Nonspecific Intraventricular Conduction Delay

A nonspecific intraventricular conduction delay (IVCD) is characterized by a wide complex QRS (>120ms) from a supraventricular rhythm (including normal sinus) that does not produce characteristics of a RBBB or a LBBB. Although this block can occur from primary cardiac disease, metabolic or toxicologic disturbances are some of the more common causes of this. Evaluation of ischemia still requires use of the modified Sgarbossa criteria as these depolarization abnormalities will also produce repolarization abnormalities (following appropriate discordance).

Further Reading:

http://hqmeded-ecg.blogspot.com/2014/02/prolonged-chest-pain-and.html