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AI in Heart Disease Detection: How AI-ECG Detects Early Heart Dysfunction
(Paper Presentation Supplement — to be used alongside the main presentation)
Introduction
As outlined in the main presentation (Slide 2–4), artificial intelligence is transforming the role of electrocardiography in cardiovascular care. This supplement provides a deeper technical dive into two core mechanisms by which AI-ECG detects early heart dysfunction: subtle pattern recognition and ejection fraction estimation — both of which are central to the diagnostic pipeline described in Slide 6 of the main deck.
1. Subtle Pattern Recognition: Algorithms Processing Raw 10-Second, 12-Lead Voltage Matrices
The Input: Raw Voltage Data
When a standard 12-lead ECG is acquired, the device records 10 seconds of voltage-time series data across 12 leads. This produces a voltage matrix — typically 12 leads × 5,000 time points (at 500 Hz sampling) — representing the electrical activity of the heart from multiple spatial angles. Conventional ECG interpretation relies on morphological features such as QRS duration, ST-segment deviations, and T-wave amplitudes — features visible to the trained human eye.
What AI Sees That Humans Cannot
AI models — particularly deep convolutional neural networks (CNNs) — process this raw voltage matrix in its entirety, without relying on pre-defined morphological rules. The algorithm scans the entire 10-second, 12-lead signal to detect non-linear micro-variations and subtle temporal and morphological patterns that are imperceptible to human interpretation.
Recent research has shown that AI-ECG algorithms can identify what are termed “electrophysiological signatures” — subtle, non-linear morphologic shifts in the QRS-T complex and P-wave morphology that reflect underlying structural remodeling or metabolic disturbances in the myocardium. These patterns may represent subclinical myocardial changes long before they manifest as overt ECG abnormalities or clinical symptoms.
The ECG signal contains rich non-linear and non-stationary dynamic information that is only partly captured by conventional interpretation. AI models are uniquely suited to extract this information because they:
Analyze the entire voltage matrix holistically rather than through isolated measurements
Detect multi-lead spatial relationships that indicate diffuse myocardial involvement
Identify beat-to-beat variability patterns that evolve over seconds to minutes
Clinical Relevance
This capability has profound implications. As noted in the main presentation (Slide 4), AI models can detect hidden cardiac conditions — such as low ejection fraction and cardiac amyloidosis — from a routine 12-lead ECG, even when the ECG appears normal to the clinician. The algorithm essentially “sees” electrical signatures of structural heart disease that precede visible ECG changes, enabling earlier detection of dysfunction.
2. Ejection Fraction Estimation: Targeting Silent Left Ventricular Systolic or Diastolic Dysfunction
The Clinical Problem
Left ventricular ejection fraction (LVEF) is an essential indicator for evaluating cardiac function. Reduced ejection fraction — typically defined as LVEF ≤ 40% — is a key marker of heart failure with reduced ejection fraction (HFrEF). However, echocardiography — the gold standard for EF measurement — is often inaccessible in primary care, emergency, and resource-limited settings due to cost, complexity, and the need for specialized training.
How AI-ECG Estimates Ejection Fraction
AI-ECG models address this gap by estimating LVEF directly from the 12-lead ECG voltage data. The approach works as follows:
Training Phase: The AI model is trained on large datasets pairing 12-lead ECGs with echocardiogram-derived EF measurements. For example, one model was trained on over 100,000 ECG images paired with ECHO reports. The model learns to map the subtle ECG voltage patterns to specific EF values.
Inference Phase: When a new 10-second 12-lead ECG is acquired, the algorithm analyzes the voltage matrix and outputs either:
A binary result: likelihood of LVEF ≤ 40% (low ejection fraction)
A continuous estimate: predicted EF value (e.g., with a mean absolute error of 4.57%)
Model Architectures
Multiple deep learning architectures have been successfully applied:
Convolutional Neural Networks (CNNs): Process the 12-lead voltage data through multiple 2D convolutional layers to extract spatial and temporal features
Two-branch models (e.g., ECGEFNet): Integrate both raw numerical signals and waveform plots, incorporating temporal, spatial, and phase information for joint EF calculation
Transformer-based models: Modern deep learning approaches achieving AUROC of approximately 0.86 for EF estimation
Performance Evidence
The clinical performance of AI-ECG for EF estimation is well-documented:
Metric Finding Source
Sensitivity 84.5% (95% CI: 82.2%–86.6%) Multisite validation of FDA-cleared algorithm
Specificity 83.6% (95% CI: 82.9%–84.2%)
AUROC 0.92 (95% CI: 0.91–0.93) External validation across 13,960 subjects
Screening accuracy 92.3% ECGEFNet model for cardiac dysfunction
Negative predictive value 98.4% (95% CI: 98.2%–98.7%) Suggests utility as a rule-out strategy
A systematic review and meta-analysis concluded that ECG-based AI models demonstrate high sensitivity and specificity for estimating LVEF below 40%.
Categorizing Subclinical Risk
AI-ECG models can categorize patients across the spectrum of ejection fraction:
Reduced EF (≤40%): Overt heart failure with reduced ejection fraction — the primary target of most FDA-cleared algorithms
Mildly reduced EF (41–49%): Borderline dysfunction that may progress; AI models can flag these patients for closer monitoring
Preserved EF (>50%): Normal ejection fraction; negative AI-ECG results can help defer unnecessary echocardiography
As noted in the main presentation (Slide 4), recent systems have specifically targeted low ejection fraction and cardiac amyloidosis — demonstrating the expanding scope of AI-ECG diagnostics.
Connection to the Main Presentation
This technical supplement directly supports several slides in the main deck:
Slide 3 (“AI-Powered ECG Analysis”): The subtle pattern recognition mechanism described here explains how AI models learn subtle patterns in 12-lead ECG signals and detect hidden cardiac conditions.
Slide 4 (“AI + Medical Imaging”): EF estimation from ECG is a form of multimodal AI — using ECG (a simple, widely available test) to predict findings normally requiring echocardiography (imaging).
Slide 5 (“Recent Development: ECG Foundation Models”): The ECG-LLM study (679,112 ECG studies from 186,409 patients) represents the next evolution — moving from fixed classifiers to question-driven cardiovascular reasoning.
Slide 8 (“Advantages”): The performance data above validates the claimed advantages — faster analysis, detection of subtle patterns, risk prediction, and decision support.
Slide 10 (“Future Scope”): Real-time monitoring via wearables and on-device AI for remote settings are natural extensions of the EF estimation capability described here.
References
Tran HH, Thu A, Fuertes A, et al. Electrocardiogram-Based Artificial Intelligence for Detection of Low Ejection Fraction: A Contemporary Review. Cardiology in Review. 2025.
Carter RE, et al. Multisite, External Validation of an AI-Enabled ECG Algorithm for Detection of Low Ejection Fraction. JACC Adv. 2026;5(2):102537.
FDA 510(k) Summary: ECG-AI Low Ejection Fraction (LEF) 12-Lead Algorithm (K250652). Anumana, Inc.
Qi Y, et al. ECGEFNet: A two-branch deep learning model for calculating left ventricular ejection fraction using electrocardiogram. Artif Intell Med. 2025.
Devkota A, et al. AI analysis for ejection fraction estimation from 12-lead ECG. Sci Rep. 2025;15(1):13502.
Ferreira ALC, et al. Diagnostic accuracy of artificial-intelligence-based electrocardiogram algorithm to estimate heart failure with reduced ejection fraction: A systematic review and meta-analysis. Curr Probl Cardiol. 2025;50(4):103004.
Selivanov A, Jungmann F, Kehrer J, et al. ECG-LLM: Foundation Model for ECG-Based Cardiac Reasoning. arXiv:2607.16323. 2026.
Narayana Health Develops AI Model to Predict Heart Function from ECG Images. Health IT. 2025.
This supplement is intended to accompany the main presentation “Artificial Intelligence in Modern Heart Disease Diagnosis” and should be referenced during Slides 3–6 for technical depth.
first slide contain title AI in heart disease detection and presented by S.Aravinthan and T.Deepak college name Paavai Engineering College and add last slide contain Thank you and add some data graphs for refernces