A 58 year old woman was referred to our centre for aortic valve replacement because of a severe symptomatic aortic stenosis. She had no coronary risk factors. Rest ECG showed complete left bundle branch block. Coronary angiography showed normal coronary anatomy (fig 1). The gradient over the aortic valve could not be measured because of repetitive iatrogenic induction of ventricular tachycardia on inserting the catheter into the left ventricle. Non-invasive evaluation showed an echo Doppler gradient of 70 mm Hg and an aortic valve area of 1.2 cm² with normal left ventricular function. The patient was scheduled for aortic valve replacement.