1. Introduction
Atrial fibrillation (AF) is characterized by rapid and disorganized
electrical activation of the atrium which leads to loss of efficient
atrial contraction.1,
2 The loss of organized atrial
contraction provokes blood stasis especially in the left atrial
appendage (LAA) which can be visualized by trans-esophageal
echocardiography (TEE) as spontaneous echo-contrast
(SEC).3,
4 The blood stasis can serve as a nidus
for thrombus formation leading to clinical stroke, a major complication
of AF.4-8 Evaluation of
hemodynamics of LAA is performed with TEE by detecting SEC of measuring
LAA flow velocity. However, TEE is an invasive procedure and
procedure-related complications such as esophageal injury can occur.
Furthermore, most patients require intravenous sedatives due to pain and
inconvenience related with insertion of the TEE probe. Magnetic
resonance imaging (MRI), a non-invasive test compared with TEE, can
measure the flow volume of
LAA.9 Velocity-encoded
(VENC) cardiac MRI enables measurement of LAA blood volume during the
cardiac cycle and has strong correlation with TEE parameters of LAA
hemodynamics.10,
11 Previous reports revealed that the
evaluation of LAA blood flow with VENC-MRI can identify blood stasis in
LA and LAA.10
The role of radiofrequency catheter ablation (RFCA) in AF patients was
largely limited to improvements in the quality of life and subjective
symptoms.12,
13 However, recent studies suggest that
the beneficial effect of RFCA extends beyond quality of
life.14-16 Although the
reduction of ischemic stroke by RFCA in AF patients has not been
demonstrated in randomized clinical trials, various observational
studies suggest that RFCA can reduce the risk of ischemic
stroke.15-18Restoration of sinus rhythm might significantly improve hemodynamics of
LAA. In the other hand, scar formation due to radiofrequency energy
delivery might have adverse influence on LAA. Impact of RFCA on LAA
hemodynamics AF patients is not fully evaluated. We aimed to measure the
flow volume of LAA before and after RFCA with VENC-MRI in AF patients.