History and exam

Key diagnostic factors

common

irregular pulse rate

Although a hallmark of AF, irregularity of the pulse rate may not be appreciated if the rate is very rapid. In patients with high-grade conduction block, or with regular paced complexes in patients with cardiac pacemaker devices, the pulse rate may be regular even in the presence of AF.

Other diagnostic factors

common

palpitations

Palpitations are often described as a fluttering in the chest or a feeling of the heart "racing" or "galloping".

hypotension

AF with a rapid ventricular rate may cause hemodynamic instability.

elevated jugular venous pressure

New-onset AF may be associated with heart failure.

added heart sounds

Underlying valvular disease, such as mitral stenosis due to rheumatic heart disease, may be audible.

A gallop rhythm may be heard in heart failure. The fourth heart sound is typically not heard because of an absence of atrial kick.

Pericardial rub may be heard in cases of pericarditis.

uncommon

dizziness

Occurs as a result of rapid heart rate and hypotension.

dyspnea

A history of shortness of breath and orthopnea suggests underlying heart failure, while new-onset AF with a rapid ventricular rate can also present with shortness of breath.

rales

May be present in patients with heart failure.

evidence of stroke

Signs of an acute stroke, such as hemiplegia or dysphasia, may be the first presentation of AF.

Ischemic stroke was associated with an increased risk of incident AF in a longitudinal study, especially in people with higher CHADS2 or CHA₂DS₂-VASc scores.[87]

Risk factors

strong

increasing age

Age is significantly associated with risk of AF in both sexes (odds ratio 2.1 for men and 2.2 for women for each decade of advancing age).[19][20] The prevalence of AF is 0.5% in people ages 50-59 years, and 8.8% in people ages 80-89 years.[20]

hypertension

Hypertension is one of the risk factors most strongly associated with AF globally, regardless of gender. Hypertension is significantly associated with risk of AF in both sexes (odds ratio 1.5 for men and 1.4 for women).[20][21]

orthostatic hypotension

Orthostatic hypotension is common in older age and is associated with high risk of developing new-onset AF (odds ratio up to 1.5).[33] This association is independent of the presence of hypertension and other cardiovascular risk factors.[33]

diabetes mellitus

Both prediabetes and established diabetes are associated with a significantly increased risk of AF (20% and 28%, respectively), even with adequate glycemic control.[20][34][35]

heart failure

Significantly associated with risk of AF in both sexes (odds ratio 4.5 for men and 5.9 for women).[20] AF is present in about 35% of patients presenting with acute heart failure; patients with heart failure and AF are at greater risk of all-cause mortality.[15] New-onset AF in heart failure, or vice versa, is associated with a significantly worse prognosis than with chronic concomitant AF and heart failure.[15][36]​​ AF is associated with heart failure of all stages and types including heart failure with preserved ejection fraction (HFpEF). In patients with unexplained dyspnea and normal EF, the probability of underlying HFpEF can be estimated by the H2FPEF score system (Heavy 2, Hypertension 1, AF 3, Pulmonary hypertension 1, Elder 1, and Filling pressure 1), which gives maximum score of 3 points for the presence and any history of AF.[37]​ AF is highly prevalent in HFpEF and is associated with more advanced disease, poorer exercise capacity, and increased mortality.[38]

valvular and structural heart disease

Significantly associated with risk of AF in both sexes (odds ratio 1.8 for men and 3.4 for women): in particular, mitral valve disease, and rheumatic heart disease in developing countries.[20][21] Cardiomyopathy is also strongly associated with AF; as many as 20% of patients with a cardiomyopathy of any cause (except peripartum cardiomyopathy) have AF.[21][39]

coronary artery disease and acute coronary syndromes

Coronary artery disease (CAD) and acute coronary syndromes (ACS) are significantly associated with risk of AF (odds ratio 1.4 for men and 1.2 for women).[20] Associated risk factors for the development of AF in patients presenting with ACS include older age and higher heart rate at presentation.[16] New-onset AF in patients with ACS is strongly associated with ischemic stroke.[40]

other atrial arrhythmias

May be associated with atrial flutter, Wolff-Parkinson-White syndrome, or atrioventricular nodal reentrant tachycardias.[2] Premature atrial complexes (PACs) are associated with up to three times increased risk of AF.[41]

sepsis and critical illness

AF is a common finding in patients with sepsis, particularly in patients hospitalized in intensive care units, with an incidence of up to 46% in patients with septic shock.[42][43]​​ In this patient group, AF is associated with increased length of intensive care stay, a >2-fold increased risk of in-hospital ischemic stroke, as well as increased mortality.​[19][42][43]​​[44][45]​​​​ A further increase in risk of new-onset AF is seen in patients with sepsis requiring vasopressor treatment, with fungal infection, who undergo right heart catheterization, and who are treated with corticosteroids.[45] Inflammatory processes are a common denominator of many conditions and comorbidities associated with AF, but may also play a direct role in the genesis of AF, as suggested by the finding of increased C-reactive protein before the onset of AF.[3][19]

cardiac or thoracic surgery

AF is a common postoperative complication.[2][43]​​[46]​​​ Coexisting risk factors such as obesity and vitamin D deficiency may further increase the risk of AF following cardiac surgery.[47][48]

obesity

Obesity is strongly associated with the development and recurrence of AF; weight gain is a risk factor for AF, with estimates suggesting that with every 5-unit increase in body mass index, the risk of AF increases by about 29%.[47][49][50][51] Obese people may have increased left ventricular diastolic dysfunction, sympathetic activity and inflammation, and atrial fatty infiltration, which can cause voltage abnormalities and conduction block and an increased risk of AF.[2][47] Epicardial fatty infiltration has been hypothesized as a pro-arrhythmic substrate; this may account for the significant risk of AF in obesity.[47]

hyperthyroidism

About 10% to 15% of patients with untreated thyrotoxicosis develop AF.[52]

weak

hypoxic pulmonary conditions

Includes COPD and obstructive sleep apnea.[2][22] Of patients with AF, 13% have coexisting chronic obstructive pulmonary disease (COPD); outcomes are often worse in these patients, with twice the risk of death from all causes, and increased risk of cardiovascular death and major bleeding than in patients without respiratory disease.[53] One systematic review of intensive care unit patients with new-onset AF recognized acute respiratory failure as a significant risk factor for AF.[19]

alcohol consumption

AF is a risk factor for cardiovascular disease in general, but even modest alcohol intake, of 1-2 drinks per day, is strongly associated with increased risk of AF in comparison with other cardiovascular diseases.[24][25] Alcohol consumption is associated with an increased risk of ischemic stroke in patients with newly diagnosed AF.[54] Heavy alcohol intake increases the risk of AF further, with a hazard ratio of 1.45 in men who consume ≥35 alcoholic drinks per week.[23]​​

smoking

May be associated with AF. One meta-analysis of prospective cohort studies found that the risk was higher in male smokers compared with female smokers.[55] The risk is highest in current smokers, who have a 32% increased risk of AF compared with lifelong nonsmokers.[56]

inflammatory disorders

Inflammatory disorders such as rheumatoid arthritis and psoriasis have been associated with an increased risk of AF.[57][58]

excessive exercise

Extreme levels of exercise may be associated with a higher risk of AF, or merely no further benefit.[59][60][61]

Moderate exercise, at a volume of 5-20 metabolic equivalents (METs) per week, and a high level of cardiorespiratory fitness appears to be beneficial and is associated with a decreased risk of AF.[59][61][62][63]

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.[64] 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.[65]

cancer and chemotherapy

AF has been shown to be associated with various forms of cancer including breast, colorectal, lung, kidney, and ovarian, and may even precede a diagnosis of cancer.[66] One population-based case-control study from Denmark consisting of 28,833 patients with AF and 283,260 sex-, age-, and county-matched population controls showed that patients with AF were more likely to be diagnosed with colorectal cancer within 90 days before their AF diagnosis (OR 11.8, 95% CI 9.3 to 14.9).[67]

Of the various arrhythmias induced by the various forms of cancer therapy, AF is one of the most common that is encountered, especially with tyrosine kinase inhibitors.[68][69]

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