Internal low-energy cardioversion: a therapeutic option for restoring sinus rhythm in chronic atrial fibrillation after failure of external cardioversion.

AIMS: Conventional external cardioversion remains the technique of choice for restoration of sinus rhythm in patients with chronic atrial fibrillation (AF). Recent reports have suggested that internal low-energy cardioversion is efficient and safe in terminating AF in patients with failed external cardioversion. METHODS AND RESULTS: In 20 of 118 consecutive patients with spontaneous chronic AF (>7/days), who underwent low-energy cardioversion, one or more attempts at restoring sinus rhythm with external cardioversion had failed. Low-energy internal cardioversion was performed under light sedation. Shocks were delivered (using an external custom defibrillator) between two nonapolar catheters positioned in the right atrium (cathode) and in the coronary sinus (anode). Heart disease was present in 12 and absent in eight patients ('lone' atrial fibrillation). Atrial fibrillation was established for a period ranging from 12 days to 53 months. Low-energy internal cardioversion restored sinus rhythm in 15 of the 20 patients (75%) with a mean energy of 4.5+/-1.2 J, a mean conversion voltage of 355+/-53 V and a mean impedance of 63+/-8 ohms. No complications were observed. With a mean follow-up of 6+/-7 months, 11 patients (73%) were in stable sinus rhythm. CONCLUSIONS: This study provides evidence in support of low-energy internal cardioversion as a valuable therapeutic option in patients in whom conventional external cardioversion failed. This technique is safe and does not require general anaesthesia.     

Prediction of maintenance of sinus rhythm after electrical cardioversion of atrial fibrillation by non-deterministic modelling.

AIMS: Atrial fibrillation (AF) is the most common rhythm disorder. Because of the high recurrence rate of AF after cardioversion and because of potential side effects of electrical cardioversion, it is clinically important to predict persistence of sinus rhythm after electrical cardioversion before it is attempted. The aim of our study was the development of a mathematical model by "genetic" programming (GP), a non-deterministic modelling technique, which would predict maintenance of sinus rhythm after electrical cardioversion of persistent AF. PATIENTS AND METHODS: Ninety-seven patients with persistent AF lasting more than 48h, undergoing the first attempt at transthoracic cardioversion were included in this prospective study. Persistence of AF before the cardioversion attempt, amiodarone treatment, left atrial dimension, mean, standard deviation and approximate entropy of ECG R-R intervals were collected. The data of 53 patients were randomly selected from the database and used for GP modelling; the other 44 data sets were used for model testing. RESULTS: In 23 patients sinus rhythm persisted at 3 months. In the other 21 patients sinus rhythm was not achieved or its duration was less than 3 months. The model developed by GP failed to predict maintenance of sinus rhythm at 3 months in one patient and in six patients falsely predicted maintenance of sinus rhythm. Positive and negative likelihood ratios of the model for testing data were 4.32 and 0.05, respectively. Using this model 15 of 21 (71.4%) cardioversions not resulting in sinus rhythm at 3 months would have been avoided, whereas 22 of 23 (95.6%) cardioversions resulting in sinus rhythm at 3 months would have been administered. CONCLUSION: This model developed by GP, including clinical data, ECG data from the time-domain and nonlinear dynamics can predict maintenance of sinus rhythm. Further research is needed to explore its utility in the present or an expanded form.     

心房颤动电转复后左心耳顿抑的预测因子

目的研究非瓣膜病心房颤动(房颤)患者中,心脏电转复后左心耳顿抑的危险因素与预测因子.方法 68例房颤电转复成功患者,分为左心耳顿抑组与对照组,通过单因素及多元逐步逻辑回归分析,将临床和超声影像学指标作为待选变量,对电转复后左心耳顿抑的危险因素进行研究.结果单因素分析发现,左心耳顿抑组与对照组间差异有统计学意义的指标有房颤持续时间[(10.6±15.6)周vs(22.0±20.1)周,P＜0.05]、左心房内径[(43.8±7.7)mm vs(48.5±6.2)mm,P＜0.01)]、左心房排空分数[(0.32±0.08)vs(0.27±0.09),P＜0.05]、左心室射血分数[(0.50±0.06)vs(0.46±0.06),P＜0.01]、最大复律能量[(96.8±65.8)J vs(156.8±100.8)J,P＜0.01]、累积转复能量[(146.8±142.6)J vs(290.5±242.1)J,P＜0.01]和电转复次数[(1.7±0.9)次vs(2.4±1.2)次,P＜0.05].多元逐步逻辑回归分析发现,房颤持续时间(β＝0.105,P＜0.01)、左心房内径(β＝0.196,P＜0.01)、左心室射血分数(β＝-20.549,P＜0.01)、转复累积能量(β＝0.004,P＜0.05)是左心耳顿抑的独立危险因素.结论房颤持续时间、左心房内径、左心室射血分数和累积复律能量是房颤电转复后左心耳顿抑的独立预测因子.     

心房颤动电复律的相关因素

目的分析影响心房颤动电复律成功的因素。方法根据房颤患者62例电复律是否成功,分为复律成功组和失败组。比较两组在性别、年龄、并发冠心病、高血压病和瓣膜性心脏病、左心房内径、左心室舒张末期内径、左心室射血分数、C反应蛋白（CRP）水平的差异。CRP检测:所有患者于入院后/入组后第2天常规空腹抽血,采用免疫比浊法测定高敏感CRP（hs-CRP）。结果与转复成功组比较,转复失败组年龄大（P<0.05）,左心房内径大（P<0.05）,并发瓣膜性病变比例高（P<0.05）,房颤持续时间长（P<0.05）,hs-CRP水平高（P<0.05）。经多因素分析,hs-CRP水平OR为2.1（95%CI1.4-3.2,P<0.01）、左房直径OR为1.8（95%CI1.2-2.2,P<0.01）和房颤持续时间OR为2.8（95%CI1.6-4.0,P<0.01）。结论hs-CRP、左房直径及房颤持续时间是影响房颤电复律成功的独立预测因素。     

Atrial fibrillatory rate and sinus rhythm maintenance in patients undergoing cardioversion of persistent atrial fibrillation.

AIMS: The study set out to explore whether an index of atrial electrical electrophysiology can be used to predict atrial fibrillation (AF) relapse, and if the predictive properties differ as a result of arrhythmia duration. METHODS AND RESULTS: The study comprised 175 consecutive patients with persistent AF (median duration 94 days, range 2 to 1044) referred for cardioversion. Twenty-nine patients had arrhythmia duration under 30 days (median 5 days, range 2-26). Atrial fibrillatory rate (AFR) was estimated using a frequency power spectrum analysis of QRST-cancelled ECG. At 1-month follow-up, 56% of the patients had relapsed to AF. The pre-cardioversion mean AFR of those patients was 399+/-52 fibrillations per minute (fpm) compared with 363+/-63 fpm among patients maintaining SR (P<0.0001). In patients with short AF duration, the difference was even more pronounced (424+/-52 vs. 345+/-65 fpm, P<0.01). In this group, a finding of an AFR above the mean value of the study population predicted AF relapse with high accuracy. CONCLUSION: In patients undergoing cardioversion of persistent AF, AF relapse is predicted by a higher AFR. A stronger association is seen in patients with short arrhythmia duration, reflecting either rapid remodelling or pre-existing changes in those who relapse to AF.     

Propafenone versus disopyramide for maintenance of sinus rhythm after electrical cardioversion of chronic atrial fibrillation: A randomized,double-blind study

Summary Safety and efficacy of propafenone and disopyramide for long-term maintenance of sinus rhythm after electrical cardioversion was studied in 56 patients with chronic altrial fibrillation (median arrhythmia duration, 5 months). After cardioversion, patients were randomly assigned to receive double-blind propafenone 300 mg tid (25 patients) or disopyramide 250 mg tid (31 patients). Downward dose adjustment was allowed in case of intolerable side effects. The endpoints were arrhythmia recurrence; and side effects not amenable to dose reduction. For patients randomized to propafenone (mean dose, 878±65 mg/day), 66% [95% confidence interval [(CI) 46–85%] and 55% (95% CI, 34–76%) remained in sinus rhythm at 3 and 6 months, respectively (Kaplan-Meier method). Similar figures were found with disopyramide (mean dose, 704±81 mg/day): 71% (95% CI, 54–87%) and 67% (95% CI, 50–84%) at 3 and 6 months, respectively (p=NS). In the patients with a relapse of atrial fibrillation, the ventricular rate while still using the prophylactic agents did not increase significantly compared with precardioversion. However, one patient on disopyramide had an excessively high relapse heart rate (170 vs. 100 beats/min). Side effects were more frequent on disopyramide. Side effects necessitating drug discontinuation occurred in 12 patients: 4 patients (16%) on propafenone and 8 (26%) on disopyramide. Severe adverse effects occurred in two patients, who developed heart failure while on disopyramide. There were no proarrhythmic events or deaths. Thus, propafenone and disopyramide are equally effective for maintaining sinus rhythm after cardioversion of atrial fibrillation. Propafenone is, however, better tolerated than disopyramide, which may cause heart failure.     

Lack of prevention of heart failure by serial electrical cardioversion in patients with persistent atrial fibrillation

OBJECTIVE—To investigate the occurrence of heart failure complications, and to identify variables that predict heart failure in patients with (recurrent) persistent atrial fibrillation, treated aggressively with serial electrical cardioversion and antiarrhythmic drugs to maintain sinus rhythm.DESIGN—Non-randomised controlled trial; cohort; case series; mean (SD) follow up duration 3.4 (1.6) years.SETTING—Tertiary care centre.SUBJECTS—Consecutive sampling of 342 patients with persistent atrial fibrillation (defined as > 24 hours duration) considered eligible for electrical cardioversion.INTERVENTIONS—Serial electrical cardioversions and serial antiarrhythmic drug treatment, after identification and treatment of underlying cardiovascular disease.MAIN OUTCOME MEASURES—heart failure complications: development or progression of heart failure requiring the institution or addition of drug treatment, hospital admission, or death from heart failure.RESULTS—Development or progression of heart failure occurred in 38 patients (11%), and 22 patients (6%) died from heart failure. These complications were related to the presence of coronary artery disease (p < 0.001, risk ratio 3.2, 95% confidence interval (CI) 1.6 to 6.5), rheumatic heart disease (p < 0.001, risk ratio 5.0, 95% CI 2.4 to 10.2), cardiomyopathy (p < 0.001, risk ratio 5.0, 95% CI 2.0 to 12.4), atrial fibrillation for < 3 months (p = 0.04, risk ratio 2.0, 95% CI 1.0 to 3.7), and poor exercise tolerance (New York Heart Association class III at inclusion, p < 0.001, risk ratio 3.5, 95% CI 1.9 to 6.7). No heart failure complications were observed in patients with lone atrial fibrillation.CONCLUSIONS—Aggressive serial electrical cardioversion does not prevent heart failure complications in patients with persistent atrial fibrillation. These complications are predominantly observed in patients with more severe underlying cardiovascular disease. Randomised comparison with rate control treatment is needed to define the optimal treatment for persistent atrial fibrillation in relation to heart failure.     

VERDICT: the Verapamil versus Digoxin Cardioversion Trial: A randomized study on the role of calcium lowering for maintenance of sinus rhythm after cardioversion of persistent atrial fibrillation

INTRODUCTION: Many relapses of atrial fibrillation (AF) occur, especially during the first week(s) after electrical cardioversion (ECV). The aim of the present study was to compare in a randomized design the efficacy of verapamil (intracellular calcium lowering) versus digoxin (calcium increasing) for maintenance of sinus rhythm after ECV. METHODS AND RESULTS: Ninety-seven patients with persistent AF were randomized to verapamil (n = 49) or digoxin (n = 48) for 1 month before and 1 month after ECV. The first month after ECV, patients recorded heart rhythm using daily transtelephonic monitoring. No additional antiarrhythmic drugs were given. Of the 97 patients, 43 patients (20 verapamil) underwent ECV per protocol. Median previous AF duration was 18 and 26 days for verapamil and digoxin, respectively. There were no differences in atrial dimensions and underlying heart disease between the two groups. The success rate of ECV was 75% versus 83% (P = NS). After 1 month, 47% versus 53% (P = NS) had recurrence of AF. Median time to recurrence was 5 days (range 0 to 26) versus 8 days (range 2 to 28) (P = NS), respectively. CONCLUSION: Stand-alone intracellular calcium lowering by verapamil around ECV does not enhance cardioversion outcome.     

Long-short sequence may predict immediate recurrence of atrial fibrillation after external cardioversion.

AIM: We thought, that analysis of surface electrocardiograms recorded immediately after electrical external cardioversion (EC) might enlighten the mechanisms responsible for immediate recurrence of atrial fibrillation (AF) and especially to test whether atrial ectopic beats (PAC) with long-short (LS) sequence are related to the recurrence of arrhythmia after cardioversion in patients with chronic AF. METHODS AND RESULTS: One hundred and thirty-seven patients (mean age 57+/-7 years) undergoing EC for chronic AF entered the study. Evaluation of the patients included clinical history, physical examination, ECG, routine laboratory tests, and transthoracic echocardiography. The cardioversion was performed with monophasic waveform shock and immediately after successful EC, 1 min of recording of the ECG lead II was analysed. One hundred and twenty patients (87%) of 137 patients enrolled in the study had had successful EC and 33 (27%) of them experienced immediate recurrence of AF within 1 min (Group I) and 87 patients had no arrhythmia recurrence (Group II). In group I in 24 patients (73%) recurrence of AF was initiated by PAC with LS sequence. In only 12 of 87 (13%) patients who did not experience immediate recurrence of AF (Group II) PACs were recorded. CONCLUSIONS: Atrial ectopic beats (PACs) with LS sequence, being responsible for AF relapse in about 70% of patients, might predict early re-initiation of arrhythmia after EC. Electrocardiograms, recorded immediately after EC, are a potentially feasible approach in establishing the patterns of AF relapse that may be useful in the management of AF recurrence.     

Low-energy internal cardioversion in patients with long-lasting atrial fibrillation refractory to external electrical cardioversion: results and long-term follow-up.

AIM: Low-energy internal cardioversion is a new electrical treatment for patients with persistent atrial fibrillation. This paper evaluates the efficacy and safety of low-energy internal cardioversion in patients with long-lasting atrial fibrillation refractory to external electrical cardioversion, and the clinical outcome of such patients. METHOD AND RESULTS: The study population consisted of 55 patients [32 male, mean age 65 +/- 10 years, 48 (87%) with underlying heart disease] with long-lasting (mean 18 +/- 34 months) atrial fibrillation in whom external cardioversion had failed to restore sinus rhythm. Two custom-made catheters were used: one positioned in the right atrium and one in the coronary sinus or the left pulmonary artery. A standard catheter was inserted into the right ventricular apex to provide R wave synchronization. Sinus rhythm was restored in 52 patients (95%) with a mean defibrillating energy of 6.9 +/- 2.6 J (320 +/- 60 V). No complications were observed. During follow-up (mean 18 +/- 9 months), 16 patients (31%) suffered early recurrence (< or = 1 week) of atrial fibrillation and 20 patients (38%) had late recurrence (> 1 week, mean 3.5 +/- 3.6 months) of atrial fibrillation. Six patients with a late recurrence again underwent cardioversion and five of these maintained sinus rhythm. Therefore, a total of 21/52 patients (40%) were in sinus rhythm at the end of follow-up. No clinical difference was found between patients with and without recurrences. CONCLUSIONS: Low-energy internal cardioversion is a useful means of restoring sinus rhythm in patients with long-lasting atrial fibrillation refractory to external electrical cardioversion. More than one-third of patients maintained sinus rhythm during long-term follow-up.     

Use of enalapril to facilitate sinus rhythm maintenance after external cardioversion of long-standing persistent atrial fibrillation. Results of a prospective and controlled study.

AIMS: This study aimed to assess whether enalapril could improve cardioversion outcome and facilitate sinus rhythm maintenance after conversion of chronic atrial fibrillation (AF). METHODS AND RESULTS: Patients with chronic AF for more than 3 months were assigned to receive either amiodarone (200mg orally 3 times a day; group I: n=75) or the same dosage of amiodarone plus enalapril (10mg twice a day; group II: n=70) 4 weeks before scheduled external cardioversion. The end-point was the time to first recurrence of AF. In 125 patients (86.2%), AF was converted to sinus rhythm. Group II had a trend to a trend to a lower rate of immediate recurrence of AF than group I did (4.3% vs 14.7%, P=0.067). Kaplan-Meier analysis demonstrated a higher probability of group II remaining in sinus rhythm at 4 weeks (84.3% vs 61.3%, P=0.002) and at the median follow-up period of 270 days (74.3% vs 57.3%, P=0.021) than in group II. CONCLUSIONS: The addition of enalapril to amiodarone decreased the rate of immediate and subacute arrhythmia recurrences and facilitated subsequent long-term maintenance of sinus rhythm after cardioversion of persistent AF.     

Predictors of success and effect of biphasic energy on electrical cardioversion in patients with persistent atrial fibrillation.

AIMS: We sought predictors of successful electrical cardioversion (ECV) and the effect of biphasic energy in patients considered candidates for rhythm control. METHODS AND RESULTS: The patients were drawn from a registry, which included prospectively 1355 consecutive patients with persistent atrial fibrillation who underwent ECV in 96 Spanish hospitals. Successful ECV was considered excluding patients with an early relapse. Factors related to successful cardioversion were evaluated using logistic regression with the patients segregated with respect to the use of monophasic or biphasic energy. Sinus rhythm was restored in 92% of the patients, of which, 5% had an early relapse. Thus, we considered that a successful ECV was achieved in 87% of patients. Body surface area was the only factor independently related to failure of the monophasic energy cardioversion (OR = 0.20; P = 0.001). No single factor was predictive of biphasic energy cardioversion failure. Biphasic energy was more effective in restoring sinus rhythm in patients with body surface area >2.05 m(2) (83% success in monophasic vs. 92% in biphasic; P = 0.02). CONCLUSION: Body surface area was the only factor related to the success of ECV, but only in patients treated with monophasic energy. Biphasic energy should be the technique-of-choice in patients with a large body surface area.     

The optimal technique for electrical cardioversion of atrial fibrillation

The optimal approach to electrical cardioversion of atrial fibrillation includes appropriate patient selection, anticoagulation, careful selection and monitoring of antiarrhythmic therapy, and proper electrical cardioversion technique. The optimal technique requires the use of metal electrodes, with one electrode of at least 8 cm in diameter placed in the anterior position, and the second of 12–13 cm diameter placed posteriorly just below the left scapulae, with generous amounts of the appropriate gel (such as Hewlett-Packard Redux Paste) as the electrode-skin interface and firm pressure to the paddle electrode with the patient in expiration. Thus the anterior-posterior chest diameter is decreased and less air between the electrodes is assured. The initial shock strength should be 200 J. The shock is synchronized with the electrocardiographic QRS complex. This report reviews the justification for these recommendations.     

Intermittent interatrial block after electrical cardioversion for atrial fibrillation

A 67-year-old woman with persistent atrial fibrillation presented for elective electrical cardioversion. The patient was cardioverted to normal sinus rhythm with a synchronized 150 joules (J) biphasic shock. Varying P-wave morphology suggesting intermittent interatrial block (IAB) was noted after the cardioversion on the rhythm strip. Three minutes later the patient developed early recurrence of atrial fibrillation and a second successful 150 J biphasic shock was delivered; IAB was still evident on a single lead II monitoring. However, the patient remained in sinus rhythm. The patient was discharged in normal sinus rhythm with electrocardiographic evidence of intermittent interatrial block. This case report examines the occurrence of IAB postcardioversion for atrial fibrillation and speculates on its prognostic significance.     

Maintenance of sinus rhythm after electrical cardioversion for recurrent atrial fibrillation following mitral valve surgery with or without associated radiofrequency ablation

Background

This study reports the outcomes of patients who underwent electrical cardioversion for atrial fibrillation recurrence following mitral valve surgery and associated radiofrequency ablation compared to those who did not undergo concomitant atrial fibrillation ablation.

Methods

The population consisted of 116 patients with persistent/long-standing persistent AF who underwent mitral valve surgery with (Group A, n = 54) or without (Group B, n = 62) associated radiofrequency ablation between January 2007 and January 2011 at three institutions and who subsequently underwent cardioversion for persistent atrial fibrillation within 12 months of their initial procedure.

Results

The mean follow-up duration was 30.7 ± 9.4 months. Of the 104 patients with acute restoration of SR 42 (40.3%) had AF recurrence. The average time to recurrence after cardioversion was 7.3 ± 4.2 days. Recurrence was significantly lower in patients undergoing ablation surgery (21.4%) than in those undergoing no ablation surgery (78.6%, p < 0.001). Non-performed ablation procedure (p < 0.001), time from surgery ≥ 88 days and left atrial dimensions ≥ 45.5 mm before cardioversion (both, p = 0.005) were multivariable predictors of atrial fibrillation recurrence. In Group B the use of amiodarone was inversely correlated with recurrence of AF (p < 0.001). This correlation was not significant (r = − 0.02, p = 0.85) in Group A.

Conclusions

Electrical cardioversion for recurrent AF showed better results and stable recovery of sinus rhythm in patients undergoing concomitant surgical ablation during mitral valve surgery. This might be attributable to substrate modification caused by surgical lesions. Amiodarone improved the ECV-success rate only in patients with no associate ablation. Further larger randomized studies are necessary to confirm our findings.     

Pre-treatment with Irbesartan attenuates left atrial stunning after electrical cardioversion of atrial fibrillation.

AIMS: Left atrial (LA) stunning, the transient impairment of LA function, is responsible for an increased thrombo-embolic risk after cardioversion of atrial fibrillation (AF). Angiotensin receptor blockers (ARBs) attenuate atrial remodelling in AF and could theoretically influence LA stunning. We studied the effect of Irbesartan on LA stunning. METHODS AND RESULTS: We prospectively assigned 50 patients from the outpatient clinic undergoing electrical cardioversion for AF with duration of >4 weeks, into two matched groups: 25 patients were treated with Irbesartan (228+/-93 mg/day) for at least 2 weeks prior to cardioversion (Irbesartan group); 25 patients did not receive ARBs (control group). The groups did not differ concerning age (64+/-13 vs. 63+/-13 years, respectively), AF duration (20+/-18 vs. 20+/-19 weeks), underlying disease, LA diameter (46+/-7 vs. 47+/-9 mm), left ventricular dimensions, and ejection fraction (47.7+/-11.6 vs. 49.7+/-14.5%). We assessed LA appendage emptying velocities (LAAEV) and LA spontaneous echo contrast (LASEC) by transoesophageal echocardiography before and after cardioversion and at 2 weeks, and the A-wave by transthoracic echocardiography after cardioversion, at 2 and at 4 weeks. LA stunning was significantly attenuated in the Irbesartan group. The reduction of LAAEV immediately after cardioversion was significantly less in the Irbesartan group (LAAEV reduction of 9+/-49% from 28+/-9 cm/s before cardioversion to 25+/-13 cm/s immediately afterwards) than in the control group (reduction of 48+/-20% from 34+/-15 cm/s before cardioversion to 16+/-6 cm/s afterwards) (P = 0.048). New or increased LASEC occurred in eight patients (32%) in the Irbesartan vs. 16 patients (64%) in the control group (P = 0.046). CONCLUSION: Irbesartan significantly attenuates LA stunning after electrical cardioversion of AF. Therefore, ARBs may represent an important pharmacological supplementation in patients being prepared for cardioversion.     

Maintenance of sinus rhythm with metoprolol CR initiated before cardioversion and repeated cardioversion of atrial fibrillation: a randomized double-blind placebo-controlled study.

AIMS: To assess the effect of metoprolol in combination with repeated cardioversion on maintenance of sinus rhythm (SR). METHODS AND RESULTS: Consecutive outpatients with persistent atrial fibrillation (AF) were randomized to treatment with metoprolol CR or placebo in a double-blind fashion. Study treatment was started at least one week before direct current (DC) cardioversion. Patients were followed once a week during the first 6 weeks after cardioversion. In case of relapse during this period, a second cardioversion was performed. Total treatment time was 6 months. A total of 168 patients were randomized to metoprolol (n = 83) or placebo (n = 85). The dose of study treatment at cardioversion was 169 +/- 47 mg in the metoprolol group and 180 +/- 40 mg in the placebo group (P = 0.12). In an intention-to-treat analysis, 46 patients (55%) in the metoprolol group and 34 patients (40%) in the placebo group (P = 0.04) had SR 1 week after cardioversion, and 38 patients (46%) in the metoprolol group compared with 22 patients (26%) in the placebo group had SR after 6 months (P < 0.01). CONCLUSION: A treatment strategy of metoprolol CR started before cardioversion in combination with prompt second cardioversion in case of early relapse (1-6 weeks) significantly increases the proportion of patients in SR during six months of follow-up.     

Transoesophageal low-energy cardioversion of atrial fibrillation. Results with the oesophageal-right atrial lead configuration.

BACKGROUND: Low energy internal cardioversion is a safe and effective procedure to restore sinus rhythm in patients with atrial fibrillation refractory to external cardioversion. However the procedure is invasive and fluoroscopy is mandatory.Aim of the study To assess the efficacy, safety and tolerability of a new simplified procedure of low energy internal cardioversion. METHODS: Twenty-five consecutive patients (19 males and 6 females) with persistent atrial fibrillation were submitted to low energy internal cardioversion using a step-up protocol (in steps of 50 V, starting from 300 V). A large surface area lead (cathode) was positioned in the oesophagus, 45 cm from the nasal orifice. A second large surface area lead (anode) was positioned in the right atrium. A quadripolar lead was positioned at the right ventricular apex to achieve ventricular synchronization and back-up pacing. Oesophageal endoscopy was performed within 24 h of the end of the procedure and repeated after 48 h, if injury to the oesophageal mucosa had occurred. RESULTS: Sinus rhythm was restored in 23 patients (92%) with a mean delivered energy of 15.74 J (range 5-27) and a mean impedance of 48 Omega. In two patients, endoscopy revealed that small burns had occurred in the oesophageal mucosa. Such lesions spontaneously healed after 48 h. CONCLUSIONS: This new technique of performing low energy internal cardioversion is effective and safe and avoids the positioning of a lead in the coronary sinus or in the left pulmonary artery, thereby simplifying the procedure.     

Impact of biphasic electrical cardioversion of atrial fibrillation on early recurrent atrial fibrillation and shock efficacy

INTRODUCTION: Early recurrent atrial fibrillation (ERAF) after external cardioversion of atrial fibrillation (AF) occurs in 12% to 26% of patients. Whether biphasic cardioversion has an impact on the incidence of ERAF after cardioversion of AF is unclear. METHODS AND RESULTS: Consecutive patients (n = 216, mean age 66 years, 71% male, 88% with structural cardiovascular disease or hypertension) underwent cardioversion with a biphasic (Bi) or monophasic (Mo) shock waveform in randomized fashion. Energies used were 120-150-200-200 Ws (Bi) or 200-300-360-360 Ws (Mo). The two study groups (Bi vs Mo) did not differ with regard to age, sex, body mass index, underlying cardiovascular disease, left atrial diameter, left ventricular ejection fraction, duration of AF fibrillation, and antiarrhythmic drug therapy. Mean delivered energy was significantly lower in the Bi group (Bi: 186 +/- 143 Ws vs Mo: 324 +/- 227 Ws; P < 0.001). Overall incidence of ERAF (AF relapse within 1 minute after successful cardioversion) was 8.9% and showed no difference between the two groups (Bi: 8.1% vs Mo: 9.7%, P = NS). Cardioversion was successful in 95.4% of patients. The success rate was comparable in both groups (Bi: 94.3% vs Mo 96.8%; P = NS). First shock efficacy did not differ between Bi and Mo (76.4% vs 67.7%; P = NS). Mean number of shocks were 1.4 shocks per patient in both groups. CONCLUSION: Biphasic cardioversion allows comparable success rates with significantly lower energies. However, the incidence of ERAF is not influenced by biphasic cardioversion. With the energies used, biphasic and monophasic shock waveforms are comparable with regard to first shock and cumulative shock efficacy.