Ibutilide versus amiodarone in atrial fibrillation: a double-blinded,randomized study

OBJECTIVE: Ibutilide, a class III antiarrhythmic drug, has been shown to convert atrial fibrillation to sinus rhythm more rapidly than procainamide or sotalol. Our objective was to compare the efficacy and safety of ibutilide and amiodarone in patients after cardiac surgery. DESIGN: Prospective, randomized, double-blinded study. SETTING: Intensive care unit of a university hospital. PATIENTS: Forty adults with an onset of atrial fibrillation within 3 hrs after admission. INTERVENTIONS: Before the administration of antiarrhythmic drugs, a 24-hr Holter electrocardiograph was attached. Patients in the ibutilide group received ibutilide 0.008 mg/kg body weight over 10 mins; treatment was repeated if atrial fibrillation or flutter persisted. If sinus rhythm was not achieved within 4 hrs, amiodarone 5 mg/kg was administered over 30 mins, followed by amiodarone 15 mg/kg over 24 hrs. Patients in the amiodarone group received amiodarone 5 mg/kg over 30 mins, followed by amiodarone 15 mg/kg over 24 hrs if atrial fibrillation or flutter continued. MEASUREMENTS AND MAIN RESULTS: Within the first 4 hrs, atrial fibrillation was converted in nine of 20 patients (45%) in group ibutilide and in ten of 20 patients (50%) in group amiodarone (not significant). Mean time for conversion overall was 385 mins in group ibutilide and 495 mins in group amiodarone (not significant). In group amiodarone, the protocol was discontinued in two patients because of severe arterial hypotension. Atrial fibrillation recurred in 11 of 20 patients (55%) in group ibutilide and in seven of 20 patients (35%) in group amiodarone (not significant). Ventricular arrhythmia did not occur during the first 24 hrs of the protocol. CONCLUSIONS: Ibutilide has no significant advantage over amiodarone for the conversion of atrial fibrillation to sinus rhythm in either time to conversion or conversion overall, but severe hypotension was not seen with ibutilide.     

Pharmacological management of atrial fibrillation: an update

Therapy of atrial fibrillation remains difficult in many patients. There is increasing awareness that antiarrhythmic drug therapy instituted to maintain sinus rhythm after successful cardioversion of atrial fibrillation may pose a substantial risk to the patient. Therefore, results of prospective randomized trials are needed to allow a more evidence-based approach to the treatment of this common arrhythmia. Two recently published studies have shown superiority of amiodarone over conventional antiarrhythmic drugs in maintaining sinus rhythm. The largest such study published today, the Canadian Trial in Atrial Fibrillation (CTAF), has randomized 403 patients to amiodarone or to sotalol or propafenone. At the end of the observation period, amiodarone-treated patients were significantly more likely to remain in sinus rhythm than conventionally treated patients. A number of new antiarrhythmic drugs, mainly class III substances, are currently developed for the treatment of atrial fibrillation or atrial flutter. Ibutilide has recently been released for intravenous administration, attempting pharmacological cardioversion of atrial fibrillation/atrial flutter. It has been evaluated in a number of prospective trials, which showed a higher conversion rate in patients with atrial flutter. Dofetilide is another new compound developed mainly for maintenance of sinus rhythm after restoration of sinus rhythm. It has been evaluated in two prospective, randomized, placebo-controlled trials; moreover, analysis of the DIAMOND trials showed effectiveness of dofetilide in maintaining sinus rhythm in patients with depressed left ventricular function without increased mortality when compared with placebo. Finally, several ongoing studies compare the therapeutic strategy of controlling ventricular rate in atrial fibrillation compared with the strategy of maintaining sinus rhythm. These trials will help to optimize therapy in atrial fibrillation, the most commonly encountered arrhythmia.     

Must antidysrhythmic agents be given to all patients with new-onset atrial fibrillation?

We investigated the spontaneous conversion rate of new-onset atrial fibrillation (AF) in emergency department patients and the recurrence rate of AF during a 1 month follow-up period. Sixty-six consecutive hemodynamically stable patients presenting to a university hospital emergency department with new-onset atrial fibrillation (less than 72 hours duration) comprised the study population. Patients were initially monitored for 8 hours and observed for spontaneous conversion of AF to sinus rhythm. If conversion did not occur in the first 8 hours, an oral loading dose (600 mg) of propafenone was given, and patients were observed for an additional 8 hours. All patients were reevaluated at 24 hours and at 1 month. The spontaneous conversion rate in patients presenting within 6 hours of AF onset during the initial 8-hour observation period was 71%. The spontaneous conversion rate for all patients during the initial observation period was 53%. The conversion rates between patients presenting "early" (less than 6 hours) and "late" (7-72 hours) were significantly different (P < 0.001). Many patients with new-onset AF, especially those with atrial fibrillation duration less than 6 hours, may need observation only, rather than immediate intervention, to treat their dysrhythmia.     

Intravenous Propafenone Versus Intravenous Amiodarone in the Management of Atrial Fibrillation of Recent Onset: A Placebo-Controlled Study

The efficacy and safety of intravenous propafenone, amiodarone, or placebo were compared in the treatment of atrial fibrillation (AF) of recent onset (duration ≤ 48 hours). Methods: 143 patients (77 men, mean age 63 ± 12 years) were studied, of whom 46 received propafenone (2 mg/kg over 15 minutes followed by 10 mg/kg over the next 24 hours), 48 received amiodarone (300 mg intravenously over 1 hour, followed by 20 mg/kg over the next 24 hours, plus 1,800 mg/day orally, in 3 divided doses), and 49 received placebo (the equivalent amount of saline IV over 24 hours). Digoxin was administered to all patients who had not previously received it. Results: Conversion to normal sinus rhythm occurred in 36 of 46 patients (78.2%) receiving propafenone, in 40 of 48 patients (83.3%) receiving amiodarone, and in 27 of the 49 (55.10%) controls (P < 0.02, drug vs placebo, between drugs NS). The mean time to conversion was 2 ± 3 hours for propafenone, 7 ± 5 hours for amiodarone, and 13 ± 9 for placebo (P < 0.05). Patients who converted had smaller atria than those who did not (diameter: 42.7 ± 5 vs 47.2 ± 7 mm, P < 0.001 for all). Treatment was discontinued in one patient in the amiodarone group because of an allergic reaction and in two patients in the propafenone group because of excessive QRS widening. No side effects were observed in the placebo group. Conclusions: Both drugs tested intravenously were equally effective and safe for the rapid conversion of recent-onset atrial fibrillation to sinus rhythm. However, propafenone offered the advantage of more rapid conversion than amiodarone.     

Management of atrial tachyarrhythmias in the critically ill: A comparison of intravenous procainamide and amiodarone

Objective To compare the efficacy and safety of intravenous (IV) amiodarone and procainamide for the treatment of atrial tachyarrhythmias (AT) in the critically ill.Design In this prospective study, patients were allocated to drug treatment on the basis of hospital identification number, even for procainamide and odd for amiodarone.Setting Patients were recruited from a teaching hospital ICU and did not include postoperative cardiac patients.Patients and participants 26 patients with AT sustained for at least 1 h and failure to respond to correction of possible precipitating factors were entered in the study. Exclusion criteria were systolic blood pressure (SBP)<80 mmHg, and known hypersensitivity to either drug. Two patients with chronic atrial fibrillation (who received amiodarone) were later excluded from the analysis. In the final analysis, 14 patients received procainamide and 10 amiodarone.Interventions IV amiodarone (3 mg/kg followed by 10 mg/kg/24h, with repeat dose of 3 mg/kg at 1 h if no response) or IV procainamide (10 mg/kg at 1 mg/kg/min followed by infusion of 2–4 mg/min for 24 h, with repeat dose of 5 mg/kg at 1 h if no response).Measurements and results In the procainamide group 10/14 (71%) and in the amiodarone group 7/10 (70%) had converted to sinus rhythm by 12 h. There was no significant difference in response between the groups. SBP was not significantly different from baseline after administration of either drug.Conclusions Procainamide and amiodarone appear to be safe and equally effective in the treatment of AT in the critically ill.     

Conversion of atrial fibrillation to sinus rhythm during treatment with intravenous esmolol or diltiazem: a prospective, randomized comparison

Prior studies have suggested that intravenous diltiazem reduces the probability of spontaneous conversion of atrial fibrillation (AF) to sinus rhythm in the electrophysiology laboratory and in patients with postoperative AF. Whether diltiazem exerts the same effect in patients presenting to the emergency department (ED) with spontaneous AF is unclear. Fifty patients presenting to the ED with new-onset or paroxysmal AF and a rapid ventricular rate (>100 beats per minute) were randomly assigned to receive intravenous diltiazem or esmolol during the first 24 hours of presentation. Conversion to sinus rhythm occurred in 10 patients (42%) in the diltiazem group compared with 10 patients (39%) in the esmolol group (P = 1.0). Diltiazem does not decrease the likelihood of spontaneous conversion of AF to sinus rhythm in the ED setting.     

Management of patients with acute atrial fibrillation in the ED

Background

Patients with acute atrial fibrillation with a history of mild structural heart disease could be considered for rhythm conversion.

Methods

Patients received intravenous flecainide, propafenone, or amiodarone on presentation and a second dose after 6 hours if atrial fibrillation persisted. No randomization was used, and drugs were given at the discretion of the treating physician. Primary end point was rhythm conversion within the first 6 hours from presentation. Secondary end points included rhythm conversion, time to rhythm conversion, and adverse drug effects within 24 hours.

Results

Among the 378 patients enrolled, 37 (10%) recovered sinus rhythm before therapy was given. Of the remaining 341 patients, 43 (13%) received flecainide, 187 (55%) received propafenone, and 111 (32%) received amiodarone. Baseline clinical characteristics were homogeneous among groups. Rhythm conversion was obtained in 87% of treated patients overall. Within 6 hours, the primary end point was achieved in a higher proportion in the flecainide and propafenone groups (72% and 55%, respectively) as compared with the amiodarone group (30%; P < .001). The mean time to the end point overall was shorter in the flecainide and propafenone groups (178 ± 227 and 292 ± 285 minutes, respectively) as compared with the amiodarone group (472 ± 269 minutes; P < .001). Length of in-hospital stay in the amiodarone group was significantly higher (26.1 ± 22.4 hours) compared with the flecainide and propafenone groups (8.9 ± 10.3 and 11.0 ± 13.8 hours; respectively; P = .001). No significant differences were found in adverse drug effects.

Conclusions

Flecainide and propafenone achieve rhythm control in a higher proportion of patients as compared with amiodarone within a 6-hour management.     

Intravenous amiodarone for acute pharmacological conversion of atrial fibrillation in the emergency department

Atrial fibrillation (AF) is the most common arrhythmia seen in patients presenting to the emergency department (ED). Pharmacological conversion of atrial fibrillation to normal sinus rhythm (NSR) may be a feasible management strategy in selected patients. Recent guidelines have recommended intravenous amiodarone, a class III antiarrhythmic agent, for the conversion of AF to NSR. The purpose of this review is to examine the published evidence for the efficacy of IV amiodarone for the acute conversion of AF to NSR in the ED. Currently available data from 11 randomized, controlled trials and 3 meta analyses do not support the use of conventional doses of IV amiodarone for acute conversion in the ED. High dose IV or combined IV and oral administration may be effective as early as 8 hours in patients with recent-onset AF of <48 hour duration in patients without contraindications to these high dose regimens. There are no data to support the use of IV amiodarone for acute conversion in patients with an ejection fraction of <40% or clinical heart failure, so its use in these scenarios should be limited to symptomatic patients who are refractory to electrical conversion. More well-designed studies are required to determine the role of IV amiodarone for the acute conversion of AF in the ED.     

High-dosage continuous amiodarone therapy to treat new-onset supraventricular tachyarrhythmias in surgical intensive care patients: an observational study

BACKGROUND: New-onset supraventricular tachyarrhythmias (SVTA) are a complication contributing significantly to morbidity and mortality in surgical intensive care unit (SICU) patients. Although only few data on efficiency can be found in the literature, class III antiarrhythmics have become popular in the treatment of SVTA in critically ill patients. SETTING: 12-bed general and surgical ICU in a university teaching hospital. DESIGN: Observational, retrospective study. PATIENTS: 131 SICU patients with SVTA (narrow-complex non-sinus tachyarrhythmias with heart rates > or = 100 bpm). INTERVENTION: High-dosage amiodarone infusion according to an institutional protocol. MEASUREMENTS: Hemodynamic data, acid-base status, and single organ functions were obtained in all patients before amiodarone infusion and at 12, 24, and 48 hours afterwards. Patients were divided into responders and nonresponders. Amiodarone infusion (mean dosage 24 h: 1625+/-528 mg; 48 h: 2708+/-895 mg) restored sinus rhythm in 54% of study patients within 12 h, in 64% within 24 h, and in 75% within 48 h. Heart rate, central venous pressure, and milrinone requirements significantly decreased in all patients; this was accompanied by a significant increase in stroke-volume index and mean arterial pressure. Serum concentrations of creatinine and bilirubin increased in all patients. CONCLUSION: High-dosage continuous amiodarone infusion during a period of 48 hours resulted in restoration of SR in 75% of SICU patients with new-onset SVTA and moderate to severe multiple-organ dysfunction syndrome. A significant improvement in cardiocirculatory function was more pronounced in responders but could be demonstrated irrespective of restoration of sinus rhythm in all patients. Apart from a possibly amiodarone-mediated increase in concentrations of creatinine and bilirubin, no major drug-related adverse effects occurred during the observation period.     

When the body and appendage of the left atrium disagree: "Focal" atrial fibrillation-implications for atrial thrombus formation and risk of thromboembolism.

A case is presented of a man who had 5 hours of atrial fibrillation followed by spontaneous conversion and maintained sinus rhythm that persisted as shown by surface electrocardiography. Transesophageal echocardiography performed 24 hours after electrocardiographic conversion documented an atrial fibrillation pattern within the left atrial appendage, with a normal sinus Doppler pattern in the body of the left atrium. This apparent regional discrepancy in atrial function may partially explain the increased risk for "late" thromboembolism among patients with atrial fibrillation who appear to be successfully converted with sustained sinus rhythm.     

Controlling Paroxysmal Atrial Fibrillation by a Combination of Amiodarone and Flecainide: Description of a Case With 15-Year Follow-up

A 77-year-old man with no known cardiac disease has had paroxysmal atrial fibrillation for 35 years with disabling symptoms and poor exercise tolerance when not in sinus rhythm, and he did not respond to conventional therapy. Fifteen years ago he was placed on amiodarone. His arrhythmia converted to atrial flutter with a flutter rate below 200 beats/min; DC cardioversion at 3 months led to transient sinus rhythm. At 5 months he converted spontaneously to sinus rhythm and had very few recurrences until 4 years later when he began to experience further frequent recurrences when the dose was reduced from 400 mg/day to 200 mg/day. Redosing at the higher dose led to skin discoloration; amiodarone was then replaced with sotalol, which the patient did not tolerate. After 9 months with efforts to rate control with various agents, amiodarone was reintroduced at 400 mg/day, which achieved full control, but to obviate the development of skin changes, flecainide was added at a dose of 100 mg twice a day, and the dose of amiodarone was gradually reduced to 200 mg/day. This combination regimen has produced no side effects or organ toxicity, although a degree of hypogonadism developed. It responded well to testosterone replacement. On the combination regimen, there have been no symptomatic arrhythmia recurrences over 8 years. Amiodarone and flecainide may have additive or synergistic effects in maintaining sinus rhythm in atrial fibrillation; the antiarrhythmic property of amiodarone is likely to minimize or nullify the proarryhthmic reactions of flecainide during combination therapy. This combination regimen may allow the extension of the use of flecainide in controlling refractory atrial flutter and fibrillation in patients with structural cardiac disease. The efficacy and safety of the combination regimen of the two drugs should be addressed in controlled clinical trials.     

Conversion of Recent-Onset Atrial Fibrillation to Sinus Rhythm: Effects of Different Drug Protocols

In a population of 417 hospitalized patients, the efficacy and safety of different drug regimens administered to convert atrial fibrillation (AF) of recent anset (≤ 7 days duration) to sinus rhythm were evaluated. All patients were in NYHA Class ≤ 2, and free of heart failure. They were randomly allocated to treatment with placebo in 121 patients; IV amiodarone, 5 mg/kg bolus, followed by 1.8 g/24 hours in 51 patients; IV propafenone, 2 mg/kg bolus, followed by 0.0078 mg/kg/min in 57 patients; p.o. propafenone, 600 mg p.o. in a single dose in 119 patients; and p.o. flecainide, 300 mg p.o. in a single dose in 69 patients. All patients were continuously monitored by Holter ECG, and the number of conversions to sinus rhythm was measured at 1, 3, and 8 hours. Results: (1) IV propafenone resulted in a higher conversion rate within 1 hour compared with the oral loading regimens of propafenone or flecainide, but the conversion rates at 3 and 8 hours were comparable, approximately 75% at 8 hours; 2) IV amiodarone was not different from placebo until 8 hours when it was associated with 57% of conversions; (3) conversion to sinus rhythm at 8 hours was observed in 37% of the placebo treated patients. Serious adverse effects occurred in few patients: two patients treated with flecainide and one treated with IV propafenone experienced left ventricular decompensation; one patient treated with placebo and two treated with flecainide had atrial flutter with rapid ventricular response. In conclusion, single-dose, oral loading with propafenone or flecainide are acceptable alternatives to conventional drug regimens in selected hospitalized patients. In addition, the measure of a placebo effect is mandatory in studies of recent-onset AF.     

口服普罗帕酮与胺碘酮联合电复律转复持续性房颤的随机对照试验

目的比较普罗帕酮与胺碘酮联合电复律转复持续性心房颤动及维持窦性心律的疗效与安全性。方法将60例基础疾病治疗良好的持续性房颤患者随机分为两组,每组各30例。普罗帕酮组:普罗帕酮600mg顿服后观察6h,未转复者予电复律,并以最低有效量口服维持窦律;胺碘酮组:胺碘酮600mg分3次口服,连服7天,未转复者电复律,以最低有效量维持窦律。结果单纯药物复律,普罗帕酮组4例,胺电酮组3例,联合电复律两组分别转复25例和22例,两组早期有效率分别为90.0%和80.0%,晚期有效率分别为73.3%和70.0%,两组比较差异无统计学意义。住院时间普罗帕酮组短于胺碘酮组(P<0.001)。普罗帕酮组1例服药后出现一过性低血压,放弃复律,经对症治疗后好转;胺碘酮组4例服药后恶心、呕吐,未能坚持负荷量连服7天;但两组副反应发生率差异无统计学意义。结论普罗帕酮与胺碘酮联合电复律治疗持续心房颤动安全而有效,但普罗帕酮起效快,可相对减少患者的住院时间。     

When the Body and Appendage of the Left Atrium Disagree: “Focal” Atrial Fibrillation—Implications for Atrial Thrombus Formation and Risk of Thromboembolism

A case is presented of a man who had 5 hours of atrial fibrillation followed by spontaneous conversion and maintained sinus rhythm that persisted as shown by surface electrocardiography. Transesophageal echocardiography performed 24 hours after electrocardiographic conversion documented an atrial fibrillation pattern within the left atrial appendage, with a normal sinus Doppler pattern in the body of the left atrium. This apparent regional discrepancy in atrial function may partially explain the increased risk for “late” thromboembolism among patients with atrial fibrillation who appear to be successfully converted with sustained sinus rhythm. (J Am Soc Echocardiogr 1999;12:1097-1100.)     

Antiarrhythmic drugs for atrial fibrillation: focus on dronedarone

Patients with atrial fibrillation have an increased risk of stroke and heart failure, as well as impairment of their quality of life. Most trials have primarily focused on the prevention of stroke and heart failure, and the improvement of symptoms in these patients. More recently, a rate-control strategy has been reported to be a noninferior strategy compared with a rhythm-control strategy in atrial fibrillation patients. Many different classes of antiarrhythmic drugs have been used for rhythm control, with inconsistent results and adverse effects on mortality and morbidity. Of the available antiarrhythmic drugs, amiodarone is the single most effective drug in the prevention of atrial fibrillation recurrences and maintaining sinus rhythm; however, it is vastly limited by its various systemic side effects, especially those observed with long-term use. However, recent trial data from a new antiarrhythmic agent, dronedarone, suggest that this drug may be a safe alternative to amiodarone; however, its long-term efficacy and safety still require exploration.     

Propafenone versus amiodarone in field treatment of primary atrial tachydysrhythmias

Thirty-nine patients with paroxysmal atrial fibrillation or supraventricular tachycardia randomly received amiodarone or propafenone intravenously at home. Fifteen patients received amiodarone and 24 received propafenone; 87.5% of the patients who received propafenone and 40% of the patients who received amiodarone were converted at home to sinus rhythm (P less than .005). The median time of conversion was 10 minutes (range 5 to 35) for propafenone and 60 minutes (range 20 to 130) for amiodarone (P less than 0.005). When either drug failed to terminate atrial tachydysrhythmias at home, the same drug always restored sinus rhythm with subsequent oral treatment during hospitalization. No major side effects were observed after the infusion of either drug. The incidence of minor side effects was not significantly different between the two drugs. Both the drugs are efficacious and safe in the acute management of primary supraventricular tachydysrhythmias. Propafenone showed a greater rapidity of action.     

Intravenous amiodarone bolus for treatment of atrial fibrillation in patients with advanced congestive heart failure or cardiogenic shock

BACKGROUND: The clinical course of patients with advanced organic heart disease is often complicated by the occurrence of atrial fibrillation. Slowing the ventricular rate and, if possible, restoration of normal sinus rhythm is crucial but difficult in the state of decreased ventricular function. METHODS: We included 78 consecutive patients with atrial fibrillation and heart rate above 135 beats min(-1) in an observational, uncontrolled study in the coronary care unit of a tertiary care center. Thirty-nine patients suffered from advanced congestive heart failure, 26 patients had pulmonary edema, and 13 patients were in cardiogenic shock. All patients were treated with 450 mg amiodarone given as a single intravenous bolus through a peripheral venous access without further infusion. Ventricular heart rate and cardiac rhythm were measured within 30 minutes after drug administration. Cardiac rhythm was monitored for 24 hours. The site of venous access was examined 30 minutes after drug administration and every 6 hours until the needle was removed after a maximum of 48 hours. RESULTS: Twenty-five patients (32%) converted to normal sinus rhythm within 30 minutes. Another 15 (19%) reverted into sinus rhythm during the following 24 hours. Within 30 minutes after amiodarone administration, ventricular heart rate decreased significantly from 152 +/- 12 to 88 +/- 17 (p < 0.0001) beats min(-1) in patients who converted to sinus rhythm and from 157 +/- 14 to 98 +/- 16 beats min(-1) in patients who did not. The degree of reduction in heart rate was similar among patients presenting with exacerbated congestive heart failure, pulmonary edema, or cardiogenic shock. Systolic blood pressure decreased in two patients, from 115 to 80 mmHg and from 130 to 100 mmHg, but was reversible after 10 and 90 minutes respectively without specific intervention. No proarrhythmia or clinical relevant bradycardia was observed, and no inflammation detected at the site of venous access. CONCLUSIONS: Amiodarone, given as a single intravenous bolus through a peripheral vein rapidly reduced ventricular rate and was well tolerated in patients with atrial fibrillation, even in the presence of congestive heart failure and cardiogenic shock.     

预激综合征合并房颤20例急诊治疗临床分析

目的 分析预激综合征合并房颤的急诊治疗效果.方法 回顾性分析20例预激综合征合并房颤病例的电复律、药物复律疗效.结果 盐酸普罗帕酮使用11例次,转复7例,好转4例;利多卡因使用5例次,转复3例;急诊血流动力学障碍3例和药物复律无效2例,经直流电复律一次性转复为窦性心律.结论 普罗帕酮和利多卡因是急诊治疗预激综合征合并房颤常规使用的有效复律药物,血流动力学障碍或药物复律无效者宜采取电复律.     

胺碘酮转复心房颤动的疗效分析

目的观察重叠应用静脉及口服胺碘酮治疗并发于器质性心脏病的心房颤动的临床疗效及安全性。方法39例心房颤动患者先给予静脉负荷量胺碘酮(150~300 mg)后,继之以0.6 mg/min静脉点滴维持48 h;同时口服胺碘酮治疗,2周内给胺碘酮负荷量7 g,然后维持量0.2 g/d。观察临床疗效及不良反应。结果32例(82.1%)患者成功转复为窦性心律,于2 h、2~24 h、24~48 h、2~7 d转复率分别为12.8%、28.2%、23.1%、18.0%。未转复组患者左房径大于转复组(P<0.05),而射血分数明显低于转复组(P<0.05),这可能是7例患者未转复的原因。2例患者用药后出现窦性心动过缓,1例出现恶心、腹胀,经减药后恢复。结论静脉及口服胺碘酮治疗并发于器质性心脏病的心房颤动是有效且较安全的方法。     

Effectiveness of direct-current cardioversion for treatment of supraventricular tachyarrhythmias,in particular atrial fibrillation,in surgical intensive care patients

OBJECTIVE: To evaluate primary success rate and effectiveness of direct-current cardioversion in postoperative critically ill patients with new-onset supraventricular tachyarrhythmias. DESIGN: Prospective intervention study. SETTING: Twelve-bed surgical intensive care unit in a university teaching hospital. PATIENTS: Thirty-seven consecutive, adult surgical intensive care unit patients with new-onset supraventricular tachyarrhythmias without previous history of tachyarrhythmias. INTERVENTIONS: Direct-current cardioversion using a monophasic, damped sinus-wave defibrillator. Energy levels used were 50, 100, 200, and 300 J for regular supraventricular tachyarrhythmias (n = 6) and 100, 200, and 360 J for irregular supraventricular tachyarrhythmias (n = 31). MEASUREMENTS AND MAIN RESULTS: None of the patients was hypoxic, hypokalemic, or hypomagnesemic at onset of supraventricular tachyarrhythmia. Direct-current cardioversion restored sinus rhythm in 13 of 37 patients (35% primary responders). Most patients responded to the first or second direct-current cardioversion shock. Only one of 25 patients requiring more than two direct-current cardioversion shocks converted into sinus rhythm. Primary responders were significantly younger and demonstrated significant differences in arterial Po2 values at onset of supraventricular tachyarrhythmias compared with nonresponders. At 24 and 48 hrs, only six (16%) and five (13.5%) patients remained in sinus rhythm, respectively. CONCLUSIONS: In contrast to recent literature, direct-current cardioversion proved to be an ineffective method for treatment of new-onset supraventricular tachyarrhythmias and, in particular, atrial fibrillation with a rapid ventricular response in surgical intensive care unit patients.