Non-Invasive Detection of Mechanical Alternans Utilizing Photoplethysmography

Area of Science:

• Biomedical Engineering
• Cardiology
• Medical Diagnostics

Background:

• Mechanical alternans (MA) is a significant predictor of mortality and life-threatening arrhythmias in heart failure patients.
• Current methods for MA detection require continuous blood pressure monitoring, which is invasive, costly, and impractical for widespread clinical use.

Purpose of the Study:

• To develop and validate non-invasive surrogates for mechanical alternans (MA) using photoplethysmography (PPG) signals.
• To establish the feasibility of using PPG for MA detection as a clinical tool.

Main Methods:

• Continuous blood pressure and PPG data were collected from 35 heart failure patients undergoing ventricular pacing or exercise tests.
• MA was induced and categorized as sustained or intermittent.
• Eight pulse morphology features from PPG were analyzed to derive and evaluate MA surrogates.

Main Results:

• A PPG-based MA surrogate, V'M, derived from the first derivative of the PPG pulse, demonstrated high accuracy.
• V'M achieved 100% sensitivity and 100% specificity in detecting sustained and intermittent MA in one patient group.
• The surrogate showed strong linear correlation with MA magnitude (R² = 0.83, p < 0.001).

Conclusions:

• Photoplethysmography analysis enables accurate, non-invasive identification of mechanical alternans.
• This non-invasive approach holds significant potential for improving risk stratification and enabling remote monitoring of heart failure patients.