Risk of thromboembolism in chronic atrial flutter

Differences in Stroke or Systemic Thromboembolism Readmission Risk After Hospitalization for Atrial Fibrillation and Atrial Flutter

Background

Although atrial fibrillation (AF) and atrial flutter (AFL) are different arrhythmias, they are assumed to confer the same risk of stroke and systemic thromboembolism (STE) despite a lack of available evidence. In this study, we investigated the difference in the risk of stroke or STE after AF and AFL hospitalizations.

Methodology

The National Readmission Database (NRD) 2018 was used to identify AF and AFL patients using appropriate International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes and were followed until the end of the calendar year to identify stroke or STE readmissions. Survival estimates were calculated, and a Cox proportional hazards model was used to calculate the adjusted hazards ratio (aHR) and compare the risk of stroke or STE readmissions between AF and AFL groups.

Results

A total of 215,810 AF and 15,292 AFL patients were identified. AFL patients were more likely to be younger (66 vs. 70 years), male (68% vs. 47%), and had higher prevalence of obesity (25% vs. 22%), obstructive sleep apnea (14% vs. 12%), diabetes mellitus (31% vs. 26%), and alcohol use (6.9% vs. 5.5%) (all p < 0.01). After adjusting for potential patient and hospital-level characteristics, there was a statistically significant decrease in one-year stroke or STE readmission risk in AFL patients compared to AF patients (aHR 0.79 (0.66-0.95); p = 0.01).

Conclusions

AFL patients are commonly younger males with a higher burden of medical comorbidity. There is a decrease in the one-year risk of stroke or STE events in AFL patients compared to AF. The predictors of stroke and STE are similar in both AFL and AF groups. Further studies with longer follow-up and anticoagulation data are needed to verify the results.

EACVI recommendations on cardiovascular imaging for the detection of embolic sources: endorsed by the Canadian Society of Echocardiography

Cardioaortic embolism to the brain accounts for approximately 15-30% of ischaemic strokes and is often referred to as 'cardioembolic stroke'. One-quarter of patients have more than one cardiac source of embolism and 15% have significant cerebrovascular atherosclerosis. After a careful work-up, up to 30% of ischaemic strokes remain 'cryptogenic', recently redefined as 'embolic strokes of undetermined source'. The diagnosis of cardioembolic stroke remains difficult because a potential cardiac source of embolism does not establish the stroke mechanism. The role of cardiac imaging-transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE), cardiac computed tomography (CT), and magnetic resonance imaging (MRI)-in the diagnosis of potential cardiac sources of embolism, and for therapeutic guidance, is reviewed in these recommendations. Contrast TTE/TOE is highly accurate for detecting left atrial appendage thrombosis in patients with atrial fibrillation, valvular and prosthesis vegetations and thrombosis, aortic arch atheroma, patent foramen ovale, atrial septal defect, and intracardiac tumours. Both CT and MRI are highly accurate for detecting cavity thrombosis, intracardiac tumours, and valvular prosthesis thrombosis. Thus, CT and cardiac magnetic resonance should be considered in addition to TTE and TOE in the detection of a cardiac source of embolism. We propose a diagnostic algorithm where vascular imaging and contrast TTE/TOE are considered the first-line tool in the search for a cardiac source of embolism. CT and MRI are considered as alternative and complementary tools, and their indications are described on a case-by-case approach.

Trend and risk factors of recurrence and complications after arrhythmias radiofrequency catheter ablation: a nation-wide observational study in Taiwan

OBJECTIVES

This study determined the recurrence and complication rates after radiofrequency catheter ablation (RFCA) for those with paroxysmal supraventricular tachycardia (PSVT), Wolff-Parkinson-White syndrome (WPW), atrial flutter (AFL), atrial fibrillation (AF) and ventricular tachycardia (VT).

STUDY DESIGN AND SETTING

This retrospective study included RFCAs for 2001-2010 in the Taiwan National Health Insurance Research Database. Primary outcomes included perioperative complications (pericardial effusion and new-onset stroke), RFCA recurrence and long-term outcomes (high-grade atrioventricular block (AVB) and pacemaker implantation).

RESULTS

Of 19,475 patients who underwent RFCA, prevalence rates were 56.7% for PSVT, 13.5% for WPW, 9.5% for AFL, 5.1% for AF and 2.7% for VT. Prevalence rates increased in AF, AFL and VT over the study years. During an average follow-up period of 4.3 years (SD: 2.8 years), recurrence rates for PSVT, WPW, VT, AFL and AF were 2.0%, 4.9%, 5.7%, 5.8% and 16.1%, respectively. Compared with the PSVT group, the WPW and AF groups had significantly higher risk of pericardial effusion during admission (adjusted OR (aOR) 2.98, 95% CI (CI) 1.24 to 7.15; aOR 4.09, 95% CI 1.90 to 8.79, respectively); the AFL group had a higher risk of new-onset stroke during admission (aOR 4.07, 95% CI 1.39 to 11.91); the WPW group had a lower risk of high-grade AVB during follow-up (adjusted HR (aHR) 0.37, 95% CI 0.19 to 0.71) while the AFL group had a greater risk (aHR 1.74, 95% CI 1.17 to 2.60); and the AFL group had a higher risk of permanent pacemaker (aHR 2.14, 95% CI 1.27 to 3.62).

CONCLUSIONS

The RFCA rate increased rapidly during 2001-2010 for AF, AFL and VT. Recurrence was associated with congenital heart disease in PSVT and WPW, and with age in AF and AFL. AFL had a higher risk of permanent pacemaker implantation and new stroke. AF had a higher risk of life-threatening pericardial effusion.

CHA₂DS₂-VASc Score in the Prediction of Ischemic Stroke in Patients after Radiofrequency Catheter Ablation of Typical Atrial Flutter

PURPOSE

Despite undergoing successful catheter ablation of typical atrial flutter (AFL), patients remain at increased risk for ischemic stroke. However, data on risk prediction tools for the development of stroke after AFL ablation are lacking. This study investigates whether CHA₂DS₂-VASc score is useful for predicting ischemic stroke after successful ablation of typical AFL.

MATERIALS AND METHODS

A total of 293 patients (236 men, mean age 56.1±13.5 years) who underwent successful radiofrequency catheter ablation for typical AFL were included in this study. The clinical end point was occurrence of ischemic stroke during follow-up after AFL ablation.

RESULTS

During the follow-up period (60.8±45.9 months), ischemic stroke occurred in 18 (6%) patients at a median of 34 months (interquartile range, 13-65 months). CHA₂DS₂-VASc score [hazard ratio 2.104; 95% confidence interval (CI), 1.624-2.726; p<0.001] was an independent predictor for the occurrence of stroke after AFL ablation. The area under the receiver operating characteristic curve for CHA₂DS₂-VASc score was 0.798 (95% CI, 0.691-0.904). The CHA₂DS₂-VASc score could be used to stratify patients into two groups with different incidences of ischemic stroke (1.6% vs. 14.4%, p<0.001) at a cutoff value of 2.

CONCLUSION

CHA₂DS₂-VASc score is useful in a prediction model for the risk of stroke after catheter ablation of typical AFL.

Atrial Flutter, Typical and Atypical: A Review

Clinical electrophysiology has made the traditional classification of rapid atrial rhythms into flutter and tachycardia of little clinical use. Electrophysiological studies have defined multiple mechanisms of tachycardia, both re-entrant and focal, with varying ECG morphologies and rates, authenticated by the results of catheter ablation of the focal triggers or critical isthmuses of re-entry circuits. In patients without a history of heart disease, cardiac surgery or catheter ablation, typical flutter ECG remains predictive of a right atrial re-entry circuit dependent on the inferior vena cava-tricuspid isthmus that can be very effectively treated by ablation, although late incidence of atrial fibrillation remains a problem. Secondary prevention, based on the treatment of associated atrial fibrillation risk factors, is emerging as a therapeutic option. In patients subjected to cardiac surgery or catheter ablation for the treatment of atrial fibrillation or showing atypical ECG patterns, macro-re-entrant and focal tachycardia mechanisms can be very complex and electrophysiological studies are necessary to guide ablation treatment in poorly tolerated cases.

Do Different Atrial Flutter Types Carry the Same Thromboembolic Risk?

Thromboembolic risk of atrial flutter (AFl) types has not been elucidated sufficiently in previous reports. The authors classified the patients according to surface electrocardiogram and electrophysiologic characteristics as those with typical AFl (37 patients, 78.4% male, mean age 59.8 ±9.5 years) and atypical AFl (13 patients, 69.2% male, mean age 60.9 ±6.9 years) and compared them regarding some clinical, echocardiographic, and hematologic parameters. An age- and gender-matched control group composed of 20 individuals without any organic heart disease in sinus rhythm was chosen (80% male, mean age 60.3 ±7.9 years). Clinical features such as age, gender, organic heart disease, hypertension, diabetes mellitus, AFl duration, and the prevalence of paroxysmal atrial fibrillation were similar in both AFl groups. Echocardiographic parameters such as left ventricular ejection fraction, left atrial (LA) diameter, LA spontaneous echo contrast, and LA appendage emptying velocities were similar in both AFl groups. Fibrinogen, fibrin D-dimer, and thrombin-antithrombin III levels reflecting coagulation system activity were found to be increased in the patients with atypical AFl when compared with those with typical AFl and the control group (p<0.001). In Pearson’s correlation analysis, significant correlation between these hematologic markers and clinical and echocardiographic parameters were not found (p>0.05). The coagulation system activity was found to be increased in patients with atypical AFl. Thus, anticoagulation due to the increased thromboembolic risk should be considered in patients with atypical AFl.

Diagnostic Performance of a Smartphone-Based Photoplethysmographic Application for Atrial Fibrillation Screening in a Primary Care Setting

Background

Diagnosing atrial fibrillation (AF) before ischemic stroke occurs is a priority for stroke prevention in AF. Smartphone camera–based photoplethysmographic (PPG) pulse waveform measurement discriminates between different heart rhythms, but its ability to diagnose AF in real‐world situations has not been adequately investigated. We sought to assess the diagnostic performance of a standalone smartphone PPG application, Cardiio Rhythm, for AF screening in primary care setting.

Methods and Results

Patients with hypertension, with diabetes mellitus, and/or aged ≥65 years were recruited. A single‐lead ECG was recorded by using the AliveCor heart monitor with tracings reviewed subsequently by 2 cardiologists to provide the reference standard. PPG measurements were performed by using the Cardiio Rhythm smartphone application. AF was diagnosed in 28 (2.76%) of 1013 participants. The diagnostic sensitivity of the Cardiio Rhythm for AF detection was 92.9% (95% CI] 77–99%) and was higher than that of the AliveCor automated algorithm (71.4% [95% CI 51–87%]). The specificities of Cardiio Rhythm and the AliveCor automated algorithm were comparable (97.7% [95% CI: 97–99%] versus 99.4% [95% CI 99–100%]). The positive predictive value of the Cardiio Rhythm was lower than that of the AliveCor automated algorithm (53.1% [95% CI 38–67%] versus 76.9% [95% CI 56–91%]); both had a very high negative predictive value (99.8% [95% CI 99–100%] versus 99.2% [95% CI 98–100%]).

Conclusions

The Cardiio Rhythm smartphone PPG application provides an accurate and reliable means to detect AF in patients at risk of developing AF and has the potential to enable population‐based screening for AF.

Stroke and Systemic Embolism After Successful Ablation of Typical Atrial Flutter

BACKGROUND

Following successful cavotricuspid isthmus (CTI) ablation during typical atrial flutter (AFL), anticoagulation therapy is usually withdrawn. However, potential subsequent atrial fibrillation (AF) in these patients may increase embolic risk in the long term. Embolic rates in this setting have not been clearly established. Our aim was to determine the incidence of stroke/systemic embolism following radiofrequency ablation of AFL, particularly in those without a prior history of AF.

HYPOTHESIS

After succesful AFL ablation, patients may suffer embolic complications in the long-term follow-up, mainly due to asymptomatic AF episodes.

METHODS

We conducted a retrospective analysis of all patients who underwent CTI ablation due to AFL in our center between 2006 and 2009.

RESULTS

During the study period, 188 patients (mean age, 62.9 ± 8.6 years) underwent CTI ablation; 120 without prior AF were included in the study. At the end of the follow-up period (mean, 5.0 ± 2.4 years), 56.7% of patients (68/120) remained in sinus rhythm, 7/120 experienced a recurrence of AFL, and 45/120 (38%) developed AF. Ischemic stroke occurred in 11 patients and systemic embolism in 1. Of these patients, 5 had documented AF following AFL ablation. In the remaining 7 cases, previously undiagnosed AF was subsequently diagnosed at the time of stroke/embolism.

CONCLUSIONS

Patients with AFL who undergo successful ablation are by no means free from embolic complications during long-term follow-up, mainly due to a high rate of AF development. Given the difficulties in detecting AF and the uncertainty about the temporal relation of AF and stroke, oral anticoagulation may need to be continued in those patients with underlying stroke risk factors.

Executive Summary: European Heart Rhythm Association Consensus Document on the Management of Supraventricular Arrhythmias: Endorsed by Heart Rhythm Society (HRS), Asia-Pacific Heart Rhythm Society (APHRS), and Sociedad Latinoamericana de Estimulación Cardiaca y Electrofisiologia (SOLAECE)

This paper is an executive summary of the full European Heart Rhythm Association (EHRA) consensus document on the management of supraventricular arrhythmias, published in Europace. It summarises developments in the field and provides recommendations for patient management, with particular emphasis on new advances since the previous European Society of Cardiology guidelines. The EHRA consensus document is available to read in full at http://europace.oxfordjournals.org.

Arrhythmias (IV). Clinical approach to atrial tachycardia and atrial flutter from an understanding of the mechanisms. Electrophysiology based on anatomy

In 2009, 2343 catheter ablation procedures were performed in Spain for focal atrial tachycardia or atrial flutter (typical and atypical), with a yearly growth rate of 8%, indicating the clinical importance of these arrhythmias. The classic categorization of atrial tachycardia and atrial flutter based on rate and morphological criteria has become almost irrelevant at a time when clinical electrophysiology may lead to curative intervention based on a definition of the mechanism, making it necessary to bring laboratory experience closer to clinical practice. In this review we outline our present understanding of atrial tachycardia mechanisms, both focal and macroreentrant, and attempt to establish the conceptual links with classic concepts that may help the clinician to make a differential diagnosis and establish therapeutic indications, including that of an electrophysiologic study. Some of the concepts may seem complex, but we thought it important to provide an overview of the electrophysiological methods that may eventually lead to the description of the anatomic bases of the arrhythmias; currently, these are easier to understand thanks to the virtual anatomic casts built using computerized navigation systems.

Comparison of antero-lateral versus antero-posterior electrode position for biphasic external cardioversion of atrial flutter

External cardioversion is an established and very important tool to terminate symptomatic atrial flutter. The superiority of the biphasic waveform has been demonstrated for atrial flutter, but whether electrode position affects the efficacy of cardioversion in this population is not known. The aim of this trial was to evaluate whether anterior-lateral (A-L) compared with anterior-posterior (A-P) electrode position improves cardioversion results. Of 130 screened patients, 96 (72 men, mean age 62 +/- 12 years) were included and randomly assigned to a cardioversion protocol with either A-L or A-P electrode position. In each group, 48 patients received sequential biphasic waveform shocks using a step-up protocol consisting of 50, 75, 100, 150, or 200 J. The mean energy (65 +/- 13 J for A-L vs 77 +/- 13 J for A-P, p = 0.001) and mean number of shocks (1.48 +/- 1.01 for A-L vs 1.96 +/- 1.00 for A-P, p = 0.001) required for successful cardioversion were significantly lower in the A-L group. The efficacy of the first shock with 50 J in the A-L electrode position (35 of 48 patients [73%]) was also highly significantly greater than the first shock with 50 J in the A-P electrode position (18 of 48 patients [36%]) (p = 0.001). In conclusion, the A-L electrode position increases efficacy and requires fewer energy and shocks in external electrical cardioversion of common atrial flutter. Therefore, A-L electrode positioning should be recommended for the external cardioversion of common atrial flutter.

Supraventricular Dysrhythmias

Cardiovascular nursing practice includes accountability for the clinical and organizational processes to ensure positive outcomes for patients having cardiac dysrhythmias. For patients with supraventricular dysrhythmias, nurses have studied patient outcomes related to mortality, morbidity, quality of life, psychological and physical functioning, and symptoms. Nurses have also explored these same outcomes associated with the management of supraventricular dysrhythmias. In addition, nurses have contributed to understanding organizational outcomes such as healthcare utilization and costs associated with these patients. For patients with atrial fibrillation after cardiac surgery, nurses have studied patient and organizational outcomes related to mortality, morbidity, symptoms, psychological and physical functioning, and economic outcomes. This research has included numerous interdisciplinary studies, and most of it has been descriptive or observational in design. Areas for future nursing outcomes research, including more interventional studies, are discussed.

Catheter ablation of atrial fibrillation

Following the advent of the surgical maze procedure, several catheter techniques have been developed to provide permanent prophylaxis against atrial fibrillation. These noninvasive techniques work by compartmentalizing the atria, by ablating the arrhythmogenic foci, or by isolating the atria from these foci. Although still at an early stage of development, preliminary results using focal ablation and circumferential ablation show extreme promise.

Role of electrophysiological study and ablation in the management of recurrent atrial flutter associated with haemodynamic compromise in a critically ill patient

Atrial flutter is a common arrhythmia. In the critical care setting, the arrhythmia may present in any patient, but it is most commonly seen in patients with impaired ventricular function, valvular disease, atrial dilatation or after cardiac surgery. We present a 68-year-old lady with recurrent poorly tolerated atrial flutter that was resistant to multiple pharmacological interventions and complicated by cardiogenic shock following direct current cardioversion. The flutter was successfully cured with radiofrequency ablation and was followed by an immediate improvement in her haemodynamic status. We review the management of acute atrial flutter and discuss the role of electrophysiologically guided ablation.

Antithrombotic Therapy in Atrial Fibrillation

This chapter about antithrombotic therapy in atrial fibrillation (AF) is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following (all vitamin K antagonist [VKA] recommendations have a target international normalized ratio [INR] of 2.5; range, 2.0 to 3.0): In patients with persistent or paroxysmal AF (PAF) [intermittent AF] at high risk of stroke (ie, having any of the following features: prior ischemic stroke, transient ischemic attack, or systemic embolism, age > 75 years, moderately or severely impaired left ventricular systolic function and/or congestive heart failure, history of hypertension, or diabetes mellitus), we recommend anticoagulation with an oral VKA, such as warfarin (Grade 1A). In patients with persistent AF or PAF, age 65 to 75 years, in the absence of other risk factors, we recommend antithrombotic therapy with either an oral VKA or aspirin, 325 mg/d, in this group of patients who are at intermediate risk of stroke (Grade 1A). In patients with persistent AF or PAF < 65 years old and with no other risk factors, we recommend aspirin, 325 mg/d (Grade 1B). For patients with AF and mitral stenosis, we recommend anticoagulation with an oral VKA (Grade 1C+). For patients with AF and prosthetic heart valves, we recommend anticoagulation with an oral VKA (Grade 1C+); the target INR may be increased and aspirin added depending on valve type and position, and on patient factors. For patients with AF of > or = 48 h or of unknown duration for whom pharmacologic or electrical cardioversion is planned, we recommend anticoagulation with an oral VKA for 3 weeks before and for at least 4 weeks after successful cardioversion (Grade 1C+). For patients with AF of > or = 48 h or of unknown duration undergoing pharmacologic or electrical cardioversion, an alternative strategy is anticoagulation and screening multiplane transesophageal echocardiography (Grade 1B). If no thrombus is seen and cardioversion is successful, we recommend anticoagulation for at least 4 weeks (Grade 1B). For patients with AF of known duration < 48 h, we suggest cardioversion without anticoagulation (Grade 2C). However, in patients without contraindications to anticoagulation, we suggest beginning IV heparin or low molecular weight heparin at presentation (Grade 2C).

Prognostic differences between atrial fibrillation and atrial flutter

This report presents the outcome of a cohort of 94 patients with atrial fibrillation from the Canadian Registry of Atrial Fibrillation, in which we paid particular attention to the probability of stroke and death. We also evaluated warfarin use over time and compared left atrial dimensions in patients with atrial flutter with those with atrial fibrillation.

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

STUDY OBJECTIVES

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).

DESIGN AND SETTINGS

Cross-sectional study at a university hospital.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

[Systemic embolism after reversion to sinusal rhythm of persistent atrial flutter]

BACKGROUND

The incidence of embolism in atrial flutter has been underestimated in the routine clinical practice.

PATIENTS AND METHODS

In this study the incidence of thromboembolic events after restoration of sinus rhythm (by catheter ablation or cardioversion) was compared in two groups of consecutive patients, with a different anticoagulation protocol. A total of 169 patients were evaluated. A first retrospective analysis of 79 non anticoagulated patients (group I). A second prospective group of 90 patients who were treated with an anticoagulation protocol (group II) similar to that for patients with atrial fibrillation. All had typical atrial flutter of at least one month's duration before the procedure.

RESULTS

The mean age of patients in group I was 61 12 years and the mean left ventricular ejection fraction was 57 6%. Patients in group II had a mean age of 61 10 years and the mean left ventricular ejection fraction was 56 9%. No differences were observed regarding prevalence of structural cardiopathy, arterial hypertension, diabetes mellitus, left ventricular dysfunction, atrial size or atrial fibrillation between the two groups of patients. Four patients in the retrospective analysis (5%) had an embolic event associated with the procedure, compared with 0 (0%) in the group of patients treated with the anticoagulation protocol. The efficient anticoagulation was associated with a lower risk of thromboembolic events (p < 0.05).

CONCLUSIONS

The incidence of embolic events after reversion to sinusal rhythm of persistent atrial flutter can be decreased. These patients should follow the same recommendations of anticoagulation that apply for patients with persistent atrial fibrillation that are going to be reverted to sinus rhythm.

Thromboembolic risk of patients referred for radiofrequency catheter ablation of typical atrial flutter without prior appropriate anticoagulation therapy

BACKGROUND

Radiofrequency catheter ablation of isthmus dependent atrial flutter is considered the therapy of choice. There is, however, controversy with regard to the thrombogenicity of atrial flutter in comparison with atrial fibrillation.

METHODS

Consecutive patients scheduled for catheter ablation of documented typical atrial flutter receiving insufficient (INR < 2.0) or no anticoagulation during the three weeks preceding the procedure underwent multiplane transesophageal echocardiography (TEE). Patients with exclusive documentation of atrial flutter were classified as group I, whereas patients with additional documentation of atrial fibrillation were classified as group II.

RESULTS

The study included 201 patients, 62 of whom were not on therapeutic anticoagulation (mean age 64 +/- 9 years, 87% men). In 10 of these 62 patients (16%), TEE detected a left atrial (LA) appendage thrombus in 4, or dense spontaneous echo contrast (SEC) in 6 patients. Comparison of patients with versus without SEC or thrombus, revealed a higher incidence of valvular heart disease (60% vs 26%, P = 0.05), but no differences with respect to age, gender, LA diameter, left ventricular end-diastolic diameter, or left ventricular ejection fraction. The incidence of positive TEE findings in group I was 1 in of 36 versus 9 of 26 in group II (3% vs 35%, P < 0.001), and the relative risk for thromboembolism in group II versus group I was 12.5 (95% CI: 3-55, P < 0.001).

CONCLUSION

There is a significant risk for thromboembolism in patients referred for ablation of typical atrial flutter who have not been appropriately anticoagulated.

Variable electrocardiographic characteristics of isthmus-dependent atrial flutter

OBJECTIVES

The purpose of this study was to characterize variations in flutter-wave (F-wave) morphology among patients with clockwise isthmus-dependent (CWID) and counterclockwise isthmus-dependent (CCWID) right atrial flutter (AFL) and to attempt to correlate F-wave morphology with echocardiographic data and clinical patient characteristics.

BACKGROUND

Variations in F-wave morphology on surface electrocardiogram (ECG) during CCWID and CWID flutter have been reported but never systematically characterized.

METHODS

Over a four-year period, 139 patients with AFL on ECG underwent electrophysiologic study and echocardiography at our institution. Electrocardiographic data, intracardiac recordings, echocardiographic data, and patient characteristics were reviewed retrospectively.

RESULTS

Of 156 AFLs evaluated, 130 were CCWID, 26 were CWID. Three types of CCWID flutter were observed: type 1 had purely negative F-waves inferiorly, types 2 and 3 had F-waves inferiorly with small (type 2) or broad (type 3) positive terminal deflections; CCWID flutter types 2 and 3 were associated with higher incidence of left atrial (LA) enlargement, heart disease, and atrial fibrillation (Afib) than type 1. Two types of CWID flutter were observed: type 1 had notched positive F-waves with a distinct isoelectric segment inferiorly. Type 2 had broader F-waves inferiorly with positive and negative components and a short isoelectric segment.

CONCLUSIONS

Variable ECG patterns for CCWID and CWID AFL exist. A positive component of the F-wave in the inferior leads during CCWID flutter is associated with an increased likelihood of heart disease, Afib, and LA enlargement.

Embolic complications of direct current cardioversion of atrial arrhythmias: association with low intensity of anticoagulation at the time of cardioversion

OBJECTIVES

The goal of this study was to identify the factors responsible for embolic complications of direct current (DC) cardioversion of atrial arrhythmias.

BACKGROUND

Direct current cardioversion of atrial fibrillation (AF) carries a risk of thromboembolism, which is reduced, but not eliminated, by anticoagulation. The risk of embolism after conversion of atrial flutter is believed to be lower. No series to date has included enough patients receiving anticoagulants or enough patients with atrial flutter to estimate the risk in these groups.

METHODS

We reviewed the case records of 1,950 patients who underwent 2,639 attempts at DC cardioversion.

RESULTS

Cardioversion was performed within two days of the apparent onset of the arrhythmia in 443 episodes, 352 without subsequent prolonged anticoagulation with one embolic complication. Cardioversion was preceded by warfarin therapy for > or = 3 weeks in 1,932 instances. No embolic complication occurred in 779 attempts performed with an international normalized ratio (INR) of > or = 2.5 (95% confidence limits 0% to 0.48%). Of 756 cases in which the INR was <2.5 or was not measured before conversion, nine were complicated by thromboembolism. Embolism was significantly more common at an INR of 1.5 to 2.4 than at an INR > or = 2.5 (0.93% vs. 0%, p = 0.012). The incidence of embolism after conversion of atrial flutter or tachycardia was similar to that after cardioversion of AF (0.72% vs. 0.46%, p = NS).

CONCLUSIONS

The INR should be > or = 2.5 at the time of cardioversion if the duration of AF is uncertain or >2 days. Cardioversion of atrial flutter presents similar risks and requires similar anticoagulation.

Catheter ablation of atrial flutter and macroreentrant atrial tachycardia

Catheter ablation has evolved from an experimental technique to first-line therapy for the treatment of atrial flutter. Atrial flutter is characterized by a macroreentrant atrial tachycardia circuit. Successful ablation of atrial flutter involves (1) mapping the atrial flutter to define the conduction zones within the re-entrant circuit to determine whether the atrial flutter is isthmus-dependent, non-isthmus-dependent, or atypical; (2) interrupting the atrial flutter macroreentrant circuit with an ablation catheter by creating either focal or linear lesions within a critical zone of slow conduction that extends to anatomical borders; and (3) terminating the tachycardia and demonstrating conduction block within the atrial flutter circuit after ablation. This update discusses the classification schemes of atrial flutter and macroreentrant atrial tachycardias, reviews the technique of radiofrequency catheter ablation, and highlights recent ablation approaches for atrial flutters and macroreentrant atrial tachycardias.

Thromboembolic complications after electrical cardioversion in patients with atrial flutter

PURPOSE

To determine the incidence of thromboembolic complications after cardioversion in patients with atrial flutter.

SUBJECTS AND METHODS

We reviewed 615 electrical cardioversions performed electively in 493 patients with atrial flutter. Embolic complications were evaluated during the 30 days after cardioversion. Follow-up data were obtained by follow-up visits and by contacting the treating physician.

RESULTS

Anticoagulants had been administered in 415 cardioversions (67%). Cardioversion was successful in 570 procedures (93%). Three embolic events (in 3 patients) occurred in the 30 days after 550 successful cardioversions with completed follow-up (0.6% of successful procedures; 95% confidence interval, 0.1% to 1.6%). Two of the 3 patients had not been anticoagulated, whereas the third patient had subtherapeutic oral anticoagulation. No embolic event occurred in procedures performed with adequate anticoagulation. The incidence of embolism in patients regardless of subtherapeutic anticoagulation was 1% (3 of 303 successful cardioversions).

CONCLUSIONS

We observed a low (0.6%) incidence of postcardioversion thromboembolic complications in patients with atrial flutter. Embolic events did not occur in patients with adequate anticoagulation.

Different patterns of interatrial conduction in clockwise and counterclockwise atrial flutter

BACKGROUND

The terms counterclockwise (CC) and clockwise (C) atrial flutter (Afl) are used to describe right atrial activation around the tricuspid valve in the left anterior oblique view. The manner in which the left atrium is activated, as reflected by coronary sinus (CS) recordings, has not been systematically evaluated.

METHODS AND RESULTS

Nine patients with both CC and C Afl underwent electrophysiological study with CS recordings during both rhythms with the use of a decapolar catheter with the tip placed in the distal CS. Patterns of CS activation during each type of Afl as well as during during sinus rhythm were categorized into 1 of 3 patterns: sequential proximal-to-distal, sequential distal-to-proximal, and fused, indicating activation from different directions. In 7 of 9 patients, the pattern of CS activation in CC Afl and C Afl differed, with a proximal-to-distal pattern in CC Afl and a fused pattern in C Afl. In 2 patients, pacing the high right atrial septum near the presumed site of Bachmann's bundle in sinus rhythm showed a similar fused pattern of CS activation.

CONCLUSIONS

These results demonstrate different patterns of CS activation in CC Afl and C Afl in the majority of patients and are consistent with a model in which the left atrium is activated predominantly over Bachmann's bundle during C Afl and over the CS os in CC Afl. These findings may have implications for maintenance of Afl, interpretation of flutter wave morphology on surface ECG, and left atrial mechanical function in Afl.

Restoration of atrial mechanical function after successful radio-frequency catheter ablation of atrial flutter

BACKGROUND

Atrial mechanical dysfunction and its recovery time course after successful radiofrequency ablation of chronic atrial flutter (AFL) has been largely unknown. We serially evaluated left atrial function by echocardiography after successful ablation of chronic atrial flutter.

METHODS

In 13 patients with chronic AFL, mitral E wave A wave, and the ratio of A/E velocity were measured at 1 day, 1 month, 3 months and 6-12 months after successful radiofrequency (RF) ablation. Doppler tissue imaging (DTI) technique was also used to avoid load-dependent variation in the flow velocity pattern.

RESULTS

Left atrial mechanical function, assessed by A wave velocity and the annular motion, was depressed at 1 day, but improved significantly at 1 month and maintained through 6-12 months after the ablation. Left atrial size did not change significantly.

CONCLUSION

Left atrial mechanical function was depressed immediately after successful RF ablation of chronic AFL, but it improved significantly after 1 month and was maintained over one year.

Safety of electrical cardioversion in patients with previous embolic events

OBJECTIVE

To assess thromboembolic complications in cardioversions in patients with atrial fibrillation or flutter and a previous embolic event.

PATIENTS AND METHODS

The study population consisted of 104 patients with previous embolic events who underwent 128 electrical cardioversions for termination of atrial fibrillation or flutter. The primary outcome measure was successful cardioversion.

RESULTS

Anticoagulants were administered in 118 procedures (92%). Cardioversion was successful in 108 (84%) of the 128 procedures. Only 1 embolic event occurred within 30 days after cardioversion (incidence, 0.9% of successful procedures; 95 % confidence interval, 0.02%-5.3%). The single embolic event was a transient neurologic deficit occurring 22 days after cardioversion in a patient with previous atrial fibrillation. This patient had a sub-therapeutic level of anticoagulation. Transesophageal echocardiography revealed no spontaneous echo contrast or thrombi before the procedure. No thromboembolism was noted in patients who had therapeutic anticoagulation or in those with failed cardioversion.

CONCLUSION

Patients with previous embolism are not at additional risk of thromboembolic complications after cardioversion if anticoagulation is adequate.

Risk of stroke in patients with atrial flutter

Using a Medicare-based retrospective cohort study, the stroke risk in patients with atrial flutter (RR = 1.41) was determined to be greater than that in a control group (RR = 1.00) but less than that in an atrial fibrillation group (RR = 1.64). Furthermore, patients with atrial flutter who subsequently had an episode of atrial fibrillation had a higher risk of stroke (RR = 1.56) than patients with atrial flutter who never had a subsequent episode of atrial fibrillation (RR = 1.11).

Clinical dysrhythmias after surgical repair of congenital heart disease

Innovations in surgical and medical treatment continue to improve the outlook for children with complex congenital heart disease. Although mortality continues to decrease, disease-related morbidity is increasing as a large cohort of these patients is reaching young adulthood, pursuing careers, marrying, and in many cases having children of their own. Chronic recurrent dysrhythmias are a frequent cause of long-term morbidity in this population and result in frequent, unanticipated emergency room visits and hospitalizations. Although not usually life threatening, they can pose considerable challenges to the patients and the providers who care for them. This article provides an overview of the most common dysrhythmias encountered in this population, dysrhythmia substrates, and therapeutic options.

Atrial arrhythmias

Atrial arrhythmias are commonly encountered by the primary care clinician. They are usually asymptomatic or have only minor symptoms, unless the ventricular rate becomes very rapid. The challenges for the clinician are to recognize the benign from the more severe arrhythmias, to identify and treat the precipitating cause, to control the symptoms that concern the patient, and to prevent any complications. There are new medicinal and nonmedicinal treatments available that offer greater likelihood of acute and long-term success in the treatment, and sometimes cure, of the original arrhythmias.

Spontaneous echo contrast: where there's smoke there's fire

Left atrial (LA) spontaneous echo contrast (SEC), or "smoke," is a frequent finding on transesophageal echocardiography (TEE), but it is rarely detected with transthoracic echocardiography. LA SEC is characterized by dynamic smoke-like echoes within the LA cavity or appendage. Most patients with LA SEC have atrial arrhythmias, mitral stenosis, or a mitral valve prosthesis, and they have an enlarged LA, conditions that are associated with LA stasis. Conversely, mitral regurgitation is protective against LA SEC. LA SEC is present in almost all patients with LA thrombus and is associated with previous embolic events in many patient populations. In patients with nonvalvular atrial fibrillation, LA SEC predicts future embolism and death. LA SEC may therefore assist in selecting patients with atrial fibrillation or with mitral stenosis and sinus rhythm who benefit the most from anticoagulation. Hematological studies have shown that LA SEC is a marker of an hypercoagulable state. LA SEC is a manifestation of red cell aggregation, arising from an interaction between red cells and plasma proteins such as fibrinogen, at low shear rates. LA SEC does not require platelets. The detection of LA SEC on ultrasound arises from the increased amplitude of backscatter from red cell aggregates rather than single cells. Patients with LA SEC should be considered for anticoagulant therapy and may require correction of underlying cardiovascular abnormalities. Future directions in LA SEC include further assessment of integrated backscatter for quantification, assessment of its prognostic role in clinically low-risk patients with nonvalvular AF, and novel pharmacological treatment.