fumarates and Atrial-Fibrillation

We researched the necessity of quinidine fumarate or acebutolol prophylaxis in patients in whom atrial fibrillation occurred in the postdischarge period and returned to sinus rhythm after coronary artery surgery.. Prospective review.. Since 1992, 60 patients were chosen in whom atrial fibrillation occurred in early postoperative period. There were no significant differences between them and they were separated into 3 groups. In group I (20 patients) we did not give any drug, in group II (20 patients) quinidine fumarate was given and in group III (20 patients) acebutolol was given and patients were controlled for 90 days.. Atrial fibrillation occurred in one patient in group I, (5%), two in group II (10%) and two in group III (10%), (p < 0.05). Different from the other groups, atrial fibrillation was asymptomatic with low ventricular response in group III.. There were no significant differences among three groups statistically, so we suggested that long-term prevention of atrial fibrillation with quinidine fumarate or acebutolol was not necessary after coronary artery surgery.

Topics: Acebutolol; Adult; Aged; Anti-Arrhythmia Agents; Atrial Fibrillation; Coronary Vessels; Female; Fumarates; Humans; Male; Middle Aged; Postoperative Complications; Quinidine; Time Factors

Aliskiren, a direct renin inhibitor is expected to achieve sufficient suppression of renin-angiotensin system. We evaluated the effect of aliskiren on the electrical and structural remodeling in a canine atrial fibrillation (AF) model. Twenty-eight dogs were divided into three groups: (1) pacing control group (n = 12), with continuous atrial rapid pacing for 3 or 6 weeks, (2) pacing + aliskiren group (n = 12), with oral aliskiren (30 mg/kg/day), and (3) sham group (n = 4), no pacing nor drug administration. Electrophysiological properties and AF inducibility were evaluated every week. After the protocol, the left atrial tissue was sampled for the further histological and mRNA analysis. The electrical remodeling, AF inducibility, the left atrial enlargement and interstitial fibrosis were observed in pacing control group and were more prominent in the 6-week protocol (vs. 3 week, p < 0.05). The mRNA expressions of matricellular proteins exhibited upregulation in 3-week pacing control, but these upregulations became insignificant in 6 weeks. In contrast, collagen type 3 exhibited significant upregulation in 6 week but not in 3-week protocol. These changes were suppressed in the pacing + aliskiren group. Aliskiren suppressed the atrial remodeling in a canine AF model. This effect was accompanied by the suppression of tissue fibrosis.

Topics: Amides; Animals; Atrial Fibrillation; Cardiac Pacing, Artificial; Disease Models, Animal; Dogs; Echocardiography; Female; Fibrosis; Fumarates; Gene Expression; Heart Atria; Hemodynamics; Renin; Renin-Angiotensin System

Change in NT-proBNP level is a common surrogate endpoint in early phase heart failure (HF) trials, but whether this endpoint is influenced by atrial fibrillation/flutter (AFF) is unclear.. This analysis included 1358 patients from the ASTRONAUT trial, which randomized patients hospitalized for HF with EF ≤40% to aliskiren or placebo in addition to standard care. Patients were stratified by presence of AFF on baseline ECG. NT-proBNP was measured longitudinally by a core laboratory at baseline, 1 month, 6 months, and 12 months. Compared with non-AFF patients, AFF patients experienced greater reduction from baseline in log-transformed NT-proBNP (interaction P < 0.001), but this difference was not significant after adjustment (interaction P = 0.726). The ability of aliskiren to lower NT-proBNP during follow-up differed by AFF status (interaction P = 0.001), with aliskiren lowering NT-proBNP more than placebo among non-AFF patients only. After adjustment, baseline AFF was not associated with mortality or HF hospitalization at 12 months (all P ≥ 0.152).. In this hospitalized HF cohort, AFF status did not influence post-discharge NT-proBNP trajectory or clinical outcomes after adjustment for patient characteristics. Aliskiren lowered follow-up NT-proBNP levels in patients without AFF, but had no influence among patients with AFF. This study generates the hypothesis that the ability of a HF trial to meet an NT-proBNP defined endpoint may be influenced by the prevalence of AFF in the population. Because aliskiren did not improve outcomes in patients without AFF, this analysis suggests changes in NT-proBNP induced by investigational therapies may be dissociated from clinical effects.

Topics: Aged; Amides; Antihypertensive Agents; Atrial Fibrillation; Atrial Flutter; Disease Progression; Female; Fumarates; Heart Failure; Hospitalization; Humans; Male; Middle Aged; Natriuretic Peptide, Brain; Peptide Fragments; Prognosis; Randomized Controlled Trials as Topic

Atrial fibrillation (AF) contributing to the increasing mortality risk is the most common disease in clinical practice. Owing to the side effects and relative inefficacy of current antiarrhythmic drugs, some research focuses on renin-angiotensin-aldosterone system (RAS) for finding out the new treatment of AF. The purpose of this study is to confirm whether aliskiren as a proximal inhibitor of renin, which completely inhibits RAS, has beneficial effects on atrial structural remodeling in AF. In this study, rapid atrial pacing was induced at 500 beats per minute for 2 weeks in a canine model. A different dose of aliskiren was given orally for 2 weeks before rapid atrial pacing. HE staining and Masson's staining were used for analysis of myocardial fibrosis. TGF-β1, signal pathways, and pro-inflammatory cytokines were shown for the mechanism of structural remodeling after the treatment of aliskiren. Serious atrial fibrosis was induced by rapid atrial pacing, followed by the elevated TGF-β1, upregulated MEK and ERK1/2, and increased inflammatory factors. Aliskiren could apparently improve myocardial fibrosis by reducing the expression of TGF-β1, inhibiting MEK and ERK1/2 signal pathways, and decreasing IL-18 and TLR4 in both serum and atrial tissue. In conclusion, aliskiren could prevent atrial structural remodeling from rapid atrial pacing for 2 weeks. Aliskiren may play a potential beneficial role in the treatment of AF induced by rapid atrial pacing.

Topics: Action Potentials; Amides; Animals; Anti-Arrhythmia Agents; Atrial Fibrillation; Atrial Remodeling; Cardiac Pacing, Artificial; Cytokines; Disease Models, Animal; Dogs; Extracellular Signal-Regulated MAP Kinases; Female; Fibrosis; Fumarates; Heart Atria; Heart Rate; Inflammation Mediators; Male; MAP Kinase Kinase 1; Renin; Signal Transduction; Transforming Growth Factor beta1

Activation of the atrial renin-angiotensin system plays an important role in the pathophysiology of atrial fibrillation (AF). The pulmonary vein (PV) and left atrium (LA) are important trigger and substrate for the genesis of AF. We investigate the effects of a direct renin inhibitor, aliskiren, on the PV and LA arrhythmogenic activity and the underlying electromechanical mechanisms. Conventional microelectrodes were used to record action potentials and contractility in isolated rabbit PVs and LA tissues before and after the administration of aliskiren (0.1, 1, 3 and 10 μM). By the whole-cell patch clamp and indo-1 fluorimetric ratio techniques, ionic currents and intracellular calcium transient were studied in isolated single PV and LA cardiomyocyte before and after the administration of aliskiren (3 μM). Aliskiren (0.1, 1, 3 and 10 μM) reduced PV firing rate in a concentration-dependent manner (6, 10, 14 and 17%) and decreased PV diastolic tension, which could be attenuated in the presence of 100 μM L-N(G)-Nitroarginine Methyl Ester (L-NAME). Aliskiren induced PV automatic rhythm exit block causing slow and irregular PV activity with variable pauses. Aliskiren increased PV and LA contractility, which could be abolished by pre-treating with 0.1 μM ryanodine. Aliskiren (3 μM) decreased L-type calcium currents, but increased reverse-mode of Na( + )/Ca(2+ ) exchanger currents, intracellular calcium transients, and sarcoplasmic reticulum calcium content in PV and LA cardiomyocytes. Pretreatment with renin, losartan or angiotensin II did not alter the effect of aliskiren on sarcolemmal calcium flux. In conclusion, aliskiren reduces PV arrhythmogenic activity with a direct vasodilatory property and has a positive inotropic effect on cardiomyocytes. These findings may reveal the anti-arrhythmic and anti-heart failure potentials of aliskiren.

Topics: Action Potentials; Amides; Animals; Anti-Arrhythmia Agents; Atrial Fibrillation; Calcium; Excitation Contraction Coupling; Fumarates; Heart Atria; Myocardial Contraction; Organ Culture Techniques; Patch-Clamp Techniques; Pulmonary Veins; Rabbits; Renin