Endocardial Contact Mapping Using Multipolar Basket Electrode Catheters

Abstract

The most commonly used method for cardiac mapping has changed little in principle from that developed by early pioneers almost a century ago. A single exploring electrode collects temporal data over an imaginary spatial grid projected onto a surface of the heart. Local activation times, referenced to the surface ECG are then collected sequentially over a time period that may measure ten minutes or more. A further ten to fifteen minutes may be required to collate the temporal data so as to produce a stereotypical isochronal map of activation. This process is predicated on the sequence of activation being precisely reproduced with each heart beat throughout the mapping procedure. When this process is applied to ventricular tachycardias, a major limitation is that the tachycardia must be sustained, without change or hemodynamic compromise for the duration of the mapping period. In practice this means that tachy-arrhythmias that fluctuate in morphology or cycle length and those that are unstable hemodynamically, can not be adequately mapped by a roving catheter.