title: Anatomical correlates relevant to ablation above the semilunar valves for the cardiac electrophysiologist: a study of 603 hearts.
abstract: BACKGROUND
  Certain outflow tract tachyarrhythmias require ablation above the semilunar valves. Understanding of the regional anatomy of these arrhythmogenic sites is required to avoid complications.
  
  
  RESULTS
  We examined 603 formalin-fixed autopsy hearts from October 1998 to July 2003. Three hundred forty-two of 603 (57%) had myocardial extensions above the aortic valve, and 446 of 602 (74%) had extensions above the pulmonary valve. Extensions were noted above the aortic right coronary cusp (RCC) in 332 of 603 (55%; 2.8 ± 1.2 mm), left coronary cusp (LCC) in 145 of 603 (24%; 1.5 ± 0.5 mm), and non-coronary/posterior cusp in four of 603 (0.66%; 1.3 ± 0.5 mm; p < 0.0001), intercuspally in 295 of 603 (49%; 2.2 ± 1.1 mm) and into the cusps in 13 of 603 (2.2%). Extensions were noted above the pulmonary right cusp in 360 of 602 (60%; 4.0 ± 2.5 mm), posterior/left cusp in 313 of 602 (52%; 3.6 ± 2.1 mm), and anterior cusp in 268 of 602 (45%; 3.7 ± 2.2 mm; p < 0.0001), intercuspally in 438 of 602 (73%; 3.4 ± 1.8 mm) and into the cusps in ten of 602 (1.7%). The left main coronary artery was closer to the myocardial extensions above the nearest pulmonary valve cusp (posterior) than those above the nearest aortic valve cusp (LCC; 4.8 ± 1.7 vs. 16.3 ± 3.3 mm, p = 0.0005).
  
  
  CONCLUSIONS
  Myocardial extensions are common into the great arteries above the semilunar cusps and intercuspally, and rarely into the cusps themselves. The extensions are larger and more symmetric above the pulmonary cusps as compared to the aortic cusps, the most prominent aortic extensions being above the RCC. The left main coronary artery courses close to the extensions above the posterior pulmonary cusp.
authors.affiliation: Midwest Heart Specialists, Elmhurst, IL, USA.
authors.forename: Apoor S
authors.initials: AS
authors.lastname: Gami
authors.forename: Amit
authors.initials: A
authors.lastname: Noheria
authors.forename: Nirusha
authors.initials: N
authors.lastname: Lachman
authors.forename: William D
authors.initials: WD
authors.lastname: Edwards
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
authors.forename: Deepak
authors.initials: D
authors.lastname: Talreja
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Hammill
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Munger
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Packer
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000033:anatomy & histology*; D002102:Cadaver; D006348:Cardiac Surgical Procedures; D002648:Child; D002675:Child, Preschool; D022062:Electrophysiologic Techniques, Cardiac; D006329:Heart Conduction System / Q000033:anatomy & histology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D011664:Pulmonary Valve / Q000033:anatomy & histology*; D055815:Young Adult