MSN Exam for Angina Pectoris

EXPLANATION

 

✔Correct answer:

A moderate amount of 10 to 15 grams of a simple carbohydrate. In cases of hypoglycemia, especially for individuals with diabetes, it is crucial to promptly increase the blood glucose level to within a safe range to prevent further complications. The recommended initial treatment for mild hypoglycemia (blood glucose less than 70 mg/dL) is to consume 10 to 15 grams of a simple carbohydrate. This amount of carbohydrate is sufficient to raise blood glucose levels without causing a significant overshoot, leading to hyperglycemia. Simple carbohydrates are preferred in this scenario because they are absorbed quickly, leading to a rapid increase in blood glucose levels. After taking the carbohydrate, it's advisable to recheck blood glucose levels after 15 minutes and repeat the treatment if hypoglycemia persists.

Imagine your body as a car and glucose as the fuel. When the fuel (glucose) levels get too low, the car (your body) starts sputtering and cannot function properly. Taking 10 to 15 grams of a simple carbohydrate is like putting a moderate amount of fuel into the car quickly to get it running smoothly again without the risk of overfilling it (which in the body's case, would be overshooting to hyperglycemia).

Glucose is the primary energy source for the body's cells. In hypoglycemia, the blood glucose level drops below the normal range, which can impair brain function and lead to symptoms like confusion, sweating, and in severe cases, loss of consciousness or seizures. The brain is particularly sensitive to low blood glucose levels as it relies almost exclusively on glucose for energy. The recommended 10 to 15 grams of a simple carbohydrate provides a quick source of glucose to the bloodstream, ensuring that the brain and other organs receive the energy they need to function correctly.

 

✘Incorrect answer options:

A small amount of 2 to 5 grams of a simple carbohydrate. This amount is insufficient to adequately raise blood glucose levels in a situation of mild hypoglycemia. It may not provide enough glucose to alleviate symptoms and normalize blood glucose levels.

A larger dose of 18 to 20 grams of a simple carbohydrate. While this amount may effectively raise blood glucose levels, it may also lead to an overcorrection, causing blood glucose levels to become too high (hyperglycemia). This can lead to a cycle of high and low blood sugars, which is especially harmful in the long term for individuals with diabetes.

A very large dose of 25 to 30 grams of a simple carbohydrate. This amount is likely to cause a significant overshoot in blood glucose levels, leading to hyperglycemia. Consistently high blood glucose levels can lead to long-term complications of diabetes, including cardiovascular disease, kidney damage, and nerve damage.

 

References

• American Diabetes Association. (2021). 6. Glycemic Targets: Standards of Medical Care in Diabetes—2021. Diabetes Care, 44(Supplement 1), S73–S84.
• McPherson, R. A., & Pincus, M. R. (2021). Henry's Clinical Diagnosis and Management by Laboratory Methods. Elsevier Health Sciences.

EXPLANATION

 

✔Correct answer:

Increased levels of PKG leading to the relaxation of smooth muscle cells. Organic nitrates, such as nitroglycerin, are used in the treatment of angina due to their ability to relax smooth muscle cells, particularly in blood vessels. The mechanism by which they accomplish this involves a series of biochemical reactions that ultimately increase the levels of cyclic guanosine monophosphate (cGMP). This increase in cGMP activates protein kinase G (PKG), an enzyme that phosphorylates (adds a phosphate group to) various proteins within the smooth muscle cell. The phosphorylation of these proteins leads to a reduction in intracellular calcium levels and a series of interactions that cause the smooth muscle cells to relax. This relaxation of smooth muscle cells, especially in the veins and arteries, leads to vasodilation, reducing the preload and afterload on the heart, and ultimately decreasing the cardiac workload.

Imagine the smooth muscle cells in blood vessels as a clenched fist. Organic nitrates work at the cellular level much like a message that tells the fist to relax and open up. This message is delivered through a series of steps, with PKG acting like a key player in passing the message. When the message is received, the fist (smooth muscle cells) unclenches (relaxes), making the space inside bigger (vasodilation), and allowing for easier blood flow.

The relaxation of vascular smooth muscle cells decreases the overall vascular tone, leading to dilation of both veins and arteries. Venous dilation predominantly leads to a decrease in preload (the volume of blood returning to the heart), whereas arterial dilation reduces systemic vascular resistance and afterload (the resistance the heart must overcome to pump blood). The reduction in preload and afterload decreases the heart's oxygen demand, which is beneficial in conditions like angina, where the heart's oxygen supply is compromised.

 

✘Incorrect answer options:

Increased levels of PKG leading to the relaxation of large veins and arteries. This option is not precise at the cellular level. While PKG does play a role in the relaxation process, the statement does not specify that the action is on the smooth muscle cells, which is a crucial part of the mechanism.

Decreased levels of PKG resulting in the relaxation of smooth muscle cells. This statement is incorrect as the relaxation of smooth muscle cells is associated with increased, not decreased, levels of PKG.

Decreased levels of PKG resulting in the contraction of smooth muscle cells. This option is incorrect as it contradicts the actual mechanism of action. Increased (not decreased) levels of PKG are involved in the relaxation (not contraction) of smooth muscle cells.

 

References

• Berne, R. M., Levy, M. N., Koeppen, B. M., & Stanton, B. A. (2004). Physiology, 5th Ed. Mosby, Inc.
• Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12th Edition. Brunton, L., Chabner, B., & Knollmann, B. (2011).

EXPLANATION

 

✔Correct answer:

Taking a shower. For a patient with stable angina, activities that suddenly increase the heart's workload and oxygen demand or decrease oxygen supply can trigger an angina episode. Taking a shower, particularly a hot shower, can be such a trigger. The heat from the water can cause vasodilation (widening of blood vessels), which in turn can lower blood pressure. To maintain blood pressure and blood flow, the heart rate increases, thereby increasing the heart's workload and oxygen demand. In someone with coronary artery disease, this increased demand may not be met due to narrowed arteries, potentially leading to an angina episode.

Imagine the heart as a pump in a heating system and the blood vessels as pipes. Taking a hot shower is like suddenly opening several faucets (vasodilation) in the system. The pump (heart) needs to work harder to maintain the same water pressure (blood pressure) in the system. If the pump already has some issues (narrowed coronary arteries), this extra work could be too much, causing the system to falter (angina episode).

Stable angina is typically triggered by activities that increase the demand for oxygen by the heart muscle, such as physical exertion or emotional stress. When the coronary arteries are narrowed due to atherosclerosis, they cannot supply enough blood to meet the increased oxygen demand. Activities like taking a hot shower can induce a rapid change in heart rate and blood pressure, challenging the compromised cardiovascular system and potentially triggering angina.

 

✘Incorrect answer options:

• Engaging in a quiet activity like reading a book.
• Being in a restful state like sleep.
• Leisurely watching television.

These activities are generally not associated with an increased risk of triggering angina in patients with stable angina because they do not significantly increase the heart's workload or oxygen demand. They are considered low-risk activities and are usually safe for individuals with stable angina unless otherwise advised by a healthcare professional.

 

References

• Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Saunders Elsevier.
• American Heart Association. (2021). Angina (Chest Pain). [online] Available at: https://www.heart.org/en/health-topics/heart-attack/angina-chest-pain.

EXPLANATION

 

✔Correct answer:

Right-sided heart failure. The symptoms Sarah is presenting with—weight gain, nausea, and decreased urine output—are indicative of fluid retention and systemic congestion, which are classic signs of right-sided heart failure. In right-sided heart failure, the right ventricle is unable to pump blood effectively into the pulmonary circulation, leading to a backlog of blood in the systemic circulation. This causes fluid to accumulate in the body tissues, particularly in the extremities and abdominal organs, a condition known as systemic or peripheral edema. Weight gain is a common manifestation due to fluid accumulation. Decreased urine output occurs because the kidneys receive less blood flow, leading to reduced urine formation. Nausea can result from congestion and swelling of the liver and gastrointestinal tract, as these organs become congested with fluid.

Think of a garden watering system: If the pump (right heart) cannot push water (blood) forward efficiently, the water starts to back up in the supply lines (veins). The hoses (veins) swell with the excess water, and the garden beds (organs and tissues) get waterlogged (congested with fluid), which is not ideal for the plants (organs) or the system as a whole.

In right-sided heart failure, the right ventricle is weakened and cannot pump blood into the pulmonary artery effectively. This leads to a buildup of pressure in the venous system, causing fluid to leak from the capillaries into the surrounding tissues, resulting in edema. The kidneys, sensing reduced blood flow, may retain water and sodium, which further contributes to fluid retention and decreased urine output.

 

✘Incorrect answer options:

Cardiomyopathy. Cardiomyopathy refers to diseases of the heart muscle and can lead to heart failure. However, the symptoms provided are not specific enough to diagnose cardiomyopathy without further evidence of impaired heart muscle function.

Angina pectoris. Angina pectoris is chest pain caused by reduced blood flow to the heart muscle. While it is a symptom of coronary artery disease, it does not directly cause weight gain, nausea, or decreased urine output.

Left-sided heart failure. Left-sided heart failure, involving the left ventricle, typically presents with pulmonary symptoms due to backup of blood into the lungs. This would more likely lead to shortness of breath, coughing, and wheezing rather than the systemic symptoms of fluid retention seen in right-sided heart failure.

 

References

• Jarvis, C. (2019). Physical Examination and Health Assessment. Elsevier Health Sciences.
• Porth, C. M., & Matfin, G. (2009). Pathophysiology: Concepts of Altered Health States. Lippincott Williams & Wilkins.

EXPLANATION

 

✔Correct answer:

Reduction in oxygen consumption; redirection of coronary blood flow to ischemic areas; alleviation of coronary spasms; improved perfusion. Organic nitrates are a cornerstone in the management of angina pectoris. They work primarily by relaxing vascular smooth muscle, which leads to several beneficial effects for patients with angina:

1. Reduction in oxygen consumption: Nitrates cause vasodilation, which decreases preload (the volume of blood returning to the heart) and afterload (the resistance against which the heart has to pump). This reduces the workload of the heart and, consequently, the heart's oxygen demand.
2. Redirection of coronary blood flow to ischemic areas: Nitrates induce vasodilation in the coronary arteries, improving blood flow to ischemic areas of the heart muscle.
3. Alleviation of coronary spasms: Nitrates are effective in relaxing the smooth muscle in the coronary arteries, preventing or alleviating coronary artery spasms, which can cause angina.
4. Improved perfusion: By dilating blood vessels and reducing the heart's workload, nitrates improve blood flow and perfusion throughout the body, including to the heart muscle itself.

Imagine the heart as a water pump in a garden and the coronary arteries as hoses delivering water to the pump itself. Organic nitrates are like adding a pressure regulator and a water softener to the system: they reduce the overall pressure the pump needs to work against (lower oxygen consumption) and ensure that the water (blood) can flow freely through the hoses (coronary arteries), especially to the areas of the garden (heart muscle) that are dry and need water the most (ischemic areas).

The primary goal in treating angina is to balance the oxygen supply and demand of the heart muscle, ensuring that the myocardium receives sufficient oxygen to function without pain. Organic nitrates achieve this by decreasing the cardiac workload (thereby reducing oxygen demand) and increasing blood flow to the myocardium (thereby increasing oxygen supply), which is particularly important in areas with compromised blood flow.

 

✘Incorrect answer options:

Elevation in oxygen consumption; redirection of coronary blood flow to areas of infarction; alleviation of coronary spasms; improved perfusion to other organs.

and

Reduction in oxygen consumption; redirection of coronary blood flow to areas of infarction; alleviation of coronary spasms; improved perfusion. These options incorrectly suggest an elevation in oxygen consumption or redirection of blood flow to areas of infarction. Nitrates work to reduce oxygen consumption and direct blood flow to ischemic (oxygen-starved) areas, not infarcted (dead tissue) areas.

Elevation in oxygen consumption; redirection of coronary blood flow to non-ischemic areas; no relief from coronary spasms; no improvement in perfusion. This option is incorrect as it suggests elevation in oxygen consumption and no relief from coronary spasms or improvement in perfusion, which contradicts the therapeutic action of nitrates.

 

References

• Goodman & Gilman's The Pharmacological Basis of Therapeutics. McGraw-Hill Education.
• Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Elsevier Health Sciences.

EXPLANATION

 

✔Correct answer:

On a non-hairy part of the body. For optimal percutaneous (through the skin) absorption of nitroglycerine ointment, it is crucial to apply it to a non-hairy part of the body. Hair can impede the absorption of the medication through the skin by trapping the ointment and preventing it from making direct contact with the skin surface. In addition, applying the ointment to a non-hairy area ensures more even distribution and absorption of the medication, leading to more consistent therapeutic effects.

Think of applying fertilizer to a lawn. If you apply it to a patchy area with lots of debris or leaves, the fertilizer won't be absorbed as effectively by the grass. Similarly, for the ointment to be absorbed effectively by the skin, it needs a clear, unobstructed area — hence, a non-hairy part of the body is preferred.

The skin acts as a barrier but also allows for the absorption of certain medications. The stratum corneum is the outermost layer of the skin and is the primary barrier to percutaneous absorption. Medications like nitroglycerine can be absorbed through the skin and enter systemic circulation, exerting their effects by relaxing vascular smooth muscle and dilating blood vessels. Ensuring optimal contact with the skin without interference from hair can maximize the drug's absorption and effectiveness.

 

✘Incorrect answer options:

Close to the heart. While it might seem intuitive to apply the medication close to the heart, the systemic absorption of nitroglycerine does not depend on proximity to the heart. Instead, it's more important to apply it to an area where the skin can absorb it effectively.

Over an area with a bony prominence. Areas with bony prominences are not ideal for ointment application because they are typically covered by thinner skin with less blood flow, potentially hindering absorption. Additionally, these areas are more prone to movement and friction, which can displace the ointment.

On a muscular region. Muscular regions are not necessarily the best choice for nitroglycerine ointment application. While these areas have good blood flow, they are also prone to movement and friction, which can displace the ointment and reduce the consistency of absorption. A flat, non-hairy area that remains relatively undisturbed during normal activities is preferred.

 

References

• Hadgraft, J., & Lane, M. E. (2015). Skin permeation: The years of enlightenment. International Journal of Pharmaceutics, 490(1-2), 3–12.
• Mutschler, E., Geisslinger, G., Kroemer, H. K., & Ruth, P. (2013). Mutschler Arzneimittelwirkungen. Pharmakologie - Klinische Pharmakologie - Toxikologie. Medpharm GmbH Scientific Publishers.

EXPLANATION

 

✔Correct answer:

Amplifying myocardial perfusion and lessening metabolic demands on the heart. The primary objectives of drug therapy for treating angina are to increase blood flow to the heart muscle (myocardial perfusion) and to decrease the heart's demand for oxygen. Increasing myocardial perfusion ensures that the heart muscle receives sufficient oxygen and nutrients, especially during times when the demand is increased (e.g., during physical exertion). Lessening the metabolic demands on the heart (the heart's workload) involves reducing factors such as heart rate, blood pressure, and myocardial contractility, all of which contribute to the heart's oxygen requirements. Medications used to treat angina, such as nitrates, beta-blockers, and calcium channel blockers, are aimed at achieving these goals, thereby preventing angina episodes and reducing the risk of more serious cardiac events.

Imagine the heart as a car engine and the blood supply as the fuel line. The goal of angina treatment is like making sure the engine doesn't work too hard (lessening metabolic demands) while also ensuring that it gets enough fuel (amplifying myocardial perfusion). If the engine works too hard without enough fuel, it could overheat or fail, just like the heart muscle might get damaged if it works too hard without enough blood supply.

The heart muscle requires a constant supply of oxygen-rich blood to function properly. Angina occurs when the blood supply to the heart muscle is insufficient to meet its oxygen demands, often due to narrowed coronary arteries (atherosclerosis). Drug therapy aims to address this imbalance by increasing the supply of oxygen-rich blood to the heart and/or by reducing the heart's demand for oxygen.

 

✘Incorrect answer options:

Enhancing cardiac output while reducing body fluid volume. This option is more relevant to the treatment of conditions like heart failure, where fluid overload and reduced cardiac output are typical concerns, rather than angina.

Lowering heart rate while increasing activation of the Renin-Angiotensin-Aldosterone System (RAAS). While lowering heart rate is a goal in angina treatment to reduce the heart's oxygen demand, activation of the RAAS is not a treatment goal in angina and is more associated with the long-term regulation of blood pressure and volume.

Elevating heart rate and diminishing myocardial perfusion. This option is the opposite of the treatment goals for angina. Increasing heart rate would increase the heart's oxygen demand, and diminishing myocardial perfusion would reduce the oxygen supply to the heart, both of which would exacerbate angina.

 

References

• Mann, D. L., Zipes, D. P., Libby, P., & Bonow, R. O. (2015). Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Elsevier Health Sciences.
• Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12th Edition. Brunton, L., Chabner, B., & Knollmann, B. (2011).

EXPLANATION

 

✔Correct answer:

Blood vessel widening and dilation of large veins, leading to reduced preload and decreased blood pressure. Organic nitrates, such as nitroglycerin, are a mainstay in the management of angina. Their primary effect is the relaxation and dilation of blood vessels, a process known as vasodilation. This action primarily reduces the preload, which is the volume of blood in the ventricles at the end of diastole (before contraction). When veins are dilated, they can hold more blood, and less blood returns to the heart, thereby reducing the preload. This reduction in preload decreases the ventricular volume and, consequently, the amount of work the heart has to perform, easing the symptoms of angina. Additionally, the dilation of arteries can reduce systemic vascular resistance, which can lower blood pressure.

Think of the cardiovascular system as a garden watering system. The heart is the pump, and the blood vessels are the hoses. Organic nitrates are like adjusting the hoses to a wider setting, allowing more space for the water to flow with less pressure. This means the pump (heart) doesn't have to work as hard to push water (blood) through, and the pressure within the system (blood pressure) is reduced.

In the setting of angina, the heart muscle demands more oxygen than the narrowed coronary arteries can supply. By reducing the preload (the volume of blood the heart must pump) and lowering the blood pressure (reducing the resistance against which the heart must pump), organic nitrates help to decrease the heart's workload and oxygen demand. This makes it easier for the heart to pump blood and reduces the likelihood of angina symptoms.

 

✘Incorrect answer options:

Blood vessel widening and dilation of large veins, leading to reduced after-load and decreased cardiac output. This option incorrectly states that organic nitrates decrease cardiac output. While they reduce the workload on the heart by decreasing preload and after-load, the primary effect is not on cardiac output but on easing the heart's workload.

Blood vessel widening and dilation of large veins, leading to reduced preload and decreased cardiac output. Similar to the above option, this choice incorrectly asserts a primary effect on cardiac output. The key effect of nitrates is to reduce preload and blood pressure, not necessarily to decrease cardiac output.

Blood vessel narrowing and constriction of large veins, leading to increased preload and elevated blood pressure. This statement is the opposite of what organic nitrates do. They dilate, not constrict, blood vessels, reducing, not increasing, preload and blood pressure.

 

References

• Klabunde, R. E. (2011). Cardiovascular Physiology Concepts. Lippincott Williams & Wilkins.
• Lilly, L. S. (2015). Pathophysiology of Heart Disease: A Collaborative Project of Medical Students and Faculty. Wolters Kluwer Health.

EXPLANATION

 

✔Correct answer:

A ruptured atherosclerotic plaque with thrombus formation, often causing complete occlusion. Unstable angina is a condition characterized by sudden, new-onset chest pain, or a change in the pattern of previously stable angina, often indicating that a heart attack might occur soon. The primary cause of unstable angina is the rupture of an atherosclerotic plaque in a coronary artery. When the plaque ruptures, it exposes the underlying tissue and lipids to the bloodstream, which triggers the clotting process and leads to the formation of a thrombus (blood clot). This thrombus can partially or completely block the blood flow through the coronary artery, reducing the oxygen supply to the heart muscle and leading to chest pain. Unlike stable angina, which typically occurs with exertion and resolves with rest, the symptoms of unstable angina are unpredictable and can occur at rest.

Imagine a pipe (coronary artery) carrying water (blood) to a garden (heart muscle). Over time, some debris (atherosclerotic plaque) builds up inside the pipe, partially blocking the flow. Suddenly, part of the debris breaks off (ruptures), and more debris (thrombus) accumulates rapidly at this spot, almost blocking the entire pipe. The water flow to the garden is significantly reduced, and the plants (heart muscle) start to suffer from lack of water (oxygen).

Atherosclerosis is a condition where fatty deposits, cholesterol, and other substances build up in the walls of arteries, forming plaques. These plaques can become unstable and rupture, leading to the formation of a thrombus. In the coronary arteries, this process can significantly reduce or block the flow of oxygen-rich blood to the heart muscle, causing chest pain or other symptoms associated with unstable angina or myocardial infarction (heart attack).

 

✘Incorrect answer options:

Atherosclerosis leading to reduced oxygen supply to tissues. While atherosclerosis is involved in unstable angina, this option does not fully capture the acute nature of the condition, specifically the role of plaque rupture and thrombus formation in causing symptoms.

A ruptured atherosclerotic plaque, thrombus formation, and subsequent embolus formation leading to complete occlusion and infarction. This option describes a scenario more typical of a heart attack (myocardial infarction) rather than unstable angina. While unstable angina can progress to a heart attack, it does not necessarily involve embolus formation or complete occlusion.

Spontaneous resolution of atherosclerosis, improving blood flow and symptoms. This option is incorrect as atherosclerosis does not spontaneously resolve. Instead, it typically progresses and can lead to complications such as unstable angina or myocardial infarction if not properly managed.

 

References

• Libby, P., Bonow, R. O., Mann, D. L., & Zipes, D. P. (2008). Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Saunders Elsevier.
• Thygesen, K., Alpert, J. S., & White, H. D. (2007). Universal definition of myocardial infarction. Journal of the American College of Cardiology, 50(22), 2173–2195.

EXPLANATION

 

✔Correct answer:

Each of the listed scenarios. Angina is caused by reduced blood flow to the heart muscle, resulting in insufficient oxygen supply to meet the heart's demands. In the context of stable angina, symptoms are typically predictable and occur during activities or situations that increase the demand for oxygen in the heart muscle. The scenarios listed in the options all have the potential to increase the heart's demand for oxygen or decrease oxygen supply, thus can trigger angina symptoms.

• Consuming and digesting a sizable meal. After a large meal, the body directs more blood to the digestive system to aid in digestion. This diversion can potentially reduce the blood flow available to the heart muscle, especially if there are blockages in the coronary arteries, and increase the heart's workload, requiring it to pump harder to distribute nutrients.
• Engaging in vigorous physical activities like sprinting up stairs. Physical exertion increases the heart rate and blood pressure, thereby increasing the heart's demand for oxygen. If the coronary arteries are narrowed, they may not be able to supply enough oxygen-rich blood to meet the heart's increased demands during vigorous activities.
• Smoking a cigarette. Smoking a cigarette can cause the coronary arteries to constrict, reducing blood flow to the heart muscle. Additionally, the chemicals in cigarette smoke can reduce the oxygen-carrying capacity of the blood. Both effects increase the heart's demand for oxygen and make it harder for the heart to get the oxygen it needs.

Imagine the heart as a car engine and oxygen as the fuel. Just like a car engine needs more fuel when it's running fast or under heavy load, the heart needs more oxygen when it's working hard, like during physical activity or after a large meal. Smoking a cigarette is like putting a kink in the fuel line; even if the engine is idling, it might not get enough fuel because the supply is restricted.

The heart muscle requires a constant supply of oxygen-rich blood to function. This is usually provided by the coronary arteries. During situations that increase the heart's workload (like physical exertion or stress), the heart muscle requires more oxygen. In the case of angina, the coronary arteries are narrowed due to atherosclerosis or other conditions, limiting the increase in blood flow needed during these high-demand situations, leading to the symptoms of angina.

 

✘Incorrect answer options:

The incorrect assumption would be to select any one of the scenarios individually, as all of them can potentially increase the heart's demand for oxygen or decrease oxygen supply, thereby possibly triggering angina symptoms.

 

References

• Kasper, D. L., Fauci, A. S., Hauser, S. L., Longo, D. L., Jameson, J. L., & Loscalzo, J. (2020). Harrison's Principles of Internal Medicine. McGraw-Hill Education.
• Lilly, L. S. (2016). Pathophysiology of Heart Disease: A Collaborative Project of Medical Students and Faculty. Wolters Kluwer.

EXPLANATION

 

✔Correct answer:

A ruptured atherosclerotic plaque with a subsequent thrombus, often resulting in complete vessel occlusion. Unstable angina is primarily caused by the rupture of an atherosclerotic plaque in a coronary artery. The rupture leads to the exposure of blood to the inner materials of the plaque, triggering the clotting cascade and the formation of a thrombus (blood clot). This thrombus can partially or intermittently completely occlude the coronary artery, leading to reduced blood flow and oxygen supply to the myocardium (heart muscle). This reduction in blood flow and oxygen supply can cause chest pain and other symptoms associated with unstable angina. Unlike a myocardial infarction (heart attack), in unstable angina, the blood flow reduction is typically not complete or sustained enough to cause full-thickness heart muscle death.

Think of a coronary artery as a busy highway supplying essential goods (oxygenated blood) to a city (heart muscle). An atherosclerotic plaque is like a fragile cargo on a truck. If the cargo (plaque) suddenly breaks (ruptures), it spills contents onto the highway, causing an emergency response (clotting cascade) and a traffic jam (thrombus), which intermittently blocks the flow of traffic (blood). The city (heart muscle) experiences shortages (oxygen deficiency), leading to problems (angina symptoms). Unlike a complete roadblock (heart attack), the blockage here might clear up intermittently, but the risk of a severe blockage is always present.

The coronary arteries supply oxygen-rich blood to the heart muscle. Atherosclerosis involves the buildup of plaques composed of fats, cholesterol, and other substances in these arteries. When a plaque ruptures, it exposes its contents, leading to the activation of platelets and the clotting cascade, resulting in thrombus formation. This thrombus can fluctuate in size, intermittently blocking the artery. This intermittent blockage leads to episodes of reduced blood flow to the heart muscle, causing the symptoms of unstable angina.

 

✘Incorrect answer options:

Atherosclerotic plaques reducing oxygen supply to cardiac tissue. While atherosclerotic plaques do reduce blood flow, this option does not specifically address the acute and unstable nature of the condition, which is due to plaque rupture and thrombus formation.

A ruptured atherosclerotic plaque with a subsequent thrombus that inevitably breaks up, leading to complete occlusion and myocardial infarction. This option inaccurately suggests that unstable angina always leads to myocardial infarction, which is not necessarily the case. While unstable angina increases the risk of a heart attack, not all episodes result in myocardial infarction.

Atherosclerotic plaques that spontaneously resolve, improving blood flow and alleviating symptoms. This option is incorrect as atherosclerotic plaques do not spontaneously resolve. In fact, they are the primary cause of the reduced blood flow seen in coronary artery disease.

 

References

• Libby, P., Bonow, R. O., Mann, D. L., & Zipes, D. P. (2008). Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Saunders Elsevier.
• Thygesen, K., Alpert, J. S., & White, H. D. (2007). Universal definition of myocardial infarction. Journal of the American College of Cardiology, 50(22), 2173–2195.

EXPLANATION

 

✔Correct answer:

Angina pectoris. Angina pectoris is the medical term used to describe chest pain or discomfort that occurs when an area of the heart muscle doesn't receive enough oxygen-rich blood. It is often a symptom of underlying coronary artery disease and is typically triggered by physical exertion or emotional stress. The pain usually resolves with rest or medication, such as nitroglycerin, which improves blood flow to the heart muscle and thus oxygen supply. Tina's symptoms, as described, match the classic presentation of angina pectoris.

Think of the heart muscle as a runner who needs a steady supply of oxygen (delivered by blood) to keep running. If the path narrows (narrowed coronary arteries), less oxygen gets through, and the runner (heart muscle) starts to struggle and signals distress (chest pain). Resting or opening the path (with medication) helps the runner recover by improving oxygen supply.

During physical exertion or emotional stress, the heart muscle requires more oxygen as the heart rate and blood pressure increase. In conditions like coronary artery disease, where the arteries supplying the heart muscle are narrowed, this increased demand for oxygen can't be met adequately. The mismatch between oxygen supply and demand leads to ischemia (reduced blood flow) in the heart muscle and the sensation of chest pain, known as angina pectoris.

 

✘Incorrect answer options:

Atheroma. An atheroma is a deposit of plaque within the wall of an artery. While atheromas can lead to coronary artery disease and contribute to the development of angina pectoris, the term itself does not describe chest pain or symptoms experienced by the patient.

Atherosclerosis. Atherosclerosis is the process of plaque buildup in the arteries, leading to narrowing and hardening of the arteries. It's a condition that can lead to angina pectoris but is not synonymous with the symptom of chest pain itself.

Ischemia. Ischemia refers to a reduced blood supply to an organ or tissue, causing a shortage of oxygen and nutrients needed for cellular metabolism. While ischemia in the heart muscle due to reduced coronary blood flow can cause angina pectoris, the term "ischemia" is more general and can apply to any organ or tissue, not just the heart.

 

References

• Mann, D. L., Zipes, D. P., Libby, P., & Bonow, R. O. (2015). Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Elsevier Health Sciences.
• American Heart Association. (2021). Angina (Chest Pain). [online] Available at: https://www.heart.org/en/health-topics/heart-attack/angina-chest-pain

EXPLANATION

 

✔Correct answer:

True. The statement is correct. Angina pectoris is indeed a term that describes a temporary form of chest pain, pressure, or discomfort. It is caused by reduced blood flow (ischemia) to the heart muscle, typically resulting from narrowing or blockage of one or more of the coronary arteries. Angina is considered a symptom of coronary artery disease, not a disease in itself. The pain or discomfort usually occurs when the heart muscle requires more oxygen than it receives, such as during physical exertion or stress, and it typically subsides with rest or medication that improves blood flow or reduces the heart's oxygen demand.

Think of angina like a warning light on a car's dashboard indicating that the engine (heart) isn't getting enough fuel (oxygen-rich blood). Just like the warning light turns off when the problem is addressed (e.g., adding fuel or stopping the car to let the engine rest), angina symptoms typically subside when the heart's demand for oxygen is met or when the blood flow is improved.

During episodes of angina, the heart muscle (myocardium) is temporarily deprived of adequate oxygen, usually due to a partial blockage or narrowing of the coronary arteries (atherosclerosis). This lack of oxygen can cause the sensation of chest pain or discomfort (angina pectoris). Angina is typically relieved by rest or medication, such as nitroglycerin, which helps to dilate the blood vessels and improve blood flow to the heart muscle or reduce the heart's oxygen demand.

 

References

• Mann, D. L., Zipes, D. P., Libby, P., & Bonow, R. O. (2015). Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Elsevier Health Sciences.
• American Heart Association. (2021). Angina (Chest Pain). [online] Available at: https://www.heart.org/en/health-topics/heart-attack/angina-chest-pain.

EXPLANATION

 

✔Correct answer:

"Put a nitroglycerine tablet under your tongue every five minutes, up to three doses. Head to the hospital if the pain doesn't subside." Nurse Olivia should instruct Michael to use the nitroglycerine tablets as a rapid response to anginal pain. The sublingual (under the tongue) route is preferred for its rapid absorption. The standard advice is to take one dose when experiencing chest pain, and if the pain is not relieved, to take another dose after five minutes, for a maximum of three doses. If the pain persists after three doses (totaling 15 minutes), it could indicate a more serious condition, such as a myocardial infarction (heart attack), and immediate medical attention is necessary.

Think of the nitroglycerine tablet as a fire extinguisher for chest pain. If there's a small fire (angina), you use the extinguisher (nitroglycerine tablet). If the fire doesn't go out after the first attempt, you try again, up to three times. If the fire still isn't out, it's time to call the professionals (go to the hospital).

Nitroglycerine acts as a vasodilator, relaxing and widening blood vessels. This reduces the workload on the heart by decreasing the resistance it must overcome to pump blood (afterload) and the volume of blood returning to it (preload). The decrease in workload reduces the heart's demand for oxygen, which is beneficial during an episode of angina where the heart's oxygen supply is compromised.

 

✘Incorrect answer options:

"If you start to have chest pain, lie down and place a tablet under your tongue. If the pain persists, take another tablet after 5 minutes." This option doesn't provide a clear protocol for seeking medical attention after the maximum number of doses, which is crucial in case of severe or ongoing cardiac events.

"Place a tablet under your tongue and if the pain doesn't improve within 15 minutes, go to the hospital." This option suggests waiting 15 minutes after a single dose before seeking medical help, which delays the potential for necessary immediate intervention after the standard three doses.

"Keep doing what you're doing and if the pain doesn't go away in 10 minutes, start taking the nitroglycerine tablets once every 5 minutes for 15 minutes, and then lie down." This advice is confusing and delays the administration of nitroglycerine. Immediate action is crucial when dealing with anginal pain, and this option does not provide clear, immediate steps for taking the medication or for seeking medical help if the pain persists.

 

References

• American Heart Association. (2021). Angina (Chest Pain). [online] Available at: https://www.heart.org/en/health-topics/heart-attack/angina-chest-pain
• Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12th Edition. Brunton, L., Chabner, B., & Knollmann, B. (2011).