Relationships between left ventricular asynchrony and myocardial blood flow

Area of Science:

• Cardiovascular Imaging
• Nuclear Cardiology
• Physiology

Background:

• Rubidium-82 (⁸²Rb) PET allows assessment of left ventricular asynchrony (LVAS) and myocardial blood flow (MBF) at rest and during stress.
• Left ventricular asynchrony (LVAS) can be present at rest and may change with stress, impacting cardiac function.
• Myocardial blood flow (MBF) assessment provides insights into coronary artery disease and cardiac health.

Purpose of the Study:

• To investigate the relationship between myocardial blood flow (MBF) and changes in left ventricular asynchrony (LVAS) in patients with resting LVAS.
• To determine if MBF characteristics during stress can predict improvement or deterioration of LVAS.
• To identify predictors of stress-induced improvement in LVAS among patients with baseline asynchrony.

Main Methods:

• Retrospective analysis of 195 patients undergoing ⁸²Rb rest/regadenoson stress PET studies.
• Measurement of MBF from first-pass data and LVAS from myocardial equilibrium data (phase contraction bandwidth).
• Definition of LVAS improvement/deterioration based on changes in phase contraction bandwidth relative to normal limits.

Main Results:

• Among 64 patients with resting LVAS, 13 improved and 51 did not.
• Patients without LVAS improvement had significantly lower stress MBF and coronary flow reserve (CFR) compared to those who improved.
• Reduced MBF heterogeneity during stress was the strongest predictor of LVAS improvement (84% accuracy).

Conclusions:

• LVAS is strongly correlated with MBF and CFR.
• Stress-induced improvement in cardiac synchrony is most significantly associated with improved MBF homogeneity.
• ⁸²Rb PET provides valuable information on both cardiac synchrony and myocardial perfusion.