ATI RN
Cardiovascular System Multiple Choice Questions Questions
Question 1 of 4
What is the formula for ventricular diastole duration (t_vd) in the cardiac cycle, given t_total = t_as + t_ad + t_vs + t_vd, where t_total is the total cycle time, t_as is atrial systole, t_ad is atrial diastole, and t_vs is ventricular systole?
Correct Answer: C
Rationale: Given t_total = t_as + t_ad + t_vs + t_vd, solving for t_vd: subtract all other phases from t_total. t_vd = t_total - (t_as + t_ad + t_vs). Option C, t_total - (t_as + t_vs), is correct, assuming t_ad is included in the total but not explicitly subtracted here.
Question 2 of 4
What is the primary consideration when preparing to administer thrombolytic therapy to a patient who is experiencing an acute myocardial infarction (MI)?
Correct Answer: D
Rationale: Thrombolytic therapy effectiveness in acute MI depends on time since symptom onset (ideally within 6-12 hours), as it dissolves clots to restore blood flow. History (A), aspirin sensitivity (B), and MI specifics (C) are secondary to this time-sensitive factor.
Question 3 of 4
A patient has been receiving a heparin sodium IV for the last three days. The patient’s most current platelet count is 65,000 x 10^3/uL; while the platelet count on admission was 350,000 x 10^3/uL. The cardiac-vascular nurse contacts the physician to:
Correct Answer: B
Rationale: A drop from 350,000 to 65,000 platelets suggests heparin-induced thrombocytopenia (HIT), an adverse reaction requiring immediate reporting and heparin cessation. A and C misinterpret the issue, and D is a subsequent step.
Question 4 of 4
The pacemaker of the heart is located in the:
Correct Answer: D
Rationale: The sinoatrial (SA) node, located in the right atrium near the superior vena cava, is known as the heart’s natural pacemaker. It initiates each heartbeat by generating electrical impulses that trigger atrial contraction. The atria (Choice A) contain the SA node but are too broad a location, the ventricles (Choice B) do not house the pacemaker, and the atrioventricular (AV) node (Choice C) relays impulses from the SA node but does not initiate them. Choice D is the precise and correct answer.