title: Cardiac resynchronization therapy restored ventricular septal myocardial perfusion and enhanced ventricular remodeling in patients with nonischemic cardiomyopathy presenting with left bundle branch block.
abstract: BACKGROUND
  Left bundle branch block (LBBB) causes intraventricular conductional delay, which results in left ventricle (LV) mechanical dyssynchrony. In the absence of coronary artery disease, patients with LBBB often have diminished accumulation of technetium-99m compounds at the myocardial septal area in electrocardiogram-gated single-photon emission computed tomography.
  
  
  OBJECTIVE
  To investigate whether cardiac resynchronization therapy (CRT) could improve septal myocardial perfusion, leading to favorable reverse remodeling.
  
  
  METHODS
  The study included all 26 patients with nonischemic cardiomyopathy eligible for CRT, who presented with LBBB, New York Heart Association class II-IV heart failure, and LV ejection fraction ≤35%. Single-photon emission computed tomography was performed at baseline and 6 months after CRT. Perfusion counts were measured at the ventricular septum and LV lateral free wall. Left ventricular end-systolic volume (LVESV) was measured by echocardiography to evaluate LV reverse remodeling by CRT.
  
  
  RESULTS
  At baseline, a perfusion defect at the LV septal myocardial area was confirmed in 19 of 26 (73%) patients. In these patients, septal perfusion significantly increased 6 months after CRT (56.1% ± 22.8% vs 82.9% ± 21.2%; P < .001). LVESV reduction and improved septal perfusion index were positively correlated (r = .561; P = .012), whereas no correlation was found between LVESV reduction and the difference of QRS duration before and 6 months after CRT (r = .218; P = .371). The improvement in LV septal perfusion was associated with LV reverse remodeling.
  
  
  CONCLUSIONS
  CRT could restore LV septal myocardial perfusion and ameliorate ventricular reverse remodeling in most patients with nonischemic cardiomyopathy and LBBB.
authors.affiliation: Department of Cardiovascular Medicine, Shizuoka Medical Center, Shizuoka, Japan. Electronic address: m-ogano@nms.ac.jp.
authors.forename: Michio
authors.initials: M
authors.lastname: Ogano
authors.affiliation: Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Yu-Ki
authors.initials: YK
authors.lastname: Iwasaki
authors.affiliation: Department of Cardiovascular Medicine, Shizuoka Medical Center, Shizuoka, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Tanabe
authors.affiliation: Department of Cardiovascular Surgery, Shizuoka Medical Center, Shizuoka, Japan.
authors.forename: Hisato
authors.initials: H
authors.lastname: Takagi
authors.affiliation: Department of Cardiovascular Surgery, Shizuoka Medical Center, Shizuoka, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Umemoto
authors.affiliation: Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Meiso
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyauchi
authors.affiliation: Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Shimizu
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D009202:Cardiomyopathies / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D013318:Stroke Volume; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling / Q000502:physiology*; D054088:Ventricular Septum / Q000000981:diagnostic imaging / Q000503:physiopathology*
keywords: Cardiac resynchronization therapy; Emission computed tomography; Heart failure; Left bundle branch block; Redistribution