Mechanical interruption of postinfarction ventricular tachycardia as a guide for catheter ablation.
BACKGROUND
Mechanical trauma has been described as a helpful guide for ablation of atrial tachycardias and accessory pathways. In postinfarction ventricular tachycardia (VT), the reentrant circuit is partly endocardial and therefore may be susceptible to catheter trauma.


OBJECTIVE
The purpose of this study was to determine the prevalence and significance of VT termination resulting from catheter trauma.


METHODS
A consecutive series of 39 patients (mean age 68 +/- 7 years, ejection fraction 0.25 +/- 0.02) underwent left ventricular mapping for postinfarction VT. Mapping was performed during 62 hemodynamically tolerated VTs (mean cycle length 451 +/- 88 ms). Only hemodynamically tolerated VTs that did not terminate spontaneously and VTs that were reproducibly inducible were included in the study. VT termination was considered mechanical only if it was not caused by a premature depolarization.


RESULTS
In 13 of 62 VTs (21%) in 8 of 39 patients (21%), either VT terminated during catheter placement at a particular site (n = 7) or a previously reproducibly inducible VT became no longer inducible with the mapping catheter located at a particular site (n = 6). The stimulus-QRS interval was significantly shorter at sites where mechanical trauma affected the reentrant circuit compared with sites having concealed entrainment (102 +/- 56 ms vs 253 +/- 134 ms, P = .003). At the site that was susceptible to mechanical trauma, the pace map was identical or highly similar in 13 of 13 VTs. After radiofrequency ablation at these sites, the targeted VTs were no longer inducible. No patient had recurrence of the targeted VT during a mean follow-up of 15 +/- 11 months.


CONCLUSIONS
Catheter contact at a critical endocardial site can interrupt postinfarction VT or prevent its induction. Radiofrequency ablation at sites of mechanical termination of VT has a high probability of success.
Division of Cardiology, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0366, USA. fbogun@umich.edu
Frank
F
Bogun
Eric
E
Good
Jihn
J
Han
Kamala
K
Tamirisa
Stephen
S
Reich
Darryl
D
Elmouchi
Petar
P
Igic
Kristina
K
Lemola
Hakan
H
Oral
Aman
A
Chugh
Frank
F
Pelosi
Fred
F
Morady
D000368:Aged; D017115:Catheter Ablation / Q000379:methods*; D004566:Electrodes; D004699:Endocardium / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications*; D010812:Physical Stimulation; D011446:Prospective Studies; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery*