Canine models of long-duration ventricular fibrillation exhibited predominantly endocardial-to-epicardial propagation, differing markedly from porcine models.
Does the transmural activation sequence during long-duration ventricular fibrillation differ between pigs and dogs?
The transmural activation sequence during long-duration ventricular fibrillation differs markedly between pigs and dogs, suggesting dogs are a better model for human LDVF.
BACKGROUND: Humans are more similar in transmural Purkinje and cardiac ion channel distributions to dogs than pigs. The Purkinje network in pigs is transmural but confined to the endocardium in dogs. Little is known about intramural activation during long-duration ventricular fibrillation (LDVF) given these differences. We tested the hypothesis that the transmural activation sequence is similar in sinus rhythm (SR) and LDVF in dogs as well as pigs, but different between species. METHODS AND RESULTS: In six pigs and seven dogs, 50-60 plunge needles (six electrodes, 2-mm spacing) were placed throughout the left ventricle. Unipolar recordings were made for >10 minutes of LDVF. SR and LDVF activation times were grouped into waves by linking activations along each needle. Origin (earliest activation) and propagation direction were determined for each wave. The mean wave origin was significantly more endocardial in dogs than pigs for SR and 1 through 10 minutes of LDVF. Predominant propagation direction in LDVF and SR was endocardial to epicardial in dogs, but the opposite or equal in both directions in pigs. Fastest activation rate was epicardial in pigs, but endocardial in dogs with an increasing endocardial-to-epicardial activation rate gradient as LDVF progressed in dogs but not pigs. CONCLUSIONS: The transmural activation sequence in SR and LDVF is markedly different between pigs and dogs. These differences may be related to differences in Purkinje fiber and ion channel distributions and suggest that dogs are a better model for investigating activation sequences during LDVF, given the similarities with humans.
Allison et al. (Thu,) conducted a other in Long-duration ventricular fibrillation (n=13). Long-duration ventricular fibrillation vs. Pigs vs Dogs was evaluated on Transmural activation sequence (origin, propagation direction, and activation rate). Canine models of long-duration ventricular fibrillation exhibited predominantly endocardial-to-epicardial propagation, differing markedly from porcine models.
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