[Short exercise-rest versus long myocardial perfusion gated SPECT protocols in patients with ischemic cardiomyopathy].
OBJECTIVE
The purpose of this study was to analyze left systolic ventricular function and myocardial perfusion characteristics between short one day exercise-rest and long two days gated SPECT (Single Photon Emission Computed Tomography) protocols in patients with ischemic cardiomyopathy (ICM).


METHODS
A prospective study of 40 patients (59.6±8.9 years, 3 women) with IHD (left ventricular ejection fraction (EF) ≤40%) was performed with myocardial perfusion gated SPECT. From 5 to 10 days after a one-day exercise-rest study (gated SPECT-1), patients were called back for a second rest study (gated SPECT-2) in order to compare EF and differences in perfusion summed rest score (ΔSRS=SRS1-SRS2) and summed difference score (ΔSDS=SDS1-SDS2) between both protocols.


RESULTS
Between rest-gated SPECT-1 (short protocol) and rest-gated SPECT-2 (long protocol) EF increased (34% vs 37%, P= 0.008) in 26 patients (65%), and in 11 patients (27.5%) the increase was ≥5%. There were no significant differences in clinical and coronary angiography variables between patients with and without increase of the EF ≥5%. In the multivariate analysis, ΔSRS (95% CI: -1.1 to -29.2) and ΔSDS (0.179-1.236) were predictors for this EF increase between both studies.


CONCLUSIONS
Exercise-rest short protocol can underestimate EF in patients with CM. Stunning but also contamination of rest images by previous exercise images in a short protocol could explain these results.
Candell-Riera
J
J
Servicio de Cardiología, Àrea del Cor, Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona, España. jcandell@vhebron.net
Romero-Farina
G
G
Aguadé-Bruix
S
S
Castell-Conesa
J
J
Aliaga
V
V
Cuberas-Borrós
G
G
García-Dorado
D
D
D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; D002985:Clinical Protocols; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D013997:Time Factors; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging