Skip to main content
Pearson+ LogoPearson+ Logo
Back

Electrocardiogram (ECG) definitions

Control buttons has been changed to "navigation" mode.
1/15
  • Electrocardiogram
    A recording of the heart's electrical activity, used to assess heart function and diagnose conditions.
  • Electrocardiograph
    The machine that records the heart's electrical activity using electrodes placed on the body.
  • Depolarization
    The process by which cardiac cells become electrically charged, leading to muscle contraction.
  • Repolarization
    The process of cardiac cells returning to their resting electrical state after depolarization.
  • P wave
    The part of an ECG that represents atrial depolarization.
  • QRS complex
    The part of an ECG that represents ventricular depolarization.
  • T wave
    The part of an ECG that represents ventricular repolarization.
  • Bradycardia
    A condition where the heart rate is slower than normal, below 60 beats per minute.
  • Tachycardia
    A condition where the heart rate is faster than normal, above 100 beats per minute.
  • Fibrillation
    Uncoordinated contraction of heart muscle fibers, leading to ineffective pumping.
  • Atrial fibrillation
    A type of fibrillation affecting the atria, often not immediately life-threatening.
  • Ventricular fibrillation
    A type of fibrillation affecting the ventricles, usually fatal without immediate treatment.
  • Heart block
    A condition where the electrical signal from the atria to the ventricles is disrupted.
  • AV node
    A part of the heart's electrical conduction system that delays the signal before it reaches the ventricles.
  • ST segment
    The flat section of an ECG between the QRS complex and the T wave, indicating ventricular contraction.