NURS 215 Week 7 Research Paper Part 3: Final Paper Example

Heart Failure With Reduced Ejection Fraction: From Neurohormonal Compensation to Bedside Monitoring on a Telemetry Unit

Abstract

Heart failure with reduced ejection fraction (HFrEF), defined by an ejection fraction at or below 40%, is common among patients on telemetry units, and its routine care makes sense only in light of its mechanism. This final paper explains that mechanism and applies it to nursing. A myocardial injury or prolonged overload lowers stroke volume; sympathetic stimulation and renin-angiotensin-aldosterone signaling then restore pressure and perfusion, but their persistence produces fluid retention, raised afterload, loss of myocytes, fibrosis and chamber dilation. This remodeling feeds back on itself and accounts for the congestion and low-output findings nurses assess. Guideline-directed therapy works by blocking the same pathways, and a large trial of an SGLT2 inhibitor showed fewer heart failure events and deaths with the drug added. The paper concludes that daily weights, electrolyte and renal monitoring, vital sign checks before medications and mechanism-based teaching for self-care are direct applications of the pathophysiology.

Keywords: systolic heart failure, sympathetic activation, cardiac remodeling, guideline-directed therapy, telemetry nursing

Introduction

On the telemetry unit where I work, about a third of patients carry a diagnosis of heart failure, and most of them have a reduced ejection fraction. We weigh them every morning, record every cup of fluid, check potassium before giving their medications and hold some drugs when the heart rate or blood pressure is low. Patients often ask why, and new nurses sometimes treat these routines as rules rather than reasons. Worldwide, heart failure now affects an estimated 23 million people, and about half have the reduced ejection fraction form (Murphy et al., 2020). This paper explains the pathophysiology of that form, from the first injury to the heart through the compensatory responses that eventually drive the disease forward, and then shows how each routine assessment and medication follows from the mechanism. The aim is a paper a nurse could use to answer the patient's question: why does any of this matter?

Normal Cardiac Function

Cardiac output, the volume pumped each minute, equals the number of beats multiplied by the volume ejected per beat. Grossman and Porth (2014) describe stroke volume as depending on three factors. Preload is the stretch of the ventricular muscle at the end of filling, roughly the volume of blood returning to the heart. Afterload is the resistance the ventricle must overcome to eject blood, largely determined by arterial pressure and vascular resistance. Contractility is the inherent strength of the muscle's contraction independent of preload and afterload.

The Frank-Starling relationship links preload to output: within limits, the more the ventricle is stretched during filling, the more forcefully it contracts. A healthy heart uses this relationship moment to moment, pumping out whatever returns to it. The ejection fraction, the proportion of the end-diastolic volume ejected with each beat, is normally above about 50%. These ideas matter because heart failure is, at bottom, a failure of this system to match output to the body's needs, and because the body's attempts to restore output act on exactly these determinants.

Definition and Staging

The reduced-ejection-fraction form is diagnosed once ejection fraction falls to 40% or lower, together with progressive dilation of the ventricle and adverse remodeling (Murphy et al., 2020). Diagnosis rests on the history and physical examination, elevated natriuretic peptide levels and echocardiographic evidence of systolic dysfunction. The 2022 United States heart failure guideline, issued jointly by the three major cardiology and heart failure societies, describes heart failure in stages that emphasize progression: stage A for people at risk, such as those with hypertension or diabetes; stage B for people with structural heart disease but no symptoms, sometimes called pre-heart failure; stage C for people with current or past symptoms; and stage D for advanced heart failure (Heidenreich et al., 2022). The New York Heart Association functional classes, from no limitation in class I to symptoms at rest in class IV, describe how symptoms limit activity at a given time. Staging matters for nurses because it frames heart failure as a process that can often be slowed, not simply a label applied when symptoms appear.

The Initial Injury

Heart failure begins with an event or condition that damages the myocardium or increases its workload. The most common causes are coronary artery disease, especially myocardial infarction, long-standing hypertension and cardiomyopathies, including those caused by alcohol, chemotherapy, infections and genetic conditions (Grossman & Porth, 2014). A myocardial infarction removes a region of contracting muscle at once. Hypertension increases afterload for years, first producing hypertrophy and later, in some patients, dilation and systolic failure. Whatever the cause, the result is the same: stroke volume and cardiac output fall, and the body responds.

Neurohormonal Activation

Hartupee and Mann (2017) describe two compensatory systems as the best recognized responses to a fall in cardiac output: activation of the sympathetic nervous system and of the renin-angiotensin-aldosterone system. In the short term, both are protective.

The sympathetic response is fast. Baroreceptors sense the fall in pressure and output, and sympathetic outflow increases. Norepinephrine raises the heart rate and contractility, which increases output, and constricts arterioles and veins, which maintains blood pressure and shifts blood toward the heart, raising preload. For a heart that has just lost a region of muscle, these changes may keep the patient alive.

The renin-angiotensin-aldosterone system acts over hours to days. Reduced renal perfusion and sympathetic stimulation cause the kidneys to release renin, which leads to the formation of angiotensin II. Angiotensin II constricts arterioles, stimulates thirst and the release of antidiuretic hormone and triggers aldosterone secretion from the adrenal cortex. Aldosterone causes the kidneys to retain sodium and, with it, water. The resulting increase in blood volume raises preload, which, through the Frank-Starling relationship, helps the weakened ventricle pump more (Grossman & Porth, 2014).

The problem is that neither system switches off. Hartupee and Mann (2017) explain that with chronic activation, these responses impose hemodynamic stress and exert direct harmful effects on the heart and circulation, and that neurohormonal activation is now understood as one of the most important mechanisms in the progression of heart failure. Persistent sympathetic stimulation increases myocardial oxygen demand, provokes arrhythmias and is toxic to cardiac myocytes over time. Persistent angiotensin II and aldosterone increase afterload through vasoconstriction, expand blood volume beyond what the ventricle can handle and directly promote fibrosis in the heart and vessels. The body's rescue becomes the disease's engine.

The body does have a counterweight. When the ventricular walls are stretched, myocytes release natriuretic peptides, including B-type natriuretic peptide, which promote sodium excretion and vasodilation and oppose the renin-angiotensin-aldosterone system (Grossman & Porth, 2014). Heart failure swamps this counterweight, yet the peptides keep their value as a diagnostic marker, since their levels rise with wall stress (Murphy et al., 2020).

Ventricular Remodeling

Remodeling is the change in the size, shape and function of the ventricle that follows injury and sustained neurohormonal activation. At the cellular level, surviving myocytes hypertrophy, and some die through necrosis and programmed cell death. Fibroblasts lay down collagen between the myocytes, stiffening the wall and disrupting electrical conduction. At the level of the chamber, the ventricle dilates and becomes more spherical. A dilated, spherical ventricle has higher wall stress, which increases oxygen demand and further stimulates hypertrophy and neurohormonal activation, and the stretching of the mitral valve ring can cause the valve to leak, adding to the volume load (Hartupee & Mann, 2017). Each change worsens the others. Murphy et al. (2020) describe progressive left ventricular dilation and adverse remodeling as defining features of HFrEF, which is why therapies that slow or partially reverse remodeling have become central to treatment.

Why the Mechanism Changes the Goal of Care

Understanding remodeling changes what counts as success. For decades, heart failure treatment aimed at making patients feel better by removing fluid and strengthening contraction, and drugs that increased contractility seemed logical. Yet drugs that simply whip a failing heart harder tend to raise oxygen demand and, in the long run, have not improved survival, because they do nothing to interrupt the neurohormonal cycle (Hartupee & Mann, 2017). The shift to blocking that cycle explains a pattern that puzzles patients: a beta-blocker that slows the heart and may make them feel more tired in the first weeks is one of the drugs most likely to help them live longer. It also explains why stopping a medication because a patient "feels fine" can be harmful, since the benefit lies in slowing a process the patient cannot feel. For the nurse, this means that the goal of each hospital stay is not only to relieve congestion but to leave the patient on the medications that slow remodeling, at doses they can tolerate, with a plan for increasing them.

The stage framework reinforces this goal. Moving a patient from stage C back toward stability is rarely possible in a single admission, but preventing progression to stage D is a realistic aim, and much of that work happens in the weeks after discharge, when doses are adjusted and patients learn to manage their own symptoms (Heidenreich et al., 2022). The mechanism thus links the bedside to the clinic: every potassium checked, every weight recorded and every dose given on time is part of a long effort to slow a disease that the body itself keeps driving.

Signs and Symptoms Explained by Mechanism

The clinical picture of HFrEF follows from two consequences of the mechanism: congestion, from fluid retained behind a failing pump, and low output, from inadequate forward flow. When the left ventricle cannot empty, pressure rises in the left atrium and pulmonary veins, and fluid moves into the lungs. The patient becomes short of breath with exertion, then lying flat, then at night, and crackles can be heard at the lung bases. When the right ventricle fails, often as a result of left-sided failure, pressure backs up into the systemic veins, producing jugular venous distention, an enlarged and tender liver and swelling of the legs and abdomen (Grossman & Porth, 2014).

Weight gain is the earliest measurable sign of retention, because several liters of fluid can accumulate before edema or breathlessness becomes obvious. Low output explains fatigue, exercise intolerance, cool extremities and, in advanced disease, confusion and reduced urine output. The sympathetic response explains the resting tachycardia and the arrhythmias seen on telemetry. An S3 gallop, heard early in diastole, signals blood rushing into an enlarged, stiff ventricle. For the nurse, the value of this framework is that each finding has a cause, so a change in a finding has a meaning.

Treatment Explained by Mechanism

Current treatment of HFrEF is aimed less at making the weak heart pump harder than at interrupting the neurohormonal cycle that drives remodeling. The 2022 guideline recommends four classes of guideline-directed medical therapy for patients with symptomatic HFrEF, with diuretics added as needed to relieve congestion (Heidenreich et al., 2022).

Renin-angiotensin system inhibition comes first. An angiotensin receptor-neprilysin inhibitor combines an angiotensin receptor blocker with a drug that prevents the breakdown of natriuretic peptides, so it both blocks angiotensin II and strengthens the body's own counterweight; the guideline favors it over the older ACE inhibitors and angiotensin receptor blockers when a patient can take it (Heidenreich et al., 2022). Evidence-based beta-blockers blunt the toxic effects of chronic sympathetic stimulation, slow the heart rate and, over months, allow partial reversal of remodeling. Mineralocorticoid receptor antagonists, such as spironolactone, block aldosterone's effects on sodium retention and fibrosis. Each of these classes acts directly on a mechanism described above, which is why they reduce mortality rather than only relieving symptoms (Murphy et al., 2020).

The fourth class, sodium-glucose cotransporter 2 inhibitors, was developed for diabetes. In the trial that established its role, McMurray et al. (2019) randomly assigned 4,744 patients with HFrEF whose symptoms ranged from mild to severe to dapagliflozin or placebo on top of the therapy they already received. Over a median of 18.2 months, the composite of worsening heart failure or cardiovascular death occurred in 16.3% of the dapagliflozin group and 21.2% of the placebo group, and the results were similar in patients with and without diabetes. The mechanisms are still being clarified but include promoting sodium and glucose excretion by the kidney and favorable effects on cardiac metabolism and loading conditions.

Loop diuretics, such as furosemide, remove the retained sodium and water and relieve congestion quickly, but they do not slow the disease, and they can activate the renin-angiotensin-aldosterone system further if volume is depleted. They are given at the lowest dose that keeps the patient free of congestion (Heidenreich et al., 2022).

Nursing Assessment and Monitoring

The mechanism turns each routine on the telemetry unit into a purposeful check. Daily weights, taken each morning on one scale, once the bladder is emptied and before the patient eats, are the most sensitive bedside measure of sodium and water retention. Intake and output records show whether diuresis is working. Lung sounds, jugular venous pressure and peripheral edema track congestion, while mental status, skin temperature and urine output track forward flow.

Laboratory monitoring follows the drugs' effects. Renin-angiotensin system inhibitors and mineralocorticoid receptor antagonists can raise potassium and creatinine, while loop diuretics lower potassium and magnesium, and a falling potassium makes the ectopy on the monitor more likely. Nurses therefore check the potassium and creatinine before giving these medications and report changes promptly. Heart rate and blood pressure are checked before beta-blockers and vasodilating drugs, since symptomatic bradycardia or hypotension may require holding a dose or adjusting a plan, and new symptoms during dose increases are reported rather than tolerated silently. On telemetry, an increase in ectopic beats or a new atrial fibrillation may reflect electrolyte shifts, stretch of the atria or sympathetic activation, each of which has its own response.

A brief example shows how the mechanism guides judgment. A patient whose weight has risen 1.5 kg overnight, with new crackles and a heart rate of 108, is retaining fluid and activating sympathetic compensation; the nurse reports the trend, anticipates a diuretic adjustment and watches potassium closely once diuresis begins. The same weight gain in a patient whose blood pressure is falling and whose urine output has dropped may signal worsening forward flow, which calls for urgent evaluation rather than a routine diuretic dose.

Self-Care Teaching

Hospital care for heart failure lasts days; self-care lasts the rest of the patient's life. Riegel et al. (2017), in an American Heart Association statement, describe self-care as a decision-making process with three elements: maintenance, which includes taking medications and following a diet and activity plan; monitoring, which includes watching for symptoms and weight changes; and management, which includes responding to those changes. They report strong evidence that self-care helps patients reach the goals of the treatment plan.

Jaarsma et al. (2021) offer practical recommendations for heart failure self-care, including symptom monitoring, medication adherence, nutrition, physical activity, sleep and preventing infections through immunization. Teaching is more effective when it explains the mechanism in plain language. A patient told that the kidneys hold onto salt and water when the heart is weak, and that the scale shows that water before the lungs do, has a reason to weigh every morning and to call when the weight climbs quickly. A patient who understands that the beta-blocker protects the heart over months, even if it makes them feel more tired at first, is more likely to keep taking it. The best answer to the patient's question about the morning weight is the mechanism itself, put into everyday words.

Conclusion

HFrEF begins with an injury that lowers cardiac output and progresses largely because of the body's own responses. Sympathetic and renin-angiotensin-aldosterone activation preserve perfusion at first but, sustained, cause fluid retention, vasoconstriction, myocyte loss, fibrosis and dilation, a self-reinforcing cycle of remodeling. The signs a telemetry nurse assesses, from crackles and edema to weight gain and tachycardia, are expressions of that cycle, and the drugs that improve survival work by interrupting it. For nurses, understanding the mechanism changes routine tasks into informed judgments and gives patients reasons, not just rules, for the self-care that will determine how they live with the disease.

References

Grossman, S. C., & Porth, C. M. (2014). Porth's pathophysiology: Concepts of altered health states (9th ed.). Wolters Kluwer Health/Lippincott Williams & Wilkins.

Hartupee, J., & Mann, D. L. (2017). Neurohormonal activation in heart failure with reduced ejection fraction. Nature Reviews Cardiology, 14(1), 30-38. https://doi.org/10.1038/nrcardio.2016.163

Heidenreich, P. A., Bozkurt, B., Aguilar, D., Allen, L. A., Byun, J. J., Colvin, M. M., Deswal, A., Drazner, M. H., Dunlay, S. M., 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. https://doi.org/10.1161/CIR.0000000000001063

Jaarsma, T., Hill, L., Bayes-Genis, A., La Rocca, H. B., Castiello, T., Čelutkienė, J., Marques-Sule, E., Plymen, C. M., Piper, S. E., Riegel, B., Rutten, F. H., Ben Gal, T., Bauersachs, J., Coats, A. J. S., Chioncel, O., Lopatin, Y., Lund, L. H., Lainscak, M., Moura, B., . . . Strömberg, A. (2021). Self-care of heart failure patients: Practical management recommendations from the Heart Failure Association of the European Society of Cardiology. European Journal of Heart Failure, 23(1), 157-174. https://doi.org/10.1002/ejhf.2008

McMurray, J. J. V., Solomon, S. D., Inzucchi, S. E., Køber, L., Kosiborod, M. N., Martinez, F. A., Ponikowski, P., Sabatine, M. S., Anand, I. S., Bělohlávek, J., Böhm, M., Chiang, C. E., Chopra, V. K., de Boer, R. A., Desai, A. S., Diez, M., Drozdz, J., Dukát, A., Ge, J., . . . Langkilde, A. M. (2019). Dapagliflozin in patients with heart failure and reduced ejection fraction. New England Journal of Medicine, 381(21), 1995-2008. https://doi.org/10.1056/NEJMoa1911303

Murphy, S. P., Ibrahim, N. E., & Januzzi, J. L. (2020). Heart failure with reduced ejection fraction: A review. JAMA, 324(5), 488-504. https://doi.org/10.1001/jama.2020.10262

Riegel, B., Moser, D. K., Buck, H. G., Dickson, V. V., Dunbar, S. B., Lee, C. S., Lennie, T. A., Lindenfeld, J., Mitchell, J. E., Treat-Jacobson, D. J., & Webber, D. E. (2017). Self-care for the prevention and management of cardiovascular disease and stroke: A scientific statement for healthcare professionals from the American Heart Association. Journal of the American Heart Association, 6(9), e006997. https://doi.org/10.1161/JAHA.117.006997