What is the major effect of calcium channel blockers on cardiac contractions
Increases the rate of cardiac contractions
Decreases the strength of cardiac contractions
Stabilizes the rhythm of cardiac contractions
Stabilizes the vasodilation during cardiac contractions
The Correct Answer is B
Calcium channel blockers (CCBs) are a class of medications that block the influx of calcium ions into cardiac and smooth muscle cells, leading to relaxation of these muscles and dilation of blood vessels.
In the heart, CCBs primarily affect the L-type calcium channels in the cardiac myocytes, which are responsible for the influx of calcium ions during the plateau phase of the cardiac action potential. By blocking these channels, CCBs decrease the amount of calcium that enters the cardiac myocytes, which in turn reduces the strength of cardiac contractions (i.e. contractility). 
This reduction in contractility can be beneficial in certain conditions where the heart is working too hard or experiencing insufficient blood flow, such as in hypertension, angina, or some forms of arrhythmia. By reducing the workload of the heart, CCBs can help to lower blood pressure, decrease oxygen demand, and improve blood flow to the heart.
While CCBs can also have effects on the rate and rhythm of cardiac contractions, these effects are generally less pronounced than the reduction in contractility. Some CCBs, such as verapamil and diltiazem, can slow the heart rate by blocking the L-type calcium channels in the sinoatrial (SA) and atrioventricular (AV) nodes, while others, such as nifedipine, have little effect on heart rate.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Modifiable risk factors for coronary artery disease (CAD) are those that can be changed or controlled to reduce the risk of developing CAD. These include high blood pressure, high cholesterol levels, smoking, physical inactivity, unhealthy diet, and obesity. High HDL (high-density lipoprotein) is actually a desirable factor, as it is known as the "good cholesterol" and helps to remove excess cholesterol from the body. Orthostatic hypotension, or a drop in blood pressure upon standing, is not considered a modifiable risk factor for CAD.
Correct Answer is D
Explanation
Sustained hypertension can lead to several complications, including damage to the blood vessels in the retina (retinopathy), increased risk of stroke, and damage to the kidneys (renal disease). Other potential complications include heart disease, peripheral arterial disease, and cognitive impairment. It is important to manage hypertension through lifestyle modifications and medication to prevent these complications.
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