What are the causes and treatment options for atrial fibrillation (AFib) in adults with a history of cardiovascular disease, hypertension, or diabetes?

Causes of Atrial Fibrillation

Atrial fibrillation is predominantly caused by underlying cardiovascular disease in 70-80% of cases, with hypertension being the single most common culprit, followed by coronary artery disease, heart failure, and valvular heart disease. 1

Primary Cardiovascular Causes

Hypertension and Structural Heart Disease

• Hypertensive heart disease is the leading cause of AFib, particularly when left ventricular hypertrophy develops, creating an arrhythmogenic substrate through elevated atrial pressure and diastolic dysfunction 2, 1, 3
• Hypertension was present in 39-45% of AFib patients across major studies, making it the most prevalent associated condition 2
• Left ventricular hypertrophy independently predicts AFib development in both sexes 4, 5

Coronary Artery Disease

• Coronary disease promotes AFib through atrial ischemia, structural remodeling, and increased left atrial pressure 1
• When AFib develops during acute myocardial infarction, it signals particularly poor prognosis and mandates urgent evaluation 1, 6
• AFib is more common in older patients with coronary disease, males, and those with left ventricular dysfunction 3, 4

Heart Failure

• Heart failure with either systolic or diastolic dysfunction causes atrial pressure elevation and creates electrical remodeling that strongly predisposes to AFib 1, 3
• Congestive heart failure was present in 30-43% of AFib patients in the ALFA study 2

Valvular Heart Disease

• Valvular disease, especially mitral valve involvement (rheumatic or non-rheumatic), significantly increases AFib risk regardless of severity but correlates strongly with left atrial enlargement 2, 1, 3
• Mitral stenosis and mitral regurgitation are particularly associated with AFib, though the occurrence is unrelated to the severity of the valvular lesion itself 4

Cardiomyopathies

• Hypertrophic cardiomyopathy, dilated cardiomyopathy, and other cardiomyopathies create structural substrates for AFib development 2, 3

Metabolic and Endocrine Causes

Hyperthyroidism

• Hyperthyroidism is a critical reversible cause that must be evaluated in every AFib patient, as treatment of the thyroid disorder often eliminates the arrhythmia 2, 1, 3
• Hyperthyroidism was present in 3-4.5% of AFib patients in major studies 2

Diabetes Mellitus

• Diabetes is an important predictive factor for AFib, particularly in women, and was present in 9-13% of AFib patients 2, 4, 5

Lifestyle and Behavioral Factors

Alcohol

• Alcohol consumption, both acute intoxication ("holiday heart") and chronic excessive use, is a well-recognized precipitant of AFib 1, 3

Obesity

• Obesity promotes AFib through progressive left atrial dilation that correlates directly with increasing body mass index 1

Sleep Apnea

• Sleep apnea syndrome is commonly associated with AFib, though the exact mechanism remains incompletely understood 1

Autonomic Influences

Vagal and Adrenergic AFib

• Vagally-mediated AFib typically occurs at night, during rest, or after meals, and may respond to anticholinergic agents 2
• Adrenergically-induced AFib occurs with exercise or emotional stress, with onset typically at a specific heart rate threshold; beta-blockers are the treatment of choice 2, 3

Age-Related Factors

• Advanced age is one of the strongest risk factors, with prevalence increasing from approximately 1% in those under 60 years to more than 8% in those over 80 years 3
• Age-related changes including myocardial stiffness, fibrosis, and atrial dilation contribute to AFib susceptibility 3

Lone/Idiopathic AFib

• 30-45% of paroxysmal AFib and 20-25% of persistent AFib occur without demonstrable underlying disease, particularly in younger patients 1
• Familial AFib is more common than previously recognized, with increased likelihood among offspring of affected parents, suggesting genetic susceptibility 1, 3

Other Precipitants

• Acute myocardial infarction, pericarditis, myocarditis, and pulmonary embolism can trigger AFib 1, 3
• Certain medications (both cardiovascular and non-cardiovascular) can induce AFib 3
• Sleep deprivation, emotional stress, physical exertion, and caffeine consumption may trigger episodes 3

Critical Clinical Approach

The American College of Cardiology emphasizes that clinicians must search for predisposing conditions in every patient presenting with AFib, as successful treatment of underlying causes often eliminates the arrhythmia. 1 This includes:

• Evaluating for hypertension and left ventricular hypertrophy 1, 3
• Assessing for coronary disease, particularly in older patients or those with risk factors 1, 6
• Screening for hyperthyroidism in all patients 1, 3
• Identifying heart failure and valvular disease through clinical examination and echocardiography 1, 3
• Considering sleep apnea, alcohol use, and obesity as modifiable risk factors 1, 3