Differential Diagnosis for Atrial Fibrillation (AF) vs. Supraventricular Tachycardia (SVT)
When differentiating between AF and SVT, it's crucial to consider the clinical presentation, electrocardiogram (ECG) findings, and patient history. Here's a structured approach to the differential diagnosis:
- Single Most Likely Diagnosis
- Atrial Fibrillation (AF): This is often the most likely diagnosis in patients presenting with an irregularly irregular rhythm, especially if they have risk factors such as hypertension, heart failure, or a history of cardiac surgery. AF is characterized by rapid and irregular atrial impulses, leading to an irregular ventricular response.
- Other Likely Diagnoses
- Paroxysmal Supraventricular Tachycardia (PSVT): This condition involves sudden episodes of rapid heart rate that originate above the ventricles. It can present similarly to AF but typically has a more regular rhythm and may be precipitated by factors such as stress or caffeine.
- Atrial Flutter: Atrial flutter is characterized by a rapid but regular atrial rhythm, which can be confused with AF or SVT. It often presents with a fixed block (e.g., 2:1,3:1,4:1), leading to a regular ventricular response.
- Do Not Miss Diagnoses
- Wolff-Parkinson-White (WPW) Syndrome: This condition involves an accessory electrical pathway between the atria and ventricles, leading to pre-excitation of the ventricles. It can cause SVT and, if not recognized, can lead to life-threatening arrhythmias.
- Multifocal Atrial Tachycardia (MAT): MAT is characterized by an irregular atrial rhythm with multiple P-wave morphologies, which can be mistaken for AF. It is often seen in patients with severe pulmonary disease.
- Rare Diagnoses
- Junctional Tachycardia: This is a rare condition where the atrioventricular junction acts as an ectopic pacemaker, leading to a rapid heart rate. It can be difficult to distinguish from other forms of SVT.
- Mahaim Fiber Tachycardia: A rare form of SVT involving an accessory pathway, which can mimic other supraventricular arrhythmias.
Each of these diagnoses has distinct ECG characteristics and clinical presentations that can help guide the differentiation between AF and SVT. Accurate diagnosis is crucial for appropriate management and treatment.