An initial fall in impedance of more than 10 ohms during radiofrequency catheter ablation was 78% sensitive and 88% specific for predicting subsequent evidence of tissue heating.
Observational (n=20)
Does an initial decrease in impedance predict subsequent evidence of tissue heating during radiofrequency catheter ablation?
An initial impedance drop of >10 ohms during RF ablation is a sensitive and specific predictor of effective tissue heating, suggesting continuous impedance monitoring can guide ablation therapy.
Radiofrequency catheter ablation of accessory pathways and the atrioventricular junction often requires multiple applications of energy. The inability to determine the effects of any given application on the underlying tissue may contribute to this problem. In the present study, impedance was monitored in 20 patients undergoing radiofrequency catheter ablation, and the relationship between an initial decrease in impedance and subsequent effects were examined. An initial fall in impedance of more than 10 omega was 78% sensitive and 88% specific for predicting subsequent evidence of tissue heating (interruption of conduction or an abrupt rise in impedance due to coagulum formation). In contrast, initial values of voltage, current, or impedance did not distinguish between effective and ineffective applications of radiofrequency energy. Continuous monitoring of impedance may facilitate radiofrequency catheter ablation.
Harvey et al. (1992) conducted an observational in Arrhythmias requiring radiofrequency catheter ablation (n=20). Impedance monitoring was evaluated on Evidence of tissue heating (interruption of conduction or abrupt rise in impedance due to coagulum formation). An initial fall in impedance of more than 10 ohms during radiofrequency catheter ablation was 78% sensitive and 88% specific for predicting subsequent evidence of tissue heating.
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