Anatomy of the Conduction System
What structure initiates the electrical impulses in the heart?
The SA node (sinoatrial node), also known as the heart's natural pacemaker.
Source: American Heart Association - Overview of the Heart’s Electrical System
What does depolarization mean in cardiac conduction?
is the electrical activation of heart cells, leading to muscle contraction.
Source: Mayo Clinic - Heart Rhythm Overview.
What does the P wave on an ECG represent?
Atrial depolarization.
Source: Mayo Clinic - Understanding ECGs.
What is bradycardia?
A slow heart rate, typically below 60 beats per minute.
Source: Mayo Clinic - Slow Heart Rates.
What medication is commonly used to slow heart rate in tachycardia?
Beta-blockers.
Source: Mayo Clinic - Medication for Arrhythmias.
What is the function of the AV node in the conduction system?
It delays the electrical signal to allow the atria to contract before the ventricles.
Source: Mayo Clinic - Cardiac Conduction Pathways
What is repolarization?
It is the process where heart cells reset electrically after depolarization, preparing for the next contraction.
Source: American Heart Association - How the Heart Beats.
What does the QRS complex indicate on an ECG?
Ventricular depolarization.
Source: NIH - ECG Basics.
What is tachycardia?
A fast heart rate, typically above 100 beats per minute.
Source: NIH - Fast Heart Rates.
What device is implanted to regulate heart rhythm in bradycardia?
A pacemaker.
Source: NIH - Pacemaker Technology.
Which structure transmits electrical signals from the AV node to the Purkinje fibers?
The Bundle of His.
Source: NIH - Heart’s Electrical System.
What term describes the heart's ability to generate electrical impulses on its own?
Automaticity.
Source: Textbook: Cardiac Electrophysiology: From Cell to Bedside.
What does a prolonged PR interval signify?
A first-degree heart block.
Source: Mayo Clinic - Arrhythmias Explained.
What is a third-degree heart block?
A complete failure of electrical conduction from the atria to the ventricles.
Source: American Heart Association - Heart Block Overview.
What is the purpose of catheter ablation?
To destroy small areas of heart tissue causing abnormal electrical signals.
Source: American Heart Association - Ablation Overview.
Where are the Purkinje fibers located, and what is their function?
They are located in the ventricular walls and conduct impulses that cause ventricular contraction.
Source: Textbook: Cardiac Electrophysiology: From Cell to Bedside.
What is the refractory period?
A phase during which cardiac cells cannot respond to a new electrical impulse.
Source: NIH - Cardiac Cycle Basics.
What does the T wave represent on an ECG?
Ventricular repolarization.
Source: American Heart Association - ECG Interpretation Guide.
What condition occurs when rapid electrical impulses in the atria cause inefficient contractions?
Atrial fibrillation.
Source: NIH - Atrial Fibrillation Basics.
What is an Implantable Cardioverter Defibrillator (ICD)?
A device that delivers shocks to correct dangerous arrhythmias.
Source: Mayo Clinic - ICD Basics.
What is the pathway of electrical conduction through the heart?
SA node → AV node → Bundle of His → Bundle branches → Purkinje fibers.
Source: NIH - Understanding Cardiac Conduction.
What is the significance of the action potential in cardiac cells?
It describes the electrical changes that occur in heart cells during depolarization and repolarization.
Source: Textbook: Cardiac Electrophysiology.
What is a common finding on an ECG in a patient with atrial fibrillation?
The absence of distinct P waves and an irregularly irregular rhythm.
What is ventricular fibrillation, and why is it life-threatening?
A chaotic, disorganized rhythm in the ventricles that leads to cardiac arrest if not treated.
Source: Mayo Clinic - Dangerous Heart Rhythms.
What is the procedure called that uses synchronized electrical shocks to restore normal rhythm?
Cardioversion.
Source: NIH - Cardioversion Explained.