EKG Terms and Definitions

Study Notes

EKG Terms and Definitions

P wave: Represents atrial depolarization, the initial electrical activity in the heart that triggers atrial contraction.
Q wave (of QRS complex): Indicates depolarization of the interventricular septum, crucial for proper ventricular functioning.
R wave (of QRS complex): Represents ventricular depolarization. This wave reflects the main electrical stimulus that passes through thick ventricular walls, requiring higher voltage.
S wave (of QRS complex): Signifies depolarization of the Purkinje fibers, which are essential for coordinated ventricular contraction.
T wave: Represents ventricular repolarization, signaling the end of electrical activity in the ventricles, and marks the initiation of ventricular diastole, where refilling occurs.
QT interval: Duration of ventricular contraction, encompassing both depolarization and repolarization phases in the ventricular cycle.
ST segment: A flat line between the end of the QRS complex and the beginning of the T wave. Key for assessing myocardial ischemia and necrosis when deviations occur.
EKG (Electrocardiogram): A graphical representation of the sequence of electrical conduction through the heart muscles, indicating cardiac activity.
QRS complex: Represents the combined electrical activity during ventricular depolarization and indicates silent atrial repolarization occurring simultaneously.
PR interval: Duration of 0.18 seconds, measured from the beginning of the P wave to the beginning of the QRS complex, reflecting the time taken for electrical impulses to travel from the atria to the ventricles.