Atrial Flutter Patients Research Articles

The Importance of Typical Atrial Flutter in Patients with Repaired Congenital Heart Disease and Intra-Atrial Reentrant Tachycardia

The Importance of Typical Atrial Flutter in Patients with Repaired Congenital Heart Disease and Intra-Atrial Reentrant Tachycardia

Extraction and Analysis of $\hbox{T}$ Waves in Electrocardiograms During Atrial Flutter

Analysis of T waves in the ECG is an essential clinical tool for diagnosis, monitoring, and follow-up of patients with heart dysfunction. During atrial flutter, this analysis has been so far limited by the perturbation of flutter waves superimposed over the T wave. This paper presents a method based on missing data interpolation for eliminating flutter waves from the ECG during atrial flutter. To cope with the correlation between atrial and ventricular electrical activations, the CLEAN deconvolution algorithm was applied to reconstruct the spectrum of the atrial component of the ECG from signal segments corresponding to TQ intervals. The locations of these TQ intervals, where the atrial contribution is presumably dominant, were identified iteratively. The algorithm yields the extracted atrial and ventricular contributions to the ECG. Standard T-wave morphology parameters (T-wave amplitude, T peak-T end duration, QT interval) were measured. This technique was validated using synthetic signals, compared to average beat subtraction in a patient with a pacemaker, and tested on pseudo-orthogonal ECGs from patients in atrial flutter. Results demonstrated improvements in accuracy and robustness of T-wave analysis as compared to current clinical practice.

High-sensitivity troponin T as a marker of myocardial injury after radiofrequency catheter ablation

The aim of our study was to monitor radiofrequency catheter ablation-induced myocardial damage by measuring high-sensitivity cardiac troponin T (hs-cTnT). Serum concentrations of hs-cTnT (Elecsys 2010 system, Roche) were measured in 73 healthy blood donors and serially in 27 patients who had samples taken both before and 24 h after radiofrequency ablation (RFA) for atrioventricular nodal re-entry tachycardia (AVNRT), atrial fibrillation (AF) or right atrial flutter (AFL). Significant increases of hs-cTnT were seen in patients after RFA (AVNRT: P = 0.0115, AF: P = 0.0011, AFL: P = 0.0009). Postprocedural serum hs-cTnT correlated with the number of radiofrequency applications and with the duration of RFA procedure. Spearman's coefficient of rank correlation (r) were as follows: hs-cTnT versus RFA duration: r = 0.771 (P < 0.001); hs-cTnT versus number of pulses: r = 0.708 (P < 0.001). Patients with the diagnosis of AVNRT had lower serum hs-cTnT concentration after RFA compared with AFL (P < 0.0001) and AF (P < 0.0001) patients. Our data indicate that RFA causes a significant increase of serum hs-cTnT concentration that could be used to monitor myocardial injury.

Variation in Management of Recent-Onset Atrial Fibrillation and Flutter Among Academic Hospital Emergency Departments

Although recent-onset atrial fibrillation and flutter are common arrhythmias managed in the emergency department (ED), there is insufficient evidence to help physicians choose between 2 competing treatment strategies, rate control and rhythm control. We seek to evaluate variation in ED management practices for recent-onset atrial fibrillation and flutter patients at multiple Canadian sites and to determine whether hospital site was an independent predictor of attempted cardioversion. We conducted a cross-sectional survey by health records review on an observational cohort of all eligible adult recent-onset atrial fibrillation and flutter cases, with onset of symptoms less than 48 hours, treated at 8 academic hospital EDs during a 12-month period, and evaluated the variation in practice among sites for important management strategies. Among the 1,068 study patients, 88.3% had atrial fibrillation and 11.7% had atrial flutter. The proportion of cases managed with rhythm control was 59.4% (interhospital range 42% to 85%) and, among these, electrocardioversion was attempted first for 44.2% (range 7% to 69%). There was variation in most management strategies, including use of rate control drugs 54.9% (range 37% to 65%), choice of procainamide as rhythm control drug 62.1% (range 15% to 89%), referral to cardiology in the ED 30.7% (range 16% to 64%), use of heparin 13.7% (range 1% to 29%), and outpatient cardiology referral 43.0% (range 30% to 65%). Adverse events were relatively uncommon and transient for patients undergoing attempts at pharmacologic (13.0%) or electrocardioversion (12.1%). Overall, 83.3% of patients were discharged home from the ED (range 73% to 90%). After controlling for 12 covariates, multivariate logistic regression found that factors independently associated with attempted cardioversion were age (odds ratio [OR] 0.97; 95% confidence interval [CI] 0.95 to 0.98), history of electrocardioversion (OR 2.73; 95% CI 1.56 to 4.80), associated heart failure (OR 0.29; 95% CI 0.09 to 0.95), and hospital site (ORs ranged from 0.38 to 3.05). We demonstrated a high degree of variation in management approaches for recent-onset atrial fibrillation and flutter patients treated in academic hospital EDs. Individual hospital site, age, previous cardioversion, and associated heart failure were independent predictors for the use of rhythm control.

Evaluation of the Surface ECG in Detecting Isthmus Conduction Block after Ablation of Typical Atrial Flutter

To investigate the value of changes in P wave morphology and duration detected by surface electrocardiogram (ECG) during proximal coronary sinus (PCS) and low lateral right atrial (LLRA) stimulation as a marker for complete bidirectional isthmus conduction block in the procedure of typical atrial flutter ablation. Morphology, duration, and ratio of a positive terminal P wave were estimated in 52 typical atrial flutter patients before and after radiofrequency catheter ablation (RFCA). Atrial flutter ablation resulted in a complete bidirectional isthmus block in all 52 patients. The terminal portion of the P wave towards a positive morphology was detected in 90.7% (47/52) patients both during PCS and LLRA stimulation. These changes were predominantly observed in the inferior leads. Positive morphological changes of the terminal P wave portion and the measured P wave ratio (40% +/- 12%) in the inferior leads indicating bidirectional isthmus conduction block with a sensitivity of 87.5% and a specificity of 91.7% were observed. An increment of 20 ms or more in P wave duration during the PCS stimulation and 10 ms or more during the LLRA stimulation indicating the conduction block with a sensitivity of 90% and a specificity of 100%. The variation of P wave morphology and duration in inferior leads of the surface ECG is a helpful technique to assess the complete bidirectional isthmus conduction block in the procedure of typical atrial flutter ablation.

Peri-mitral atrial flutter in patients with atrial fibrillation ablation

Peri-mitral atrial flutter (PMFL) is commonly encountered in patients undergoing atrial fibrillation (AF) ablation. The purpose of this study was to determine the electrophysiologic characteristics, procedural success, and medium-term outcomes in patients with PMFL. The study consisted of 50 consecutive patients (45 men and 5 women, age 57 +/- 12 years) with PMFL following or during AF ablation. Of the 50 PMFLs, 24 occurred during AF ablation (16 at index ablation and 8 at repeat procedure for recurrent AF), and 26 developed during follow-up. Ablation of PMFL was performed by creating a linear lesion joining the mitral annulus to the left inferior pulmonary vein. The incidence of PMFL was higher in patients with mitral isthmus (MI) ablation performed during AF ablation, prior to the development of PMFL, than in those in whom MI ablation was not performed (23% vs 8%, P = .04). Following the procedure, PMFL was more frequent in patients with prior MI ablation than in those without (41% vs 15%, P <.01). Seventy percent (35/50) were terminated by ablation with 6.4 +/- 6.9 minutes of radiofrequency application. Among patients in whom PMFL terminated, supplemental ablation was required for bidirectional conduction block in 66% (23/35). MI block was achieved in 92% (46/50) using 13.6 +/- 7.4 minutes of ablation. At mean follow-up of 19 +/- 4 months, 96% of patients were free from PMFL. PMFL can be terminated by MI ablation, but the procedure is proarrhythmic. Supplemental ablation is necessary to establish bidirectional block of the line despite termination of PMFL in the majority of patients.

New Pharmacological Agents for Arrhythmias

Despite advances in catheter ablation techniques and device-based therapies for cardiac arrhythmias, antiarrhythmic drugs remain essential components of any comprehensive therapeutic strategy. Antiarrhythmic drug therapy, however, has been limited by both incomplete efficacy and a substantial potential for cardiac and extracardiac toxicity. As a result, only a few new antiarrhythmic agents have successfully completed clinical development programs and reached routine clinical usage over the past 20 years. Antiarrhythmic drugs may be indicated for ventricular tachycardia, sudden death prevention, or specific types of supraventricular arrhythmia. Implantable cardioverter-defibrillator (ICD) therapy has evolved as the primary treatment for most life-threatening ventricular arrhythmias, and antiarrhythmic drugs for these rhythms are currently mostly used either as acute interventions or as adjuncts to chronic ICD therapy. Although numerous trials have evaluated the effect of antiarrhythmic drugs to decrease ICD shocks or therapies, such data have yet to provide the sole basis for approval for any new agent. At the same time, drug therapy for atrial arrhythmias is often limited by the drug’s simultaneous effects on the ventricles, which has led to efforts to identify ionic channel targets specific to or preferentially located in the atria. The sustained outward K+ current (IKur, encoded by the Kv 1.5 subunit), the acetylcholine-activated outward K+ current (IKAch), and both peak and late atrial Na+ currents have therefore become potential targets for antiarrhythmic drug developers.1–4 Another approach has been to seek agents that synergistically affect multiple channels simultaneously, resulting in a net beneficial effect while minimizing toxicity. Other nontraditional targets for drug therapy that do not directly involve ion channels have also emerged as our understanding of the mechanisms of arrhythmias has improved. As a result, several new compounds are now at or near completion of phase 3 clinical trials, and other promising …

Role of Smoking in the Recurrence of Atrial Arrhythmias After Cardioversion

We aimed to determine whether smoking status affects the recurrence of atrial fibrillation or atrial flutter in patients after cardioversion. The clinical data of patients undergoing cardioversion for atrial flutter from January 1, 2000 to December 31, 2005 were prospectively collected. Arrhythmia recurrences were detected by retrospective review of comprehensive medical records and were determined using electrocardiography. The smoking history was prospectively collected through a standardized clinical form and subsequently categorized as lifetime nonsmoker, exsmoker, or current smoker. Univariate and multivariate associations with end points for clinical and lifestyle variables were assessed with Cox proportional hazards models. Women who were current smokers at cardioversion had a greater risk of atrial arrhythmia recurrence than did nonsmokers (hazard ratio 1.71, 95% confidence interval 1.10 to 2.67, p = 0.02). The increased risk of arrhythmia recurrence in female smokers was not seen in male smokers. Compared to lifetime nonsmokers, the mortality hazard ratio among men was 1.18 (95% confidence interval 0.88 to 1.58; p = 0.28) in exsmokers and 1.93 (95% confidence interval 1.20 to 3.11; p = 0.007) in current smokers. The risk of death after cardioversion was not increased in women. In conclusion, smoking is an independent predictor of atrial arrhythmia recurrence after cardioversion in women; however, an increased mortality risk, but not arrhythmia recurrence risk, was seen in men.

The Undetermined Geometrical Factors Contributing to the Transverse Conduction Block of the Crista Terminalis

The crista terminalis (CT) is known to be a functional barrier during typical atrial flutter (AFL). The relationship between the CT structural characteristics and its transverse conduction block, however, has not been understood well. This study consisted of AFL (group 1, N = 15) and non-AFL patients (group 2, N = 13). The CT structural characteristics were determined with intracardiac echocardiography. A 20-pole electrode catheter was located along the CT and pacing at progressively faster rates from either low anterolateral right atrium (LRA) or coronary sinus (CS) was applied. The CT height, width, and area were significantly greater in group 1 than in group 2 (P < 0.001). In both groups, at the longest pacing cycle length during CS pacing resulting in CT transverse conduction block at some levels, the width and area were significantly greater at the levels with block than at those without block. During LRA pacing, the area was also significantly larger at the levels with block than at those without in group 1, but not in group 2. The slope angle of CT ridge was significantly steeper at the levels with block than at those without in both groups (P < 0.01), but that was not the case with CS pacing. CT arborization in its inferior portion was more frequently documented in group 1 than group 2 (P < 0.05). The CT structural characteristics that may influence its transverse conduction differ between LRA and CS pacing. Steep slope and arborization of the CT are implicated as a geometric factor in its transverse conduction block.

Test Characteristics of Neck Fullness and Witnessed Neck Pulsations in the Diagnosis of Typical AV Nodal Reentrant Tachycardia

Claims in the medical literature suggest that neck fullness and witnessed neck pulsations are useful in the diagnosis of typical AV nodal reentrant tachycardia (AVNRT). Neck fullness and witnessed neck pulsations have a high positive predictive value in the diagnosis of typical AVNRT. We performed a cross-sectional study of consecutive patients with palpitations presenting to a single electrophysiology (EP) laboratory over a 1 year period. Each patient underwent a standard questionnaire regarding neck fullness and/or witnessed neck pulsations during their palpitations. The reference standard for diagnosis was determined by electrocardiogram and invasive EP studies. Comparing typical AVNRT to atrial fibrillation (AF) or atrial flutter (AFL) patients, the proportions with neck fullness and witnessed neck pulsations did not significantly differ: in the best case scenario (using the upper end of the 95% confidence interval (CI), none of the positive or negative predictive values exceeded 79%. After restricting the population to those with supraventricular tachycardia (SVT) other than AF or AFL, neck fullness again exhibited poor test characteristics; however, witnessed neck pulsations exhibited a specificity of 97% (95% CI: 90%-100%) and a positive predictive value of 83% (95% CI: 52%-98%). After adjustment for potential confounders, SVT patients with witnessed neck pulsations had a seven-fold greater odds of having typical AVNRT, p = 0.029. Although neither neck fullness nor witnessed neck pulsations are useful in distinguishing typical AVNRT from AF or AFL, witnessed neck pulsations are specific for the presence of typical AVNRT among those with SVT.

Methods to access the surgically excluded cavotricuspid isthmus for complete ablation of typical atrial flutter in patients with congenital heart defects

Cavotricuspid isthmus (CVTI)-dependent flutter in postoperative congenital heart disease patients is common and difficult to treat. The purpose of this study was to evaluate techniques for accessing excluded portions of the CVTI after Fontan or atrial switch procedures and completely ablating flutter. Patients who had undergone Fontan or atrial switch procedures and had CVTI-dependent flutter requiring ablation between 1990 and 2007 were identified. Flutters induced, methods for accessing the CVTI, use of intracardiac echocardiography, complications, and success rates were noted. Sixteen patients (44% males, mean age at ablation 28 years) were identified: 14 prior Fontan and 2 Mustard repair, with a total of 19 ablation procedures. In 13 (81%) of 16 patients, access to the entire CVTI could not be achieved via a systemic venous route. The excluded CVTI was accessed by retrograde transaortic approach in 6 and by anterograde transconduit puncture in 1 patient, with termination and lack of reinducibility of CVTI-dependent flutter achieved in all cases. One patient developed high-grade AV block requiring pacemaker therapy. Follow-up data (range 1-89 months, mean 29 months) were available for 18 of 19 procedures. CVTI atrial flutter recurred in 1 of 7 patients involving access to the pulmonary venous side. Even when surgical procedures exclude a portion of the CVTI, complete ablation of "typical" atrial flutter, including documentation of bidirectional block, can be achieved by novel approaches targeting the surgically excluded arrhythmogenic atrial tissue.

Action Potential Characteristics in the Sinus Venosa of Patients With and Without Atrial Flutter

A functional line of conduction block is often observed in the sinus venosa (SV) during typical atrial flutter (AFL). Little information, however, is available as to the action potential characteristics in the SV with respect to the functional block. Monophasic action potentials (MAPs) from the SV and lateral wall of the right atrium were recorded in 7 patients with paroxysmal AFL and 11 control patients. For both the control and AFL patients, the MAP duration at 90% repolarization (MAPD90) in the SV was longer, and the MAPD90 restitution slope was less steep than in the lateral wall. The MAPD90 in the SV in the AFL patients was slightly longer than that in the controls at the shortest cycle length (CL) tested (300 ms). However, the MAPD90s at longer CLs (350-700 ms), as well as the MAPD90 restitution slopes in the SV were comparable between the 2 groups. The MAPs in the SV are characterized by a long duration and flat restitution kinetics in humans. MAP properties to facilitate the development of conduction block in the SV are not appreciable in patients with paroxysmal typical AFL.

New methods for estimating local electrical activation rate during atrial fibrillation

Dominant frequency (DF) analysis is sometimes limited in its characterization of atrial fibrillation (AF), thus better methodology is needed. To develop methods for analyzing the AF signal without transformation to frequency space, and to compare the methods to DF analysis using both real and simulated data. Electrograms were obtained in 11 patients with paroxysmal or persistent AF. Atrial rate (AR) was estimated retrospectively from 8.4-s intervals acquired at 8 sites, using DF and 2 new methods: (1) Signals were converted into merged deflections (time complexes [TC]). Mean peak-to-peak cycle length was used to estimate AR. (2) The ensemble average (EA) was calculated with window size (w) ranging from 50 to 500 ms (frequency f = 2 to 20 Hz). The dominant peak in the root-mean-square power spectrum of EA versus w was used to estimate AR. Methods were compared using patient data, and in simulations using a Hanning pulse (2-mV peak, 50-ms duration, 120-ms period) with additive random noise, amplitude changes, and phase shift. Data from 10 atrial flutter patients were used to validate rate estimation under static conditions. From pooled AF data (N = 88 sites), mean atrial rate was 5.71 Hz (EA), 5.96 Hz (TC), and 5.72 Hz (DF). The mean absolute rate difference was 0.65 Hz (EA-TC), 0.58 Hz (EA-DF), and 0.50 Hz (TC-DF). In simulations, DF, TC, and EA, respectively, correctly predicted rate with additive random noise up to 0.13 mV, 1.4 mV, and 15.2 mV, random phase shift up to 46.3 ms, 28.8 ms, and 51.3 ms, and random amplitude variation ranging from 0 to 4 mV, 1.3 to 2.7 mV, and 0 to 4 mV. All methods accurately estimated rate during atrial flutter. Accurate rate estimation depends on signal periodicity and is influenced by random noise. The EA provides an accurate rate estimate of the periodic component of AF even at high noise levels.

Upper Turnover Portion of the Reentry Circuit for Typical and Reverse Typical Atrial Flutter

The posteromedial right atrium (PMRA) forms a block line during typical atrial flutter (AFL). However, whether upper turnover portion exists at the anterior or posterior superior vena cava (SVC) has not been determined. We performed right atrial mapping during AFL in 20 patients (typical AFL, n = 17; reverse typical AFL, n = 3) using an electroanatomical mapping system. Mean AFL cycle length was 224 +/- 20 ms and mean number of mapping points was 140 +/- 27. PMRA formed a block line during both typical and reverse AFL in all patients. However, in 16 of 17 patients mapped with typical AFL, PMRA did not extend superiorly to the orifice of the SVC and AFL wave propagated between the upper limit of the PMRA and the posterior SVC. In the remaining patient mapped with typical AFL, a double potential was recorded along the PMRA continuously between the orifices of the inferior vena cava (IVC) and SVC. In the three patients mapped with reverse typical AFL, a posterior barrier was detected from IVC to the upper limit of the PMRA and AFL wave propagated between the upper limit of the PMRA and the posterior SVC. Mean length from IVC to upper limit of the PMRA was 81 +/- 8% of the length from IVC to SVC. PMRA forms a functional block line during both typical and reverse typical AFL. The upper turnover portion of reentry circuit for AFL was observed between the upper limit of the PMRA and the posterior SVC in the majority of isthmus-dependent AFL patients.

Clinical Efficacy of Bepridil for Class I Antiarrhythmic Drug-Induced Atrial Flutter in Patients with Paroxysmal Atrial Fibrillation

Background: Class I antiarrhythmic drugs can promote the organization of atrial fibrillation (AF) and sometimes converts AF into atrial flutter (AFL) concomitant with difficulty of rate control. We studied the usefulness of Bepridil, which exhibits a class III‐like effect, for class I drug‐induced AFL in patients with paroxysmal AF.Methods: The study population consisted of 17 consecutive patients (15 men, mean age 65 ± 8 years) with AFL converted from paroxysmal AF following oral treatment of class IA or IC antiarrhythmic agents including pilsicainide (n = 8), cibenzoline (n = 5), flecainide (n = 2), aprindine (n = 1), and propafenone with cibenzoline (n = 1). After the occurrence of AFL, class I drug was replaced by bepridil with a dose of 100–200 mg per day in all patients.Results: After the treatment with bepridil, 15 (88%) out of the 17 patients restored sinus rhythm after 1 to 68 days (average of 21 days). In 12 (80%) of the 15 patients, sinus rhythm was maintained for an average of 23.6 months (range of 1 to 62 months) follow‐up period. Although torsade de pointes was not recognized, a marked QT prolongation (0.60 sec) was observed in one patient during the administration of bepridil at a daily dose of 200 mg. In this patient, QT interval was normalized (0.45 sec) after reduction of bepridil to 150 mg daily.Conclusion: Bepridil treatment may be safe and effective for class I drug‐induced AFL in patients with paroxysmal AF to restore and maintain sinus rhythm as an alternative therapy for catheter ablation. However, the QT interval must be carefully monitored during this medication.

Automated external cardioversion defibrillation monitoring in cardiac arrest: a randomized trial

BackgroundIn-hospital cardiac arrest has a poor prognosis despite active electrocardiography monitoring. The initial rhythm of approximately 25% of in-hospital cardiopulmonary resuscitation (CPR) events is pulseless ventricular tachycardia/ventricular fibrillation (VT/VF). Early defibrillation is an independent predictor of survival in CPR events caused by VT/VF. The automated external cardioverter defibrillator (AECD) is a device attached by pads to the chest wall that monitors, detects, and within seconds, automatically delivers electric countershock to an appropriate tachyarrhythmia.Study Objectives• To evaluate safety of AECD monitoring in hospitalized patients.• To evaluate whether AECDs provide earlier defibrillation than hospital code teams.MethodsThe study is a prospective trial randomizing patients admitted to the telemetry ward to standard CPR (code team) or standard CPR plus AECD monitoring (PowerHeart CRM). The AECD is programmed to deliver one 150 J biphasic shock to patients in sustained VT/VF. Data is collected using the Utstein criteria for cardiac arrest. The primary endpoint is time-to-defibrillation; secondary outcomes include neurological status and survival to discharge, with 3-year follow-up.ResultsTo date, 192 patients have been recruited in the time period between 10/10/2006 to 7/20/2007. A total of 3,655 hours of telemetry data have been analyzed in the AECD arm. The AECD has monitored ambulatory telemetry patients in sinus rhythm, sinus tachycardia, supraventricular tachycardia, atrial flutter or fibrillation, with premature ventricular complexes and non-sustained VT without delivery of inappropriate shocks. One patient experienced sustained VT during AECD monitoring, who was successfully defibrillated (17 seconds after meeting programmed criteria). There are no events to report in the control arm. The patient survived the event without neurological complications. During the same time period, mean time to shock for VT/VF cardiac arrest occurring outside the telemetry ward was 230 ± 50 seconds.ConclusionAECD monitoring is safe and likely results in earlier defibrillation than standard telemetry monitoring.Trial RegistrationNational Institutes of Health registration ID: NCT00382928

Alcohol Intake is Significantly Associated with Atrial Flutter in Patients under 60 Years of Age and a Shorter Right Atrial Effective Refractory Period

Although evidence suggests that alcohol is associated with atrial fibrillation (AF), the association between alcohol and atrial flutter (AFL) has not been examined. The mechanism connecting alcohol and atrial arrhythmias is unknown. Alcohol intake was determined in 195 consecutive patients with AF and AFL. Control subjects included patients with other supraventricular arrhythmias (n = 132) and healthy subjects (n = 54). Because of important competing risk factors for atrial arrhythmias in the elderly, stratification by age was performed. In a subset, atrial effective refractory periods (AERPs) were obtained from the high right atrium and proximal and distal coronary sinus. AF and AFL patients were significantly more likely to be daily alcohol drinkers (27% vs 14% of controls, P = 0.001). In multivariable analysis, AFL patients < or = 60 years of age were significantly more likely to be daily drinkers than to drink no alcohol compared to controls (odds ratio 17, 95% confidence interval 1.6-192.0, P = 0.019). Progressively more frequent alcohol intake was significantly associated with a progressively greater odds of AFL in patients < or = 60 years of age (P = 0.045). Neither AF subjects of any age nor AFL subjects > 60 years of age exhibited significant associations with alcohol after multivariable adjustment. Right AERPs shortened significantly with increasing amounts of alcohol intake (P = 0.025), whereas left AERPs were not associated with alcohol intake. Alcohol intake is positively associated with AFL in younger patients. The mechanism may be related to a shortening of the right AERP.

Clinical and electrophysiological characteristics of patients having atrial flutter with 1:1 atrioventricular conduction

The purpose of this retrospective study was to assess characteristics of patients who had suffered atrial flutter (AFL) with 1:1 atrioventricular (AV) conduction (1:1 AFL). Subjects were 8 patients (61 +/- 14 years) with documented 1:1 AFL, and 101 AFL patients without a history of 1:1 AFL (control patients). 1:1 AFL occurred during physical activity with a ventricular rate of 218 +/- 18 bpm. Antiarrhythmic agents were administered to all eight 1:1 AFL patients, whereas AV nodal conduction-suppressing agents were administered to four. The maximum ventricular rate at which 1:1 AV conduction occurred was significantly lower than when spontaneous 1:1 AFL occurred (164 vs. 218 bpm, P < 0.05). The 1:1 AFL patients had a significantly longer AFL cycle length (CL) (292 vs. 258 ms, P < 0.05) and more rapid AV nodal conduction time (maximum 1:1 AV conduction: 375 vs. 464 ms, P < 0.05) than did control. Arrhythmia had occurred in patients with an AFL CL > or = 250 ms and a CL of maximum 1:1 AV conduction < or = 400 ms. Clinicians should be aware of the potential for 1:1 AV conduction in AFL patients, especially in those with remarkable prolongation of the CL in addition to enhanced AV conduction.

Clinical Efficacy of Bepridil for Class I Antiarrhythmic Drug-Induced Atrial Flutter in Patients with Paroxysmal Atrial Fibrillation

Background: Class I antiarrhythmic drugs can promote the organization of atrial fibrillation (AF) and sometimes converts AF into atrial flutter (AFL) concomitant with difficulty of rate control. We studied the usefulness of Bepridil, which exhibits a class III-like effect, for class I drug-induced AFL in patients with paroxysmal AF. Methods: The study population consisted of 17 consecutive patients (15 men, mean age 65 ± 8 years) with AFL converted from paroxysmal AF following oral treatment of class IA or IC antiarrhythmic agents including pilsicainide (n = 8), cibenzoline (n = 5), flecainide (n = 2), aprindine (n = 1), and propafenone with cibenzoline (n = 1). After the occurrence of AFL, class I drug was replaced by bepridil with a dose of 100–200 mg per day in all patients. Results: After the treatment with bepridil, 15 (88%) out of the 17 patients restored sinus rhythm after 1 to 68 days (average of 21 days). In 12 (80%) of the 15 patients, sinus rhythm was maintained for an average of 23.6 months (range of 1 to 62 months) follow-up period. Although torsade de pointes was not recognized, a marked QT prolongation (0.60 sec) was observed in one patient during the administration of bepridil at a daily dose of 200 mg. In this patient, QT interval was normalized (0.45 sec) after reduction of bepridil to 150 mg daily. Conclusion: Bepridil treatment may be safe and effective for class I drug-induced AFL in patients with paroxysmal AF to restore and maintain sinus rhythm as an alternative therapy for catheter ablation. However, the QT interval must be carefully monitored during this medication.

Emergency Department Use of Intravenous Procainamide for Patients with Acute Atrial Fibrillation or Flutter

Acute atrial fibrillation and flutter are very common arrhythmias seen in emergency department (ED) patients, but there is no consensus for their optimal management. The objective of this study was to examine the efficacy and safety of intravenous (IV) procainamide for acute atrial fibrillation or flutter. This health records review included a consecutive cohort of ED patients with acute-onset atrial fibrillation or atrial flutter who received IV procainamide at one university hospital ED during a five-year period. The standard clinical protocol involved IV infusion of 1 g of procainamide over 60 minutes, followed by electrical cardioversion if necessary. A trained observer extracted data from the original clinical records. Outcome measurements included conversion to sinus rhythm, adverse events, and relapse up to seven days. The 341 study patients had a mean age of 63.9 years (SD +/- 15.5 years), and 56.6% were male. The conversion rates were 52.2% (95% confidence interval = 47% to 58%) for 316 atrial fibrillation cases and 28.0% (95% confidence interval = 13% to 46%) for 25 atrial flutter cases. Mean dose given was 860.7 mg (SD +/- 231.2 mg), and median time to conversion was 55 minutes. Adverse events occurred in 34 cases (10.0%): hypotension, 8.5%; bradycardia, 0.6%; atrioventricular block, 0.6%; and ventricular tachycardia, 0.3%. There were no cases of torsades de pointes, cerebrovascular accident, or death. Most patients (94.4%) were discharged home, but 2.9% of patients returned with a recurrence of atrial fibrillation within seven days. This study of acute atrial fibrillation or flutter patients treated in the ED with IV procainamide suggests that this treatment is safe and effective in this setting. Procainamide should be prospectively compared with other ED strategies.