Catheter Contact Force and Electrograms

Until recently, there was no way of telling how firmly the tip of the catheter was in contact with the heart and how this contact was orientated. The electrical signals measured through the catheters, known as electrograms, are used to guide the sites and duration of ablation, but the effect of catheter contact and orientation on these signals in human heart muscle that is fibrillating is not known. New catheters have now been developed which can measure the force of contact at their tip: using these, the investigators will examine how contact force affects the electrical behaviour of heart muscle tissue in atrial fibrillation. The effect the force of contact has on the electrogram recorded will also be investigated. In so doing we hope to gain a better understanding of the relationship between tissue contact and the electrograms we measure and in so doing improve the safety and effectiveness of ablation procedures.

Hypothesis: Catheter contact force and orientation have a significant impact on the characteristics of bipolar electrograms in the fibrillating human atrium.