Rhythm Classification Task

Overview

The objective of rhythm classification is to detect and classify abnormal heart rhythms, also known as arrhythmias, directly from ECG signals.

Characteristics

There are a variety of heart rhythms that can be detected using ECG signals. In this task, we predominantly focus on detecting arrhythmias such as atrial fibrillation (AFIB) and atrial flutter (AFL). The following table summarizes characteristics of a few rhythms:

SR

Sinus rhythm (SR) is a type of rhythm where the heart beats regularly and originates from the sinus node. SR is considered normal and is typically characterized by the following:

Regular rhythm
P waves present
QRS complexes usually < 120ms
Ventricular rate 60-100 bpm

AFIB

Atrial fibrillation (AFIB) is a type of rhythm where the atria (upper chambers of the heart) beat irregularly and out of sync with the ventricles (lower chambers of the heart). AFIB is the most common type of rhythm and can lead to serious complications such as stroke and heart failure. AFIB is typically characterized by the following:

Irregularly irregular rhythm
No P waves
Variable ventricular rate
QRS complexes usually < 120ms
Fibrillatory waves may be present

AFL

Atrial flutter (AFL) is a type of rhythm where the atria (upper chambers of the heart) beat regularly but faster than normal. AFL is less common than AFIB and can lead to serious complications such as stroke and heart failure. AFL is typically characterized by the following:

Narrow complex tachycardia
Regular atrial activity at ~300 bpm
Loss of the isoelectric baseline
“Saw-tooth” pattern of inverted flutter waves in leads II, III, aVF
Upright flutter waves in V1 that may resemble P waves
Ventricular rate depends on AV conduction ratio

SVT

Supraventricular tachycardia (SVT) is a type of rhythm where the heart beats faster than normal due to abnormal electrical signals originating above the ventricles. SVT is typically characterized by the following:

Narrow complex tachycardia
Regular rhythm
P waves may be absent, hidden, or retrograde
QRS complexes usually < 120ms
Ventricular rate > 100 bpm

BRAD

Sinus bradycardia (BRAD) is a type of rhythm where the heart beats slower than normal due to abnormal electrical signals originating from the sinus node. BRAD is typically characterized by the following:

Regular rhythm
P waves present
QRS complexes usually < 120ms
Ventricular rate < 60 bpm

Dataloaders

Dataloaders are available for the following datasets:

Icentia11k
PTB-XL
LSAD

Pre-trained Models

The following table provides the latest performance and accuracy results for rhythm models. Additional result details can be found in Model Zoo → Rhythm.

NAME	DATASET	FS	DURATION	# CLASSES	MODEL	PARAMS	FLOPS	METRIC
ARR-2-EFF-SM	Icentia11K, PTB-XL, LSAD	100Hz	5s	2	EfficientNetV2	18K	1.2M	99.5% F1
ARR-4-EFF-SM	LSAD	100Hz	5s	4	EfficientNetV2	27K	1.6M	95.9% F1

Target Classes

Below outlines the classes available for rhythm classification. When training a model, the number of classes, mapping, and names must be provided.

CLASS	LABEL	DESCRIPTION
NSR	0	Normal sinus rhythm
SBRAD	1	Sinus bradycardia
STACH	2	Sinus tachycardia
SARRH	3	Sinus arrhythmia
SVARR	4	Supraventricular arrhythmia
SVT	5	Supraventricular tachycardia
VTACH	6	Ventricular tachycardia
AFIB	7	Atrial fibrillation
AFLUT	8	Atrial flutter
VFIB	9	Ventricular fibrillation
VFLUT	10	Ventricular flutter
BIGU	11	Bigeminy (every other beat is PVC)
TRIGU	12	Trigeminy (every third beat is PVC)
PACE	13	Paced rhythm
NOISE	127	Noise

Class Mapping

Below is an example of a class mapping for a 2-class rhythm model. The class map keys are the original class labels and the values are the new class labels. Any class not included will be skipped.

{
    "num_classes": 2,
    "class_names": ["NSR", "AFIB"],
    "class_map": {
        "0": 0,  // Map None to None
        "7": 1,  // Map AFIB to AFIB
        // Skip remaining classes
    }
}