#1
Which chamber of the heart initiates the electrical impulses for the cardiac cycle?
Right atrium
Left atrium
Right ventricle
Left ventricle
#2
What does the QRS complex represent in an electrocardiogram (ECG or EKG)?
Atrial depolarization
Ventricular depolarization
Atrial repolarization
Ventricular repolarization
#3
What is the purpose of the T-wave in an electrocardiogram (ECG or EKG)?
Atrial depolarization
Ventricular depolarization
Atrial repolarization
Ventricular repolarization
#4
What does the term 'PR interval' measure on an electrocardiogram (ECG)?
Time taken for atrial depolarization
Time taken for ventricular depolarization
Time from atrial depolarization to ventricular depolarization
Time for ventricular repolarization
#5
What does the term 'cardiac axis' refer to in an electrocardiogram (ECG)?
The rate of cardiac contraction
The orientation of the heart within the chest
The strength of the cardiac impulse
The time duration of the cardiac cycle
#6
What does the P-wave represent in an electrocardiogram (ECG or EKG)?
Atrial depolarization
Ventricular depolarization
Atrial repolarization
Ventricular repolarization
#7
Which structure is known as the 'natural pacemaker' of the heart?
Atrioventricular (AV) node
Bundle of His
Sinoatrial (SA) node
Purkinje fibers
#8
In which phase of the cardiac cycle does ventricular systole occur?
Isovolumetric contraction
Rapid ejection
Isovolumetric relaxation
Atrial systole
#9
Which electrolyte imbalance is associated with a prolonged QT interval on an ECG?
Hyperkalemia
Hypokalemia
Hypercalcemia
Hypocalcemia
#10
During which phase of the cardiac cycle does blood fill the ventricles?
Isovolumetric contraction
Rapid ejection
Isovolumetric relaxation
Ventricular diastole
#11
What is the normal duration of the PR interval in an ECG?
0.06 to 0.12 seconds
0.12 to 0.20 seconds
0.20 to 0.30 seconds
0.30 to 0.40 seconds
#12
Which ECG lead placement is commonly used to assess the lateral wall of the heart?
Lead I
Lead II
Lead III
Lead aVL
#13
What is the primary function of the Bundle of His in the cardiac conduction system?
Delaying the impulse at the AV node
Initiating the impulse at the SA node
Conducting the impulse to the Purkinje fibers
Coordinating atrial contraction
#14
Which leads in an ECG represent the inferior wall of the heart?
Leads I, II, and III
Leads aVL, aVR, and aVF
Leads V1 to V6
Leads II, III, and aVF
#15
What is the significance of the ST segment on an ECG?
Represents atrial repolarization
Indicates ventricular depolarization
Reflects ventricular repolarization
Marks the early phase of ventricular systole