The efficacy of antiarrhythmic drugs in the prevention of recurrence of aconitine-induced atrial fibrillation after electrical conversion

1970 ◽  
Vol 48 (2) ◽  
pp. 90-97 ◽  
Author(s):  
Jeffrey E. Byrne ◽  
Peter E. Dresel
Keyword(s):  
Atrial Fibrillation ◽  
Right Atrium ◽  
Left Atrial ◽  
Antiarrhythmic Drugs ◽  
Capacitor Discharge ◽  
Rapid Injection ◽  
The Right ◽  
Slow Rhythm ◽  
Prevention Of Recurrence ◽  
Atrial Rhythm

We have developed an experimental model to assess the ability of drugs to maintain slow supraventricular rhythm after electrical conversion of atrial fibrillation. Fibrillation was produced by application of a saturated solution of aconitine to the surface of the right atrium of open-chest dogs. Right and left atrial electrograms, the lead II electrocardiogram, and blood pressure were recorded. A capacitor discharge (30 watt-seconds) was applied through electrodes placed on the right atrium and the left ventricle. Atrial rhythm was improved for 1 to 20 s following defibrillation; then atrial fibrillation returned owing to the continued presence of aconitine. Quinidine in doses up to 4 mg/kg did not convert the arrhythmia but increased the duration of recovery after defibrillation up to 49 s. Pronethalol in doses up to 8 mg/kg and propranolol in doses up to 0.8 mg/kg occasionally converted atrial fibrillation to normal rhythm, but had no effect upon the duration of recovery after defibrillation. Diphenylhydantoin was tested in doses up to 20 mg/kg. Rapid injection of doses above 10 mg/kg slowed or converted the arrhythmia. Slow injections of diphenylhydantoin had no direct effect on the atrial fibrillation, but the period of recovery after defibrillation was prolonged up to 700 s. These experiments show that drugs can enhance the ability of the heart to maintain a slow rhythm following electrical conversion of atrial fibrillation. Those agents which most effectively convert atrial fibrillation are not the most effective agents for preventing the return of fibrillation after conversion.

Levels of platelet derived extracellular vesicles in the left atrial appendage are higher in patients with permanent atrial fibrillation

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Zietzer ◽  
B Al-Kassou ◽  
P Jamme ◽  
E Steffen ◽  
N Werner ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Extracellular Vesicles ◽  
Platelet Activation ◽  
Right Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Thrombus Formation ◽  
Atrial Appendage ◽  
Funding Source ◽  
The Right

Abstract Introduction Atrial fibrillation (AF) is a frequent arrhythmic disease and one of the most important causes of thrombembolic disease due to intracardiac thrombus formation. The left atrial appendage has been identified as the structure, where thrombus formation typically takes place in AF patients. Previous studies have shown thrombus formation is more frequent in permanent, than in paroxysmal or persistent AF. Underlying causes for this finding, however, remain unclear. Recently, it has been shown, that large extracellular vesicles (Microvesicles, MVs) are mediators of platelet activation. The aim of this study is therefore to investigate if the AF subtype correlates with the regional abundance of platelet derived MVs in the left atrial appendage. Methods and results In order to address this question blood samples from 59 consecutive patients undergoing left and right atrial catheterization were collected from the right atrium (RA), the left atrium (LA) and the left atrial appendage (LAA). 49% of the patients had permanent AF, 34% had non-permanent AF and 17% had no history of AF. MVs were isolated from 150 μL citrate plasma by a four-step differential centrifugation protocol (20000g x 40 min as main pelleting step). The MVs were characterized by immunoblotting and nanoparticle tracking analysis. The size of the MVs ranged between 50 and 600 nm and the MVs were shown to carry typical markers such as Annexin V. For flowcytometric analysis and quantification, Calcein AM was used to identify vesicles and CD31-PE, CD41-APC, CD235a-PE-Cy7 were applied to differentiate between platelet-derived MVs (PMVs, CD41+ CD31+), endothelial cell-derived MVs (EMVs, CD41- CD31+) and Red blood cell-derived MVs (RMVs, CD235a+). Fluorescence minus one controls, a concentration row and detergent mediated degradation were used to confirm specific staining of MVs. Total MV numbers (Calcein + events) did not differ significantly between the three cardiac localizations. In the left atrial appendage, the proportion of PMV was significantly higher in permanent AF patients compared to non-permanent AF. EMV numbers only differed in the right atrium, where permanent AF patients exhibited significantly lower numbers of EMVs compared to no AF controls. No differences between the groups were detected for RMV. Conclusion In the present study, we found that PMV levels in the left atrial appendage correlate with the type of atrial fibrillation (permanent vs non-permanent). PMVs have been connected to platelet activation and thrombus formation. These results may help to better understand how different types of atrial fibrillation cause different rates of thrombus formation in the LAA. PMV and EMV numbers by AF subtype Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Medical Faculty University Bonn

scholarly journals Left atrial vagal stimulation resulting in atrial fibrillation driven from the right atrium

EP Europace ◽  
2008 ◽  
Vol 10 (10) ◽  
pp. 1248-1249
Author(s):  
S. Knecht ◽  
M. Wright ◽  
M. Haissaguerre
Keyword(s):  
Atrial Fibrillation ◽  
Right Atrium ◽  
Left Atrial ◽  
Vagal Stimulation ◽  
The Right

scholarly journals A prospective randomized trial comparing biatrial and isolated left atrial ablation in patients with long-standing persistent atrial fibrillation undergoing CABG

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Kalybekova ◽  
A Chernyavskyi ◽  
V Lukinov
Keyword(s):  
Atrial Fibrillation ◽  
Right Atrium ◽  
Left Atrial ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Persistent Atrial Fibrillation ◽  
Coronary Syndrome ◽  
Atrial Ablation ◽  
The Right

Abstract Purpose To compare the efficacy and safety of left atrial ablation (LAA) with those of biatrial ablation (BA) in patients with long-standing persistent atrial fibrillation (AF) in common with CABG. Background AF is the most common heart rhythm disorder, while CAD is the most common cardiovascular disease. Chronic coronary syndrome and atrial fibrillation coexist in many patients. Long-standing persistent atrial fibrillation (AF) is frequent pathology in patients undergoing CABG. Surgical ablation in such patients is currently an effective treatment of AF. Pulmonary vein isolation (PVI) may reduce AF recurrences in 70% of patients with paroxysmal form of AF. However, the efficacy of ablation in patients with long-standing persistent AF is rather low. Clinical studies have shown that the right atrium can also be involved in the AF initiation and maintenance. Areas localized in both atrias are characterized by rapid electrical activity, which is critical in the AF persistence. Therefore, we have hypothesized that in long-standing persistent AF BA could be more effective than isolated LAA. Methods Between 2016 and 2019, 116 patients with long-standing persistent AF and CAD who underwent open-heart surgery were included in this single blind prospective randomized study and divided into two groups: 58 patients in group 1 underwent isolated LAA + CABG, and group II (58 patients) - BA + CABG. All the patients had Reveal LINQ ICM System (Medtronic, USA) implanted during the index procedure. The mean age was 65 [61; 67.75] years versus 62 [58; 66] years (p=0.050) and 83% versus 84% (p>0.999) were men in BA and LAA groups, respectively. The follow-up time was 22±3 months for two groups. The primary endpoint was freedom from AF during 24-month follow-up based on 24-hour Holter monitoring ECG registration and Reveal device data. Results This study has demonstrated that in CAD patients with long-standing persistent AF, PVI in combination with multiple linear lesions in the right atrium while GABG produce a significantly higher success rate than PVI alone. After 24 months, AF recurred in 38% of patients in the BA group and in 64% – in the LAA group (p=0.010). Univariate logistic regression analysis showed indicators as long axis of left atria in mm (OR 3.45, 95%; CI 1.77 to 7.64, p=0.001) in LAA group and (OR 2.02, 95%; CI 1.03 to 4.26, p=0.049) in-group BA increases the risk of AF. Chronic kidney disease (OR 2.95, 95% CI 1.05 to 9.22, p=0,048), and mitral regurgitation (OR 1.18, 95% CI 1.01 to 1.41, p=0.047) have been found the independent predictors of AF recurrence in the LAA group. Arrhythmia on the third day after procedure increases the risk of AF (OR 3.79, 95% CI 1.45 to 10. 58, p=0.008) in the LAA group in a long-term follow-up. Conclusion The study has demonstrated that BA is more effective for treatment of long-standing persistent AF in CAD patients undergoing CABG. Funding Acknowledgement Type of funding source: None

Abstract 18601: Impact of Right and Left Atrial Remodeling on Outcomes From Atrial Fibrillation Rotor Ablation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Amir Schricker ◽  
Tina Baykaner ◽  
Junaid Zaman ◽  
Gautam Lalani ◽  
Kenneth Hopper ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Structural Changes ◽  
Unknown Etiology ◽  
Atrial Remodeling ◽  
Left Atrial Remodeling ◽  
Single Procedure ◽  
Clinical Indices ◽  
The Right

Introduction: Targets for the ablation of atrial fibrillation (AF) are debated. In particular, recent studies questioning fractionated electrograms and lines has increased focus on AF substrates of rotors and focal impulses. These AF sources are seen in both atria, but have unknown etiology. We hypothesized that differential remodeling between the right atrium (RA), whose structural changes are largely undefined, and left atrium (LA) influence the distribution of AF sources and the outcomes from AF source ablation. Methods: In 60 patients at AF ablation (62±10 years, 60% persistent, 5% long-standing persistent), we compared size differences between RA and LA to the number of sources in each chamber and outcomes from AF source-guide ablation. We studied if a 64-pole basket differentially fit the LA or RA, judged by deformation of its splines by the atria (fig. A, B) over multiple cardiac cycles on fluoroscopy. Ablation targeted sources in both atria and was followed by PVI, with follow-up per guidelines. Results: Using baskets in both atria, 205 sources (LA 138; RA 67) were identified and ablated. Notably, the same basket in each patient was dynamically deformed by RA in 51 (85%) of cases but in the LA in only 39 (65%), indicating greater LA remodeling. The number of AF sources was higher in the presence of basket deformation of RA (n=174) than LA (n=130). LA deformation correlated with LVEF (p=0.05). Freedom from AF at 1 year was reduced in patients with no basket deformation (i.e. dilation) in LA (p=0.07) or RA (p=0.06). Notably, single procedure AF freedom was substantially lower in patients with differential remodeling (deformation in only 1 chamber) of 84% vs. 60% (fig C). Conclusions: Structural atrial remodeling influences the number of electrical rotors and focal sources in each chamber. A mismatch between right and left atrial remodeling predicts lower success from rotor ablation. These data also provide novel clinical indices of effective basket positioning.

scholarly journals Thoracoscopic surgical atrial fibrillation ablation in patients with an extremely enlarged left atrium

2021 ◽  
Author(s):  
Jolien Neefs ◽  
Robin Wesselink ◽  
Nicoline W. E. van den Berg ◽  
Jonas S. S. G. de Jong ◽  
Femke R. Piersma ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Antiarrhythmic Drugs ◽  
Primary Outcome ◽  
Volume Index ◽  
Substantial Part ◽  
Atrial Tachyarrhythmia ◽  
Af Ablation ◽  
Male Patients

Abstract Purpose Efficacy of pulmonary vein isolation (PVI) for atrial fibrillation (AF) decreases as left atrial (LA) volume increases. However, surgical AF ablation with unknown efficacy is being performed in patients with a giant LA (GLA). We determined efficacy of thoracoscopic AF ablation in patients with compared to without a GLA. Methods Patients underwent thoracoscopic PVI with additional left atrial ablations lines (in persistent AF) and were prospectively followed up. GLA was defined as LA volume index (LAVI) ≥ 50 ml/m2. Follow-up was performed with ECGs and 24-h Holters every 3 months. After a 3-month blanking period, all antiarrhythmic drugs were discontinued. The primary outcome was freedom of any atrial tachyarrhythmia ≥ 30 s during 2 years of follow-up. Results At baseline, 68 (15.4%) patients had a GLA (LAVI: 56.7 [52.4–62.8] ml/m2), while 374 (84.6%) had a smaller LA (LAVI: 34.8 [29.2–41.3] ml/m2). GLA patients were older (61.9 ± 6.9 vs 59.4 ± 8.8 years, p = 0.02), more often diagnosed with persistent AF (76.5% vs 58.6%, p = 0.008). Sex was equally distributed (with approximately 25% females). GLA patients had more recurrences compared to non-GLA patients at 2-year follow-up (42.6% vs 57.2%, log rank p = 0.02). Freedom of AF was 69.0% in non-GLA paroxysmal AF patients compared to 43.8–49.3% in a combined group of GLA and/or persistent AF patients(log rank p < 0.001). Furthermore, freedom was 62.4% in non-GLA male patients, compared to 43.8–47.4 in a combined group of GLA and/or female sex(log rank p = 0.02). Conclusion Thoracoscopic AF ablation is an effective therapy in a substantial part of GLA patients. Thoracoscopic AF ablation may serve as a last resort treatment option in these patients.

Acetylcholine release by a stimulus train lowers atrial fibrillation threshold

1987 ◽  
Vol 253 (4) ◽  
pp. H863-H868 ◽  
Author(s):  
D. E. Euler ◽  
P. J. Scanlon
Keyword(s):  
Atrial Fibrillation ◽  
Action Potential ◽  
Right Atrium ◽  
Single Pulse ◽  
Monophasic Action Potential ◽  
Adrenergic Blockade ◽  
The Right ◽  
Alpha Chloralose ◽  
Electrical Stimuli ◽  
Local Release

This study was designed to evaluate the importance of local release of autonomic neuromediators when electrical stimuli are applied to the right atrium to measure the atrial fibrillation threshold (AFT). Experiments were performed in 16 open-chest dogs anesthetized with alpha-chloralose. The dogs were denervated by bilateral transection of the stellates and cervical vagi. The AFT was determined in 11 dogs by delivering either a train of stimuli (14 pulses, 4 ms, 100 Hz) or a single stimulus (10 ms) to the right atrium during its vulnerable period. In eight dogs, beta-adrenergic blockade with timolol (0.1 mg/kg) had no effect on the AFT determined with either method. Atropine (0.2 mg/kg), given after timolol, significantly increased the train-of-pulses AFT from 4.7 +/- 0.4 to 32.3 +/- 4.6 mA (P less than 0.001). The single-pulse AFT increased from 16.5 +/- 1.5 to 17.8 +/- 1.5 mA (P less than 0.05). Atropine had a similar effect on the AFT when it was given in the absence of timolol (n = 3). In five additional dogs, a monophasic action potential was recorded while a 10-mA train was delivered to the atrium during its absolute refractory period. There was marked shortening of the monophasic action potential duration (55 +/- 6 ms) in the first beat after the train. The shortening was totally abolished by atropine (0.2 mg/kg). The results suggest that a train of stimuli liberates local stores of acetylcholine, which cause a shortening of atrial repolarization time and a profound decrease in the current necessary to evoke fibrillation.

Electrophysiological and Electroanatomical Mapping of the Right Atrium in Persistent Atrial Fibrillation: Relation to Collagen Turnover

2015 ◽  
Vol 38 (9) ◽  
pp. 1039-1048 ◽  
Author(s):  
CHRISTOS A. GOUDIS ◽  
ELEFTHERIOS M. KALLERGIS ◽  
EMMANUEL M. KANOUPAKIS ◽  
HERCULES E. MAVRAKIS ◽  
NIKI E. MALLIARAKI ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Right Atrium ◽  
Persistent Atrial Fibrillation ◽  
Electroanatomical Mapping ◽  
Collagen Turnover ◽  
The Right
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