Acute Decompensated Heart Failure After Anterior Myocardial Infarction: A Case-Based Analysis of Mechanism and Presentation in a 68-Year-Old Adult
[Author Name]
College of Nursing and Health Care Professions, Grand Canyon University
NRS-455 Pathophysiology
Topic 4 Assignment
[Instructor Name]
August 11, 2026
Composite case written as a model document. No real patient, employer or clinician is described.
Case Presentation
The patient is a composite 68-year-old man built for this paper, admitted from the emergency department with 6 days of worsening breathlessness. His history includes an anterior wall myocardial infarction 14 months ago treated with a stent to the left anterior descending artery, hypertension for 12 years, type 2 diabetes, and a 30 pack-year smoking history that ended after the infarction. An echocardiogram 3 months ago recorded an ejection fraction of 32 percent against a normal range of 55 to 70 percent. Two details explain the timing of this admission: he finished his last diuretic tablet 8 days ago and did not refill it, and he ate restaurant food for 4 days while family visited.
He now sleeps propped on three pillows and wakes twice a night short of breath, sitting on the edge of the bed for 10 to 15 minutes before he can lie down again. Both ankles are swollen to mid-shin with 2+ pitting edema. In the 6 days before admission the patient gained 4.5 kg, a change that represents roughly 4.5 L of retained fluid rather than any gain in body mass. Walking the 40 m from the car to the emergency department entrance left him unable to finish a sentence. He reports no chest pain, no fever and no cough productive of purulent sputum.
On examination his blood pressure is 148/92 mmHg, heart rate 104 and regular, respiratory rate 26 and temperature 36.8 C, with oxygen saturation of 88 percent on room air rising to 94 percent on 2 L by nasal cannula. Jugular venous distension is visible to 10 cm with the head of the bed at 45 degrees. Crackles are audible to the mid-lung fields bilaterally and an S3 gallop is present. Hands and feet are cool with capillary refill of 3 seconds. B-type natriuretic peptide is 1,840 pg/mL, sodium 133 mmol/L, potassium 4.1 mmol/L, and creatinine 1.6 mg/dL against a baseline of 1.1. Troponin is 0.06 ng/mL on two draws 4 hours apart and flat. The chest radiograph shows cardiomegaly, upper lobe vascular redistribution, interstitial edema and small bilateral pleural effusions.
Pathophysiology: From Lost Muscle to Rising Pressures
Heart failure with reduced ejection fraction begins here with muscle that no longer contracts. The anterior infarction replaced a segment of left ventricular myocardium with non-contractile scar, so the ventricle now ejects a smaller fraction of the volume it holds at the end of diastole, in this case 32 percent. The chamber responds by dilating and remodeling, which briefly recruits the Frank-Starling relationship because stretched fibers contract more forcefully. The benefit is temporary. As the chamber enlarges, wall tension rises with its radius, so the surviving myocytes work harder and consume more oxygen while moving less blood, and the remodeled ventricle becomes both weaker and more oxygen hungry (McCance & Huether, 2019).
Falling stroke volume is read by baroreceptors as falling perfusion, and the body answers with the response it keeps for blood loss. Sympathetic outflow raises heart rate and constricts arterioles. Reduced renal perfusion triggers renin release, and the renin-angiotensin-aldosterone cascade produces angiotensin II, a potent vasoconstrictor, and aldosterone, which holds sodium and water. Antidiuretic hormone adds free water. Compensation is the problem: the same sympathetic and renin-angiotensin-aldosterone activation that protects perfusion in a hemorrhage raises preload and afterload against a ventricle that can tolerate neither. Sustained over months, that circuit also drives fibrosis and further remodeling, which is why the classes that interrupt it alter survival rather than only comfort (Heidenreich et al., 2022).
The retained volume has to sit somewhere. Left ventricular end-diastolic pressure rises, and because no valve separates the left atrium from the pulmonary veins, that pressure is transmitted backward into the pulmonary capillary bed. When capillary hydrostatic pressure exceeds plasma oncotic pressure, fluid crosses into the interstitium faster than the lymphatics can clear it, and once the interstitial space is full, into the alveoli themselves (Norris, 2019). Oxygen has further to diffuse and ventilated alveoli are no longer matched to perfused ones, which is what a saturation of 88 percent measures. The same congestion travels backward on the right side into the systemic veins and, through renal venous congestion and reduced forward flow, into the kidney.
From Mechanism to Presentation
Each finding in the case belongs to a step above. Orthopnea is not a symptom in search of a mechanism: lying flat returns fluid from the legs and abdomen to the central circulation, and a ventricle already at the top of its pressure-volume curve passes that volume straight back into the pulmonary capillaries. The three pillows are the patient's own correction. The nocturnal waking follows the same physics with a delay, as interstitial fluid reabsorbed from the legs accumulates centrally during sleep. Crackles are the sound of fluid-filled alveoli reopening on inspiration, and the level they reach in the chest tracks how far the flooding has climbed.
The circulatory findings map just as directly. Cardiac output is heart rate multiplied by stroke volume, so when stroke volume falls the only variable left to raise is rate, and a resting heart rate of 104 is compensation rather than anxiety. Cool hands and a capillary refill of 3 seconds are the arteriolar constriction that defends central pressure by sacrificing skin and muscle flow. Jugular venous distension at 10 cm and 2+ pitting edema measure the same systemic venous congestion at opposite ends of the body. The S3 gallop is the sound of a large volume striking a stiff and already loaded ventricle in early diastole.
The laboratory values complete the chain rather than opening a new one. B-type natriuretic peptide of 1,840 pg/mL is released by stretched ventricular myocardium, so it is not only a marker but the body's own counter-regulatory attempt to shed sodium, overwhelmed by the pressure it is trying to correct. Sodium of 133 mmol/L is dilutional, produced by antidiuretic hormone holding water rather than by any loss of sodium. Creatinine of 1.6 against a baseline of 1.1 reflects a kidney caught between reduced forward flow and raised venous pressure. Flat troponin across two draws matters for what it excludes: this is decompensation of an old injury, not a new one.
What the Nurse Monitors and Teaches
Monitoring follows the mechanism. The daily weight is the most sensitive congestion measure the nurse controls, because 2 to 3 L can accumulate before pitting edema is visible, and it is trustworthy only when it is taken on the same scale, at the same hour, before breakfast and after voiding. Intake and output are recorded against that weight rather than beside it. Oxygen is titrated to hold saturation above 92 percent, and the head of the bed stays elevated because upright positioning lowers venous return to a ventricle that cannot manage the volume. Potassium and creatinine are followed during diuresis, since the kidney is already strained and scarred myocardium is an arrhythmia substrate.
Drug classes are worth understanding at this level even though selection and dosing belong to the prescriber. A loop diuretic addresses congestion, which is the symptom that brought this patient in. The classes that change the course act on the cascade described above: agents that block the renin-angiotensin system, mineralocorticoid receptor antagonists, beta blockers and sodium-glucose cotransporter 2 inhibitors interrupt neurohormonal activation and remodeling rather than volume alone (Heidenreich et al., 2022). Teaching rests on the same chain. The patient leaves knowing to weigh himself daily, to call for a gain of 2 kg over 48 hours, to hold sodium to the target set with the dietitian, and never to run out of a refill again.
References
American Heart Association. (2024). What is heart failure? https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure
Centers for Disease Control and Prevention. (2024). About heart failure. U.S. Department of Health and Human Services. https://www.cdc.gov/heart-disease/about/heart-failure.html
Heidenreich, P. A., Bozkurt, B., Aguilar, D., Allen, L. A., Byun, J. J., Colvin, M. M., Deswal, A., Drazner, M. H., Dunlay, S. L., Evers, L. R., Fang, J. C., Fedson, S. E., Fonarow, G. C., Hayek, S. S., Hernandez, A. F., Khazanie, P., Kittleson, M. M., Lee, C. S., Link, M. S., ... Yancy, C. W. (2022). 2022 AHA/ACC/HFSA guideline for the management of heart failure: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation, 145(18), e895-e1032.
McCance, K. L., & Huether, S. E. (2019). Pathophysiology: The biologic basis for disease in adults and children (8th ed.). Elsevier.
National Heart, Lung, and Blood Institute. (2022). Heart failure. U.S. Department of Health and Human Services, National Institutes of Health. https://www.nhlbi.nih.gov/health/heart-failure
Norris, T. L. (2019). Porth's pathophysiology: Concepts of altered health states (10th ed.). Wolters Kluwer.
How this NRS 455 Topic 4 example is structured
In many sections this topic asks for a case-based analysis that explains a disease process and the presentation it produces, rather than an essay about the disease; your classroom's instructions and rubric decide the exact form, so read the assignment page before you use this NRS 455 Topic 4 example as a shape. The paper is ordered as a chain. The case comes first, with the history, the findings and the laboratory values a nurse would actually hold. The mechanism follows, moving from lost contractile muscle to neurohormonal compensation to the pressures that push fluid out of the pulmonary capillaries. The third sheet does what rubrics reward most: it takes each finding from the case and names the step that produced it. Monitoring and teaching close the paper. The patient is a composite.
NRS-455 Topic 4 questions, answered
What does NRS 455 Topic 4 usually ask for?
In many sections this topic asks for a case-based paper that explains a disease process and connects it to the patient's presentation, often with nursing implications attached. Your classroom's instructions and rubric decide the exact form, including headings, length and whether a case is supplied for you, so read the assignment page before treating any example as the required shape.
How much pharmacology belongs in a BSN pathophysiology case study?
Enough to show which step of the mechanism a drug class interrupts, and no more. Naming a loop diuretic as relief of congestion and renin-angiotensin blockade as interruption of remodeling is BSN-level reasoning. Dosing, titration and agent selection belong to the prescriber, and saying so plainly reads as awareness of scope rather than as a gap in the paper.
Do I need a real patient for a pathophysiology case study?
No, and using one creates a privacy problem you do not need. A composite built from a common presentation gives you every number the paper requires and lets you state clearly that no real patient is described. Say the case is a composite, then keep the physiology exact, because the physiology is what the rubric is actually measuring.
Write yours, or have the desk draft it
This paper is an original model document written by our desk, not a submitted student paper and not an official Grand Canyon University document. Read it for the moves, then write your own to the instructions in your classroom. If you want one built to your exact prompt and rubric, the first custom sample is free and arrives in 24 to 48 hours.