Physiological Characterisation of Severe Heart Failure Using Long-Duration Ambulatory ECG: A Retrospective...

Area of Science:

• Cardiology
• Physiology
• Medical Technology

Background:

• Heart failure (HF) involves progressive autonomic and cardiorespiratory dysregulation.
• Episodic clinical assessments incompletely capture these complex physiological dynamics.
• Continuous ambulatory electrocardiogram (ECG) monitoring offers a unique window into longitudinal HF physiology.

Purpose of the Study:

• To provide a descriptive and exploratory physiological characterization of cardiac and respiratory dynamics in severe heart failure (HF) patients.
• To utilize long-duration ambulatory ECG recordings for this detailed analysis.
• To investigate inter-individual variability and within-subject temporal patterns.

Main Methods:

• Retrospective analysis of the Beth Israel Deaconess Medical Center (BIDMC) Congestive Heart Failure database.
• Utilized approximately 20 hours of two-channel ambulatory ECG from 15 NYHA class III-IV HF patients.
• Derived heart rate (HR), heart rate variability (HRV), and ECG-derived respiration (EDR) using automated ECG annotations.

Main Results:

• Observed marked heterogeneity in mean HR and HRV across subjects, with generally depressed HRV indicating autonomic dysfunction.
• Longitudinal analyses revealed substantial within-subject variability and temporal trends in HR and EDR.
• Found partial dissociation between HR and HRV, highlighting limitations of single-parameter assessments.

Conclusions:

• Long-duration ambulatory ECG provides rich physiological characterization of cardiac and respiratory function in severe HF.
• Findings are exploratory and hypothesis-generating for future research.
• Establishes a physiological foundation for studies integrating clinical data and wearable technologies.