Idiopathic focal ventricular arrhythmias originating from the anterior papillary muscle in the left ventricle.
BACKGROUND
Focal ventricular arrhythmias (VAs) have been reported to arise from the posterior papillary muscle in the left ventricle (LV). We report a distinct subgroup of idiopathic VAs arising from the anterior papillary muscle (APM) in the LV.


RESULTS
We studied 432 consecutive patients undergoing catheter ablation for VAs based on a focal mechanism. Six patients were identified with ventricular tachycardia (VT, n = 1) or premature ventricular contractions (PVCs, n = 5) with the earliest site of ventricular activation localized to the base (n = 3) or middle portion (n = 3) of the LV APM. No Purkinje potentials were recorded at the ablation site during sinus rhythm or the VAs. All patients had a normal baseline electrocardiogram and normal LV systolic function. The VAs exhibited a right bundle branch block (RBBB) and right inferior axis (RIA) QRS morphology in all patients. Oral verapamil and/or Na(+) channel blockers failed to control the VAs in 4 patients. VT was not inducible by programmed electrical stimulation in any of the patients. In 4 patients, radiofrequency current with an irrigated or conventional 8-mm-tip ablation catheter was required to achieve a lasting success. Two patients had recurrent PVCs after a conventional radiofrequency ablation with a 4-mm-tip ablation catheter had initially suppressed the arrhythmia.


CONCLUSIONS
VAs may arise from the base or middle portion of the APM and are characterized by an RBBB and RIA QRS morphology and focal mechanism. Catheter ablation of APM VAs is typically challenging, and creation of a deep radiofrequency lesion may be necessary for long-term success.
Yamada
Takumi
T
Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA. takumi-y@fb4.so-net.ne.jp
McElderry
H Thomas
HT
Okada
Taro
T
Murakami
Yoshimasa
Y
Doppalapudi
Harish
H
Yoshida
Naoki
N
Allred
James D
JD
Murohara
Toyoaki
T
Kay
G Neal
GN
D000328:Adult; D000368:Aged; D017115:Catheter Ablation / Q000379:methods; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010210:Papillary Muscles / Q000503:physiopathology* / Q000601:surgery; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000601:surgery