Gene Expression of the Natriuretic Peptide System in Atrial Tissue of Patients with Paroxysmal and Persistent Atrial Fibrillation

INTRODUCTION: Circulating cardiac natriuretic peptides play an important role in maintaining volume homeostasis, especially during conditions affecting hemodynamics. During atrial fibrillation (AF), levels of plasma atrial natriuretic peptide (ANP) becomes elevated. The aim of this study was to gather information about gene expression of the natriuretic peptide system on the atrial level in patients with AF. METHODS AND RESULTS: Right atrial appendages of 36 patients with either paroxysmal or persistent AF were compared with 36 case matched controls in sinus rhythm for mRNA expression of pro- atrial natriuretic peptide (pro-ANP), pro-brain natriuretic peptide (pro-BNP), and their natriuretic peptide receptor type-A (NPR-A). We investigated patients without (n = 36) and with (n = 36) valvular disease. Persistent AF was associated with higher mRNA expression of pro-BNP (+66%, P = 0.04, in patients without valvular disease, and +69%, P < 0.01, in patients with valvular disease) and lower mRNA expression of NPR-A (-58%, P = 0.02, in patients without valvular disease, and -62 %, P < 0.01, in patients with valvular disease). The mRNA content of pro-ANP was only increased in patients with valvular disease (+12%, P = 0.03). No changes were observed in patients with paroxysmal AF. CONCLUSION: This study demonstrates that persistent, but not paroxysmal, AF induces alterations in gene expression of pro-BNP and NPR-A on the atrial level. Although AF generally is associated with an increase of plasma ANP level, a change in mRNA content of pro-ANP is only observed in the presence of concomitant valvular disease and is of minor magnitude.     

Atrial Natriuretic Peptide during Exercise in Patients with Coronary Heart Disease before and after Single Dose Atenolol and Acebutolol

Plasma atrial natriuretic peptide (ANP) was measured during dynamic exercise in 10 patients with coronary heart disease before and after single dose atenolol 50 mg and acebutolol 200 mg, respectively. Systolic blood pressure, heart rate and the rate-pressure product increased during exercise before and after β-blockade, but levels were lower after β-blockade. Plasma ANP levels at rest were unchanged after atenolol, but rose after acebutolol (p<0.01). During exercise plasma ANP increased significantly both before and after β-blockade, but plasma ANP levels were higher after acebutolol at all workloads (p<0.05), whereas plasma ANP levels after atenolol were higher at 125 W exclusively (p<0.05). The augmented ANP levels during exercise after β-blockade probably reflect catecholamine-stimulated ANP release, whereas the elevated plasma ANP levels after acebutolol at rest might be a β-adrenoceptor-mediated ANP release due to the intrinsic sympathomimetic effect of acebutolol.     

Catheter Ablation of Atrial Fibrillation in Patients With Valvular Heart Disease: Long‐Term Follow‐Up Results

AF Ablation in Patients With Valvular Heart Disease . Background: The purpose of this study is to evaluate the efficacy of atrial fibrillation (AF) ablation in patients with moderate valvular heart disease (VHD). Methods: In total, 534 consecutive patients who underwent AF ablation were enrolled. Patients with a history of valve surgery or other structural heart disease were excluded. Patients with clinically moderate VHD (group‐1, n = 45) were compared with those without VHD (control group‐2, n = 436). Ipsilateral pulmonary vein antrum isolation (PVAI) was performed with a double Lasso technique in all the patients. Left atrial (LA) linear ablation was undertaken in persistent AF patients, if AF was inducible after PVAI. Results: Patients in group‐1 were significantly older and had a larger LA. PVAI was successfully achieved in all the patients. Patients in group‐1 received LA linear ablation more frequently during the index procedure. After a median of 26 months from the index procedure, the freedom from AF was significantly lower in group‐1 than group‐2 off antiarrhythmic drugs (AADs) (47% vs 69%, P = 0.002). Although there were more number of total procedures in group‐1 than group‐2, the freedom from AF was lower at median 24 months after the last procedure (78% vs 87%, P = 0.038). There was no significant difference in the freedom from AF on AADs (91% vs 95%, P = 0.356) or complication rate between the 2 groups. Atrial tachycardia following the index procedure was observed more frequently in group‐1 (P = 0.001). Conclusion: The patients with VHD undergoing AF ablation are less likely to remain in sinus rhythm at long term without AADs than those without VHD. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1193‐1198, November 2010)     

老年肺心病心衰伴快速房颤的临床疗效观察

目的:比较老年肺心病中重度心功能衰竭伴快速房颤的患者静脉注射地尔硫卓及西地兰控制心室率的临床疗效和安全性.方法:采用随机单盲方法,将60例老年肺心病合并中重度心功能衰竭伴快速房颤患者分为2组,分别给予地尔硫卓和西地兰静脉注射,观察控制心室率的有效率及临床症状和体征的变化.结果:地尔硫草组控制心室率有效率为93.6%,西...     

Electrophysiological Heterogeneity of Atrial Fibrillation and Local Effect of Propafenone in the Human Right Atrium: Analysis Based on Symbolic Dynamics

A recently developed algorithm that is based on symbolic dynamics and computation of the normalized algorithmic complexity (C) was applied to basket-catheter mapping of the atrial fibrillation (AF). The aim of our study was to analyze the spatial distribution of the C during AF and effects of propafenone on this distribution. During right atrial mapping in 25 patients with AF 31 intra-atrial and 1 surface bipolar channels were acquired. The anatomical location of the intra-atrial electrodes was defined fluoroscopically. C was calculated for a moving window (size: 2000 points; step 500 points). Generated C was analyzed within 10 minutes before and after administration of propafenone. The inter-regional C distribution was analyzed using the Friedman-test (intra-individually) and Kruskall-Wallis-H-test (inter- individually). A value of p=0.05 was set for an error probability. Inter-regional C differences were found in all patients (p<0.001). The right atrium could be divided in high- and low complexity areas according to individual patterns. A significant C increase in cranio-caudal direction (with the exception of septum) was confirmed inter-individually (p<0.01). The administration of propafenone enlarged the areas of low complexity.Conclusions: This new method utilizing the combination of symbolic dynamics and adaptive power estimation can provide complex evaluation of the dynamics of AF in man. High-density mapping will be required for further evaluation of results.     

Focal initiation of sustained and nonsustained ventricular tachycardia in a canine model of ischemic cardiomyopathy

Focal Initiation of Ventricular Tachycardia in Ischemic HF. Introduction: To define the role of focal and reentrant mechanisms underlying nonsustained (NSVT) and sustained ventricular tachycardia (SuVT) induced by programmed stimulation, 3‐dimensional cardiac mapping was performed in 8 dogs with heart failure (HF) created by multiple intracoronary microsphere embolizations. Methods and Results: Continuous recording from 232 intramural sites throughout the left and right ventricles and the interventricular septum was performed during programmed stimulation in the absence and presence of isoproterenol (Iso, 0.1 μg/kg/min). Sinus beats and the last extrastimuli preceding induced VT conducted with total activation times (TA) of 51 ± 10 and 111 ± 8 milliseconds, respectively, that did not change during Iso infusion (47 ± 4 and 109 ± 5 milliseconds, P = NS). NSVT was induced in 75% of HF dogs; SuVT was induced in 38%. In all cases, initiation and maintenance of SuVT and NSVT arose by a focal mechanism. Compared to NSVT, SuVT had a shorter coupling interval (CI; 150 ± 7 vs 186 ± 16, P < 0.05) and a predilection for certain critical subendocardial initiation sites (that were initiation sites for only 29% of NSVT beats). After 21–30 beats, acceleration of SuVT by a focal mechanism to a CI less than 120 milliseconds led to functional conduction delay (TA increasing from 111 ± 3 to 137 ± 3 milliseconds, P < 0.0001), intramural reentry, and transition to ventricular fibrillation. Conclusions: Thus, initiation of SuVT in a model of ischemic HF is due to a focal mechanism. However, subsequent acceleration of this focal mechanism can ultimately lead to functional conduction delay and development of intramural reentry. (J Cardiovasc Electrophysiol, Vol. 23, pp. 543‐552, May 2012)     

Factors Associated with the Development of Atrial Fibrillation in COPD Patients: The Role of P‐Wave Dispersion

Background: Supraventricular tachyarrhythmia is a common problem in chronic obstructive pulmonary disease (COPD) patients. The purpose of this study is to analyze the factors associated with paroxysmal atrial fibrillation (AF) in COPD patients. Methods: Forty COPD patients (38 male, 2 female, mean age 60 ± 9 years) and 33 healthy controls (29 male, 4 female, mean age: 58 ± 10 years) were included in this study. Echocardiography, 24‐hour ambulatory and 12‐lead ECG, pulmonary function tests, arterial blood gases, and serum electrolytes were measured. On ECG, maximum (P_max) and minimum (P_min) duration of P wave and its difference, P‐wave dispersion (PWd), were measured. Results: On echocardiography, diastolic dysfunction was found in 14 of the 40 (35%) COPD patients. Heart rate variability analysis revealed that COPD patients had decreased SDANN, SDNN, SDNNIDX in time‐domain, and decreased LF in frequency domain parameters. Fourteen of the 40 COPD patients (35%) had AF. Patients with AF were older (57 ± 10 vs 64 ± 5 years, P = 0.03) and had lower SDANN, SDNN, and LF/HF ratio as compared to patients without AF in univariate analysis. All P‐wave intervals (P_max P_min and PWd) were increased in COPD patients compared to controls. P‐wave dispersion was significantly increased in COPD patients with AF, as compared to patients without AF (57 ± 11 vs 44 ± 7 ms, P = 0.001). In logistic regression analysis PWd was found to be the only factor associated with the development of AF (P = 0.04). Conclusions: The presence of AF was significantly related to the prolongation of PWd, but not with pulmonary function, arterial blood gasses, and left and right atrial function. A.N.E. 2002;7(3):222–227     

不同剂量辛伐他汀对慢性缺血性心脏病合并阵发性心房纤颤C反应蛋白及心电图的影响研究

目的 观察不同剂量辛伐他汀对缺血性心脏病合并阵发性房颤病人窦性心律的维持及C反应蛋白、P波离散度、P波最长时限的影响.方法 选取缺血性心脏病合并阵发性房颤病人76例,随机分为空白对照组、辛伐他汀10mg/d组、辛伐他汀20mg/d组和辛伐他汀30mg/d组;观察24周内心房纤颤复发的病例数及次数、高敏C反应蛋白、P波离散度、P波最长时限、LDL-C、HDL-C等在治疗前后的变化.结果 与空白对照组比较,不同剂量辛伐他汀组的阵发性房颤窦性维持率均增加,且随着剂量的递增而递增;与治疗前比较,不同剂量的辛伐他汀组治疗后的高敏C反应蛋白、P波离散度、P波最长时限、LDL-C水平均降低,HDL-C水平升高;治疗后的高敏C反应蛋白的降低与给予的辛伐他汀的剂量呈负相关.结论 辛伐他汀在减少房颤的发生率及增加窦性心律的维持率的同时,也降低高敏C反应蛋白、P波离散度、P波最长时限、LDL-C水平,升高HDL-C水平,且随着辛伐他汀剂量的递增,高敏C反应蛋白也相应递减.