Ventricular tachycardia with alternate ventriculo-atrial Wenckebach conduction due to two-level block

A 54-year-old patient was studied because of ventricular tachycardia following an inferior myocardial infarction. During one episode of non-sustained ventricular tachycardia a 9:4 alternating ventriculo-atrial Wenckebach block was noted. This was based upon a 2:1 block between the ventricles and the bundle of His and a 5:4 Wenckebach block between the bundle of His and the atria. Our study shows that alternate Wenckebach periods during ventriculo-atrial conduction may be caused by two or more levels of block in the ventriculo-atrial conduction system.