Background: Cryoablation is effective for not only ablating the myocardium, but also maintaining the structure of the ablated tissue. However, data comparing nitrous oxide (N2O)-based and argon gas-based cryoprobes are limited.
Methods: This study was a follow-up study of a single-center, prospective, randomized controlled trial in which 60 patients were randomly allocated to either the N2O group or the argon group. The primary endpoint of this study was sinus rhythm maintenance, and the key secondary endpoint was a composite of major adverse cardiovascular and cerebrovascular events (MACCEs) (ie, cardiac death, stroke, major bleeding, and readmission for heart failure).
Results: The baseline and operative characteristics of the patients in the N2O and argon groups were comparable. At the 5-year follow-up, the rate of sinus rhythm maintenance was 81.8% in the N2O group, whereas it was 78.5% in the argon group (P > .999). No significant differences in the rate of freedom from MACCEs (80.6% in the N2O group vs 81.9% in the argon group; P = .978) were observed at the 5-year follow-up. The left atrial volume index decreased over time from 114.65 mL/m2 to 65.74 mL/m2 (P < .0001) and reached similar values in the 2 groups (P = .279) at the 5-year follow-up.
Conclusions: Both N2O- and argon gas-based cryoprobes showed similar rates of sinus rhythm maintenance and freedom from MACCEs at the 5-year follow-up. Both cryoprobes might have similar efficacy and safety in the arrested heart in the long term.
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