IJCS | Volume 31, Nº3, May/ June 2018

266 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 (Histogram Bandwidth), S (Skewness) and K (Kurtosis). Potential benefits of the phase analysis technique include its wide availability, automation and reproducibility. 14 All patients in the study were considered as having ED according to the inclusion criteria (QRS width > 150 ms or 120 to 150 ms with ventricular dyssynchrony). MD was defined by the GSPECT phase analysis using the cut-off value SD > 43° and HBW > 135°. Patients who responded to the therapywere defined as having three of the following four criteria: improvement of one functional class; increase of at least 5% of LVEF; reduction of at least 15% of the ESV; and a 5-point increase in the MLHFQ score. This project was submitted to the Research Ethics Committee of Hospital Universitário Antônio Pedro through the Brazil platform, being approved under number 884,844, on November 25, 2014. Statistical analysis Statistical analysis was performed using the Excel program (2010, Microsoft Corporation) and the software Statistical Package for Social Sciences (SPSS), version 21.0 (2012, IBM Corporation), with data shown as means and standard deviations. The One-Sample Kolmogorov- Smirnov test was performed to confirm data normality. The categorical variables were compared using Fisher’s exact test and chi-square test and, as for the numerical variables, the Student’s t-test was used. The linear correlation between the continuous variableswas used for the calculation of Pearson’s linear correlation coefficient. Thephase analysis histogramwas generatedby the Syntool ECT software and correlatedwith theQRS duration, using Pearson’s linear correlation coefficient calculation. The level of statistical significance was set at 5%. Results Fifteen patients were recruited from July 2014 to October 2016. Of these, nine were included in the study, as they were able to complete the exams 6 months after the resynchronizer implantation. The reasons for non- inclusion were: death (two patients died in the fifth month after implantation, one due to heart disease decompensation and another due to severe pneumonia); technical problems (one patient was unable to undergo CRT because of an intraventricular thrombus and another showed no adherence to treatment); loss of follow-up (one patient lost contact with the team); and protocol withdrawal (one patient refused to repeat the scintigraphy 6 months after the implantation). The patients were followed for up a mean time of 193 ± 16 days. All patients underwent anamnesis, MLHFQ, 6-minute Walk Test (6MWT), speckle-tracking echocardiography, andmyocardial perfusion scintigraphy before and after implantation, according to the protocol. The basal general characteristics of the patients included in the study are shown in table 1. The patients had pre-implantation electrocardiograms with controlled heart rate (beta-blocked) and enlarged QRS, with a mean of 214 ± 17 ms – all with LBBB morphology. In the 6MWT, the average distance traveled was 341 ± 77 m. High values of the Minnesota score (63 ± 16) were observed, showing a higher frequency of symptoms in patients. Table 2 shows the scintigraphic parameters of systolic function and basal left ventricular mass of the patients included in the study. Table 3 shows the basal scintigraphic parameters of the phase analysis related to the ventricular synchrony. Two patients did not have MD, according to the scintigraphic criterion (SD > 43°), but only ED. Table 4 shows patients’ clinical response after the cardiac resynchronizer implantation. It was observed that NYHA functional class decreased for all patients with FC > III, with two patients with NYHA IV showing a decrease to NYHA III, and only one FC III patient did not show FC improvement, with statistical significance by Fisher’s exact test. There was a statistically significant reduction in the MLHFQ scores, which, despite being subjective, showed a marked improvement in patients’ symptoms, with quality of life improvement. Regarding the 6-minute Walk Test, there was an increase in the distance covered, a decrease in the Borg index (subjective dyspnea score) and in the dyspnea assessed by the examiner, although not statistically significant. In table 5, the findings of imaging methods in relation to desynchronization were compared. The scintigraphic values of ventricular function (LVEF, EDV, ESV and LV mass) and the values that evaluated dyssynchrony (PP, HBW, SD, S and K) were analyzed. There was a statistically significant reduction in mean systolic volume and LV mass after CRT, due to probable post- resynchronization reverse remodeling. Seve r a l cor r e l a t i ons o f t he dys synchrony scintigraphic parameters with electrocardiographic findings were performed aiming to demonstrate the