What is the significance of a buzzing sound heard while auscultating blood pressure in an older adult patient with aortic valve stenosis and potential dementia?

Buzzing Sound During Blood Pressure Auscultation in Aortic Stenosis

The "buzzing sound" you're hearing is likely the transmitted systolic ejection murmur of aortic stenosis being conducted through the brachial artery, which is a normal finding when auscultating blood pressure in patients with significant AS—this does not represent a separate pathology but rather confirms the presence of turbulent flow across the stenotic valve. 1

Understanding the Acoustic Phenomenon

The characteristic murmur of aortic stenosis is a crescendo-decrescendo (diamond-shaped) systolic ejection murmur that radiates from the apex to the upper right sternal border and, importantly, to the carotid arteries and peripheral vessels including the brachial artery. 1 This radiation pattern explains why you hear this "buzzing" during blood pressure measurement:

• The murmur transmits along the arterial tree because the turbulent, high-velocity flow across the stenotic aortic valve creates vibrations that propagate through the blood column and arterial walls 2
• When you place the stethoscope over the brachial artery for blood pressure measurement, you're essentially auscultating both the Korotkoff sounds AND the transmitted cardiac murmur simultaneously 1
• This is particularly prominent in moderate to severe AS where the gradient across the valve is significant 1, 3

Clinical Significance and Severity Assessment

The presence of a clearly audible transmitted murmur during BP measurement suggests at least moderate stenosis, as mild AS typically produces softer murmurs that may not transmit as prominently. 1 Consider these severity indicators:

Signs Suggesting Severe AS:

• Pulsus parvus et tardus (slow-rising, weak carotid pulse) - present in 61% of severe AS cases 4
• Single or paradoxically split S2 (soft or absent A2 component) 1, 5
• Late-peaking systolic murmur (grade 4/6 or louder) 1
• Lower systolic blood pressure and narrow pulse pressure compared to patients without severe stenosis 4

Important Caveat:

Classical physical examination signs can be unreliable in elderly patients, and significant AS may be missed on clinical examination alone. 6, 4 The absence of classic findings does NOT exclude severe disease, particularly in older adults where arterial stiffness can mask the typical pulse characteristics. 6

Immediate Diagnostic Approach

Echocardiography is mandatory to determine actual stenosis severity and guide management, as physical examination alone is insufficient for risk stratification. 1, 3

Indications for Urgent Echocardiography:

• Any symptoms potentially attributable to AS (dyspnea, angina, syncope, or presyncope) 1
• Grade 3/6 or louder systolic murmur 2
• Single S2 on examination 1
• New or changing symptoms in a patient with known AS 2

Echocardiographic Criteria for Severe AS:

• Aortic valve area ≤1.0 cm² 3
• Peak velocity ≥4 m/sec 3
• Mean gradient ≥40 mmHg 3

Special Considerations in Older Adults with Potential Dementia

Symptom assessment is particularly challenging in elderly patients with cognitive impairment, as they may not reliably report or recognize cardiac symptoms and often reduce physical activity to avoid symptoms. 7

Key Points:

• Symptoms may be attributed incorrectly to aging or other comorbidities rather than AS 7
• Once symptoms develop, prognosis is poor with sudden death occurring in approximately one-third of patients who die from AS 7
• Postoperative delirium is the dominant predictor of subsequent dementia (OR 3.55) in elderly patients undergoing surgical aortic valve replacement 8
• Age >80 years is also a significant predictor of dementia development (OR 2.38) 8

Management Algorithm

1. Obtain urgent transthoracic echocardiography to confirm severity and assess LV function 3
2. If severe AS is confirmed and patient is symptomatic: valve replacement is the only definitive treatment (Class I indication) 3
3. Calculate surgical risk using STS-PROM score and convene Heart Team assessment for SAVR vs TAVR decision 3
4. If asymptomatic with severe AS: close surveillance with serial echocardiography (yearly for severe AS) 5
5. Avoid aggressive vasodilators if heart failure symptoms develop while awaiting intervention 3

Critical Pitfall to Avoid:

If physical examination strongly suggests severe AS but echocardiography shows only mild stenosis, the echocardiogram has likely underestimated disease severity and further evaluation (possibly with CMR or repeat echo) is warranted. 5