History and exam
Key diagnostic factors
common
presence of cardiovascular risk factors
Key cardiovascular risk factors for AF include hypertension, coronary artery disease (CAD), heart failure, valvular heart disease, cardiomyopathy, and presence of other arrhythmias.
presence of noncardiovascular risk factors
Key noncardiovascular risk factors for AF include conditions such as diabetes mellitus, thyroid disease, alcohol misuse, and certain cancers (e.g., primary lung cancer involving the pleura and pericardium; breast cancer and malignant melanoma metastasizing to the pericardium). AF can also develop during cancer treatment with surgery, radiation therapy, and chemotherapy.[59]
palpitations
Common symptom, although some patients are asymptomatic.
tachycardia
Most patients have tachycardia if not already taking a rate-controlling medication.
irregular pulse
Over 90% of patients with persistent atrial fibrillation (AF) have irregular pulse on palpation. However, an apparently regular pulse does not exclude AF. It can be extremely difficult to appreciate irregularity if the pulse rate is very rapid or very slow. The latter may occur in patients with very poor atrioventricular (AV) nodal conduction due to intrinsic AV nodal disease or AV nodal blocking drugs.
An apparently irregular pulse does not always indicate AF; for example, other causes of irregular pulse are frequent premature atrial and/or ventricular complexes in the presence of sinus rhythm, atrial tachycardia, or atrial flutter. It is therefore necessary to confirm the rhythm with an ECG.
Other diagnostic factors
common
stroke
As a complication of atrial fibrillation (AF).
Studies evaluating patients with a first-ever ischemic stroke have found a high (15% to 25%) prevalence of AF.[4][5]
Studies assessing prolonged ECG monitoring (using a 30-day event-triggered recorder or an insertable cardiac monitoring device) in patients with cryptogenic stroke have found AF to be common in these patients.[92][93]
uncommon
shortness of breath
Patients may present with dyspnea due to atrial fibrillation-related cardiomyopathy.
fatigue
Patients may present with fatigue due to atrial fibrillation-related cardiomyopathy.
chest pain
Patients may present with anginal chest pain due to concomitant CAD.
dizziness
The reasons for dizziness are several. Due to loss of atrial kick and resultant decline in the stroke volume, patients with stiff ventricles and diastolic dysfunction in particular may experience dizziness.
Patients may also develop dizziness due to thromboembolic events, or due to poor cerebral perfusion, especially if they have concomitant cerebrovascular disease.
syncope
Patients may present with syncope.[91]
hypotension
Atrial fibrillation with a rapid ventricular rate may cause hemodynamic instability.
elevated jugular venous pressure
A feature of associated heart failure.
murmur or gallop rhythm
Murmurs associated with underlying valvular disease, such as mitral stenosis due to rheumatic heart disease, may be audible. A gallop rhythm may be heard in heart failure.
rales
A feature of associated heart failure.
decrease in mentation or listlessness
In an older patient the symptoms may be as subtle as a decrease in mentation or listlessness. Multiple studies have shown a clear association between atrial fibrillation and increased risk of cognitive impairment and dementia.[80] This association is independent of whether patients had prior stroke or not, and whether dementia is due to Alzheimer disease or vasculopathies.[84]
Risk factors
strong
hypertension
Hypertension is a strong established risk factor for development of atrial fibrillation (AF) and is a common comorbidity.[12][26][27][28] In the Framingham study, hypertension was significantly associated with risk of AF in men and women (odds ratios 1.5 and 1.4 respectively).[27] Increased systolic and diastolic blood pressure in what is considered within the normal range has also been associated with increased risk of developing AF.[28] Likely mechanisms may be related to the effect of pressure and myocardial stretch on the electrophysiologic characteristics in the atrial muscle.
coronary artery disease (CAD)
congestive heart failure
Heart failure and AF often coexist, and the two conditions may cause or exacerbate each other.[2] Heart failure is a powerful predictor of the occurrence of AF, being diagnosed in as many as 35% of patients, and this may be an underestimate.[31] The mechanisms are related to atrial stretch-mediated effects. AF occurs more commonly in patients with heart failure with preserved ejection fraction.[3] The presence of AF in patients with heart failure is associated with a worse prognosis.[3]
advancing age
Prevalence increases dramatically with advancing age for both sexes (odds ratio of 2.1 for men and 2.2 for women for each decade of advancing age); at least double after age 50 years.[27]
diabetes mellitus
valvular disease
Valvular heart disease is found in 33% of patients with AF.[3] Strong association with rheumatic heart disease, especially mitral stenosis and mitral regurgitation. In the Framingham study, valve disease was significantly associated with risk of AF in men and women (odds ratios 1.8 and 3.4 respectively).[27]
hypertrophic cardiomyopathy
Around 20% to 25% of patients with hypertrophic cardiomyopathy also have AF.[3]
alcohol misuse
Excessive amounts of alcohol acutely or moderate amounts over a long period, particularly if associated with a cardiomyopathy, are associated with an increased risk of AF.[33][34] The associations are variably reported but several studies suggest a relationship.[35][36][37] It can also be seen with withdrawal symptoms.[38][39]
presence of other arrhythmias
AF may also result as degeneration of other rapid arrhythmias, such as atrial tachycardia, atrial flutter, or atrioventricular nodal reentrant tachycardia and atrioventricular reentrant tachycardia.
smoking
Smoking is associated with the incidence of AF, with more than a twofold increased risk of AF attributed to current smoking.[3]
Among smokers who quit, there is a trend toward a lower incidence of AF compared with those who continue to smoke.
In the large prospective Atherosclerosis Risk in Communities study, participants were followed-up for over a mean of 13.1 years.[40] Compared with never smokers, the multivariable-adjusted hazard ratios for AF were 1.32 (95% CI 1.10 to 1.57) in former smokers, 2.05 (95% CI 1.71 to 2.47) in current smokers, and 1.58 (95% CI 1.35 to 1.85) in ever smokers. Associations were similar by sex, race, and type of AF. People who quit smoking exhibited a trend indicating a slightly lower risk of developing AF compared with those who continued to smoke.[40]
obesity
sleep-disordered breathing (SDB)
SDB, comprising obstructive sleep apnea (OSA), central sleep apnea, and Cheyne-Stokes breathing, is strongly associated with AF.[43]
The prevalence of OSA among people with AF is estimated at 50% or higher.[44] OSA and AF share common risk factors (e.g., age, male sex, obesity, hypertension, and heart failure).[43][45] There is mounting evidence for a cause-effect relationship between SDB and AF; for example, the VARIOSA-AF cohort study (Variability of Sleep Apnea Severity and Risk of Atrial Fibrillation) showed that ≥1 hour of AF was twice as likely the day after nights with the highest SDB severity compared with nights with the lowest SDB severity. Conversely, AF did not predict respiratory disturbances.[43][46] Sustained physiologic stresses associated with SDB, including disturbed sleep, autonomic fluctuations, and repetitive hypoxia and hypercapnia, are thought to interact with circadian mechanisms to remodel the structure and electrophysiologic function of the heart over time, increasing the risk of rhythm disorders.[43] Use of continuous positive airway pressure in patients with OSA is associated with a reduced risk of recurrent AF after catheter ablation.[47] However, there is a need for high-quality randomized clinical trial evidence in this area.[43] See Obstructive sleep apnea, Central sleep apnea.
chronic obstructive pulmonary disease (COPD)
COPD is present in 10% to 15% of patients with AF and is an independent predictor of AF progression from paroxysmal to permanent.[3]
chronic kidney disease (CKD)
sedentary lifestyle
Physical inactivity may be an independent risk factor for AF.[49]
thyroid disease
About 10% to 15% of patients with untreated thyrotoxicosis develop AF.[50][51][52]
Suppressed thyroid-stimulating hormone alone is a risk factor for AF. In the older population, hyperthyroidism may not be clinically evident (apathetic hyperthyroidism) and AF may be a clinical sign of this entity.[50][52]
One meta-analysis found that subclinical hyperthyroidism, subclinical hypothyroidism, and clinical hyperthyroidism were all associated with an increased risk of AF.[53]
weak
autonomic neuronal dysfunction
Increased parasympathetic tone is linked to the occurrence of AF, as it heterogeneously reduces the atrial effective refractory period and predisposes to reentry.[18][54][55][56] Investigational drugs that block certain potassium channels regulated by acetylcholine suppressed AF in certain experimental models. Data from catheter ablation procedures suggest better long-term outcomes with denervation of parasympathetic ganglia near the pulmonary veins.
caffeine misuse
Can be a risk factor in susceptible people.
cancer
Patients with cancer have an increased risk of developing AF, and the risk may depend on type of cancer.[57][58]
AF may also develop in patients undergoing cancer treatment, particularly in those ≥65 years and/or with pre-existing cardiovascular disease.[59] Cancer surgery is associated with AF, with the highest rate reported for lung surgery.[59] In addition, patients who have had radiation therapy to the mediastinum for cancers such as Hodgkin and non-Hodgkin lymphoma are prone to AF. Many chemotherapy agents are also associated with the development of AF, for example, tyrosine kinase inhibitors.[59][60]
working long hours
One prospective multi-cohort study found that people who worked long hours (≥55 hours per week) were more likely to develop AF than those working standard hours (35-40 hours per week).[61]
excessive exercise
height
Taller individuals are likely to be at increased risk of AF. Likely mechanisms are related to the larger left atrial size that is associated with tall stature.[63] In the Copenhagen City Heart Study, height was found to be a risk factor for incident AF, with 35% to 65% higher risk of AF per 10 cm difference in height.[64]
air pollution
migraine
Studies suggest that there is an association between migraine with aura and incidence of AF in otherwise healthy individuals.[67]
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