The spectrum of P-wave changes in leads II and V1 with right, left and bi-atrial enlargement is summarised in the following diagram:
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.
In lead II
Bifid P wave with:
- Amplitude ≥ 2.5mm
- Duration ≥ 120 ms
Biphasic P waves with:
- Initial positive deflection ≥ 1.5mm tall
- Terminal negative deflection ≥ 1mm deep
- Terminal negative deflection ≥ 40 ms duration
- P wave positive deflection ≥ 1.5 mm in leads V1 or V2
- Notched P waves with duration >120 ms in limb leads, V5 or V6
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
Left Atrial Enlargement
- 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]. Accessed 12/12/2011.
- 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. Review. PubMed PMID: 12028984; PubMed Central PMCID: PMC1123219 [Full Text].
- Harrigan RA, Jones K. ABC of clinical electrocardiography. Conditions affecting the right side of the heart. BMJ. 2002 May 18;324(7347):1201-4. Review. PubMed PMID: 12016190; PubMed Central PMCID: PMC1123164 [Full Text].
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