title: Ventricular tachycardia originating from the posterior papillary muscle in the left ventricle: a distinct clinical syndrome.
abstract: BACKGROUND
  Several distinct forms of focal ventricular tachycardia (VT) from the left ventricle (LV) have been described. We report a new syndrome of VT arising from the base of the posterior papillary muscle in the LV.
  
  
  RESULTS
  Among 290 consecutive patients who underwent ablation for VT or symptomatic premature ventricular complexes (PVCs) based on a focal mechanism, 7 patients were found to have an ablation site at the base of the posterior papillary muscle in the LV. All patients had normal LV systolic function and a normal baseline electrocardiogram. The electrocardiogram during VT or PVCs demonstrated a right bundle-branch block and superior-axis QRS morphology in all patients. VT was not inducible by programmed atrial or ventricular stimulation. In 2 patients with sustained VT, overdrive pacing neither terminated VT nor demonstrated any criterion for transient entrainment. Activation mapping localized the earliest site of activation to the base of the posterior papillary muscle in all patients. When Purkinje potentials were recorded at the site of successful ablation, these potentials preceded local ventricular muscle potentials during sinus rhythm. During VT or PVCs, however, the ventricular muscle potential always preceded the Purkinje potentials. After recurrence of VT or PVCs with standard radiofrequency ablation, irrigated ablation was successful in eliminating the arrhythmia in all patients. Over a mean follow-up period of 9 months, all patients have been free of PVCs and VT.
  
  
  CONCLUSIONS
  We present a distinct syndrome of VT arising from the base of the posterior papillary muscle in the LV by a nonreentrant mechanism. Ablation can be challenging, and irrigated ablation may be necessary for long-term success.
authors.affiliation: Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors.forename: Harish
authors.initials: H
authors.lastname: Doppalapudi
authors.forename: Takumi
authors.initials: T
authors.lastname: Yamada
authors.forename: H Thomas
authors.initials: HT
authors.lastname: McElderry
authors.forename: Vance J
authors.initials: VJ
authors.lastname: Plumb
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Epstein
authors.forename: G Neal
authors.initials: GN
authors.lastname: Kay
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002037:Bundle-Branch Block / Q000209:etiology / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation / Q000379:methods; D003937:Diagnosis, Differential; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D015444:Exercise; D005260:Female; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010210:Papillary Muscles / Q000503:physiopathology*; D011690:Purkinje Fibers / Q000503:physiopathology; D012008:Recurrence; D012086:Reoperation; D013577:Syndrome; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D007507:Therapeutic Irrigation; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery