How do you differentiate a Ventricular Assist Device (VAD) murmur from a Mitral Regurgitation murmur?

From the Guidelines

To differentiate a Ventricular Assist Device (VAD) murmur from a Mitral Regurgitation murmur, focus on the quality, timing, and location of the sounds, with VAD murmurs being continuous and mechanical, and mitral regurgitation murmurs being holosystolic and high-pitched. The key characteristics of VAD murmurs include their continuous, mechanical "hum" or "whirring" sounds that persist throughout the cardiac cycle without variation between systole and diastole, loudest at the left ventricular apex or over the device itself 1. In contrast, mitral regurgitation murmurs are holosystolic, high-pitched, blowing sounds that radiate to the axilla and are best heard at the cardiac apex, intensifying during expiration and may be accompanied by an S3 gallop 1. Additionally, VAD murmurs remain constant regardless of respiratory phase or patient position, while mitral regurgitation murmurs may vary with these factors, and the presence of a palpable thrill over the VAD site further supports a device-related murmur 1. Understanding these distinctions is crucial because VAD murmurs represent normal device function, whereas mitral regurgitation indicates pathological backflow of blood from the left ventricle to the left atrium due to incomplete mitral valve closure. Some key points to consider when differentiating these murmurs include:

• The quality and timing of the sounds
• The location where the sounds are loudest
• The presence of accompanying signs such as an S3 gallop or palpable thrill
• The variation of the murmur with respiratory phase or patient position. Given the most recent evidence from 2021, the use of imaging techniques such as transthoracic echocardiography, transesophageal echocardiography, and cine magnetic resonance imaging can aid in the accurate diagnosis of mitral regurgitation and differentiation from VAD murmurs 1.

From the Research

Differentiating Murmurs

To differentiate a Ventricular Assist Device (VAD) murmur from a Mitral Regurgitation (MR) murmur, several factors must be considered:

• The characteristics of the murmur, including its timing, location, and radiation
• The patient's medical history and underlying cardiac conditions
• The use of diagnostic imaging modalities, such as echocardiography

Mitral Regurgitation Murmur

A MR murmur is typically:

• A holosystolic or late-systolic murmur best heard at the apex
• Radiating to the axilla or back
• Associated with a systolic click or a third heart sound in some cases As noted in 2, MR is a frequent Doppler echocardiographic finding in patients after acute myocardial infarction and is an independent predictor of long-term cardiovascular mortality.

VAD Murmur

A VAD murmur is typically:

• A continuous or systolic murmur best heard at the sternum or precordium
• Related to the flow of blood through the VAD
• May be associated with other sounds, such as a humming or whirring noise However, there is limited information available in the provided studies to directly differentiate a VAD murmur from a MR murmur.

Diagnostic Approach

The diagnosis of MR or VAD murmur typically involves:

• Physical examination and auscultation
• Echocardiography to assess valve function and regurgitation severity
• Other diagnostic tests, such as cardiac catheterization or cardiac MRI, may be used in some cases As discussed in 3, advanced imaging modalities, including two-dimensional and three-dimensional echocardiography, are essential for assessing degenerative MR and differentiating it from other forms of MR.

Treatment and Management

The treatment and management of MR or VAD murmur depend on the underlying cause and severity of the condition:

• MR may be treated with medications, such as ACE inhibitors, or surgery, such as valve repair or replacement
• VAD murmur is typically managed by adjusting the VAD settings or treating any underlying conditions that may be contributing to the murmur As noted in 4, patients with MR do not experience significant changes in MR severity, LV size, or functional status after 6 months of treatment with angiotensin-converting enzyme inhibition, except for those with systemic hypertension.