Alterations in Cardiovascular Function: Heart Failure Study Notes

Alterations in Cardiovascular Function: Heart Failure - RNSG 1441 Common Concepts of Adult Health

Learning Outcomes

• Identify major risk factors and clinical manifestations associated with fluid imbalances.
• Describe the impact of disrupted fluid balance on perfusion, oxygenation, and overall client stability.
• Apply clinical judgment to prioritize nursing interventions for clients with fluid volume excess or fluid volume deficit.
• Explain the foundational anatomy and physiology of the cardiovascular system as it relates to perfusion and cardiac output.
• Differentiate the clinical presentation of heart failure and cardiomyopathy, including key assessment findings and indicators of worsening status.
• Apply clinical judgment to develop prioritized care plans for clients with alterations in cardiovascular function such as heart failure and cardiomyopathy.

Cardiac Anatomy & Physiology

Overview

• The heart functions as a muscular pump that maintains circulation and tissue perfusion.
• Adequate cardiac function is necessary to:
  • Deliver oxygen and nutrients to tissues.
  • Remove metabolic waste.
  • Maintain adequate blood pressure.

Cardiac Anatomy

• The heart consists of four chambers and four valves that work collectively to maintain one-way blood flow.
  • Four chambers:
  • Right atrium
  • Right ventricle
  • Left atrium
  • Left ventricle
  • Chambers contract in response to electrical impulses.
• Four valves:
  • Tricuspid
  • Pulmonic
  • Mitral
  • Aortic
  • Valves open and close in reaction to pressure changes, rather than muscular contraction.

Cardiac Blood Flow

• Blood flow sequence:
  • Deoxygenated blood enters the right atrium, then flows into the right ventricle.
  • Blood moves to the pulmonary circulation for gas exchange.
  • Oxygenated blood returns to the left atrium, then to the left ventricle.
  • Blood is finally ejected into arterial circulation.

Cardiac Cycle

• The cardiac cycle comprises two key phases:
  • Systole: Ventricles contract and eject blood.
  • Diastole: Ventricles relax and fill.
  • Blood pressure readings reflect:
  • Systolic: Maximum pressure during contraction.
  • Diastolic: Minimum pressure during relaxation.
• Heart sounds arise from valve closure:
  • S1: Closure of AV valves.
  • S2: Closure of semilunar valves.
  • Alterations in valve closure can lead to murmurs or extra heart sounds.

Hemodynamics: Cardiac Output

• Cardiac output (CO) is the volume of blood the heart pumps per minute (liters/minute).
  • CO can be seen as adjustable levers that maintain activity.
• Components affecting cardiac output include:
  • Heart rate
  • Stroke volume
  • Stroke volume components:
  • Preload: Volume of blood in the ventricle before contraction. Increased by fluid volume excess, valve regurgitation, initially increases stroke volume but can lead to congestion.
  • Afterload: Resistance against which the ventricle must pump. Increased by hypertension and vasoconstriction, it elevates myocardial oxygen demand and can decrease stroke volume if too high.
  • Contractility: The strength of myocardial contraction, influenced by oxygen, electrolytes, and myocardial integrity. Reduced contractility decreases stroke volume and cardiac output, common in systolic heart failure.
  • Increased contractility occurs with sympathetic stimulation but raises oxygen demand.

Compensation Mechanisms

• When cardiac output diminishes, the following may occur:
  • Blood pressure decreases.
  • Organs receive less oxygen.
  • Neurohormonal compensatory mechanisms activate, leading to:
  • Increased heart rate.
  • Fluid retention.
  • Cardiac remodeling.
  • While these mechanisms may temporarily preserve perfusion, they increase cardiac workload and fluid burden, worsening heart failure over time.

Fluid Volume Balance

Overview & Relevance to Nursing

• Fluid balance is crucial for:
  • Maintaining blood pressure.
  • Supporting cardiac output.
  • Ensuring adequate tissue perfusion.
• Nurses significantly contribute by recognizing early signs of fluid imbalance through:
  • Monitoring vital signs.
  • Assessing weight trends.
  • Tracking intake and output.
  • Performing physical assessments.

Body Fluid Compartments

• Total body water constitutes approximately half of an adult’s body weight, divided into:
  • Intracellular fluid (ICF):
  • Approximately ⅔ of total body water, located inside cells, not circulating.
  • Extracellular fluid (ECF):
  • Interstitial fluid between cells and intravascular (plasma) fluid.
  • Intravascular fluid directly impacts blood pressure and cardiac preload.

Hydrostatic vs. Osmotic Pressure

• Hydrostatic pressure (PUSH):
  • Forces fluid out of blood vessels, prevalent in arterial circulation.
• Osmotic pressure (PULL):
  • Pulls fluid into blood vessels, driven by plasma proteins.
• The balance between hydrostatic and osmotic pressures determines:
  • Edema formation.
  • Effective circulating volume.

Role of Electrolytes

• Electrolytes and plasma proteins dictate fluid distribution.
• Sodium concentration alterations affect water movement, specifically pulling fluid into intravascular spaces, thereby increasing preload.

Hormonal Regulation of Fluid Balance

• Antidiuretic hormone (ADH):
  • Encourages renal water reabsorption.
• Renin–angiotensin–aldosterone system (RAAS):
  • Promotes sodium and water retention and activates during states of decreased perfusion, contributing to fluid retention when cardiac output is compromised.

Fluid Balance and Perfusion

• Adequate fluid volume is essential for:
  • Filling the heart.
  • Maintaining preload.
  • Supporting cardiac output.
• Effects of wrongful fluid balance:
  • Fluid deficit leads to hypotension and shock.
  • Fluid excess results in congestion and pulmonary edema.

Clinical Management of Fluid Volume

• Patients with hemodynamic impairment require meticulous assessment of fluid volume.
• Treatment primarily aims to reduce fluid volume while being cautious of overcorrection, intending for:
  • Normotension.
  • Clear lung sounds.
  • Normal heart rate.
  • Minimal to no swelling.
  • Stable weight.

Heart Failure

Overview & Relevance to Nursing

• Heart failure (HF) is a clinical syndrome wherein the heart fails to pump sufficient blood to meet bodily needs, leading to:
  • Decreased cardiac output.
  • Compromised tissue perfusion.
  • Compensatory fluid retention.
• Heart failure is commonly implicated in:
  • Hospitalizations.
  • Respiratory distress.
  • Fluid volume excess.
• Nurses play a vital role in the early identification and ongoing management through diligent assessment.

Pathophysiology of Heart Failure

• HF arises from reduced cardiac output due to:
  • Impaired contractility.
  • Impaired filling.
  • Increased workload.
• Reduced cardiac output results in:
  • Decreased organ perfusion.
  • Compensatory mechanisms activation, which can initially support perfusion but ultimately exacerbate heart failure.

Risk Factors

• Key risk factors for heart failure include:
  • Hypertension.
  • Coronary artery disease/myocardial infarction (MI).
  • Cardiomyopathy.
  • Valvular heart disease.
  • Diabetes mellitus.
  • Chronic kidney disease.
  • Increased prevalence with aging.

Impact on Overall Health

• Heart failure is progressive and typically not reversible, characterized by:
  • Increasing exacerbations.
  • Chronic symptoms such as dyspnea, fatigue, weakness, and edema, which diminish quality of life and activity tolerance.
• Client education necessities include:
  • Self-monitoring.
  • Recognition of critical changes in condition.
  • Adjustments in lifestyle.
  • Medication education.

Clinical Presentation

• Left-Sided Heart Failure:
  • Pulmonary congestion; dyspnea; orthopnea; paroxysmal nocturnal dyspnea; crackles (rales); productive cough (white or pink blood-tinged sputum); jugular vein distention (JVD); shortness of breath; weight gain; increased abdominal girth.
• Right-Sided Heart Failure:
  • Systemic congestion; peripheral edema; ascites; hepatomegaly/splenomegaly; generalized swelling; chest discomfort; palpitations; S3 heart sounds; murmurs.

Lab Testing & Diagnostic Studies

• Diagnostic tests assess severity, contributing factors, and treatment response.
  • Complete Metabolic Profile (CMP):
  • Evaluates renal and liver function, electrolytes, anemia, and iron deficiency.
  • B-type Natriuretic Peptide (BNP):
  • Differentiates cardiac from non-cardiac dyspnea; levels elevate with ventricular stretch and fluid overload, helping to monitor treatment response.
  • Higher levels correlate with increased severity, readmission risk, and mortality.
  • Echocardiogram:
  • Primary diagnostic tool for HF assessing left ventricular ejection fraction (EF), wall motion abnormalities, and valve function.
  • Chest X-Ray:
  • Can display cardiomegaly, pulmonary vascular congestion, and fluid in lung bases.
  • Other diagnostic tests may include ECG, stress testing, and cardiac catheterization.

Client Education Heart Failure

• Stress the criticalness of daily self-monitoring, especially regarding:
  • Weight fluctuations.
  • Shortness of breath.
  • Swelling.
• Instruct clients to log weight daily under consistent conditions:
  • Same scale and time, preferably in the morning before eating.
• Advise reporting weight gain of:
  • 2–3 lbs in one day.
  • 5 lbs in one week.

Lifestyle & Self-Management

• Vital lifestyle modifications:
  • Smoking cessation.
  • Limit alcohol consumption.
• Preload reduction strategies:
  • Sodium restriction between 1500-2000 mg/day.
  • Fluid restriction of approximately 2L/day for patients with advanced symptoms or hyponatremia.
• Reinforce:
  • Medication adherence.
  • Follow-up appointments.
  • Necessary vaccinations (influenza, pneumococcal).

Sodium Intake

• Processed and packaged foods are typically high in sodium.
• Common sources to educate patients on include:
  • Lunch meats.
  • Canned soups.
  • Cheeses.
  • Frozen meals.
  • Commercially prepared foods.
• Encourage clients to read food labels for hidden sodium.

Nonpharmacological Interventions

• Cornerstones of heart failure management include:
  • Smoking cessation.
  • Weight management if necessary.
  • Monitoring fluid intake.
  • Sodium restriction.
  • Limiting alcohol and caffeine.
  • Following a heart-healthy diet.
  • Engaging in regular physical activity as tolerated.
  • Maintaining blood pressure control.

Pharmacological Interventions

• Multi-faceted medication therapy commonly includes:
  • Diuretics:
  • (e.g., Furosemide): For preload reduction, congestion, and edema alleviation.
  • ACE Inhibitors:
  • (e.g., Lisinopril): For afterload reduction, easing cardiac workload.
  • Beta-blockers:
  • (e.g., Metoprolol): Neurohormonal reduction, preventing remodeling, and decreasing mortality.
  • SGLT-2 Inhibitors:
  • (e.g., Dapagliflozin): Reducing hospitalization risks.

Surgical & Device-Based Interventions

• Used when heart failure results from structural issues, ischemia, or dysrhythmias:
  • Cardiac Catheterization / PCI:
  • Employed for HF stemming from acute MI to restore perfusion and limit myocardial damage.
  • Implantable Cardioverter-Defibrillator (ICD):
  • Indicated for patients with low ejection fractions who are at high risk of lethal dysrhythmias, helping reduce the risk of sudden cardiac death.

Treatments & Therapies

• Goals include reducing preload through:
  • Diuretics and sodium-restricted diets.
• Lowering afterload by utilizing:
  • Vasodilators, like ACE-inhibitors, which lessen the pressure the heart must exert to pump.
• Modifying maladaptive compensatory mechanisms employing:
  • Beta-blockers and SGLT2 inhibitors.

Clinical Judgement: Heart Failure

• Recognize Cues:
  • Dyspnea, fatigue, and activity intolerance.
  • Weight gain, peripheral edema, JVD.
  • Crackles and S3 sounds, murmurs.
  • Elevated BNP levels, cardiomegaly.
• Analyze Cues:
  • Identify decreased cardiac output and fluid volume excess.
  • Observe for worsening indications such as rapid weight accumulation and increasing edema.
• Prioritize Hypotheses:
  • Impaired cardiac output.
  • Fluid volume excess.
  • Risk for impaired gas exchange.
• Generate Solutions:
  • Strategies to reduce preload for fluid overload.
  • Aid in oxygenation and perfusion.
  • Foster medication adherence and self-monitoring to prevent decompensation and re-hospitalizations.
• Take Actions:
  • Elevate head of bed (High-Fowler's position).
  • Administer O₂ as prescribed.
  • Encourage cough and deep breathing.
  • Regularly monitor lung sounds, weight, intake, and output.
  • Implement diuresis protocols.
  • Reinforce education regarding medications, diets, and daily weight monitoring.
• Evaluate Outcomes:
  • Assess improvements in breathing and oxygenation.
  • Expect stable or reduced weight and less edema.
  • Anticipate enhanced activity tolerance and no acute exacerbations or readmissions.

Cardiomyopathy

Overview

• Cardiomyopathy is a chronic condition that alters the structure and function of the heart muscle.
• This impairment affects both the heart’s ability to pump and fill effectively.
• Cardiomyopathy can be idiopathic or linked to specific factors and has the potential to progress over time, increasing the risk for heart failure and dysrhythmias.

Heart Failure vs. Cardiomyopathy

• Heart Failure:
  • A functional problem where the heart cannot meet bodily demands, characterized by decreased cardiac output, decreased perfusion, and fluid retention.
  • Can occur due to various conditions including hypertension, myocardial infarction, valvular disease, and cardiomyopathy.
• Cardiomyopathy:
  • A structural issue specifically affecting the heart muscle with abnormal size, shape, thickness, and stiffness.
  • Can ultimately lead to heart failure.

Types of Cardiomyopathy

• Dilated Cardiomyopathy (DCM):
  • Most prevalent type characterized by ventricular dilation and weakened contractions, leading to decreased cardiac output due to impaired systolic function. Frequently progresses to heart failure.
• Hypertrophic Cardiomyopathy (HCM):
  • Characterized by thickened left ventricular walls and septum, impairing ventricular filling and leading to decreased cardiac output due to diastolic dysfunction.
• Restrictive Cardiomyopathy (RCM):
  • Least common form often associated with poor prognosis, with stiff, non-mobile ventricles that severely impair diastolic filling, resulting in decreased cardiac output despite preserved contraction.

Risk Factors for Cardiomyopathy

• Genetic predisposition.
• Male gender (particularly for DCM).
• Viral or inflammatory processes.
• Chronic alcohol use.
• Drug use (methamphetamines, cocaine).
• Autoimmune disorders.
• Metabolic or endocrine disorders.
• Pregnancy.
• Chemotherapy exposure.

Clinical Presentation

• Common symptoms include:
  • Fatigue and reduced activity tolerance.
  • Exertional dyspnea.
  • Chest discomfort.
  • Palpitations.
  • Peripheral edema.
  • Episodes of syncope or near-syncope.
• As the disease advances, signs of heart failure appear with increased risk for dysrhythmias and sudden cardiac death, particularly salient in hypertrophic cardiomyopathy.

Disease Management & Clinical Judgement

• Management parallels strategies used for heart failure, focusing on symptom alleviation, disease progression prevention, and reducing complications and hospital admissions.
• Care encompasses similar clinical judgement frameworks as those used in heart failure management.