title: Fourier phase analysis on equilibrium gated radionuclide ventriculography: Range of phase spread and cut-off limits in normal individuals.
abstract: OBJECTIVE
  To define the range of phase spread on equilibrium gated radionuclide ventriculography (ERNV) in normal individuals and derive the cut-off limit for the parameters to detect cardiac dyssynchrony.
  
  
  METHODS
  ERNV was carried out in 30 individuals (age 53±23 years, 25 males and 5 females) who had no history of cardiovascular disease. They all had normal left ventricular ejection fraction (LVEF 55-70%) as determined by echocardiography, were in sinus rhythm, with normal QRS duration (≤120 msec) and normal coronary angiography. First harmonic phase analysis was performed on scintigraphic data acquired in best septal view. Left and right ventricular standard deviation (LVSD and RVSD, respectively) and interventricular mechanical delay (IVMD), the absolute difference of mean phase angles of right and left ventricle, were computed and expressed in milliseconds. Mean + 3 standard deviation (SD) was used to derive the cut-off limits.
  
  
  RESULTS
  Average LVEF and duration of cardiac cycle in the study group were 62.5%±5.44% and 868.9±114.5 msec, respectively. The observations of LVSD, RVSD and right and left ventricular mean phase angles were shown to be normally distributed by Shapiro-Wilk test. Cut-off limits for LVSD, RVSD and IVMD were calculated to be 80 msec, 85 msec and 75 msec, respectively.
  
  
  CONCLUSIONS
  Fourier phase analysis on ERNV is an effective tool for the evaluation of synchronicity of cardiac contraction. The cut-off limits of parameters of dyssynchrony can be used to separate heart failure patients with cardiac dyssynchrony from those without. ERNV can be used to select patients for cardiac resynchronization therapy.
authors: Department of Nuclear Medicine and Department of Cardiology, Narayana Hrudayalaya Institute of Medical Sciences, Bengaluru, Karnataka, India.
authors: Vijayaraghavan L
authors: VL
authors: Ramaiah
authors: B
authors: B
authors: Harish
authors: Hv
authors: H
authors: Sunil
authors: Job
authors: J
authors: Selvakumar
authors: Kishore Ag
authors: KA
authors: Ravi
authors: Gopinathan
authors: G
authors: Nair
keywords: Cardiac dyssynchrony; equilibrium gated radionuclide ventriculography; interventricular mechanical delay; left ventricular ejection fraction; left ventricular standard deviation; right ventricular standard deviation