title: Nonreentrant ventricular arrhythmias in patients with structural heart disease unrelated to abnormal myocardial substrate.
abstract: BACKGROUND
  Ventricular arrhythmias in the absence of structural heart disease are commonly referred to as "idiopathic." Patients with structural heart disease have ventricular arrhythmias with the same mechanisms and sites of origin as idiopathic ventricular arrhythmias, but the prevalence of such arrhythmias is not well defined.
  
  
  OBJECTIVE
  To identify the prevalence of nonreentrant ventricular arrhythmias unrelated to abnormal myocardial substrate in patients with structural heart disease and to compare these arrhythmias to ventricular arrhythmias in patients with structurally normal hearts.
  
  
  METHODS
  Of 249 consecutive patients referred for ablation of ventricular arrhythmias, 97 (39%) patients had nonreentrant arrhythmias unrelated to underlying structural heart disease. Fifty-five (57%) patients had structurally normal hearts, and 42 (43%) had underlying structural heart disease.
  
  
  RESULTS
  Compared with patients with structurally normal hearts, patients with structural heart disease were more likely to have nonreentrant ventricular arrhythmias unrelated to underlying abnormal myocardial substrate originating from the aortic cusps and left ventricular outflow tract whereas patients without structural heart disease more often had arrhythmias originating from the right ventricular outflow tract. There was a significant increase in the average left ventricular ejection fraction after ablation in patients with structural heart disease.
  
  
  CONCLUSIONS
  Nonreentrant ventricular arrhythmias unrelated to abnormal myocardial substrate are common in patients with structural heart disease, and sites of origin differ from those seen in patients with structurally normal hearts. When managing structural heart disease in patients with ventricular arrhythmias, a focus on arrhythmia mechanism, origin, and relationship to underlying myocardial substrate may have important implications for future treatment options and patient outcomes.
authors.affiliation: Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts. Electronic address: eellis@bidmc.harvard.edu.
authors.forename: Ethan R
authors.initials: ER
authors.lastname: Ellis
authors.affiliation: Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Alexei
authors.initials: A
authors.lastname: Shvilkin
authors.affiliation: Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Josephson
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000503:physiopathology* / Q000628:therapy; D017115:Catheter Ablation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D012189:Retrospective Studies; D013318:Stroke Volume; D016277:Ventricular Function, Left
keywords: Cardiomyopathy; Coronary artery disease; Idiopathic ventricular tachycardia; Left ventricular dysfunction; Myocardial infarction; Outflow tract tachycardia; Premature ventricular contractions; Structural heart disease; Tachycardia-mediated cardiomyopathy