Intracardiac mapping of atrial arrhythmias in humans: development and validation of new techniques

Student thesis: Doctoral ThesisDoctor of Philosophy


In patients undergoing catheter ablation procedures for atrial tachycardia, successful ablation requires the mechanism and location of the tachycardia to be correctly determined. This thesis explores the integration of engineering and computational methods with electrophysiological principles for mapping atrial tachycardias.

The first objective of the thesis is to re-evaluate activation mapping. Ripple Mapping was created for this purpose. This is a method that displays each recorded electrogram as a bar on the shell that represents the cardiac surface: the length of the bar varies with time according to the electrogram voltage-time relationship. A proof-of-concept study evaluates Ripple Mapping in a small number of patients with a variety of different arrhythmias. After further development of the method, it is evaluated in patients with atrial tachycardia. Benefits include avoiding the need to annotate each electrogram with a Local Activation Time and also avoiding the need to select a Window of Interest.

The second objective is to investigate how macro-reentry tachycardias are detected. The classic entrainment criteria can be difficult to apply in the clinical setting of atrial tachycardia (particularly after prior ablation). A new entrainment criterion is described that utilises the response to entrainment from multiple locations. This can also detect double loop reentry from two entrainment manoeuvres. The theoretical basis for the criterion is developed within a mathematical framework. Clinical testing is performed in patients with typical flutter, left atrial macroreentry, and also analysis of previously published reports of double-loop reentry. The criterion is also incorporated into the overdrive pacing analysis software described below.

The final objective was to integrate information from overdrive pacing manoeuvres in combination with the electroanatomic information from 3D mapping systems. A theoretical basis for this has been developed and incorporated into a computer program. Initial clinical evaluation is presented from patients with simulated focal tachycardias as well as clinical localised reentrant and macroreentrant tachycardias.

Date of Award2014
Original languageEnglish
Awarding Institution
  • King's College London
SupervisorMark O'Neill (Supervisor) & Reza Razavi (Supervisor)

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