Automatic classification of long-term ambulatory ECG records according to type of ischemic heart disease

Aleš Smrdel1, Franc Jager

  • 1University of Ljubljana, Faculty of Computer and Information Science, Tržaška 25, 1000 Ljubljana, Slovenia. ales.smrdel@fri.uni-lj.si

Insights

An automated algorithm accurately analyzes ambulatory electrocardiographic (AECG) data to distinguish between elevated and depressed ST segment episodes, aiding in the classification of ischemic heart disease types.

Area of Science:

  • Cardiology
  • Biomedical Engineering
  • Medical Informatics

Background:

  • Ambulatory electrocardiographic (AECG) records show distinct ST segment patterns in different types of myocardial ischemia.
  • Elevated ST segments typically indicate transmural ischemia (e.g., Prinzmetal's angina), while depressed segments suggest subendocardial ischemia (e.g., unstable or stable angina).
  • The large volume of AECG data necessitates automated analysis methods for accurate interpretation.

Purpose of the Study:

  • To develop and evaluate an algorithm for automatically determining the type of transient ischemic episodes (ST segment elevations or depressions) in AECG records.
  • To classify AECG records based on the type of ischemic heart disease present, including Prinzmetal's angina, other coronary artery diseases, and other heart diseases.

Main Methods:

  • The algorithm was developed and tested using 24-hour AECG records from the Long Term ST Database (LTST DB).
  • It generates ST segment level and reference functions to derive ST segment deviation functions, accounting for non-ischemic changes.
  • The algorithm uses the third statistical moment of the ST segment deviation function's histogram to identify ST segment deflections and classify ischemic events.

Main Results:

  • The algorithm correctly identified the type of ST segment deflections in the majority of leads across 74 LTST DB records.
  • It accurately classified most Prinzmetal's angina records (7/8) and other coronary artery disease records (47/55).
  • Classification accuracy for other heart diseases was 1 out of 11 records.

Conclusions:

  • The developed algorithm is efficient and suitable for processing extensive AECG data.
  • It demonstrates effectiveness in classifying the majority of records based on transient ischemic heart disease type.
  • This automated approach aids in the analysis of complex AECG data for improved diagnostic capabilities.
Abstract

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