Cardiac vulnerability assessment from electrical microvariability of high-resolution electrocardiogram

Area of Science:

• Cardiology
• Biomedical Engineering
• Signal Processing

Background:

• Malignant arrhythmias are often preceded by increased T-wave variability on electrocardiograms.
• T-wave variability analysis is a developing method for non-invasive risk stratification.
• Intra-QRS and ST-T segment variations are less explored in this context.

Purpose of the Study:

• To investigate intra-QRS beat-to-beat signal variation.
• To compare intra-QRS variation with ST-T segment variation.
• To assess these variations as potential biomarkers for malignant arrhythmia risk.

Main Methods:

• Analyzed beat-to-beat microvolt variation in QRS and ST-T segments from high-resolution electrocardiograms.
• Included 44 high-risk coronary heart disease patients and 51 healthy volunteers.
• Applied a cubic spline filter and calculated integrated standard deviation for variability indices.

Main Results:

• High-risk patients exhibited significantly higher QRS variability (median 44.5 ms vs 34.7 ms, p < 0.001).
• High-risk patients also showed significantly higher ST-T segment variability (median 20.5 ms vs 9.8 ms, p < 0.001).
• Discriminative ability was comparable between QRS (7.8) and ST-T (12.6) variability indices.

Conclusions:

• Increased beat-to-beat microvolt variation in both QRS and ST-T segments characterizes patients at high risk for malignant arrhythmias.
• These findings support the potential of depolarization variability analysis for risk assessment.
• Further research is needed to confirm the prognostic value of depolarization variability.