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Impact of electrical cardioversion for atrial fibrillation on left atrial appendage function and spontaneous echo
R A Grimm1, W J Stewart, J D Maloney
1Department of Cardiology, Cleveland Clinic Foundation, Ohio 4195-5064.
Insights
Electrical cardioversion of atrial fibrillation can impair left atrial appendage function, increasing the risk of thrombus formation and embolization. This study shows that while function returns, it
Area of Science:
- Cardiology
- Cardiac Electrophysiology
- Echocardiography
Background:
- Systemic embolization after electrical cardioversion of atrial fibrillation is a concern.
- The precise mechanisms, particularly involving the left atrial appendage, remain unclear.
Purpose of the Study:
- To evaluate left atrial appendage (LAA) function during the peri-cardioversion period.
- To elucidate the role of LAA function in thromboembolism post-cardioversion.
Main Methods:
- Transesophageal echocardiography was used in 20 patients with atrial fibrillation.
- Left atrial appendage function was assessed before and after electrical cardioversion.
- Measurements included emptying/filling velocities, Doppler patterns, area, and presence of spontaneous echo contrast or thrombus.
Main Results:
- Organized LAA function returned in 80% of patients post-cardioversion.
- Pre-cardioversion LAA emptying velocities were higher in patients without spontaneous echo contrast.
- Post-cardioversion LAA function was impaired compared to pre-cardioversion, with increased spontaneous echo contrast in 35% of patients.
Conclusions:
- Most patients regain organized LAA function post-cardioversion.
- However, LAA function is diminished compared to pre-cardioversion levels.
- Impaired LAA function and increased spontaneous echo contrast post-cardioversion may contribute to thrombus formation and subsequent embolization.
Objectives:
This study assessed the function of the left atrial appendage in the pericardioversion period to gain insights into mechanisms involved in thromboembolism after cardioversion of atrial fibrillation.
Background:
Systemic embolization associated with electrical cardioversion of atrial fibrillation is thought to originate from the left atrium or left atrial appendage, or both. However, the mechanism involved is poorly understood.
Methods:
We studied left atrial appendage function with transesophageal echocardiography in 20 patients with atrial fibrillation before and after successful electrical cardioversion. We measured left atrial appendage emptying and filling velocities by pulsed wave Doppler echocardiography, characterized Doppler emptying patterns, measured atrial appendage areas and assessed the presence or absence of spontaneous echo contrast or thrombus.
Results:
Organized left atrial appendage function returned in 16 (80%) of 20 patients immediately after cardioversion. Atrial appendage emptying velocities before cardioversion were greater in patients without (0.39 +/- 0.02 m/s) than in those with (0.25 +/- 0.12 m/s) spontaneous echo contrast (p = 0.045). Furthermore, emptying velocities before cardioversion were significantly greater than late diastolic emptying velocities after cardioversion (0.31 +/- 0.15 vs. 0.14 +/- 0.12 m/s, p = 0.0001), as well as in both the group with (0.25 +/- 0.12 vs. 0.13 +/- 0.13 m/s, p = 0.001) and the group without (0.39 +/- 0.02 vs. 0.15 +/- 0.12 m/s, p = 0.01) spontaneous echo contrast. In addition, left atrial and atrial appendage spontaneous echo contrast developed in 4 of 20 patients and increased in intensity in 3 of 20 patients in the immediate postcardioversion period.
Conclusions:
Organized left atrial appendage function returns in most patients immediately after cardioversion of atrial fibrillation. However, its function is impaired compared with that before cardioversion. Furthermore, spontaneous echo contrast increased in 7 (35%) of 20 patients after cardioversion. These observations suggest that stunned left atrial appendage function after cardioversion may predispose the chamber to thrombus formation, which may play a role in the mechanism involved in the occurrence of embolization after cardioversion.