title: Utility of isoproterenol to provoke outflow tract gradients in patients with hypertrophic cardiomyopathy.
abstract: It is important to identify patients with hypertrophic cardiomyopathy (HC) who have labile left ventricular outflow tract (LVOT) obstruction for consideration of ventricular septal reduction therapy. Although Doppler echocardiography has become the diagnostic modality to assess LVOT obstruction, it may not identify all patients with labile obstruction. This study assessed the diagnostic value of cardiac catheterization using isoproterenol challenge in 25 patients with HC in whom an LVOT obstruction (gradient >or=50 mm Hg) was clinically suspected, but not diagnosed using Doppler echocardiography. These patients underwent cardiac catheterization using a transseptal approach with isoproterenol challenge. During isoproterenol infusion, the gradient increased to >or=50 mm Hg in 14 patients and remained <50 mm Hg in 11 patients. Ten patients subsequently underwent surgical myectomy, 6 patients underwent alcohol septal ablation, and 9 patients were managed medically. Median follow-up was 26 months. Of patients who had a provoked gradient >50 mm Hg during isoproterenol infusion, 8 patients who underwent septal myectomy and 5 of 6 patients who underwent alcohol septal ablation had sustained alleviation of symptoms at follow-up. In conclusion, cardiac catheterization with isoproterenol challenge may identify patients with HC who may benefit from septal reduction therapy for whom the initial noninvasive evaluation does not show severe obstruction.
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Elesber
authors.forename: Rick A
authors.initials: RA
authors.lastname: Nishimura
authors.forename: Charanjit S
authors.initials: CS
authors.lastname: Rihal
authors.forename: Steve R
authors.initials: SR
authors.lastname: Ommen
authors.forename: Hartzell V
authors.initials: HV
authors.lastname: Schaff
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D002121:Calcium Channel Blockers / Q000627:therapeutic use; D006328:Cardiac Catheterization; D006348:Cardiac Surgical Procedures; D002312:Cardiomyopathy, Hypertrophic / Q000628:therapy*; D002316:Cardiotonic Agents; D004206:Disopyramide / Q000627:therapeutic use; D000431:Ethanol / Q000008:administration & dosage; D005260:Female; D006346:Heart Septum / Q000601:surgery; D006801:Humans; D007545:Isoproterenol; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012997:Solvents / Q000008:administration & dosage; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis* / Q000628:therapy
chemical_list: D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D002121:Calcium Channel Blockers; D002316:Cardiotonic Agents; D012997:Solvents; D000431:Ethanol; D004206:Disopyramide; D007545:Isoproterenol