Internal atrial shock delivery by standard diagnostic electrophysiology catheters in goats: effects on atrial electrogram amplitude and tissue architecture.

AIMS

In this study, we evaluated the effects of atrial shock delivered via diagnostic electrophysiology catheters.

METHODS AND RESULTS

In 11 anaesthetized goats, decapolar catheters were positioned in the right atrial appendage (RAA) and coronary sinus (CS). Three different catheters and two cardioversion protocols were evaluated. In four goats, 50 J shocks were delivered using catheters with 1 mm electrodes (surface area 70 mm(2)). In 6 goats, catheters with 2 mm electrodes (area 140 mm(2)) were used. In three of the six goats, 50 J shocks were given while in the other 3, 10 J shocks were delivered. In 1 goat 50 J shocks were delivered via 5 mm electrode catheters (area 310 mm(2)). No persisting adverse effects occurred. However, the electrogram amplitude at the RAA and CS decreased by >50-98% (P > 0.01). The amount of amplitude decrease was most pronounced at the CS site and for 50 J shocks. Goats were sacrificed after 9 +/- 1 days. Macroscopy revealed endocardial lesions at the electrode locations. Microscopy showed endocardial thrombosis, and necrosis with formation of granulation tissue. Changes were most marked with diagnostic catheters and 50 J shocks.

CONCLUSIONS

Atrial shock delivery via diagnostic catheters causes local ablation lesions. The amount of amplitude decrease, macroscopic and microscopic damages were related to the energy applied and electrode surface area.