Biatrial Enlargement Definition
- Biatrial enlargement is diagnosed when criteria for both right and left atrial enlargement are present on the same ECG.
- The diagnosis of biatrial enlargement requires criteria for LAE and RAE to be met in either lead II, lead V1 or a combination of leads
ECG Criteria for Biatrial Enlargement
The spectrum of P-wave changes in leads II and V1 with right, left, and biatrial enlargement is summarised below:
In lead II
Bifid P wave with
- Amplitude ≥ 2.5mm AND
- Duration ≥ 120 ms
Biphasic P waves with
- Initial positive deflection ≥ 1.5mm tall AND
- Terminal negative deflection ≥ 1mm deep AND
- Terminal negative deflection ≥ 40 ms duration
- P wave positive deflection ≥ 1.5 mm in leads V1 or V2 AND
- Notched P waves with duration >120 ms in limb leads, V5 or V6
P wave changes with Biatrial Enlargement
Causes of Biatrial Enlargement
Combination of both left and right atrial enlargement.
- Pulmonary hypertension due to:
- Chronic lung disease (cor pulmonale)
- Tricuspid stenosis
- Congenital heart disease (pulmonary stenosis, Tetralogy of Fallot)
- Primary pulmonary hypertension
- Mitral valve disease
- Aortic valve disease
- Aortic stenosis
- Mitral incompetence
- Hypertrophic cardiomyopathy (HOCM)
- Lead II: Bifid P wave with Amplitude ≥ 2.5mm AND Duration ≥ 120 ms
- P wave positive deflection ≥ 1.5 mm in lead V2
- Leads V5 and V6: Notched P waves with duration >120 ms in limb leads
Biatrial enlargement due to idiopathic cardiomyopathy:
- Biphasic P waves in V1 with a very tall positive deflection (almost 3 mm in height!) and a negative deflection that is both deep (> 1 mm) and wide (> 40 ms).
- P waves in lead II are tall (> 2.5mm) and wide (> 120 ms).
- P waves in V2 are tall (> 1.5 mm), while the terminal negative portion of V1 is deep (> 1mm) and wide (> 40 ms).
- Edhouse J, Thakur RK, Khalil JM. ABC of clinical electrocardiography. Conditions affecting the left side of the heart. BMJ. 2002 May 25;324(7348):1264-7
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- Chung DC, Nelson HM. ECG – A Pictorial Primer [internet].
- Wiesbauer F, Kühn P. ECG Yellow Belt online course: Become an ECG expert. Medmastery
- Wiesbauer F, Kühn P. ECG Blue Belt online course: Learn to diagnose any rhythm problem. Medmastery
- Rawshani A. Clinical ECG Interpretation ECG Waves
- Smith SW. Dr Smith’s ECG blog.
- Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
- Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
- Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
- Hampton J. The ECG Made Practical 7e, 2019
- Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography 1e, 2009
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
- Mattu A, Brady W. ECG’s for the Emergency Physician Part I 1e, 2003 and Part II
- Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004
- Smith SW. The ECG in Acute MI. 2002 [PDF]
LITFL Further Reading
- ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis – ECG interpretation in clinical context
- ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
- 100 ECG Quiz – Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS – the best of the rest