Pace mapping of arrhythmias

Pace mapping of arrhythmias

The two common methods of mapping cardiac arrhythmias are activation mapping and pace mapping. In activation mapping, spontaneous or induced tachycardia is mapped to detected the earliest activation site, which is targeted for ablation. When the tachycardia is difficult to induce, pace mapping is useful. It can also corroborate the findings of activation mapping. Pace mapping at potential ablation sites is done at a rate slightly faster than the ventricular tachycardia. The QRS morphology should be a 12/12 match of the clinical tachycardia or ventricular premature complexes. It should be an exact replica including any small notches, indicating that the stimulation is being performed at the exact site of the ectopic impulse formation. Ablation from such perfect pacemap sites are usually successful. But when the match is less (e.g. 10/12 lead match), the chance of success is less. As little current as needed to reliably capture is to be used for pace mapping. If the current needed for capture is more than 5 mA, the electrode contact is poor and needs adjustment.