Background: Mapping of regular cardiac arrhythmias is frequently performed using sequential point-by-point annotation of local activation relative to a fixed timing reference. Assigning a single activation for each electrogram is unreliable for fragmented, continuous, or double potentials. Furthermore, these informative electrogram characteristics are lost when only a single timing point is assigned to generate activation maps.
Objective: The purpose of this study was to develop a novel method of electrogram visualization conveying both timing and morphology as well as location of each point within the chamber being studied.
Methods: Data were used from six patients who had undergone electrophysiological study with the Carto electroanatomic mapping system. Software was written to construct a three-dimensional surface from the imported electrogram locations. Electrograms were time gated and displayed as dynamic bars that extend out from this surface, changing in length and color according to the local electrogram voltage-time relationship to create a ripple map of cardiac activation.
Results: Ripple maps were successfully constructed for sinus rhythm (n = 1), atrial tachycardia (n = 3), and ventricular tachycardia (n = 2), simultaneously demonstrating voltage and timing information for all six patients. They showed low-amplitude continuous activity in four of five tachycardias at the site of successful ablation, consistent with a reentrant mechanism.
Conclusion: Ripple mapping allows activation of the myocardium to be tracked visually without prior assignment of local activation times and without interpolation into unmapped regions. It assists the identification of tachycardia mechanism and optimal ablation site, without the need for an experienced computer-operating assistant.