Arrhythmia By Zainab Azal: Cardiac Conduction and Electrophysiology Overview

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What structure may take over as the pacemaker in case both the sinus node and AV node fail to generate depolarizations at a rate faster than 30-40 per minute?

Atrioventricular (AV) node

Ventricles (correct)

Coronary arteries

His bundle

Which segment of the electrocardiogram reflects the period of zero potential between ventricular depolarization and repolarization?

PR interval

QRS complex

P wave

ST segment (correct)

What is the main function of the QRS complex in the electrocardiogram?

Show beginning of systole and ventricular contraction (correct)

Represent ventricular depolarization

Reflect atrial repolarization

Indicate atrial contraction

Which part of the heart's conducting system may assume the role of pacemaker if the sinus rate becomes slow?

AV node Signup and view all the answers

Which structure is responsible for generating the P wave on the surface electrocardiogram?

SA node Signup and view all the answers

What does the PR interval in an electrocardiogram reflect?

Conduction through the AV node Signup and view all the answers

What is the main cause of mechanical activity in the heart?

Electrical activity of the heart Signup and view all the answers

Which part of the heart is known as the dominant pacemaker?

Sinoatrial (SA) node Signup and view all the answers

What is the normal rate of electrical impulses generated by the SA node?

60-100 bpm Signup and view all the answers

Which part of the heart provides a conduction pathway between the atria and ventricles?

Atrioventricular (AV) node Signup and view all the answers

What is the purpose of the delay provided by conduction through the AV node?

To allow time for ventricular contraction Signup and view all the answers

Why does ventricular activation occur synchronously in less than 0.1 seconds?

To ensure hemodynamically effective contraction Signup and view all the answers

What is the impact of circulating drugs, such as antiarrhythmics, on the heart regarding arrhythmias?

They can predispose the heart to arrhythmias. Signup and view all the answers

Which of the following is NOT a risk factor for developing arrhythmias?

Hyperglycemia Signup and view all the answers

In normal heart rhythm pathways, which structure has the highest firing rate and determines the heart rate?

Sinus node Signup and view all the answers

What can cause the development of pacemaker activity in cells outside of the cardiac conduction system?

Abnormal automaticity Signup and view all the answers

Which condition does NOT predispose the heart to arrhythmias according to the text?

Hypoglycemia Signup and view all the answers

What characterizes abnormal impulse propagation as mentioned in the text?

'Re-entry' causing clinically important arrhythmias Signup and view all the answers