Valvular Disorder: Mitral Stenosis Nursing Management

EXPLANATION

 

✔Correct answer:

Cholesterol is a blood component whose levels typically decrease when unsaturated fats replace saturated fats in the diet. Cholesterol is a waxy, fat-like substance that's found in all cells of the body. The body needs cholesterol to make hormones, vitamin D, and substances that help digest foods. The body makes all the cholesterol it needs, but cholesterol also comes from the food we eat. Dietary cholesterol comes from animal sources, such as egg yolks, meat, and cheese. If too much LDL (low-density lipoprotein, or "bad" cholesterol) cholesterol circulates in the blood, it can build up in the walls of the arteries, including those of the heart, which can lead to atherosclerosis, a type of heart disease.

Replacing saturated fats (found in meats, dairy products, and many processed foods) with unsaturated fats (found in foods like nuts, seeds, fish, and vegetable oils) can help reduce cholesterol levels. This is because unsaturated fats can help reduce the levels of LDL cholesterol in the blood, which, when elevated, is a risk factor for atherosclerosis and heart disease.

Imagine your bloodstream as a highway and cholesterol as vehicles on this highway. LDL cholesterol is like a bunch of heavy trucks that can drop cargo (plaque) on the road, potentially blocking traffic and causing accidents (heart attacks or strokes). Replacing saturated fats with unsaturated fats in your diet is like replacing some of those heavy trucks with more efficient vehicles that are less likely to drop cargo on the road, thus keeping traffic (blood flow) moving smoothly.

Dietary changes can alter the lipid profile in the blood. Saturated fats tend to raise the level of LDL cholesterol in the blood. High levels of LDL cholesterol increase the risk of heart disease and stroke. Unsaturated fats, particularly polyunsaturated fats, can help reduce the levels of LDL cholesterol. Monounsaturated fats also have a beneficial effect on health by maintaining or increasing the level of HDL (high-density lipoprotein, or "good" cholesterol), which helps remove LDL cholesterol from the arteries.

 

✘Incorrect answer options:

Cholesterol can be completely controlled by avoiding certain foods. While diet plays a significant role in managing cholesterol levels, other factors like genetics, age, and underlying medical conditions also influence cholesterol levels. Hence, cholesterol levels cannot be "completely controlled" by diet alone.

Cholesterol is found in a wide variety of foods, including both plant and animal sources. Cholesterol is only found in animal products. Plants do not contain cholesterol, although some plant-based foods are rich in phytosterols, which can help lower cholesterol levels.

Everyone would be healthier without cholesterol since it is the root cause of many diseases. Cholesterol itself is essential for the body. It is needed to build cells and produce certain hormones. The problem arises when the levels, especially of LDL cholesterol, are too high, contributing to the development of diseases like atherosclerosis. However, not all cholesterol is harmful; for instance, high levels of HDL cholesterol are actually protective.

 

References

• Kumar, V., Abbas, A. K., & Aster, J. C. (2020). Robbins and Cotran Pathologic Basis of Disease (10th ed.). Elsevier.
• Grundy, S. M., Cleeman, J. I., Daniels, S. R., Donato, K. A., Eckel, R. H., Franklin, B. A., ... & Costa, F. (2005). Diagnosis and management of the metabolic syndrome: an American Heart Association/National Heart, Lung, and Blood Institute scientific statement. Circulation, 112(17), 2735-2752.

EXPLANATION

 

✔Correct answer:

Wait for the arrival of Karen's family and discuss the dietary restrictions with both the patient and her family. Discussing the dietary restrictions with both Karen and her family upon their arrival is an effective approach for a few reasons. It involves direct communication and ensures that everyone understands the importance of the dietary restrictions in managing Karen's severe hypertension. By engaging in a conversation with both Karen and her family, Nurse Olivia can address any concerns or misconceptions they might have, provide education on the reasons behind the dietary restrictions, and even suggest alternatives to "good home-cooked food" that align with the prescribed 2-gram sodium diet. This inclusive approach fosters a supportive environment, encourages adherence to the dietary regimen, and emphasizes the role of the family in supporting Karen's health management.

Imagine Karen's treatment as a team sport, where Karen is the player, her family are the supporters, and Nurse Olivia is the coach. Just as a coach discusses strategies with the entire team to ensure everyone is on the same page and working towards the same goal, Nurse Olivia discusses the dietary plan with Karen and her family to ensure everyone understands and supports the diet plan, contributing to Karen's success in managing her hypertension.

Sodium plays a critical role in regulating blood volume and pressure. In the case of hypertension, excess sodium can cause the body to retain water, leading to an increase in blood volume and, consequently, increased blood pressure. A 2-gram sodium diet aims to limit this effect by controlling sodium intake, thereby helping to manage blood pressure levels. Educating the patient and the family about the importance of adhering to this dietary restriction is crucial for effective hypertension management.

 

✘Incorrect answer options:

Intercept the family members before they enter Karen's room to inform them about the prescribed diet. This approach might come across as confrontational or secretive, potentially creating tension or resistance from the family. It's generally better to have open communication with the patient present.

Inform Karen that salt is completely off-limits because it will elevate her blood pressure further. While it's crucial to control salt intake in a patient with hypertension, this approach is overly simplistic and might not be practical or sustainable. Education should focus on how to manage and reduce sodium intake rather than imposing a complete ban.

Request a dietician to come in for specialized dietary education for the client. While involving a dietitian is a good idea for detailed dietary education, it doesn't address the immediate situation of the family bringing in food. Direct communication with the patient and family is essential to manage the current situation effectively and to set the stage for any future educational sessions.

 

References

• Appel, L. J., Brands, M. W., Daniels, S. R., Karanja, N., Elmer, P. J., & Sacks, F. M. (2006). Dietary approaches to prevent and treat hypertension: a scientific statement from the American Heart Association. Hypertension, 47(2), 296-308.
• Sacks, F. M., Svetkey, L. P., Vollmer, W. M., Appel, L. J., Bray, G. A., Harsha, D., ... & Karanja, N. (2001). Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. New England Journal of Medicine, 344(1), 3-10.

EXPLANATION

 

✔Correct answer:

A bout of rheumatic fever. Rheumatic fever, an inflammatory disease that can develop as a complication of inadequately treated strep throat or scarlet fever, is the most likely childhood health history Nurse Olivia will uncover. Rheumatic fever can cause permanent damage to the heart, including the heart valves, a condition known as rheumatic heart disease. In this case, Mrs. Williams' severe mitral stenosis and mitral regurgitation can be complications of rheumatic heart disease, a common long-term consequence of rheumatic fever. The fact that Mrs. Williams was diagnosed during childhood and the nature of her cardiac condition (mitral valve issues) strongly point towards a history of rheumatic fever, given its known association with causing chronic valvular disorders, particularly affecting the mitral valve.

Think of the heart as a house with doors (valves) that regulate the flow of traffic (blood) in and out of the rooms (chambers). Rheumatic fever is like a storm that damages the doors, making them unable to open or close properly. Over time, just like doors that don't work well can lead to problems in a house, such as security issues or energy inefficiency, damaged heart valves can lead to serious health problems, as they disrupt the normal flow of blood through the heart.

In rheumatic fever, the body's immune response to a streptococcal infection mistakenly attacks its own tissues, particularly targeting the heart, joints, skin, and brain. When the heart is involved, the condition is termed rheumatic heart disease. The heart valves, especially the mitral valve, can become inflamed in a process called valvulitis. This inflammation can lead to scarring and deformity of the valve leaflets, resulting in stenosis (narrowing of the valve opening, impeding forward flow of blood) or regurgitation (inability of the valve to close properly, allowing backward flow of blood). These changes disrupt normal hemodynamics and can lead to heart failure, which is likely why Mrs. Williams was on medications like digoxin (to strengthen heart muscle contractions) and furosemide (a diuretic to reduce fluid overload).

 

✘Incorrect answer options:

A history of poliomyelitis. Polio is a viral disease that can lead to paralysis and muscle weakness, not directly related to valvular heart disease. It affects the nervous system rather than the cardiovascular system.

An episode of chicken pox. Chickenpox, caused by the varicella-zoster virus, primarily affects the skin and sometimes the nervous system but is not typically associated with heart valve disease.

An incidence of meningitis. Meningitis, an inflammation of the membranes surrounding the brain and spinal cord, can be a severe illness but is not directly linked to the development of chronic valvular heart disease like mitral stenosis or regurgitation.

 

References

• Lewis, S. M., Heitkemper, M. M., Bucher, L., Harding, M., Kwong, J., & Roberts, D. (2020). Medical-Surgical Nursing: Assessment and Management of Clinical Problems (11th ed.). Elsevier.
• Jarvis, C. (2019). Physical Examination and Health Assessment (8th ed.). Elsevier.

EXPLANATION

 

✔Correct answer:

Development of systemic emboli. Bacterial endocarditis involves the formation of vegetations (clumps of bacteria and cell debris) on the heart valves or endocardium. These vegetations can break off and form emboli, which can then travel through the bloodstream to other parts of the body. This can lead to a range of serious complications, depending on where the emboli lodge. For example, if an embolus travels to the brain, it can cause a stroke. If it travels to the kidneys, it can cause renal failure, and so on. Therefore, monitoring for the development of systemic emboli is crucial in the management of a patient with bacterial endocarditis because of the potential for these emboli to cause severe and life-threatening complications in various organs.

Think of the bloodstream like a busy highway and the vegetations in endocarditis like debris on the road. Just like debris can get picked up and carried to different parts of the highway, causing accidents or blockages wherever they land, in endocarditis, pieces of the vegetations can break off and travel to different parts of the body, causing blockages (emboli) and potentially serious damage wherever they lodge.

In bacterial endocarditis, the heart valves or the inner lining of the heart chambers become infected, leading to the formation of vegetations. These vegetations are masses of platelets, fibrin, microcolonies of microorganisms, and scant inflammatory cells. They are friable and can easily fragment and dislodge into the bloodstream, becoming emboli. These emboli can travel through the bloodstream and obstruct blood vessels in various organs (brain, kidneys, spleen, etc.), leading to ischemia (inadequate blood supply) and infarction (tissue death due to lack of oxygen) in these organs.

 

✘Incorrect answer options:

Sporadic or sustained fever. While fever is a common symptom of bacterial endocarditis and should be monitored, it is not as immediately threatening as the development of systemic emboli.

Signs of congestive heart failure. Congestive heart failure can be a complication of bacterial endocarditis due to valve dysfunction. It's important to monitor for, but the formation of systemic emboli represents a more direct and acute complication of endocarditis itself.

The onset or change of a heart murmur. While new or changing murmurs are significant findings in bacterial endocarditis and can indicate worsening valve function, the development of systemic emboli is a more critical and potentially life-threatening complication that requires immediate attention.

 

References

• Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Elsevier.
• Harrison's Principles of Internal Medicine. McGraw-Hill Education.

EXPLANATION

 

✔Correct answer:

Difficulty breathing upon exertion. Mitral regurgitation is a condition in which the heart's mitral valve does not close tightly, allowing blood to flow backward in the heart. When the valve does not function properly, blood cannot move through the heart or to the rest of the body efficiently, causing fatigue and shortness of breath, especially during exertion or when lying down. Difficulty breathing upon exertion (dyspnea) is a hallmark symptom of mitral regurgitation and other forms of heart failure. This occurs because the regurgitation increases the volume and pressure in the left atrium, which can subsequently lead to pulmonary congestion and reduced lung compliance, making it harder to breathe, especially when active.

Imagine a water pump (the heart) connected to a series of hoses (blood vessels). If one of the valves in the pump doesn't seal properly, water (blood) leaks back into the pump chamber instead of flowing out efficiently. When the pump tries to push water through the system during demanding tasks (exertion), the leak makes it much harder for the water to reach its destination (the body's organs), causing the system (the person) to struggle, especially when trying to move a lot of water (during physical activity).

In mitral regurgitation, the incomplete closure of the mitral valve during systole (heart muscle contraction) leads to the backward flow of blood from the left ventricle to the left atrium. This backflow increases the pressure in the left atrium and subsequently in the pulmonary veins and capillaries. The increased pulmonary pressures can cause fluid to leak into the alveolar spaces, leading to pulmonary edema and resulting in difficulty breathing, particularly during exertion when the demand for oxygen increases. This physiological change explains why dyspnea on exertion is a common and significant symptom of mitral regurgitation.

 

✘Incorrect answer options:

High levels of creatine phosphokinase. Creatine phosphokinase (CPK) is an enzyme found in the heart, brain, and skeletal muscles. High levels of CPK are more commonly associated with muscle damage, including myocardial infarction (heart attack), not specifically with mitral regurgitation.

Episodes of confusion. While confusion can be a symptom of advanced heart failure due to decreased perfusion to the brain, it is not a direct or common symptom of mitral regurgitation, especially in the earlier stages or without the presence of advanced heart failure.

Chest discomfort or pain. Chest pain or discomfort can be associated with various heart conditions, primarily those involving coronary artery disease or myocardial infarction. It's not typically a direct symptom of mitral regurgitation unless the condition has led to heart failure or other cardiac complications.

 

References

• Hammer, G. D., & McPhee, S. J. (2019). Pathophysiology of Disease: An Introduction to Clinical Medicine (8th ed.). McGraw-Hill Education.
• Lilly, L. S. (2016). Pathophysiology of Heart Disease: A Collaborative Project of Medical Students and Faculty (6th ed.). Wolters Kluwer.

EXPLANATION

 

✔Correct answer:

Damage to one or more heart valves. Endocarditis is an infection of the inner lining of the heart chambers and heart valves (endocardium). It commonly occurs when bacteria or other germs from another part of the body, such as the mouth, spread through the bloodstream and attach to damaged areas in the heart. If endocarditis is not treated quickly, it can damage or destroy the heart valves. This damage can lead to a heart murmur, which is an abnormal sound heard during a heartbeat. The murmur results from turbulent blood flow through the damaged valve(s). Therefore, in the context of a patient with endocarditis, the development of a new heart murmur is most likely attributable to damage to one or more of the heart valves caused by the infection.

Imagine the heart as a house with doors (the valves) that open and close to let people (blood) in and out of the rooms (chambers of the heart). Endocarditis is like a termite infestation in the doors that damages their structure. When damaged, the doors don't open or close smoothly, and as people move through these faulty doors, the noise (murmur) from the creaky, damaged door is much louder and different from the normal sound of a well-maintained door.

A heart murmur is the sound of blood flowing that can be heard during a heartbeat. Murmurs can be innocent (not caused by heart problems) or abnormal. Abnormal murmurs are often a symptom of a problem with one or more of the heart valves. Each valve has a set of flaps (cusps or leaflets) that open and close once during each heartbeat. If a valve doesn't open or close properly, the blood flow through the heart to the body can be disrupted. Endocarditis can lead to such valve malfunctions by causing vegetations (growths) on the valves, scarring, or by causing the valve to perforate or leak, leading to turbulent blood flow and consequently a murmur.

 

✘Incorrect answer options:

Elevated blood pressure or hypertension. While hypertension can lead to certain types of heart murmurs over time due to the increased strain on the heart, it's not the most likely cause of a new murmur in the context of a patient with endocarditis.

The presence of a pulmonary embolism. A pulmonary embolism (a blood clot in the pulmonary artery) can lead to serious cardiovascular complications, but it does not directly cause heart murmurs. The symptoms of a pulmonary embolism are more likely to be related to respiratory function and not murmurs.

Elevated levels of potassium, or hyperkalemia. While severe hyperkalemia can affect the heart's rhythm and function, it does not cause heart murmurs. Symptoms and signs of hyperkalemia are usually related to muscular function and electrocardiogram (ECG) changes.

 

References

• Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. Elsevier.
• Harrison's Principles of Internal Medicine. McGraw-Hill Education.

EXPLANATION

 

✔Correct answer:

Pulmonary circulation. Mitral stenosis is a condition characterized by the narrowing of the mitral valve opening, leading to restricted blood flow from the left atrium to the left ventricle. This restriction leads to increased pressure in the left atrium, which subsequently causes increased pressure in the pulmonary veins and the pulmonary circulation. As a result, symptoms of congestion are most commonly noted in the pulmonary circulation. This can manifest as pulmonary edema, leading to symptoms such as shortness of breath, especially during exertion or when lying down, coughing, wheezing, and even hemoptysis in severe cases.

Think of the heart and lungs as a two-stage pump system, where the first stage pumps water (blood) from a reservoir (the body) into a holding tank (the left atrium). If the pipe leading out of the holding tank (the mitral valve) is narrowed, water backs up into the holding tank, causing it to overflow. If this holding tank is connected to a garden (the lungs), the overflow will lead to flooding in the garden (congestion in the pulmonary circulation).

In mitral stenosis, the narrowed mitral valve impedes blood flow from the left atrium to the left ventricle during diastole (heart relaxation). This obstruction leads to an accumulation of blood in the left atrium, causing increased pressure in this chamber. The increased pressure is transmitted backward into the pulmonary veins and subsequently the pulmonary capillaries, leading to increased pulmonary venous and capillary pressures (pulmonary hypertension). This pressure can push fluid into the alveoli, leading to pulmonary edema and symptoms related to pulmonary congestion.

 

✘Incorrect answer options:

Right atrial region. While the right atrium receives blood from the systemic circulation, it is not directly affected by mitral stenosis. Mitral stenosis primarily affects the left side of the heart and the pulmonary circulation.

Aortic region. The aortic region is involved in systemic circulation and is not the primary site of congestion in mitral stenosis. Mitral stenosis affects the flow between the left atrium and left ventricle, not the flow out of the left ventricle into the aorta.

Superior vena cava. The superior vena cava returns blood from the upper part of the body to the right atrium. It is not directly involved in the congestion caused by mitral stenosis, which primarily affects the left side of the heart and the pulmonary circulation.

 

References

• Hammer, G. D., & McPhee, S. J. (2019). Pathophysiology of Disease: An Introduction to Clinical Medicine (8th ed.). McGraw-Hill Education.
• Lilly, L. S. (2016). Pathophysiology of Heart Disease: A Collaborative Project of Medical Students and Faculty (6th ed.). Wolters Kluwer.

EXPLANATION

 

✔Correct answer:

Vegetables and whole grains. Unsaturated fatty acids are primarily found in plants and fish. Therefore, emphasizing a diet rich in vegetables and whole grains would help increase the intake of unsaturated fats, which are considered more heart-healthy compared to saturated fats. These fats can help improve blood cholesterol levels, thereby reducing the risk of heart disease. Vegetables and grains don't inherently contain large amounts of fats, but they are fundamental components of a heart-healthy diet that is rich in nutrients, fiber, and antioxidants. Additionally, they are typically part of dietary patterns that include other sources of unsaturated fats, such as nuts, seeds, fish, and vegetable oils.

Think of the heart like a car and unsaturated fats as high-quality fuel. Just as high-quality fuel helps the car run smoothly and efficiently, consuming unsaturated fats helps keep the heart running well by maintaining healthy blood vessels and reducing harmful cholesterol levels. Emphasizing vegetables and whole grains in the diet is like making sure the car not only gets the best fuel but also the necessary oil changes and maintenance (fiber, vitamins, minerals) to keep it in top condition.

Unsaturated fats, which include monounsaturated and polyunsaturated fats, are beneficial for heart health. They can help reduce the levels of low-density lipoprotein (LDL) cholesterol in the blood. High levels of LDL cholesterol are a risk factor for heart disease as they can lead to the buildup of plaques in the arteries, a condition known as atherosclerosis. Additionally, unsaturated fats can provide essential fatty acids that the body cannot produce, like omega-3 and omega-6 fatty acids, which are important for brain function and cell growth.

 

✘Incorrect answer options:

Organ meats like liver and other glandular organs. Organ meats are rich in nutrients but also high in cholesterol and saturated fats, which are not recommended in high quantities for a heart-healthy diet.

Red meats such as beef and pork. Red meats are typically high in saturated fats. While they can be a part of a balanced diet, they should be consumed in moderation, especially for individuals with cardiac issues.

Dairy products like enriched whole milk. Whole milk and other full-fat dairy products contain higher amounts of saturated fats. Low-fat or fat-free dairy options are generally recommended for heart health.

 

References

• Hu, F. B. (2002). Dietary pattern analysis: a new direction in nutritional epidemiology. Current Opinion in Lipidology, 13(1), 3-9.
• Estruch, R., Ros, E., Salas-Salvadó, J., Covas, M. I., Corella, D., Arós, F., ... & Martínez-González, M. A. (2018). Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. New England Journal of Medicine, 378(25), e34.

EXPLANATION

 

✔Correct answer:

Following prescribed medication therapy. In the case of a patient with mitral stenosis, adherence to prescribed medication therapy is crucial. Medications for conditions like mitral stenosis may include diuretics to manage fluid overload, anticoagulants to prevent thromboembolism (a significant risk due to blood stasis in the left atrium), and antiarrhythmics to manage atrial fibrillation (a common complication of mitral stenosis). Non-compliance with these medications can lead to exacerbation of symptoms, increase the risk of complications such as stroke (due to the formation of blood clots in the atrium), and potentially worsen the condition of the heart, making the surgical outcome less favorable and recovery more complicated.

Consider the heart as a garden water pump and the medications as the maintenance tools to keep it running smoothly. If you don't use the tools regularly (like oil for the parts, or clean water to prevent clogging), the pump's (heart's) efficiency drops, and the risk of a breakdown (complications like stroke or heart failure) increases significantly.

Mitral stenosis leads to increased pressure in the left atrium and the pulmonary circulation, causing symptoms such as shortness of breath, fatigue, and pulmonary edema. Medications play a critical role in managing these symptoms and preventing complications. For instance, diuretics help reduce fluid congestion, anticoagulants prevent the formation of clots in the atrium (which is especially prone to clots due to turbulent blood flow and potentially atrial fibrillation), and antiarrhythmics help to control heart rate and rhythm, reducing symptoms and the risk of stroke.

 

✘Incorrect answer options:

Adherence to dietary modifications. While important for overall health and managing risk factors for cardiovascular disease, non-compliance with dietary modifications does not pose as immediate or severe a risk as non-compliance with medication therapy in the context of mitral stenosis.

Regular dental care and hygiene. Poor dental hygiene can lead to infections that may affect the heart, particularly in patients with valve disease (a condition known as infective endocarditis). However, while still important, it is not as acutely risky as non-compliance with prescribed heart medications.

Abiding by activity restrictions. While it's important for patients with mitral stenosis to balance activity with rest and avoid excessive exertion that may exacerbate symptoms or lead to heart failure, non-compliance with activity restrictions is generally less immediately dangerous than non-compliance with medication therapy.

 

References

• Hammer, G. D., & McPhee, S. J. (2019). Pathophysiology of Disease: An Introduction to Clinical Medicine (8th ed.). McGraw-Hill Education.
• Lilly, L. S. (2016). Pathophysiology of Heart Disease: A Collaborative Project of Medical Students and Faculty (6th ed.). Wolters Kluwer.

EXPLANATION

 

✔Correct answer:

The presence of one P wave before each QRS complex. A normal sinus rhythm is characterized by a consistent rhythm where each heartbeat is initiated by the sinoatrial (SA) node, the natural pacemaker of the heart. This is reflected on an electrocardiogram (ECG) by specific patterns and intervals. The presence of one P wave before each QRS complex indicates that each heartbeat is being properly initiated by the SA node and that the electrical impulse is following the normal sequence through the heart. In a normal sinus rhythm, the P wave represents atrial depolarization, followed by the QRS complex representing ventricular depolarization. The consistent appearance of one P wave before each QRS complex suggests that the atria are contracting to fill the ventricles with blood before each ventricular contraction, which is a characteristic of normal sinus rhythm.

Think of the heart's rhythm as a dance routine. The P wave is like the lead dancer signaling the start of a new move (atrial contraction), and the QRS complex is the rest of the dance troupe following with their move (ventricular contraction). In a normal routine (sinus rhythm), each lead dancer's signal (P wave) is followed by the troupe's move (QRS complex) in a consistent and orderly fashion.

Normal sinus rhythm originates in the sinoatrial node, located in the right atrium. The electrical impulse from the SA node causes the atria to contract (atrial depolarization), represented by the P wave on the ECG. The impulse then travels to the atrioventricular (AV) node, through the bundle of His, and down the Purkinje fibers, causing the ventricles to contract (ventricular depolarization), represented by the QRS complex. The T wave represents ventricular repolarization or the recovery phase. The regular appearance of one P wave before each QRS complex, with a consistent P-R interval, and a normal rate (60-100 beats per minute) are key characteristics of a normal sinus rhythm.

 

✘Incorrect answer options:

The occurrence of 4 to 8 complexes in a 6-second rhythm strip. This statement relates to the heart rate calculation (number of complexes in a 6-second strip multiplied by 10 gives the rate per minute) but does not specifically describe normal sinus rhythm.

The ST segment elevation is higher than the PR interval. ST segment elevation can indicate myocardial infarction or pericarditis, not normal sinus rhythm. The PR interval is a separate measurement and its comparison with the ST segment elevation is not a criterion for normal sinus rhythm.

The duration of the QRS complex falls between 0.12 and 0.2 seconds. A QRS duration between 0.12 and 0.2 seconds is actually longer than normal and may indicate a bundle branch block or other conduction abnormality. A normal QRS complex duration is 0.06 to 0.10 seconds.

 

References

• Goldberger, A. L. (2006). Clinical Electrocardiography: A Simplified Approach (7th ed.). Elsevier Health Sciences.
• Wagner, G. S. (2012). Marriott's Practical Electrocardiography (12th ed.). Wolters Kluwer Health/Lippincott Williams & Wilkins.