What is the most common type of arrhythmia, characterized by an irregular and fast heartbeat?

• A. Tachycardia
• B. Bradycardia
• C. Arrhythmia
• D. Atrial fibrillation

Answer: (D)

Think about rhythm quality: an irregular and fast heartbeat points to atrial fibrillation, the most common sustained arrhythmia. In AFib the atria fire in a disorganized way, so there are no steady P waves on ECG and the ventricular response is irregular and can be rapid. That irregularly irregular rhythm distinguishes AFib from other patterns: tachycardia is fast but usually regular, bradycardia is slow, and the term arrhythmia by itself is too generic. Recognizing AFib helps explain why pulse and ECG readings can be inconsistent and why clinicians assess stroke risk and discuss treatment considerations with patients who have risk factors.