Abstract
Twenty-four cases of single ventricle were seen at Guy''s Hospital and Southampton Chest Hospital. The electrical axis of the heart, the P waves, and the precordial leads were analysed in relation to the associated lesions in single ventricle. The cause of P mitrale or P pulmonale in single ventricle is thought to be related to the stroke volume of the left atrium and right atrium respectively. High voltage and the pattern of negative deflections across the chest are thought to be suggestive of single ventricle. No special precordial pattern could be correlated with the anatomy of the great vessels or with the presence or absence of pulmonary stenosis. Four cases had heart block.