DOI DOI https://doi.org/10.1007/s00392-021-01843-w
Steam pops are a rare complication associated with radiofrequency (RF) ablation and are hard to predict. The aim of this study was to assess the influence of coverage between the RF ablation electrode and cardiac tissue on steam pop incidence and lesion size.
Methods
An ex vivo model using porcine cardiac preparations and contact force sensing catheters was designed to perform RF ablations at different coverage levels between the RF electrode and cardiac tissue. During coverage level I, only the distal part of the ablation electrode was in contact to tissue. During coverage level II half of the ablation electrode, and during coverage level III the entire ablation electrode was embedded in tissue. RF applications (n=60) at different coverage levels I-III were systematically performed using the same standardized ablation protocol.
Results
Ablations during coverage level III resulted in a significantly higher rate of steam pops (100%) when compared to ablations during coverage level II (10%) and coverage level I (0%), log rank p<0.001. Coverage level I ablations resulted in significantly smaller lesion depths, diameters, and impedance drops when compared to higher coverage level ablations, p<0.001 (Figure). There was no difference in applied contact force or energy between different coverage levels.
Conclusions
RF electrode - tissue coverage has a significant influence on both lesion size and steam pop incidence. The findings of this study provide a possible explanation for the occurrence of unexpected steam pops in clinical RF application. Coverage levels were largely predetermined by cardiac anatomy; high and low coverage levels were achieved using the same levels of contact force. Larger coverage levels resulted in significantly larger lesion dimensions and more steam pops.
https://dgk.org/kongress_programme/jt2021/aP991.html