Presentation and management of patients admitted with atrial fibrillation: a review of 291 cases in a regional hospital

Sex Differences in High-Cost Users of Healthcare for Atrial Fibrillation

Background

Healthcare resource use for atrial fibrillation (AF) is high, but it may not be equivalent across all patients. We examined whether sex differences exist for AF high-cost users (HCUs), who account for the top 10% of total acute care costs.

Methods

All patients aged ≥ 20 years who presented to the emergency department (ED) or were hospitalized with AF were identified in Alberta, Canada, between 2011 and 2015. The cohort was categorized by sex into HCUs and non-HCUs. Healthcare utilization was defined as ED, hospital, and physician visits, and costs included those for hospitalization, ambulatory care, physician billing, and drugs. All costs were inflated to 2022 Canadian dollars (CAD$).

Results

Among 48,030 AF patients, 45.1% were female. Of these, 31.8% were HCUs, and the proportions of female and male patients were equal (31.9% vs 31.7%). Female HCUs were older, more likely to have hypertension and heart failure, and had a higher stroke risk than male HCUs. Mean healthcare utilization did not differ among HCUs by sex, except for number of ED visits, which was higher in male patients (12.7% vs 9.2%, P < 0.0001). Overall, HCUs accounted for 65.8% of the total costs (CAD$3.4 billion). Almost half of total HCU costs were attributable to female HCUs (CAD$966.1 million). Significant differences were present in the distributions of HCU-related costs (male patients: 74.6% hospitalization, 9.5% ambulatory care, 12.4% physician billing, 3.5% drugs; female patients: 77.7% hospitalization, 7.4% ambulatory care, 11.5% physician billing, 3.5% drugs, P < 0.0001).

Conclusions

Despite having a lower AF prevalence, female patients represent an equal proportion of HCUs, and account for almost half the total HCU costs. Interventions targeted at reducing the number of AF HCU are needed, particularly for female patients.

Is delayed cardioversion the better approach in recent-onset atrial fibrillation? Yes

Atrial fibrillation is the most common sustained arrhythmia encountered in primary care practice and represents a significant burden on the health care system with a higher than expected hospitalization rate from the emergency department. The first goal of therapy is to assess the patient's symptoms and hemodynamic status. There are multiple acute management strategies for atrial fibrillation including heart rate control, immediate direct-current cardioversion, or pharmacologic cardioversion. Given the variety of approaches to acute atrial fibrillation, it is often difficult to consistently provide cost-effectiveness care. The likelihood of spontaneous conversion of acute atrial fibrillation to sinus rhythm is reported to be really high. Although active cardioversion of recent-onset atrial fibrillation is generally considered to be safe, the question arises of whether the strategy of immediate treatment for a condition that is likely to resolve spontaneously is acceptable for hemodynamically stable patients. Based on published data, non-managed acute treatment of atrial fibrillation appears to be cost-saving. The observation of a patient with recent-onset atrial fibrillation in a dedicated unit within the emergency department reduces the need for acute cardioversion in almost two-thirds of the patients, and reduces the median length of stay, without negatively affecting long-term outcome, thus reducing the related health care costs. However, to let these results broadly applicable, defined treatment algorithms and access to prompt follow-up are needed, which may not be practical in all settings.

Coronary CT angiography in patients with atrial fibrillation: Standard-dose and low-dose imaging with a high-resolution whole-heart CT scanner

OBJECTIVE

To compare image quality, observer confidence, radiation exposure in the standard-dose (SD-CCTA) and low-dose (LD-CCTA) protocols of coronary CT angiography (CCTA) in patients with atrial fibrillation (AF).

MATERIAL AND METHODS

CCTA was performed in 303 patients using a CT scanner with 16-cm coverage (111 scans during sinus rhythm (SR); 192 during AF). LD-CCTA was used in 218 patients; SD-CCTA in 85 patients suspected of having coronary artery disease (CAD). Image quality and observer confidence were evaluated on 5-point scales. Radiation doses were recorded.

RESULTS

Image quality was superior in the SD-CCTA compared to the LD-CCTA (SR 1.45±0.40; AF 1.72±0.46; vs. SR 1.83±0.48; AF 1.92±0.50; p < 0.001). Observers were more confident with SD-CCTA than with LD-CCTA (SR 1.38±0.33; AF 1.61±0.43; vs. SR 1.70±0.45; AF 1.82±0.50; p < 0.001). Radiation doses in AF were significantly higher than in the SR (LD-CCTA, 1.68±0.71 mSv; SD-CCTA, 3.72±1.95 mSv; vs. LD-CCTA, 1.3 ±0.52 mSv; SD-CCTA, 2.67±1.47 mSv; p < 0.001).

CONCLUSION

Using a low-dose protocol in AF, radiation exposure can be decreased by 50 % at the expense of 20 % impaired image quality. A low-dose CCTA protocol can be considered in young patients, whereas the standard-dose protocol is recommended for older patients and those suspected of having CAD.

KEY POINTS

• Whole-heart CT allows visualization of the coronary arteries in atrial fibrillation. • Low-dose CT decreases radiation exposure by 50%, image quality by 20%. • Standard-dose CT seems advantageous when concomitant coronary artery disease is suspected.

Cardiovascular risk profile and management of atrial fibrillation in India: Real world data from RealiseAF survey

BACKGROUND

Atrial fibrillation (AF) is the most common sustained arrhythmia with high risk for many cardiovascular (CV) complications. Adherence to recommended management guidelines is important to avoid complications. In India, there is little knowledge on how AF is managed in real world.

METHODS

This is a cross-sectional study of patients in India enrolled in RealiseAF survey between February 2010 and March 2010 with a diagnosis of AF within the last 12 months.

RESULTS

From 15 centers, 301 patients {mean age 59.9 years (14.4); 52.5% males} were recruited. AF was controlled in 50% of patients with 77 (26.7%) in sinus rhythm and 67 (23.3%) with heart rate <80beats/min. Hypertension (50.8%), valvular heart disease (40.7%), heart failure (25.9%), and diabetes (20.4%) were the most common underlying CV diseases. Increased risk for stroke (CHADS2 score≥2) was present in 36.6%. Most of the patients (85%) were symptomatic. AF was paroxysmal, persistent, and permanent in 28.7%, 22.7%, and 34.3% respectively. In 14%, AF was diagnosed as first episode. Forty-six percent of patients had rate control, 35.2% rhythm control, 0.3% both strategies, and 18.4% received no therapy for AF before the visit. At the end of the visit, adoption to rate control strategy increased to 52.3% and patients with no therapy decreased to 7%.

CONCLUSION

AF in India is not adequately controlled. Concomitant CV risk factors and risk of stroke are high. The study underscores the need for improved adoption of guideline-directed management for optimal control of AF and reducing the risk of stroke.

Intravenous amiodarone for acute pharmacological conversion of atrial fibrillation in the emergency department

Atrial fibrillation (AF) is the most common arrhythmia seen in patients presenting to the emergency department (ED). Pharmacological conversion of atrial fibrillation to normal sinus rhythm (NSR) may be a feasible management strategy in selected patients. Recent guidelines have recommended intravenous amiodarone, a class III antiarrhythmic agent, for the conversion of AF to NSR. The purpose of this review is to examine the published evidence for the efficacy of IV amiodarone for the acute conversion of AF to NSR in the ED. Currently available data from 11 randomized, controlled trials and 3 meta analyses do not support the use of conventional doses of IV amiodarone for acute conversion in the ED. High dose IV or combined IV and oral administration may be effective as early as 8 hours in patients with recent-onset AF of <48 hour duration in patients without contraindications to these high dose regimens. There are no data to support the use of IV amiodarone for acute conversion in patients with an ejection fraction of <40% or clinical heart failure, so its use in these scenarios should be limited to symptomatic patients who are refractory to electrical conversion. More well-designed studies are required to determine the role of IV amiodarone for the acute conversion of AF in the ED.

Atrial fibrillation and ethnicity: the known, the unknown and the paradox

Current understanding of the pathophysiology and epidemiology of atrial fibrillation (AF) is based primarily on studies in White populations of European ancestry with limited data on the non-White populations. Many traditional and novel risk factors for AF have been already established. However, little is known about the differential impact of these AF risk factors in non-White versus White populations. Few studies have compared the prevalence and incidence of AF in Black versus White individuals, and still fewer extended this comparison to other races and ethnicities. These few studies consistently reported that Black individuals have lower AF burden compared with their White counterparts. These findings are not consistent with the reported high stroke rates in Black populations and the strong association between stroke and AF. In this perspective we argue that differential AF underascertainment among different racial and ethnic groups may be the key in explaining this paradox of racial/ethnic distribution of AF. Results from recent publications suggest that Black individuals would have higher rates of AF if more sensitive AF detection methods are used. Although these findings do not reach the level of definitive evidence, they may support the need for rethinking the epidemiology of AF across races and ethnicities in the context of the limited methodology available to detect AF, as well as the questionable assumption that the ability to diagnose AF across different racial/ethnic groups is the same.

Tratamiento de la fibrilación auricular en los distintos niveles asistenciales de un área sanitaria

BACKGROUND AND OBJECTIVE

Atrial fibrillation is managed in multiple settings by different specialists. We sought to analyze treatment and compliance of the prevailing guidelines of patients with atrial fibrillation attended at different levels of health care and to quantify interventions to correct treatment inadequacies.

PATIENTS AND METHOD

We included all adult patients with atrial fibrillation who presented during a 14 day-period to different levels of health care of a tertiary hospital and a related primary care clinic (family physician, cardiologist, emergency department, hospitalization). In all of them, clinical and epidemiological data in relation to atrial fibrillation, and all data referring to treatment and compliance of guidelines, were recorded prospectively.

RESULTS

293 patients were included. Clinical and epidemiological data were similar in the different settings. A great diversity in atrial fibrillation treatment was observed. In 30 and 33% of the patients, antiarrhythmic and antithrombotic treatment, respectively, did not meet the recommendations of the prevailing guidelines. The adequacy was inferior in primary care. The adequacy percentages increased slightly after the medical attention (2 and 3% respectively, p non significant) with no differences in this increase between the different settings.

CONCLUSIONS

There are no epidemiological differences between patients with atrial fibrillation treated at different levels of health care. An important number of patients do not follow the recommendations of the prevailing guidelines. There is a clear medical abstention in incorrectly treated cases.

Pulmonary hypertension and predominant right heart failure in thyrotoxicosis

In this report we discuss a patient with predominant right heart failure and pulmonary hypertension, caused by thyrotoxicosis due to Graves disease, which deteriorated to asystole, due to amiodarone administration for rapid atrial fibrillation.

Is atrial fibrillation a genetic disease?

Atrial fibrillation remains one of the most challenging arrhythmias for the clinician and basic researcher. Different approaches have been undertaken to improve its understanding; from the development of animal models to the analysis of genetic backgrounds in individuals with familial and acquired forms of the disease. In the last few years, a large body of evidence has shown that alterations in ionic currents are involved in the disease. However, it has not been until recently, with the genetic link between mutations in proteins responsible for these ionic currents and the familial disease, that we have been given the final evidence that atrial fibrillation can also be primarily an ion channelopathy. Despite the limited prevalence of the inherited diseases, it has been shown before that the knowledge gained in their study will be helpful in dealing with the most common acquired forms of the disease. Therefore, as data keep unraveling, clinicians can expect that soon better therapeutic and preventive options for atrial fibrillation will emerge from basic science.

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.

Admissions with atrial fibrillation in a multiracial population in Kuala Lumpur, Malaysia

BACKGROUND

There are established differences in cardiovascular disease in different racial groups. Worldwide, the literature regarding the clinical epidemiology of atrial fibrillation in non-white populations is scarce.

OBJECTIVES

To document the prevalence of atrial fibrillation (AF) in the multiracial population of Malaysia, and to describe the clinical features and management of these patients.

SETTING

Busy city centre general hospital in Kuala Lumpur, Malaysia, over a 1-month period.

SUBJECTS

One-thousand four hundred and thirty-five acute medical admissions, of whom 40 patients (2.8%) had AF.

RESULTS

Of 1435 acute medical admissions to Kuala Lumpur General Hospital over the 4-week study period, 40 had AF (21 male, 19 female; mean age 65 years). Of these, 18 were Malay, 16 Chinese and six Indian. Nineteen patients had previously known AF (seven with paroxysmal AF) and 21 were newly diagnosed cases. The principal associated medical conditions were ischaemic heart disease (42.5%), hypertension (40%) and heart failure (40%). Dyspnoea was the commonest presentation, whilst stroke was the cause of presentation in only two patients. Investigations were under-utilised, with chest X-ray and echocardiography in only 62.5% of patients and thyroid function checked in 15%. Only 16% of those with previously diagnosed AF were on warfarin, with a further three on aspirin. Anticoagulant therapy was started in 13.5% of patients previously not on warfarin, and aspirin in 8%. Records of contraindications to warfarin were unreliable, being identified in only 25%. For those with known AF, 58% were on digoxin. For new onset AF, digoxin was again the most common rate-limiting treatment, initiated in 38%, whilst five patients with new onset AF were commenced on amiodarone. DC cardioversion was not used in any of the patients with new onset AF.

CONCLUSION

Amongst acute medical admissions to a single centre in Malaysia the prevalence of AF was 2.8%. Consistent with previous similar surveys in mainly western (caucasian) populations, standard investigations in this Malaysian cohort were also inadequate and there was underuse of anticoagulation, medication for ventricular rate control and cardioversion to sinus rhythm.

Atrial fibrillation: guiding lessons from epidemiology

The epidemiology of AF is a challenging and surprising area of medical knowledge. The prevalence of AF may be not changing despite the common perception. It is possible that being earlier disease of the middle age, and because of changing etiology and successful treatment of underlying vascular conditions, AF is shifting to the elderly population. In this population, it becomes more clinically significant, and increasingly leads to disability and death. Screening procedures for silent AF likely are underimplemented and may change understanding of AF epidemiology significantly. Hypertension may be the most common primary etiology of AF, and the possibility of effective primary prevention of AF by strict control of hypertension needs to be evaluated adequately.

Thyroid disease

Evaluation and treatment of thyroid disease is a common feature of primary care medicine. Nevertheless, the dose of thyroid hormone used to treat hypothyroidism is frequently not titrated to normalize the TSH, engendering the risks of under- or overtreatment. Other hypothyroid patients remain symptomatic even with normalized TSH on levothyroxine alone. Some of these patients improve symptomatically when liothyronine is added to the treatment regimen. Subclinical hypothyroidism and hyperthyroidism are also relatively common in primary care medical practice, and appropriately selected patients probably benefit from treatment. In the follow-up of patients treated for thyroid cancer, the use of rhTSH improves patient comfort considerably while allowing sensitive screening for persistent or recurrent cancer.

Impact of a practice guideline for patients with atrial fibrillation on medical resource utilization and costs

Health care resource utilization is high for patients presenting with acute atrial fibrillation (AF). The potential for treatment algorithms to safely reduce resource consumption in this setting has not been prospectively evaluated. We designed and implemented a practice guideline for the management of patients presenting to the emergency department (ED) with the primary diagnosis of AF, with emphasis on appropriate cardioversion, use of oral rate-controlling medications, and expedited referral to an outpatient AF clinic. We prospectively collected clinical and resource utilization data on all such patients for 14 months before and after institution of the guideline. Institution of the guideline was associated with a decreased rate of hospital admission (from 74% to 38%), with no differences in ED return visits or hospital readmission within 30 days. No strokes or deaths were observed. This large decrease in resource utilization during the intervention phase of the study translated to an average decrease in 30-day total direct health care costs of approximately $1,400 US dollars per patient. Our clinical and cost outcomes were minimally affected after statistical adjustment for baseline differences between study groups. We conclude that the implementation of our practice guideline was feasible, safe, and effective. Widespread adoption of such practices may have large financial implications for the health care system.

Incidence, Timing, Symptoms, and Risk Factors for Atrial Fibrillation After Cardiac Surgery

• Background Atrial fibrillation is the most common complication after cardiac surgery and a major cause of morbidity and increased cost of care.

• Objectives To examine the incidence, timing, symptoms, and risk factors for atrial fibrillation after cardiac surgery.

• Methods A total of 302 patients were continuously monitored for atrial fibrillation with standard hardwire and telemetry devices during hospitalization after coronary artery bypass graft and/or valve surgery and with wearable cardiac event recorders for 2 weeks after discharge from the hospital. After discharge, patients recorded and transmitted their rhythm by telephone daily and whenever they had symptoms suggestive of atrial fibrillation.

• Results Of the 302 patients, 127 (42%) had atrial fibrillation; 41 had it after discharge, and for 10 it was their first episode. The first episode occurred at a mean of 2.9 days after surgery (SD, 3.1; range, day of surgery to 21 days after surgery). Although palpitations was the most common symptom (17%), most episodes of atrial fibrillation (69%) were not associated with symptoms. Independent predictors of atrial fibrillation were age 65 years or greater, history of intermittent atrial fibrillation, atrial pacing, male sex, white race, and not having hyperlipidemia. Independent predictors of atrial fibrillation after discharge from the hospital were having atrial fibrillation while hospitalized, valve surgery, and pulmonary hypertension.

• Conclusions Atrial fibrillation is common after cardiac surgery and often occurs after discharge from the hospital and without accompanying symptoms. Outpatient monitoring may be warranted in patients with characteristics that place them at increased risk for atrial fibrillation.

Is warfarin really underused in patients with atrial fibrillation?

CONTEXT

There is agreement that warfarin decreases stroke risk in patients with atrial fibrillation (AF), but prior studies suggest that warfarin is markedly underused, for unclear reasons.

OBJECTIVE

To determine if warfarin is underused in the treatment of patients with atrial fibrillation.

DESIGN

Cross-sectional.

SETTING

Tertiary care VA hospital.

PATIENTS

All patients with a hospital or outpatient diagnosis of AF between 10/1/95 and 5/31/98.

DATA COLLECTION

One or more physician investigators reviewed pertinent records for each patient. When any of the 3 investigators thought warfarin might be indicated, the patient's primary care provider completed a survey regarding why warfarin was not used.

RESULTS

Of 1,289 AF patients, 844 (65%) had filled at least 1 warfarin prescription. Of the 445 remaining, 19 had died, 5 had inadequate medical records, and 54 received warfarin elsewhere, leaving 367 patients. Of these, 160 had no documented AF, 53 had only a history of AF, and 49 had only transient AF. Of the remaining 105 patients, 17 refused warfarin therapy and 72 had documented contraindications to warfarin use including bleeding risk or history, fall risk, alcohol abuse, or other compliance problems. The reasons for not using warfarin among the 16 patients remaining included provider oversight (n = 4) and various reasons suggesting provider knowledge deficits.

CONCLUSION

In contrast to prior studies that suggested that warfarin is markedly underused, we found that few patients with AF and no contraindication to anticoagulation were not receiving warfarin. We believe that differing study methodologies, including the use of physician review and provider survey, may explain our markedly different rate of warfarin underutilization, although local institutional factors cannot be excluded. The findings suggest that primary providers may be far more compliant with the standard of care for patients with atrial fibrillation than previously believed.

Trends and outcomes in the hospitalization of older Americans for cardiac conduction disorders or arrhythmias, 1991-1998

OBJECTIVE

To identify epidemiological trends and measure outcomes in elderly patients hospitalized for cardiac conduction disorders or arrhythmias.

DESIGN

Review of the standard 5% samples of the Medicare Provider Analysis and Review Files to characterize 144,512 discharges from 1991 through 1998 in which the principal diagnosis was a conduction disorder or arrhythmia, using the corresponding Enrollment Databases for denominator data.

SETTING

Short-stay hospitals in the United States.

PARTICIPANTS

Medicare beneficiaries age 65 and older in the standard 5% sample.

MEASUREMENTS

Diagnosis-specific trends and rates; discharges by year; cumulative age-, race-, and sex-specific discharge rates; mean length of stay in hospital and in intensive care; mean Medicare reimbursement to the hospital; case-fatality rate in hospital; discharge destinations of patients discharged alive.

RESULTS

Annual hospitalizations for sinoatrial node dysfunction, atrial flutter, atrial fibrillation, or ventricular fibrillation increased more rapidly than did the elderly Medicare beneficiary population. Hospitalizations with a principal diagnosis of ventricular extrasystoles or asystole showed steep secular declines. Discharge rates for sinoatrial node dysfunction, a group of rhythms with a nonsinus pacemaker, atrial fibrillation, Mobitz I, or complete atrioventricular block all increased steeply and continuously with patient age. In contrast, discharge rates for atrial flutter or ventricular tachycardia or fibrillation peaked among 75- to 84-year-old patients. White men were at uniquely high risk of hospitalization for atrial flutter or ventricular tachycardia or fibrillation, and, among the white majority, men had higher discharge rates than women for nine of the 11 commonest rubrics. Whites, particularly white women, had the highest discharge rates for atrial fibrillation. Blacks, especially black women, were at disproportionate risk for hospitalization for the group of nonsinus pacemaker rhythms. Diagnosis-specific mean resource costs were strongly correlated with each other and with mean Medicare reimbursement but not with case-fatality rate.

CONCLUSION

Medicare claims data demonstrated striking differences among and within diagnoses of heart blocks or arrhythmias in terms of the populations at greatest risk for hospitalization. This variation should be explored further to generate and test hypotheses about differential causation or delivery of care.

Evaluation and management of cardiac arrhythmias in the elderly

Cardiac arrhythmias are common in elderly patients. Complete evaluation with detection of underlying structural heart disease and comorbidities is necessary. Prognosis is dependent on the presence of underlying heart disease, particularly the degree of ventricular dysfunction and the presence of comorbidities. Long-term prognosis is excellent in patients without underlying heart disease or severe comorbidities. Management and specific drug therapy in elderly patients with arrhythmias need to be individualized in reference to the underlying cardiac disorder, drug side effects, and the patient's comorbidities.

[Prevalence of auricular fibrillation in people over 65 years of age in a health area]

AIMS

To find the prevalence of auricular fibrillation in over-65s.

DESIGN

Descriptive cross-sectional study through face-to-face interview and electrocardiogram.

SETTING

La Solana Health District, Talavera de la Reina (Toledo).

PARTICIPANTS

The entire population aged 65 or over (1206 people). Main measurements. Structured interview, study of patients clinical history, taking of blood pressure, and electrocardiogram with standardised measurement.

RESULTS

5.6% prevalence of auricular fibrillation. Distribution according to gender: 4.5% in men and 6.4% in women (p = 0.060; adjusted OR, 1.5). Prevalence of auricular fibrillation by age groups: from 65 to 74, 3.9%; from 75 to 84, 7.8%; over 85, 18.2% (p = 0.0001; adjusted OR, 2.14).

CONCLUSIONS

There is greater prevalence of auricular fibrillation in the over 65s than in the general population. Prevalence increases with age. Gender has no statistical significance in the 65 to 74 age group, though it has in the over-85 group, in whom auricular fibrillation is more prevalent in women.

Cost-effective strategies in the acute management of atrial fibrillation

Atrial fibrillation is the most common sustained arrhythmia likely to be encountered in clinical practice. It is associated with significant morbidity and mortality. The treatment of patients with atrial fibrillation can be complex and costly, especially when patients are hospitalized for acute management of this arrhythmia. In this review, we summarize current approaches to the acute management of atrial fibrillation with an emphasis on the most cost-effective approaches. We review acute methods of heart rate control and cardioversion, including pharmacologic and other minimally invasive strategies. We believe that the most cost-effective approaches may require the use of standardized clinical pathways. This may help to ensure that patients with acute atrial fibrillation receive the most effective and efficient care.

Pharmacotherapy of atrial fibrillation

Atrial fibrillation (AF) remains a widespread health problem and the drugs available for its treatment suffer from several drawbacks, including potentially lethal proarrhythmia, serious non-cardiac toxicity and limited efficacy. The evidence for efficacy of currently available anti-arrhythmic agents for sinus rhythm restoration and maintenance is reviewed, with emphasis on randomised trials when available. The current approach to thromboembolism prophylaxis in AF is summarised.

Molecular biology and atrial fibrillation

Atrial fibrillation remains one of the most challenging arrhythmias in cardiology. Despite the overall advance in the treatment of patients with cardiac dysrhythmias with the introduction of radiofrequency ablation, therapeutic options in atrial fibrillation have remained largely unchanged and aimed at controlling the heart rate and anticoagulation. New surgical and ablation compartmentalization techniques are being developed that are promising, but to date these techniques are still extremely laborious and available only to a handful of patients. Advances in genetics and molecular biology will likely give new insights into the development of the disease. Molecular biology research is presently focused into two main fields: 1) identification of the genes that cause familial forms of the disease, and 2) altered gene expression during the disease state. These studies are aimed at identifying not only the triggering factors in the acute form but also those that prolong the arrhythmia and convert it into a chronic form.

The new onset of atrial arrhythmias following major noncardiothoracic surgery is associated with increased mortality

STUDY OBJECTIVES

To examine the incidence and consequences of atrial arrhythmias in surgical ICU patients following major noncardiac, nonthoracic surgery.

DESIGN

Prospective observational study.

SETTING

University hospital surgical ICU.

PATIENTS

Four hundred sixty-two consecutive patients after noncardiothoracic surgery.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Patients were assigned to one of three groups: group 1-new-onset atrial arrhythmias (n=47); group 2-history of atrial arrhythmias (n=58); and group 3-no atrial arrhythmias (n=357). New arrhythmias occurred in 10.2% of patients. Most began within the first 2 postoperative days. These patients had a higher mortality rate (23.4%), longer ICU stay (8.5+/-17.4 [SD] days), and extended hospital stay (23.3+/-23.6 days) than patients without atrial arrhythmias (mortality, 4.3%; ICU stay, 2.0+/-4.5 days; hospital stay; 13.3+/-17.7 days; p<0.02). Thirteen percent of patients had a history of atrial arrhythmias. They had a higher mortality rate (8.6%) and longer ICU stays (2.9+/-4.9 days; p<0.02) than patients without arrhythmias. Most deaths in the two arrhythmia groups were not due to cardiac problems, but to sepsis or cancer.

CONCLUSIONS

Patients admitted to a surgical ICU after noncardiothoracic surgery with a history of or who developed new atrial arrhythmias had greater mortality and longer ICU stays than patients without arrhythmias. The incidence of new-onset arrhythmias was lower than reported after cardiac and thoracic surgery, but higher than in the general population. Atrial arrhythmias were not the cause of death and appear to be markers of increased mortality and morbidity.

Atrial fibrillation amongst the Indo-Asian general practice population. The West Birmingham Atrial Fibrillation Project

Whilst there are recognised ethnic differences in cardiovascular disease, with a higher prevalence of hypertension and complications such as stroke amongst black/Afro-Caribbean populations, and ischaemic heart disease being more prevalent amongst Indo-Asians, the literature describing the clinical epidemiology of atrial fibrillation (AF) in non-caucasian groups is scarce. To survey the clinical features and management amongst Indo-Asian patients with known AF, we studied patients from six general practices in the west of Birmingham. The six general practices had a combined practice population of 25051, from which, the Indo-Asian population was 14670. A total of 12 Indo-Asian patients (six male, six female; mean age, 67 years; range, 42 to 95 years) with known AF were identified, suggesting a prevalence of AF in Indo-Asians aged >50 years of 0.6%. Six patients had chronic AF, two had recent onset (defined as onset <six months) and four had paroxysmal AF. Five patients had a history of ischaemic heart disease, three had hypertension, seven had heart failure, two had alcohol excess, four had mitral valve disease, and one patient with paroxysmal AF had sick sinus syndrome. None could be classified as having lone AF. Only four patients were anticoagulated, but, of the remaining eight, who were not taking warfarin, six were taking aspirin. None of the patients had contraindications to warfarin, but one of the patients who was taking aspirin had poor compliance to warfarin. In this survey of a general practice Indo-Asian population of approximately 14670, we found 12 patients with known AF. More information on the clinical epidemiology of AF in non-caucasian groups is still needed and urgently required, in view of the public health implications of this common cardiac arrhythmia.

Abnormal vasovagal reaction, autonomic function, and heart rate variability in patients with paroxysmal atrial fibrillation

The aim of this study was to evaluate the cardiovascular autonomic function and vasovagal reaction in patients with paroxysmal atrial fibrillation without significant structural heart disease. Twenty-eight patients with paroxysmal atrial fibrillation (9 patients were categorized to have autonomic-mediated atrial fibrillation while atrial fibrillation in other patients was nonautonomic mediated) and 19 normal control subjects were recruited. Cardiovascular autonomic function tests included measuring heart rate response to standing, deep breathing, Valsalva maneuver, baroreflex sensitivity, 24-hour heart rate variability, and also head-up tilt test. Compared with normal subjects, no significant autonomic dysfunction was found in patients with autonomic-mediated and nonautonomic-mediated atrial fibrillation. All subjects had negative baseline tilt test. With isoproterenol provocation, six patients developed atrial fibrillation. Four of 9 patients and 3 of 19 patients with autonomic mediated and nonautonomic mediated atrial fibrillation had a positive tilt test respectively, while none occurred in the controls. A significant percentage (32%) of patients with paroxysmal atrial fibrillation had episodes of atrial fibrillation provoked by changes in autonomic tone, although there was no underlying abnormal cardiac autonomic function nor sympathetic-parasympathetic imbalance. A heightened susceptibility to vasovagal cardiovascular response may have important implications on the occurrence and symptomatology of patients with paroxysmal atrial fibrillation.

Electrical remodelling of chronic atrial fibrillation

1. It is now recognized that atrial fibrillation (AF) is not a benign condition, as it is associated with a 40% increase in mortality and a doubling of the risk of stroke. 2. The development of AF leads to mechanical, electrophysiological and cellular changes in the atria that tend to sustain AF. This process is known as atrial remodelling. 3. The three electrophysiological elements in the atria that initiate and sustain AF are: (i) shortening of the refractory period and an increase in dispersion; (ii) slowing of conduction velocity; and (iii) the presence of triggering foci. 4. As AF is a heterogeneous disorder, therapeutic strategies include the use of devices (pacemakers and atrial defibrillators), radiofrequency ablation (focal ablation or the creation of linear lines) and drug therapy that may reverse a remodelled atrium.

Atrial fibrillation: a review of mechanism, etiology, and therapy

The prevalence of elderly individuals in the populations of developed countries is increasing rapidly, and atrial fibrillation (AF) is quite common in these elderly patients: currently, 11% of the U.S. population is between the ages of 65 and 85 years; 70% of people with AF are between the ages of 65 and 85 years. AF causes symptoms secondary to hemodynamic derangements that are the result of increased ventricular response and loss of atrial booster function. AF can lead to reversible impairment of left ventricular function, cardiac chamber dilatation, clinical heart failure, and thromboembolic events. AF requires treatment in order to prevent these potential complications. Type Ia, Ic, and III antiarrhythmics are capable of converting AF to normal sinus rhythm (NSR). Amiodarone has the greatest efficacy and safety for converting AF and maintaining NSR while digoxin and verapamil are ineffective in restoring NSR. Quinidine, flecainide, disopyramide, and sotalol have also been shown to maintain NSR after conversion of AF. Proarrhythmia is a definite concern with the latter four agents. Alternative therapy for AF includes anticoagulation with warfarin or aspirin for the prevention of thromboembolic events, and a variety of agents to control the ventricular response. All medications used to treat AF carry significant risks in the elderly, whether from proarrhythmia, overdosing because of compliance errors, or hemorrhage secondary to anticoagulation. Treatment of AF must be based on a careful risk-benefit evaluation. The physician must know the capability of the particular patient as well as drug mechanisms and effects in the elderly. The decision to convert patients from AF to NSR or to leave the patient in AF and control the ventricular response represents a complex intellectual challenge. Factors favoring one or the other of these two clinical strategies are discussed. Multicenter clinical trials, for example, the Atrial Fibrillation Follow-up Investigation Rhythm Management (AFFIRM) trial, are currently underway to assess various clinical strategies for maintenance of NSR following conversion from AF. Amiodarone is one of the drugs under investigation.

Oxygen uptake kinetics and cardiopulmonary performance in lone atrial fibrillation and the effects of sotalol

BACKGROUND

Atrial fibrillation (AF) is associated with impaired exercise capacity. Oxygen uptake (VO2) kinetics determines cardiopulmonary performance during submaximal exercise, which may be impaired in patients with AF.

AIM

To study oxygen kinetics and cardiopulmonary performance in patients with AF without structural heart disease and the effects of oral sotalol on these parameters.

PATIENTS AND METHODS

Twenty consecutive patients (mean age, 56+/-8 years) with chronic AF were recruited. The protocol design was a randomized, single-blinded, and placebo-controlled trial. Patients received either sotalol or placebo for an 8-week study period, and the alternative treatment in the subsequent period. Cardiopulmonary function tests using constant workload and incremental workload protocols were performed at the end of each phase. Sixteen age-matched normal subjects were included as control subjects.

RESULTS

During constant submaximal exercise, patients with AF had a larger oxygen deficit (425+/-140 mL vs 289+/-80 mL in normal subjects; p<0.05) and the time for achieving 63% of VO2 (mean response time) was also delayed (46+/-15 s vs 33+/-10 s; p<0.05). Compared with normal subjects, patients with chronic AF had a higher maximal exercise heart rate (180+/-34 beats/min vs 153+/-22 beats/min; p<0.05), but a lower maximal VO2 (20+/-4 mL/kg/min vs 26+/-6 mL/kg/min; p<0.05). Oral sotalol lowered the resting (72+/-15 beats/min vs 93+/-22 beats/min; p<0.05) and exercise heart rate compared with placebo (125+/-27 beats/min vs 180+/-34 beats/min; p<0.05, respectively), and normalized oxygen pulse and the heart rate to minute ventilation ratio during maximal exercise. There was no significant difference between those receiving sotalol and those receiving placebo in oxygen deficit (502+/-150 mL vs 425+/-140 mL; p=0.38), maximal VO2 (17.2+/-4.9 mL/kg/min vs 20.4+/-4.7 mL/kg/min; p=0.17), and other gas exchange variables. In patients with AF, oxygen deficit has a fair correlation with VO2 at the anaerobic threshold (r2=0.43; p<0.05) and at maximal exercise (r2=0.45; p<0.05).

CONCLUSION

In addition to maximal exercise capacity and cardiopulmonary performance, patients with chronic AF without significant structural heart disease had impaired submaximal exercise performance as assessed by VO2 kinetics. These parameters were not significantly affected by sotalol used for rate control.

Prevalence of palpitations, cardiac arrhythmias and their associated risk factors in ambulant elderly

To determine the prevalence of palpitations, cardiac arrhythmias and associated cardiovascular risk factors in an ambulatory elderly population, 1454 ambulatory elderly people (219 men and 1235 women, age range 60-94 years) were assessed in a territory-wide health survey including anthropometric measurements, biochemical blood tests, questionnaire interview and resting surface ECG examination. Prevalence of palpitations and ECG abnormalities were determined and correlated with coronary risk factors and biochemical blood tests. Palpitations were present in 121 subjects (8.3%) and cardiac arrhythmias were found in 183 subjects (12.6%). Conduction abnormalities and sinus bradycardia were the commonest findings (9.8%). Premature beats (atrial 2.3%; ventricular 1%) were the next most frequent arrhythmia. Atrial fibrillation was the commonest sustained arrhythmia that was present in 19 subjects (1.3%). Compared with those without arrhythmia on ECG, people with arrhythmias were predominantly males and were older (72 +/- 8 years vs. 70 +/- 6 years, P < 0.05), had a higher prevalence of smoking (12.9% vs. 5%, P < 0.05) and coronary heart disease (30.7% vs. 11.4%, P < 0.05). The prevalence of palpitations between subjects with documented arrhythmias (excluding conduction disturbance) and those without arrhythmias on surface ECG was similar (9% vs. 7.7%, P = N.S.). We conclude that cardiac arrhythmias are common in the elderly and are often asymptomatic. Subjects with ECG documented arrhythmias are more common in males, and are associated with smoking and ischaemic heart disease. Palpitation was a frequent complaint in the ambulatory elderly with no bearing on arrhythmias recorded on resting ECG.