title: [Dual-chamber pacemakers in obstructive hypertrophic cardiomyopathy: gradient variation with stress echocardiography].
abstract: BACKGROUND
  Permanent cardiac pacing with a dual chamber pacemaker has become a valid alternative in treatment of patients with obstructive hypertrophic cardiomyopathy and refractory symptoms to pharmacological treatment, with a significant decrease of left ventricular outflow tract gradient.
  
  
  OBJECTIVE
  To assess any modification of the gradient with dobutamine stress echocardiography.
  
  
  METHODS
  We study 10 patients with obstructive hypertrophic cardiomyopathy and angina and/or dyspnea refractory to customary pharmacological treatment. A dual chamber pacemaker had been implanted 3-6 months previously. A dobutamine stress echocardiography was performed, beginning with a 10 microgram/kg/min infusion, with increases of 10 micrograms each 3 minutes until a maximum of 40. Modification of subaortic gradient, severity of systolic anterior motion of mitral valve (SAM, degree 0-3/3) and severity of mitral regurgitation (degree 0-4/4) were assessed.
  
  
  RESULTS
  Subaortic gradient decreased in all patients after pacemaker implantation (90 +/- 15 vs 20 +/- 10 mmHg; p < 0.001). With stress echocardiography the gradient increased in all patients (20 +/- 10 to 101 +/- 13 mmHg; p < 0.001). After implant there were only two patients with a +1 SAM, while during stress echocardiography SAM developed in all patients in +2 or +3 degree. Three patients had +1 mitral regurgitation after pacemaker implantation but during stress echocardiography 2-4/4 mitral regurgitation developed in all patients.
  
  
  CONCLUSIONS
  Permanent dual chamber pacing decreased left ventricular outflow tract gradient in patients with obstructive hypertrophic cardiomyopathy, but during dobutamine stress echocardiography obstruction echocardiographic signs appeared.
authors.affiliation: Servicio de Cardiología, Hospital General Universitario de Alicante.jgmm@ctv.es
authors.forename: J G
authors.initials: JG
authors.lastname: Martínez Martínez
authors.forename: D
authors.initials: D
authors.lastname: Ortuño Alcaraz
authors.forename: F
authors.initials: F
authors.lastname: Marín Ortuño
authors.forename: J
authors.initials: J
authors.lastname: Luján Martínez
authors.forename: A
authors.initials: A
authors.lastname: Ibáñez Criado
authors.forename: J A
authors.initials: JA
authors.lastname: Quiles Llorens
authors.forename: F
authors.initials: F
authors.lastname: Sogorb Garri
mesh_terms: D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis / Q000628:therapy*; D003627:Data Interpretation, Statistical; D004280:Dobutamine; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D013997:Time Factors
chemical_list: D004280:Dobutamine
vernacular_title: Marcapasos bicameral en la miocardiopatía hipertrófica obstructiva: variación del gradiente con ecocardiografía de estrés.