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 bi-atrial enlargement is summarized 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)
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).
- Chung DC, Nelson HM. ECG – A Pictorial Primer [internet].
- 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. PMID: 12028984; PMC1123219
- Harrigan RA, Jones K. ABC of clinical electrocardiography. Conditions affecting the right side of the heart. BMJ. 2002 May 18;324(7347):1201-4. PMID: 12016190; PMC1123164
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
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric
- Wagner GS. Marriott’s Practical Electrocardiography 12e
- Chan TC. ECG in Emergency Medicine and Acute Care
- Rawshani A. Clinical ECG Interpretation
- Mattu A. ECG’s for the Emergency Physician
- Hampton JR. The ECG In Practice, 6e