Cardiac lecture 5: Valvular Diseases

Cardiac Lecture 5: Valvular Diseases

Objectives

• Overview of the heart as a pump

• Understanding heart valves and their functions

• Terminology related to murmurs and turbulent flow

• Insights into valvular heart disease, including risk factors, symptoms, and management

The Heart as a Pump

• The heart functions as a pump with valves regulating unidirectional blood flow.

• Key Point: Valves open/close in response to pressure differentials, not muscular action.

Heart Valves

1. Tricuspid Valve

   • Location: Between the right atrium and right ventricle

   • Function: Prevents backflow into the right atrium.

2. Pulmonic Valve

   • Location: Between the right ventricle and pulmonary artery

   • Function: Prevents backflow into the right ventricle.

3. Mitral Valve

   • Location: Between left atrium and left ventricle

   • Function: Prevents backflow into the left atrium during ventricular contraction.

   • Structure: Has two leaflets (anterior and posterior).

4. Aortic Valve

   • Location: Between left ventricle and aorta

   • Function: Prevents backflow into the left ventricle after blood is ejected into systemic circulation.

   • Structure: Typically has three leaflets.

• Pressure Dynamics:

  • Blood moves from high to low pressure.

  • Valves open when upstream pressure > downstream pressure.

Understanding Murmurs

• Definition: A murmur is turbulent blood flow that can be heard with a stethoscope.

  • Analogy: Like feeling a shudder in a kinked garden hose; turbulence can produce sound.

• Loud Murmurs: Not necessarily worse than quiet murmurs; they may indicate varying degrees of underlying issues.

Types of Valve Disorders

1. Stenosis

   • Definition: When a valve is stuck shut and does not open normally.

   • Consequence: Reduced blood flow due to narrowed valve openings.

2. Insufficiency / Regurgitation

   • Definition: A leaking valve that does not close completely.

   • Consequence: Blood leaks backward, causing the heart to work harder.

3. Common Terminology:

   • Aortic Stenosis

   • Aortic Insufficiency / Regurgitation (same)

   • Mitral Stenosis

   • Mitral Insufficiency / Regurgitation (same)

   • Each may vary in severity and underlying causes.

Mitral Valve Complexity

• Analogy of Train Tunnel and Parachutes:

  • Parachutes represent valve leaflets; if not properly positioned (due to various conditions), it can lead to leaks.

• Causes leading to leaks:

  • Enlarged structures, broken chordae tendineae, muscle loosening, or diseases affecting the valve structure.

Valvular Heart Disease Overview

• Definition: Damage or defects in one or more heart valves.

• Common Valves Affected: Mitral and aortic.

• Pathophysiology: Proper valve function is vital for unidirectional blood flow during contraction and relaxation phases of the heart.

Two Key Problems from Valve Damage:

1. Stenosis

   • Thickened, stiff leaflets; narrowing opening. Can strain the heart as it pumps harder.

2. Regurgitation

   • Leaflets fail to close completely, allowing backflow.

Risk Factors for Valvular Disorders

• Advancing Age

• High Blood Pressure

• Coronary Artery Disease

• History of Heart Attacks

• Heart Failure or Arrhythmias

• Rheumatic Fever

• Infective Endocarditis

• Congenital Defects

Symptoms of Valve Disorders

1. Mitral Valve Stenosis Symptoms:

   • Dyspnea on exertion

   • Hemoptysis

   • Fatigue

   • Atrial fibrillation noted via EKG

   • Palpitations

   • Loud accentuated S1 sound

   • Low-pitched rumbling diastolic murmur

2. Mitral Valve Regurgitation Symptoms:

   • Acute: New systolic murmur, pulmonary edema, rapidly progressing cardiogenic shock.

   • Chronic: Weakness, fatigue, exertional dyspnea, palpitations, S3 gallop, holosystolic murmur.

3. Aortic Valve Stenosis Symptoms:

   • Angina

   • Syncope

   • Dyspnea on exertion

   • Heart failure

   • Normal or soft S1 sounds

   • Diminished/absent S2 sounds

   • Systolic murmur and prominent S4.

4. Aortic Valve Regurgitation Symptoms:

   • Acute: Abrupt dyspnea, chest pain, left ventricular failure, cardiogenic shock.

   • Chronic: Fatigue, exertional dyspnea, orthopnea, paroxysmal nocturnal dyspnea, water-hammer pulse, heaving precordial impulse, diminished/absent S1, S3/S4 sounds, soft high-pitched diastolic murmur.

Patient Assessment for Valvular Diseases

• Subjective Data:

  • History of rheumatic fever or infective endocarditis

  • Prior heart disease or congenital defects

  • Inability to perform activities of daily living (ADLs) without fatigue/weakness

  • Chest pain details (quality, duration, onset, triggers, relief)

  • Complaints of palpitations, lightheadedness, dizziness, fainting, weight gain, dyspnea, nocturnal dyspnea, orthopnea.

• Objective Data:

  • Heart murmurs:

    • Assess presence and character of adventitious breath sounds (e.g., crackles, wheezing) and any pericardial rubs.

    • Inspect for edema, noting if pitting or non-pitting.

  • Diagnostic Exams:

    • Echocardiogram is the primary tool for diagnosing valvular disease.

    • May be discovered incidentally during cardiac cath or MRIs.

Medical Management of Valvular Disease

• Prescriptive measures may include:

  • Activity limitations

  • Sodium-restricted diets

  • Education on diuretics, digoxin, antiarrhythmics

  • Surgical interventions when necessary:

    • Transcatheter Aortic Valve Replacement (TAVR):

      • Minimally invasive procedure for severe aortic stenosis (high-risk surgical candidates).

      • Risks: vascular injury, paravalvular leak, pacemaker need.

  • Valve Replacement:

    • Open-heart surgery to remove and replace diseased valves (mechanical vs. bioprosthetic).

    • Candidates: younger, healthier patients with benefits of long-term valve durability.

  • Open Mitral Commissurotomy:

    • Procedure for mitral stenosis; suitable for younger patients with pliable valves.

    • Advantages include preservation of the patient’s valve.

    • Not suitable if the valve is heavily calcified or regurgitant.

Nursing Interventions and Patient Education

• Nursing Interventions:

  • Assist with ADLs

  • Manage decreased cardiac output symptoms

  • Administer medications (diuretics, digoxin, antiarrhythmics)

  • Evaluate vital signs and change from baseline assessment.

  • Monitor oxygen therapy, fluid balance, daily weights, edema, and peripheral perfusion.

• Patient Teaching:

  • Medication adherence and dietary management (low sodium diet)

  • Importance of activity limitations to conserve energy

  • Explain the disease process and symptoms that require reporting

  • Emphasize antibiotic prophylaxis prior to invasive procedures and maintaining good oral hygiene.

  • Be aware of anticoagulant therapy needs depending on surgical intervention and valve type.

Prognosis

• Varies by the severity of the condition and individual circumstances.

• Post-surgical prognosis for affected valves is generally fair to good, with improvement in symptoms but potential for persistent abnormalities.

Key Points Summary

• Understand the differences between stenosis and regurgitation of heart valves.

• Recognize common risk factors for heart valve disease.

• Familiarize yourself with the necessary assessment data for valvular diseases.

• Master nursing interventions including medication administration, monitoring, and education on dietary and lifestyle modifications.