Introduction:
Cardiac resynchronization therapy (CRT) optimization can be performed using the non-invasive cardiac system (NICaS), a diagnostic instrument that offers two independent types of measurements: 1.cardiac output and derivatives; 2.the Granor-Goor index(GGI) for left ventricular systolic function assessment.We sought to define predictors for acute hemodynamic improvement during NICaS guided CRT optimization
Methods:
Forty patients with CRT systems implanted >6 months, regardless of response status, were enrolled in the NICaS CRT trial (identifier NCT02126241), a non-randomized interventional prospective study in which NICaS guided atrio-ventricular (AV) and inter-ventricular (VV) delays optimization.Baseline assessment included medical history, clinical evaluation, echocardiography and NICaS hemodynamic measurements (cardiac index (CI), stroke volume index (SVi), GGI).CRT optimization was done according to a pre-specified protocol using sequential changes of 30 ms for AV delay followed by VV delay. CI and SVi were re-assessed by NICaS for each new set of parameters. Acute hemodynamic improvement was defined as an increase of 10% in CI/SVi compared to baseline.
Results:
During NICaS guided CRT optimization, 50% of the patients presented acute hemodynamic improvement.These patients had higher prevalence of ischemic heart disease (75%vs.35%;p=0.01) and non-response to CRT (55%vs.25%;p=0.05).Moreover, they had lower ejection fraction (31±11% vs.36±15%;p=0.07) and worse baseline hemodynamic parameters (CI 2.25±0.51 vs. 2.65±0.73 l/min/m2, p = 0.09; SVi 34±7 vs. 42±11 ml, p=0.007).Baseline GGI did not differ significantly between improved and not improved patients (8.9±2.1 vs. 10.6±2.7; p=0.12). In univariate analysis, baseline GGI was associated with acute hemodynamic improvement (OR 0.74;p=0.03).In fact, baseline GGI>11.5 was an independent predictor for no hemodynamic improvement (OR 9.6; p=0.04) with a positive predictive value of 88%, after correction for non-response to CRT
Conclusions:
Baseline GGI predicted acute hemodynamic improvement during NICaS guided CRT optimization.A baseline GGI cut-off of 11.5 could be possibly used in order to outline those who may benefit from NICaS CRT optimization
