 Precordial concordance

Precordial concordance, also known as QRS concordance is when all precordial leads on an electrocardiogram are either positive (positive concordance) or negative (negative concordance).When there is a negative concordance, it almost always represents a life-threatening condition called ventricular tachycardia because there is no other condition that suggests any abnormal conduction from the apex of the heart to the upper parts.