Improved safety of PVI procedures with shorter clotting times
REDWOOD CITY, CALIFORNIA. Anticoagulation during catheter ablation needs to be precisely controlled. Too little anticoagulant (usually heparin) and blood clots may form on the catheter or sheaths, too much and the risk of hematoma and serious bleeding complications increase. The degree of anticoagulation achieved is measured as "Activated Clotting Time" or ACT with increasing values corresponding to increased anticoagulation. The usual target value is 300 to 350 seconds or longer. Now a team of electrophysiologists at the Sequoia Hospital reports that ACT can safely be reduced to 225 seconds if an open tip irrigated catheter is used for ablation.

The Sequoia study covered 1122 ablations performed on 843 patients (average age of 62 years). The majority of patients were male (72%) and 32% had paroxysmal AF, 50% had persistent, and 18% permanent. The ablations were carried out between October 10, 2003 and December 31, 2009. The open tip irrigated catheter was introduced in January 2006 after which the team gradually reduced ACT from more than 350 seconds to about 225 seconds. The percentages of serious procedure-related complications at various ACTs (ranges shown in seconds) are shown below:
* Requiring transfusion or surgery

The overall complication rate using an open tip irrigated catheter and an ACT of less than 250 seconds (average 224 seconds) compares favourably with rates of 2.7 to 3.9% reported in recent surveys. The authors noted that women tended to have higher blood levels of heparin and higher ACTs than men for equivalent doses of heparin. This could explain why women tend to have more bleeding complications during catheter ablation and calls for greater care in adjusting heparin infusion when women are ablated.

Winkle, RA, et al. Safety of lower activated clotting times during atrial fibrillation ablation using open irrigated tip catheters and a single transseptal puncture. American Journal of Cardiology, Vol. 107, No. 5, March 1, 2011, pp. 704-08

Editor's comment: The finding that ACT can be safely decreased when using an open tip irrigated catheter is obviously of significant importance and its general implementation should help reduce procedure-related bleeding complications, especially in female ablatees.