Mechanical Dispersion Discriminates between Arrhythmic and Non-Arrhythmic Sudden Death: From the POST SCD Study

Area of Science:

• Cardiology
• Pathology
• Medical Imaging

Background:

• Sudden cardiac death (SCD) prediction often relies on left ventricular ejection fraction (LVEF), but global longitudinal strain (GLS) and mechanical dispersion (MD) may offer additional insights.
• Previous studies lacked definitive autopsy confirmation for cardiac causes of SCD.
• This study investigates the association between GLS, MD, and autopsy-defined sudden arrhythmic death (SAD).

Approach:

• A comprehensive postmortem study identified and autopsied individuals aged 18-90 with presumed SCD.
• Pre-mortem echocardiograms were analyzed for LVEF, LV-GLS, and MD.
• Histological examination quantified left ventricular (LV) myocardial fibrosis.

Key Points:

• Autopsy-confirmed SAD cases showed significantly reduced LV-GLS and increased MD compared to non-SADs.
• Increased MD correlated with higher levels of LV fibrosis in SAD patients.
• LVEF did not differ significantly between SAD and non-SAD groups.

Conclusions:

• Mechanical dispersion (MD) and global longitudinal strain (GLS) are valuable predictors of sudden arrhythmic death (SAD) beyond LVEF.
• MD serves as a non-invasive surrogate marker for myocardial fibrosis.
• These echocardiographic parameters can enhance risk stratification for SCD.