To evaluate the volume and function of left atrium and left atrial appendage in patients with atrial fibrillation by three-dimensional transesophageal echocardiography and transthoracic echocardiography.
 Methods: A total of 112 patients with atrial fibrillation were divided into two groups: a paroxysmal atrial fibrillation (ParAF) group (n=80) and a persistent atrial fibrillation (PerAF) group (n=32). Control group was people without atrial fibrillation (n=40). Clinical data of the participants were collected. Left atrial dimension (LAD), left atrial volume (LAV), left ventricular end-diastolic volume (LVEDV) and left ventricular end-systolic volume (LVESV) were measured by transthoracic echocardiography, while left atrial appendage peak emptying flow velocity (LAAeV), left atrial appendage peak filling flow velocity (LAAfV), left atrial appendage maximum volume (LAAVmax) and left atrial appendage minimum volume (LAAVmin) were measured by three-dimensional transesophageal echocardiography. Left atrial volume index (LAVI), left ventricular ejection fraction (LVEF) and left atrial appendage ejection fraction (LAAEF) were calculated. 
 Results: Compared with the control group, LAAEF, LAAeV and LAAfV in the ParAF group were decreased obviously, while LAD, LAV, LAVI, LAAVmax and LAAVmin in the ParAF group were increased obviously (P<0.05). Compared with the ParAF group, LAAEF, LAAeV and LAAfV in the PerAF group were also decreased obviously, and LAD, LAV, LAVI, LAAVmax and LAAVmin in the ParAF group were also increased obviously (P<0.05). There was no statistically significant difference in LVEDV, LVESV, LVEF between the ParAF group and the PerAF group (P<0.05).
 Conclusion: Left atrium and left atrial appendage were enlarged and the function of left atrial appendage was declined in patients with AF, and the changes were more obvious in patients with PerAF compared with patients with ParAF by three-dimensional transesophageal echocardiography and transthoracic echocardiography.
Atrial Appendage ; physiopathology ; Atrial Fibrillation ; physiopathology ; Echocardiography, Transesophageal ; Heart Atria ; physiopathology ; Humans

Atrial Fibrillation ; physiopathology ; surgery ; Catheter Ablation ; methods ; Humans ; Treatment Outcome

Acupuncture Therapy ; Aged ; Atrial Fibrillation ; physiopathology ; therapy ; Humans ; Male

This paper applied the Shannon Entropy based on the cross correlation to analyze the epicardial signals from anterior wall of the canine atria. The result demonstrated that during sinus rhythm, the stability level of the correlation among signals from anterior right atria is much higher than the signals from anterior left atria. All the signals from the anterior wall descended when the rhythm changed from sinus rhythm to atrial fibrillation(AF). However, there were some regions still having a stable correlation during AF. The results will be helpful to enhance understanding of the correlation characteristic of AF.
Animals ; Atrial Fibrillation ; physiopathology ; Dogs ; Entropy ; Heart Atria ; physiopathology ; Pericardium ; physiopathology

Angiotensin Receptor Antagonists ; Atrial Fibrillation ; physiopathology ; Heart Atria ; cytology ; physiopathology ; Humans ; Membrane Potentials ; Receptors, Angiotensin ; agonists

This paper aims to find a new method of detecting atrial fibrillation (AF) with fast responding speed and high detecting precision by R-R intervals. Probability density function (PDF) of distance between two points in the reconstructed phase space of R-R intervals of normal sinus rhythm (NSR) and AF is studied. It is found that the distribution of PDF between NSR and AF R-R intervals is significantly different; and based on this finding, a characteristic parameter k is defined. k is used for defection among 400 NSR and 400 AF R-R intervals. The results demonstrate that the new algorithm has fast responding speed and high detecting precision (average sensitivity 97.0%, average specificity 95.2%).
Algorithms ; Atrial Fibrillation ; diagnosis ; physiopathology ; Diagnosis, Differential ; Electrocardiography ; Humans ; Signal Processing, Computer-Assisted ; Sinoatrial Node ; physiopathology

OBJECTIVETo investigate the effects of atrial excitable period (EP) on the stability of atrial fibrillation (AF) in goats.

METHODSTen female goats were instrumented with epicardial electrodes patches on the left atrium (LA) free wall. AF was induced and maintained by a home-made stimulator with frequency of 50 Hz at a 1-second duration and a 2-seconds interval. The stimulator was disconnected regularly. AF-induced duration, average AF cycle length (AFCL), and atrial effective refractory period during AF (ERP(AF)) were measured; EP was calculated by AFCL-ERP(AF).

RESULTSEight goats were studied. Persistent AF (> 24 h) could be induced in all the 8 goats within 6-16 days. When the induced AF lasted for 3-10 min or 24 h, the AFCL was 98.3 ms +/- 11.0 ms and 84.9 ms +/- 5.2 ms (P < 0.05), respectively, ERP(AF) was 90.5 ms +/- 13.2 ms and 63.0 ms +/- 4.8 ms (P < 0.05), respectively, and EP was 7.8 ms +/- 2.4 ms and 21.9 ms +/- 3.5 ms (P < 0.05), respectively.

CONCLUSIONThe decrease in ERP(AF) is more significant than the shortening in AFCL, resulting in the gradually widening of EP which may contribute to the perpetuation of AF.

Animals ; Atrial Fibrillation ; physiopathology ; Disease Models, Animal ; Electrocardiography ; Female ; Goats ; Heart Atria ; physiopathology

This study was aimed to evaluate the relationship between the changes of plasma intermedin (IMD) and atrial fibrosis in hypertensive patients with atrial fibrillation. During the period from 2010 to 2011, appropriate 150 subjects of out-patients (female 50%, male 50%) were selected in West China Hospital, Sichuan University, and were divided into three groups: the hypertension-only group, the hypertension combined with paroxysmal atrial fibrillation group and the hypertension combined with persistent atrial fibrillation group. Firstly, we collected the Physical examination results and medical history records of the patients. We then performed ultrasound cardiogram and blood biochemical tests on the patients. We also detected the plasma IMD and transforming growth factor β1 (TGF-β1) using ELISA. The results showed that compared with the hypertensive group, the plasma level of IMD, TGF-β1 and left atrium director (LAD) in the hypertensive combined with atrial fibrillation group were higher significantly. Compared with the paroxymal atrial fibrillation group, the levels of IMD, TGF-β1 and LAD were higher significantly in persistent atrial fibrillation group. Analysis of correlation and partial correlation showed that IMD was positively correlated with TGF-p1 (r=0.51, P<0. 001), IMD was positively correlated with LAD(r=0.59, P< 0.001), and TGF-β1 was positively correlated with LAD (r = 0.57, P < 0.001). The results suggest that IMD might suppress the pathophysiological process of atrial fibrillation.
Atrial Fibrillation ; physiopathology ; Female ; Humans ; Hypertension ; physiopathology ; Male ; Peptide Hormones ; blood ; Transforming Growth Factor beta1 ; blood

Arrhythmias, Cardiac ; complications ; genetics ; physiopathology ; Atrial Fibrillation ; complications ; genetics ; physiopathology ; Electrophysiology ; Humans

OBJECTIVETo identify predictors of left atrial appendage stunning after the use of electrical cardioversion to restore sinus rhythm in patients with non-valvular atrial fibrillation.

METHODSA total of 68 consecutive patients (45 men, 23 women, 60.5 +/- 8.7 years of age) with non-valvular atrial fibrillation undergoing electrical cardioversion were enlisted in this study. Clinical and echocardiographic variables were analyzed by univariate regression and multivariate logistic regression to investigate the relationship between occurrences of left atrial appendage stunning and these factors.

RESULTSUnivariate analysis revealed that, in comparing patients without and with left atrial appendage stunning, there were significant differences in the duration of atrial fibrillation > 8 weeks (32.3% vs 75.5%, P < 0.001), left atrial diameter > 50 mm (29.0% vs 54.1%, P < 0.05), left atrial emptying fraction (31.5% +/- 7.8% vs 27.1% +/- 8.5%, P < 0.05), left ventricular ejection fraction < 50% (38.7% vs 67.6%, P < 0.05), maximum electrical energy (96.8 J +/- 65.8 J vs 156.8 J +/- 100.8 J, P < 0.01), cumulative electrical energy 146.8 J +/- 142.6 J vs 290.5 J +/- 242.1 J, P < 0.01) and number of electrical cardioversion shocks (1.7 +/- 0.9 vs 2.43 +/- 1.20, P < 0.05). However, backward stepwise multivariate logistic regression analysis identified as significant and independent predictors of left atrial appendage stunning only duration of atrial fibrillation > 8 weeks (OR = 7.249, 95% CI = 1.998 - 26.304, P < 0.01), left atrial diameter > 50 mm (OR = 3.896, 95% CI = 1.105 - 13.734, P < 0.05), left ventricular ejection fraction < 50% (OR = 4.465, 95% CI = 1.51713.140, P < 0.01) and cumulative energy of electrical cardioversion (OR = 1.004, 95% CI = 1.000 - 1.008, P < 0.05).

CONCLUSIONSDuration of atrial fibrillation > 8 weeks, left atrial diameter > 50 mm, left ventricular ejection fraction < 50%, and cumulative energy of electrical cardioversion are independent predictors of left atrial appendage stunning. Anticoagulation treatment should be individualized for patients undergoing electrical cardioversion to reduce the risk of both cardioversion-related thromboembolic events and hemorrhagic complications caused by warfarin treatment.

Aged ; Aged, 80 and over ; Atrial Appendage ; physiopathology ; Atrial Fibrillation ; physiopathology ; therapy ; Electric Countershock ; adverse effects ; Female ; Humans ; Male ; Middle Aged