Irregularly irregular rhythm
Also calledchaotic rhythm · random irregularity · irregularly irregular
Definition
A rhythm in which the R-R intervals are irregular and vary from beat to beat, so successive beats are unevenly spaced. The classic cause is atrial fibrillation (irregular R-R intervals, no distinct P waves and fibrillatory waves); other causes include multifocal atrial tachycardia (at least 3 distinct P-wave morphologies, always irregular), atrial flutter with variable AV conduction, and sinus rhythm with frequent premature beats.
Sources
- Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS guideline for the diagnosis and management of atrial fibrillation. Circulation. 2024;149(1):e1-e156. doi.org/10.1161/CIR.0000000000001193
- Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia. Circulation. 2016;133(14):e506-e574. doi.org/10.1161/CIR.0000000000000311
- Neumar RW, Otto CW, Link MS, et al. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;122(18 Suppl 3):S729-S767. doi.org/10.1161/CIRCULATIONAHA.110.970988
- Samesima N, God EG, Kruse JCL, et al. Brazilian Society of Cardiology guidelines on the analysis and issuance of electrocardiographic reports - 2022. Arq Bras Cardiol. 2022;119(4):638-680. doi.org/10.36660/abc.20220623
Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.