Direct conversion of atrial flutter to sinus rhythm with low-output,short-duration transesophageal atrial pacing

Background and hypothesis: Transesophageal atrial pacing (TAP) is useful for terminating paroxysmal non-selfterminating atrial flutter (RAF); however, high output pacing of long stimulus duration causes severe symptoms such as chest pain. The objective of this study was to investigate the effect of low-output, short-duration TAP on the conversion of PAF. Methods: We applied low-output (within 15 mA with a pulse duration of 10 ms), short-duration (within 4 s) TAP in 31 patients (50±19 years) with PAF. Transesophageal pacing was delivered with 10 pulses of burst pacing at intervals that were 20 ms shorter than those of the flutter wave length. When the conversion was unsuccessful, we delivered 20 pulses of burst pacing. Results: Sixteen patients (52%) were converted directly to sinus rhythm and 12 (38%) to atrial fibrillation. Transesophageal pacing was ineffective in 3 (10%) patients. The duration of atrial flutter, maximum flutter wave amplitude, effective pacing intervals, underlying heart diseases, and cardiac function were not different between patients who had direct conversion to sinus rhythm and those converted to atrial fibrillation. The patients who had direct conversion to sinus rhythm had longer flutter wave cycle lengths than those converted to atrial fibrillation (248 vs. 221 ms, p<0.005). No patient had complications and complained of any symptoms. Conclusion: Low-output, short-duration TAP was useful to convert PAF directly to sinus rhythm without side effects.     

Predictors of conversion to sinus rhythm using ibutilide for atrial fibrillation or flutter

To determine what factors can predict conversion to sinus rhythm, we retrospectively studied 201 consecutive patients who received ibutilide for treatment of atrial fibrillation or flutter. On multivariate analysis, the following factors were significantly associated with conversion: recent onset of arrhythmia, an underlying atrial flutter rhythm, lack of a history of congestive heart failure, and lack of concomitant digoxin therapy.     

Fibrillation and atrial flutter. Immediate control and conversion to sinus rhythm with intravenous propafenone

The safety and efficacy of intravenous Propafenone, in the treatment of atrial fibrillation (a.f.) or flutter (A.F.) of recent onset (15 days), were assessed. Propafenone (2 mg/kg) was administered to 36 consecutive patients (mean age 60.8 years), 28 with a.f. and 8 with A.F. Nineteen patients (52.7%) reverted to sinus rhythm within 85 min (mean 27.2 min): 17 of 28 (60.7%) with a.f. and 2 of 8 (25%) with A.F. The efficacy of the drug was significantly influenced by the time elapsed from the onset of the arrhythmia: 14/21 (66.6%) patients with the arrhythmia lasting less then 48 hours and only 5/15 (33.3%) of those with the arrhythmia lasting more than 48 hours or of unknown onset, were converted (p less than 0.05). 18 patients underwent echocardiographic control: mean left atrial dimensions were 41.4 +/- 11.4 mm in converters and 47.4 +/- 11.2 mm in non converters (p = NS). Mean QRS lengthening observed was 16% (from 89 +/- 35.1 to 103.5 +/- 48.8 msec) (p = NS); QTc interval increased from 390 +/- 64.3 to 403 +/- 36.2 msec (p = NS). Arterial blood pressure showed significant changes only in two patients in whom a serious hypotension developed, needing infusion of adrenergic drugs. Non converters showed a reduction of the ventricular rate from 141.8 +/- 29.4/min to 101.8 +/- 18/min (p less than 0.01) meanwhile the shortest RR interval increased from 359.5 +/- 60.8 to 450 +/- 81.5 msec (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of procainamide with rapid atrial pacing for successful conversion of atrial flutter to sinus rhythm

Rapid atrial pacing is a useful technique and often the therapy of choice to terminate atrial flutter in patients. However, interruption of atrial flutter by rapid atrial pacing may not always produce sinus rhythm, but rather may result in atrial fibrillation. Twelve patients with spontaneous atrial flutter that had been present for greater than 24 h were studied to assess the efficacy of atrial pacing, alone and in combination with procainamide, to convert atrial flutter to normal sinus rhythm. Rapid atrial pacing for greater than or equal to 15 s from selected atrial sites at selected pacing rates were performed during atrial flutter. The initial pacing rate was always at a cycle length 10 ms shorter than the atrial flutter cycle length. If atrial flutter persisted after cessation of pacing, it was repeated at progressively shorter cycle lengths until either a rate of 400 beats/min was achieved or atrial fibrillation was induced. In two patients, atrial flutter was converted to sinus rhythm with pacing alone. Three patients developed sustained atrial fibrillation as a result of the rapid atrial pacing, this rhythm ultimately reverting back to atrial flutter in two. Ten patients received procainamide and 9 of the 10 had lengthening of the atrial flutter cycle length by a mean of 68 ms (1 patient continued to have atrial fibrillation). Then, using the same atrial pacing protocol, high right atrial pacing alone at a mean cycle length of 227 ms interrupted atrial flutter in all these patients, returning their rhythm to sinus rhythm. It is concluded that intravenous procainamide effectively augments the efficacy of rapid atrial pacing to convert atrial flutter to sinus rhythm.     

Celivarone for maintenance of sinus rhythm and conversion of atrial fibrillation/flutter

Celivarone in Atrial Fibrillation/Atrial Flutter. Introduction: Celivarone, a new noniodinated benzofuran derivative pharmacologically related to dronedarone and amiodarone, has been shown to have antiarrhythmic properties at a molecular level. The purpose of the 2 trials presented here (MAIA and CORYFEE) was to assess celivarone efficacy in the maintenance of sinus rhythm postcardioversion and for the conversion of atrial fibrillation (AF)/atrial flutter (AFL). Methods and Results: In the MAIA trial, 673 patients with AF/AFL recently converted to sinus rhythm were randomly assigned to receive 50, 100, 200, or 300 mg once‐daily dosing of celivarone; 200 mg daily of amiodarone preceded by a loading dose of 600 mg for 10 days; or placebo. At 3 months’ follow up, no significant difference was observed in time to AF/AFL relapse among the various celivarone groups and placebo. However, fewer symptomatic AF/AFL recurrences were observed in the lower‐dose celivarone groups (26.6% for celivarone 50 mg [P = 0.022] and 25.2% for celivarone 100 mg [P = 0.018] vs 40.5% for placebo at 90 days). Fewer adverse events were observed with the use of celivarone and placebo than amiodarone. In the CORYFEE study, 150 patients with AF/AFL were randomly assigned to once‐daily celivarone dosing of 300 or 600 mg, or placebo, for a 2‐day treatment period. There was no significant difference in the rate of spontaneous conversion to sinus rhythm between the treatment and control groups. Conclusions: In these studies, celivarone does not appear to be efficacious in the maintenance of sinus rhythm in AF/AFL patients or for the conversion of AF/AFL patients. (J Cardiovasc Electrophysiol, Vol. 23, pp. 462‐472, May 2012)     

Intravenous flecainide versus verapamil for acute conversion of paroxysmal atrial fibrillation or flutter to sinus rhythm

In a single-blind randomized study, the efficacy of intravenous flecainide (2 mg/kg/10 minutes) versus verapamil (10 mg/1 minute) was assessed in 40 patients with paroxysmal atrial fibrillation (AF) or atrial flutter (AFI). The treatment was considered successful if sinus rhythm occurred within 1 hour. Of 20 patients receiving flecainide, 14 of 17 (82%) with AF converted to sinus rhythm, but in 3 patients with AFI flecainide failed. All patients treated with verapamil (17 AF, 3 AFI) showed lower ventricular rates after 1 hour; however, only 1 (6%) with AF converted to sinus rhythm and 1 (6%) converted to AFI. Patients who did not convert to sinus rhythm after treatment with verapamil were treated with flecainide and observed for another hour. After the change to flecainide, 9 of 15 patients (60%) with AF still converted. Thus, 23 of 32 patients (72%) with AF and none of 7 with AFI converted to sinus rhythm after treatment with flecainide. Conversion to sinus rhythm was achieved in 19 of 22 patients (86%) when AF lasted less than 24 hours and in 4 of 10 (40%) when the arrhythmia lasted greater than 24 hours. Transient adverse effects were noted in 10 patients (26%) after flecainide. In summary, flecainide is an effective and safe drug for conversion of paroxysmal AF to sinus rhythm, but ineffective for AFI. Verapamil appears to be of no use for conversion of AF or AFI to sinus rhythm.     

Transient atrial dysfunction after conversion of chronic atrial fibrillation to sinus rhythm

Although conversion of atrial fibrillation (AF) to sinus rhythm can usually be accomplished by electrical or drug therapy, effective atrial systole may not be restored. To investigate the return of atrial transport function and its relation to the duration of the arrhythmia, Doppler echocardiography was performed after conversion in 18 patients with acute AF (less than or equal to 1 week duration), 14 patients with chronic AF (greater than 1 week duration) and 15 control patients. Flow velocities during rapid filling (E wave) and atrial systole (A wave) were measured in both left and right ventricles. Patients in the acute AF group had left ventricular A waves (49 +/- 4 cm/s) and A/E ratios (0.97 +/- 0.1) similar to those of the control patients (55 +/- 7 cm/s, 0.87 +/- 0.08, respectively). In contrast, patients in the chronic AF group had much smaller A waves (19 +/- 5 cm/s) and A/E ratios (0.30 +/- 0.08) than those in the other 2 groups (p less than 0.001). Five patients with chronic AF (36%) had complete left atrial paralysis (A/E = 0) despite normal sinus P waves. Measurements in the right ventricle showed similar differences among the groups. Patients with chronic AF who maintained sinus rhythm showed an increase in A/E ratio to control levels, from 0.45 +/- 0.1 to 0.93 +/- 0.1 (p = 0.003) at 48 days (average) after conversion. Thus, atrial transport function is normal after brief periods of AF, but reduced or absent when conversion is achieved after the arrhythmia has been sustained greater than 1 week.(ABSTRACT TRUNCATED AT 250 WORDS)     

阵发性房颤自行转复的预测性

目的 发现预测房颤病人自行转复的相关因素,并初步探讨其临床意义.方法 采用Logistic回归分析法分析和比较1988年9月至1998年9月我院收治的192例发病时间＜72 h的房颤自行转复和非自行转复病人的临床特点和超声心动检查结果.结果 入院时房颤持续时间＜24 h的自行转复病人和非自行转复病人分别为118例(89.4%)和40例(66.7%).结论 房颤发作时间＜24 h是房颤自行转复的唯一预测指标.对自行转复可能性大的病人,可延缓使用转复心律的药物和直流电转复.