Electrophysiology and ECG Concepts

This set of flashcards covers key vocabulary and concepts related to electrophysiology and ECGs, including action potentials, conduction velocity, and various arrhythmias.

Electrophysiology

The study of electrical activity in the heart, particularly the cardiac cellular ion and voltage changes during depolarization and repolarization.

Action Potential (AP)

The electrical signal that propagates along cardiac cells, resulting in contraction and relaxation.

Conduction Velocity

The rate of action potential propagation through cardiac tissue, measured as distance over time.

Repolarization

The process of restoring the membrane potential to its resting state after depolarization.

Mean Electrical Vector

The average direction of electrical current flow in the heart, influencing the appearance of ECG waves.

P Wave

The part of the ECG that represents atrial depolarization.

QRS Complex

The portion of the ECG showing ventricular depolarization.

ST Segment

The section of the ECG corresponding to ventricular contraction and ejection; isoelectric line.

T Wave

The part of the ECG that represents ventricular repolarization.

Hyperkalemia

A condition characterized by elevated potassium levels in the blood, affecting action potential characteristics.

Sinoatrial Node (SA Node)

The natural pacemaker of the heart, initiating the electrical impulse for heartbeats.

Atrial Fibrillation

An irregular and often rapid heart rate caused by chaotic electrical impulses in the atria.

First-Degree AV Block

A conduction delay where the PR interval is prolonged to more than 0.20 seconds, but all impulses are still conducted.

Second-Degree AV Block (Mobitz Type I)

A conduction block where the PR interval progressively lengthens until a QRS complex is dropped.

Ventricular Tachycardia

A fast heart rate originating from the ventricles, typically greater than 100 beats per minute.

Resting Membrane Potential (Vm)

The voltage across the cell membrane of a cardiac cell at rest, influencing action potential amplitude and conduction velocity.

Post-Repolarization Refractoriness

A state during which cells are less excitable immediately after repolarization, affecting subsequent action potential characteristics.

Purkinje Fibers

Specialized cardiac fibers that conduct action potentials rapidly through the ventricles.

Conduction System

The network of specialized tissues in the heart that initiates and conducts electrical impulses.

Premature Ventricular Complex (PVC)

An early heartbeat originating from an ectopic focus in the ventricles, resulting in a widened QRS complex.