Low-Energy Internal Cardioversion for Atrial Fibrillation Resistant to External Cardioversion

Internal Cardioversion. introduction : This report describes the electrical conversion of atrial fibrillation in two morbidly obese patients refractory to external cardioversion at 360 J.
Methods and Results : The two patients were lightly sedated and underwent placement of decapolar catheters in the coronary sinus and right atrial appendage. All ten electrodes of each decapolar catheter were electrically coupled, and defibrillation was attempted at successively increasing levels using a biphasic decaying exponential waveform generated by an external defibrillator. Both patients were returned to normal sinus rhythm using <10 J without complication.
Conclusion : Internal cardioversion is effective in restoration of sinus rhythm in some patients refractory to conventional forms of therapy     

Maintenance of Sinus Rhythm after Cardioversion of Atrial Fibrillation in Patients with Lone Atrial Fibrillation and Patients with Hypertension

Background: The success rate and prognosis of cardioversion of atrial fibrillation (AF) in patients with organic heart disease is well known. In contrast, little data exist about cardioversion success and maintenance of sinus rhythm (SR) in patients with lone AF and in patients with hypertension as the only underlying cardiovascular disease. Methods: In a prospective cardioversion registry 148 of 181 patients (81.8%) with lone AF (age 58 ± 13 years, duration of AF 7.6 ± 19 weeks) and 120 of 148 patients (81.1%) with hypertension (age 62 ± 10 years, duration of AF 6.6 ± 21 weeks) had successful cardioversion and were followed for 7.7 ± 1.9 months. Results: At follow-up, 120 patients (81.1%) with lone AF were in SR, and 18 of these patients had had repeated cardioversion during follow-up (AF total recurrence rate 31.1%). In stepwise regression analysis, the number of previous cardioversions was predictive of rhythm at follow-up (P = 0.0453). Rhythm at follow-up did not differ between patients who were or were not on antiarrhythmic drugs. At follow-up 96 patients (80%) with hypertension were in SR, and 9 of these had had repeated cardioversion during follow-up (AF total recurrence rate 27.5%). As in lone AF, the recurrence rate of AF did not differ between patients with or without antiarrhythmic drug treatment, and in multivariate regression analysis, the number of previous cardioversions was the only clinical predictor of rhythm at follow-up (P = 0.0284). Conclusions: Even in patients with such benign conditions as lone AF or hypertension as the only underlying disease, the prognosis of cardioversion in terms of maintenance of SR is poor. Future studies of rhythm control versus rate control need to include not only patients with organic heart disease but also patients with lone AF and patients with hypertension, since the long-term benefits of these two strategies remain unclear even in these subsets of patients.     

Transient Symptomatic Severe Mitral Regurgitation after Electric Cardioversion of Atrial Fibrillation

Introduction: After electric cardioversion (EC), several cases of cardiac stunning with cardiogenic shock have been reported. Several hypotheses have been proposed, including stunning of the left ventricle (LV) and modifications in the LV conformation that could lead to severe mitral regurgitation (MR). We report 2 cases of cardiogenic shock with severe MR after EC for atrial fibrillation (AF). Case 1: A 75‐year‐old man presented with AF. A transesophageal echocardiography before the EC showed moderate MR. Shortly after successful EC, the patient developed a cardiogenic shock. The transthoracic and a transesophageal echocardiography showed severe MR. Four days later, an echocardiography showed recovery of MR to a moderate grade. Case 2: An 85‐year‐old woman with a history of percutaneous aortic valve replacement presented with AF. After EC, she developed a cardiogenic shock. The transthoracic echocardiography showed severe MR. After recovery, the echocardiography showed moderate MR. Discussion: Cardiac stunning after EC is well known and could explain the development of severe MR due to restrictive movement of leaflets. The transient character of the MR favors a functional origin with an alteration in the geometry of the mitral apparatus. Some cases of so‐called “eclipsed MR” are described in the literature, however, independently to electric shocks. Conclusion: In some patients, flash pulmonary edema seems to be due to transient severe functional MR, although the exact underlying physiopathologic mechanism remains unclear. An ischemic origin with papillary muscle dysfunction due to transient low perfusion could also be advocated.     

Evaluation of Atrial Refractoriness and Atrial Fibrillation Inducibility Immediately after Internal Cardioversion in Patients with Chronic Persistent Atrial Fibrillation

Summary. Objective: To prospectively evaluate right atrial refractoriness and sustained atrial fibrillation (AF) inducibility at programmed electrical stimulation in two groups of patient: a series of patients with chronic persistent AF, studied immediately after successful low energy internal atrial cardioversion, and a group of control patients without history of supraventricular arrhythmias.Patients: Nineteen patients with chronic persistent AF (mean AF duration 11 ± 10 months, range 2–61 months) submitted to successful internal low energy atrial cardioversion in fully conscious state and 11 control patients without history of supraventricular arrhythmias.Methods: An electrophysiological evaluation was performed to measure atrial refractoriness and AF inducibility, by delivering single atrial extrastimuli in high right atrium, at decremental coupling, during spontaneous sinus rhythm and after 8 beats at 600, 500, 400 and 330 ms cycle length. If sustained AF was induced the protocol was terminated.Results: During programmed atrial stimulation sustained AF was induced in 8 out 19 (42%) of the AF patients but in none of the control group. Atrial effective refractory period was significantly shorter in AF patients compared to controls both at basic cycle length, at 600 ms, 500 ms and 400 ms cycle length, meanwhile no statistically significant differences were found at 330 ms cycle length. An altered relationship between atrial effective refractory period and cycle length was found in AF patients compared to controls: the slope of linear correlation slope was significantly lower in AF group than in controls (0.04 ± 0.07 vs 0.17 ± 0.10, p < 0.002).Conclusions: Marked abnormalities of atrial refractoriness and of its heart rate relationship are observed after internal cardioversion of chronic persistent AF in humans and these abnormalities are associated with an high vulnerability to AF. These observations may explain the high risk of AF recurrences in the early phases following successful cardioversion. In this scenario antiarrhythmic drug therapy seems to be mandatory for reducing arrhythmia relapses.     

Outcomes in Patients Requiring Cardioversion Following Catheter Ablation of Atrial Fibrillation

Outcomes of Cardioversion Post AF Ablation.   Introduction: Early recurrence of atrial tachyarrhythmias is commonly noted after catheter ablation of atrial fibrillation (AF). The long-term outcomes of patients who require cardioversion for persistent AF after AF ablation is not known. This study reports the outcomes of patients who underwent cardioversion for persistent AF or atrial flutter following an AF ablation procedure.
Methods: The patient population comprised 55 patients (mean age 58 ± 10 years, 35% paroxysmal) who underwent catheter ablation of AF and subsequently required electrical cardioversion for persistent AF (45 patients) or atrial flutter (10 patients). Cardioversion was defined as early (within 90 days of the ablation procedure) or late (between 90 and 180 days following ablation).
Results: The mean follow-up duration was 15 ± 8 months. Forty-six of the 55 patients (84%) patients experienced recurrence during follow-up. The average time to recurrence after cardioversion was 37 days. Of the 55 patients, 8 (15%) patients had a complete success, 11 (20%) patients had a partial success and 36 patients (65%) had a failed outcome. Seven of the 43 patients (16%) who underwent early cardioversion had a complete success as opposed to one of 12 patients (8%) who underwent late cardioversion (P = 0.49).
Conclusions: This study shows that >80% of patients who undergo cardioversion for persistent AF or atrial flutter after AF ablation have recurrence. The timing of cardioversion did not affect the outcome. These findings allow clinicians to provide realistic expectations to patients regarding the long-term outcome and/or requirement for a second ablation procedure. (J Cardiovasc Electrophysiol, Vol. 21, pp. 27–32, January 2010)     

心房颤动经静脉低能量电复律的应用现状

心房颤动 (AF)是临床常见的慢性或反复发作性快速心率失常之一。近年来 ,AF的药物与非药物治疗均取得较大进展 ,尤其是在 AF的电学治疗方面。本文主要介绍 AF经静脉低能量电复律的应用现状。1　AF复律治疗的指征与方法选择AF不是一种“良性”心律失常 ,需要临床积极处理。复律治疗是 AF的最佳处理措施 ,它可产生一系列临床效益[1,2 ] 。但在决定给 AF病人施行复律治疗前 ,应估计复律成功的可能性、复律治疗的症状改善程度和远期效果。复律后 AF的复发率与复律前 AF的持续时间密切相关。复律前 AF持续时间 >2年者 ,复律后 6～ 1 2个…     

Internal Cardioversion of Chronic Atrial Fibrillation

Chronic atrial fibrillation (AF), a common arrhythmia in clinical practice presents the danger of systemic embolization and an untoward effect on cardiac function. Furthermore, in occasional patients symptoms related to rapid ventricular response, resistant to bradycardiac agents, may lead to electrical ablation of the atrioventricular junction. A new technique of internal cardioversion of AF is described. It consists of delivering high energy shocks (200–400 joules) between the proximal electrode of a quadripolar catheter (cathode) and a backplate (anode). The catheter is positioned in the tricuspid valve area and pulled back just inferior to the site of the His bundle recording. This technique was performed in 24 patients. In all patients external cardioversion failed to restore sinus rhythm. All patients complained of symptoms despite antiarrhylhmic therapy. Sinus rhythm was restored by internal cardioversion in 20 of the 24 patients (83%). However, AF recurred in 7 of the 20 patients before hospital discharge. The only complication noted was transient atrioventricular block in 9 patients treated with prophylactic ventricular pacing. Of the 13 patients who were in sinus rhythm at the time of hospital discharge, 6 patients (46%) remained on stable sinus rhythm. Recurrence of atrial fibrillation was noted in the remaining 7 patients, in 4 within the first 4 months and in 3 patients 8, 9 and 18 months, respectively, after the procedure. A second attempt of internal cardioversion was performed in 3 and was successful in 2. With a follow-up ranging from 13 to 37 months (mean 25 months), 6 patients (49%) are in sinus rhythm. This study suggests that internal cardioversion may be useful in selected patients with chronic AF.     

Cardioversion Related Thromboembolism: Value of Transesophageal Echocardiography to Guide Cardioversion in Patients with Atrial Fibrillation

The aim of this article is to review two recent investigations of the value of transesophageal echocardiography to guide direct current cardioversion in different patient populations. In the Ludwigshafener Observational Cardioversion Study (LOCS) a TEE was performed prior to electrical cardioversion in patients with atrial fibrillation who had been receiving oral anticoagulation adjusted to an international normalized ratio of 2 to 3 for at least three weeks. In contrast, the ACUTE study investigated the value of transesophageal echocardiography in patients with atrial fibrillation in whom long-term oral anticoagulants had not been initiated in comparison to standard anticoagulation therapy. Furthermore, the following questions in respect to anticoagulation therapy are addressed: (1) how should patients be approached for pharmacological or spontaneous conversion; (2) how to treat emergency situations, (3) what is the importance of the postcardioversion period and long-term anticoagulation therapy; and (4) what is the role of low molecular weight heparin in the pericardioversion period.     

Early Reinitiation of Atrial Fibrillation Following External Electrical Cardioversion in Amiodarone-Treated Patients

Early reinitiation of atrial fibrillation (ERAF) following external or internal electrical cardioversion is one of the factors determining unsuccessful electrical cardioversion. Prevention of ERAF has not been studied systematically in patients on amiodarone therapy. Methods and Results: 22 patients had ERAF within 1[emsp4 ]min after external electrical cardioversion of atrial fibrillation. 11 patients were on amiodarone therapy and 11 patients had no antiarrhythmic medication. The effect of atropine, post-shock atrial pacing and intravenous ajmaline on ERAF was consecutively tested in these patients. Administration of atropine before repeated defibrillation or post-shock atrial pacing prevented ERAF in 9 of the 11 patients (82%) on amiodarone therapy but in only 3 of 11 patients (27%) without amiodarone (p<0.05). In the remaining patients, intravenous ajmaline was effective in the suppression of ERAF in 5 patients without amiodarone and in 1 patient with amiodarone. The PP interval preceding the atrial premature beat reinitiating atrial fibrillation was nonsignificantly longer in amiodarone-treated patients (1127±419[emsp4 ]ms) in comparison to patients without amiodarone (896±271[emsp4 ]ms). 27% of patients without amiodarone at the time of electrical cardioversion and 55% of patients with amiodarone remained in sinus rhythm during the follow-up of 29±14 and 30±14 months, respectively. Conclusions: ERAF in patients on amiodarone can be treated by atropine or atrial pacing to prevent bradycardia-dependent ERAF. ERAF in amiodarone-treated patients does not apparently predict late recurrence of atrial fibrillation on continued amiodarone therapy.     

Efficacy and Safety of Ibutilide for Chemical Cardioversion of Atrial Fibrillation and Atrial Flutter in Cancer Patients

BackgroundAtrial fibrillation and atrial flutter (AF/AFL) are the most common arrhythmias encountered in clinical practice. Rate versus rhythm control remains a difficult decision, especially in the acute setting. ibutilide is a class iii antiarrhythmic indicated for pharmacological cardioversion of recent-onset AF/AFL. At the University of Texas MD Anderson Cancer Center, restoration of sinus rhythm is desirable because many patients have contraindications to anticoagulation. In addition, most are on multiple medications that prolong the QT interval; therefore, the objective of this study was to establish the safety and efficacy of ibutilide.MethodsThis was a retrospective chart review of 81 patients who were identified via the pharmacy database as receiving ibutilide for AF/AFL from January 2002 to May 2006. Outcomes including cardioversion rates and effects on the QT interval were recorded.ResultsIbutilide use was associated with successful cardioversion in 75% of patients. Out of 81 patients, 68 patients (84%) were on at least 1 medication that prolonged the QT interval at the time of ibutilide administration. However, no significant changes in the corrected QT interval pre and post ibutilide cardioversion were noted in any group of patients.ConclusionsOverall, ibutilide is safe and effective in cancer patients when used for acute cardioversion of AF/AFL. Despite the use of multiple medications that can potentially prolong the QT interval, no patient experienced serious life-threatening rhythm disturbances or significant QT prolongation during ibutilide administration.     

Adverse Events Associated With Electrical Cardioversion in Patients With Acute Atrial Fibrillation and Atrial Flutter

BackgroundWe sought to evaluate safety of electrical cardioversion (ECV) for patients with acute atrial fibrillation (AF) or atrial flutter (AFL) in the emergency department (ED).MethodsThis was an analysis of data from 4 multicentre AF/AFL studies conducted from 2008 to 2019 at 23 large EDs. We included adult patients who received attempts at ECV and who had presented acutely after symptom onset. Staff manually reviewed study and clinical records to abstract data.ResultsWe evaluated 1736 ECV cases with a mean age of 60.1 years and 67.1% male. The overall success of ECV was 90.2% (95% confidence interval 88.7%-91.6%), with 4.9% of patients admitted. ED physicians performed the ECV in 95.2% and provided sedation in 96.5%; 13.9% (12.3%-15.7%) of cases experienced important adverse events that required treatment, and 0.4% were classified as life threatening. Another 5.6% had adverse events that did not require treatment. Logistic regression found that the RAFF-3 study cohort (odds ratio [OR] 2.0), age ≥ 85 years (OR 2.1), coronary artery disease (OR 1.5), midazolam (OR 1.9), and fentanyl (OR 1.5) were associated with important adverse events.ConclusionsThis large evaluation of the safety of ECV for acute AF/AFL in the ED found that while serious adverse events were rare, there were a concerning number of events following sedation that required intervention. Physicians should be aware that older age, coronary artery disease, and fentanyl are associated with higher risks of important adverse events. This study provides more information for shared decision making discussions with patients when choosing between drug-shock and shock-only cardioversion strategies.     

Catheter Ablation for Long-Standing Persistent Atrial Fibrillation in Patients Who Have Failed Electrical Cardioversion

Ablation outcomes in 22 consecutive long-standing persistent atrial fibrillation (LPAF) patients with failed direct current cardioversion (DCCV; group 1) were compared with findings in 22 consecutive LPAF patients who had successful DCCV (control 1) and 22 consecutive patients with paroxysmal atrial fibrillation (AF; control 2). All patients underwent a stepwise progressive ablation protocol (pulmonary vein isolation, ablation of complex fractionated atrial electrogram, and repeat ablation of any induced atrial tachycardias). Over 18-month follow-up, 59 % of group 1 patients remained in sinus rhythm without recurrent AF, compared to 64 % and 77 % in controls 1 and 2, respectively. The procedure time was longer in LPAF with a higher procedure complication risk in these 44 LPAF patients (5 % vs. 0 %) than in patients with paroxysmal AF. Our data suggest that catheter ablation provides a practical treatment option with moderate efficacy for restoring sinus rhythm in LPAF patients after failed DCCV.     

Quinidine for Pharmacological Cardioversion of Atrial Fibrillation: A Retrospective Analysis in 501 Consecutive Patients

Background: Although quinidine has been used to terminate atrial fibrillation (AFib) for a long time, it has been recently classified to be used as a third‐line‐drug for cardioversion. However, these recommendations are based on a few small studies, and there are no data available of a larger modern patient population undergoing pharmacological cardioversion of AFib. Therefore, we evaluated the safety of quinidine for cardioversion of paroxysmal AFib in patients after cardiac surgery and coronary intervention. Methods: In 501 consecutive patients (66 ± 9 years, 32% women), 200–400 mg of quinidine were administered every 6 hours until cardioversion or for a maximum of 48 hours. Patients were included with QT interval ≤450 ms, ejection fraction (EF) ≥35%, and plasma potassium >4.3 mEq/L. Exclusion criteria were: unstable angina, myocardial infarction <3 months, and advanced congestive heart failure. Patients received verapamil, beta‐blockers, or digitalis to slow down ventricular rate <100 bpm. Results: Quinidine therapy did not have to be stopped due to adverse drug reactions (ADR), and no significant QTc interval prolongation (Bazett and Fridericia correction) and no life‐threatening ventricular arrhythmia occurred. Mean quinidine dose was 617 ± 520 mg and 92% of the patients received verapamil or beta‐blocker to decrease ventricular rate. Cardioversion was successful in 84% of patients. All ADRs were minor and transient. Multivariate analysis revealed female gender (OR 2.62, CI 1.61–4.26, P < 0.001) and EF 45–54% (OR 1.97, CI 1.15–3.36, P = 0.013) as independent risk factors for ADRs. Conclusions: Quinidine for pharmacological cardioversion of AFib is safe and well tolerated in this subset of patients.