Editor’s Perspective: Electrocardiogram Mapping–Reentry
To be consistently successful, the interventional electrophysiologist must thoroughly study the electrocardiogram (ECG) of a patient before any catheter ablation procedure. The principles for ECG localization of an arrhythmia include analyzing the axis, timing of the intrinsicoid deflection, and identifying a lead where the inscribed deflection is completely negative. These analyses are equally relevant when analyzing the P wave of atrial arrhythmias and the QRS complex of ventricular arrhythmias.
Article see p 755
In general, identifying the site of origin for an automatic tachycardia or the site of early ventricular activation from an accessory pathway can be deduced in a fairly straightforward manner by analyzing the routine electrocardiographic leads. For example, during ventricular tachycardia, a complete negative (QS complex) in lead I strongly suggests origin in the left side of the body and further often signifies epicardial origin because there is no vector of activation that proceeds toward the left shoulder. Using all leads available can usually localize the site of arrhythmia origin to a fairly localized area of atrial or ventricular myocardium.
ECG and Reentry
The principles of using the P wave or QRS to map the site of origin of arrhythmia are based on a discrete initiating site followed by relatively predictable and uniform conduction to the rest of the respective cardiac chamber. With macroreentry, there is neither a site of origin nor an expectation for predictable subsequent …