title: Quantitative assessment of cardiac mechanical synchrony using equilibrium radionuclide angiography.
abstract: BACKGROUND
  Data on normal parameters of cardiac mechanical synchrony is limited, variable and obtained from small cohorts till date. In most studies, software used for such assessment has not been mentioned. The aim of study is to establish normal values of mechanical synchrony with equilibrium radionuclide angiography (ERNA) in a larger population using commercially available software.
  
  
  METHODS
  We retrospectively analysed ERNA studies of 108 patients having low pretest likelihood of coronary artery disease, no known history of cardiac disease, normal electrocardiogram and whose ERNA studies were considered normal by experienced observers. In addition, ten patients diagnosed with dilated cardiomyopathy (DCM) and having LVEF ≤ 40% underwent ERNA. Fourier first harmonic analysis of phase images was used to quantify synchrony parameters using commercially available software (XT-ERNA). Intraventricular synchrony for each ventricle was measured as the standard deviation of the LV and RV mean phase angles (SD LVmPA and SD RVmPA, respectively). Interventricular synchrony was measured as LV-RVmPA. Absolute interventricular delay was calculated as absolute difference between LV and RVmPA (without considering ± sign). All variables were expressed in milliseconds (ms) and degree (°). Intra-observer and inter-observer variabilities were assessed. Cut-off values for parameters were calculated from the normal database, and validated against patient group.
  
  
  RESULTS
  On phase analysis, LVmPA was observed to be 343 ± 48.5 milliseconds (174.7° ± 18.5°), SD LVmPA was 16.3 ± 5.4 milliseconds (8.2° ± 2.5°), RVmPA was 339 ± 50.4 milliseconds (171.8° ± 18.5°) and SD RVmPA was 37.3 ± 15.7 milliseconds (18.7° ± 7.2°). LV-RVmPA was observed to be 3.9 ± 21.7 milliseconds (2.9° ± 9.6°) and absolute interventricular delay was 16.3 ± 14.8 milliseconds (7.9° ± 6.1°). The cut-off values for the presence of dyssynchrony were estimated as SD LVmPA > 27.1 milliseconds (>13.2°), SD RVmPA > 68.7 milliseconds (>33.1°) and LV-RVmPA > 47.3 milliseconds (>22.1°). There was no statistically significant intra-observer or inter-observer variability. Using these cut offs, 9 patients with DCM showed the presence of left intraventricular dyssynchrony, 5 had right intraventricular dyssynchrony and 2 had interventricular dyssynchrony.
  
  
  CONCLUSIONS
  ERNA phase analysis offers an objective and reproducible tool to quantify cardiac mechanical synchrony using commercially available software and can be used in routine clinical practice to assess mechanical dyssynchrony.
authors: Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India.
authors: Harmandeep
authors: H
authors: Singh
authors: Abhinav
authors: A
authors: Singhal
authors: Punit
authors: P
authors: Sharma
authors: Chetan D
authors: CD
authors: Patel
authors: Sandeep
authors: S
authors: Seth
authors: Arun
authors: A
authors: Malhotra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D005583:Fourier Analysis; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012984:Software; D013667:Technetium; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000000981:diagnostic imaging*; D055815:Young Adult
chemical_list: D013667:Technetium
references: Arch Med Res. 2010 Feb;41(2):83-91
references: 20470936
references: JAMA. 2003 May 28;289(20):2685-94
references: 12771115
references: J Nucl Cardiol. 2005 Jul-Aug;12(4):441-50
references: 16084433
references: J Am Coll Cardiol. 2003 Dec 17;42(12):2117-24
references: 14680737
references: J Am Coll Cardiol. 2002 Dec 4;40(11):2022-30
references: 12475464
references: J Nucl Med. 1982 Aug;23(8):715-24
references: 7108615
references: Circulation. 2004 Jul 6;110(1):66-73
references: 15197148
references: N Engl J Med. 2005 Apr 14;352(15):1539-49
references: 15753115
references: Circulation. 2008 May 27;117(21):e350-408
references: 18483207
references: Circulation. 2011 Feb 1;123(4):e18-e209
references: 21160056
references: Circulation. 2002 Oct 1;106(14):1760-3
references: 12356626
references: J Nucl Cardiol. 2005 Nov-Dec;12(6):687-95
references: 16344231
references: Circulation. 2008 May 20;117(20):2608-16
references: 18458170
references: J Am Coll Cardiol. 2000 Apr;35(5):1221-7
references: 10758964
references: J Nucl Cardiol. 2008 Jan-Feb;15(1):127-36
references: 18242490
references: Pacing Clin Electrophysiol. 2003 Sep;26(9):1815-23
references: 12930495
references: Pacing Clin Electrophysiol. 2007 Jan;30 Suppl 1:S58-61
references: 17302719
references: J Nucl Cardiol. 2003 Jul-Aug;10(4):424-8
references: 12900747
references: J Nucl Cardiol. 2011 Feb;18(1):36-42
references: 21104361
references: Am J Cardiol. 2007 Dec 1;100(11):1665-70
references: 18036366
references: J Am Coll Cardiol. 2004 Nov 2;44(9):1834-40
references: 15519016
references: N Engl J Med. 2002 Nov 28;347(22):1803-4; author reply 1803-4
references: 12456861
references: JACC Cardiovasc Imaging. 2008 Sep;1(5):605-13
references: 19356489
references: Circulation. 1982 Mar;65(3):551-60
references: 7055877
references: Nucl Med Commun. 2006 Feb;27(2):105-12
references: 16404222
references: J Am Coll Cardiol. 1984 Mar;3(3):799-814
references: 6693651
references: J Am Coll Cardiol. 1995 Nov 15;26(6):1476-83
references: 7594073
references: Am J Cardiol. 2003 Aug 1;92(3):341-4
references: 12888151
references: Am J Cardiol. 1971 Nov;28(5):575-80
references: 5116974
references: J Am Coll Cardiol. 2002 Nov 6;40(9):1615-22
references: 12427414
references: Eur J Nucl Med Mol Imaging. 2008 May;35(5):912-21
references: 18228016
references: J Nucl Cardiol. 2008 Jan-Feb;15(1):10-2
references: 18242474
references: N Engl J Med. 2001 Mar 22;344(12):873-80
references: 11259720
references: N Engl J Med. 2004 May 20;350(21):2140-50
references: 15152059
references: Am J Cardiol. 1991 Jan 15;67(2):148-56
references: 1987716
references: Heart Rhythm. 2005 Sep;2(9):960-5
references: 16171751
references: Eur J Heart Fail. 2007 May;9(5):484-90
references: 17347038
references: N Engl J Med. 2002 Jun 13;346(24):1845-53
references: 12063368
references: Am J Cardiol. 1985 Feb 15;55(5):535-40
references: 3969896
references: J Cardiovasc Magn Reson. 2008 Nov 04;10:49
references: 18983646