Functional capacity before and after cardioversion of atrial fibrillation: a controlled study

Use of Wearable Devices for Peak Oxygen Consumption Measurement in Clinical Cardiology: Case Report and Literature Review

BACKGROUND

Oxygen consumption is an important index to evaluate in cardiac patients, particularly those with heart failure, and is measured in the setting of advanced cardiopulmonary exercise testing. However, technological advances now allow for the estimation of this parameter in many consumer and medical-grade wearable devices, making it available for the medical provider at the initial evaluation of patients. We report a case of an apparently healthy male aged 40 years who presented for evaluation due to an Apple Watch (Apple Inc) notification of low cardiac fitness. This alert triggered a thorough workup, revealing a diagnosis of familial nonischemic cardiomyopathy with severely reduced left ventricular systolic function. While the use of wearable devices for the measurement of oxygen consumption and related parameters is promising, further studies are needed for validation.

OBJECTIVE

The aim of this report is to investigate the potential utility of wearable devices as a screening and risk stratification tool for cardiac fitness for the general population and those with increased cardiovascular risk, particularly through the measurement of peak oxygen consumption (VO2). We discuss the possible advantages of measuring oxygen consumption using wearables and propose its integration into routine patient evaluation and follow-up processes. With the current evidence and limitations, we encourage researchers and clinicians to explore bringing wearable devices into clinical practice.

METHODS

The case was identified at Sheba Medical Center, and the patient's cardiac fitness was monitored through an Apple Watch Series 6. The patient underwent a comprehensive cardiac workup following his presentation. Subsequently, we searched the literature for articles relating to the clinical utility of peak VO2 monitoring and available wearable devices.

RESULTS

The Apple Watch data provided by the patient demonstrated reduced peak VO2, a surrogate index for cardiac fitness, which improved after treatment initiation. A cardiological workup confirmed familial nonischemic cardiomyopathy with severely reduced left ventricular systolic function. A review of the literature revealed the potential clinical benefit of peak VO2 monitoring in both cardiac and noncardiac scenarios. Additionally, several devices on the market were identified that could allow for accurate oxygen consumption measurement; however, future studies and approval by the Food and Drug Administration (FDA) are still necessary.

CONCLUSIONS

This case report highlights the potential utility of peak VO2 measurements by wearable devices for early identification and screening of cardiac fitness for the general population and those at increased risk of cardiovascular disease. The integration of wearable devices into routine patient evaluation may allow for earlier presentation in the diagnostic workflow. Cardiac fitness can be serially measured using the wearable device, allowing for close monitoring of functional capacity parameters. Devices need to be used with caution, and further studies are warranted.

Dyspnea in patients with atrial fibrillation: Mechanisms, assessment and an interdisciplinary and integrated care approach

Atrial fibrillation (AF) is the most common sustained heart rhythm disorder and is often associated with symptoms that can significantly impact quality of life and daily functioning. Palpitations are the cardinal symptom of AF and many AF therapies are targeted towards relieving this symptom. However, up to two-third of patients also complain of dyspnea as a predominant self-reported symptom. In clinical practice it is often challenging to ascertain whether dyspnea represents an AF-related symptom or a symptom of concomitant cardiovascular and non-cardiovascular comorbidities, since common AF comorbidities such as heart failure and chronic obstructive pulmonary disease share similar symptoms. In addition, therapeutic approaches specifically targeting dyspnea have not been well validated. Thus, assessing and treating dyspnea can be difficult. This review describes the latest knowledge on the burden and pathophysiology of dyspnea in AF patients. We discuss the role of heart rhythm control interventions as well as the management of AF risk factors and comorbidities with the goal to achieve maximal relief of dyspnea. Given the different and often complex mechanistic pathways leading to dyspnea, dyspneic AF patients will likely profit from an integrated multidisciplinary approach to tackle all factors and mechanisms involved. Therefore, we propose an interdisciplinary and integrated care pathway for the work-up of dyspnea in AF patients.

Pharmacologic Rate versus Rhythm Control for Atrial Fibrillation in Heart Failure Patients

Atrial fibrillation (AF) and Heart failure (HF) constitute two frequently coexisting cardiovascular diseases, with a great volume of the scientific research referring to strategies and guidelines associated with the best management of patients suffering from either of the two or both of these entities. The common pathophysiological paths, the adverse outcomes, the hospitalization rates, and the mortality rates that occur from various reports and trials indicate that a targeted therapy to the common background of these cardiovascular conditions may reverse the progression of their interrelating development. Among other optimal treatments concerning the prevalence of both AF and HF, the introduction of rhythm and rate control strategies in the guidelines has underlined the importance of sinus rhythm and heart rate control in the prevention of deleterious complications. The use of these strategies in the clinical practice has led to a debate about the superiority of rhythm versus rate control. The current guidelines as well as the published randomized trials and studies have not proved that rhythm control is more beneficial than the rate control treatments in the terms of survival, all-cause mortality, hospitalization rates, and quality of life. Therefore, the current therapeutic strategy is based on the therapy guidelines and the clinical judgment and experience. The aim of this review was to elucidate the endpoints of pharmacologic randomized clinical trials and the clinical data of each antiarrhythmic or rate-limiting medication, so as to promote their effective, individualized, evidence-based clinical use.

Neurological complications of heart failure

Heart failure (HF) is a major global cause of death with increasing absolute worldwide numbers of HF patients. HF results from the interaction between cardiovascular aging with specific risk factors, comorbidities, and disease modifiers. The failing heart and neuronal injury have a bidirectional interaction requiring specific management strategies. Decreased cardiac output has been associated with lower brain volumes. Cerebral blood flow (CBF) may normalize following heart transplantation among severe HF patients. Stroke and cognitive impairment remain the main neurologic conditions associated with HF. However, HF patients may also suffer from chronic cerebral hypoperfusion. It seems likely that HF-related ischemic strokes are primarily the result of cardiac embolism. Atrial fibrillation (AF) is present in half of stroke patient with HF. The increased risk of hemorrhagic strokes is less well characterized and likely multifactorial, but may in part reflect a higher use of long-term antithrombotic therapy. The steady improvement of neuroimaging techniques has demonstrated an increased prevalence of silent ischemic lesions among HF patients. The populations most likely to benefit from long-term anticoagulant therapy are HF patients with AF. Cognitive impairment in HF can have a variety of clinical manifestations from mild memory problems to dementia.

WITHDRAWN: Electrical cardioversion for atrial fibrillation and flutter

BACKGROUND

Atrial fibrillation increases stroke risk and adversely affects cardiovascular haemodynamics. Electrical cardioversion may, by restoring sinus rhythm, improve cardiovascular haemodynamics, reduce the risk of stroke, and obviate the need for long-term anticoagulation.

OBJECTIVES

To assess the effects of electrical cardioversion of atrial fibrillation or flutter on the risk of thromboembolic events, strokes and mortality (primary outcomes), the rate of cognitive decline, quality of life, the use of anticoagulants and the risk of re-hospitalisation (secondary outcomes) in adults (>18 years).

SEARCH METHODS

We searched the Cochrane CENTRAL Register of Controlled Trials (1967 to May 2004), MEDLINE (1966 to May 2004), Embase (1980 to May 2004), CINAHL (1982 to May 2004), proceedings of the American College of Cardiology (published in Journal of the American College of Cardiology 1983 to 2003), www.trialscentral.org, www.controlled-trials.com and reference lists of articles. We hand-searched the indexes of the Proceedings of the British Cardiac Society published in British Heart Journal (1980 to 1995) and in Heart (1995 to 2002); proceedings of the European Congress of Cardiology and meetings of the Joint Working Groups of the European Society of Cardiology (published in European Heart Journal 1983-2003); scientific sessions of the American Heart Association (published in Circulation 1990-2003). Personal contact was made with experts.

SELECTION CRITERIA

Randomised controlled trial or controlled clinical trials of electrical cardioversion plus 'usual care' versus 'usual care' only, where 'usual care' included any combination of anticoagulants, antiplatelet drugs and drugs for 'rate control'. We excluded trials which used pharmacological cardioversion as the first intervention, and trials of new onset atrial fibrillation after cardiac surgery. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

For dichotomous data, odds ratios were calculated; and for continuous data, the weighted mean difference was calculated.

MAIN RESULTS

We found three completed trials of electrical cardioversion (rhythm control) versus rate control, recruiting a total of 927 participants (Hot Cafe; RACE; STAF) and one ongoing trial (J-RHYTHM). There was no difference in mortality between the two strategies (OR 0.83; CI 0.48 to 1.43). There was a trend towards more strokes in the rhythm control group (OR 1.9; 95% CI 0.99 to 3.64). At follow up, three domains of quality of life (physical functioning, physical role function and vitality) were significantly better in the rhythm control group (RACE 2002; STAF 2003).

AUTHORS' CONCLUSIONS

Electrical cardioversion (rhythm control) led to a non-significant increase in stroke risk but improved three domains of quality of life.

Impact of Atrial Fibrillation on Exercise Capacity and Mortality in Heart Failure With Preserved Ejection Fraction: Insights From Cardiopulmonary Stress Testing

Background

Atrial fibrillation (AF) has been objectively associated with exercise intolerance in patients with heart failure with reduced ejection fraction; however, its impact in patients with heart failure with preserved ejection fraction has not been fully scrutinized.

Methods and Results

We identified 1744 patients with heart failure and ejection fraction ≥50% referred for cardiopulmonary stress testing at the Cleveland Clinic (Cleveland, OH), 239 of whom had AF. We used inverse probability of treatment weighting to balance clinical characteristics between patients with and without AF. A weighted linear regression model, adjusted for unbalanced variables (age, sex, diagnosis, hypertension, and β‐blocker use), was used to compare metabolic stress parameters and 8‐year total mortality (social security index) between both groups. Weighted mean ejection fraction was 58±5.9% in the entire population. After adjusting for unbalanced weighted variables, patients with AF versus those without AF had lower mean peak oxygen consumption (18.5±6.2 versus 20.3±7.1 mL/kg per minute), oxygen pulse (12.4±4.3 versus 12.9±4.7 mL/beat), and circulatory power (2877±1402 versus 3351±1788 mm Hg·mL/kg per minute) (P<0.001 for all comparisons) but similar submaximal exercise capacity (oxygen consumption at anaerobic threshold, 12.0±5.1 versus 12.4±6.0mL/kg per minute; P =0.3). Both groups had similar peak heart rate, whereas mean peak systolic blood pressure was lower in the AF group (150±35 versus 160±51 mm Hg; P<0.001). Moreover, AF was associated with higher total mortality.

Conclusions

In the largest study of its kind, we demonstrate that AF is associated with peak exercise intolerance, impaired contractile reserve, and increased mortality in patients with heart failure with preserved ejection fraction. Whether AF is the primary offender in these patients or merely a bystander to worse diastolic function requires further investigation.

Usefulness of New-Onset Atrial Fibrillation, as a Strong Predictor of Heart Failure and Death in Patients With Native Left-Sided Infective Endocarditis

Atrial fibrillation (AF) is the most common cardiac arrhythmia in adults and has been independently related to increased morbidity and mortality. AF is a frequent arrhythmia in infective endocarditis (IE). Nevertheless, there are no data on how AF affects the clinical outcome of patients with endocarditis. Our purpose was to investigate patient characteristics, microbiology, echocardiographic findings, in-hospital course, and prognosis of patients with IE who develop new-onset AF (NAF) and compare them with those who remained in sinus rhythm (SR) or had previous AF (PAF). From 1997 to 2014, 507 consecutive patients with native left-sided IE were prospectively recruited at 3 tertiary care centers. We distinguished 3 groups according to the type of baseline heart rhythm during hospitalization and previous history of AF: NAF group (n = 52), patients with no previous history of AF and who were diagnosed as having NAF during hospitalization; SR group (n = 380), patients who remained in SR; and PAF group (n = 75), patients with PAF. Patients with NAF were older than those who remained in SR (68.3 vs 59.6 years, p <0.001). At admission, heart failure was more common in NAF group (53% vs 34.3%, p <0.001), whereas stroke (p = 0.427) was equally frequent in all groups. During hospitalization, embolic events occurred similarly (p = 0.411). In the multivariate analysis, NAF was independently associated with heart failure (odds ratio 3.56, p <0.01) and mortality (odds ratio 1.91, p = 0.04). In conclusion, the occurrence of NAF in patients with IE was strongly associated with heart failure and higher in-hospital mortality independently from other relevant clinical variables.

Real-time physiologic biomarker for prediction of atrial fibrillation recurrence, stroke, and mortality after electrical cardioversion: A prospective observational study

BACKGROUND

Left atrial appendage emptying flow velocity (LAAEV) depends largely on left atrioventricular compliance and may play a role in mediating the perpetuation of atrial fibrillation (AF) and AF-related outcomes.

METHODS

We identified 3,251 consecutive patients with sustained AF undergoing first-time successful transesophageal echocardiography (TEE)-guided electrical cardioversion who were enrolled in a prospective registry between May 2000 and March 2012. Left atrial appendage emptying flow velocity was stratified into quartiles: ≤20.2, 20.3-33.9, 34-49.9, and ≥50 cm/s. Multivariate Cox regression models were used to identify independent predictors of AF recurrence, ischemic stroke, and all-cause mortality.

RESULTS

The mean (SD) age was 69 (12.6) years and 67% were men. Compared with the fourth quartile, patients in the first-third quartiles were significantly older, had higher CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack [TIA], vascular disease, age 65-74 years, sex category) scores, greater frequency of atrial spontaneous echo contrast, and AF of longer duration. Kaplan-Meier analysis showed a decreased probability of event-free survival with decreasing quartiles of LAAEV. Five-year cumulative event rates across first-fourth quartiles were 83%, 80%, 73%, and 73% (P < .001) for first AF recurrence; 7.5%, 7.0%, 4.1%, and 4.0%, for stroke (P = .01); and 31.3%, 26.1%, 24.1%, and 19.4%, for mortality (P < .001), respectively. Multivariate Cox regression analysis revealed an independent association of the first and second quartiles with AF recurrence (P < .001 and P < .001, respectively) and stroke (P = .03, and P = .04, respectively), and of the first quartile with mortality (P = .003).

CONCLUSIONS

Patients with decreased LAAEV have an increased risk of AF recurrence, stroke, and mortality after successful electrical cardioversion. Real-time measurement of LAAEV by TEE may be a useful physiologic biomarker for individualizing treatment decisions in patients with AF.

Cardioversion of uncomplicated paroxysmal atrial fibrillation: a survey of practice by Canadian emergency physicians

Objective:

Paroxysmal atrial fibrillation (PAF) is the rhythm disturbance most commonly encountered by emergency physicians, yet the role played by emergency physicians in the management of this condition has not been well described. The purpose of this study was to describe the management of uncomplicated PAF by Canadian emergency physicians.

Methods:

All members of the Canadian Association of Emergency Physicians with a Canadian address (n = 1255) were mailed a 15-point questionnaire regarding training/certification, hospital demographics and practice patterns regarding the management of uncomplicated PAF. Chisquared analysis and Fisher’s Exact test were performed to identify significant differences in reported practice patterns in relation to demographic variables. Significant associations were tested for interaction using the Mantel–Haenszel test.

Results:

We received 663 responses, representing a 52.8% response rate. Six hundred and twenty-two (95%), 514 (78%) and 242 (38%) respondents reported routine performance of rate control, chemical cardioversion and electrical cardioversion respectively. Physicians working in high-volume emergency departments (&gt;50 000 visits/yr) were significantly more likely to self-manage rate control and chemical/electrical cardioversion than those working in lower volume emergency departments. Residency training was associated with higher performance of electrical (44% v. 31%, p &lt; 0.01) but not chemical cardioversion or rate control, although, amongst residency trained physicians, those with FRCP-level training were significantly more likely to perform both chemical (86% v. 76%, p &lt; 0.05) and electrical (57% v. 37%, p &lt; 0.01) cardioversion.

Conclusion:

Canadian emergency physicians surveyed in this study actively manage uncomplicated PAF. We found significant variations in practice, especially related to the use of electrical cardioversion. This may reflect different practice environments, levels of training, and lack of evidence to guide best practice. Further research is required to determine the optimal care of PAF in the emergency department setting.

Risk assessment for incident heart failure in individuals with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is a strong risk factor for heart failure (HF); HF onset in patients with AF is associated with increased morbidity and mortality. Risk factors that predict HF in individuals with AF in the community are not well established.

METHODS AND RESULTS

We examined clinical variables related to the 10-year incidence of HF in 725 individuals (mean 73.3 years, 45% women) with documented AF in the Framingham Heart Study. Event rates for incident HF (n = 161, 48% in women) were comparable in women (4.30 per 100 person-years) and men (3.34 per 100 person-years). Age, body mass index, ECG LV hypertrophy, diabetes, significant murmur, and history of myocardial infarction were positively associated with incident HF in multivariable models (C-statistic 0.71; 95% confidence interval 0.67-0.75). We developed a risk algorithm for estimating absolute risk of HF in AF patients with good model fit and calibration (adjusted calibration χ2 statistic 7.29; P(χ2) = 0.61). Applying the algorithm, 47.6% of HF events occurred in the top tertile in men compared with 13.1% in the bottom tertile, and 58.4% in women in the upper tertile compared with 18.2% in the lowest category. For HF type, women had a non-significantly higher incidence of HF with preserved EF compared with men.

CONCLUSIONS

We describe advancing age, LV hypertrophy, body mass index, diabetes, significant heart murmur, and history of myocardial infarction as clinical predictors of incident HF in individuals with AF. A risk algorithm may help identify individuals with AF at high risk of developing HF.

The effect of atrial fibrillation and the ventricular rate control on exercise capacity

BACKGROUND

Atrial fibrillation (AF) is a common cardiac arrhythmia, affecting approximately 1.5 million patients in the United States.

HYPOTHESIS

This study was designed to determine the effect of AF and the ventricular rate control during AF on cardiovascular performance as measured by exercise endurance on a standard Bruce protocol.

METHODS

Sixty-three patients with AF who underwent exercise stress testing during both sinus rhythm and AF were analyzed. Heart rate, blood pressure, heart rate acceleration, exercise duration, and left ventricular (LV) systolic function were measured.

RESULTS

Atrial fibrillation resulted in a small but statistically significant decrease in exercise endurance (426 +/- 180 vs. 402 +/- 168 s, p < 0.05). The drop in exercise tolerance was consistent regardless of the underlying heart condition or adequate ventricular rate control during AF. Heart rate in AF was consistently faster than in sinus rhythm, at rest, and at peak exercise (63 vs. 79 beats/min and 125 vs. 149 beats/min, respectively, p < 0.001).

CONCLUSION

Our analyses indicated that (1) the loss of atrioventricular synchrony had minimal effect on cardiovascular performance in patients with preserved LV function, (2) the decrease in cardiovascular performance was related to loss of atrioventricular synchrony but not to underlying heart disease or ventricular rate control, and (3) compensation for the loss of the atrial contribution was provided by consistently faster heart rate during AF.

Endothelial dysfunction and exercise performance in lone atrial fibrillation or associated with hypertension or diabetes: different results with cardioversion

Endothelial dysfunction and underperfusion of exercising muscle contribute to exercise intolerance, hyperventilation, and breathlessness in atrial fibrillation (AF). Cardioversion (CV) improves endothelial function and exercise performance. We examined whether CV is equally beneficial in diabetes and hypertension, diseases that cause endothelial dysfunction and are often associated with AF. Cardiopulmonary exercise and pulmonary and endothelial (brachial artery flow-mediated dilation) function were tested before and after CV in patients with AF alone ( n = 18, group 1) or AF with hypertension ( n = 19, group 2) or diabetes ( n = 19, group 3). Compared with group 1, peak exercise workload, O2 consumption (V̇o2), O2 pulse, aerobic efficiency (ΔV̇o2/ΔWR), and ratio of brachial diameter changes to flow changes (Δ D/ΔF) were reduced in group 2 and, to a greater extent, in group 3; exercise ventilation efficiency (V̇e/V̇co2 slope) and dead space-to-tidal volume ratio (Vd/Vt) were similar among groups. CV had less effect on peak workload (+7% vs. +18%), peak V̇o2 (+12% vs. +17%), O2 pulse (+33% vs. +50%), ΔV̇o2/ΔWR (+7% vs. +12%), V̇e/V̇co2 slope (−6% vs. −12%), Δ D/ΔF (+7% vs. +10%), and breathlessness (Borg scale) in group 2 than in group 1 and was ineffective in group 3. The antioxidant vitamin C, tested in eight additional patients in each cohort, improved flow-mediated dilation in groups 1 and 2 before, but not after, CV and was ineffective in group 3, suggesting that the oxidative injury is least in lone AF, greater in hypertension with AF, and greater still in diabetes with AF. Comorbidities that impair endothelial activity worsen endothelial dysfunction and exercise intolerance in AF. The advantages of CV appear to be inversely related to the extent of the underlying oxidative injury.

Comparison of rate control and rhythm control in patients with atrial fibrillation after percutaneous mitral balloon valvotomy: a randomised controlled study

OBJECTIVE

To compare rate control and rhythm control strategies in patients with atrial fibrillation (AF) after percutaneous mitral balloon valvotomy (PMV).

METHODS

183 patients with AF after successful PMV, with AF duration <or= 12 months and post-PMV left atrial (LA) size <or= 45 mm, were studied in a prospective, randomised trial. The primary end point was improvement in AF-related symptoms. Secondary study end points were 6 min walk tests, quality of life (QOL), normalisation of LA size, number of hospital admissions and duration of hospital stay.

RESULTS

Over one year, 2% patients in the rate control group had sinus rhythm, as compared with 96% of patients in the rhythm control group (p < 0.001). A greater proportion of patients reported improvement in symptoms in the rhythm control group than in the rate control group (p < 0.0001 at every visit time). Walking distance in a 6 min walk test, QOL and LA size normalisation were better in the rhythm control group than in the rate control group. The strategy of rhythm control was associated with similar numbers of hospital admissions but with longer duration of hospital admissions. Drug-related side effect did not differ between the rate control and rhythm control groups. During the follow-up period, no patients in either group had embolic or transitory ischaemic neurological events.

CONCLUSIONS

In patients with AF after PMV, AF duration <or= 12 months and post-PMV LA size <or= 45 mm, sinus rhythm was easy and safe to achieve and maintain. Moreover, patients benefited from restoration and maintenance of sinus rhythm in terms of improved AF-related symptoms, 6 min walk tests and QOL, and of LA size normalisation. Rhythm control should therefore be considered as the preferred initial therapy for this group of patients. The optimal strategy to treat AF after PMV should be individualised.

Electrical cardioversion for atrial fibrillation and flutter

BACKGROUND

Atrial fibrillation increases stroke risk and adversely affects cardiovascular haemodynamics. Electrical cardioversion may, by restoring sinus rhythm, improve cardiovascular haemodynamics, reduce the risk of stroke, and obviate the need for long-term anticoagulation.

OBJECTIVES

To assess the effects of electrical cardioversion of atrial fibrillation or flutter on the risk of thromboembolic events, strokes and mortality (primary outcomes), the rate of cognitive decline, quality of life, the use of anticoagulants and the risk of re-hospitalisation (secondary outcomes) in adults (>18 years).

SEARCH STRATEGY

We searched the Cochrane CENTRAL Register of Controlled Trials (1967 to May 2004), MEDLINE (1966 to May 2004), Embase (1980 to May 2004), CINAHL (1982 to May 2004), proceedings of the American College of Cardiology (published in Journal of the American College of Cardiology 1983 to 2003), www.trialscentral.org, www.controlled-trials.com and reference lists of articles. We hand-searched the indexes of the Proceedings of the British Cardiac Society published in British Heart Journal (1980 to 1995) and in Heart (1995 to 2002); proceedings of the European Congress of Cardiology and meetings of the Joint Working Groups of the European Society of Cardiology (published in European Heart Journal 1983-2003); scientific sessions of the American Heart Association (published in Circulation 1990-2003). Personal contact was made with experts.

SELECTION CRITERIA

Randomised controlled trial or controlled clinical trials of electrical cardioversion plus 'usual care' versus 'usual care' only, where 'usual care' included any combination of anticoagulants, antiplatelet drugs and drugs for 'rate control'. We excluded trials which used pharmacological cardioversion as the first intervention, and trials of new onset atrial fibrillation after cardiac surgery. There were no language restrictions.

DATA COLLECTION AND ANALYSIS

For dichotomous data, odds ratios were calculated; and for continuous data, the weighted mean difference was calculated.

MAIN RESULTS

We found three completed trials of electrical cardioversion (rhythm control) versus rate control, recruiting a total of 927 participants (Hot Cafe; RACE; STAF) and one ongoing trial (J-RHYTHM). There was no difference in mortality between the two strategies (OR 0.83; CI 0.48 to 1.43). There was a trend towards more strokes in the rhythm control group (OR 1.9; 95% CI 0.99 to 3.64). At follow up, three domains of quality of life (physical functioning, physical role function and vitality) were significantly better in the rhythm control group (RACE 2002; STAF 2003).

AUTHORS' CONCLUSIONS

Electrical cardioversion (rhythm control) led to a non-significant increase in stroke risk but improved three domains of quality of life.

Rate versus Rhythm Control in Patients with Atrial Fibrillation

Despite new insights into the pathophysiological triggers of atrial fibrillation (AF) and the development of novel ablative techniques and antiarrhythmic drugs, the management of this chronic rhythm disturbance remains problematic. At present, there are two fundamental interventional choices: restoration and maintenance of normal sinus rhythm (NSR) or control of the ventricular rate. While there are compelling theoretical benefits in restoring and maintaining NSR, until recently there has been little evidence supporting the comparative advantages of either strategy. During the past few years, five randomised trials investigating the two treatment strategies have been completed: PIAF (Pharmacological Intervention in Atrial Fibrillation), STAF (Strategies of Treatment of Atrial Fibrillation), RACE (RAte Control versus Electrical conversion), AFFIRM (Atrial Fibrillation Follow-up of Rhythm Management) and HOT-CAFE (How to Treat Chronic Atrial Fibrillation). Results from these studies indicate that a strategy of rate control in AF patients can be at least as effective as efforts to control rhythm with respect to several specific outcomes. These trials have also revealed the necessity of continuing antithrombotic treatment even when long-term sinus rhythm is obtained. However, these trials had different patient selection criteria, endpoints and therapeutic interventions, limiting the applicability of their findings to all AF populations. This article looks beyond the primary results from these important studies, using recent substudy analyses to draw new conclusions and to generate hypotheses that will require prospective evaluation in adequately powered trials. One substudy suggested, for instance, that failure of rhythm control to show superiority may be a result of the toxicity of current antiarrhythmic drugs. New class III compounds with novel mechanisms are now in varying stages of clinical development. These drugs appear to block multiple membrane ion channels, with predominant effects on the atria and low proarrhythmic potential. It is anticipated that these agents will be safer than, and at least as effective as, currently available drugs, thereby reducing AF-related morbidity and mortality. Until more effective treatments are available, physicians should use the evidence generated from the major studies to guide decision making based upon the characteristics and symptomatic presentation of individual patients.

Rate control vs rhythm control in patients with nonvalvular persistent atrial fibrillation: the results of the Polish How to Treat Chronic Atrial Fibrillation (HOT CAFE) Study

STUDY OBJECTIVES

The relative risks and benefits of strategies of rate control vs rhythm control in patients with atrial fibrillation (AF) remain to be fully explored.

DESIGN

The How to Treat Chronic Atrial Fibrillation (HOT CAFE) Polish trial was designed to evaluate in a randomized, multicenter, and prospective manner the feasibility and long-term outcomes of rate control vs rhythm control strategies in patients with persistent AF.

PATIENTS

Our study population comprised 205 patients (134 men and 71 women; mean [+/- SD] age, 60.8 +/- 11.2 years) with a mean AF duration of 273.7 +/- 112.4 days. The mean observation period was 1.7 +/- 0.4 years. One hundred one patients were randomly assigned to the rate control group and received rate-slowing therapy guided by repeated 24-h Holter monitoring. Direct current cardioversion and atrioventricular junctional ablation with pacemaker placement were alternative nonpharmacologic strategies for patients with tachycardia that was resistant to medical therapy. One hundred four patients were randomized to sinus rhythm restoration and maintenance using serial cardioversion supported by a predefined stepwise antiarrhythmic drug regimen (ie, disopyramide, propafenone, sotalol, and amiodarone). In both groups, thromboembolic prophylaxis followed current guidelines.

MEASUREMENTS AND RESULTS

At the end of follow-up, 63.5% of patients in the rhythm control arm remained in sinus rhythm. No significant differences in the composite end point (ie, all-cause mortality, number of thromboembolic events, or major bleeding) were found between the rate control group and the rhythm control group (odds ratio, 1.98; 95% confidence interval, 0.28 to 22.3; p > 0.71). The incidence of hospital admissions was much lower in the rate control arm (12% vs 74%, respectively; p < 0.001). New York Heart Association functional class improved in both study groups, while mean exercise tolerance, as measured by the maximal treadmill workload, improved only in the rhythm control group (5.2 +/- 5.1 vs 7.6 +/- 3.3 metabolic equivalents, respectively; p < 0.001). The rhythm control strategy led to an increased mean left ventricular fractional shortening (29 +/- 7% vs 31 +/- 7%, respectively; p < 0.01). One episode of pulmonary embolism occurred in the rate control group despite oral anticoagulation therapy, while three patients in the rhythm control arm of the study experienced ischemic strokes (not significant).

CONCLUSIONS

The Polish HOT CAFE study revealed no significant differences in major end points between the rate control group and the rhythm control group.

Exercise hyperventilation, dyspnea sensation, and ergoreflex activation in lone atrial fibrillation

Lone atrial fibrillation may be associated with daily life disability and exercise limitation. The extracardiac pathophysiology of these effects is poorly explored. In 35 subjects with lone atrial fibrillation (mean age 67 +/- 7 yr), we investigated pulmonary function, symptom-limited cardiopulmonary exercise performance, muscle ergoreflex (handgrip exercise) contribution to ventilation, and brachial artery flow-mediated dilation (as a measure of endothelial function) before and after (average interval 20 +/- 5 days) restoring sinus rhythm with external cardioversion. Respiratory volumes and lung diffusing capacity at rest were within normal limits during both atrial fibrillation and after restoring sinus rhythm. Cardioversion was associated with the following changes: a decrease of the slope of exercise ventilation vs. CO2 production (from 35 +/- 5 to 29 +/- 3; P <0.01) and of dyspnea sensation (Borg score from 4 to 2) and an increase of peak oxygen uptake (Vo2; from 16 +/- 4 to 20 +/- 5 ml.min(-1).kg(-1); P <0.01), Vo2 at anaerobic threshold (from 11 +/- 2 to 13 +/- 2 ml.min(-1).kg(-1); P <0.05), and O2 pulse (from 8 +/- 3 to 11 +/- 3 ml/beat; P <0.01). After cardioversion, the observed improvement in ventilatory efficiency was accompanied by a significant peak end-tidal CO2 increase (from 33 +/- 2 to 37 +/- 2 mmHg; P <0.01) and no changes in dead space-to-tidal volume ratio (from 0.23 +/- 0.03 to 0.23 +/- 0.02; P=not significant). In addition, the ergoreflex contribution to ventilation was remarkably attenuated, and the brachial artery flow-mediated dilatation was significantly augmented (from 0.32 +/- 0.07 to 0.42 +/- 0.08 mm; P <0.01). Ten patients had atrial fibrillation relapse and, compared with values after restoration of regular sinus rhythm, invariably showed worsening of endothelial function, exercise ventilatory efficiency, and muscle ergoreflex contribution to ventilation. In subjects with lone atrial fibrillation, an impairment in ventilatory efficiency appears to be involved in the pathophysiology of exercise limitation, and to be primarily related with a demodulated peripheral control of ventilation.

REDUCED HIGH SERUM HEPATOCYTE GROWTH FACTOR LEVELS AFTER SUCCESSFUL CARDIOVERSION IN PATIENTS WITH ATRIAL FIBRILLATION

1. Serum hepatocyte growth factor (HGF) is considered to be a potent marker of vascular endothelial injury. The present study was designed to examine serum HGF levels in atrial fibrillation and after successful direct current (DC) cardioversion. 2. We measured serum HGF levels before and 7 days and 1 month after DC cardioversion in 39 patients with atrial fibrillation in whom sinus rhythm was maintained for at least 7 days after DC cardioversion and in 30 age- and sex-matched normal control subjects with sinus rhythm. We also measured acetylcholine-induced changes in forearm blood flow (FBF) using venous occlusive plethysmography in 10 patients. 3. Serum HGF levels were significantly higher in the atrial fibrillation patients (both lone atrial fibrillation and with underlying heart disease) than in the controls (0.16 +/- 0.07 vs 0.10 +/- 0.04 ng/mL; P < 0.001). Seven days after successful DC cardioversion, the patients' serum HGF levels had decreased significantly (0.16 +/- 0.07 vs 0.12 +/- 0.06 ng/mL; P < 0.05) and in the 24 patients maintaining sinus rhythm 1 month after DC cardioversion, serum HGF levels decreased to control values (0.10 +/- 0.08 ng/mL at 1 month). Serum HGF levels of the 15 patients who had relapsed into atrial fibrillation 1 month after DC cardioversion tended to decrease 7 days after DC cardioversion, but increased again 1 month after DC cardioversion. Percentage changes in FBF between baseline and the highest dose of acetylcholine before and after DC cardioversion were 180 +/- 98 and 323 +/- 196%, respectively (P = 0.0051). The rate of increase in FBF at the highest dose of acetylcholine between before and after DC cardioversion correlated negatively with the rate of decrease in serum HGF levels between before and after DC cardioversion (r = -0.837; P = 0.0025). 4. This study is the first to demonstrate that serum HGF levels increase in atrial fibrillation and decrease after successful DC cardioversion. This may reflect the fact that atrial fibrillation induces vascular endothelial injury.

Implications for Nursing Care of Patients With Atrial Fibrillation

Atrial fibrillation is the most common sustained cardiac dysrhythmia treated in North America and Europe. As such, it is one of the current epidemics in cardiovascular disease. Findings from the AFFIRM (Atrial Fibrillation Follow-up: Investigation of Rhythm Management) and RACE (RAte Control versus Electrical cardioversion for persistent atrial fibrillation) clinical trials are presented and the current evidence for the management of atrial fibrillation using anticoagulation, rate-control, and rhythm-control strategies is outlined. Implications for nurses are discussed including physiologic and psychosocial interventions.

Heart Failure in the Elderly

Incidence and prevalence of heart failure are particularly common with advancing age, with notoriously grim prognoses. The absolute number of heart failure patients will undoubtedly surge as the population of older adults continues to escalate. This review emphasizes the importance of factors inherent in aging itself and the resulting predisposition to disease. Physiologic changes associated with cardiovascular aging fundamentally increase susceptibility to heart failure and to complexity of heart failure management. Likewise, typical age-associated diet and lifestyle changes compound risks of heart failure through mechanisms connected to the substrate of disease. In this review, the authors first summarize the demographics of heart failure and the intrinsic aspects of aging and lifestyle that predispose to heart failure. They then expand on related intricacies of diagnosis and therapy. Orientation to heart failure, particularly as a disease of aging, can help critically refine management of acute and chronic disease, as well as foster preventive strategies to reduce incidence of this common malady.

Heart failure complicated by atrial fibrillation: mechanistic, prognostic, and therapeutic implications

Atrial fibrillation and congestive heart failure are two distinct clinical entities that are responsible for significant morbidity and mortality in the Western world. Hypertension, coronary artery disease, and nonischemic cardiomyopathy represent the most prevalent underlying pathologies of both diseases, implying a coincidence of both in many patients. The prevalence of atrial fibrillation with a progressive degree of congestive heart failure is increasing, as judged by New York Heart Association functional class. Moreover, the presence of congestive heart failure has been identified as one of the most powerful independent predictors of atrial fibrillation, with a sixfold increase in relative risk of its development. On the other hand, atrial fibrillation can cause or significantly aggravate symptoms of congestive heart failure in previously asymptomatic or well-compensated patients. In some patients, symptomatic dilated cardiomyopathy may develop over time entirely due to atrial fibrillation with rapid ventricular rates. Upon restoration of sinus rhythm, this type of "tachymyopathy" has been shown to be often reversible. Recent investigations of the physiologic and structural changes of the atrial myocardium ("electrical and structural remodeling") have shown that neurohumoral activation, fibrosis, and apoptosis are demonstrable with both diseases. On the other hand, experimental data suggest that the substrates of atrial fibrillation in congestive heart failure are different from those of pure atrial tachycardia-related forms of atrial fibrillation. This review highlights the clinical and pathophysiologic similarities and differences of atrial fibrillation and congestive heart failure relevant to the understanding, treatment, and prevention of these diseases in the population at risk.

Safety of electrical cardioversion in patients with atrial fibrillation

OBJECTIVES

To determine the incidence of thromboembolic complications after electively performed electrical cardioversion in patients with atrial fibrillation and to assess the clinical variables associated with an increased risk of thromboembolism after cardioversion.

PATIENTS AND METHODS

This is a retrospective analysis of 834 successful electrical cardioversions performed in 717 patients from 1990 through 1994. Outcome measures included embolic complications at 1-month follow-up after cardioversion and logistic regression models to measure the associations among clinical, anticoagulation, and thromboembolic events and to identify independent predictors of these events.

RESULTS

The rate of embolic events after cardioversion was low (0.9%; 95% confidence interval, 0.4%-1.8%). Patients with a therapeutic international normalized ratio had no embolic events. Adequate anticoagulation was independently associated with reduced risk of thromboembolism. Hypertension and diabetes mellitus were independently associated with increased risk of embolization.

CONCLUSION

Adequate anticoagulation reduced the risk of embolization after cardioversion. Diabetes mellitus and hypertension are independently associated with increased risk of embolization early after cardioversion.

Anti-thrombotic strategies for patients with atrial fibrillation and heart failure

Atrial fibrillation occurs commonly in the setting of congestive heart failure and, in fact can cause left ventricular dysfunction due to a rapid ventricular response over time, termed tachycardia-mediated cardiomyopathy. The combination of atrial fibrillation and congestive heart failure leads to a high risk of stroke for the patient and appropriate antithrombotic therapy can minimize this incidence of stroke. Stroke risk can be markedly reduced by treatment with warfarin and complications of anticoagulation minimized by close attention to maintaining the INR between 2.0 and 3.0.

Prevention of and medical therapy for atrial arrhythmias in heart failure

A large proportion of heart failure patients suffer from atrial arrhythmias, prime amongst them being atrial fibrillation (AF). Ventricular dysfunction and the syndrome of heart failure can also be a concomitant pathology in up to 50% of patients with AF. However this association is more than just due to shared risk factors, research from animal and human studies suggest a causal relationship between AF and heart failure. There are numerous reports of tachycardia-induced heart failure where uncontrolled ventricular rate in AF results in heart failure, which is reversible with cardioversion to sinus rhythm or ventricular rate control. However the relationship extends beyond tachycardia-induced cardiomyopathy. Optimal treatment of AF may delay progressive ventricular dysfunction and the onset of heart failure whilst improved management of heart failure can prevent AF or improve ventricular rate control. Prevention and treatment of atrial arrhythmias, and in particular atrial fibrillation, is therefore an important aspect of the management of patients with heart failure. This review describes the incidence and possible predictors of AF and other atrial arrhythmias in patients with heart failure and discusses the feasibility of primary prevention. The evidence for the management of atrial fibrillation in heart failure is systematically reviewed and the strategies of rate versus rhythm control discussed in light of the prevailing evidence.

Twenty-four-hour ambulatory blood pressure monitoring in atrial fibrillation

BACKGROUND

Due to large beat-to-beat blood pressure variation the use of 24-h ambulatory blood pressure monitoring in patients with atrial fibrillation has been questioned.

METHODS

Repeatability and variability of 24-h ambulatory blood pressure (Accutraccer II or Diasys Integra), and daily blood pressure variation was examined in 42 patients aged 51-81 (median 73.5) years admitted for elective electrocardioversion of atrial fibrillation.

RESULTS

Before cardioversion 24-h ambulatory systolic blood pressure was slightly lower and nocturnal blood pressure reduction was larger in the group of patients who achieved sinus rhythm than in the group who maintained atrial fibrillation (11.5/10.5 versus 4.1/4.7 mmHg; P < 0.05). No statistically significant change was observed in ambulatory blood pressure after cardioversion in any of the two groups. Blood pressure variability (SD/mean) was 10-14% both in patients with and without conversion to sinus rhythm. Coefficient of repeatability (2 SD of difference) was 13.6 mmHg (16.6%) for diastolic blood pressure and 30.2 mmHg (24.7%) for systolic blood pressure in patients with normalized heart rhythm and 17.0 and 29.0 mmHg (21.5 and 22.4%) in patients with maintained atrial fibrillation, respectively.

CONCLUSION

Ambulatory blood pressure monitoring provides data with similar variability and repeatability in patients with atrial fibrillation as in subjects with normal cardiac rhythm. Twenty-four-hour ambulatory blood pressure measurement is applicable in atrial fibrillation in the same way as during sinus rhythm.

Atrial fibrillation: strategies to control, combat, and cure

Atrial fibrillation is the commonest clinical arrhythmia, is increasing in incidence and prevalence, and is associated with substantial morbidity and mortality. The arrhythmia may be paroxysmal (self-limiting), persistent (amenable to cardioversion), or permanent. Especially in its paroxysmal form, atrial fibrillation may be initiated by rapidly firing foci, generally located in the proximal pulmonary veins. Sustained atrial fibrillation is maintained by an atrial tissue substrate capable of accommodating many meandering wavelets. With continuing arrhythmia, the electrophysiological properties of the atria change and further facilitate continuing fibrillation. Treatment is aimed at prevention of thromboembolic complications, restoration and maintenance of sinus rhythm, and control of ventricular rate during atrial fibrillation. With greater understanding of the arrhythmia mechanisms, it is becoming possible to offer targeted curative treatments to more and more patients.

Electrical cardioversion for atrial fibrillation and flutter

BACKGROUND

Atrial fibrillation increases the risk of stroke, increases the risk of cognitive impairment, and adversely affects cardiovascular haemodynamics. Electrical cardioversion for atrial fibrillation has been in use since the 1960s; the rationale is that restoration of sinus rhythm improves cardiovascular haemodynamics, reduces the risk of stroke, and obviates the need for long-term anticoagulation.

OBJECTIVES

To assess the effects of electrical cardioversion of atrial fibrillation or atrial flutter on the annual risk of thromboembolic events, strokes and mortality (primary outcomes measures), the rate of cognitive decline, quality of life, the use of anticoagulants and the risk of re-hospitalisation (secondary outcome measures) in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and any aetiology.

SEARCH STRATEGY

One reviewer searched the Cochrane Controlled Clinical Trials Register (2000 Issue 4), MEDLINE (1966 to December 2000), EMBASE (1980 to December 2000), CINAHL (1982 to November 2000) and proceedings of the American College of Cardiology (published in the Journal of the American College of Cardiology 1983 to 2000). Reference lists of articles were searched. Personal contact was made with experts in the field. A second reviewer handsearched proceedings of the British Cardiac Society (published in British Heart Journal (1980 to 1995) and in Heart (1995 to May 2001); proceedings of the European Congress of Cardiology and meetings of the Joint Working Groups of the European Society of Cardiology (published in European Heart Journal 1983-2000); scientific sessions of the American Heart Association (published in Circulation 1990-2000).

SELECTION CRITERIA

Randomised controlled trial or controlled clinical trials of electrical cardioversion plus 'usual care' versus 'usual care' only, where 'usual care' included any combination of the following: anticoagulants, antiplatelet drugs and drugs for 'rate control', in adults (>18 years) with acute, paroxysmal or sustained atrial fibrillation or atrial flutter, of any duration and any aetiology.

DATA COLLECTION AND ANALYSIS

It was planned to extract study data onto data extraction forms. The planned analysis was by the statistical package in RevMan.

MAIN RESULTS

No completed randomised trials or controlled clinical trials of electrical cardioversion were found. Two ongoing trials were identified.

REVIEWER'S CONCLUSIONS

There were no data from completed randomised controlled trials or controlled clinical trials to either support or refute the use of electrical cardioversion for atrial fibrillation. Randomised trials of electrical cardioversion are required.

Electrical cardioversion for atrial fibrillation: outcomes in "real-life" clinical practice

BACKGROUND

There is currently considerable debate with regard to the optimal management of atrial fibrillation/flutter (AF), including the long-term success of electrical cardioversion and the duration of anti-coagulation thereafter. The aim of this study was to investigate the current management and outcomes of electrical cardioversion in unselected patients in ordinary clinical practice.

METHODS

A prospective, observational study of 111 consecutive patients with AF who had been referred for electrical cardioversion was undertaken in a large teaching hospital. After cardioversion, patients were followed-up for 12 months or until death if this occurred earlier.

RESULTS

Sinus rhythm was restored immediately in 96 of 111 (86%) patients. Only 54 of 88 (61%) patients in sinus rhythm at discharge remained in this rhythm at 1 month. Of these 54, a further 21 (39%) had relapsed into AF by 12 months. Independent predictors of sinus rhythm at discharge were younger age (for a difference of 5 years, odds ratio=1.54; 95% confidence interval 1.04 to 1.16; P=0.002) and absence of hypertension (1.73, 1.22-1.91; P=0.015). The presence of sinus rhythm at discharge (6.4, 1.6-25.3; P=0.007) was an independent predictor of sinus rhythm at 1 month, whereas older age was a negative predictor (0.96, 0.92-1.0; P=0.05). Health-related quality of life improved at 1 and 12 months in those patients who remained in sinus rhythm compared to those who remained in AF.

CONCLUSIONS

Though electrical cardioversion for AF has a high initial success rate only a minority of patients remained in sinus rhythm 1 year. The common practice of discontinuing anticoagulant treatment in patients in sinus rhythm at 1 month may be unsafe. Long-term maintenance of sinus rhythm is, however, associated with better health-related quality of life.

Efficacy of amiodarone for the termination of chronic atrial fibrillation and maintenance of normal sinus rhythm: a prospective, multicenter, randomized, controlled, double blind trial

OBJECTIVE

We sought to assess the efficacy and safety of amiodarone for restoration and maintenance of sinus rhythm in patients with chronic atrial fibrillation in a prospective, randomized, double blind trial.

BACKGROUND

Restoration and preservation of sinus rhythm is difficult in patients with chronic atrial fibrillation. The efficacy of oral amiodarone has not been conclusively established.

METHODS

Ninety-five patients with chronic atrial fibrillation, lasting an average of 35.6 months, were randomized to either amiodarone (600 mg/d) (47 patients) or placebo (48 patients) during four weeks. Nonresponders underwent electric cardioversion, and those who reverted continued with amiodarone (200 mg/d) or placebo. End-points were successful cardioversion and sinus rhythm maintenance.

RESULTS

Sixteen patients (34.04%) in the amiodarone group reverted within 27.28 +/- 8.85 days in comparison with 0% in the placebo group (P < 0.000009). The conversion rate rose to 51.72% in patients with chronic atrial fibrillation lasting less than 12 months. Twenty-eight patients in the amiodarone group and 39 in the placebo group underwent electric cardioversion, which was successful in 19 patients (67.8%) of the amiodarone group and in 15 (38.46%) of the placebo group (P = 0.017). Altogether, conversion was obtained in 79.54% of the amiodarone group patients and in 38.46% of the placebo group patients (P < 0.0001). During follow-up, atrial fibrillation relapsed in 13 (37.14%) of 35 patients of the amiodarone group within 8.84 +/- 8.57 months and in 12 (80%; P = 0.009) of 15 patients of the placebo group within 2.74 +/- 3.41 months.

CONCLUSIONS

Oral amiodarone restored sinus rhythm in one third of patients with chronic atrial fibrillation, increased the success rate of electric cardioversion, decreased the number of relapses and delayed their occurrence.

Pharmacologic conversion of atrial fibrillation: a systematic review of available evidence

This report reviews the efficacy of currently available antiarrhythmic agents for conversion of atrial fibrilation (AF) to normal sinus rhythm (NSR). A systematic search of literature in the English language was done on computerized databases, such as MEDLINE, EMBASE, and Current Contents, in reference lists, by manual searching, and in contact with expert informants. Published studies involving humans that described the use of antiarrhythmic therapy for conversion of AF to NSR were considered and only studies that examined the use of agents currently available in the United States were included. Studies exclusively describing antiarrhythmic therapy for conversion of postsurgical AF were excluded. The methodology and results of each trial were assessed and attempts were made to acquire additional information from investigators when needed. Assessment of methodological quality was incorporated into a levels-of-evidence scheme. Eighty-eight trials were included, of which 34 (39%) included a placebo group (level I data). We found in recent-onset AF of less than 7 days, intravenous (i.v.) procainamide, high-dose i.v. or high-dose combination i.v. and oral amiodarone, oral quinidine, oral flecainide, oral propafenone, and high-dose oral amiodarone are more effective than placebo for converting AF to NSR. In recent-onset AF of less than 90 days, i.v. ibutilide is more effective than placebo and i.v. procainamide. In chronic AF, oral dofetilide converts AF to NSR within 72 hours, and oral propafenone and amiodarone are effective after 30 days of therapy. We conclude than for conversion of recent-onset AF of less than 7 days, procainamide may be considered a preferred i.v. agent and propafenone a preferred oral agent. For conversion of recent-onset AF of longer duration (less than 90 days), i.v. ibutilide may be considered a preferred agent. For patients with chronic AF and left ventricular dysfunction, direct current cardioversion is the preferred conversion method. Larger, well-designed randomized controlled trials with clinically important endpoints in specific populations of AF patients are needed.

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.

Potential clinical efficacy and cost benefit of a transesophageal echocardiography-guided low-molecular-weight heparin (enoxaparin) approach to antithrombotic therapy in patients undergoing immediate cardioversion from atrial fibrillation

An alternative clinical management strategy and cost analysis model is presented for patients with atrial fibrillation of >2 days' duration who may benefit from immediate cardioversion with self-administered low-molecular-weight heparin (enoxaparin) as a bridge antithrombotic therapy to warfarin, after a negative transesophageal echo-cardiography (TEE) screening for thrombus. Assuming no difference in stroke or bleeding rates, our cost minimization model shows that the TEE-guided enoxaparin treatment costs are $1353 lower per patient than an intravenous unfractionated heparin approach. Sensitivity analyses for stroke and bleeding reveal that the treatment-cost economic dominance of the TEE-guided enoxaparin approach may be enhanced by an expected improvement in clinical outcome.

Atrial fibrillation impairs endothelial function of forearm vessels in humans

BACKGROUND

Although there have been many studies on the effects of atrial fibrillation (AF) on cardiac function, few studies have been done on its effects on endothelial function. The present study was designed to examine the effects of AF on endothelial function in human subjects.

METHODS AND RESULTS

Changes in forearm blood flow (FBF) induced by acetylcholine and nitroglycerin were measured by using plethysmography in 14 patients with lone AF, 13 patients with AF and underlying heart disease, and 12 normal control subjects. In the patients, these measurements were repeated after cardioversion. Although baseline FBF was the same in the 3 groups, acetylcholine-induced increases in FBF were significantly smaller in both patient groups than in the control group, and FBF increases were particularly depressed in AF patients with underlying heart disease. After restoration of sinus rhythm by cardioversion, FBF response to the highest dose of acetylcholine increased by 46% in patients with lone AF (n = 10) and by 90% in AF patients with underlying heart disease (n = 11). Nitroglycerin-induced vasodilatation was the same in all 3 groups and was not affected by cardioversion.

CONCLUSIONS

These findings suggest that endothelium-dependent vasodilatation is impaired by AF and improves after sinus rhythm is restored.

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.