Cardiac Electrophysiology Quizzes: Master Heart Electrical Activity

Question 1

Which of the following ion concentration gradients primarily contribute to the resting membrane potential in cardiac cells?

Accepted Answer

Potassium (K+) and Sodium (Na+)

Answer

Sodium (Na+) and Chloride (Cl-)

Answer

Chloride (Cl-) and Calcium (Ca2+)

Answer

Potassium (K+) and Chloride (Cl-)

Question 2

Which ion is primarily responsible for cardiac action potential repolarization?

Accepted Answer

Potassium

Answer

Sodium

Answer

Calcium

Answer

Chloride

Question 3

Which of the following is not an arrhythmia type?

Accepted Answer

Hypertension

Answer

Bradycardia

Answer

Tachycardia

Answer

Ventricular fibrillation

Question 4

Which electrocardiographic wave represents ventricular depolarization?

Accepted Answer

QRS complex

Answer

P wave

Answer

T wave

Answer

U wave

Question 5

Which drug is commonly used to treat arrhythmias by blocking sodium channels in the heart?

Accepted Answer

Lidocaine

Answer

Atenolol

Answer

Digoxin

Answer

Amiodarone

Question 6

Which electrocardiogram interval represents the time from the QRS complex onset to the T wave end?

Accepted Answer

QT interval

Answer

PR interval

Answer

RR interval

Answer

ST segment

Question 7

During the action potential, the rapid influx of sodium ions into the cell occurs during which phase?

Accepted Answer

Phase 0 (Depolarization)

Answer

Phase 1 (Early Repolarization)

Answer

Phase 2 (Plateau)

Answer

Phase 3 (Repolarization)

Question 8

Which of the following electrocardiography (ECG) waves represents the electrical activity associated with ventricular depolarization?

Accepted Answer

QRS complex

Answer

P wave

Answer

T wave

Answer

U wave

Question 9

Atrial fibrillation (AFib) is characterized by:

Accepted Answer

Rapid and irregular atrial contractions

Answer

Slow and regular ventricular contractions

Answer

Normal sinus rhythm

Answer

Complete heart block

Question 10

Which of the following ion channels is primarily responsible for maintaining the plateau phase of the ventricular action potential?

Accepted Answer

L-type calcium channels

Answer

Fast sodium channels

Answer

Slow sodium channels

Answer

Potassium channels

Question 11

The refractory period refers to the period when:

Accepted Answer

The cell is not excitable

Answer

The cell is excitable

Answer

The cell is partially excitable

Answer

The cell is hyperpolarized

Question 12

Which of the following drugs is commonly used to treat hypertension by blocking L-type calcium channels?

Accepted Answer

Verapamil

Answer

Atenolol

Answer

Digoxin

Answer

Warfarin

Question 13

On an ECG, the QT interval represents:

Accepted Answer

Ventricular depolarization and repolarization

Answer

Atrial depolarization and ventricular repolarization

Answer

Ventricular depolarization and atrial repolarization

Answer

Atrial depolarization and repolarization

Question 14

Ventricular tachycardia (VT) is defined as:

Accepted Answer

A rapid heart rate originating from the ventricles

Answer

A slow heart rate originating from the atria

Answer

An irregular heart rate originating from the atrioventricular node

Answer

A heart rate below 60 beats per minute

Question 15

Match the phases of the cardiac action potential with the predominant ionic currents that shape them:

Accepted Answer

Phase 0: Depolarization - Influx of sodium ions

Accepted Answer

Phase 1: Repolarization - Transient outward potassium current

Accepted Answer

Phase 2: Plateau - Influx of calcium ions

Accepted Answer

Phase 3: Repolarization - Outward potassium current

Question 16

Which ion channel is primarily responsible for the rapid depolarization phase of the cardiac action potential?

Accepted Answer

Fast sodium channel (Nav1.5)

Answer

L-type calcium channel (Cav1.2)

Answer

Slow sodium channel (Nav1.9)

Question 17

The main determinant of the plateau phase of the cardiac action potential is the:

Accepted Answer

L-type calcium current

Answer

Sodium-calcium exchanger current

Answer

Transient outward potassium current

Answer

Hyperpolarization-activated current

Question 18

Which electrocardiogram (ECG) lead provides the optimal view of electrical activity in the inferior wall of the heart?

Accepted Answer

Lead II

Answer

Lead I

Answer

Lead V1

Answer

Lead aVR

Question 19

The characteristic ECG finding associated with atrial fibrillation is:

Accepted Answer

Irregularly irregular P waves

Answer

ST-segment elevation in multiple leads

Answer

Wide QRS complexes with a heart rate less than 60 bpm

Answer

Regular P waves with a PR interval of less than 120 ms

Question 20

Which ion channel blocker is commonly used to treat ventricular arrhythmias by prolonging the action potential duration?

Accepted Answer

Amiodarone

Answer

Verapamil

Answer

Atropine

Question 21

The primary mechanism by which the vagus nerve exerts a negative chronotropic effect on the heart is through:

Accepted Answer

Activation of muscarinic acetylcholine receptors

Answer

Enhancement of L-type calcium current

Answer

Blockade of beta-adrenergic receptors

Answer

Inhibition of sodium-calcium exchanger

Question 22

Which of the following drugs is contraindicated in patients with severe bradycardia?

Accepted Answer

Beta-blockers

Answer

Digitalis

Answer

Amiodarone

Answer

Calcium channel blockers

Question 23

The electrical delay between the atria and ventricles is known as the:

Accepted Answer

PR interval

Answer

QT interval

Answer

ST segment

Question 24

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

Accepted Answer

Regular exercise

Answer

Hypertension

Answer

Coronary artery disease

Answer

Diabetes