Thromboembolism in chronic atrial flutter: is the risk underestimated?

Right Heart and Wrong Rhythm: Atrial Flutter in Dextrocardia

Atrial flutter is characterized by rapid atrial activity, causing an abnormal heart rhythm. Recognition and prompt management are of utmost importance since this cardiac arrhythmia could increase the risk of thromboembolic stroke and atrial fibrillation, which may lead to disability and death. Risk factors include myocardial infarction, surgery, medication, and structural heart abnormalities. One distinctive structural abnormality is dextrocardia. Herein, we present a case of a 47-year-old male who initially complains of difficulty in ambulation. Further workup showed atrial flutter with rapid ventricular response on electrocardiogram (ECG) and dextrocardia on imaging. This case tackles the possible association between dextrocardia and arrhythmias, which was an atrial flutter, its management, and treatment outcomes.

Atrial Appendage Thrombosis Risk Is Lower for Atrial Flutter Compared with Atrial Fibrillation

BACKGROUND

The risk of stroke and thromboembolism in atrial fibrillation is established. However, the evidence surrounding the risk of thromboembolism in patients with atrial flutter is not as clear. We hypothesized that atrial flutter would have indicators of less risk for thromboembolism compared with atrial fibrillation on transesophageal echocardiography, thereby possibly leading to a lower stroke risk.

METHODS

A retrospective review of 2225 patients undergoing transesophageal echocardiography was performed. Those with atrial fibrillation or atrial flutter were screened. Exclusion criteria were patients being treated with chronic anticoagulation, the presence of a prosthetic valve, moderate to severe mitral regurgitation or stenosis, congenital heart disease, or a history of heart transplantation. A total of 114 patients with atrial fibrillation and 55 patients with atrial flutter met the criteria and were included in the analysis.

RESULTS

Twelve patients (11%) in the atrial fibrillation group had left atrial appendage thrombus versus zero patients in the atrial flutter group (P < .05). The prevalence of spontaneous echocardiography contrast was significantly higher and left atrial appendage emptying velocity was significantly lower in the atrial fibrillation group compared with the atrial flutter group (P < .001). No spontaneous contrast was seen when the left atrial appendage emptying velocity was >60 cm/sec.

CONCLUSIONS

Patients with atrial flutter have a lower incidence of left atrial appendage thrombi, higher left atrial appendage emptying velocity, and less left atrial spontaneous contrast compared with patients with atrial fibrillation, suggesting a lower risk for potential arterial thromboembolism.

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.

New oral anticoagulants in patients undergoing atrial flutter radiofrequency catheter ablation: an observational study

AIM

Atrial flutter (AFL) ablation requires optimal periprocedural anticoagulation in order to minimize thromboembolic events/bleeding risk. This study describes the characteristics of patients receiving new oral anticoagulants before AFL ablation and assesses complications.

METHODS

This multicenter, retrospective study reports ischemic and hemorrhagic predischarge, postprocedural complications.

RESULTS

We evaluated 60 patients (62.3% male; mean age: 69.2 ± 9.7 years; CHA2DS2-VASc score: 2.44 ± 1.46, HAS-BLED score: 1.14 ± 0.7). Twenty-one (35.0%) and 23 patients (38.3%) received twice-daily dabigatran 110 or 150 mg; 16 patients (26.6%) received once-daily rivaroxaban (15 mg [n = 5] or 20 mg [n = 11]). Four cases of postprocedural minor bleeding were reported.

CONCLUSION

This is the first study assessing new oral anticoagulants for periprocedural anticoagulation, specifically in patients undergoing AFL ablation. No major bleeding was reported. Further prospective investigation is warranted.

Atrial fibrillation in the elderly

This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted.

Non-surgical left atrial appendage closure for stroke prevention in atrial fibrillation

Non-Surgical Left Atrial Appendage Closure for Stroke Prevention in Atrial Fibrillation. The most feared complication associated with atrial fibrillation (AF) is stroke, the risk of which increases with advanced age. Because of its complex anatomy and diminished blood flow during AF, the left atrial appendage (LAA) has been a common site of left atrial thrombi and presumed source of thromboembolism. Systemic anticoagulation to treat what may be largely a localized phenomenon is associated with significant complications. Newer anticoagulation agents hold great promise in facilitating dosing and eliminating drug and food interactions, but do not eliminate bleeding risk. These challenges have led to interest in mechanical exclusion of the LAA as a means of preventing thromboembolism in AF. Although surgery permits greater visualization and management of complications, the potential morbidity has limited adoption in often-frail elderly patients. In this paper, we review the current state of percutaneous left atrial exclusion for stroke prevention in AF, and the strengths and limitations of each of these strategies. The nonsurgical approaches to excluding the LAA from the central circulation can be divided into 3 broad categories: transseptally placed devices, percutaneous epicardial approach, and hybrid approaches. The availability of several approaches will allow physician selection of the optimal approach for a given patient based on clinical, physiological, and anatomical considerations. LAA exclusion stands to become an increasingly attractive option for patients with nonvalvular AF because it can be offered to elderly AF patients, and eliminates the long-term cumulative bleeding risks and adherence challenge of anticoagulants.

Prevalence of use of anticoagulants in 502 elderly hospitalized patients at increased risk for systemic embolism or venous thromboembolism without contraindications to anticoagulants in a university hospital

We investigated, in a university hospital, the prevalence of use of anticoagulants in 502 elderly hospitalized patients at increased risk for systemic embolism or venous thromboembolism without contraindications to anticoagulants. The 502 patients included 291 men and 211 women with a mean age of 77 +/- 7 years (range, 65-98 years). Anticoagulants were used to treat 479 of 502 hospitalized patients (95%) at increased risk for systemic embolism or venous thromboembolism. Of the 479 patients treated with anticoagulants, 317 (66%) were treated with unfractionated heparin, 203 (42%) with warfarin, 81 (17%) with low-molecular-weight heparin, two (<1%) with fondaparinux, and two (<1%) with argatroban.

TEE screening in Atrial flutter: A single-centre experience with retrospective validation of a new risk score for the presence of atrial thrombi

Transesophageal echocardiography (TEE) has been proposed as a screening tool to exclude the presence of atrial thrombi and left atrial spontaneous echocontrast before cardioverting persistent atrial flutter (AFl) and atrial fibrillation (AF). However in pure AFl a very low prevalence of atrial thrombi has been observed by many investigators: a confirmation of this finding would make TEE screening redundant. We review our database of patients with AFl who underwent TEE screening before cardioversion in the last 5 years. A new risk score for the presence of left atrial thrombus (AFLAT score) is here proposed, as a potential tool to avoid unnecessary TEE exams. Out of the 106 patients examined, in fourteen left atrial thrombi were diagnosed (13%). Only two cases belonged to the pure AFl subgroup (prevalence=3%), while twelve cases were detected in the subgroup of AFl patients with previous AF episodes (prevalence=32%, p<0.001). All of the fourteen patients with a positive TEE for thrombus were identified by a AFLAT score >2. The validation of this index in a larger and prospective setting would lead to a 85% reduction in unnecessary TEE exams in patients with pure AFl undergoing cardioversion.

Acute anticoagulation adjustment in patients with atrial fibrillation at risk for stroke: approaches, strategies, risks and benefits

The acute management of anticoagulation in patients with atrial fibrillation to prevent stroke and other thromboembolic complications includes the use of individualized strategies tailored to the patient and based on the situation (cardioversion, surgeries, dental procedures, cardiac interventions, other invasive procedures and initiation of, or adjustment to, warfarin dosing). The vast range of choices can cause confusion and few randomized controlled clinical trials in this area provide adequate guidance. Chronic anticoagulation management is more straightforward since clinical evidence is ample, randomized clinical trial data provides cogent informaiton and guidelines have been established. Acute management of anticoagulation in patients with atrial fibrillation to prevent thromboembolic complications is often unrecognized but is emerging as a crucial, but challenging, and increasingly complex aspect of the care of patients with atrial fibrillation. This review addresses issues regarding such patients who may be at risk for stroke and require acute adjustments of anticoagulation (in light of, or in lieu of, chronic anticoagulation). Several promising new strategies are considered in light of established medical care. This analysis provides practical recommendations based on available data and presents results from recent investigations that may provide insight into future strategies.

Echocardiography in atrial fibrillation

Atrial fibrillation is the most commonly encountered sustained arrhythmia. Echocardiography has augmented the knowledge about etiology and complications of atrial fibrillation. Transthoracic echocardiography allows rapid, safe and comprehensive assessment of cardiac structure and function, and is recommended for all subjects with atrial fibrillation. The use of transesophageal echocardiography has contributed to a better understanding of the thromboembolic risk in patients with atrial fibrillation, especially in the setting of electrical cardioversion. Several investigators have demonstrated the feasibility and safety profile of early cardioversion with short-term anticoagulation in patients with atrial fibrillation and a transesophageal echocardiography negative for atrial thrombi. More recently, transesophageal and intracardiac echocardiography have been employed in patients with atrial fibrillation to monitor percutaneous procedures such as pulmonary veins radiofrequency ablation or left atrial appendage obliteration. In this review the available echocardiographic imaging modalities and their specific role in the evaluation and management in atrial fibrillation are described.

Prevalence of inducible paroxysmal supraventricular tachycardia during esophageal electrophysiologic study in patients with unexplained stroke

BACKGROUND

The relationships between stroke and atrial tachycardia or atrial fibrillation were previously reported. Electrophysiological study is one of the means, used to detect and evaluate these atrial tachyarrhythmias. But, some other arrhythmias as paroxysmal supraventricular tachycardia, can be induced during electrophysiologic study and their significance in stroke is unknown. The aim of the study was to assess the significance of inducible paroxysmal supraventricular tachycardia (PSVT) in stroke.

METHODS

One hundred thirty seven patients, aged 61+/-12 years had unexplained stroke (group I) and were compared to 60 subjects aged 45+/-18.5 years without stroke and history of tachycardia (group II); Holter monitoring (HM), echocardiogram and esophageal electrophysiologic study (EPS) in basal state and after isoproterenol were performed.

RESULTS

Heart disease was noted in 19 group I patients (14%) and 10 group II patients (17%). In group I, atrial fibrillation or tachycardia (AF-AT) was induced in 20 patients (15%) and PSVT was induced in 19 patients (14%) aged 66+/-12 years. In group II, AF/AT was induced in 3 patients (5%); no group II patient had induced PSVT. After 3+/-1 years, in group I, one of 98 patients without induced arrhythmias had new strokes and 2 had AF; 5 patients with induced AT/AF developed AF; 5 patients with induced PSVT had PSVT's, requiring ablation in 4 of them; 1 died from a new stroke; one had a second non-fatal stroke and 3 patients developed AF (16%). In group II, there were no events.

CONCLUSION

In 14% of patients with unexplained stroke, PSVT was inducible during esophageal electrophysiologic study. Further studies are warranted to assess the significance of this finding in patients with unexplained stroke.

Atrial flutter and the risk of thromboembolism: a systematic review and meta-analysis

PURPOSE

We conducted a systematic review and meta-analysis of observational studies to assess the risk of thromboembolism associated with atrial flutter.

METHODS

MEDLINE, EMBASE, bibliographies, and consultation with clinical experts were used to identify studies that report the risk of thromboembolism associated with attempted cardioversion and longer-term risk in chronic atrial flutter. The review process and data extraction were performed by two reviewers. Study event rates were assessed graphically, and a chi-squared test was used to assess heterogeneity across studies. Meta-regression with weighted logistic regression was used to assess the association between study-level clinical factors and reported thromboembolic event rates.

RESULTS

We found 13 studies that reported the risk of thromboembolism associated with cardioversion of atrial flutter. Short-term event rates ranged from 0% to 7.3%. A chi-squared test for heterogeneity was significant (P < 0.001), so results were not pooled. Instead, a meta-regression analysis was performed, which partly explained the heterogeneity across studies. Studies were more likely to report high event rates when they included patients with a prior history of thromboembolism, and to report lower event rates when at least some patients were anticoagulated or if patients underwent echocardiography before cardioversion. Four studies reported the longer-term risk of thromboembolism, and these suggest a yearly event rate of approximately 3% with sustained atrial flutter.

CONCLUSION

These findings suggest that atrial flutter is indeed associated with an increased risk of thromboembolism, and that clinical factors account for the low event rates reported in some studies.

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.

Electrical cardioversion of atrial fibrillation

External direct current cardioversion remains the most common and effective method for restoration of normal sinus rhythm in patients with persistent AF. The development of biphasic defibrillators allows for higher success rates of conversion using standard energy levels. For persistent AF, an initial energy of 200 J is recommended for biphasic defibrillators, and 300 to 360 J are recommended for monophasic defibrillators, with the electrodes placed in the anterior posterior position. For refractory cases, alternatives are available such as dual defibrillators or internal cardioversion. Antiarrhythmic drugs may enhance the results of cardioversion by helping overcome shock failure or by preventing immediate recurrence of AF. Thromboembolism is the most important complication associated with cardioversion, but it can be prevented by providing 3 weeks of anticoagulation before the procedure or by excluding the presence of thrombi by transesophageal echocardiography, followed by an additional 4 weeks of anticoagulation.

Anticoagulation for atrial fibrillation

For over two decades, valuable insights have been accumulated from epidemiologic studies and randomized trials about the risks for and prevention of AF-related stroke. AF substantially raises the risk of stroke, most likely through an atrio-embolic mechanism. Warfarin and other members of its class of oral anticoagulants targeted at an INR of 2.5 can abrogate the risk of stroke attributable to AF effectively and fairly safely. High-quality management of anticoagulation can be achieved in usual clinical care. These insights have important implications for the care of individual patients and more generally for public health. Future research is needed to specify the risk of stroke and hemorrhage among patients with AF better, particularly among older individuals, to optimize use of antithrombotic agents, and to define the role of recently developed antithrombotic drugs and invasive nondrug approaches.

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.

Recurrence rate of atrial flutter after initial presentation in patients on drug treatment

Atrial flutter (AFl) recurrence after initial in-patient presentation, cardioversion, and drug treatment is almost universal, often leading to rehospitalization and risk of serious clinical consequences. Radiofrequency ablation of AFl, which has an excellent safety record, should be evaluated as a first-line approach for most patients with AFl.

[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.

Outpatient cardioversion of atrial arrhythmias: efficacy, safety, and costs

BACKGROUND

Outpatient direct current (DC) cardioversion is performed routinely, yet scant data support this approach. We studied the efficacy, safety, and costs of outpatient cardioversion.

METHODS

A retrospective analysis of outpatient cardioversions was performed in a 5-year period at an academic medical center in 532 consecutive outpatients with an atrial tachyarrhythmia. The protocol included anticoagulation (international normalized ratio >or=2.0) for >or=4 consecutive weekly draws and then DC cardioversion with the patient under intravenous anesthesia. Arrhythmia symptoms, antiarrhythmic therapy use, and costs were evaluated.

RESULTS

Ninety percent of patients were discharged in sinus rhythm after cardioversion with a median number of shocks of 1 (range, 1-6) for atrial flutter (n = 113), atrial tachycardia (n = 13), and atrial fibrillation (n = 406). Sixty-seven percent of patients were treated with an antiarrhythmic drug. The complication rate was 2.6%, with 11 unplanned admissions. Thromboemboli occurred only in patients whose anticoagulation deviated from protocol and included chronic hemianopsia starting 4 days after cardioversion, transient right-sided weakness, and cerebral vascular accident 3 days after cardioversion, despite negative results on a transesophageal echocardiogram. Two patients had postcardioversion pulmonary edema. Bradycardia developed in 4 patients; transient pacemaker noncapture after the shock occurred in 4 patients. Transient postshock rhythms also included AV nodal Wenckebach and junctional rhythm. One patient had aspiration pneumonia. The mean cost of cardioversion was 464 dollars. Fees for anesthesia ranged from 525 dollars to 650 dollars. The anesthetic costs ranged from 2.84 dollars to 21.47 dollars. The cardiology fee averaged 501 dollars.

CONCLUSION

Outpatient cardioversion is a low risk, effective, and economical procedure.

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.

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.

Prevalence of left atrial chamber and appendage thrombi in patients with atrial flutter and its clinical significance

OBJECTIVES

The study was done to assess the prevalence of left atrial (LA) chamber and appendage thrombi in patients with atrial flutter (AFl) scheduled for electrophysiologic study (EPS), to evaluate the prevalence of thromboembolic complications after transesophageal echocardiographic (TEE)-guided restoration of sinus rhythm and to evaluate clinical risk factors for a thrombogenic milieu.

BACKGROUND

Recent studies showed controversial results on the prevalence of atrial thrombi and the risk of thromboembolism after restoring sinus rhythm in patients with AFl.

METHODS

Between 1995 and 1999, patients with AFl who were scheduled for EPS were included in the study. After transesophageal assessment of the left atrial appendage and exclusion of thrombi, an effective anticoagulation was initiated and patients underwent EPS within 24 h.

RESULTS

We performed 202 EPSs (radiofrequency catheter ablation, n = 122; overdrive stimulation, n = 64; electrical cardioversion, n = 16) in 139 consecutive patients with AFl. Fifteen patients with a thrombogenic milieu were identified. All of them had paroxysmal atrial fibrillation (AF). Transesophageal echocardiography revealed LA thrombi in two cases (1%). After EPS no thromboembolic complications were observed. Diabetes mellitus, arterial hypertension and a decreased left ventricular ejection fraction were found to be independent risk factors associated with a thrombogenic milieu.

CONCLUSIONS

The findings of a low prevalence of LA appendage thrombi (1%) in patients with AFl and a close correlation between a history of previous embolism and paroxysmal AF support the current guidelines that patients with pure AFl do not require anticoagulation therapy, whereas patients with AFl and paroxysmal AF should receive anticoagulation therapy. In addition, the presence of clinical risk factors should alert the physician to an increased likelihood for a thrombogenic milieu.

Atrial Flutter

Atrial flutter (AFl) is an arrhythmia resulting from reentry in a macroreentrant circuit, most commonly in the right atrium. Typical AFl uses the narrow isthmus of right atrial tissue between the tricuspid valve annulus and the inferior vena cava orifice as part of the macroreentrant circuit. The treatment of AFl is directed toward achieving the following four goals. 1) In the presence of AFl, adequate rate control is required, which can be achieved in most but not all patients by oral or intravenous digoxin, calcium channel blockers, or beta-blockers, alone or in combination. 2) Anticoagulation with warfarin should be considered in patients with recurrent AFl, especially those over 70 years of age, and those with a history of atrial fibrillation, stroke, or structural heart disease. 3) Conversion to sinus rhythm can be achieved in up to 70% of patients with intravenous ibutilide, but this should be reserved for patients with either normal hearts or only mild left ventricular dysfunction. Direct-current cardioversion is nearly 100% effective and is ideal for patients with left ventricular dysfunction. 4) Long-term maintenance of sinus rhythm may be achieved in up to 50% to 60% of patients by using antiarrhythmic drugs, including sotalol, amiodarone, dofetilide, propafenone, and flecainide, but with the potential for causing significant proarrhythmia and side effects. Radiofrequency catheter ablation may cure over 90% of patients with type 1 AFl (using the tricuspid valve to inferior vena cava isthmus), and from 70% to 90% of patients with atypical AFl. Newer mapping techniques, such as electroanatomic mapping, are likely to further reduce procedure time and improve success rates.

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.

Adequacy of anticoagulation in patients with atrial fibrillation: effect of various parameters

BACKGROUND

Despite reported evidence of the vital importance of appropriate anticoagulation in patients with chronic atrial fibrillation for stroke prevention, this treatment modality still lags behind optimal requirements.

HYPOTHESIS

Our objectives were to evaluate various doctor or patient-related factors that influence quality of control and to assess the adequacy of anticoagulation provided by physicians in the community.

METHODS

In a retrospective study, International Normalized Ratio (INR) values obtained immediately on admission to hospital were considered representative of previous long-term control.

RESULTS

Only 42% of the relevant 385 patient population fell within the protective anticoagulation range of INR 1.91-4.1. The respective figures for patients with poor (INR < 1.5) or suboptimal (INR 1.51-1.9) control, as well as those whose INR values risked bleeding (INR > 4.1), were 28.3, 14.1, and 15.6%. Patient involvement in treatment positively influenced quality of control. By contrast, age 70-80 years or absence of congestive heart failure negatively affected quality of anticoagulation [p = 0.07, odds ratio (OR), 1.7 (95% confidence interval. 0.94-3.08), p = 0.014, OR, 2.06 (95% confidence interval, 1.15-3.7) respectively]. The percentage of patients admitted with stroke who had been adequately anticoagulated was significantly lower than that of patients who had no stroke (21 vs. 44.4%). Adequacy of anticoagulation in patients with cardiac prosthetic valves was superior compared with the rest of the patient population (56.7 vs. 42% with optimal, and only 14.5 vs. 28.3% with poor anticoagulation, respectively), indicating that under the same conditions a better quality of treatment could be achieved.

CONCLUSIONS

Adequacy of anticoagulation in patients with atrial fibrillation lags behind actual recommendations. Better control is required and achievable.

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.

Catheter ablation for cardiac arrhythmias

The safety and efficacy of catheter ablation for treatment of most types of cardiac arrhythmias are well established. These arrhythmias and arrhythmia substrates include AVNRT, accessory pathways, focal atrial tachycardia, atrial flutter, idiopathic ventricular tachycardia, and bundle-branch re-entry. Catheter ablation is considered as an alternative to pharmacologic therapy in the treatment of these cardiac arrhythmias.