Risk of ventricular fibrillation by HFS in the coronary sinus
In Case 7, HFS within the CS inadvertently captured ventricular
myocardium leading to ventricular fibrillation (Figure 4A, B). Po et al.
advised against HFS delivered within 2 cm of the ventricle to avoid
inducing ventricular fibrillation.6 The CS runs along
the mitral annulus so that the catheter within the CS would be located
close to the ventricular myocardium. We carefully performed trial pacing
at 20 V before HFS to confirm the stimulus would not capture the
ventricle. However, the respiratory motion of the heart or ventricular
refractoriness due to rapid ventricular responses under ISP infusion
might result in either transient capture or loss of capture. Hence, the
ablation of AF-Nests might be an alternative to HFS within the CS.