Importance of recording lead V1 in the seventh right intercostal space in diagnosing corpulmonale

Right-sided chest leads V1 to V6R were recorded in the 4th to 7th intercostal spaces in 25 cases of corpulmonale secondary to chronic obstructive pulmonary disease and in an equal number of age-matched controls. Results were compared with findings in the conventional electrocardiogram. Chest leads recorded in the seventh right intercostal space along the right sternal border could detect 24% of cases of corpulmonale that were missed by conventional leads.