Preferential conduction across the ventricular outflow septum in ventricular arrhythmias originating from the aortic sinus cusp.
OBJECTIVE
The purpose of this study was to examine the relationship between the origin and breakout site of idiopathic ventricular tachycardia (VT) or premature ventricular contractions (PVCs) originating from the myocardium around the ventricular outflow tract.


BACKGROUND
The myocardial network around the ventricular outflow tract is not well known.


METHODS
We studied 70 patients with idiopathic VT (n = 23) or PVCs (n = 47) with a left bundle branch block and inferior QRS axis morphology. Electroanatomical mapping was performed in both the right ventricular outflow tract (RVOT) and aortic sinus cusp (ASC) during VT or PVCs.


RESULTS
The earliest ventricular activation (EVA) was recorded in the RVOT in 55 patients (group R) and in the ASC in 15 (group A). In all group R patients, the closest pace map and successful ablation were achieved at the EVA site. Although a successful ablation was achieved at the EVA site in all group A patients, the closest pace map was obtained at the EVA site in 8 and RVOT in 7 (with an excellent pace map in 4). The stimulus to QRS interval was 0 ms during pacing from the RVOT and 36 +/- 8 ms from the ASC. The distance between the EVA and perfect pace map sites in those 4 patients was 11.9 +/- 3.0 mm.


CONCLUSIONS
Ventricular arrhythmias originating from the ASC often show preferential conduction to the RVOT, which may render pace mapping or some algorithms using the electrocardiographic characteristics less reliable. In some of those cases, an insulated myocardial fiber across the ventricular outflow septum may exist.
Yamada
Takumi
T
Division of Cardiovascular Diseases, Cardiac Rhythm Management Laboratory, University of Alabama at Birmingham, VH B147, 1670 University Boulevard, 1530 3rd Avenue South, Birmingham, Alabama 35294-0019, USA. takumi-y@fb4.so-net.ne.jp
Murakami
Yoshimasa
Y
Yoshida
Naoki
N
Okada
Taro
T
Shimizu
Takeshi
T
Toyama
Junji
J
Yoshida
Yukihiko
Y
Tsuboi
Naoya
N
Muto
Masahiro
M
Inden
Yasuya
Y
Hirai
Makoto
M
Murohara
Toyoaki
T
McElderry
Hugh T
HT
Epstein
Andrew E
AE
Plumb
Vance J
VJ
Kay
G Neal
GN
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D006329:Heart Conduction System / Q000503:physiopathology*; D006346:Heart Septum / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D012850:Sinus of Valsalva / Q000503:physiopathology*; D017180:Tachycardia, Ventricular / Q000503:physiopathology*; D018879:Ventricular Premature Complexes / Q000503:physiopathology*