High-normal thyroid function and risk of recurrence of atrial fibrillation after catheter ablation.

BACKGROUND: It has been shown that the concentration of serum free thyroxine (FT(4)) is independently associated with atrial fibrillation (AF), even in euthyroid persons. This study investigated the effect of a high-normal level of FT(4) on recurrence after catheter ablation of AF. METHODS AND RESULTS: The 244 consecutive patients with paroxysmal AF and who underwent circumferential pulmonary vein isolation (PVI) were prospectively enrolled. Exclusion criteria included prior or current thyroid dysfunction on admission, amiodarone medication for 3 months before admission. After a mean follow-up of 416+/-204 (91-856) days, the recurrence rates were 14.8%, 23.0%, 33.3%, 38.7% from the lowest FT(4) quartile to the highest FT(4) quartile, respectively (P=0.016). After adjustment for age, sex, left atrial diameter, and PVI, there was an increased risk of recurrence in the subjects with the highest FT(4) quartile compared with those with the lowest quartile (hazard ratio 3.31, 95% confidence interval 1.45-7.54, P=0.004). As a continuous variable, FT(4) was also an independent predictor of recurrence (hazard ratio 1.10, 95% confidence interval 1.02-1.18, P=0.016). CONCLUSIONS: Patients with high-normal thyroid function were at an increased risk of AF recurrence after catheter ablation.

Mechanisms of improvement of left ventricle remodeling by trans-planting two kinds of autologous bone marrow stem cells in pigs.

BACKGROUND: The necrosis of a large number of myocardial cells after acute myocardial infarction (AMI) results in a decrease of cardiac function and ventricle remodeling. Stem cell transplantation could improve cardiac function after AMI, but the involving mechanisms have not been completely understood. The present study aimed to investigate the effects of transplantation of autologous bone marrow mononuclear cells (BM-MNC) and mesenchymal stem cells (MSCs) via the coronary artery on the ventricle remodeling after AMI as well as the mechanisms of the effects of transplantation of different stem cells on ventricle remodeling. METHODS: A total of 36 male pigs were enrolled in this study, which were divided into 4 groups: control group, simple infarct model group, BM-MNC transplantation group, and MSCs transplantation group. At 90 minutes when a miniature porcine model with AMI was established, transplantation of autologous BM-MNC ((4.7 +/- 1.7) x 10(7)) and MSCs ((6.2 +/- 1.6) x 10(5)) was performed in the coronary artery via a catheter. Ultrasound, electron microscope, immunohistochemical examination and real time reverse transcriptase-polymerase chain reaction were used respectively to observe cardiac functions, counts of blood vessels of cardiac muscle, cardiac muscle nuclear factor (NF)-kappaB, myocardial cell apoptosis, and the expression of the mRNA of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in cardiac muscles. Multivariate Logistic regression was used to analyze the correlation factors of left ventricular end-diastolic diameter (EDD). RESULTS: The number of blood vessels in the infarct zone and around its border in the BM-MNC transplantation group was more than those in the infarct model group and MSCs group (P = 0.0001) and there was less myocardial cell apoptosis in the stem cell transplantation group than that in the infarct model group (all P < 0.01). The positive rate of NF-kappaB in the stem cell transplantation group was lower than that in the infarct model group (P = 0.001). The gene expression of VEGF in the infarct border zone of the BM-MNC group was higher than that in the MSCs group (P = 0.0001). The gene expression of bFGF in the infarct border zone in the MSCs transplantation group was higher than that in the infarct model group and the BM-MNC group (P = 0.0001). Left ventricular ejection fraction was inversely proportional to the apoptotic rate of myocardial cells and cardiac muscle NF-kappaB but positively correlated with the number of blood vessels and the expression of VEGF and bFGF in the infarct zone and infarct border zone. The Multivariate Logistic regression analysis on the factors influencing the left ventricular end-diastolic diameter after stem cell transplantation showed that the expression of VEGF mRNA in the cardiac muscles in the infarct zone, the number of apoptotic myocardial cells and the expression of NF-kappaB in the infarct border zone were independent factors for predicting the inhibitory effect on the dilation of left ventricular EDD after stem cell transplantation. CONCLUSIONS: Transplantation of autologous BM-MNC and MSCs in pigs can improve the condition of left ventricular remodeling and recover the cardiac functions after AMI. The improvement of cardiac functions is related to the increase of blood vessels, the increased expression of VEGF and bFGF, the reduction of myocardial cell apoptosis, and the decrease of NF-kappaB level in cardiac muscle tissues after stem cell transplantation.

Predictive value of early recurrence and delayed cure after catheter ablation for patients with chronic atrial fibrillation.

BACKGROUND: Radiofrequency catheter ablation (RFCA) for curing atrial fibrillation (AF) is often followed by early recurrence and delayed cure, so the present study investigate the predictive factors this in patients with chronic AF. METHODS AND RESULTS: Ninety-two consecutive patients (70 males; mean age, 58.7+/-6.4 years) with chronic AF who underwent RFCA for treatment of symptomatic AF were enrolled. Early recurrence of AF (ERAF) occurred in 45 patients after ablation. Not achieving AF termination could predict ERAF (odds ratio (OR) 0.95; 95% confidence interval (CI) 0.84-1.13; p=0.02) in multivariate analysis. During a follow-up of 12+/-11 (range, 5-25) months, delayed cure occurred in 35.6% (16/45) of the patients with ERAF. Left atrial size and AF termination during ablation were related to delayed cure. AF termination was the only independent predictive factor for delayed cure (OR 1.47; 95% CI 1.05-1.87; p=0.02). CONCLUSION: Not achieving AF termination is the only independent predictor of ERAF. Among patients with ERAF, those with a smaller left atrium and AF termination have a higher probability of delayed cure. AF termination can independently predict delayed cure. These results emphasize the importance of AF termination during ablation for patients with chronic AF.

[Asymptomatic recurrence of atrial tachy-arrhythmia after circumferential pulmonary vein isolation in patients with atrial fibrillation].

OBJECTIVE: To investigate the incidence, type, and predictors of asymptomatic relapse of atrial tachy-arrhythmia (ATa) after circumferential pulmonary vein isolation (CPVI) in patients with atrial fibrillation (AF). METHODS: Forty-eight consecutive patients with AF underwent CPVI and were followed up. Forty-eight hours Holter recording was performed 1, 3, and 6 months respectively after the initial CPVI procedure. Predictors of asymptomatic ATa relapse were determined by Logistic regression analysis for eight variables as follows: age, gender, AF type, existence of organic heart disease, diameter of left atria, left ventricular ejection fraction, procedure time, and heart rate variability after the procedure. RESULTS: Complete Holter data were acquired in 42 patients, 26 males and 16 females, aged: 58 +/- 14, including 25 patients with paroxysmal AF and 17 with non-paroxysmal AF. The standard deviations of R-R interval (SDNN) of the non-paroxysmal AF group was 92 ms +/- 19 ms, significantly longer than that of the paroxysmal AF group (78 ms +/- 15 ms, P = 0.011). The incidence of asymptomatic ATa recurrence rates 1, 3 and 6 months after CPVI were 8%, 12%, and 8% respectively in paroxysmal AF group and 23.5%, 29.4%, and 35.3% respectively in the non-paroxysmal AF group. The incidence of asymptomatic ATa recurrence 6 months after CPVI in the non-paroxysmal AF group was significant higher than that in the paroxysmal AF group (P < 0.05). AF was the dominant arrhythmia among the asymptomatic recurrence ATa, while atrial tachycardia constituted the major arrhythmia of the symptomatic recurrent ATa. CONCLUSION: (1) Asymptomatic ATa relapse is common among the patients undergoing CPVI. (2) The dominant type of asymptomatic recurrent arrhythmia is AF. (3) The independent predictors for asymptomatic ATa recurrence include non-paroxysmal AF, left atrial enlargement, and increase of SDNN.

Catheter ablation of atrial fibrillation in patients with hyperthyroidism.

AIMS: To study the clinical efficacy of catheter ablation for treating patients with hyperthyroidism-related atrial fibrillation (AF). MATERIALS AND METHODS: The study involved 16 patients (12 males; age, 59.8 +/- 11.3 years) with hyperthyroidism-related AF, who had all been euthyroid for more than 3 months but still suffered from highly symptomatic and antiarrhythmia drug (AAD)-refractory AF. Circumferential pulmonary vein ablation (CPVA) guided by a 3-D mapping system was carried out to encircle the ipsilateral pulmonary veins (PVs) with a procedural endpoint of continuity of the circular lesions and PV isolation. Success was defined as the absence of any atrial tachyarrhythmia (ATa) off AADs beyond the first 3 months after the procedure. RESULTS: CPVA was safely carried out in each of the 16 patients without any complications. PV isolation was achieved in all the treated PVs. After a mean follow-up of 15.8 +/- 11.8 (range, 6-55) months, 9 patients (56%) were free of ATa without any AADs beyond the first 3 months. AF relapsed in the remaining 7 patients, among whom 4 responded to AAD therapy and 3 were totally unresponsive. CONCLUSION: For patients suffering hyperthyroidism-related AF, CPVA guided by a 3-D mapping system could represent one of the therapeutic options.

Can pulmonary vein antrum be defined by electrophysiological mapping?

Atrial fibrillation (AF) is the most common sustained arrhythmia, and treatments with anti-arrhythmia drugs (AADs) have been frustrating. Limitations of AADs prompted the development of percutaneous catheter ablation. In contrast to AADs, percutaneous catheter ablation offers the possibility of a lasting cure. The successful cure of AF by percutaneous catheter ablation comes from a widespread recognize that pulmonary vein antrum (PVA) plays an important role in the genesis and maintenance of AF, and circular ablation along the PVA can eliminate majority of AF. PVA is comprised of pulmonary vein-left atrium junctions. However, during ablation procedure, definition of PVA solely depends on angiography, and it is largely experience-dependent and there is a great deal of variation involved. Our study in patients with AF found that a unique potential with double deflections could be documented along PVA, but it cannot be recorded at PV side or LA side. Thus, we propose that documentation of PVA potentials can be used as a landmark to define PVA. Unlike angiography, documentation of PVA potentials can be objectively carried out by different operators, and the variations due to experience can be avoided.

[Pulmonary vein antrum isolation guided by 3-D mapping system in 100 patients with chronic atrial fibrillation].

OBJECTIVE: To investigate the efficacy and safety of circumferential pulmonary vein (PV) linear ablation (CPVA) guided by 3-D mapping system in patients with chronic atrial fibrillation (CAF). METHODS: From August 2004 to November 2005, 100 consecutive patients with CAF were admitted to undergo CPVA guided by CARTO system and EnSite NavX system, the main procedure end point is electrical isolation of PVs. Success was defined as atrial tachyarrhythmia free without any antiarrhythmia drugs for at least 3 months. Clinical and procedural variables were collected, ANOVA analysis was employed to identify the risk factors predicting recurrence, P < 0.05 was considered significant. RESULTS: After a mean of 9.7 +/- 5.7 months follow up, 70% (70/100) of patients freed from AF. ANOVA analysis identified isthmus ablation and poor left ventricular ejection fraction as the independent factors predicting success. Complications including pericardial tamponade (3 cases, 3%), stroke (1 case, 1%), asymptomatic pulmonary vein stenosis (2 cases, 2%). CONCLUSION: CPVA guided by 3-D mapping system can be performed in CAF patients with an acceptable efficacy, but safety need to be improved.

Pulmonary vein tachycardia after pulmonary vein isolation in patients with atrial fibrillation.

BACKGROUND: Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials (PVPs). Pulmonary vein tachycardia (PVT) is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear. METHODS: From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation (SPVA) or circumferential pulmonary vein ablation (CPVA). PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length (CL) of < 300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student's t test and categorical variables were analyzed by chi-square test. RESULTS: Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs (including 790 PVs) were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% (992/1105) of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % (113/1105) of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of (155 +/- 43) ms (2 PVTs in 2 patients received SPVA, 26 PVTs in 18 patients underwent CPVA). PVT was more frequently documented in patients underwent CPVA approach [9.0% (18/200) vs 2.3% (2/85), P = 0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between patients with PVT and those without PVT (P = 0.75). CONCLUSIONS: PVT dissociated from LA activations can be documented after PV isolation, especially in patients underwent CPVA approach. However, PVT does not affect the follow-up results.

Safety and efficacy of catheter ablation of atrial fibrillation in patients with diabetes mellitus--single center experience.

BACKGROUND AND OBJECTIVE: Little is known about the outcome of catheter ablation of atrial fibrillation (AF) in patients with diabetes mellitus (DM). We investigated the safety and efficacy of catheter ablation of AF in patients with DM. MATERIALS AND METHODS: Thirty one patients with DM from a group of 263 consecutive patients undergoing a first-time catheter ablation of AF procedure were enrolled in a prospective study. The ablation protocol (guided by CARTO system) consisted in two continuous circular lesions around ipsilateral pulmonary veins. RESULTS: The following clinical characteristics differed between DM and no-DM patients: age (62.0 +/- 10.8 vs. 56.1 +/- 10.6 years, P = 0.004), longer AF history (9.6 +/- 9.3 vs. 6.7 +/- 6.3 years, P = 0.024), significantly larger left atrium size (41.1 +/- 7.8 vs. 38.3 +/- 5.8 mm, P = 0.021), hypertension (58.1 vs. 35.8%, P = 0.018) and structural heart disease (67.7 vs. 43.5%, P = 0.011). Despite a similar AF recurrence rate in DM and no-DM patients (32.3 vs. 22.4%, P = 0.240), the ablation procedure was complicated in 28 patients (11 hematomas, three cardiac tamponades and three strokes) and the incidence of complications was significantly higher in DM than in no-DM patients (29.0 vs. 8.2%, respectively, P = 0.002). Multivariate analysis showed that DM was an independent risk factor for complications occurrence (odd ratio 5.936, 95% confidence interval 2.059 to 17.112, P = 0.001). CONCLUSIONS: First catheter ablation of AF procedure in DM patients was equally efficacious than in no-DM patients. However, DM patients had a higher incidence of complications, mostly thrombotic or hemorrhagic.