Analysis of mechanical ventricular synchrony of patients with systemic sclerosis

The analysis of ventricular synchrony is important and complex in different cardiac diseases because it provides additional prognostic and diagnostic information. Insufficient information is available regarding the analysis of ventricular synchrony in patients diagnosed with systemic sclerosis (SSc) at a Nuclear Cardiology Unit.

To assess the mechanical ventricular synchrony of patients with SSc.

Prospective cohort study of sixty-two patients (age 56.8 ± 12.9 years, men 12.9%) with SSc. All patients were studied with gated Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging (gSPECT-MPI) and Emory Cardiac ToolboxTM program during rest, exercise and cold test. The normal cut-off value for the dyssynchrony parameters (standard deviation [SD] > 18.4º, bandwidth [BD] > 51º, skewness [S] ≤ 3.2 and kurtosis [K] ≤ 9.3) were previously published and validated as well as its degrees. Statistical analyses were performed using ANOVA with Bonferroni correction and logistic regression analysis (STATA 18. StataCorp, College Station, TX, USA).

The prevalence of ventricular mechanical dyssynchrony (VMD) (SD > 18.4º and/or BD > 51ª) at rest was high (n=40, 64.5%) and a normal ventricular mechanical synchronization was detected in 22 (35.5%) patients. Of the patients with VMD (n=40), 3 (3/40: 7.5%) had slight VMD (degree 1) and 37 (37/40: 92.5%) had moderate-severe (degrees 2-4) VMD.

There was no significant difference in BD (64.2 30, 62.3 36, 52.7 23) and SD (21.8 ± 12.6, 20.8 ± 9.6, 18.5 ± 7.6) between rest, exercise and cold test, respectively (ANOVA with Bonferroni correction). Only S (3.6 ± 0.8 vs 4 ± 0.9, p = 0.027) and K (14.8 ± 8 vs 18.7 ± 8.4, p = 0.033) were lower during exercise in comparison to rest, and the remainder combination without any significant difference.

Patients with VMD at rest had lower peak filling rate (PFR) (1.8 ± 0.5 vs 2.2 ± 0.46, p = 0.025) and a higher summed thickening score (STS) at rest (4.6 ± 10 vs 1.7 ± 6, p = 0.045) compared with patients with normal mechanical synchronization. We have defined probable VMD when a patient had diastolic dysfunction (PFR<18) and/or abnormal ventricular motility (STS >0). By mean of logistic regression analysis we have created a model adjusted by age, gender and previous cardiac event (CE) with a good prediction for VMD (AUC ROC: 0.76 (95% CI: 0.62 to 0.88), standard error: 0.065). (Results Table).

VMD has an elevated prevalence in patients with SSc. No significant differences are observed in BD and SD parameters between rest, exercise and cold tests. Furthermore, this study explains how we can calculate the pretest probability of VMD in patients with SSc.