IJCS | Volume 31, Nº3, May/ June 2018

267 Wiefels et al. Evaluation of Desynchronization with GSPECT in Patients with Heart Failure International Journal of Cardiovascular Sciences. 2018;31(3)264-273 Original Article association between QRS duration and the presence of dyssynchrony. Figure 1 analyzes QRS duration with the SD values of the phase histogram. It was known that the higher the SD (SD > 43°), the higher the intraventricular dyssynchrony. Likewise, a QRS > 130 ms was associated with a higher probability of dyssynchrony. The association of both parameters was directly proportional. When analyzed with HBW, it was also observed that the longer the QRS duration, the greater its value. This demonstrates that HBW and SD were also directly associated, as both increased with QRS enlargement and the presence of dyssynchrony. SD and HBW values were higher for responders than for non-responders, and the difference between HBW in both groups was statistically significant (Figure 2). Discussion The present study evaluated dyssynchrony at pre and post-implantation of CRT through GSPECT. CRT had a positive impacted on functional capacity, MD and ED of patients with advanced HF and LBBB and demonstrated the use of GSPECT to identify patients with a higher probability of responding to CRT. GSPECT is a useful tool for assessing systolic function in patients submitted to perfusion studies by adding diagnostic and prognostic informationwithout additional exposure to radiation. 15 Technological evolution has allowed phase analysis to be employed in GSPECT studies, providing significant data regarding ventricular synchrony. 13 Trimble et al. 16 used the technique of phase analysis in myocardial perfusion scintigraphy, comparing patients with left ventricular dysfunction with patients with LBBB or right bundle branch block, patients with pacemakers and controls for the evaluation of MD. The parameters of phase analysis were able to identify the subgroups according to the degree of ED. 16 Our findings confirm, as those by Trimble et al., 16 the feasibility of using myocardial perfusion scintigraphy Table 1 - Basal general characteristics Characteristics n = 9 Age, years 62.4 ± 8 Body mass index, kg/m 2 27.3 ± 5.5 Female gender 6 Diabetes Mellitus 5 Hypertension 7 Dyslipidemia 6 Smoking 0 Previous coronary disease 6 Previous infarction 5 CABG surgery 2 Percutaneous Coronary Intervention 1 NYHA functional class II 2 III 5 IV 2 Beta-blocker 9 Angiotensin-converting enzyme inhibitor 3 Angiotensin-receptor blocker 5 Acetylsalicylic acid 2 Diuretics 9 Statins 3 Mineralocorticoid-receptor antagonist 6 Digoxin 4 Results expressed as number or mean ± standard deviation. NYHA: New York Heart Association. Table 2 - Scintigraphic parameters of basal ventricular function of patients included in the study Patients LVEF (%) EDV (mL) ESV (mL) Mass (g) 1 38 287 178 233.5 2 23.5 161 123 175 3 28 143.5 102.5 169 4 35 225.5 146.5 213.5 5 26 210 154 200 6 26.5 325 238 274.5 7 31.5 483.5 333.5 378.5 8 30.5 375.5 260 294 9 26 432 320.5 302.5 Mean ± SD 29.4 ± 4.5 293 ± 112.9 206 ± 80.2 248.9 ± 65 LVEF: left ventricular ejection fraction; EDV: end-diastolic volume; ESV: end-systolic volume; SD: standard deviation.