Objective:

To evaluate the predictive and prognostic significance of hemodynamic force (HDF) parameters in patients undergoing cardiac resynchronization therapy (CRT) and examine changes after CRT implantation.

Approach:

• Study Design: A post hoc analysis of 198 patients from the prospective, multicenter, observational MARC study, using archived echocardiographic images.
• HDF Parameters Evaluated: Apical-basal force, latero-septal force, their ratio, force vector angle, systolic apical-basal force, and systolic angle.
• Response Definition: CRT response is defined as a ≥15% reduction in left ventricular end-systolic volume at 6 months.
• Statistical Analysis: Models assess associations with CRT response and the incremental value of HDF parameters. Cox regression evaluates the composite endpoint of all-cause mortality or cardiovascular hospitalization during long-term follow-up.

Key Findings:

• At 6 months, 120 patients (60.6%) demonstrate echocardiographic response to CRT.
• Adding baseline systolic angle to established clinical, electrocardiographic, and echocardiographic markers significantly improves model fit for CRT response but does not significantly improve discrimination.
• Responders show significant improvements in HDF parameters after CRT; nonresponders show no significant changes.
• Baseline systolic angle is independently associated with all-cause mortality or cardiovascular hospitalization over a median follow-up of 9.3 years. Its addition improves prognostic model performance but does not significantly improve discrimination.

Interpretation:

HDF parameters provide complementary insight into ventricular mechanics in patients undergoing CRT. Baseline systolic angle is independently associated with reverse remodeling and long-term outcomes, but its incremental clinical predictive value remains uncertain.

Limitations:

• This post hoc analysis is not specifically powered for these outcomes and includes a selected population meeting 2012 CRT guideline criteria, limiting generalizability to contemporary patients.
• Systolic angle differences are small, approximately 1°–2°, and approach the technique’s measurement precision. Systolic angle has the lowest reproducibility among the HDF parameters.
• HDF analysis requires high-quality images and careful measurements. Systematic cardiac magnetic resonance assessment of myocardial scar is unavailable.
• The exploratory systolic angle threshold requires external validation. Device programming and biventricular pacing percentage are not incorporated into multivariable models.

Conclusion:

HDF assessment shows potentially relevant associations with CRT response and long-term outcomes, but adding systolic angle does not significantly improve discrimination. Further adequately sized, prospective studies in contemporary populations are needed to establish clinical value.

Sources:

• Echocardiography-Derived Hemodynamic Forces in Cardiac Resynchronization Therapy: Association with Reverse Remodeling and Long-Term Outcomes