Related Experiment Videos
Clinical implications of left atrial appendage flow patterns in nonrheumatic atrial fibrillation
1Department of Internal Medicine, National Taiwan University Hospital, Taipei, Republic of China.
Insights
Patients with chronic nonrheumatic atrial fibrillation and poor left atrial appendage (LAA) function exhibit reduced LAA blood flow. This impaired function is linked to increased LAA spontaneous echo contrast, a marker for thromboembolism risk.
Area of Science:
- Cardiology
- Echocardiography
- Vascular Physiology
Background:
- Atrial fibrillation (AF) is a common arrhythmia.
- The left atrial appendage (LAA) plays a role in thrombus formation in AF.
- Understanding LAA function is crucial for assessing thromboembolic risk.
Purpose of the Study:
- To investigate left atrial appendage (LAA) function and flow patterns in patients with chronic nonrheumatic atrial fibrillation.
- To identify differences in LAA hemodynamics between patients with varying flow patterns.
- To correlate LAA function with spontaneous echocardiographic contrast formation.
Main Methods:
- Transesophageal echocardiography (TEE) was used to assess LAA function and flow in 29 patients.
- Patients were categorized into two groups based on LAA Doppler flow signals (well-defined vs. very low).
- Key parameters analyzed included LAA ejection fraction, peak emptying velocity, and spontaneous echo contrast.
Main Results:
- Patients with very low LAA flow signals had significantly larger left atrial diameters.
- These patients also demonstrated lower LAA ejection fraction and peak emptying velocity compared to those with well-defined flow.
- A higher incidence of LAA spontaneous echocardiographic contrast was observed in the group with impaired LAA function.
Conclusions:
- A subset of patients with nonrheumatic atrial fibrillation exhibit reduced LAA blood flow and impaired LAA function.
- Impaired LAA function is associated with increased spontaneous echo contrast formation.
- These findings highlight a potential marker for increased systemic thromboembolism risk in AF patients.
Abstract:
Left atrial appendage (LAA) function and flow patterns in 29 patients with chronic nonrheumatic atrial fibrillation were studied by transesophageal echocardiography. These 29 patients (16 men and 13 women; mean age, 63.8 years; range, 38 to 77 years) were classified into two groups according to different LAA flow patterns. Seventeen patients (group 1) had well-defined LAA emptying and filling Doppler flow signals, and the other 12 patients (group 2) had very low LAA flow signals. No significant differences were found in age, sex, mean duration of atrial fibrillation, left ventricular end diastolic dimension, and left ventricular ejection fraction between the two groups. However, group 2 patients had larger left atrial diameter (42.8 +/- 4.2 mm vs 36.6 +/- 8.8 mm; p < 0.05), lower LAA ejection fraction (26.4 +/- 15.2 percent vs 42.6 +/- 14.1 percent; p < 0.05), and lower LAA peak emptying velocity (0.13 +/- 0.03 m/s vs 0.36 +/- 0.16 m/s; p < 0.001). Higher incidence of LAA spontaneous echocardiographic contrast formation in group 2 patients (8/12 vs 1/17; p < 0.001) was noted. In conclusion, a subset of patients with nonrheumatic atrial fibrillation were found to have lower LAA blood flow and poorer LAA function. These patients had higher incidence of left atrial or LAA spontaneous echo contrast formation which had been proved previously to be a marker for future systemic thromboembolism.