Class IV antidysrhythmics or calcium channel blockers have what action on the cardiovascular system?
Increase blood vessel spasm.
Decrease flow of calcium ions thus decreasing heart rate and contractions.
Decrease refractory period.
Increase heart rate.
The Correct Answer is B
Class IV antidysrhythmics or calcium channel blockers decrease the flow of calcium ions into cardiac and vascular smooth muscle cells, thus decreasing heart rate and contractions. By reducing the calcium influx, they also decrease the slope of phase 0 and 4 and prolong phase 2 of the cardiac action potential. This results in vasodilation, reduced myocardial oxygen demand, and decreased conduction through the AV node.
Choice A is wrong because calcium channel blockers do not increase blood vessel spasm, but rather cause vasodilation.
Choice C is wrong because calcium channel blockers do not decrease refractory period, but rather prolong it by extending phase 2 of the cardiac action potential.
Choice D is wrong because calcium channel blockers do not increase heart rate, but rather decrease it by slowing down the pacemaker activity and AV nodal conduction.
Normal ranges for heart rate are 60 to 100 beats per minute, and for blood pressure are 120/80 mmHg or lower.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
The correct answer is Choice D: Headache.
Choice A rationale: Nausea is not a common adverse effect of sublingual nitroglycerin. Nausea may occur in some patients, but it is usually mild and transient.Nausea may be related to the vasodilatory effects of nitroglycerin, which can cause hypotension and reflex tachycardia1. Nausea may also be caused by other factors, such as anxiety, stress, or food intolerance.Nausea is not a specific indicator of nitroglycerin toxicity or overdose2.
Choice B rationale: Bradycardia is not a common adverse effect of sublingual nitroglycerin. Bradycardia is a slow heart rate, usually defined as less than 60 beats per minute.Bradycardia may occur in some patients who take nitroglycerin, especially in combination with other drugs that affect the heart rate, such as beta-blockers, calcium channel blockers, or digoxin3. Bradycardia may also be caused by other factors, such as vagal stimulation, hypothyroidism, or electrolyte imbalance.Bradycardia is not a specific indicator of nitroglycerin toxicity or overdose2.
Choice C rationale: Hypertension is not a common adverse effect of sublingual nitroglycerin. Hypertension is a high blood pressure, usually defined as more than 140/90 mmHg.Hypertension may occur in some patients who take nitroglycerin, especially in those who have a history of hypertension, renal impairment, or volume overload4. Hypertension may also be caused by other factors, such as stress, pain, or caffeine intake.Hypertension is not a specific indicator of nitroglycerin toxicity or overdose2.
Choice D rationale: Headache is a common adverse effect of sublingual nitroglycerin.Headache may occur in up to 80% of patients who take nitroglycerin, especially during the first few days of therapy or after an increase in dose5. Headache may be related to the vasodilatory effects of nitroglycerin, which can cause cerebral vasodilation and increased intracranial pressure. Headache may also be caused by other factors, such as dehydration, sinusitis, or migraine. Headache is usually mild to moderate in intensity and can be relieved by analgesics, such as acetaminophen or aspirin.Headache is not a specific indicator of nitroglycerin toxicity or overdose
Correct Answer is C
Explanation
LDL cholesterol is sometimes called “bad” cholesterol because it can build up on the walls of the blood vessels and cause health problems, such as heart disease and stroke.High levels of LDL cholesterol raise your risk for cardiovascular disease. Therefore, decreasing LDL cholesterol levels can lower your risk and improve your health.
Choice A is wrong because increasing LDL cholesterol levels would have the opposite effect of decreasing them.It would increase your risk for cardiovascular disease and plaque buildup in your arteries.
Choice B is wrong because increasing HDL cholesterol levels is not enough to decrease the risk of cardiovascular disease.HDL cholesterol is sometimes called “good” cholesterol because it can move LDL cholesterol from the blood to the liver, where it is broken down and removed from the body.
However, HDL cholesterol levels alone are not a good indicator of your cardiovascular health.You also need to consider your total cholesterol, LDL cholesterol and triglyceride levels.
Choice D is wrong because decreasing HDL cholesterol levels would also increase your risk for cardiovascular disease.HDL cholesterol helps to lower LDL cholesterol levels and protect your blood vessels from plaque buildup.
Therefore, decreasing HDL cholesterol levels would reduce this protective effect and make you more vulnerable to heart disease and stroke.
The ideal ranges for cholesterol levels are as follows:
• Total cholesterol: below 200 mg/dL
• LDL cholesterol: less than 100 mg/dL
• HDL cholesterol: above 40 mg/dL for men and above 50 mg/dL for women
You can lower your LDL cholesterol levels and increase your HDL cholesterol levels by making healthy lifestyle changes, such as eating a balanced diet, exercising regularly, quitting smoking, managing stress and taking medication if prescribed by your doctor.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.