Causes
- Age-associated atrial fibrosis, left atrial enlargement, and alterations in diastolic filling
- Cardiac disease: heart failure (HF), cardiomyopathy, cardiac amyloidosis, cardiac surgery, hypertensive heart disease, ischemic heart disease, pericarditis, valvular disease
- Noncardiac disease: alcoholism, chronic pulmonary disease, obstructive sleep apnea, infections, pulmonary emboli, thyrotoxicosis, electrolyte abnormalities, non-cardiac surgery
Clinical Features
- Symptoms related to AF are highly variable.
- Most common:
- Palpitations
- Shortness of breath
- Impaired exercise tolerance
- Fatigue
- Some patients are entirely asymptomatic, while others present with acute coronary syndrome or pulmonary edema.
- Stroke and transient ischemic attack are increasingly being recognized as the initial manifestation in older adults.
Diagnosis
- In patients with ongoing AF, the standard 12-lead electrocardiogram is diagnostic. Additional laboratory studies should include at a minimum:
- Evaluation of serum electrolytes (especially potassium and magnesium)
- Thyroid stimulating hormone (TSH)
- Complete blood count (CBC)
- Creatinine (Cr)
- Blood urea nitrogen (BUN)
- Glucose
- A transthoracic echocardiogram is indicated in all patients with new-onset AF to evaluate LV size and function, left atrial size, pulmonary artery pressure, cardiac valves, and pericardium.
- Further evaluation in selected cases might include a chest radiograph, serial cardiac biomarker proteins to exclude acute MI, B-type natriuretic peptide (BNP) or NT-proBNP level, ᴅ-dimer level, lower extremity venous Dopplers, and an evaluation for pulmonary embolism.