Role of tumor necrosis factor-alpha in the pathogenesis of atrial fibrillation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Tumor necrosis factor-alpha (TNF-α) is a pleiotropic proinflammatory cytokine and contributes to many kinds of cardiovascular diseases via its receptors (TNFR1/TNFR2). We hypothesize that TNF-α plays a role in the pathogenesis of chronic atrial fibrillation (AF).</p><p><b>METHODS</b>Sixty-seven consecutive patients who were scheduled to have cardiac surgery were enrolled into the study. Thirty-one patients with rheumatic heart disease (RHD) and AF were enrolled as study group (AF group). The sinus rhythm (SR) control groups consisted of 20 patients with RHD and 16 patients with coronary artery disease (CAD). Peripheral blood sample was collected before the operation. About 5 mm(3) left atrial tissue was disserted during the operation and was separated into three parts for Western blotting, real time polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC) analysis.</p><p><b>RESULTS</b>Compared with the controls (RHD SR and CAD SR), the levels of TNF-α ((14.40 ± 5.45) pg/ml vs. (4.20 ± 3.19) pg/ml vs. (2.68 ± 2.20) pg/ml, P = 0.000) and its soluble receptor 1 (sTNFR1) ((1623.9 ± 558.6) pg/ml vs. (1222.3 ± 175.6) pg/ml vs. (1387.5 ± 362.2) pg/ml, P = 0.001) in plasma were higher in patients with AF. TNF-α level had positive correlation with the left atrial diameter (LAD) (r = 0.642, P = 0.000). Western blotting analysis showed that the protein levels of TNF-α (0.618 ± 0.236 vs. 0.234 ± 0.178 vs. 0.180 ± 0.103, P = 0.000) were higher in patients with AF. The RT-PCR analysis results demonstrated that the mRNA expression of TNF-α (0.103 ± 0.047 vs. 0.031 ± 0.027 vs. 0.023 ± 0.018, P = 0.000) increased in patients with AF. IHC analysis displayed that, comparing to the SR, the expression of TNF-α (0.125 ± 0.025 vs. 0.080 ± 0.027 vs. 0.070 ± 0.023, P = 0.000) increased in the AF group. The protein level and mRNA expression of TNF-α also had positive correlation with left atrium diameter (LAD) (r = 0.415, P = 0.000 and r = 0.499, P = 0.000).</p><p><b>CONCLUSIONS</b>The results revealed that TNF-α elevated in the plasma and left atrial tissue and had positive correlation with LAD in patients of chronic AF. TNF-α might involve in the pathogenesis of chronic AF.</p>

Left atrial size and function after radiofrequency catheter ablation for paroxysmal atrial fibrillation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the impact of radiofrequency catheter ablation on left atrial (LA) size and function in patients with paroxysmal atrial fibrillation (PAF) and whether there is any difference between segmental pulmonary vein ostial isolation (SPVI) and circumferential pulmonary vein ablation (CPVA).</p><p><b>METHODS</b>Sixty-six patients with highly symptomatic atrial fibrillation were assigned to undergo either SPVI or CPVA. Transthorax echocardiography was performed before, 1 day, 1 months and 3 months after the procedure. LA dimension, LA area, late diastolic peak velocity of mitral valve inflow (A) and peak atrial systolic mitral annulus velocity (A') were recorded.</p><p><b>RESULTS</b>Of 66 consecutive patients with symptomatic PAF, 30 patients underwent SPVI and 36 underwent CPVA. After a mean follow-up of (315 +/- 153) days, 21 patients (70%) after SPVI and 28 patients (75%) after CPVA were free of atrial tachyarrhythmia. As compared with the baseline, LA area decreased at 1-month after ablation in SPVI group and at 3-month in CPVA group. LA dimension decreased also in SPVI group, but did not in CPVA group. A velocity and A' velocity declined remarkably 1 day after CPVA, and restored 3 months later. The former went back to the level of baseline, and the latter exceeded it apparently. In SPVI group, A velocity increased at 1-month, and maintained in 3-month after ablation. A' velocity increased at 3-month after ablation. No reduction of A velocity or A' velocity was found after SPVI.</p><p><b>CONCLUSIONS</b>This study demonstrated a decrease in LA area and an improvement in LA systolic function 3 months after ablation for PAF. The LA damage by CPVA was more than that by SPVI, which was characterized by the reduction of LA function 1 day after procedure and the delayed improvement of LA size and functional parameters.</p>