title: [Left ventricular dyssynchrony in prolonged septal stimulation].
abstract: Pacemaker stimulation is associated with unpredictable severe cardiac events. We evaluated left ventricular mechanical dyssynchrony (LVMD) during prolonged septal right ventricular pacing. We performed 99mTc-MIBI gated-SPECT and phase analysis in 6 patients with pacemakers implanted at least one year before scintigraphy due to advanced atrioventricular block. Using V-Sync of Emory Cardiac Toolbox we obtained phase bandwidth (PBW) and standard deviation (PSD) from rest phase histogram. Clinical variables, QRS duration, rate and mode of pacing in septal right ventricle wall, chamber diameters, presence and extension of myocardial scar and ischemia and rest LVEF were recorded. Prolonged septal endocardial pacing is associated with marked LVMD, even when systolic function was preserved. More severe dyssynchrony was found in patients with impaired LVEF, higher left ventricle diameters, extensive infarct or severe ischemia than in patients with preserved LVEF (PBW: 177.3o vs. 88.3o; PSD: 53.1o vs. 33.8o). In the patients with ischemic heart disease and pacemaker, gated-SPECT phase analysis is a valid and potentially useful technique to evaluate LMVD associated with myocardial scar and to decide the upgrading to biventricular pacing mode.
authors.affiliation: 1Departamento de Cardiología, Centro Cardiovascular Universitario, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay, E-mail: federico.ferrando@gmail.com.
authors.forename: Federico
authors.initials: F
authors.lastname: Ferrando-Castagnetto
authors.affiliation: 1Departamento de Cardiología, Centro Cardiovascular Universitario, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: Roberto
authors.initials: R
authors.lastname: Ricca-Mallada
authors.affiliation: Departamento de Cardiología, Centro Cardiovascular Universitario, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Vidal
authors.affiliation: Departamento de Cardiología, Centro Cardiovascular Universitario, Hospital de Clínicas, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors.forename: Fabián
authors.initials: F
authors.lastname: Martínez
authors.affiliation: Servicio de Medicina Nuclear, Centro Asistencial del Sindicato Médico, Montevideo, Uruguay.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Ferrando
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000601:surgery; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000209:etiology; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D012720:Severity of Illness Index; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology*; D054088:Ventricular Septum / Q000000981:diagnostic imaging / Q000503:physiopathology*
keywords: dyssynchrony; myocardial infarct; pacemaker