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Assessment of irrigated-tip radiofrequency catheter ablation lesion characteristics using different irrigation fluids on ex-vivo bovine myocardium

Certain arrythmias, particularly of ventricular origin, necessitate deep lesions in order to achieve clinical success. The introduction of irrigated-tip radiofrequency (RF) catheters has allowed creation of deeper lesions and has decreased char formation. Although normal saline has been used as a standard solution, recent observations have suggested less ionic solutions may increase lesion depth. In this in-vitro study we aimed to characterize lesions created by irrigated-tip RF catheters using standard normal saline(NS), half-normal saline (HNS), and HNS-%2.5Dextrose (HNS-DEX/2) combination solutions.

Bovine myocardium was placed firstly in ringer-lactate bath. Using irrigated-tip RF catheter ablation lesions were created serially using 30, 40, 50, 60, 70Watts with NS, HNS and HNS-DEX/2 as irrigation solutions. Lesion depths, steam pops and impedance drops were measured. Subsequently the experiment was repeated in normal saline bath.

Both HNS-DEX/2 and HNS irrigation solutions increase lesion depths when compared to normal saline (Table 1, Figure 1). Steam pops were more common and earlier with HNS-DEX/2 and HNS.

Our findings suggest that less ionic irrigation solutions lead to increased lesion depths using similar RF power. If confirmed in-vivo, HNS and, particularly, HNS-DEX/2 as irrigation solution may increase ablation success for intramural/deep myocardial arrhythmic foci. Additionally, studies to assess safety of this strategy are necessary as intuitively deeper lesions may lead to more complications.

Table 1

Abstract Figure 1