Idiopathic ventricular arrhythmias originating from the papillary muscles in the left ventricle: prevalence, electrocardiographic and electrophysiological characteristics, and results of the radiofrequency catheter ablation.
BACKGROUND
Idiopathic ventricular arrhythmias (VAs) can originate from the left ventricular (LV) papillary muscles (PAMs). This study investigated the prevalence, electrocardiographic and electrophysiological characteristics, and results of catheter ablation of these VAs, and compared them with other LV VAs.


RESULTS
We studied 71 patients with VAs originating from the LV anterolateral and posteroseptal regions among 159 patients undergoing successful catheter ablation of idiopathic LV VAs. PAM VAs were uncommon, rare in a sustained form, and more common from the posterior papillary muscle (PPM) than anterior papillary muscle (APM). A younger age was a good predictor for differentiating left posterior fascicular VAs from PPM VAs. There were several electrocardiographic features that accurately differentiated PAM and LV fascicular VAs from mitral annular VAs. However, an R/S ratio < or =1 in lead V6 in the LV anterolateral region and a QRS duration >160 ms in the LV posteroseptal region were the only reliable predictors for differentiating PAM VAs from LV fascicular VAs. A sharp ventricular prepotential was recorded at the successful ablation site during 42% of the PAM VAs. Radiofrequency current with an irrigated or conventional 8-mm tip ablation catheter was required to achieve a lasting ablation of the PAM VA origins whereas that with a nonirrigated 4-mm tip ablation catheter produced excellent results in LV fascicular and mitral annular VAs.


CONCLUSIONS
There are differences in the electrocardiographic and electrophysiological features among VAs originating from these regions that are helpful for their diagnosis and effective catheter ablation.
Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama, USA. takumi-y@fb4.so-net.ne.jp
Takumi
T
Yamada
Harish
H
Doppalapudi
Hugh T
HT
McElderry
Taro
T
Okada
Yoshimasa
Y
Murakami
Yasuya
Y
Inden
Yukihiko
Y
Yoshida
Shinji
S
Kaneko
Naoki
N
Yoshida
Toyoaki
T
Murohara
Andrew E
AE
Epstein
Vance J
VJ
Plumb
G Neal
GN
Kay
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000407:Alabama / Q000453:epidemiology; D017115:Catheter Ablation / Q000706:statistics & numerical data*; D015897:Comorbidity; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010210:Papillary Muscles; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery*; D055815:Young Adult