#1
Which part of the heart is responsible for initiating the electrical impulses in the cardiac cycle?
Atria
Ventricles
Sinoatrial (SA) node
Atrioventricular (AV) node
#2
What is the main purpose of the QRS complex in an ECG waveform?
Atrial repolarization
Ventricular depolarization
Ventricular repolarization
Atrial depolarization
#3
In which ECG lead is the R-wave amplitude typically the greatest?
Lead I
Lead II
Lead III
Lead V4
#4
What does the term 'PR interval' measure on an ECG?
Time from the start of atrial depolarization to the start of ventricular depolarization
Time from the start of atrial depolarization to the end of ventricular repolarization
Time from the start of ventricular depolarization to the end of ventricular repolarization
Time from the start of atrial depolarization to the end of atrial repolarization
#5
What is the significance of the ST segment in an ECG waveform?
Atrial depolarization
Ventricular depolarization
Represents the time between ventricular depolarization and repolarization
Atrial repolarization
#6
What does the P-wave represent in an ECG waveform?
Atrial depolarization
Ventricular depolarization
Atrial repolarization
Ventricular repolarization
#7
Which lead in a 12-lead ECG is commonly associated with the lateral wall of the heart?
Lead I
Lead II
Lead V1
Lead V6
#8
Which electrolyte imbalance is associated with a prolonged QT interval on an ECG?
Hyperkalemia
Hypokalemia
Hypercalcemia
Hypocalcemia
#9
What does the term 'ST-segment elevation' typically indicate in an ECG?
Myocardial ischemia
Myocardial infarction
Bundle branch block
Atrial fibrillation
#10
What is the approximate normal heart rate range for adults at rest?
60-90 beats per minute
90-120 beats per minute
120-150 beats per minute
150-180 beats per minute
#11
Which condition is characterized by the absence of P-waves in an ECG, with irregular and chaotic ventricular activity?
Atrial fibrillation
Atrial flutter
Ventricular tachycardia
Ventricular fibrillation
#12
What is the normal duration of the PR interval in milliseconds?
Less than 120 ms
120-200 ms
200-300 ms
More than 300 ms
#13
In a 12-lead ECG, which leads are considered precordial leads?
Leads I, II, III
Leads aVR, aVL, aVF
Leads V1-V6
Leads I, aVR, V1-V6
#14
Which lead is commonly used to assess the heart's electrical axis in an ECG?
Lead I
Lead II
Lead aVF
Lead III
#15
What is the primary purpose of the T-wave in an ECG waveform?
Atrial depolarization
Ventricular depolarization
Ventricular repolarization
Atrial repolarization
#16
What does the term 'bundle branch block' refer to in an ECG?
Delayed or blocked conduction in the bundle branches
Normal conduction in the bundle branches
Atrial depolarization
Ventricular repolarization
#17
Which segment of the ECG represents the time between ventricular depolarization and repolarization?
P-wave
QRS complex
ST segment
T-wave