Chronic atrial fibrillation in a canine model significantly decreased left atrial mean bipolar amplitude from 5.96 mV at baseline to 3.23 mV (P<.01), alongside increased dominant frequency and fibrosis.
Does long-term chronic AF induced by neurostimulation alter atrial electrophysiological and structural substrate in a canine model?
In a canine model, chronic AF leads to significant decreases in intracardiac bipolar amplitudes and increases in dominant frequency and tissue fibrosis, though amplitudes remain higher than traditional cut-offs for diseased tissue.
Tasa de eventos absoluta: 3.23% vs 5.96%
valor p: p=<.01
BACKGROUND: Atrial fibrillation (AF) is related to numerous electrophysiological changes; however, the extent of structural and electrophysiological remodeling with long-term AF is not well characterized. METHODS: Dogs (n = 6) were implanted with a neurostimulator in the right atrium (AF group). No implantation was done in the Control group (n = 3). Electroanatomical mapping was done prior to and following more than 6 months of AF. Magnetic resonance imaging was also done to assess structural remodeling. Animals were euthanized and tissue samples were acquired for histological analysis. RESULTS: , P = .01). Also, mean bipolar amplitude in the LA significantly decreased from 5.96 ± 2.17 mV at baseline to 3.23 ± 1.51 mV (P < .01) after chronic AF. Those significant changes occurred in each anterior, lateral, posterior, septal, and roof regions as well. Additionally, the dominant frequency (DF) in the LA increased from 7.02 ± 0.37 Hz to 10.12 ± 0.28 Hz at chronic AF (P < .01). Moreover, the percentage of fibrosis in chronic AF animals was significantly larger than that of control animals in each location (P < .01). CONCLUSIONS: Canine chronic AF is accompanied by a significant decrease in intracardiac bipolar amplitudes. These decreased electrogram amplitude values are still higher than traditional cut-off values used for diseased myocardial tissue. Despite these "normal" bipolar amplitudes, there is a significant increase in DF and tissue fibrosis.
Yamashita et al. (Sat,) conducted a other in Atrial fibrillation (n=9). Neurostimulator implantation (AF induction) vs. Baseline / No implantation was evaluated on Mean bipolar amplitude in the left atrium (p=<.01). Chronic atrial fibrillation in a canine model significantly decreased left atrial mean bipolar amplitude from 5.96 mV at baseline to 3.23 mV (P<.01), alongside increased dominant frequency and fibrosis.