J. Tebbenjohanns et al., SLOWING OF THE VENTRICULAR RATE DURING ATRIAL-FIBRILLATION BY ABLATION OF THE SLOW PATHWAY OF AV NODAL REENTRANT TACHYCARDIA, Journal of cardiovascular electrophysiology, 6(9), 1995, pp. 711-715
Influence of Slow Pathway Ablation on Atrial Fibrillation. Introductio
n: The mechanisms whereby radiofrequency catheter modification of AV n
odal conduction slows the ventricular response are not well defined. W
hether a successful modification procedure can be achieved by ablating
posterior inputs to the AV node or by partial ablation of the compact
AV node is unclear. We hypothesized that ablation of the well-defined
slow pathway in patients with AV nodal reentrant tachycardia would sl
ow the ventricular response during atrial fibrillation. Methods and Re
sults: In 34 patients with dual AV physiology and inducible AV nodal r
eentrant tachycardia, atrial fibrillation was induced at baseline and
immediately after successful slow pathway ablation and at 1-week follo
w-up. The minimal, maximal, and mean RR intervals during atrial fibril
lation increased from 353 +/- 76, 500 +/- 121, and 405 +/- 91 msec to
429 +/- 84 (P < 0.01), 673 +/- 161 (P < 0.01), and 535 +/- 98 msec (P
< 0.01), respectively. These effects remained stable during follow-up
at 1 week. The AV block cycle length increased from 343 +/- 68 msec to
375 +/- 60 msec (P < 0.05) immediately and to 400 +/- 56 msec (P < 0.
01) at 1-week follow-up. The effective refractory period of the AV nod
e prolonged from 282 +/- 83 msec to 312 +/- 89 msec and to 318 +/- 81
msec after 1 week (P < 0.05), respectively, Conclusion: This study sho
ws a decrease in ventricular response to pacing-induced atrial fibrill
ation after ablation of the slow pathway in patients with AV nodal ree
ntrant tachycardia. Since the AV nodal conduction properties could be
defined, this study supports the hypothesis that the main mechanism of
AV nodal modification in chronic atrial fibrillation is caused by abl
ation of posterior inputs to the AV node.