Noninvasive assessment of intraventricular pressure difference in left ventricular dyssynchrony using vector flow...

Area of Science:

• Cardiovascular Physiology
• Medical Imaging
• Echocardiography

Background:

• Diastolic intraventricular pressure difference (IVPD) assesses left ventricular (LV) diastolic function.
• Relative pressure imaging (RPI) noninvasively quantifies IVPD using vector flow mapping (VFM).
• LV dyssynchrony impairs cardiac performance, but its effect on IVPD is unknown.

Purpose of the Study:

• To investigate how LV dyssynchrony modulates IVPD.
• To assess the impact of LV dyssynchrony on diastolic suction and early filling.

Main Methods:

• LV dyssynchrony was induced in dogs via right ventricular (RV) pacing; controls received right atrial (RA) pacing.
• Echocardiography and LV pressure measurements were performed at baseline and during pacing.
• RPI calculated IVPD, specifically ΔP during isovolumic relaxation time (ΔP_IRT) and early filling (ΔP_E).

Main Results:

• RV pacing significantly decreased stroke volume (SV) and ΔP_IRT, but not ΔP_E.
• RA pacing did not significantly alter SV, ΔP_IRT, or ΔP_E.
• ΔP_IRT correlated with ejection fraction and end-systolic volume; LV dyssynchrony reduced ΔP_IRT but not ΔP_E.

Conclusions:

• LV dyssynchrony reduces IVPD during isovolumic relaxation time, indicating impaired diastolic suction.
• The observed reduction in diastolic suction is significantly linked to decreased stroke volume.
• RPI is a valuable tool for assessing IVPD and its modulation by LV dyssynchrony.