Atrial Fibrillation with Rapid Ventricular Response

Diagnostic Characteristics

Atrial fibrillation is characterized by the replacement of consistent P waves with rapid oscillations or fibrillatory waves on electrocardiogram (ECG), with a ventricular response that is typically irregular, according to the American College of Cardiology and the European Society of Cardiology 1, 2
The ventricular rate in AFib with RVR is frequently rapid, often exceeding 100-120 beats per minute, which distinguishes it from controlled AFib, as stated by the American College of Cardiology 2
The atrial cycle length is usually variable and less than 200 ms, resulting in a rate of ≥300 bpm, as reported by the European Heart Journal 3

The ventricular response to AFib depends on electrophysiological properties of the AV node, level of vagal and sympathetic tone, presence or absence of accessory conduction pathways, and action of drugs affecting AV nodal conduction, according to the American College of Cardiology and the European Society of Cardiology 1, 2, 4
Extremely rapid rates (over 200 beats per minute) strongly suggest the presence of an accessory pathway or ventricular tachycardia, as indicated by the American College of Cardiology and the European Society of Cardiology 1, 2

Acute loss of coordinated atrial mechanical function reduces cardiac output by 5-15%, as reported by the European Heart Journal 4
High ventricular rates limit ventricular filling due to shortened diastolic interval, and irregularity of ventricular response can further reduce cardiac output, according to the European Heart Journal 4
Persistent elevation of ventricular rates above 120-130 bpm may produce ventricular tachycardiomyopathy, as stated by the European Heart Journal 4

AFib with RVR can lead to serious complications, including heart failure exacerbation, as reported by the American College of Cardiology 5
Tachycardia-induced cardiomyopathy with prolonged rapid rates is a potential complication, according to the European Heart Journal 4
Increased risk of stroke and thromboembolism is associated with AFib with RVR, as indicated by the American College of Cardiology 5

Other supraventricular arrhythmias may mimic AFib with RVR, including atrial flutter with variable conduction, atrial tachycardias, and rare forms of frequent atrial ectopy, as reported by the European Heart Journal and the American College of Cardiology 1, 2, 3
A 12-lead ECG of sufficient duration and quality is essential to evaluate atrial activity and confirm the diagnosis, according to the European Heart Journal 3

AFib with RVR may be misdiagnosed as atrial flutter when atrial activity is prominent on ECG, as stated by the American College of Cardiology 2
Regular RR intervals are possible in AFib in the presence of AV block or interference by ventricular or junctional tachycardia, which may confuse the diagnosis, according to the American College of Cardiology and the European Society of Cardiology 1, 6