Patterns of Doppler-measured blood flow velocity in the normal and fibrillating human left atrial appendage

Area of Science:

• Cardiology
• Echocardiography
• Vascular Physiology

Background:

• Transesophageal echocardiography (TEE) Doppler measurement of left atrial appendage (LAA) blood velocity is a proposed method for assessing LAA contractile function and thromboembolic risk.
• Understanding LAA blood flow patterns is crucial for managing patients with atrial fibrillation (AF).

Purpose of the Study:

• To examine clinical and echocardiographic determinants of LAA Doppler blood velocity patterns.
• To differentiate LAA blood velocity patterns in patients with AF, controls, and those with sinus rhythm and left ventricular hypertrophy.

Main Methods:

• Doppler measurement of LAA blood velocity via TEE.
• Analysis of clinical and echocardiographic data in 40 AF patients, 10 controls, and 5 patients with sinus rhythm and left ventricular hypertrophy.

Main Results:

• In sinus rhythm, two LAA blood velocity patterns were identified, related to passive emptying, age, and left ventricular diastolic function.
• In AF, three patterns were distinguished based on preserved LAA mechanical function during fibrillation.
• LAA contractile function influences, but does not solely determine, LAA blood flow.

Conclusions:

• LAA Doppler velocity patterns provide insights into LAA function in both sinus rhythm and AF.
• Age and left ventricular diastolic properties affect LAA blood flow in sinus rhythm.
• LAA mechanical function plays a role in determining blood flow patterns during AF.