The Echocardiological Research On The Shape And Function Of The LA And LAA In NVAF Patients

PART Ⅰ Left Atrial Appendage Amputation Using a Modified Appendage Clip:an Experimental Canine StudyObjective:To evaluate the safety,effectiveness and feasibility of a modified left atrial appendage clip（LAAC）in dogs by echocardiography.Methods:24 healthy Labrador retrievers underwent mini-invasive off-pump placement of a modified LAAC.Echocardiography was used intra-and post-operatively to assess left atrial appendage（LAA）perfusion,morphology,and overall cardiac function.Biochemical and histological studies were performed at 7,60,90 and 180 days.Results:Amputation of LAA were successfully achieved in all dogs（successful rate was 100%）without major complications such as cardiac tamponade,hemodynamic instability and without affecting cardiac function.Next we showed atrial natriuretic peptide（ANP）levels were markedly reduced at 7,60 and 90 days after LAAC placement compared with pre-operative data,respectively（P<0.05）.And LAA atrophy was found at 60,90 and 180 days after LAA clipping.Conclusions:In dogs,easy,reliable,and safe exclusion of the LAA was achieved by using the modified LAAC with favorable echocardiographic and histological results.The study may provide some supportive data for LAA amputation in clinic.PART Ⅱ Evaluation of the Morphology and Function of the LA and LAA in Patients with Atrial Fibrillation by EchocardiographyObjective:To evaluate the morphological and functional characteristics of the left atrial and left atrial appendage in patients with cardiogenic stroke in atrial fibrillation by echocardiography and two-dimensional speckle tracking.Methods:Seventy-two patients with Non-Valvular Atrial Fibrillation（NVAF）were selected and were divided into stroke group（22 cases）and non-stroke group（50 cases）according to whether they had stroke or not.The clinical data of each group were collected.Transthoracic Echocardiography（TTE）was used to measure the left atrial diameter（LAD）,index of left atrial volume（LAVI）,left ventrical ejection fraction（LVEF）,mitrial valve E peak（E）,annular mitrial valve e’ peak（e’）.Two-dimensional speckle tracing imaging（2D-STI）was performed to measure left atrial reservoir strain（LASr）.Transesophageal Echocardiography（TEE）was used to measure the emptying velocity of left atrial appendage（LAA-Ev）,the filling velocity of left atrial appendage（LAA-Fv）and the maximum of left atrial appendage orifice area（LAA-OA max）.The variation of left atrial appendage orifice area（LAA-OA variation）was calculated.Results:（1）LAVI and LAA-OA max in the stroke group was higher than that in the nonstroke group,while LASr,LAA-Ev,LAA-Fv and LAA-OA variation were lower than those in the non-stroke group.（2）The area under ROC curve of LASr is 0.664,LASr<0.163 the sensitivity and specificity for diagnosing stroke in AF patients were 0.864 and 0.540.The area under ROC curve of LAA-Ev is 0.701,LAA-Ev<36.4 cm/s the sensitivity and specificity for diagnosing stroke in AF patients were 0.773 and 0.560.The area under ROC curve of LAAOAmax is 0.736,LAA-OA max>4.50 cm2 the sensitivity and specificity for diagnosing stroke in AF patients were 0.773 and 0.620.The area under ROC curve of LAA-OAvariation is 0.885,LAA-OAvariation<0.268 the sensitivity and specificity for diagnosing stroke in AF patients were 0.909 and 0.740.（3）LAVI high risk group>low risk group,LASr high risk group<low risk group,LAA-Fv high risk group<low risk group,LAA-OA variation high risk group<middle risk group<low risk group.Conclusions:The morphology and function of the left atrium and left atrial appendage have important clinical significance for the assessment of stroke risk in AF patients.LASr,LAA-Ev and LAA-OA max,LAA-OA variation have good predictive value for cardiogenic stroke in AF patients,and can be used as an effective supplement to CHA₂DS₂-VASC score.