Efficacy of internal cardioversion for chronic atrial fibrillation in patients with and without left ventricular dysfunction

Internal cardioversion can restore sinus rhythm with energies below 6-10 J, often without anaesthesia/sedation. We investigated its safety and short-/medium-term efficacy in patients with persistent atrial fibrillation (AF) with left ventricular dysfunction (defined as ejection fraction < or = 40%). Among 34 patients with persistent AF who agreed to receive internal cardioversion, 16 had left ventricular dysfunction and 18 did not (the groups were similar as regards age, duration of AF and pretreatment with amiodarone). Internal CV was performed delivering 3.0/3.0-ms biphasic shocks between coil catheters using a step-up protocol. Sinus rhythm was always restored. General anaesthesia (administered only when discomfort was not tolerated) was required only in 2 of the 16 (12.5%) patients with left ventricular dysfunction. The defibrillation threshold was similar in patients with and without left ventricular dysfunction (10.2+/-6.9 vs. 8.4+/-4.9 J; p=0.37). Short-term (within 72 h) AF recurrence rates in the presence and absence of left ventricular dysfunction were 19% (3/16) and 6% (1/18), respectively (p=0.51). After cardioversion, all patients received antiarrhythmic drugs (mostly amiodarone in patients with left ventricular dysfunction and class IC agents in the remainder). With mean follow-up periods of about 220 days, AF recurrence rates among patients with and without left ventricular dysfunction were 50% (8/16) and 28% (5/18), respectively (p=0.328). We conclude that even in patients with left ventricular dysfunction, internal CV is safe and effective, minimizing risks from anaesthesia. Although these patients may have a higher risk of short- or medium-term AF recurrence, 6-month maintenance of sinus rhythm is possible in about 50% of cases.     

P wave dispersion and short-term vs. late atrial fibrillation recurrences after cardioversion

BACKGROUND: P wave dispersion has been previously suggested as a potential tool for predicting the risk of recurrence of atrial fibrillation after electrical cardioversion. We investigated whether different P wave dispersion values are associated with recurrence of atrial fibrillation in the short (< or =1 month after cardioversion) and longer term. METHODS: In 37 patients with long-lasting persistent atrial fibrillation (mean duration 21 +/- 36 months) with (n = 19) or without (n = 18) amiodarone pretreatment as antiarrhythmic prophylaxis, maximum and minimum P wave duration and P wave dispersion were measured 1 min after internal cardioversion. RESULTS: P wave dispersion was lower in patients with amiodarone pretreatment (28.3 +/- 9.5 vs. 21.9 +/- 7.3 ms, P = 0.029). The subgroups of patients with recurrence of atrial fibrillation at 1 month or in the long-term did not differ from the rest of the study sample regarding age, sex, atrial fibrillation duration, left atrial dimensions or ejection fraction. P wave dispersion was significantly higher in patients with short-term atrial fibrillation recurrence (< or = 1 month) than in the rest of the population. Furthermore, P wave dispersion values >25 ms were associated with a higher short-term relapse rate. No significant relation was present in the long-term. CONCLUSIONS: Our results suggest that P wave dispersion analysis immediately after internal cardioversion may help predict short-term recurrences of atrial fibrillation. These findings may be related to different mechanisms and predisposing factors for short-term and late recurrences. The long-term predictive value of serial evaluations of P wave dispersion during follow-up deserves investigation.     

Ibutilide in persistent atrial fibrillation refractory to conventional cardioversion methods

BACKGROUND: Electrical cardioversion of atrial fibrillation seems to be enhanced by pretreatment with ibutilide, but only few is known about the effects of ibutilide in atrial fibrillation which failed to convert with class III antiarrhythmic agents and electrical cardioversion. The objectives of this study were to evaluate the efficacy and safety of ibutilide administration in patients with persistent atrial fibrillation refractory to long-term therapy with class III antiarrhythmic drugs and transthoracic cardioversion. METHODS: Prospective study in 22 patients (16 men and 6 women, mean age 63+/-9 years) with structural heart disease and persistent atrial fibrillation for a mean duration of 39+/-50 (range 1-145) months. All patients had failed to convert to sinus rhythm after transthoracic cardioversion while on treatment with class III antiarrhythmic drugs (amiodarone in 82%, sotalol in 18%). One milligram of ibutilide was administered in all patients and electrical cardioversion was performed again, if necessary. RESULTS: The total conversion rate to sinus rhythm was 95% (21 of 22 patients). Two patients (9%) were successfully converted after ibutilide alone and 19 patients (86%) when transthoracic cardioversion was repeated after ibutilide. The QTc intervals increased from 451+/-28 to 491+/-49 ms (p<0.001) after ibutilide. No adverse effects occurred. The rate of freedom from atrial fibrillation after 1 month of follow-up was 64%. CONCLUSIONS: The efficacy of concomitant use of ibutilide infusion and, if necessary, repeated transthoracic cardioversion for restoration of sinus rhythm in long-term persistent atrial fibrillation and previously failed antiarrhythmic and electrical cardioversion was 95%. There were no adverse effects associated with ibutilde administration. Our results suggest that this combined strategy may be safe and successful in patients with atrial fibrillation resistant to conventional cardioversion methods and may be an alternative to internal cardioversion.     

The effect of oral magnesium, alone or as an adjuvant to sotalol, after cardioversion in patients with persistent atrial fibrillation.

AIMS: To determine whether magnesium given orally decreases the recurrence rate of atrial fibrillation after elective direct current cardioversion of persistent atrial fibrillation. METHODS AND RESULTS: Consecutive outpatients were randomized to treatment with oral magnesium (10.3 mmol) or placebo twice daily in a double-blind fashion. Two groups were studied; magnesium study: 170 patients with atrial fibrillation persistent for >1 month, scheduled for their first direct current cardioversion. No concomitant antiarrhythmic drugs of class I or III were allowed. Sotalol and magnesium study: 131 patients with recurrence of persistent atrial fibrillation after previous direct current cardioversion, or a history of paroxysmal atrial fibrillation, treated with sotalol. Patients were followed until recurrence of atrial fibrillation or for at least 6 months. Magnesium study: at cardioversion 67 of 85 (79%) in the placebo group and 64 of 85 (75%) in the magnesium group had converted to sinus rhythm. At the end of the study, with a follow-up of 6 to 42 months, 15% of patients in the placebo group and 19% of patients in the magnesium group remained in sinus rhythm (Log rank test: P=0.37). Sotalol and magnesium study: pharmacological conversion to sinus rhythm, after oral treatment, was achieved in 34 of 131 (26%) patients. Sinus rhythm, with or without cardioversion, was restored in 89% and 85% of the patients in the placebo and magnesium groups, respectively. At the end of the study, with a follow-up of 6 to 42 months, 37% of patients in the placebo group and 30% of patients in the magnesium group remained in sinus rhythm (Log rank test: P=0.64). CONCLUSION: In patients with persistent atrial fibrillation, oral treatment with magnesium alone or as an adjuvant to sotalol, does not influence the recurrence rate of atrial fibrillation after elective cardioversion.     

Oral amiodarone increases the efficacy of direct-current cardioversion in restoration of sinus rhythm in patients with chronic atrial fibrillation.

AIMS: Direct current cardioversion of persistent atrial fibrillation is one of the most widely used and effective treatments for the restoration of sinus rhythm, but may be hampered by a low success rate and a high percentage of early recurrence. Pre-treatment with amiodarone or a glucose-insulin-potassium solution could improve the efficacy of electrical cardioversion by reversing the partially depolarized diastolic potential of the subsidiary pacemakers in atrial fibrillation. In a controlled randomized study, we assessed the effectiveness of electrical cardioversion in patients with persistent atrial fibrillation after pre-treatment with amiodarone or potassium infusion and the efficacy of amiodarone in maintaining sinus rhythm after electrical cardioversion. METHODS AND RESULTS: Ninety-two patients with persistent atrial fibrillation (>2 weeks duration) were prospectively randomized into three matched groups: A (n=31, oral amiodarone 400 mg. day(-1)1 month before and 200 mg. day(-1)2 months after cardioversion), B (n=31, 180 mg. day(-1)oral diltiazem 1 month before and 2 months after cardioversion and 80 mmol potassium, 50 UI insulin in 500 ml 30% glucose solution 24 h before cardioversion) and C (n=30, control patients, 180 mg. day(-1)oral diltiazem 1 month before and 2 months after cardioversion). Before cardioversion all patients were under 4 weeks effective oral anticoagulant therapy (warfarin). Before electrical cardioversion, the rate of spontaneous conversion to sinus rhythm was higher in group A (25%) than groups B (6%) or C (3%) (P<0.005). Electrical cardioversion was more successful in group A (88%) than groups B (56%) or C (65%) (P<0.05), while the electrical thresholds for effective cardioversion were lower in group B than the other groups (P<0.05). Twenty-four hours after cardioversion, the early recurrence of atrial fibrillation was similar in the three groups (P=ns), while at 2 months the recurrence rate was lower in group A (32%) than groups B (56%) or C (52%) (P<0.01). CONCLUSION: Pre-treatment with low-dose oral amiodarone, compared with oral diltiazem or glucose-insulin-potassium treatments, induces a significantly high percentage of instances of spontaneous conversion, increases electrical cardioversion efficacy and reduces atrial fibrillation recurrence.     

Amiodarone in restoration and maintenance of sinus rhythm in patients with chronic atrial fibrillation after unsuccessful direct-current cardioversion

Background: When direct-current (DC) cardioversion is used, sinus rhythm can be restored, at least temporarily, in 80–90% of patients with atrial fibrillation. However, there is a small but significant group of patients with chronic atrial fibrillation in whom DC cardioversion has failed to restore sinus rhythm. The value of antiarrhythmic drug pretreatment before DC cardioversion is still controversial. Hypothesis: The aim of our study was to assess (1) the effecti veness of repeat DC cardioversion in patients with chronic atrial fibrillation after pretreatment with amiodarone, and (2) the efficacy of amiodarone in maintaining sinus rhythm after repeat cardioversion. Methods: Forty-nine patients with chronic atrial fibrillation after ineffective DC cardioversion were included in the study. Repeat DC cardioversion was performed after loading with oral amiodarone, 10–15 mg/kg body weight/day for a period necessary to achieve the cumulative dose of over 6.0 g. Results: Spontaneous conversion to sinus rhythm during amiodarone pretreatment was achieved in 9 of 49 patients (18%). Direct-current cardioversion was performed in 39 patients and sinus rhythm was achieved in 23 of these patients (59%). Mean heart rate decreased from 95 beats/min before to 68 beats/min after DC cardioversion (p<0.001). Systolic blood pressure significantly (p<0.05) decreased from 126 ± 23 to 108 ± 25 mmHg. Complications occurring in four patients just after electroconversion were well tolerated and of short duration. After 12 months, 52% of patients maintained sinus rhythm on low dose (200 mg/day) amiodarone therapy. Conclusion: Pretreatment with amiodarone and repeat DC cardioversion allows for restoration of sinus rhythm in about 65% of patients with chronic atrial fibrillation after first ineffective DC cardioversion. Direct-current cardioversion can be performed safely with the use of standard precautions in patients who are receiving amiodarone. At 12 months' follow-up, more than 50% of patients maintain sinus rhythm on low-dose amiodarone after successful repeat cardioversion.     

Comparative effects of carvedilol and amiodarone on conversion and recurrence rates of persistent atrial fibrillation

Pretreatment with antiarrhythmic agents could improve cardioversion and recurrence rates in patients with persistent atrial fibrillation. In a prospective controlled trial, 145 patients were randomly assigned to treatment with carvedilol, amiodarone, or placebo for 4 weeks before electrical cardioversion. Although the 2 drugs had similar effects on cardioversion rates, amiodarone was superior in terms of sinus rhythm maintenance after conversion.     

Success of serial external electrical cardioversion of persistent atrial fibrillation in maintaining sinus rhythm; a randomized study.

AIMS: The aim of this prospective, randomized study was to determine the efficacy of a serial external electrical cardioversion strategy in maintaining sinus rhythm after 12 months in patients with recurrent persistent atrial fibrillation. METHODS AND RESULTS: Ninety patients with persistent atrial fibrillation lasting more than 72 h but less than 1 year were randomized in a one to one fashion to repetition of up to two electrical cardioversions in the event of relapse of atrial fibrillation detected within 1 month of the previous electrical cardioversion (Group AGG), or to non-treatment of atrial fibrillation relapse (Group CTL). ECGs were scheduled at 6 h, 7 days, and 1 month. Clinical examination and ECGs were repeated during the 6-month and 12-month follow-up examinations. Echocardiography was repeated during the 6-month follow-up examination. Clinical and echocardiographic characteristics were similar in the two groups. All patients were treated with antiarrhythmic drugs before electrical cardioversion and throughout follow-up. After 12 months, sinus rhythm was maintained in 53% of Group AGG patients and in 29% of Group CTL patients (P<0.03). After 6 months, left ventricular ejection fraction had recovered significantly only in Group AGG (56.8 +/- 9.0% at enrollment vs 60.4 +/- 9.4% at 6 months,P <0.001). CONCLUSION: These results demonstrate that an aggressive policy towards persistent atrial fibrillation by means of repetition of electrical cardioversion after early atrial fibrillation recurrence is useful in maintaining sinus rhythm after 12 months.     

血管紧张素Ⅱ受体拮抗剂、胺碘酮联用对预防心房颤动的影响

目的观察厄贝沙坦联用胺碘酮在持续性心房颤动转复后维持窦性心律的作用及对左心房功能的影响。方法98例持续性心房颤动(持续超过7d)患者,药物或电复律后随机分为两组,Ⅰ组50例给予胺碘酮0.2g,1次/d;Ⅱ组48例给予厄贝沙坦150mg,1次/d,胺碘酮0.2g,1次/d;两组均连服6个月。分别于治疗后第1周、2周、1个月、2个月、4个月及6个月复查心电图或动态心电图,观察心房颤动复发情况;复律后次日及6个月后做超声心动图(UCG)检查,观察左心房功能变化。结果共87例完成治疗。随访6个月,心房颤动复发Ⅰ组为34.9%(15/43),Ⅱ组为13.6%(6/44),两组比较差异有统计学意义(P<0.05),Ⅱ组复律后次日及治疗6个月后,超声测量左心房内径由(42±12)mm缩小为(34±11)mm,治疗前与治疗6个月后比较差异有统计学意义(P<0.01),而Ⅰ组上述指标比较差异无统计学意义(P>0.05)。结论厄贝沙坦联用胺碘酮在持续性心房颤动转复后维持窦性心律,较单用胺碘酮更有效,长期服用厄贝沙坦可逆转左心房扩大,降低左心房压,有利于消除心房颤动复发的基础。     

心房颤动电复律与胺碘酮节律控制的效果——附53例临床观察

目的：观察电复律＋胺碘酮维持治疗对持续性心房颤动（房颤）节律控制的效果及安全性。方法：回顾分析2007年8月至2010年12月在我院行心脏电复律＋胺碘酮维持治疗的53例持续性房颤患者的资料,对复律≥2年的24例患者进行随访,其中维持窦性心律1.5年者16例（复律组）,房颤复发者8例（复发组）。结果：53例有50例达到复律早期成功,早期成功率为94.3%,与电复律前比较,电复律后患者的总心室率[（109777±6757）次/min比（81083±5036）次/min]、平均心率[（81±8）次/min比（62±6）次/min]、最快心室率[（145±13）次/min比（123±11）次/min]、最慢心室率[（67±7）次/min比（45±6）次/min]明显减低（P〈0.05）;与复律组比较,复发组的房颤持续时间[（4.36±1.47）月比（8.7±2.15）月]、左房内径[（35.85±2.07）mm比（43.15±1.95）mm]、年龄[（54.3±11.7）岁比（72.1±8.3）岁]均明显增大（P〈0.01～〈0.001）。所有病人无明显副作用。结论：电复律联合小剂量胺碘酮维持治疗对大部分持续性房颤患者有效、安全、简便,应该推广。     

Factors predicting success rate and recurrence of atrial fibrillation after first electrical cardioversion in patients with persistent atrial fibrillation

BACKGROUND: The recurrence rate of atrial fibrillation (AF) after elective cardioversion is high. HYPOTHESIS: The study aimed to identify clinical predictors for successful electrical cardioversion and maintenance of sinus rhythm after a first electrical cardioversion in patients with persistent AF without concomitant antiarrhythmic drugs of class I and III. METHODS: Consecutive outpatients (n = 166) with persistent AF for > 1 month, scheduled for elective cardioversion, were prospectively included in the study. A clinical investigation, echocardiographic assay, and Holter electrocardiogram (ECG) before and ECG 4 weeks after cardioversion, were performed in all patients. RESULTS: The mean age of the patients was 68 years (range 45-83) and duration of AF was 5 (1-48) months. Sinus rhythm was established in 124 (75%) patients. In multivariate analysis, only duration of AF < 6 months (p < 0.04, odds ratio [OR] 2.2, 95% confidence interval [CI] 1.1 to 4.7) and patients weight (p < 0.03, OR 2.3, 95% CI 1.1 to 4.8 for weight < 80 kg) were identified as independent predictors of successful cardioversion. At 4 weeks after cardioversion, only 46 (37%) of 124 patients maintained sinus rhythm. Independent factors for maintenance of sinus rhythm, in multivariate analysis, were AF <3 months (p < 0.04, OR 2.5, 95% CI 1.1 to 5.6), treatment with beta blockers (p < 0.00001, OR 7.0, 95% CI 3.0 to 16.3) or verapamil/diltiazem (p < 0.04, OR 3.6, 95% CI 1.1 to 12.1), and right atrial dimension < 37 mm (p < 0.02, OR 5.9, 95% CI 1.4 to 25.4). CONCLUSIONS: In patients with persistent AF, the patient's weight and the duration of AF are independent predictors for a successful cardioversion. Short duration of AF, treatment with beta blockers or verapamil/diltiazem, and right atrial area/dimension are independent predictors for maintenance of sinus rhythm.     

Echocardiographic changes and predictors of arrhythmia recurrence after long-term use of the atrial defibrillator

BACKGROUND: The patient-activated atrial defibrillator allows patients to cardiovert themselves from atrial fibrillation soon after the onset of symptoms. The long-term effects of early cardioversion from persistent atrial fibrillation on left ventricular performance and left atrial size are unknown. METHODS: Eighteen patients, mean age 63.4, 83% male, had the Jewel((R)) AF atrial defibrillator implanted for persistent atrial fibrillation only. Transthoracic echocardiography was performed 3-monthly following implant. Parasternal long axis measurements were taken using conventional M-mode techniques. RESULTS: Over follow-up of 28.0+/-9 months, 377 episodes of persistent atrial fibrillation were terminated by patient-activated cardioversion (median 15 per patient). Echocardiographic measurements at implant were; left atrium 44+/-6 mm, left ventricular end-diastolic diameter 49+/-7 mm, left ventricular end-systolic diameter 34+/-7 mm, fractional shortening 33+/-10% and ejection fraction 65+/-17%. After 1 year there had been a significant decrease in mean left atrial size to 41+/-6 mm (P=0.02) and an increase in mean ejection fraction to 73+/-8% (P=0.04). At long-term follow-up however, all parameters reverted to pre-implant levels. Baseline echocardiographic variables did not predict which patients would demonstrate serial increases in sinus rhythm duration between shocks during long-term follow-up. Patients on antiarrhythmic drug therapy however were more likely to demonstrate "sinus rhythm begetting sinus rhythm". CONCLUSIONS: Use of the atrial defibrillator for spontaneous persistent atrial fibrillation is associated with a medium-term (1 year) reduction in left atrial size and an increase in ejection fraction. These changes were not maintained in the long-term. Synergistic therapy with antiarrhythmic drugs may prolong periods of sinus rhythm between arrhythmia recurrences.     

Usefulness of plasma B-type natriuretic peptide in predicting recurrence of atrial fibrillation one year after external cardioversion

After successful external cardioversion, the rate of recurrence of atrial fibrillation remains high. The hypothesis that plasma B-type natriuretic peptide could predict the recurrence of atrial fibrillation at 1 year was tested. Plasma B-type natriuretic peptide was measured in 66 consecutive asymptomatic patients who underwent external cardioversion for atrial fibrillation. Twelve-lead electrocardiograms were obtained at 1 year. Sinus rhythm was maintained in 55% of patients. The independent predictors of the recurrence of atrial fibrillation at 1 year were a history of atrial fibrillation, plasma B-type natriuretic peptide, and the energy delivered for conversion. In patients without symptoms of heart failure, plasma B-type natriuretic peptide is an independent predictor of the recurrence of atrial fibrillation.     

The value of transesophageal echocardiography for determination of tactics of cardioversion of atrial fibrillation

Transesophageal echocardiography was carried out in 110 patients before cardioversion of nonvalvular atrial fibrillation which duration exceeded 2 days. Twenty thrombi were found in 18 patients (16.4%). Anticoagulant phenindione was given to these patients for 3 weeks. Patients without thrombus received intravenously amiodarone followed with procainamide. Sinus rhythm was restored in 39.3% of these cases. In 5.5% of patients atrial fibrillation terminated spontaneously. Control transesophageal echocardiography showed that after 3 weeks there remained 11 atrial thrombi but all of them lost motility. Electrical cardioversion was successful in 90.7% of patients receiving short term and in 80% of patients receiving 3-week anticoagulant therapy (p>0.05). All patients received phenindione for 4 weeks after cardioversion. There were no thromboembolic or hemorrhagic complications. Ability of transesophageal echocardiography to detect atrial thrombi allows to carry out early cardioversion and to identify patients with high risk of embolism.     

Prediction of atrial fibrillation recurrence after cardioversion by P wave signal-averaged electrocardiography.

The purpose of this report was to determine prospectively whether P wave signal-averaged electrocardiography (ECG) is useful for the prediction of recurrences of atrial fibrillation after cardioversion. The P wave signal-averaged ECG was recorded in 73 patients after successful cardioversion. Duration of the filtered P wave and the root mean square voltages for the last 20 ms of the P wave were calculated. In addition to signal-averaged ECG P wave analysis, all patients were evaluated by echocardiography. During 6 months follow-up period recurrence of atrial fibrillation was observed in 31 (42.5%) patients and in 42 (57.5%) patients sinus rhythm was maintained. There was no difference in gender, age, presence of organic heart disease, left atrial diameter, left ventricular ejection fraction, use of antiarrhythmic drug, and duration of atrial fibrillation (P>0.05). The filtered P-wave duration was longer and the root mean square voltages for the last 20 ms of the P wave was lower in patients with recurrence of atrial fibrillation than in patients who maintained sinus rhythm (138.3+/-12.5 ms vs. 112.4+/-11.8 ms, P = 0.001; 1.9+/-0.7 microV vs. 2.5+/-0.6 microV, P = 0.001). A filtered P-wave duration > or =128 ms associated with a root mean square voltage for the last 20 ms of the P wave < or =2.1 microV had a sensitivity of 70% and specificity of 76% for the detection of patients with recurrence of atrial fibrillation after successful cardioversion of atrial fibrillation. We found that the likelihood of recurrence of atrial fibrillation after cardioversion was increased 4.31-fold (95% confidence interval 2.08-9.83) if these parameters were used. These results suggest that P wave signal-averaged ECG could be useful to identify patients at risk for recurrence of atrial fibrillation after cardioversion.     

High maintenance rate of sinus rhythm after cardioversion in post-thyrotoxic chronic atrial fibrillation

We performed rhythm conversion on 33 euthyroid patients with post-thyrotoxic atrial fibrillation who do not revert spontaneously to sinus rhythm from atrial fibrillation. The duration of atrial fibrillation ranged from 9 to 59 months (mean 25 +/- 14). The protocol of rhythm conversion was to first attempt pharmacological conversion with disopyramide and then to perform electrical cardioversion on the non-converters. Of 33 patients, 25 were converted to sinus rhythm (6 by disopyramide and 19 by electrical cardioversion), resulting in 8 non-converters. However, it was later discovered that cardioversion had been applied to 4 of the 8 non-converters when these patients had had a recurrence of thyrotoxicosis. These 4 patients were subjected to a second electrical cardioversion after attaining the euthyroid state. Sinus rhythm was restored in all 4 patients, giving a cardioversion rate of 88%. The sinus rhythm was maintained in 25 of the total 29 converters (86%) at the time of follow-up (10-68 months, mean 35 +/- 19 months). Our studies suggest that cardioversion should be encouraged for thyrotoxic atrial fibrillation, even if the duration of atrial fibrillation is long-standing, since there is excellent maintenance of sinus rhythm and even delayed application of cardioversion may improve its success rate.     

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.     

Control of rate versus rhythm in rheumatic atrial fibrillation: a randomized study

BACKGROUND: Patients with rheumatic heart disease and atrial fibrillation incur significant morbidity and mortality. It is not known which approach, rate control or maintenance of sinus rhythm might be most appropriate. The present study was undertaken to compare the strategy of ventricular rate control versus maintenance of sinus rhythm in rheumatic atrial fibrillation, and to evaluate the role of amiodarone in this patient population. METHODS AND RESULTS: We prospectively studied 144 patients with chronic rheumatic atrial fibrillation in a double-blind protocol-rhythm control (group I: 48 patients each with amiodarone -group Ia; and placebo -group Ib) and compared the effects with the ventricular rate control (group II) by diltiazem (n=48, open-label). Direct current cardioversion was attempted in group I. The mean age of the study population was 38.6+/-10.3 years, left atrial size was 4.7+/-0.6 cm, atrial fibrillation duration was 6.1+/-5.4 years, and 72.9% patients had undergone valvular interventions. At 1 year, 45 patients with sinus rhythm in group I compared to 48 patients in group II demonstrated significant increase in exercise to sinus rhythm time, had improvement in functional class and quality of life score. There was no difference in hospitalization rates, systemic bleeds or incidence of thromboembolism. Five patients died in group II but none in group I (p=0.02). In group I, 73/87 (83.9%) patients converted, and 45/86 (52.3%) patients maintained sinus rhythm at 1 year. Conversion rates were 38/43 (88.4%) with amiodarone versus 34/44 (77.3%) with placebo (p=0.49): corresponding rate for maintaining sinus rhythm was 29/42 (69.1%) versus 16/44 (36.4%), p=0.008 respectively. CONCLUSIONS: Maintenance of sinus rhythm appeared to be superior to ventricular rate control in patients with rheumatic atrial fibrillation in terms of an effect on mortality and morbidity. Sinus rhythm could be restored in the majority and amiodarone was superior to placebo in this regard.     

Comparison of intravenously administered dofetilide versus amiodarone in the acute termination of atrial fibrillation and flutter. A multicentre, randomized, double-blind, placebo-controlled study.

AIMS: This study compared the efficacy and safety of intravenous dofetilide with amiodarone and placebo in converting atrial fibrillation or flutter to sinus rhythm. METHODS AND RESULTS: One hundred and fifty patients with atrial fibrillation or flutter (duration range 2 h-6 months) were given 15-min intravenous infusions of 8 microg. kg(-1)of dofetilide (n=48), 5 mg. kg(-1)of amiodarone (n=50), or placebo (n=52) and monitored continuously for 3 h. Sinus rhythm was restored in 35%, 4%, and 4% of patients, respectively (P<0.001, dofetilide vs placebo;P=ns, amiodarone versus placebo). Dofetilide was more effective in atrial flutter than in atrial fibrillation (cardioversion rates 75% and 22%, respectively;P=0.004). The mean time to conversion with dofetilide was 55+/-15 min. Dofetilide prolonged the QTc interval (+16% at 20 min). Amiodarone substantially decreased the ventricular rate in non-converters (-18 beats. min(-1)at 30 min). Two patients given dofetilide (4%) had non-sustained ventricular tachycardias, and four (8%) had torsade de pointes, in one case requiring electrical cardioversion. CONCLUSION: Intravenous dofetilide is significantly more effective than amiodarone or placebo in restoring sinus rhythm in patients with atrial fibrillation or flutter. However, when infused intravenously at this dose and rate, dofetilide causes a significant incidence of torsade de pointes.     

Early cardioversion of atrial fibrillation facilitated by transesophageal echocardiography: short-term safety and impact on maintenance of sinus rhythm at 1 year

BACKGROUND: For patients presenting with atrial fibrillation of only a few weeks duration, the use of transesophageal echocardiography offers the opportunity to markedly abbreviate the duration of atrial fibrillation before cardioversion. We sought to determine if the shorter duration of atrial fibrillation allowed by a transesophageal echocardiography strategy had an impact on the recurrence of atrial fibrillation and prevalence of sinus rhythm during the first year following cardioversion.

METHODS: Transesophageal echocardiography was attempted in 539 patients (292 men, 247 women; 71.6 ± 13.0 years.) with atrial fibrillation ≥2 days (66.1% <3 weeks) or of unknown duration before elective cardioversion of atrial fibrillation. Therapeutic anticoagulation at the time of transesophageal echocardiography was present in 94.6% of patients, and 73.4% of subjects were discharged on warfarin.

RESULTS: Atrial thrombi were identified in 70 (13.1%) patients. Successful cardioversion in 413 patients without evidence of atrial thrombi was associated with clinical thromboembolism in 1 patient (0.24%, 95% confidence interval: 0.0–0.8%). In patients with atrial fibrillation <3 weeks at the time of cardioversion (a duration incompatible with conventional therapy of 3 to 4 weeks of warfarin before cardioversion), the 1-year atrial fibrillation recurrence rate was lower (41.1% vs. 57.9%, P <0.01), and the prevalence of sinus rhythm at 1 year was increased (65.8% vs. 51.3%, P <0.03). No other clinical or echocardiographic index was associated with recurrence of atrial fibrillation or sinus rhythm at 1 year.

CONCLUSIONS: Early cardioversion facilitated by transesophageal echocardiography has a favorable safety profile and provides the associated benefit of reduced recurrence of atrial fibrillation for patients in whom the duration of atrial fibrillation is <3 weeks.