Precordial concordance, also known as QRS concordance, is a pattern in which all

precordial In anatomy, the precordium or praecordium is the portion of the body over the heart and lower chest.leads Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

on an electrocardiogram are either positive (positive concordance: all the major spikes point upwards from the baseline) or negative (negative concordance: point downwards). When there is a negative concordance, it almost always represents a life-threatening condition called

ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a cardiovascular disorder in which fast heart rate occurs in the ventricles of the heart. Although a few seconds of VT may not result in permanent problems, longer periods are dangerous; and multiple ...

because there is no other condition that suggests any abnormal

conduction Conductor or conduction may refer to: Biology and medicine * Bone conduction, the conduction of sound to the inner ear * Conduction aphasia, a language disorder Mathematics * Conductor (ring theory) * Conductor of an abelian variety * Condu ...

from the apex of the heart to the upper parts. However, in positive concordance another rare conditions such as left side

accessory pathway In cardiology, an accessory pathway is an additional electrical connection between two parts of the heart. These pathways can lead to abnormal heart rhythms ( arrhythmias) associated with symptoms of palpitations. Some pathways may activate a regi ...

s or blocks are also possible.

References

Electrophysiology Physiology {{med-imaging-stub