Should all patients undergo transesophageal echocardiography before electrical cardioversion of atrial fibrillation?

Sonochemical-assisted synthesis of copper oxide nanoparticles with the plant-mediated approach and comparative evaluation of some biological activities

The present study reported a green approach for the sonochemical-assisted synthesis (SAS) of copper oxide nanoparticles (CuO NPs) by using the aqueous extract of the Ficus johannis plant. The aqueous extract was obtained using ultrasonic-assisted extraction (15 min, 45 °C) and microwave-assisted extraction (15 min, 450 w). Next, the as-prepared extracts were used in a plant-mediated approach for the green synthesis of CuO NPs. The synthesized CuO NPs have been characterized via different techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), ultraviolet-visible absorption, photoluminescence, and Fourier-transformed infrared (FT-IR) spectroscopic techniques. As observed, a broad absorption band around 375 nm clarified the successful synthesis of CuO NPs. From the SEM analysis, the average particle size of the prepared CuO NPs was estimated below 50 nm. In addition, the antimicrobial, antioxidant, and antifungal properties of the aqueous extracts as well as the as-prepared CuO NPs were evaluated by different assays. These included the release of protein, nucleic acids, disk diffusion method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and time-killing assays.

Effectiveness of Transesophageal Echocardiography in Preventing Thromboembolic Complications Before Cardioversion: A Narrative Review

Atrial fibrillation (AFib) is one of the most prevalent irregular heartbeats that doctors encounter. Clinicians typically pursue two main approaches for treatment, namely, controlling the heart rate and managing the heart rhythm. Under the rhythm control approach, AFib is addressed through cardioversion, which is achieved either with medications termed pharmacological cardioversion (PCV) or via an electrical shock termed electric cardioversion (ECV). While ECV proves instrumental in AFib management, it carries its own risk factors, potentially leading to blood clot-related complications such as embolic strokes. To counteract this potential downside, a well-established strategy involves the utilization of transesophageal echocardiography (TEE) to identify possible embolic sources before initiating cardioversion. The goal of this systematic review is to highlight the role of TEE in preempting embolic occurrences following ECV during the management of AFib. After conducting a thorough search of databases, namely, PubMed, PubMed Central, and Medline, a total of 36 studies were selected for this review article. Following a comprehensive evaluation of these studies, it was concluded that TEE plays a pivotal role in preventing thromboembolic complications during ECV for AFib. However, it is important to note that further research is needed to delve deeper into this matter. While existing evidence underscores its efficacy, additional investigation is needed to address this subject matter comprehensively.

Prevalence of left atrial thrombus by real time three-dimensional echocardiography in patients undergoing electrical cardioversion of atrial fibrillation: A contemporary cohort study

BACKGROUND

The prevalence of left atrial thrombi in patients scheduled for electrical cardioversion (ECV) of atrial fibrillation (AF) remains unknown in contemporary real-life practice.

METHODS AND RESULTS

Patients scheduled for ECV underwent transesophageal echocardiography (TEE) regardless of AF duration and type of anticoagulant. Of 277 consecutive patients (65% men, mean age 71 ± 10 years, CHA₂ DS₂ -VASc 3.1 ± 1.4), 92 were on direct oral anticoagulants (DOACs) and 99 on antivitamin K (AVK) oral agents for at least 3 weeks before and 4 after ECV. Eighty-five patients with paroxysmal AF on low-molecular-weight heparin were also considered. Real time three-dimensional TEE detected left atrial appendage (LAA) thrombus in 7% of patients, without significant difference among three groups (P = .334). Anticoagulation was ineffective in eight patients on AVK oral agents, two of them had thrombus. Eight patients assumed incorrectly DOACs, four of them had thrombus. Among the 175 patients on effective anticoagulation, five showed thrombus, three on AVK oral agents, and two on DOACs (P = .716). Effective anticoagulation was associated with reduced risk of thrombosis (OR: 0.16, 95%CI: 0.06-0.45, P = .001). In patients with correct anticoagulation, predictors of thrombus were CHA₂ DS₂ VASc (for each point of increment OR: 1.97, 95%CI: 1.08-3.61, P = .029), low left ventricular ejection fraction (OR: 0.92, 95%CI: 0.86-0.99, P = .026), and degree of spontaneous echo-contrast (for each point increase OR: 10, 95%CI: 2-39, P < .0001).

CONCLUSION

Patients with AF, on effective anticoagulation, had a prevalence of thrombus not negligible regardless of type of anticoagulant. TEE is prudent before ECV and mandatory if unsuccessful anticoagulation is proved or suspected.

Thromboembolic events around the time of cardioversion for atrial fibrillation in patients receiving antiplatelet treatment in the ACTIVE trials

Aims

It is unknown whether cardioversion of atrial fibrillation causes thromboembolic events or is a risk marker. To assess causality, we examined the temporal pattern of thromboembolism in patients having cardioversion.

Methods and results

We studied patients randomized to aspirin or aspirin plus clopidogrel in the ACTIVE trials, comparing the thromboembolic rate in the peri-cardioversion period (30 days before until 30 days after) to the rate during follow-up, remote from cardioversion. Among 962 patients, the 30-day thromboembolic rate remote from cardioversion was 0.16%; while it was 0.73% in the peri-cardioversion period [hazard ratio (HR) 4.1, 95% confidence interval (CI) 2.1–7.9]. The 30-day thromboembolic rates in the periods immediately before and after cardioversion were 0.47% and 0.96%, respectively (HR 2.2, 95% CI 0.7–7.1). Heart failure (HF) hospitalization increased in the peri-cardioversion period (HR 11.5, 95% CI 6.8–19.4). Compared to baseline, the thromboembolic rate in the 30 days following cardioversion was increased both in patients who received oral anticoagulation or a transoesophageal echocardiogram prior to cardioversion (HR 7.9, 95% CI 2.8–22.4) and in those who did not (HR 4.8, 95% CI 1.6–14.9) (interaction P = 0.2); the risk was also increased with successful (HR 4.5; 95% CI 2.0–10.5) and unsuccessful (HR 10.2; 95% CI 2.3–44.9) cardioversion.

Conclusions

Thromboembolic risk increased in the 30 days before cardioversion and persisted until 30 days post-cardioversion, in a pattern similar to HF hospitalization. These data suggest that the increased thromboembolic risk around the time of cardioversion may not be entirely causal, but confounded by the overall clinical deterioration of patients requiring cardioversion.

Clinical outcomes after AF cardioversion in patients presenting left atrial sludge in trans-esophageal echocardiography

BACKGROUND

Direct-current cardioversion (DCC) for atrial fibrillation carries a risk of stroke, probably associated with the temporary atrial stunning following cardioversion. The presence of a cardiac thrombus, usually localized in the left atrial appendage (LAA), is recognized as a clear contra-indication to the cardioversion. However, the presence of atrial sludge without LAA thrombus in trans-esophageal echocardiography (TEE) remains, for many cardiologists, a relative contra-indication to the cardioversion. The aim of this study was to evaluate the safety of DCC in patients presenting atrial sludge without LAA thrombus.

METHODS

We prospectively included all consecutive patients demonstrating atrial sludge without LAA thrombus in TEE and undergoing DCC for persistent atrial fibrillation (AF). Safety of DCC was evaluated by the occurrence of clinical events at 1 month following cardioversion, i.e., up to the end of the atrial stunning period, as assessed by clinical examination and the standardized and validated Questionnaire for Verifying Stroke-Free Status (QVSFS).

RESULTS

Over a period of 2 years, 21 patients presenting atrial sludge without LAA thrombus underwent DCC for AF. During the follow-up period of 1 month after DCC, no clinical embolic event, cardiac event, or unscheduled consultations/hospitalizations occurred. At 1 month, 67% of the patients remained in sinus rhythm.

CONCLUSION

No clinical event occurred in patients demonstrating atrial sludge without thrombus and undergoing DCC for AF. These findings support current guidelines that only keep atrial thrombus as a contraindication to cardioversion, but warrant further investigation in large studies.

Does Left Atrial Appendage Amputation During Routine Cardiac Surgery Reduce Future Atrial Fibrillation and Stroke?

Purpose of Review

Stroke is the most feared complication of atrial fibrillation. To prevent stroke, left atrial appendage exclusion has been targeted, as it is the prevalent site for formation of heart thrombi during atrial fibrillation.

We review the historic development of methods for exclusion of the left atrial appendage and the evidence to support its amputation during routine cardiac surgery.

Recent Findings

Evidence is not yet sufficient to routinely recommend left atrial exclusion during heart surgery, despite a high prevalence of postoperative atrial fibrillation. Observational studies indicate that electrical isolation of scarring from clip or suture techniques reduces the arrhythmogenic substrate.

Summary

Randomized studies comparing different methods of closure of the left atrial appendage before amputation do not exist. Such studies are therefore warranted, as well as studies that can elucidate whether amputation is superior to leaving the left atrial appendage stump. Potentially, thrombogenic remaining pouch after closure should be addressed.

Advances in anticoagulation management of patients undergoing cardioversion of nonvalvular atrial fibrillation

Atrial fibrillation (AF) is a major cause of stroke. The restoration of sinus rhythm through cardioversion, either chemical or electrical is a common practice. Interestingly, there is an incremental increase from the baseline risk for embolisation in the immediate post-cardioversion period, with most events occurring within 10 days from cardioversion. Especially patients with recent onset AF show the lowest rates of antithrombotic therapy, while having a high stroke risk. Despite the increased risk for embolisation, anticoagulation in patients undergoing cardioversion of atrial fibrillation is often inadequate. Moreover, since the implementation of non-vitamin K antagonists oral anticoagulants (DOACs) there are several therapeutic approaches for pericardioversion anticoagulant therapy and not all suits to all patients. In addition, the extensive use of transesophageal echocardiography provides an alternative strategy, especially useful for patients of high haemorrhagic risk. In this review article, we aim to provide an update on the anticoagulation strategies for patients undergoing cardioversion of non-valvular atrial fibrillation in the advent of the use of DOACs.

Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism

Embolism from the heart or the thoracic aorta often leads to clinically significant morbidity and mortality due to transient ischemic attack, stroke or occlusion of peripheral arteries. Transthoracic and transesophageal echocardiography are the key diagnostic modalities for evaluation, diagnosis, and management of stroke, systemic and pulmonary embolism. This document provides comprehensive American Society of Echocardiography guidelines on the use of echocardiography for evaluation of cardiac sources of embolism. It describes general mechanisms of stroke and systemic embolism; the specific role of cardiac and aortic sources in stroke, and systemic and pulmonary embolism; the role of echocardiography in evaluation, diagnosis, and management of cardiac and aortic sources of emboli including the incremental value of contrast and 3D echocardiography; and a brief description of alternative imaging techniques and their role in the evaluation of cardiac sources of emboli. Specific guidelines are provided for each category of embolic sources including the left atrium and left atrial appendage, left ventricle, heart valves, cardiac tumors, and thoracic aorta. In addition, there are recommendation regarding pulmonary embolism, and embolism related to cardiovascular surgery and percutaneous procedures. The guidelines also include a dedicated section on cardiac sources of embolism in pediatric populations.

Efficacy and Safety of Non-Vitamin K Antagonist Oral Anticoagulants After Cardioversion for Nonvalvular Atrial Fibrillation

BACKGROUND

Non-vitamin K oral anticoagulants (NOACs) are proven alternatives to vitamin K antagonists (VKAs) for the prevention of thromboembolism in patients with nonvalvular atrial fibrillation. However, there are few data on the efficacy and safety of NOAC therapy after cardioversion, where the risk of thromboembolic events is heightened.

METHODS

We performed a random-effects meta-analysis of patients who underwent both electrical and pharmacologic cardioversion for atrial fibrillation in the RE-LY, ROCKET-AF, ARISTOTLE, ENGAGE AF-TIMI 48, and X-VeRT trials. We assessed Mantel-Haenszel pooled estimates of risk ratio (RR) and 95% confidence intervals (CIs) for stroke/systemic embolism and major bleeding at ≤42 days of follow-up.

RESULTS

The analysis pooled 3949 patients in whom a total of 4900 cardioversions for atrial fibrillation were performed. Compared with VKAs, NOAC therapy was associated with a similar risk of stroke/systemic embolism (RR 0.84; 95% CI, 0.34-2.04) and major bleeding (RR 1.12; 95% CI, 0.52-2.42); no significant statistical heterogeneity was found among studies (Cochrane Q P = .59, I(2) = 0% for stroke/systemic embolism; P = .47; I(2) = 0% for major bleeding).

CONCLUSIONS

The short-term incidences of thromboembolic and major hemorrhagic events after cardioversion on NOACs were low and comparable to those observed on dose-adjusted VKA therapy. Non-vitamin K oral anticoagulants are a reasonable alternative to VKAs in patients undergoing cardioversion.

Low stroke risk after elective cardioversion of atrial fibrillation: an analysis of the Flec-SL trial

BACKGROUND

Current recommendations for anticoagulation management during cardioversion are largely based on historical data and expert consensus.

METHODS AND RESULTS

To characterize current practice of anticoagulation during and after elective cardioversion for AF and the risk of stroke and bleeding events, all patients enrolled into the Flec-SL trial were analyzed for stroke/transient ischemic attack and major bleeds after cardioversion. Flec-SL (ISRCTN62728743, NCT00215774) enrolled 635 patients (mean age 63.7 ± 10.9, 66% male). 629 (99.1%) patients received periprocedural anticoagulation, 556 (87.6%) were adequately anticoagulated following current recommendations. 202 (31.8%) patients underwent transesophageal echocardiography-guided cardioversion. Electrical cardioversion was used in 508 patients (80.0%), pharmacological cardioversion in 127 (20%). Six patients suffered from stroke (n = 5) or transient ischemic attack (3 TIAs in 1 patient, event rate 0.9%, 95% CI 0.4-2.1), five others from major bleeds (event rate 0.8%, 95% CI 0.3-1.9), consistent with the low reported event rates in prior studies. Three strokes occurred in the first 5 days after cardioversion. Events were independent of type of cardioversion or the use of TEE to exclude thrombi.

CONCLUSION

Strokes are rare in this large, prospectively followed cohort of patients undergoing cardioversion for AF and receiving antithrombotic therapy following local routine. These results support adherence to current recommendations for anticoagulation during cardioversion of AF.

Cardioversion under the guidance of transesophageal echochardiograhy in persistent atrial fibrillation: results with low molecular weight heparin

BACKGROUND

Transesophageal echocardiography (TEE) guided cardioversion to restoration of sinus rhythm is a therapeutic option in patients with atrial fibrillation (AF). Anticoagulation at the time of and after cardioversion is necessary to prevent formation of new thrombus during atrial stunning period. We aimed to evaluate the efficacy and safety to TEE guided cardioversion with low molecular weight heparin (LMWH) in patients with atrial fibrillation.

METHODS

We followed up 208 patients with persistent AF (mean age: 65.5+/-10.2 years) who were attempted TEE guided cardioversion. LMWH were used as an anticoagulant and warfarin therapy was continued.

RESULTS

Cardioversion were performed in 183 patients. Sinus rhythm restored in 144 patients (78.7%). Mean follow up duration was 155 days. No cardiac death occurred. In the early follow up period (within 30 day) one thromboembolic event (0.54%) occurred in a patient who was cardioverted. Two patients who had not been cardioverted because of left atrial thrombus presented embolic stroke, one in early and another in late follow up period. All embolic complications occurred in patients who had been taking warfarin and whose INR level was subtherapeutic at the time of stroke. Sinus rhythm was maintained in 64% and total hemorrhagic complications occurred in 4.8% of the patients in long-term follow-up.

CONCLUSION

TEE guided cardioversion with a short-term anticoagulation protocol using low molecular weight heparin is a safe and effective method in restoring and maintaining sinus rhythm and enables us to make earlier cardioversion in atrial fibrillation.

Efficacy of transesophageal echocardiography-guided cardioversion of patients with atrial fibrillation at 6 months: a randomized controlled trial

BACKGROUND

Electrical cardioversion in patients with atrial fibrillation (AF) is associated with an increased risk of stroke. We compared a transesophageal echocardiography (TEE)-guided strategy with a conventional strategy in patients with AF > 2 days' duration undergoing electrical cardioversion over a 6-month follow-up.

METHODS

The ACUTE study was a multicenter, randomized, clinical trial, with 1222 patients. Six-month follow-up was available in 1034 patients (85%), 525 in the TEE group and 509 in the conventional group. The primary composite end points were cerebrovascular accident, transient ischemic attack, and peripheral embolism at 6 months, which was a prespecified time point. Secondary end points were hemorrhage, mortality, and sinus rhythm.

RESULTS

At 6 months, there was no difference in composite embolic events between the TEE group and the conventional group (10 [2%] vs 4 [0.8%]; risk ratio (RR) 2.47, 95% CI 0.78-7.88; P = .11). However, the hemorrhagic rate was significantly lower in the TEE group (23 [4.4%] vs 38 [7.5%]; RR 0.58, 96% CI 0.35-0.97; P = .04). There was no difference between the 2 treatment groups in all-cause mortality (21 [4%] vs 14 [2.8%]; RR 1.48, 95% CI 0.76-2.92; P = .25) and in the occurrence of normal sinus rhythm between the 2 groups (305 [62.2%] vs 280 [58.1%]; P = .51). Sinus rhythm at 6 months was more common in the TEE-guided group, in those patients who had direct current cardioversion (238 [62.5%] vs 151 [53.9%]; P = .03).

CONCLUSION

The TEE-guided strategy may be considered a clinically effective alternative to a conventional anticoagulation strategy for patients with AF of > 2 days' duration undergoing electrical cardioversion over a 6-month period.

Pre- and post-cardioversion transesophageal echocardiography for brief anticoagulation therapy with enoxaparin in atrial fibrillation patients: a prospective study with a 1-year follow-up

BACKGROUND

In patients with atrial fibrillation (AF) eligible for electrical cardioversion (C), the guided approach with transesophageal echocardiography (TEE) allows to avoid the 3 weeks of recommended precardioversion anticoagulation therapy. However, after sinus rhythm restoration, at least other 4 weeks of oral anticoagulation therapy are indicated, due to the postcardioversion thromboembolic risk related to left atrial (LA) and left atrial appendage (LAA) stunning. The aim of this study was to prospectively assess the effectiveness and the safety of anticoagulation therapy discontinuation 7 days after C using low-molecular-weight heparins (LMWH) in a selected group of patients who underwent a pre-C and 7 days post-C TEE evaluation.

METHODS

One hundred one patients (74 patients with nonvalvular AF and 27 patients with atrial flutter lasting >48 h and history of AF) were enrolled into the study. Two patients refused the TEE, therefore, in 99/101, we performed a first TEE and, within 24 h, a C if there were no LAA thrombi, complex aortic plaques or severe spontaneous echocontrast. After C and 7 days of home-administered enoxaparin, a second TEE was carried out. In the absence of any new thrombi, severe spontaneous echocontrast and/or low emptying velocity of LAA, the therapy with enoxaparin was stopped; otherwise, anticoagulation therapy with enoxaparin was overlapped with oral anticoagulation and continued for at least 3 weeks. All patients were clinically followed at 1, 6 and 12 months after C.

RESULTS

Sinus rhythm was restored in 68/99 patients after successful C. The second TEE was carried out in 53 patients. At 1 month follow-up, no thromboembolic events were recorded either in patients at risk who had continued the oral anticoagulant therapy for at least 3 weeks or in those who suspended LMWH after 7 days post-C TEE. Between the 2nd and 12th month, three ischemic strokes occurred, all in the group of patients who had anticoagulation therapy for at least 3 weeks and had shown LAA velocity <25 cm/s at first or second TEE. No thromboembolic events were recorded in patients with normal LAA velocity; conversely, among the patients who had shown low LAA velocity at either TEE, three suffered from ischemic stroke. In two of these three patients, low LAA velocity was detected only at post-C TEE.

CONCLUSIONS

A brief anticoagulation therapy using LMWH appears to be safe and feasible. The 7 days post-C TEE can well-define patients without LAA stunning at low thromboembolic risk, who may take advantage of an early interruption of enoxaparin as an alternative to long oral anticoagulation. The LAA stunning, even in the absence of other thromboembolic risk factors, could select a group of patients at high risk who should continue oral anticoagulation indefinitely or until signs of LAA dysfunction disappear.

Prediction of Successful Cardioversion and Maintenance of Sinus Rhythm in Patients With Lone Atrial Fibrillation

OBJECTIVE

We aimed to prospectively investigate the predictive value of echocardiographic parameters for the prediction of successful cardioversion and long-term sinus rhythm (SR) maintenance in patients who have experienced a lone episode of atrial fibrillation (AF).

MEASUREMENTS AND RESULTS

Clinical and echocardiographic data, including mean left atrial appendage (LAA) peak flow velocity and mitral annulus motion, were analyzed in 78 consecutive patients (mean [+/- SD] age, 59.3 +/- 9.3 years) with AF lasting > 48 h and < 6 months. Sixty-one patients (78%) underwent successful external electrical cardioversion, while the remaining remained in AF. At the 1-year follow-up, of the 61 patients who had successfully been converted to SR, 24 (39.3%) remained in SR. For predicting the success of the cardioversion, we used a model consisting of two variables. LAA flow velocity (> 20 cm/s) and left ventricular (LV) fractional shortening (> 30%) appear to be quite strong, yielding 83.3% correct results. For predicting the maintenance of SR, we used a model consisting of two variables. The absence of the early systolic abnormal mitral annulus motion and LAA flow velocity (> 20 cm/s) appears to be quite strong, yielding 84.6% correct results. LAA flow velocity only marginally enters the model, and, if removed, little predictive value is lost (dropping to 83.3%). Removing the early systolic abnormal mitral annulus motion variable, the prediction value drops significantly to 70.5%.

CONCLUSION

LAA flow velocity combined with LV fractional shortening can predict the success of the conversion of AF to SR. Additionally, LAA flow velocity, combined with the analysis of mitral annulus motion before cardioversion, can predict the long-term maintenance of SR.

Antithrombotic Therapy in Valvular Heart Disease—Native and Prosthetic

This chapter about antithrombotic therapy in native and prosthetic valvular heart disease 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: For patients with rheumatic mitral valve disease and atrial fibrillation (AF), or a history of previous systemic embolism, we recommend long-term oral anticoagulant (OAC) therapy (target international normalized ratio [INR], 2.5; range, 2.0 to 3.0) [Grade 1C+]. For patients with rheumatic mitral valve disease with AF or a history of systemic embolism who suffer systemic embolism while receiving OACs at a therapeutic INR, we recommend adding aspirin, 75 to 100 mg/d (Grade 1C). For those patients unable to take aspirin, we recommend adding dipyridamole, 400 mg/d, or clopidogrel (Grade 1C). In people with mitral valve prolapse (MVP) without history of systemic embolism, unexplained transient ischemic attacks (TIAs), or AF, we recommended against any antithrombotic therapy (Grade 1C). In patients with MVP and documented but unexplained TIAs, we recommend long-term aspirin therapy, 50 to 162 mg/d (Grade 1A). For all patients with mechanical prosthetic heart valves, we recommend vitamin K antagonists (Grade 1C+). For patients with a St. Jude Medical (St. Paul, MN) bileaflet valve in the aortic position, we recommend a target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. For patients with tilting disk valves and bileaflet mechanical valves in the mitral position, we recommend a target INR of 3.0 (range, 2.5 to 3.5) [Grade 1C+]. For patients with caged ball or caged disk valves, we suggest a target INR of 3.0 (range, 2.5 to 3.5) in combination with aspirin, 75 to 100 mg/d (Grade 2A). For patients with bioprosthetic valves, we recommend vitamin K antagonists with a target INR of 2.5 (range, 2.0 to 3.0) for the first 3 months after valve insertion in the mitral position (Grade 1C+) and in the aortic position (Grade 2C). For patients with bioprosthetic valves who are in sinus rhythm and do not have AF, we recommend long-term (> 3 months) therapy with aspirin, 75 to 100 mg/d (Grade 1C+).

Economic analysis of a transesophageal echocardiography-guided approach to cardioversion of patients with atrial fibrillation

OBJECTIVES

The aim of this study was to compare the relative cost of a transesophageal echocardiography (TEE)-guided strategy versus conventional strategy for patients with atrial fibrillation (AF) >2 days duration undergoing electrical cardioversion over an eight-week period.

BACKGROUND

The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) trial found no difference in embolic rates between the two approaches. However, the TEE-guided strategy had a shorter time to cardioversion and a lower rate of composite bleeding. While similar clinical efficacy was concluded, the relative cost of these two strategies has not been explored.

METHODS

Two economic approaches were employed in the ACUTE trial. The first approach was based on hospital charge data from complete hospital Universal Billing Code of 1992 forms, a detailed hospital charge questionnaire, or imputation. Regression analysis was used to investigate the added cost of adverse events. The second economic approach involved the development of an independent analytic model simulating treatment and actual ACUTE outcome costs as a validation of clinically derived data. Sensitivity analysis was performed on the analytic model to investigate the potential range in cost differences between the strategies.

RESULTS

A total of 833 of the 1,222 patients were enrolled from 53 U.S. sites; TEE-guided (n = 420) and conventional (n = 413). At eight-week follow-up, total mean costs did not significantly differ between the two groups, respectively (6,508 dollars vs. 6,239 dollars; difference of 269 dollars; p = 0.50). Cumulative costs were 24% higher in the conventional group, primarily due to increased incidence of bleeding and hospital costs associated with bleeding. A separate analytic model showed that treatment costs were higher for the TEE-guided strategy, but outcome costs were higher for the conventional strategy. Sensitivity analysis of the analytic model illustrated that varying the incidence and cost of major bleeding and the cost of TEE had the greatest impact on cost differences between the two groups.

CONCLUSIONS

In patients with AF >2 days duration undergoing electrical cardioversion, the TEE-guided group showed little difference in patient costs compared with the conventional group. The TEE strategy had higher initial treatment costs but lower outcome-associated costs. Cumulative costs were 24% higher in the conventional group, primarily due to bleeding. The TEE-guided strategy is an economically feasible approach compared with the conventional strategy.

Use of transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation

BACKGROUND

The conventional treatment strategy for patients with atrial fibrillation who are to undergo electrical cardioversion is to prescribe warfarin for anticoagulation for three weeks before cardioversion. It has been proposed that if transesophageal echocardiography reveals no atrial thrombus, cardioversion may be performed safely after only a short period of anticoagulant therapy.

METHODS

In a multicenter, randomized, prospective clinical trial, we enrolled 1222 patients with atrial fibrillation of more than two days' duration and assigned them to either treatment guided by the findings on transesophageal echocardiography or conventional treatment. The composite primary end point was cerebrovascular accident, transient ischemic attack, and peripheral embolism within eight weeks. Secondary end points were functional status, successful restoration and maintenance of sinus rhythm, hemorrhage, and death.

RESULTS

There was no significant difference between the two treatment groups in the rate of embolic events (five embolic events among 619 patients in the transesophageal-echocardiography group [0.8 percent]) vs. three among 603 patients in the conventional-treatment group [0.5 percent], P=0.50). However, the rate of hemorrhagic events was significantly lower in the transesophageal-echocardiography group (18 events [2.9 percent] vs. 33 events [5.5 percent], P=0.03). Patients in the transesophageal-echocardiography group also had a shorter time to cardioversion (mean [+/-SD], 3.0+/-5.6 vs. 30.6+/-10.6 days, P<0.001) and a greater rate of successful restoration of sinus rhythm (440 patients [71.1 percent] vs. 393 patients [65.2 percent], P=0.03). At eight weeks, there were no significant differences between the two groups in the rates of death or maintenance of sinus rhythm or in functional status.

CONCLUSIONS

The use of transesophageal echocardiography to guide the management of atrial fibrillation may be considered a clinically effective alternative strategy to conventional therapy for patients in whom elective cardioversion is planned.

Role of transesophageal echocardiography-guided cardioversion of patients with atrial fibrillation

Electrical cardioversion of patients with atrial fibrillation (AF) is frequently performed to relieve symptoms and improve cardiac performance. Patients undergoing cardioversion are treated conventionally with therapeutic anticoagulation for three weeks before and four weeks after cardioversion to decrease the risk of thromboembolism. A transesophageal echocardiography (TEE)-guided strategy has been proposed as an alternative that may lower stroke and bleeding events. Patients without atrial cavity thrombus or atrial appendage thrombus by TEE are cardioverted on achievement of therapeutic anticoagulation, whereas cardioversion is delayed in higher risk patients with thrombus. The aim of this review is to discuss the issues and controversies associated with the management of patients with AF undergoing cardioversion. We provide an overview of the TEE-guided and conventional anticoagulation strategies in light of the recently completed Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) clinical trial. The two management strategies comparably lower the patient's embolic risk when the guidelines are properly followed. The TEE-guided strategy with shorter term anticoagulation may lower the incidence of bleeding complications and safely expedite early cardioversion. The inherent advantages and disadvantages of both strategies are presented. The TEE-guided approach with short-term anticoagulation is considered to be a safe and clinically effective alternative to the conventional approach, and it is advocated in patients in whom earlier cardioversion would be clinically beneficial.

Cost effectiveness of therapies for atrial fibrillation. A review

Atrial fibrillation is the most common supraventricular tachyarrhythmia encountered in clinical practice, affecting over 5% of persons over the age of 65 years. A common pathophysiological mechanism for arrhythmia development is atrial distention and fibrosis induced by hypertension, coronary artery disease or ventricular dysfunction. Less frequently, atrial fibrillation is caused by mitral stenosis or other provocative factors such as thyrotoxicosis, pericarditis or alcohol intoxication. Depending on the extent of associated cardiovascular disease, atrial fibrillation may produce haemodynamic compromise, or symptoms such as palpitations, fatigue, chest pain or dyspnoea. Arrhythmia-induced atrial stasis can precipitate clot formation and the potential for subsequent thromboembolism. Comprehensive management of atrial fibrillation requires a multifaceted approach directed at controlling symptoms, protecting the patient from ischaemic stroke or peripheral embolism and possible conversion to or maintenance of sinus rhythm. Numerous randomised trials have demonstrated the efficacy of warfarin--and less so aspirin (acetylsalicylic acid)--in reducing the risk of embolic events. Furthermore, therapeutic strategies exist that can favourably modify symptoms by restoring and maintaining sinus rhythm with cardioversion and antiarrhythmic prophylaxis. However, the risks and benefits of various treatments is highly dependent on patient-specific features, emphasising the need for an individualised approach. This article reviews the findings of cost-effectiveness studies published over the past decade that have evaluated different components of treatment strategies for atrial fibrillation. These studies demonstrate the economic attractiveness of acute management options, long term warfarin prophylaxis, telemetry-guided initiation of antiarrhythmic therapy, approaches to restore and maintain sinus rhythm, and the potential role of transoesophageal echocardiographic screening for atrial thrombus prior to pharmacological or electrical cardioversion. Further, we discuss the merits and limitations of the cost-effectiveness analyses in the context of overall treatment strategies. Finally, we identify areas that will require additional research to achieve the goal of effective and economically efficient management of atrial fibrillation.

Efficacy of anticoagulation in resolving left atrial and left atrial appendage thrombi: A transesophageal echocardiographic study

BACKGROUND

Transesophageal echocardiography (TEE) is the gold standard for evaluation of the left atrium and the left atrial appendage (LAA) for the presence of thrombi. Anticoagulation is conventionally used for patients with atrial fibrillation to prevent embolization of atrial thrombi. The mechanism of benefit and effectiveness of thrombi resolution with anticoagulation is not well defined.

METHODS AND RESULTS

We used a TEE database of 9058 consecutive studies performed between January 1996 and November 1998 to identify all patients with thrombi reported in the left atrium and/or LAA. One hundred seventy-four patients with thrombi in the left atrial cavity (LAC) and LAA were identified (1.9% of transesophageal studies performed). The incidence of LAA thrombi was 6.6 times higher than LAC thrombi (151 vs 23, respectively). Almost all LAC thrombi were visualized on transthoracic echocardiography (90.5%). Mitral valve pathology was associated with LAC location of thrombi (P <.0001), whereas atrial fibrillation or flutter was present in most patients with LAA location of thrombi. Anticoagulation of 47 +/- 18 days was associated with thrombus resolution in 80.1% of the patients on follow-up TEE. Further anticoagulation resulted in limited additional benefit.

CONCLUSIONS

LAC thrombi are rare and are usually associated with mitral valve pathology. Transthoracic echocardiography is effective in identifying these thrombi. LAA thrombi occur predominantly in patients with atrial fibrillation or flutter. Short-term anticoagulation achieves a high rate of resolution of LAA and LAC thrombi but does not obviate the need for follow-up TEE.

Transesophageal echocardiography-guided cardioversion of atrial fibrillation

Transesophageal echocardiography-guided anticoagulation management of patients with atrial fibrillation undergoing cardioversion has evolved over the past decade as a viable alternative to conventional anticoagulation management. Its use grew out of a need for a more predictable, dependable, and convenient approach to this difficult management dilemma, which has become increasingly prevalent in practice as an increasing number of patients present to clinics and hospitals with atrial fibrillation. In addition to its use in risk stratification of patients scheduled to undergo cardioversion, this management strategy allows for early cardioversion, which enables a minimal delay in proceeding from the diagnosis to the institution of therapy (electrical cardioversion). This review explores the evolution of the transesophageal echocardiography-guided strategy, the advantages and disadvantages of its use, and possible modifications to the strategy that would allow for a more convenient, practical, and more widely acceptable approach in the near future.

Structural remodeling of the left atrial appendage in patients with chronic non-valvular atrial fibrillation: Implications for thrombus formation, systemic embolism, and assessment by transesophageal echocardiography

Left atrial appendage (LAA) is frequently the site of thrombus formation in patients with chronic atrial fibrillation (AF). Transesophageal echocardiography and hematologic studies have identified blood flow stasis (spontaneous echogenic contrast) and abnormal coagulation (increased serum fibrinogen) as important predisposing factors to formation of LAA thrombi. However, the third component of the Virchow's triad, i.e., endothelial abnormalities, has not been adequately studied. Accordingly, we studied, at necropsy, the LAA morphology in 46 hearts of patients with (n = 22) and without (n = 24) chronic AF. Compared to patients without AF, those with AF had significantly larger LAA volumes (1.7% 1.1 vs. 5. 4% 3.7 mL, p = 0.0002), and larger luminal surface area of the bisected LAA (4.4% 1.8 vs. 7.1% 4.5 cm(2), p = 0.01). However, both the absolute and relative surface area of the transected pectinate muscles were reduced in patients with AF (2.6% 1.1 vs. 1.8% 1.0 cm(2), p = 0.02 and 38% 15 vs. 21% 14%, p = 0.0003). In addition, in most patients (73%) with chronic AF, the LAA showed significant endocardial thickening with fibrous and elastic tissue (endocardial fibroelastosis) compared to those without AF (13%, p < 0.0001). Endocardial fibroelastosis resulted in a smooth LAA luminal surface and encased the pectinate muscles. These findings suggest that LAA remodeling (dilation, stretching, and reduction in pectinate muscle volume, as well as endocardial fibroelastosis) occurs frequently in chronic AF and may contribute to the increased risk of thrombus formation and systemic embolism. Additionally, the information may have relevance in interpreting transesophageal echocardiographic images of the LAA in patients with chronic AF.

Management of the older person with atrial fibrillation

OBJECTIVE

To review the management of the older person with atrial fibrillation (AF).

DATA SOURCES

A computer-assisted search of the English language literature (MEDLINE) database followed by a manual search of the bibliographies of pertinent articles.

STUDY SELECTION

Studies on the management of persons with AF were screened for review. Studies of persons older than age 60 and recent studies were emphasized.

DATA EXTRACTION

Pertinent data were extracted from the reviewed articles. Emphasis was placed on studies involving older persons. Relevant articles were reviewed in depth.

DATA SYNTHESIS

Available data about the management of persons with paroxysmal or chronic AF were summarized

CONCLUSIONS

Management of AF includes treatment of the underlying disease and precipitating factors. Immediate direct-current cardioversion should be performed in persons with AF associated with an acute myocardial infarction, chest pain caused by myocardial ischemia, hypotension, severe heart failure, or syncope. Intravenous verapamil, diltiazem, or beta-blockers should be used to slow a very rapid ventricular rate associated with AF immediately. Oral verapamil, diltiazem, or a beta-blocker should be given if a rapid ventricular rate occurs at rest or during exercise despite digoxin. Amiodarone may be used in selected persons with symptomatic life-threatening AF refractory to other drug therapy. Nondrug therapies should be performed in persons with symptomatic AF in whom a rapid ventricular rate cannot be slowed by drug therapy. Paroxysmal AF associated with the tachycardia-bradycardia syndrome should be treated with a permanent pacemaker in combination with drugs. A permanent pacemaker should be implanted in persons with AF who develop cerebral symptoms such as dizziness or syncope associated with ventricular pauses greater than 3 seconds that are not drug-induced. Elective cardioversion of AF should not be performed in asymptomatic older persons with chronic AF. Unless transesophageal echocardiography has shown no thrombus in the left atrial appendage before cardioversion, oral warfarin should be given for 3 weeks before elective direct-current or drug cardioversion of AF and continued for at least 4 weeks after maintenance of sinus rhythm. Many cardiologists prefer the treatment strategy, especially in older persons, of ventricular rate control plus warfarin rather than maintaining sinus rhythm with antiarrhythmic drugs. Digoxin should be avoided in persons with sinus rhythm who have a history of paroxysmal AF. Older persons with chronic or paroxysmal AF who are at high risk for stroke or who have a history of hypertension and no contraindications to warfarin should receive long-term warfarin to achieve an International Normalized Ratio of 2.0 to 3.0. Older persons with AF who are at low risk for stroke or who have contraindications to warfarin should receive 325 mg of aspirin daily.

Atrial fibrillation trials: will they teach us what we need to know?

Atrial fibrillation (AF) has captured the imagination of clinical investigators who have initiated trials to examine several aspects of this multifaceted arrhythmia. We will review the protocol designs of ongoing trials that are examining the relative value of rhythm versus rate control, new methods for pharmacologic restoration and maintenance of sinus rhythm (including prophylaxis after cardiac surgery), and nonpharmacologic interventions such as pacing and atrial defibrillation. We antic ipate that the results of these studies will have a major impact on the care of patients with AF in the new millennium.

Assessment of Left Atrial Appendage Structure and Function by Transesophageal Echocardiography: A Review

This article examines the transesophageal echocardiographic assessment of the left atrial appendage anatomy and function in individuals without significant structural heart disease and in those with atrial fibrillation with or without cardioembolism or mitral valve stenosis. We also summarize the available data in the usefulness of transesophageal echocardiographic studies in patients undergoing cardioversion for atrial fibrillation and percutaneous balloon valvuloplasty for mitral stenosis. Also, potential limitations and ongoing developments in the use of transesophageal echocardiography in the assessment of the left atrial appendage are outlined, and recommendations are given for the uniform reporting of quantitative data.

Left atrial function is unchanged by implantable defibrillator shocks on hearts in sinus rhythm

Sixteen patients in sinus rhythm at baseline undergoing implantable cardioverter-defibrillator implantation were monitored with transesophageal echocardiography both before and after direct current cardioversion with currents of 15 to 20 J, for any direct current induced atrial dysfunction. We found no change in the indexes of atrial function or appearance of spontaneous echo contrast in the immediate postshock period by intraoperative transesophageal echocardiography.

Thromboembolic risks of left atrial thrombus detected by transesophageal echocardiogram

Patients with left atrial thrombus are considered at high risk for thromboembolic events. The actual prognosis of these patients and the features most predictive of future events are unclear. We performed transesophageal echocardiograms in 2,894 patients over a 6 1/2-year period; 94 (age 69 +/- 11 years, 59 men, 83 in atrial fibrillation) were found to have left atrial thrombus. The thrombi were considered mobile in 45 patients and 33 patients had thrombus with a maximum dimension > or = 1.5 cm. Seven of the 94 patients with prosthetic valves were excluded from follow-up analysis. Over a follow-up period of 25.3 +/- 19.2 months, 17 patients had suffered a stroke or embolic event (event rate 10.4% per year) and 27 had died (mortality 15.8% per year). Cox proportional hazard regression analysis identified a maximum thrombus dimension > or = 1.5 cm (RR 19, p = 0.002), history of thromboembolism (RR 4.2, p = 0.038), and mobile thrombus (RR 5.3, p = 0.02) as predictors of subsequent thromboembolism. Moderate or severe left ventricular dysfunction was the only significant predictor of death (RR 2.9, p = 0.04). Gender, age, warfarin therapy at follow-up, atrial fibrillation, location (cavity vs appendage) of thrombus, and spontaneous echocardiographic contrast were not significant. Aggressive antithrombotic therapy may be indicated in these high-risk patients.

Cost effectiveness of administration of intravenous anesthetics for direct-current cardioversion by nonanesthesiologists

Well-trained nonanesthesiologists can safely and effectively administer IV anesthetics for cardioversion. This practice results in considerable cost savings without compromising patient care.

Left atrial appendage "stunning" after electrical cardioversion of atrial flutter: an attenuated response compared with atrial fibrillation as the mechanism for lower susceptibility to thromboembolic events

OBJECTIVES

This study sought to determine whether left atrial appendage stunning occurs in patients with atrial flutter and to compare left atrial appendage function in the pericardioversion period with that in patients with atrial fibrillation.

BACKGROUND

Left atrial appendage stunning has recently been proposed as a key mechanistic phenomenon in the etiology of postcardioversion thromboembolic events in atrial fibrillation. Atrial flutter is thought to be associated with a negligible risk of thromboembolic events; therefore, anticoagulation is commonly withheld before and after cardioversion in these patients.

METHODS

Sixty-three patients with atrial flutter (n = 19) or atrial fibrillation (n = 44) underwent transesophageal echocardiography immediately before and after electrical cardioversion. In addition to assessing the presence of thrombus and spontaneous echo contrast, we measured left atrial appendage emptying velocity and calculated shear rates by pulsed wave Doppler and two-dimensional echocardiography.

RESULTS

Patients with atrial flutter exhibited greater left atrial appendage flow velocities before cardioversion than those with atrial fibrillation (42 +/- 19 vs. 28 +/- 15 cm/s [mean +/- SD], p < 0.001). Left atrial appendage shear rates were also higher in patients with atrial flutter (103 +/- 82 vs. 59 +/- 37 s-1, p < 0.001). After cardioversion, left atrial appendage flow velocities decreased compared with precardioversion values in patients with atrial fibrillation (28 +/- 15 before to 15 +/- 14 cm/s after cardioversion, p < 0.001) and atrial flutter (42 +/- 19 to 27 +/- 18 cm/s, respectively, p < 0.001). Shear rates decreased from 59 +/- 37 before cardioversion to 30 +/- 31 s-1 after cardioversion in atrial fibrillation (p < 0.001), and from 103 +/- 82 s to 65 +/- 52 s-1, respectively (p < 0.001), in atrial flutter. This decrease in flow velocity from before to after cardioversion occurred in 36 (82%) of 44 patients with atrial fibrillation and 14 (74%) of 19 with atrial flutter. The impaired left atrial appendage function after cardioversion was less pronounced in the group with atrial flutter (27 +/- 18 cm/s for atrial flutter vs. 15 +/- 14 cm/s for atrial fibrillation, p < 0.001). New or increased spontaneous echo contrast occurred in 22 (50%) of 44 patients with atrial fibrillation versus 4 (21%) of 19 with atrial flutter (p < 0.05).

CONCLUSIONS

Left atrial appendage stunning also occurs in patients with atrial flutter, although to a lesser degree than in those with atrial fibrillation. These data suggest that patients with atrial flutter are at risk for thromboembolic events after cardioversion, although this risk is most likely lower than that in patients with atrial fibrillation because of better preserved left atrial appendage function.

Transesophageal echocardiography-guided approach to cardioversion of atrial fibrillation

In patients with atrial fibrillation, electrical cardioversion is often performed to relieve symptoms, to improve left ventricular function, and to decrease thromboembolic risks. However, cardioversion of atrial tachyarrhythmias is associated with an increased embolic risk, with an event rate of up to 5.6%. The American College of Chest Physicians recommend 3 weeks of systemic anticoagulation before elective cardioversion and 4 weeks of systemic anticoagulation afterwards. Expulsion of preexisting left atrial (LA) thrombi with resumption of sinus rhythm has traditionally been considered the mechanism for this increased embolic risk associated with cardioversion. The advent of transesophageal echocardiography (TEE) has allowed accurate detection of LA thrombus. Moreover, recent studies using TEE have identified a state of atrial "stunning" immediately after cardioversion, which is considered a thrombogenic milieu in which new thrombus formation and increased or de novo appearance of LA spontaneous echocardiographic contrast have been observed. Furthermore, embolic events have been reported after cardioversion despite exclusion of preexisting LA thrombus by TEE. These studies strongly suggest an alternative mechanism for embolism after cardioversion, ie, atrial stunning with worsened atrial appendage function and enhanced thrombogenesis. Recent studies have shown the safety of a TEE-guided anticoagulation approach in which exclusion of preexisting LA thrombus by TEE enables early cardioversion without the need for the standard 3 weeks of systemic anticoagulation. The importance of maintaining therapeutic anticoagulation has been further emphasized. Although preliminary observational studies of TEE-guided cardioversion are encouraging, there has been no prospective, randomized trial comparing the two strategies of anticoagulation management. The Assessement of Cardioversion Utilizing Transesophageal Echocardiography (ACUTE) pilot study randomized 126 patients from 10 sites and showed the feasibility and safety of the larger scale study. A larger multicenter, prospective randomized trial is now underway and is expected to randomize a total of 3,000 patients. The results of the ACUTE study will definitively establish the safest and the most cost-effective way to manage anticoagulation for elective cardioversion.

Uncommon etiologies of atrial fibrillation

A newly diagnosed atrial fibrillation warrants a full investigation of the etiopathogenesis of this common arrhythmia. In the adult population, the most frequently associated conditions are systemic hypertension, coronary artery disease, mitral valvulopathy, congestive heart failure, and hyperthyroidism. Nevertheless, more infrequent and even rare, yet correctable, etiologies should not be overlooked. We describe three patients who presented to our hospital with a first episode of atrial fibrillation and who subsequently were demonstrated to have very unusual cardiovascular pathologies subtending this common arrhythmia. In all three cases, trans-esophageal echocardiography was instrumental in reaching an accurate diagnosis that was later confirmed at surgery.

Atrial Mechanical Function Before and After Electrical or Amiodarone Cardioversion in Atrial Fibrillation: Assessment by Transesophageal Echocardiography and Pulsed Doppler

In some patients with atrial fibrillation (AF), it has been suggested that left atrial mechanical dysfunction can develop after successful electrical cardioversion, justifying postcardioversion anticoagulant treatment. The purpose of this study was to investigate differences in left atrial appendage peak flow velocities and the incidence of left atrial spontaneous echo contrast in patients with AF before and after electrical cardioversion or intravenous amiodarone, studied using transesophageal echocardiography (TEE) and pulsed Doppler. We performed a control TEE in 7 patients in the electrical group and 6 in the amiodarone group, with no significant clinical differences between both groups. A second TEE was performed immediately in the 7 patients with successful electrical cardioversion. The peak flow velocities in the appendage before and after the procedure were: filling 43.3 +/- 22 vs 27.7 +/- 28 cm/sec (P = 0.01) and emptying 35.5 +/- 22 vs 23.6 +/- 17 cm/sec (P = 0.01), respectively. The spontaneous echo contrast increased in 4 of the 7 patients. In 4 patients of the amiodarone group, the peak flow velocities in the appendage during AF and within the first 24 hours after restoration of sinus rhythm were: filling 37.4 +/- 12 vs 37.8 +/- 18 cm/sec and emptying 36.4 +/- 18 vs 35.9 +/- 18 cm/sec, respectively (P = NS). There was no change in spontaneous echo contrast. In conclusion, patients with AF reverted to sinus rhythm using amiodarone did not show changes in left atrial mechanical function; however, patients with electrical cardioversion showed mechanical dysfunction. Further investigations on the effects of amiodarone and other drugs on the mechanical function of the atria are needed to determine if patients reverted pharmacologically require anticoagulation post reversion. (ECHOCARDIOGRAPHY, Volume 13, March 1996)

Newer developments in the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice. Unlike reentrant supraventricular tachycardia and malignant ventricular tachyarrhythmias, for which highly effective and safe nonpharmacologic therapies are available, the treatment of AF remains controversial and often problematic. Whereas electrical cardioversion restores sinus rhythm in most patients with AF, the maintenance of sinus rhythm often requires membrane-active antiarrhythmic drugs that may increase mortality by inducing ventricular proarrhythmia. The control of ventricular response rate, often associated with oral anticoagulation to prevent thromboembolic complications, is an alternative strategy in AF management. The relative efficacy and risks of these strategies and their respective role in different patient subgroups remain to be established. This article focuses on newer developments in the management of AF, including prospects for improved methods to maintain sinus rhythm, newer approaches to rate control, controversies regarding the use of oral anticoagulation, and novel nonpharmacologic therapies. These newer developments may lead over the next 10 years to a revolution in the management of AF as profound as that produced over the last 10 years by nonpharmacologic therapy of other arrhythmias.

Cardioversion of atrial fibrillation

Cardioversion to sinus rhythm should be considered for all patients in atrial fibrillation in order to improve cardiac performance and perhaps to reduce the long-term risk of thromboembolic complications. Different methods of cardioversion, whether electrical or pharmacological, exist and there is often uncertainty about performing the procedure. In particular, there is often confusion about the use of anti-arrhythmic drugs and the suitable length of anticoagulant therapy required pre- and post-cardioversion. This review discusses the current understanding of electrical and pharmacological cardioversion of atrial fibrillation, the clinical effects and the role of prophylactic anti-arrhythmic and anticoagulant therapy in this procedure.

Atrial fibrillation, transesophageal echo, electrical cardioversion, and anticoagulation

Although successful electrical cardioversion is accomplished in most cases without any evidence of embolic stroke, a few patients have experienced this catastrophe. The current thinking is that when electrical energy is applied to the chest wall, the atrium, although it returns to sinus rhythm, is stunned. It is not known how long this stunning lasts in the individual patient nor whether high energy produces stunning and low energy does not. Nor is it known whether chemical conversion of atrial fibrillation to sinus rhythm affects the atrium in the same way. However, the atrium seems to recover more quickly in patients with a short duration of atrial fibrillation and these patients may not require the usual four weeks of postcardioversion anticoagulation. Based on what we know, or more precisely what we don't know, it seems reasonable to ensure that every patient with atrial fibrillation is anticoagulated during and after DC cardioversion to sinus rhythm. Of course, this is easy to do with intravenous heparin, but that requires hospitalization. Perhaps subcutaneous heparin in high doses would suffice until the patient can be anticoagulated with coumadin. From the research perspective it might be interesting to perform serial echo/Doppler studies on these patients to identify when the individual patient's atrial function returns to normal. This might provide a clinical rationale for discontinuing anticoagulation. Comparing the time to return of normal atrial function (as measured by Doppler echo) between patients undergoing pharmacologic cardioversion versus electrical cardioversion and studying the relationship of the amount of electrical energy required for cardioversion versus the duration of stunning would be clinical research projects of interest to clinicians.