Atrial Flutter Patients Research Articles

6 Catheter ablation effect on inflammation in atrial flutter patients

6 Catheter ablation effect on inflammation in atrial flutter patients

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

153 Quality of life in typical atrial flutter patients before and after radiofrequency catheter ablation using irrigational and conventional techniques

153 Quality of life in typical atrial flutter patients before and after radiofrequency catheter ablation using irrigational and conventional techniques

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

154 Previous therapy with antiarrhythmics, namely amiodarone, increases the recurrence rate of atrial flutter in successfully ablated isthmus-dependent atrial flutter patients

Mechanism of Atrial Flutter Occurring Late After Orthotopic Heart Transplantation with Atrio‐atrial Anastomosis

We sought to better define the electrophysiologic mechanism of atrial flutter in patients after heart transplantation. Atrial flutter is a recognized problem in the post-cardiac transplant population. The electrophysiologic basis of atrial flutter in this patient population is not completely understood. Six patients with cardiac allografts and symptoms related to recurrent atrial flutter underwent diagnostic electrophysiologic study with electroanatomic mapping and radiofrequency catheter ablation. Comparison was made with a control non-transplant population of 11 patients with typical counterclockwise right atrial flutter. In each case, mapping showed typical counterclockwise activation of the donor-derived portion of the right atrium, with concealed entrainment shown upon pacing in the cavotricuspid isthmus (CTI). The anastomotic suture line of the atrio-atrial anastomosis formed the posterior barrier of the reentrant circuit. Ablation of the electrically active, donor-derived portion of the CTI was sufficient to terminate atrial flutter and render it noninducible. Comparison with the control population showed that the electrically active portion of the CTI was significantly shorter in patients with transplant-associated flutter and that ablation was accomplished with the same or fewer radiofrequency lesions. Atrial flutter in cardiac transplant recipients is a form of typical counterclockwise, isthmus-dependent flutter in which the atrio-atrial anastomotic suture line forms the posterior barrier of the reentrant circuit. Ablation in the donor-derived portion of the CTI is sufficient to create bidirectional conduction block and eliminate this arrhythmia. Ablation or surgical division of the donor CTI at the time of transplantation could prevent this arrhythmia.

Cardioversion of atrial flutter in patients with congenital heart disease: A prospective randomized comparison of biphasic versus monophasic waveforms

Adolescents and young adults with congenital heart disease are at risk for atrial flutter requiring repeated cardioversions. Minimizing the energy needed for successful cardioversion is advantageous. This prospective study was undertaken at 4 institutions to compare the energy required for cardioversion of atrial flutter using monophasic versus biphasic waveforms in a group of 21 patients (pt) (6 females/15 males) who underwent 27 cardioversions after randomization to either a biphasic (Bi), n=14, or monophasic (Mono), n=13, waveform.

The need for atrial flutter ablation following pulmonary vein antrum isolation in patients with and without previous cardiac surgery

The aim of this study was to assess the incidence of atrial flutter (AFL) after pulmonary vein antrum isolation (PVAI) in patients with previous cardiac surgery (PCS) in comparison to patients without PCS and to assess the need for AFL ablation in both groups. Atrial fibrillation (AF) and AFL often co-exist. Pulmonary vein antrum isolation may be sufficient to control both arrhythmias. However, in patients with PCS, atrial incisions, cannulations, and scar areas may cause AFL recurrence despite elimination of pulmonary vein triggers. Data from 1,345 patients who had PVAI were analyzed. Patients with a history of AFL ablation and patients who had concomitant AFL ablation during PVAI were excluded from analysis. Sixty-three patients constituted the PCS group (Group 1, age 57 +/- 13 years, 12 female) and 1,062 patients constituted the non-PCS group (Group 2, age 55 +/- 12 years, 212 female). Patients in Group 1 had larger left atria, higher incidence of AFL pre-PVAI, and lower ejection fraction. There was no significant difference in post-PVAI AF recurrence between Groups 1 and 2, but AFL incidence after PVAI was higher in Group 1 (33% vs. 4%, p < 0.0001). Ablation of AFL in Group 1 patients resulted in an 86% acute success rate and 11% recurrence over a mean follow-up of 357 +/- 201 days. In patients with PCS, post-PVAI AF recurrence is similar to patients without PCS. However, history of PCS is associated with a higher recurrence of AFL after PVAI. In a significant number of patients with PCS, AFL ablation is required to achieve a cure.

Issue Highlights

HomeCirculationVol. 110, No. 8Issue Highlights Free AccessIn BriefPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessIn BriefPDF/EPUBIssue Highlights Originally published24 Aug 2004https://doi.org/10.1161/circ.110.8.893Circulation. 2004;110:893REMODELING OF SINUS NODE FUNCTION IN PATIENTS WITH CONGESTIVE HEART FAILURE: REDUCTION IN SINUS NODE RESERVE, by Sanders et al.Electrophysiological and anatomic remodeling of the ventricles and atrium has been observed previously in patients with congestive heart failure, with atrial remodeling being particularly prominent in those patients with prior atrial fibrillation. The present study by Sanders et al has further defined right atrial abnormalities in patients with congestive heart failure and no prior history of atrial arrhythmias. These investigators found abnormalities both in innervated and pharmacologically denervated sinus node function in marked conduction abnormalities along the crista terminalis. These latter abnormalities were predominately related to markedly abnormal conduction that is consistent with the development of nonuniform anisotropy secondary to fibrosis in that region. These findings provide insight into the increased instance of atrial tachyarrhythmias and, in particular, atrial flutter in patients with heart failure. The anatomic and electrophysiological “barrier” of the crista terminalis is a requisite component of isthmus-dependent flutter. On the basis of the present study, the incidence of atrial fibrillation, as well as the brady-tachy syndrome in patients with congestive heart failure, can be more appropriately understood. See p 897.LEFT VENTRICULAR ASSIST DEVICE AS DESTINATION FOR PATIENTS UNDERGOING INTRAVENOUS INOTROPIC THERAPY: A SUBSET ANALYSIS FROM REMATCH (RANDOMIZED EVALUATION OF MECHANICAL ASSISTANCE IN TREATMENT OF CHRONIC HEART FAILURE), by Stevenson et al.There has been intense interest in the use of left ventricular assist devices (LVADs) as long-term destination therapy for patients with end-stage heart failure. Although the Randomized Evaluation of Mechanical Assistance in Treatment of Chronic Heart Failure (REMATCH) trial found that the use of LVADs extended survival, the absolute increment was modest. In a subset analysis of the REMATCH trial, Stevenson et al report that patients who required intravenous inotropic support at baseline had a worse prognosis with standard care than patients who did not require inotropic support, but with LVADs, both groups obtained a similar survival rate. As a result, the incremental survival benefit with LVAD was greater in patients who required inotropic support, thus identifying a subpopulation that may particularly benefit from LVAD therapy. See p 975.RELATIONSHIP BETWEEN ACTIVATED CLOTTING TIME AND ISCHEMIC OR HEMORRHAGIC COMPLICATIONS: ANALYSIS OF 4 RECENT RANDOMIZED CLINICAL TRIALS OF PERCUTANEOUS CORONARY INTERVENTION, by Brener et al.In patients undergoing coronary interventions, unfractionated heparin is monitored by the activated clotting time (ACT). The ACT that predicts both hemorrhagic complications and coronary ischemia is not known, particularly in the era of multiple platelet inhibitor use. Brener and colleagues pooled the results from 4 large studies comprising >8000 patients and found that the ACT did not correlate with ischemic complications and had a minimal association with bleeding. Increased weight-adjusted heparin dose was associated with a modest increase in rate of bleeding. Although the results would need to be validated in a prospective trial, this study suggests that the ACT provides little helpful information beyond the heparin dose. See p 994.Visit www.circ.ahajournals.org:Images in Cardiovascular MedicineLeriche Syndrome Visualized by 3-Dimensional Multislice Computed Tomography Angiography. See p e77. Download figureDownload PowerPoint Previous Back to top Next FiguresReferencesRelatedDetails August 24, 2004Vol 110, Issue 8 Advertisement Article InformationMetrics https://doi.org/10.1161/circ.110.8.893 Originally publishedAugust 24, 2004 PDF download Advertisement

Prolonged Activation of Hemostatic Markers Following Conversion of Atrial Flutter to Sinus Rhythm

It remains controversial whether prophylactic anticoagulation for embolism is required in patients with atrial flutter (AFL) prior to and following cardioversion as in patients with atrial fibrillation. To evaluate the potential prothrombotic state following cardioversion of AFL, concentrations of hemostatic markers were determined before and after conversion to sinus rhythm (SR). In 12 patients (mean age 68 years) with AFL who underwent transesophageal echocardiography in the plasma concentrations of markers for platelet activity (platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG)), thrombotic status (thrombin-antithrombin III complex (TAT) and prothrombin fragments 1 and 2 (F1+2)) and fibrinolytic status (D-dimer and plasmin-alpha(2)-plasmin inhibitor complex (PIC)) were determined during AFL, and 3 days and 7 days after restoration of SR. Left atrial appendage (LAA) blood flow velocity was lower immediately after than before restoration of SR (29+/-11 vs 41+/-23 cm/s, p<0.05). Three patients developed left atrial spontaneous echo contrast immediately after restoration of SR. Although the concentrations of the markers of platelet activity did not change after restoration of SR, those of TAT and PIC increased 7 days after restoration of SR as compared with during AFL (p<0.05). AFL patients have a potential risk for thromboembolism after restoration of SR and therefore anticoagulation might be required in selected patients.

A23-6 Radiofrequency ablation of atrial flutter in patients with atrial fibrillation treated with propafenone or amiodarone

A23-6 Radiofrequency ablation of atrial flutter in patients with atrial fibrillation treated with propafenone or amiodarone

A23-6 Radiofrequency ablation of atrial flutter in patients with atrial fibrillation treated with propafenone or amiodarone

A23-6 Radiofrequency ablation of atrial flutter in patients with atrial fibrillation treated with propafenone or amiodarone

Left Atrial Appendage Function and Abnormal Hypercoagulability in Patients With Atrial Flutter

The prevalence of thromboembolism might be higher than previously recognized in patients with atrial flutter (AFL) based on findings of transesophageal echocardiography (TEE). To evaluate the potential prothrombotic state in patients with AFL, TEE findings and hemostatic markers were compared among patient groups with AFL, normal sinus rhythm (NSR) and chronic nonvalvular atrial fibrillation (AF). Cross-sectional study at a university hospital. In 28 patients (mean age, 63 years) with AFL, 58 patients (mean age, 66 years) with AF, and 27 patients (mean age, 61 years) with NSR who underwent TEE, plasma levels of markers for platelet activity (platelet factor 4 and beta-thromboglobulin [beta-TG]), thrombotic status (thrombin-antithrombin III complex and prothrombin fragments 1 and 2) and fibrinolytic status (d-dimer and plasmin-alpha(2)-plasmin inhibitor complex) were determined. Left atrial appendage (LAA) blood flow velocity in patients with AFL was higher (p < 0.05) than that in patients with AF, but was lower (p < 0.05) than that in patients with NSR (AF, 25 +/- 2; AFL, 44 +/- 4; NSR, 60 +/- 4 cm/s). Dense left atrial spontaneous echo contrast (SEC) was found in 4 patients (14%) with AFL and 16 patients (28%) with AF. There was no significant difference in plasma levels of hemostatic markers between the AFL group and the NSR group. AFL patients with impaired LAA function (LAA flow < 30cm/s, dense SEC, or both), however, showed higher level of d-dimer and beta-TG than those without impaired LAA function (d-dimer, 1.9 +/- 0.6 microg/mL vs 0.4 +/- 0.1 microg/mL; beta-TG, 73 +/- 17 ng/mL vs 33 +/- 5 ng/mL, p < 0.05). Patients with AFL as a whole are not in the prothrombotic state as compared with those with AF. However, patients with AFL and impaired LAA function are at potentially high risk for thromboembolism and might require anticoagulation.

Safety and efficacy of radiofrequency ablation of common atrial flutter in elderly patients: a single center prospective study.

Little data is available concerning the invasive treatment of atrial flutter (AFL) in elderly patients. The purpose of this prospective study was to evaluate the risks, safety, and follow-up of radiofrequency (RF) catheter ablation of common AFL in patients >75 years old (n = 61) (Group I) compared to patients younger than 75 years (n = 187) (Group II). The study population consisted of 248 patients (81% men/19% women), 21 to 96 years old (mean 66.3 +/- 12 years) with AFL, referred for RF from June 1999 to June 2001. RF endpoint was the assessment of the bidirectional block. The cumulative risk of atrial fibrillation (AF) was analyzed by the Kaplan-Meier method and log-rank test. The mean follow-up was 12.4 +/- 9 months. No complication occurred. Group I (80.1 +/- 4.5 years) did not differ significantly from Group II (61 +/- 11 years) regarding: AF history before ablation (34.4% vs 39.8%), structural heart disease (54% vs 42%), LVEF (57%+/- 12% vs 58%+/- 12%), left atrial size (43.8 +/- 7 vs 42.5 +/- 7), cava-tricuspid isthmus dimension (40 +/- 10 vs 39 +/- 4 mm), bidirectional block (100% vs 96.2%), RF application (12.5 +/- 10 vs 13.5 +/- 12 minutes), AFL recurrence (3.3% vs 5.3%), antiarrhythmic agents at hospital discharge (34.4% vs 38.9%), mean follow-up (12 +/- 9 vs 13 +/- 9 months) and AF occurrence (29.5% vs 20.3%; P = 0.2). Of these, the incidence of AF in patients without prior history (n = 150) was 7 (18%) of 39 for Group I and 11 (10%) of 111 for Group II (P = 0.1) after follow-up. Catheter ablation of AFL in very elderly patients appears to be a reasonable approach regarding feasibility, effectiveness, and low procedural risk.

Irrigated-tip versus 8-mm-tip catheter for radiofrequency ablation of common atrial flutter in patients with cavo-tricuspid isthmus lengths > 35 mm: Is the catheter selection or the cavo-tricuspid anatomy a determinant factor for atrial flutter ablation?

Irrigated-tip versus 8-mm-tip catheter for radiofrequency ablation of common atrial flutter in patients with cavo-tricuspid isthmus lengths > 35 mm: Is the catheter selection or the cavo-tricuspid anatomy a determinant factor for atrial flutter ablation?

Three-dimensional noncontact mapping defines two zones of slow conduction in the circuit of typical atrial flutter.

The cavotricuspid isthmus (CTI) is a slow conduction area in the circuit of typical atrial flutter. However, conventional methods are limited by the inaccuracy of measurements of distance on the surface of the heart. The aim of the study was to define the conduction properties of the atrial flutter circuit along the tricuspid annulus by using a three-dimensional noncontact mapping system. In 34 atrial flutter patients (30 men, 4 women; mean age 54 +/- 14; 27 counter-clockwise, 4 clockwise, and 3 both), a noncontact multielectrode array was used to reconstruct electrograms in the right atrium. Isochronal and isopotential propagation mapping was performed during atrial flutter. The conduction velocity was calculated by dividing conduction time by surface distance. The right atrium along the tricuspid annulus was divided into five regions: lateral wall, superior right atrium, septum, septal CTI, and lateral CTI. Conduction velocities were 0.99 +/- 0.85, 1.67 +/- 1.21, 1.58 +/- 1.05, 0.82 +/- 0.72, and 1.68 +/- 1.00 m/s in counter-clockwise and 0.81 +/- 0.71, 2.61 +/- 1.90, 1.52 +/- 0.91, 0.91 +/- 0.80 and 1.91 +/- 0.83 m/s in clockwise, respectively. Conduction velocities were significantly slower in the septal CTI and lateral wall than in the lateral CTI, the septum, and the superior right atrium (P < 0.05). No significant difference was found between the septal CTI and the lateral wall. Conduction within the septal CTI was slower in patients treated with antiarrhythmic agents than in untreated patients (P < 0.05). The septal part of the CTI (but not the lateral CTI) and the lateral wall are slow conduction zones in the atrial flutter circuit, and both may, therefore, be mechanically important for the development of atrial flutter.

Relationship between polarity of the flutter wave in the surface ECG and endocardial atrial activation sequence in patients with typical counterclockwise and clockwise atrial flutter.

The relation between ECG and activation patterns within atria in typical atrial flutter (AFL) patients (pts) has not been defined due to the lack of simultaneous multisite right and left atrial mapping. In 13 pts with AFL, a Halo catheter was positioned along tricuspid annulus and multipolar catheters were placed in right atrial appendage, His bundle region, coronary sinus (CS), proximal portion of right pulmonary artery (Bachmann's bundle region, BB) and esophagus (Eso) to record right and left atrial activation simultaneously. In counterclockwise (CCW) AFL (11 pts), 9 showed negative flutter wave (F) and 2 positive F in the inferior leads. CCW/negative F; CS electrograms (EGs) were proximal to distal, Eso EGs were inferior to superior and BB activation was later than CS and Eso. positive F; BB activation was earlier than CS. Eso EGs were superior to inferior or simultaneous. In clockwise (CW) AFL (7 pts), 5 showed positive F and 2 negative F. CW/positive F; BB activation preceded Eso and CS. Eso EGs were superior to inferior. CS EGs were proximal to distal (1), middle to proximal, distal (3) or proximal, distal to middle (1). negative F; CS EGs were proximal to distal. CS activation was earlier than BB or CS and BB activation were simultaneous. Eso EGs were inferior to superior. Impulse conduction to the left atrial free wall through either lower or upper interatrial connection is a major determinant of ECG morphology in AFL.

Prospective evaluation of catheter ablation in patients with implantable cardioverter defibrillators and multiple inappropriate ICD therapies due to atrial fibrillation and type I atrial flutter.

The high incidence of inappropriate therapies due to drug refractory supraventricular tachycardia remains a major unsolved problem of the ICD. Most of the inappropriate therapies for supraventricular tachycardia are caused by AF and type I atrial flutter with rapid ventricular response. The purpose of this prospective study was to determine the usefulness of AVN modulation or ablation for rapid AF and ablation of the tricuspid annulus-inferior vena cava (TA-IVC) isthmus for type I atrial flutter in ICD patients with frequent inappropriate ICD interventions. Eighteen consecutive patients were enrolled in this study. Twelve patients received a mean of 34 +/- 36 antitachycardia pacing (ATP) and 41 +/- 32 shock therapies for rapid AF during 49 +/- 39 months, and 6 patients a mean of 111 +/- 200 ATP and 11 +/- 8 shock therapies for type I atrial flutter during 52 +/- 37 months preceding ablation procedure. Modification of the AVN was successful in 10 (83%) of 12 AF patients, in 2 (17%) patients ablation of the AVN was performed. A complete TA-IVC isthmus block was achieved in 5 (83%) of 6 atrial flutter patients. Three (25%) AF patients had 11 +/- 24 recurrences of ATP and 0.4 +/- 1.1 shock therapies for rapid AF during 15 +/- 7 months. None of the atrial flutter patients had recurrences of inappropriate therapies for type I atrial flutter during 14 +/- 8 months, but two (33%) patients had inappropriate ICD therapies for type II atrial flutter or rapid AF. There was an overall mean incidence of 18 +/- 22 inappropriate ICD therapies per 6 months before and 4 +/- 9 per 6 months after the ablation procedure (P < 0.05). In conclusion, radiofrequency catheter modification or ablation of the AVN for rapid AF and ablation for atrial flutter type I are demonstrated to be highly effective in the majority of ICD patients with drug refractory multiple inappropriate ICD therapies.

Response to flecainide infusion predicts long-term success of hybrid pharmacologic and ablation therapy in patients with atrial fibrillation

OBJECTIVESWe tested the hypothesis that the response to flecainide infusion can identify patients with atrial fibrillation (AF) in whom the hybrid pharmacologic and ablation therapy reduces the recurrences of AF.BACKGROUNDInfusion of class IC anti-arrhythmic drugs may promote transformation of AF into atrial flutter. Catheter ablation of atrial flutter has been demonstrated to be highly effective in preventing recurrences of atrial flutter.METHODSSeventy-one consecutive patients with paroxysmal or chronic AF, in whom flecainide infusion (2 mg/kg body weight, intravenously) determined the transformation of AF into common atrial flutter (positive response), were randomized to receive one of the following treatments: oral pharmacologic treatment with flecainide (group A, n = 23); the hybrid treatment (catheter ablation of the inferior vena cava-tricuspid annulus isthmus, plus oral flecainide) (group B, n = 24); or catheter ablation of the isthmus only (group C, n = 24). Thirty-seven patients with a negative response to flecainide, who chose to be submitted to the hybrid treatment, were selected as the control group (group D).RESULTSDuring a mean follow-up period of 24 ± 7.2 months, the recurrences of AF and atrial flutter in group B (42%) were significantly lower than those in group A (78%, p < 0.001), group C (92%, p < 0.001) and group D (92%, p < 0.001).CONCLUSIONSThe creation of a complete bi-directional conduction block at the inferior vena cava-tricuspid annulus isthmus, plus flecainide administration, reduces the recurrences of both AF and atrial flutter in patients with class IC atrial flutter. Moreover, the early response to flecainide is safe and reliable in identifying patients who may benefit from this therapy.

Atrial and ventricular electromechanical function in 1-ventricle hearts: Influence of atrial flutter and Fontan procedure

Objective: Echocardiography was used to study electromechanical atrial and ventricular function in adult patients with a 1-ventricle heart who were in sinus rhythm to better understand the recurrence of atrial flutter in these conditions. Patients who had recent atrial flutter, with and without the Fontan procedure, were compared with those who had no arrhythmia. Methods: This was a prospective study that used M-mode and 2-dimensional Doppler echocardiography and electrocardiography. Conventional measurements were used to evaluate ventricular long-axis function. Basic data were drawn from case notes. The setting was a designated quaternary service for grown-up congenital heart patients (GUCH) in a tertiary referral center for cardiology and cardiac surgery. From January 1997 to February 1998, 26 consecutive adult patients (aged >16 years) with a heart with one functioning ventricle and a history of atrial flutter were studied: group 1, with non-Fontan palliative surgery or no surgery (10 patients), and group 2, with Fontan-type repair (16 patients). Also studied were 20 patients with a 1-ventricle heart but no history of atrial flutter. These 20 patients were divided into 2 groups: control 1, which comprised 14 patients with previous shunts or no surgery, and control 2, which consisted of 6 patients with Fontan repair. Results: P-wave duration on the electrocardiogram was similar in the 4 patient groups, but the amplitude was reduced in group 2 and control 2 (patients with Fontan surgery) (P <.016). Bifid P wave was seen in 5 (50%) of 10 patients in group 1 and in 6 (43%) of 14 patients in control 1, but it was not seen in patients with Fontan (P <.01). Ventricular systolic and diastolic dimensions and fractional shortening were not different between patients and controls. Right atrial transverse dimensions were greater in group 2 patients compared with those in controls. Significant atrioventricular valve regurgitation was seen in 9 of 10 group 1 patients but in none of the others. Right-sided total long-axis excursion and atrial A-wave amplitude were depressed in group 2 patients compared with the values in the others. The onset of right atrial shortening was delayed by 50 ms in group 2 compared with control 2, whereas the left atrial shortening was delayed by 30 ms in group 1 compared with control 1. This particular disturbance remained 6 months after cardioversion. Conclusion: In 1-ventricle hearts, significant atrioventricular valve regurgitation is commonly associated with atrial flutter in patients who did not undergo the Fontan procedure, and with electromechanical disturbances in those who did. Recognition of disturbances in ventricular long-axis function may thus assist in the identification of patients with a 1-ventricle heart who are prone to atrial flutter. (J Am Soc Echocardiogr 2001;14:186-93.)

Syncope in patients with atrial flutter during treatment with class Ic antiarrhythmic drugs

We describe 2 atrial flutter (AFL) patients with syncope during treatment with class Ic antiarrhythmic drugs. During the syncope, 1:1 atrioventricular (AV) conduction during AFL preceded a wide QRS tachycardia. The class Ic drugs, flecainide and pilsicainide, slowed the atrial rate, resulting in AFL with 1:1 AV conduction, and the width of the QRS complexes became wider during the tachycardia. Syncope was abolished after successful radiofrequency catheter ablation of the AFL. These potential proarrhythmic effects of the class Ic drugs should be taken into account in AFL patients, and concomitant use of β-blocking agents would be critical to prevent proarrhythmias.