Mechanical dyssynchrony in advanced decompensated heart failure: Relation to hemodynamic responses to intensive medical therapy

Background: In patients with heart failure, the degree of intraventricular mechanical dyssynchrony (intra-VMD) at baseline may predict reversal of cardiac remodeling with cardiac resynchronization therapy (CRT). Objective: The purpose of this study was to determine the prevalence and clinical significance of intra-VMD in patients admitted for advanced decompensated heart failure (ADHF). Methods: We prospectively enrolled 50 patients with ADHF without previous CRT implantation who had been admitted to a specialized heart failure intensive care unit because of hemodynamic derangements. All patients underwent comprehensive echocardiographic evaluation within 12 hours of admission and after 48 hours from baseline evaluation after intensive medical therapy. Intra-VMD was assessed by the opposing wall time-to-peak myocardial velocity intervals in a four-segment model using color-tissue Doppler imaging. Results: In our study cohort (mean age 57 ± 11 years, left ventricular ejection fraction 26 ± 10%, QRS width 127 ± 31 ms, cardiac index 2.0 ± 0.6 L/min/m²), significant intra-VMD (≥65 ms) was present in 44% of subjects at baseline, and 56% of patients presented with QRS >120 ms. There was no correlation between QRS width and extent of intra-VMD. Intensive medical therapy was associated with a significant reduction in intra-VMD (85 ± 23 ms vs. 39 ± 19 ms; P <.001). Significant hemodynamic improvement in cardiac index, filling pressures, and systemic and pulmonic vascular resistance was seen only in patients with intra-VMD. Conclusion: A substantial subset of patients admitted with ADHF and hemodynamic derangements demonstrate evidence of intra-VMD, which is reduced at follow-up and independent of underlying QRS width. Nevertheless, the presence of significant intra-VMD is associated with a more reversible hemodynamic profile.