title: Time to significant gradient reduction following septal balloon occlusion predicts the magnitude of final gradient response during alcohol septal ablation in patients with hypertrophic obstructive cardiomyopathy.
abstract: OBJECTIVE
  The purpose of this study was to investigate whether a relationship exists between an acute reduction in resting left ventricular outflow tract (LVOT) gradient with balloon occlusion and the final invasive gradient response following alcohol septal ablation (ASA).
  
  
  BACKGROUND
  ASA is an alternative therapy to myectomy surgery to reduce the basal septal thickness and decrease the resting and/or provocable LVOT gradient in patients with hypertrophic cardiomyopathy. Patients have a variable gradient response to occlusion of the septal perforator artery before ethanol infusion for ASA.
  
  
  METHODS
  From November 1998 to November 2008, 120 patients (mean age 60 years [range 16 to 87 years], 50% women) with hypertrophic cardiomyopathy underwent ASA at our institution. The resting LVOT gradient (peak systolic left ventricle [LV] pressure - peak systolic aortic pressure) was measured continuously during the ASA procedure. The time to significant LVOT gradient decrease (defined as >50% decrease from baseline) was recorded following balloon occlusion of the dominant septal perforator coronary artery, which was found to perfuse the basal septum based on contrast echocardiographic studies.
  
  
  RESULTS
  The mean baseline resting LVOT gradient was 86 ± 43 mm Hg, and it decreased to 17 ± 11 mm Hg following ASA (-80.2%). The mean time to significant gradient reduction was 3.6 ± 2 min (range 25 s to 11 min). The time to significant LVOT gradient reduction strongly correlated with the final magnitude of gradient reduction following ASA (r = -0.81, p < 0.001).
  
  
  CONCLUSIONS
  This study demonstrates a correlation between the time to significant LVOT gradient reduction following septal perforator balloon occlusion and the magnitude of final gradient response after ASA.
authors.affiliation: Division of Cardiology, Department of Medicine, Peter Munk Cardiac Centre, University Health Network, Toronto, Ontario, Canada.
authors.forename: Ali
authors.initials: A
authors.lastname: Almasood
authors.forename: Patrick
authors.initials: P
authors.lastname: Garceau
authors.forename: Anna
authors.initials: A
authors.lastname: Woo
authors.forename: Harry
authors.initials: H
authors.lastname: Rakowski
authors.forename: Leonard
authors.initials: L
authors.lastname: Schwartz
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Overgaard
mesh_terms: D055011:Ablation Techniques; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001011:Aorta / Q000503:physiopathology; D021721:Balloon Occlusion; D001794:Blood Pressure; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D000431:Ethanol / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009864:Ontario; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D014694:Ventricular Outflow Obstruction / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D017725:Ventricular Pressure; D055815:Young Adult
chemical_list: D000431:Ethanol