title: Association between left ventricular regional sympathetic denervation and mechanical dyssynchrony in phase analysis: a cardiac CZT study.
abstract: OBJECTIVE
  To evaluate the relationships among myocardial sympathetic innervation, perfusion and mechanical synchronicity assessed with cardiac cadmium-zinc-telluride (CZT) scintigraphy.
  
  
  METHODS
  A group of 29 patients underwent an evaluation of myocardial perfusion with (99m)Tc-tetrofosmin CZT scintigraphy and adrenergic innervation with (123)I-metaiodobenzylguanidine (MIBG) CZT scintigraphy. The summed rest score (SRS), motion score (SMS) and thickening score (STS), as well as the summed (123)I-MIBG defect score (SS-MIBG), were determined. Regional tracer uptake for both (99m)Tc-tetrofosmin and (123)I-MIBG was also calculated. Finally, the presence of significant myocardial mechanical dyssynchrony was evaluated in phase analysis on gated CZT images and the region of latest mechanical activation identified.
  
  
  RESULTS
  Significant mechanical dyssynchrony was present in 17 patients (59 %) and associated with higher SRS (P = 0.030), SMS (P < 0.001), STS (P = 0.003) and early SS-MIBG (P = 0.037) as well as greater impairments in left ventricular ejection fraction (P < 0.001) and end-diastolic volume (P < 0.001). In multivariate analysis a higher end-diastolic volume remained the only predictor of mechanical dyssynchrony (P = 0.047). Interestingly, while in the whole population regional myocardial perfusion and adrenergic activity were strongly correlated (R = 0.68), in patients with mechanical dyssynchrony the region of latest mechanical activation was predicted only by greater impairment in regional (123)I-MIBG uptake (P = 0.012) that overwhelmed the effect of depressed regional perfusion.
  
  
  CONCLUSIONS
  Left ventricular mechanical dyssynchrony is associated with greater depression in contractile function and greater impairments in regional myocardial perfusion and sympathetic activity. In patients with dyssynchrony, the region of latest mechanical activation is characterized by a significantly altered adrenergic tone.
authors: Fondazione Toscana Gabriele Monasterio, Via Moruzzi, 1, 56124, Pisa, Italy, gimelli@ftgm.it.
authors: Alessia
authors: A
authors: Gimelli
authors: Riccardo
authors: R
authors: Liga
authors: Dario
authors: D
authors: Genovesi
authors: Assuero
authors: A
authors: Giorgetti
authors: Annette
authors: A
authors: Kusch
authors: Paolo
authors: P
authors: Marzullo
mesh_terms: D019797:3-Iodobenzylguanidine / Q000494:pharmacology; D000368:Aged; D002104:Cadmium; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; D005260:Female; D015902:Gamma Cameras; D006352:Heart Ventricles / Q000294:innervation* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D055414:Myocardial Perfusion Imaging; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D013318:Stroke Volume; D017779:Sympathetic Fibers, Postganglionic / Q000187:drug effects / Q000503:physiopathology; D013691:Tellurium; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*; D015032:Zinc
chemical_list: C474490:CdZnTe; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D002104:Cadmium; D019797:3-Iodobenzylguanidine; C078700:technetium tc-99m tetrofosmin; D015032:Zinc; D013691:Tellurium