Multiple instance learning framework can facilitate explainability in murmur detection

Maurice Rohr1, Benedikt Müller1, Sebastian Dill1

  • 1KIS*MED - AI Systems in Medicine, Technische Universität Darmstadt, Darmstadt, Germany.

PLOS Digital Health
|March 19, 2024
PubMed

Insights

This study introduces a novel explainable multitask model using multiple instance learning (MIL) to detect heart murmurs from phonocardiograms (PCGs). The model accurately predicts murmurs and clinical outcomes, improving cardiovascular disease diagnosis.

Area of Science:

  • Cardiology
  • Biomedical Engineering
  • Machine Learning

Background:

  • Cardiovascular diseases (CVDs) are a leading cause of global mortality.
  • Heart murmurs detected via phonocardiograms (PCGs) can indicate CVDs but often require expert interpretation.
  • Current methods may overlook subtle murmur indicators or lack explainability.

Purpose of the Study:

  • To develop an explainable multitask model for predicting heart murmurs and clinical outcomes from multiple PCG recordings.
  • To leverage multiple instance learning (MIL) for improved murmur detection and localization.
  • To integrate explainable features for enhanced clinical decision support.

Main Methods:

  • A two-stage multitask model incorporating MIL in the first stage for murmur detection in single PCGs.
  • Fusion of explainable hand-crafted features with features from a pooling-based artificial neural network (PANN) in the second stage.
  • Prediction of patient-specific murmur presence and clinical outcome using multiple PCG recordings via a feed-forward neural network.

Main Results:

  • The MIL approach effectively identifies murmur locations and provides useful features for PCG analysis.
  • The PANN model achieved a weighted accuracy of 0.714 on the CirCor dataset.
  • The model demonstrated competitive classification performance for murmur detection and clinical outcome prediction.

Conclusions:

  • This work is the first to demonstrate the utility of MIL for phonocardiogram classification.
  • The study highlights a method for quantitative analysis of model explainability, mitigating confirmation bias.
  • The findings underscore the value of combining MIL with handcrafted features for explainable AI in cardiovascular diagnostics.
Abstract