Assessment of skeletal muscle ventricle function using tissue velocity imaging

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Regenerative Medicine

Background:

• Skeletal muscle ventricles (SMVs) offer potential for circulatory assistance.
• Noninvasive assessment methods are crucial for long-term SMV function studies.
• Evaluating tissue velocity imaging (TVI) for SMV assessment is needed.

Purpose of the Study:

• To determine if TVI indices correlate with invasive measurements of SMV output and pressure generation.
• To explore TVI's capability in assessing SMV geometry and wall contraction.
• To validate TVI as a noninvasive tool for SMV monitoring.

Main Methods:

• SMVs were constructed in six sheep and connected to a mock circulation.
• SMVs were stimulated at 30-Hz and 50-Hz bursts under varying preload and afterload conditions.
• TVI measured wall velocities, calculating a wall motion score (WMS) for comparison with invasive stroke volume, pressure, and stroke work.

Main Results:

• Optimal SMV performance was achieved at 50-Hz stimulation and high preload.
• TVI identified geometric anomalies and dyskinesis at low preloads, which normalized with increased preload.
• Significant correlations were found between WMS and invasive metrics under systemic loading conditions (e.g., stroke volume vs. WMS, r=0.92).

Conclusions:

• TVI indices of SMV wall motion correlate with invasive performance measures under systemic loading.
• TVI shows potential as a valuable tool for noninvasive, long-term monitoring of SMV function.
• Further validation may support TVI's role in clinical applications of SMV-based circulatory support.