Emerging 3-D Mapping Systems for Diagnosi and Management of Arrhythmias

Three-dimensional (3-D) mapping systems have been developed and used for more than 20 years to map more complex arrhythmias that cannot easily be treated with traditional electrophysiological approaches. These systems allow 3-D reconstruction of cardiac chamber anatomy, with recording and display of intracardiac electrograms at each point on the chamber surface. Activation maps display propagation of wavefronts to identify focal pattern (earliest site with centrifugal activation) and macroreentrant pattern (continuous activation with total activation time equal to tachycardia cycle length). Voltage maps demonstrate regions of healthy (normal and high voltage) and diseased/scarred myocardium (low voltage) and anatomical boundaries. Image integration with computed tomography scan, magnetic resonance and intracardiac echocardiography into the mapping systems facilitates reconstruction of cardiac chamber anatomy. The recent introduction of contact force sensors into mapping/ablation catheters has also improved the accuracy of reconstruction of chamber geometry.

A fundamental limitation of most currently available 3-D mapping systems is the requirement of manual correction of annotation of activation time, especially for complex electrograms (i.e. low amplitude potentials, multiple potentials or fractionated electrograms). In order to overcome this limitation, three new systems have been developed: 1) ultra, high-resolution mapping system; 2) ripple mapping system; and 3) close-unipolar activation vector mapping system, allowing automatic identification of the mechanism of complex arrhythmias (both focal and macroreentrant) and localizing arrhythmogenic foci and entire reentrant circuits with arrhythmogenic channels. The ability to acquire activation and voltage map information from multiple electrodes simultaneously with accurate localization of each mapped point in 3-D space allows rapid data acquisition, facilitating catheter mapping and ablation in patients with complex arrhythmias. Comparison with optical mapping data of membrane action potential in animal models contributes to basic understanding of information obtained by these mapping methods.