Though absence of the septal q wave on a standard ECG was recognised by Willem Einthoven, this abnormality has received little attention. Nevertheless it is common in patients with coronary artery disease, and strongly associated with fibrosis of the septum with or without infarction. Furthermore, the associated disturbance of ventricular activation has clear mechanical consequences, impairing both systolic and diastolic left ventricular performance. Its structural, functional, and possible prognostic significance combined with ease of its detection all suggest that the cardiographic sign of absence of the septal q wave should be more widely recognised as a noninvasive marker of ventricular disease.