Systolic murmur is associated with ?
**Core Concept**
A systolic murmur is a type of heart sound that occurs during the systolic phase of the cardiac cycle, which is the period of time when the heart muscle contracts and pumps blood out of the heart. Systolic murmurs are often associated with abnormal blood flow patterns, such as turbulent or regurgitant flow, which can be caused by a variety of cardiac conditions.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of systolic murmurs, which are often caused by an obstruction to blood flow or a regurgitation of blood from a higher pressure chamber into a lower pressure chamber. This can occur due to conditions such as aortic stenosis, where the aortic valve is narrowed, or mitral regurgitation, where the mitral valve is leaky. The turbulent blood flow associated with these conditions creates the characteristic sound of a systolic murmur.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because diastolic murmurs occur during the diastolic phase of the cardiac cycle, when the heart muscle is relaxing and filling with blood.
**Option B:** This option is incorrect because a pericardial rub is a different type of heart sound that occurs when the pericardium, the sac surrounding the heart, becomes inflamed or irritated.
**Option C:** This option is incorrect because a third heart sound (S3) occurs during early diastole and is often associated with increased volume or pressure in the ventricle.
**Clinical Pearl / High-Yield Fact**
A classic exam question to remember is that systolic murmurs are often associated with conditions that cause turbulent or regurgitant blood flow, such as aortic stenosis or mitral regurgitation. This can be remembered using the mnemonic "SAM" - Systolic murmur, Aortic stenosis, Mitral regurgitation.
**Correct Answer:** C.