Reduced Left Ventricular Global Longitudinal Strain in the Coronary Slow Flow Phenomenon: A Systematic Review and...

CSFP is associated with a significant reduction in left ventricular global longitudinal strain (LVGLS) despite preserved left ventricular ejection fraction (LVEF).Layer-specific strain analysis reveals the most pronounced impairment in the endocardial layer.LVGLS demonstrates moderate-to-high diagnostic accuracy for detecting CSFP (pooled AUC: 0.80).These findings support LVGLS as a noninvasive marker of subclinical myocardial dysfunction in CSFP.

The coronary slow flow phenomenon (CSFP) involves delayed coronary artery filling without obstruction and is associated with angina and myocardial ischemia. This meta-analysis assessed the link between CSFP and impaired left ventricular global longitudinal strain (LVGLS), a marker of subclinical myocardial dysfunction.

A systematic search (PubMed, Embase, Scopus up to January 2025) identified 18 observational studies comparing LVGLS and layer-specific strain in patients with CSFP vs controls with normal coronary flow.

Patients with CSFP showed significantly reduced LVGLS vs controls (SMD, 1.22; 95% CI, 0.69 to 1.75). Layer-specific analysis revealed impairment across all myocardial layers, most pronounced in the endocardium (SMD, 0.79; 95% CI, 0.21 to 1.38). While left ventricular ejection fraction (LVEF) was preserved, LVGLS demonstrated moderate-to-high diagnostic accuracy for CSFP (AUC, 0.80; 95% CI, 0.66 to 0.95). Reduced LVGLS independently predicted CSFP (adjusted OR, 1.43; 95% CI, 1.19 to 1.46). Exercise stress effects on LVGLS were inconsistent.

CSFP is associated with impaired LVGLS, particularly in the endocardial layer, despite preserved LVEF. LVGLS may serve as a noninvasive marker for subclinical dysfunction in CSFP.