Aortic Stenosis Murmur Characteristics

Aortic stenosis is associated with a distinctive type of heart murmur, typically described as a systolic ejection murmur. This murmur can be best heard at the aortic area on the right side of the upper sternum, also known as the secondary aortic listening point along the left sternal border. It presents as a loud, harsh, and rasping sound, often likened to a "squirting" or "jet-like" noise.

Understanding the Cause of the Murmur

The murmur arises due to the abnormal narrowing of the aortic valve, which restricts the flow of blood from the left ventricle into the aorta. As the heart pumps blood during systole, it must forcefully eject through a significantly narrowed valve opening. This creates turbulence in blood flow, resulting in the characteristic ejection murmur.

Key Features of the Aortic Stenosis Murmur

In severe cases, the pressure gradient across the valve can exceed 90 mmHg, leading to an extremely loud murmur. Remarkably, in some patients, the murmur can be heard even before the stethoscope touches the chest—detectable from a distance of about 2 cm away from the skin surface. This intense sound is a hallmark of significant aortic stenosis.

Timing and Duration

The murmur is described as a "pan-systolic" or "crescendo-decrescendo" murmur, meaning it begins right after the first heart sound (S1), peaks in mid-systole, and gradually decreases in intensity before the second heart sound (S2). This timing reflects the dynamic changes in pressure and flow during ventricular contraction.

Clinical Significance

Recognizing this unique murmur is crucial for early diagnosis and management of aortic stenosis. The presence of a loud, late-peaking systolic murmur, especially when accompanied by symptoms such as chest pain, syncope, or shortness of breath, should prompt further evaluation with echocardiography to assess the severity of valve narrowing.