الفهرس 
ANATOMY OF LEFT ATRIUM, PULMONARY VEINS AND LAA
Data Management and AnalysisOnly 14 pages are availabe for public view
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Abstract
A
trial fibrillation is the most common type of cardiac arrhythmia characterized by irregular, rapid and disorganized atrial depolarizations with a discrete lack of P waves on electrocardiograms leading to an irregular ventricular rhythm (Michaud et al., 2015).
In atrial fibrillation, the atrium does not contract as strongly as it should. This can cause blood to stagnate in the heart and form clots. When the blood clots dislodge, they may move to the brain, blocking narrow brain artery flow and causing a stroke. Research suggests that over 90 percent of blood clots responsible for stroke in patients with AF originate from the left atrial appendage (LAA) (Randall et al., 2010).
Anticoaglation can be used to reduce the risk of stroke from AF. Anticoagulation is recommended for most AF patients other than those at low risk of stroke according to CHA2DS2-VASc score (Lip et al., 2015).
The aim of the study is to assess risk of thromboembolism in low risk patients with Non-Valvular AF according to CHA2DS2-VASc score using TEE and TTE and Find further reliable parameters other than detection of thrombi to exclude thromboembolic risk in this group patients.
This study included patients from Cardiology Department in Ain Shams University and Cardiology Department in El Galaa Military Medical Complex in the period from July 2016 to July 2017.
This study was conducted on 50 patients who suffer from paroxysmal or persistant Non-valvular AF documented by ECG or Holter and had low risk of thromboembolism according to CHA2DS2-VASc score (Males = 0 score, Females = 1 score).
Exclusion Criteria included:
History of AF less than 6 months, Valvular AF, Higher risk of thromboembolism according to CHA2DS2-VASc score (Males ≥1score, Females ≥2 score), other indications for oral anticoagulant intake or taking an oral anticoagulant, other forms of Arrhythmias, Left ventricular systolic Dysfunction, CCU admission in past 6 months.
All patients were subjected to:
- History intake:
History as regards: Age, Sex, hypertension, diabetes, heart disease, history of stroke, anticoagulation drugs, height, weight, type of AF, average number of AF episodes last 6 months for paroxysmal AF patients, assessment of CHA2DS2-VASc score.
- Investigations:
ECG or Holter: for documentation of AF and to exclude ischemia and other forms of arrhythmias.
TTE (trans-thoracic echocardiography):
To exclude other structural heart disease.
LA dimensions and volume
TEE (trans-esophageal echocardiography):
Assessment of left atrial appendage (Diameter of the ostium, Morphology and Velocity through LAA ostium).
Presence of thrombus or SEC.
We found that there was a statistically significant correlation between paroxysmal and persistent AF cases as regard left atrial postroanterior diameter, lateral to septal diameter, left atrial length, left atrial volume and left atrial volume index (LAVI), with higher mean values among persistent AF cases.
But there was no significant difference between paroxysmal and persistent AF cases as regard Ostial diameter, however a significant difference between paroxysmal and persistent AF was found regarding LAA velocity with lower mean value among persistent AF cases.
There was a positive correlation between frequency of AF episodes and each of left atrial postroanterior diameter, lateral to septal diameter, left atrial length, left atrial volume and left atrial volume index (LAVI), as more episodes patients had, higher values we found.
Results showed that there is a statistically significant moderate positive correlation between LAA osteal diameter and frequency of AF episodes.
Velocity has a strong negative correlation with the frequency of AF episodes, the more episodes frequency, the lower velocity we found.
There was no significant correlation between frequency of AF episodes and LAA morphology.
There is a strong negative correlation between left atrial volume index (LAVI) and left atrial appendage velocity, indicating the predictive value of the left atrial volume in regard to thromboembolic risk.
Our study suggested that identification of the indexed left atrial volume and LAA velocity with a lower risk for stroke may further guide the clinicians in the decision process. The findings of the present study suggest that left atrial volume index and LAA velocity may be taken into account when planning the anticoagulation management of patients with AF, further study of non low risk patients needed to confirm previous data.