The pitfalls of automatic point acquisition with high-resolution mapping

An 81-year-old man with a typical atrial flutter underwent cavo-tricuspid isthmus (CTI) ablation. After the creation of wide planar lesion at the CTI, a high-resolution activation map with Rhythmia™ (Boston Scientific, Cambridge, MA, USA) was acquired during lateral right atrium pacing, which demonstrated a centrifugal activation at the septal side of ablation line. A review of points acquired at the earliest activation site demonstrated that perivalvular premature ventricular contractions (PVCs) at tricuspid annulus had been inappropriately acquired as atrial electrograms. This mis-acquisition was explained by the following: (i) no change in the beat acceptance criteria of the propagation reference in the coronary sinus due to the absence of ventriculoatrial conduction of mechanical PVCs, and (ii) failure to reject beats overlapping the PVCs because those voltages did not reach the threshold of 0.64 mV. When the mapping system shows centrifugal activation over the linear lesion, passive activation from the epicardial structures or the other chamber is an important differential diagnosis; however, mis-annotation due to automated acquisition must be also ruled out. It is important to understand the automated point-acquisition criteria in each mapping system and to be familiar with the pitfalls of the criteria.

The evolution of ultra-high-resolution mapping technology enables us to understand the details of tachycardia circuit with much fewer manual reannotations. The criteria for automatic point acquisition installed in the mapping system usually works effectively, resulting in a demonstration of a precise tachycardia circuit. However, the present case logically showed how we noticed the mis-annotation of the high-resolution activation map and explained the pitfall of the function of automatic beat acquisition.