12 LEAD EKG PRACTICE
EXAM
Question 1: What is the intrinsic �ring rate of the SA node?
Choices:
1) 20-40 bpm 2) 40-60 bpm 3) 60-100 bpm 4) 100-120 bpm
Correct Answer: 60-100 bpm
Explanation: The sinoatrial (SA) node is the primary pacemaker of the heart with an intrinsic �ring rate of 60-100 beats per minute.Page 1
Question 2: Which component of the conduction system delays the electrical
impulse to allow for ventricular �lling?
Choices:
1) SA node 2) AV node 3) Bundle of His 4) Purkinje �bers
Correct Answer: AV node
Explanation: The atrioventricular (AV) node delays the electrical impulse (represented by the PR segment) to allow the atria to contract and �ll the ventricles before ventricular systole.
Question 3: Where is the correct placement for lead V1?
Choices:
1) Fourth intercostal space, right sternal border 2) Fourth intercostal space, left sternal border 3) Fifth intercostal space, midclavicular line 4) Fifth intercostal space, anterior axillary line
Correct Answer: Fourth intercostal space, right sternal border
Explanation: Lead V1 is placed at the 4th intercostal space at the right sternal border.Page 2
Question 4: Where is the correct placement for lead V4?
Choices:
1) Fourth intercostal space, left sternal border 2) Fifth intercostal space, midclavicular line 3) Fifth intercostal space, midaxillary line 4) Between V2 and V4
Correct Answer: Fifth intercostal space, midclavicular line
Explanation: Lead V4 is placed at the 5th intercostal space in the midclavicular line.
Question 5: Which leads make up the bipolar limb leads?
Choices:
1) I, II, and III 2) aVR, aVL, and aVF 3) V1, V2, and V3 4) V4, V5, and V6
Correct Answer: I, II, and III
Explanation: Leads I, II, and III are the standard bipolar limb leads, forming Einthoven's triangle.Page 3