Electrocardiography (ECG) I Vocabulary

Flashcards covering key vocabulary and concepts from the Electrocardiography (ECG) I lecture.

Pulmonary Circuit

Pumps blood through the lungs to oxygenate the blood and remove carbon dioxide.

Systemic Circuit

Delivers oxygen and nutrients to tissues and removes carbon dioxide.

Rhythm Generators

Produce an electrical signal (SA node or normal pacemaker).

Conductors

Spread the pacemaker signal.

Contractile Cells (Myocardium)

Mechanically pump blood.

Heart's Pacemaker Cells

Specialized pacemaker cells that start the electrical sequence of depolarization and repolarization.

Inherent Rhythmicity/Automaticity

Cardiac tissue's property of inherent rhythmicity or automaticity.

SA Node

The normal pacemaker of the heart.

Systole

Mechanical event where contractile cells contract.

Diastole

Mechanical event where myocardial cells relax.

Sympathetic Division

Increases automaticity and excitability of the SA node, thereby increasing heart rate.

Parasympathetic Division

Decreases automaticity and excitability of the SA node, thereby decreasing heart rate.

Electrocardiogram (ECG)

Record of the heart's electrical signal.

ECG

Electrical events of the cardiac cycle.

Ventricular Systole and Diastole

Represent mechanical events (contraction and relaxation of cardiac muscle, passive opening and closing of intracardiac valves, etc.).

Isoelectric Line

Point of departure of the electrical activity of depolarizations and repolarizations of the cardiac cycles.

Interval

A time measurement that includes waves and/or complexes.

Segment

A time measurement that does not include waves and/or complexes.

P Wave

Depolarization of the right and left atria.

QRS Complex

Depolarization of the right and left ventricles.

T Wave

Repolarization of the right and left ventricles.

P-R Interval

Time from the onset of atrial depolarization to the onset of ventricular depolarization.

Q-T Interval

Time from onset of ventricular depolarization to the end of ventricular repolarization.

R-R Interval

Time between two successive ventricular depolarizations.

P-R Segment

Time of impulse conduction from the AV node to the ventricular myocardium.

S-T Segment

Period of time representing the early part of ventricular repolarization during which ventricles are more or less uniformly excited.

T-P Segment

Time from the end of ventricular repolarization to the onset of atrial depolarization.

Lead

Arrangement of two electrodes with respect to a third electrode.

Baroreceptor Reflexes

Heart rate adjustments made by systemic arterial and systemic venous pressure receptor reflexes in response to the cycling of intrathoracic pressure.

Larger Hearts in Athletes

Condition known as left ventricular hypertrophy.