electrocardiology

Electrocardiology is a subspecialty of cardiology focused on the heart’s electrical activity and its clinical manifestations. It centers on rhythm and conduction assessment using the electrocardiogram (ECG or EKG) and related noninvasive and invasive studies used to diagnose and treat electrical disorders of the heart.

The electrocardiogram was developed in the early 20th century by Willem Einthoven, who established the standard limb leads and the dipole model of cardiac electrical activity. Modern practice uses a 12-lead ECG and continuous monitoring to visualize heart function across different states and activities.

Key concepts include the cardiac conduction system (SA node, AV node, His-Purkinje network) and the ECG’s depolarization and repolarization waves. The P, QRS, and T waves, as well as intervals such as PR, QRS duration, and QT, guide interpretation alongside rhythm, axis, and artifacts.

Common tools include the standard 12-lead ECG, Holter and event monitors for ambulatory assessment, and exercise stress testing. Invasive evaluation with intracardiac electrophysiology studies (EPS) maps electrical activation and can enable ablation of arrhythmogenic tissue and optimization of device therapy.

Electrocardiology aids diagnosis and characterization of arrhythmias (e.g., atrial fibrillation, ventricular tachycardia), ischemia, and conduction disorders. It informs treatment decisions, including antiarrhythmic drugs, catheter ablation, and the use of pacemakers or implantable cardioverter-defibrillators.

Emerging trends include wearable ECG devices, remote monitoring, and AI-assisted interpretation to improve accuracy and risk assessment.