Biatrial Enlargement

To best understand ECG features of biatrial enlargement, it is recommended that you first review ECG changes seen in left atrial enlargement and right atrial enlargement.

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

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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

In V1/V2

Biphasic P waves with

• Initial positive deflection ≥ 1.5mm tall AND
• Terminal negative deflection ≥ 1mm deep AND
• Terminal negative deflection ≥ 40 ms duration

Combination criteria

• 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

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P wave changes with Biatrial Enlargement

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Causes of Biatrial Enlargement

Combination of both left and right atrial enlargement.

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

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Left Atrial Enlargement

• Mitral valve disease
• Aortic valve disease
• Hypertension
• Aortic stenosis
• Mitral incompetence
• Hypertrophic cardiomyopathy (HOCM)

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ECG Examples

Example 1

Biatrial enlargement:

• 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

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Example 2

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).

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Example 3

Biatrial enlargement:

• 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).

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References

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Advanced Reading

Online

Textbooks

• Zimmerman FH. ECG Core Curriculum. 2023
• Mattu A, Berberian J, Brady WJ. Emergency ECGs: Case-Based Review and Interpretations, 2022
• Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
• Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
• Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
• Hampton J, Adlam D. The ECG Made Practical 7e, 2019
• Kühn P, Lang C, Wiesbauer F. ECG Mastery: The Simplest Way to Learn the ECG. 2015
• Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
• Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
• Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004

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LITFL Further Reading

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