Conditions affecting the right side of the heartBMJ 2002; 324 doi: https://doi.org/10.1136/bmj.324.7347.1201 (Published 18 May 2002) Cite this as: BMJ 2002;324:1201
- Richard A Harrigan,
- Kevin Jones
Many diseases of the right side of the heart are associated with electrocardiographic abnormalities. Electrocardiography is neither a sensitive nor specific tool for diagnosing conditions such as right atrial enlargement, right ventricular hypertrophy, or pulmonary hypertension. However, an awareness of the electrocardiographic abnormalities associated with these conditions may support the patient's clinical assessment and may prevent the changes on the electrocardiogram from being wrongly attributed to other conditions, such as ischaemia.
This article discusses right atrial enlargement, right ventricular hypertrophy, and the electrocardiographic changes associated with chronic obstructive pulmonary disease, pulmonary embolus, acute right heart strain, and valvular heart disease
Right atrial enlargement
The forces generated by right atrial depolarisation are directed anteriorly and inferiorly and produce the early part of the P wave. Right atrial hypertrophy or dilatation is therefore associated with tall P waves in the anterior and inferior leads, though the overall duration of the P wave is not usually prolonged. A tall P wave (height ≥2.5 mm) in leads II, III, and aVF is known as the P pulmonale.
Diagnostic criteria for right ventricular hypertrophy
(Provided the QRS duration is less than 0.12 s)
Right axis deviation of +110° or more
Dominant R wave in lead V1
R wave in lead V1 ≥7 mm
ST segment depression and T wave inversion in leads V1 to V4
Deep S waves in leads V5, V6, I, and aVL
The electrocardiographic changes suggesting right atrial enlargement often correlate poorly with the clinical and pathological findings. Right atrial enlargement is associated with chronic obstructive pulmonary disease, pulmonary hypertension, and congenital heart disease—for example, pulmonary stenosis and tetralogy of Fallot. In practice, most cases of right atrial enlargement are associated with right ventricular hypertrophy, and this may be reflected in the electrocardiogram. The electrocardiographic features of right atrial enlargement …