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Left Atrial Enlargement
Left atrial enlargement (LAE) is due to pressure or volume overload of the left atrium. LAE is often a precursor to atrial fibrillation.
Also known as: Left Atrial Enlargement (LAE), Left atrial hypertrophy (LAH), left atrial abnormality.
P wave changes with Left Atrial Enlargement
ECG Criteria for Left Atrial Enlargement
LAE produces a broad, bifid P wave in lead II (PÂ mitrale) and enlarges the terminal negative portion of the P wave in V1.
In lead II
- Bifid P wave with > 40 ms between the two peaks
- Total P wave duration > 110 ms
In V1
- Biphasic P wave with terminal negative portion > 40 ms duration
- Biphasic P wave with terminal negative portion > 1mm deep
Causes of left atrial hypertrophy
In isolation:
- Classically seen with mitral stenosis
In association with left ventricular hypertrophy:
- Systemic hypertension
- Aortic stenosis
- Mitral incompetence
- Hypertrophic cardiomyopathy
ECG Examples
Example 1
- Broad (>110ms), bifid P wave in lead II (P mitrale) with > 40ms between the peaks
Example 2
P wave terminal portion > 40 ms duration in V1
Example 3
P waves with terminal portion > 1mm deep in V1
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Right Atrial Enlargement
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ECG Criteria of Right Atrial Enlargement
Right atrial enlargement produces a peaked P wave (P pulmonale) with amplitude:
- > 2.5 mm in the inferior leads (II, III and AVF)
- > 1.5 mm in V1 and V2
Also known as: Right Atrial Enlargement (RAE), Right atrial hypertrophy (RAH), right atrial abnormality
P wave changes with Right Atrial Enlargement
Causes of Right Atrial Enlargement
The principal cause is 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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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
In V1
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
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
- Hypertension
- Aortic stenosis
- Mitral incompetence
- Hypertrophic cardiomyopathy (HOCM)
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