EXPERIMENTAL EVIDENCE OF VENTRICULAR ARRHYTHMIAS SUSCEPTIBILITY IN DIFFERENT ANIMAL MODELS

Aim

Among the animal models used in preclinical cardiology, the porcine one is the most accepted. It has widely replaced the canine model because of its similarity to the human heart anatomy and the ethical restrictions. Anatomical differences of the pig conductive system, with respect to the canine and human ones, are considered to be the cause of important electrophysiological properties, such as the susceptibility to ventricular arrhythmias (VAs).

Material and Methods

We analyzed a group of 6 pigs (FNUSA-ICRC, Veterinary and Pharmaceutical University /VFU/ Brno, CZ) and 6 mongrel dogs (Mayo Clinic, Rochester, USA) in which we performed endocardial and epicardial radiofrequency ablation (RFA, in total 62 and 41 applications respectively), while reporting the occurrence of spontaneous arrhythmias during the procedures. Other analyzed parameters were ablation power, duration, site (right and left ventricle) and device type (fork and finger catheter). A quasi binomial variance was assumed for absence or presence of VAs over the RFAs. Experiment was approved by Ethical Committee of VFU.

Results

Mean power and duration of Radiofrequency ablation (RFA) application when arrhythmia was not elicited were 36.52 ± 2.35 W, 111.25 ± 5.03 s and 31.69 ± 2.36 W, 49.16 ± 5.05 s (for dogs and pigs, respectively). Odds ratio (OR) estimated for porcine model showed almost five-fold susceptibility of VAs than canine one during RFA (OR 4.8201 vs. 1.5728; p=0.0101). Results were solely imputable to the investigated species, not to other ablation parameters.

Conclusion

Our work has shown that pigs are significantly more susceptible to ventricular arrhythmias than the dogs. This fact may limit the application of porcine model and should be taken under consideration during experiments designing.