title: Demonstration of ventricular myocardial extensions into the pulmonary artery and aorta beyond the ventriculo-arterial junction.
abstract: BACKGROUND
  A subgroup of outflow tract (OT) ventricular tachycardias (VT) originate from the aortic sinuses or the main stem of the pulmonary artery. The anatomic substrate for these tachycardias is unknown. The aim of this study was to investigate the presence of ventricular myocardial extensions (VME) into the pulmonary artery (PA) and aorta (Ao) beyond the ventriculo-arterial junction (VAJ) and determine the anatomical and histological characteristics of these muscle extensions.
  
  
  METHODS
  Ninety-five consecutive human hearts obtained at autopsy were studied. Longitudinal strips of tissue containing each cusp, aortic, and pulmonary artery walls and left and right ventricular outflow tracts were excised and histologically analyzed. Anatomical measurements, including length and thickness of VMEs, obtained at autopsy, were made.
  
  
  RESULTS
  VMEs beyond the VAJ were found in 21 of 95 (22%) patients studied. VMEs were found in 16 of 95 PAs (17%) and 7 of 95 Aos (7%) were examined. VMEs were located within the adventitia in 23 (88%) and on the epicardial surface in three (12%). The majority of VMEs were in continuity with the underlying ventricular OT muscle tissue. Myocellular hypertrophy and fibrosis were present in 19 (73%) and fatty tissue between the layers of VME in 18 (69%). Clinical data were available in 14 of 21 patients with positive VME. None of the patients (clinical data available group) had history of cardiac disease or signs or symptoms (palpitations or syncope) of cardiac disease.
  
  
  CONCLUSIONS
  VMEs into the PA and Ao beyond the VAJ are relatively common. It seems that their mere presence does not predispose to OT VTs. There are probably intrinsic arrhythmogenic properties in tissues specific to these regions in those patients who develop OT VTs.
authors: Department of Cardiology, Ege University School of Medicine, Izmir, Turkey. canrfca@yahoo.com
authors: Can
authors: C
authors: Hasdemir
authors: Safiye
authors: S
authors: Aktas
authors: Figen
authors: F
authors: Govsa
authors: Ekin O
authors: EO
authors: Aktas
authors: Aytac
authors: A
authors: Kocak
authors: Yasemin T
authors: YT
authors: Bozkaya
authors: Muge I
authors: MI
authors: Demirbas
authors: Cem
authors: C
authors: Ulucan
authors: Oner
authors: O
authors: Ozdogan
authors: Meral
authors: M
authors: Kayikcioglu
authors: Levent H
authors: LH
authors: Can
authors: Serdar
authors: S
authors: Payzin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000033:anatomy & histology*; D002102:Cadaver; D016009:Chi-Square Distribution; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000033:anatomy & histology*; D017180:Tachycardia, Ventricular / Q000473:pathology