title: Prediction of left ventricular wall motion recovery after acute myocardial infarction by Tl-201 gated SPECT: incremental value of integrated contractile reserve assessment.
abstract: BACKGROUND
  This investigation tested the application of low-dose dobutamine (LDD) gated single photon emission computed tomography (SPECT) with thallium 201 for myocardial viability detection early after acute myocardial infarction (AMI).
  
  
  RESULTS
  Thirty-two hemodynamically stable post-AMI patients (aged 55 +/- 5 years [mean +/- SEM]; 20 men) who were exhibiting regional left ventricular dysfunction underwent stress-redistribution Tl-201 scanning within 4 to 8 days, followed by 2 additional gated SPECT acquisitions after Tl-201 reinjection, at rest and during LDD. A visual 5-point score was computed for segmental radiotracer uptake (0, normal; 4, absent) and a 4-point score for left ventricular wall motion (1, normal; 4, dyskinesis). Predominant viable myocardium in dyssynergic regions was predicted by a mean Tl-201 uptake score of 2 or less or ischemic area of 30% or greater. These indices showed a significant association with wall motion improvement in follow-up echocardiographic studies (overall accuracy = 0.69, sensitivity = 0.93, and specificity = 0.50). Regarding the response to LDD stimulus, an increase in mean wall motion score of 30% or greater was predictive of predominant viable myocardium. Contractile reserve assessment yielded a significant increment in the predictive accuracy for function recovery (overall accuracy = 0.84, sensitivity = 0.71, and specificity = 0.94).
  
  
  CONCLUSIONS
  Evaluation of contractile reserve by means of LDD gated SPECT with Tl-201 is safely feasible early after AMI, with incremental value over perfusion assessment alone for myocardial viability detection.
authors.affiliation: Division of Cardiology, Medical School of Ribeirão Preto, Ribeirão Preto Campus, University of São Paulo, CEP: 14048-900 Ribeirão Preto, São Paulo, Brazil.
authors.forename: Marcus Vinicius
authors.initials: MV
authors.lastname: Simões
authors.forename: Oswaldo César
authors.initials: OC
authors.lastname: de Almeida-Filho
authors.forename: Antonio Osvaldo
authors.initials: AO
authors.lastname: Pintya
authors.forename: Alexandre Baldini
authors.initials: AB
authors.lastname: de Figueiredo
authors.forename: Cleide Marques
authors.initials: CM
authors.lastname: Antloga
authors.forename: Fernando Vilela
authors.initials: FV
authors.lastname: Salis
authors.forename: Nadia de Paula
authors.initials: Nde P
authors.lastname: Batista
authors.forename: Moysés de Oliveira
authors.initials: Mde O
authors.lastname: Lima-Filho
authors.forename: Benedito Carlos
authors.initials: BC
authors.lastname: Maciel
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Marin-Neto
mesh_terms: D004280:Dobutamine; D004452:Echocardiography; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D013794:Thallium Radioisotopes; D004280:Dobutamine