blood from the aorta into the left ventricle.
- Rapid Flow and High Pressure Gradient:
- At the start of diastole, the pressure in the aorta is higher than the pressure in the left ventricle, leading to a rapid flow of blood from the aorta into the ventricle.
- This high-pressure gradient between the aorta and the left ventricle results in an intense murmur.
- Deceleration of Blood Flow:
- As diastole progresses, the pressure gradient decreases because blood continues to flow back into the ventricle, causing the aortic pressure to fall.
- The deceleration of blood flow and decrease in pressure gradient lead to a gradual reduction in the intensity of the murmur (decrescendo).
- Decrescendo Murmur Pattern:
- The decrescendo pattern describes the decreasing intensity of the murmur as diastole progresses, reflecting the decreasing pressure gradient and slowing blood flow from the aorta to the left ventricle.
In summary, the decrescendo pattern of the early diastolic murmur in aortic regurgitation is a result of the rapid initial flow of blood from the aorta to the left ventricle at the onset of diastole, followed by a decrease in pressure gradient and slowing of blood flow, leading to a reduction in murmur intensity.