title: Incidence and predictors of late complete heart block after alcohol septal ablation treatment of hypertrophic obstructive cardiomyopathy.
abstract: OBJECTIVE
  This study was designed to identify the incidence of late complete heart block (CHB) first identified at least 48 hours post alcohol septal ablation (ASA).
  
  
  BACKGROUND
  Septal reduction with ASA is a therapeutic option for patients with symptomatic hypertrophic obstructive cardiomyopathy (HCM). CHB, resulting from the septal infarct, is a known complication with a reported incidence of 9-22%. The incidence of CHB more than 48 hours post-procedure is unknown.
  
  
  METHODS
  Consecutive patients who underwent ASA were analyzed and clinical characteristics associated with late CHB were assessed. Late CHB was defined as first identification of CHB more than 48 hours after ASA.
  
  
  RESULTS
  From 2002-2013, 145 subjects underwent 168 ASA procedures and were followed for a mean of 3.2 +/- 2.3 years. The incidence of late CHB was 8.9% (15/168 ASA procedures). Heart block occurred from 48 hours to 3-years post-procedure. In a multivariable model, patients with any CHB were more likely to have had multiple ASA procedures (OR 4.14; 95% CI: 1.24, 13.9; P < 0.05) and high resting and provoked left ventricular outflow tract (LVOT) gradient assessed by catheterization (OR per 10 mmHg gradient 1.14; 95% CI: 1.0, 1.20; P < 0.05). After multivariable adjustment, only a high provokable LVOT gradient remained an independent predictor of late CHB (OR per 10 mmHg gradient 1.14 [95% CI 1.02-1.29]).
  
  
  CONCLUSIONS
  Late CHB is a common complication of ASA for treatment of symptomatic HCM. Post-discharge electrocardiographic surveillance for atrioventricular conduction disease should be considered after ASA, especially for those with a high provokable LVOT gradient.
authors.affiliation: Cardiology Division, Denver Health, Denver, Colorado; University of Colorado School of Medicine, Aurora, Colorado.
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Schuller
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Zipse
authors.forename: Mori J
authors.initials: MJ
authors.lastname: Krantz
authors.forename: Brian
authors.initials: B
authors.lastname: Blaker
authors.forename: Ernesto
authors.initials: E
authors.lastname: Salcedo
authors.forename: Bertron M
authors.initials: BM
authors.lastname: Groves
authors.forename: John C
authors.initials: JC
authors.lastname: Messenger
authors.forename: Brenda
authors.initials: B
authors.lastname: Beaty
authors.forename: William H
authors.initials: WH
authors.lastname: Sauer
mesh_terms: D055011:Ablation Techniques / Q000009:adverse effects*; D002312:Cardiomyopathy, Hypertrophic / Q000601:surgery*; D000431:Ethanol / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000209:etiology*; D006346:Heart Septum / Q000601:surgery*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D019233:Retreatment / Q000706:statistics & numerical data; D014694:Ventricular Outflow Obstruction / Q000150:complications
chemical_list: D000431:Ethanol