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Electrocardiography is a useful adjunct to other pulmonary tests because it provides information about the right heart (see Cardiovascular Tests and Procedures: Echocardiography).
Chronic pulmonary hypertension leading to chronic right atrial and ventricular hypertrophy may manifest as prominent P waves (P pulmonale) and ST-segment depression in leads II, III, and aVF; rightward shift in QRS axis; and decreased progression of R waves in precordial leads. COPD patients commonly have low voltage due to interposition of hyperexpanded lungs between the heart and ECG electrodes.
Acute right ventricle overload or failure, as occurs in submassive or massive pulmonary embolism, manifests as right axis deviation (R > S in V1), with S-wave deepening in lead I, Q-wave deepening in lead III, and ST-segment elevation and T-wave inversion in lead III and the precordial leads (S1Q3T3 pattern). Right bundle branch block also sometimes occurs.
Last full review/revision November 2005
Content last modified November 2005
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