Congenital absence of the left atrial appendage is a rare congenital cardiac anomaly which is usually an incidental finding. We present a rare case of congenital absence of the left atrial appendage in a 77-year-old female patient with atrial fibrillation, and we will discuss the role of anticoagulation in the patient with congenital absence of the left atrial appendage based on the scientific data and theoretic background.
Congenital absence of the left atrial appendage (CALAA) is an extremely rare congenital cardiac anomaly. Given the fact that it is very rare, its clinical significance and the chance of developing intracardiac thrombi are largely unknown. There are only a handful case reports noted in the medical literature, and none of them reported intracardiac thrombi. The anticoagulation therapy in patients with CALAA remains unclear.
A 77-year-old female with hypertension, hyperlipidemia, and paroxysmal atrial fibrillation (AF) presented with palpitations. She has neither prior cardiovascular procedure nor cardiac surgery. AF was diagnosed 4 years ago, and she was started on oral anticoagulation with warfarin. She was active and independent. She was very symptomatic with frequent palpitations. Dofetilide was started for rhythm control. She was successfully cardioverted in January 2017 while on dofetilide and warfarin. However, she went back to AF in March 2017. Dofetilide dose was adjusted. Then, she converted to sinus rhythm and always reported to be compliant with the medication. In May 2017, she had palpitations and was found to be in AF again. Given the fact that symptomatic AF is affecting her daily life and she failed rhythm control therapy, ablation was offered. She underwent cryoablation and pulmonary vein isolation procedure.
Computed tomography angiogram of the pulmonary veins (Figures
Computed tomography angiogram (CTA) of the pulmonary veins at 47 degrees left anterior oblique (LAO) view showing there is no left atrial appendage on the left atrium.
CTA of the pulmonary veins at anteroposterior (AP) view showing there is no left atrial appendage.
CTA of the pulmonary veins at 97 degrees steep LAO view showing there is no left atrial appendage on the heart surface.
Transesophageal echocardiogram (TEE) at aortic valve level, 19-degree angle midesophageal view shows the pulmonary vein but the absence of the left atrial appendage at the usual anatomical location marked with an asterisk (
TEE at 50 degrees angle midesophageal view showing the coumadin ridge and pulmonary vein (PV). Note that there is no left atrial appendage in the area marked with (
LAA is a small muscular extension abutting from the upper part of the left atrium. Embryologically, the LAA develops as early as the third week of embryonic life [
The major clinical significance of the LAA is not in the functionality but for its lethality. In the past, the left atrial appendage (LAA) has been considered to be a relatively insignificant portion of cardiac anatomy. It is now recognized that it is a structure with important pathological associations [
Evaluation of the LAA by cardiac imaging studies prior to intracardiac procedures is usually done to rule out intracardiac thrombi. Reduced or absent LAA inflow and outflow velocities and low LAA ejection fractions are associated with LAA thrombus formation [
Advanced sonographic techniques such as biplane and multiplane TEE have enabled physicians to visualize the LAA in most cases [
Theoretically, the risk of cerebrovascular accident (CVA) in CALAA should be lower since it removes the anatomical source of cardiac embolism [
According to the 2017 expert consensus statement on ablation of AF, the decision to discontinue anticoagulation after ablation should be based on the patient’s stroke risk profile, not on the clinical outcome of the procedure [
CALAA is a very rare anomaly, which can change anticoagulation management strategies in a patient with AF, and there is very limited data to confirm the lower risk of stroke in a patient with CALAA. Given the importance of the LAA in the clot formation and embolization causing CVA in an AF patient, whether its congenital absence decreases the risk of thrombus formation is yet to be seen.
The case report was previously presented as a poster presentation at the Miami Valves 2018 conference on February 3, 2018.
The authors declare that there is no conflict of interest regarding the publication of this paper.
The corresponding author would like to thank her colleagues for their wonderful collaborations and support.