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Calcium-Induced Autonomic Denervation in Patients With Post-Operative Atrial Fibrillation.
Wang, H, Zhang, Y, Xin, F, Jiang, H, Tao, D, Jin, Y, He, Y, Wang, Q, Po, SS
Journal of the American College of Cardiology. 2021;(1):57-67
Abstract
BACKGROUND Post-operative atrial fibrillation (POAF) is associated with worse long-term cardiovascular outcomes. OBJECTIVES This study hypothesized that injecting calcium chloride (CaCl2) into the major atrial ganglionated plexi (GPs) during isolated coronary artery bypass grafting (CABG) can reduce the incidence of POAF by calcium-induced autonomic neurotoxicity. METHODS This proof-of-concept study randomized 200 patients undergoing isolated, off-pump CABG to CaCl2 (n = 100) or sodium chloride (sham, n = 100) injection. Two milliliters of CaCl2 (5%) or sodium chloride (0.9%) was injected into the 4 major atrial GPs during CABG. All patients received 7-day continuous telemetry and Holter monitoring. The primary outcome was incidence of POAF (≥30 s) in 7 days. Secondary outcomes included length of hospitalization, POAF burden, average ventricular rate during AF, plasma level of inflammatory markers, and actionable antiarrhythmic therapy to treat POAF. RESULTS The POAF incidence was reduced from 36% to 15% (hazard ratio: 0.366; 95% confidence interval: 0.211 to 0.635; p = 0.001). Length of hospitalization did not differ between the 2 groups. POAF burden (first 7 post-operative days), the use of amiodarone or esmolol, and the incidence of atrial couplets and nonsustained atrial tachyarrhythmias were significantly reduced in the CaCl2 group. Heart rate variability data showed a decrease in both high-frequency and low-frequency power in the CaCl2 group with a preserved low-frequency/high-frequency ratio, suggesting that the sympathetic/parasympathetic balance was not perturbed by CaCl2 injection. CONCLUSIONS Injection of CaCl2 into the 4 major atrial GPs reduced the POAF hazard by 63%. Inhibition of GP function by Ca-mediated neurotoxicity may underlie the therapeutic effect. (Calcium Autonomic Denervation Prevents Postoperative Atrial Fibrillation; ChiCTR1800019276).
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Blood lipid levels and recurrence of atrial fibrillation after radiofrequency catheter ablation: a prospective study.
Shang, Y, Chen, N, Wang, Q, Zhuo, C, Zhao, J, Lv, N, Huang, Y
Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing. 2020;(2):221-231
Abstract
PURPOSE The relation between dyslipidemia and atrial fibrillation (AF) development remains controversial. We conducted a prospective study to investigate the association of lipids with the risk of recurrence of AF after radiofrequency catheter ablation (RFCA). METHODS This study enrolled 287 consecutive patients who underwent initial circumferential pulmonary vein ablation (CPVA). Fasting levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) were measured at baseline before ablation. Patients were classified according to lipid quartiles. AF recurrence was confirmed by 48-h electrocardiograms at follow-up visits. RESULTS A total of 71 patients (24.7%) experienced AF recurrence during 3 to 12 months after ablation. By univariate Cox regression survival analysis, TC (HR, 0.63; 95%CI, 0.48-0.82), LDL-C (HR, 0.61; 95%CI, 0.44-0.84), non-paroxysmal AF type (HR, 2.56; 95%CI, 1.52-4.21), and left atrial diameter (HR, 2.18; 95%CI, 1.46-3.24) were significantly associated with AF recurrence. By multivariate Cox regression survival analysis, lower quartiles of TC (HR, 3.66; 95%CI, 1.56-8.56) and LDL-C (HR, 2.28; 95%CI 1.09-4.77) were associated with higher risk of AF recurrence compared with the highest quartiles. After adjustment by sex, lower TC (HR, 11.70; 95%CI, 2.79-49.13) and LDL-C (HR, 11.00; 95%CI, 2.77-43.72) levels were associated with the recurrence of AF in women, but not in men. HDL-C and TG levels showed no association with AF recurrence in both genders. CONCLUSIONS TC and LDL-C levels were negatively correlated with AF recurrence after RFCA in women. HDL-C and TG were not independently associated with AF recurrence in both genders.
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Cellular and molecular mechanisms of atrial arrhythmogenesis in patients with paroxysmal atrial fibrillation.
Voigt, N, Heijman, J, Wang, Q, Chiang, DY, Li, N, Karck, M, Wehrens, XHT, Nattel, S, Dobrev, D
Circulation. 2014;(2):145-156
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Abstract
BACKGROUND Electrical, structural, and Ca2+ -handling remodeling contribute to the perpetuation/progression of atrial fibrillation (AF). Recent evidence has suggested a role for spontaneous sarcoplasmic reticulum Ca2+ -release events in long-standing persistent AF, but the occurrence and mechanisms of sarcoplasmic reticulum Ca2+ -release events in paroxysmal AF (pAF) are unknown. METHOD AND RESULTS Right-atrial appendages from control sinus rhythm patients or patients with pAF (last episode a median of 10-20 days preoperatively) were analyzed with simultaneous measurements of [Ca2+]i (fluo-3-acetoxymethyl ester) and membrane currents/action potentials (patch-clamp) in isolated atrial cardiomyocytes, and Western blot. Action potential duration, L-type Ca2+ current, and Na+ /Ca2+ -exchange current were unaltered in pAF, indicating the absence of AF-induced electrical remodeling. In contrast, there were increases in SR Ca2+ leak and incidence of delayed after-depolarizations in pAF. Ca2+ -transient amplitude and sarcoplasmic reticulum Ca2+ load (caffeine-induced Ca2+ -transient amplitude, integrated Na+/Ca2+ -exchange current) were larger in pAF. Ca2+ -transient decay was faster in pAF, but the decay of caffeine-induced Ca2+ transients was unaltered, suggesting increased SERCA2a function. In agreement, phosphorylation (inactivation) of the SERCA2a-inhibitor protein phospholamban was increased in pAF. Ryanodine receptor fractional phosphorylation was unaltered in pAF, whereas ryanodine receptor expression and single-channel open probability were increased. A novel computational model of the human atrial cardiomyocyte indicated that both ryanodine receptor dysregulation and enhanced SERCA2a activity promote increased sarcoplasmic reticulum Ca2+ leak and sarcoplasmic reticulum Ca2+ -release events, causing delayed after-depolarizations/triggered activity in pAF. CONCLUSIONS Increased diastolic sarcoplasmic reticulum Ca2+ leak and related delayed after-depolarizations/triggered activity promote cellular arrhythmogenesis in pAF patients. Biochemical, functional, and modeling studies point to a combination of increased sarcoplasmic reticulum Ca2+ load related to phospholamban hyperphosphorylation and ryanodine receptor dysregulation as underlying mechanisms.
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Effect of verapamil on prevention of atrial fibrillation in patients implanted with an implantable atrial defibrillator.
Tse, HF, Wang, Q, Yu, CM, Ayers, GM, Lau, CP
Clinical cardiology. 2001;(7):503-5
Abstract
BACKGROUND The role of verapamil in the prevention of atrial fibrillation (AF) in patients with recurrent AF is unknown. HYPOTHESIS The aim of this study was to evaluate the effect of verapamil on the prevention of AF in patients implanted with an implantable atrial defibrillator (IAD). METHODS The effects of verapamil (240 mg/day) on the total duration of AF, number of AF recurrences, and number of cardioversions were prospectively evaluated in a randomized, crossover fashion over an 8-week period in 11 patients (9 men, 2 women; mean age: 60 +/- 6 years) implanted with an IAD. RESULTS Implantable atrial defibrillators successfully converted 13 of 14 (93%) spontaneous episodes of AF. There was no significant difference in the efficacy of cardioversion (86 vs. 100%, p = 0.8), the total duration of AF (173 +/- 198 vs. 270 +/- 241 h, p = 0.5), the number of AF episodes (8.5 +/- 9.0 vs. 9.3 +/- 10.2, p = 0.3), and the number of cardioversions (1.7 +/- 2.4 vs. 1.8 +/- 2.1 p = 0.7) with or without treatment with verapamil. CONCLUSIONS The results of the present study suggest that treatment with verapamil has no significant effect on the prevention of AF in patients treated with an LAD.