Biatrial radiofrequency ablation significantly reduced the estimated atrial contribution to cardiac output from 18% before to 5% after ablation (P<0.01), indicating impaired atrial contractility.
Does biatrial radiofrequency ablation designed to cure atrial fibrillation impair atrial mechanical function in dogs?
Multiple linear radiofrequency lesions in the atria designed to cure atrial fibrillation significantly impair atrial contractility and mechanical function in a canine model.
Absolute Event Rate: 5% vs 18%
p-value: p=<0.01
INTRODUCTION: The effects of linear radiofrequency lesions in the atria for cure of atrial fibrillation on atrial contraction have not previously been quantified. METHODS AND RESULTS: Atrial function was measured before and 30 +/- 24 days after a biatrial ablation procedure designed to cure atrial fibrillation in eight dogs and after a sham procedure in three dogs. Atrial mechanical function was assessed using Doppler diastolic blood flow velocities, atrial systolic pressure wave amplitude, and assessment of atrial contribution to cardiac output estimated by comparison of AV sequential pacing to ventricular pacing at the same heart rate. The mitral Doppler A/E velocity ratio was 1.03 +/- 0.45 before and 0.72 +/- 0.43 after ablation (P = 0.048). The tricuspid A/E ratio was 0.88 +/- 0.17 before and 0.71 +/- 0.12 after ablation (P = 0.04). The estimated atrial contribution to cardiac output was 18% +/- 9% before and 5% +/- 4% after ablation (P < 0.01). The left atrial systolic pressure wave amplitude was 2.8 +/- 1.5 mmHg before and 1.7 +/- 1.0 mmHg after ablation (P = 0.1). These changes were not observed in control dogs. Lesions covered 25% +/- 6% of the atrial endocardial surface. CONCLUSION: Multiple linear radiofrequency lesions in the atria designed to cure atrial fibrillation may impair atrial contractility. Reduced atrial function is partly due to loss of atrial myocardial mass, but regional delays in atrial activation and splinting of the atria by scarring also may contribute.
Thomas et al. (Sat,) conducted a other in Atrial fibrillation (n=11). Biatrial radiofrequency ablation vs. Sham procedure / Baseline was evaluated on Atrial contribution to cardiac output (p=<0.01). Biatrial radiofrequency ablation significantly reduced the estimated atrial contribution to cardiac output from 18% before to 5% after ablation (P<0.01), indicating impaired atrial contractility.
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