Mechanical Dispersion in Dilated and Non-Dilated Left Ventricular Cardiomyopathy: A New Frontier in Arrhythmic Risk...

Area of Science:

• Cardiology
• Biomedical Engineering
• Electrophysiology

Background:

• Sudden cardiac death (SCD) remains a significant risk in dilated (DCM) and non-dilated left ventricular cardiomyopathy (NDLVC).
• Current risk stratification using ejection fraction, scar burden, and genetics is insufficient for accurate prediction.
• Mechanical dispersion (MD) from speckle-tracking echocardiography offers a potential marker for arrhythmic risk by assessing regional contraction timing variability.

Purpose of the Study:

• To review the predictive value of MD for ventricular arrhythmias (VA) and SCD in DCM and NDLVC.
• To examine the relationship between MD, myocardial fibrosis (MF), and established echocardiographic markers.

Main Methods:

• Narrative review of prospective and retrospective studies.
• Analysis of data from speckle-tracking echocardiography for MD calculation.
• Comparison of MD with left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), and late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR).

Main Results:

• Increased MD consistently predicts higher arrhythmic risk in DCM patients, often independent of LVEF and GLS.
• Risk prediction thresholds for MD range from 50 ms to 90 ms, with significant hazard ratios.
• The correlation between MD and myocardial fibrosis (MF) is complex; VA can occur with or without detectable fibrosis, suggesting other contributing factors.

Conclusions:

• Mechanical dispersion (MD) shows promise for enhancing SCD risk stratification in DCM and NDLVC.
• MD may capture arrhythmogenic substrate components missed by conventional markers.
• Further research is needed to fully elucidate the mechanisms linking MD, fibrosis, and arrhythmias.