Congestive Cardiac Failure or Congestive Heart Failure (CHF)- B. Pharma 2nd Semester Pathophysiology notes pdf

Congestive Cardiac Failure of Congestive Heart Failure (CHF)

Contents

•       Congestive Cardiac Failure

•       Types

•       Pathogenesis

Objectives  

At the end of this PDF Notes, student will be able to

•       Define  congestive heart failure

•       Discuss the types of congestive heart failure

•       Explain the pathophysiology of congestive heart failure

•       Discuss the signs and symptoms of it

CONGESTIVE CARDIAC FAILURE

•       A clinical syndrome

•       Result from any disorder that impairs the ability of the ventricle to fill with or eject blood

•       Rendering the heart unable to pump blood at a rate sufficient to meet the metabolic demands of the body

•       Heart failure can result from any disorder that reduces ventricular filling (diastolic dysfunction) and/or myocardial contractility (systolic dysfunction)

Etiology of Congestive Heart Failure

Systolic dysfunction (decreased contractility)

•       Reduction in muscle mass (e.g. myocardial infarction)

•       Dilated cardiomyopathies

•       Ventricular hypertrophy

•       Pressure overload (e.g. systemic or pulmonary    HT, aortic or pulmonic valve stenosis)

•       Volume overload (e.g., valvular regurgitation, shunts, high-output states)

Diastolic dysfunction (restriction in ventricular filling)

•       Increased ventricular stiffness

•       Ventricular hypertrophy (e.g. hypertrophic cardiomyopathy)

•       Infiltrative myocardial diseases (e.g. amyloidosis, sarcoidosis, endomyocardial fibrosis)

•       Myocardial ischemia and infarction

•       Mitral or tricuspid valve stenosis

•       Pericardial disease (e.g. pericarditis, pericardial tamponade)

Types of Heart Failure

•       Acute and chronic heart failure

•       High output and low output HF

•       Left sided, right sided and biventricular HF

•       Forward and backward HF

•       Systolic and diastolic HF 

Acute heart failure 

•       Heart is not able to pump the blood effectively

•       Also called as Decompensated heart failure

•       Compensatory mechanisms  of human body cause increase in CO by stimulation of β₁  receptors and  also RAA-system

•       Both mechanism leads to vasoconstriction

•       Treatment with Inotropic drugs becomes necessary

Chronic heart failure

•       Failure of compensatory mechanism

•       Heart needs to undergo surgery for its repair

•       Further controlled by administration of drugs

High output HF:

•       There is high demands of the body, which are not met even with increased cardiac output

•       e.g.: anemia, pregnancy

Low output HF:

•       There is decreased contractility of heart leading to decreased cardiac output

•       e.g.: cardiomyopathy, valvular disease

Left sided (left ventricular) HF

•        Excess fluid accumulates upstream

•        Reduction in left ventricular output

•        Increase in left atrial pressure

•        Increase in pulmonary venous pressure

Ø  Acute increase in left atrial pressure causes pulmonary congestion and pulmonary edema e.g.: MI

Ø   Gradual increase in left atrial pressure causes reflex pulmonary hypertension but no pulmonary edema

e.g. : aortic stenosis

Right sided (right ventricular) HF:

•         Excess fluid accumulates upstream behind the failing right ventricle  

•         Reduction in right ventricular output

•         Results in systemic venous congestion

   Ex: pulmonary valvular stenosis, multiple pulmonary emboli 

Systolic HF:

•       Characterized by an abnormality of ventricular contraction

•       As seen in ischemic heart failure and dilated cardiac myopathy

Diastolic HF:

•       Characterized by an impaired ventricular relaxation

•       Increased ventricular stiffness resulting in diastolic dysfunction

e.g.: ischemia, left ventricular hypertrophy

Pathophysiology of Congestive Heart Failure

Preload: Pressure that fills the left ventricle during diastole

•       Main Determinant- left ventricular compliance and venous return

•       Small increase in end-diastolic volume

•       large increase in cardiac output

•       Primary compensatory mechanism in normal heart

•       Ability of heart to alter the force of contraction depends  on preload

Afterload: Pressure against which the left ventricular contracts and is measured as the mean aortic pressure 

• Main determinants - total peripheral resistance and left ventricle size 
• Left ventricular dysfunction - an inverse relationship exist between afterload and stroke volume
• An increase in afterload causes a decrease in stroke volume

Key components of the pathophysiology of cardiac remodelling

Compensatory Mechanisms

Cardiac compensatory mechanism:

Ø  Ventricular dilation

Ø  Ventricular hypertrophy

Peripheral compensatory mechanisms:

Ø  Increased sympathetic activity

Ø  Activation of renin angiotensin aldosterone system

Ø   Increased release of arginine vasopressin

Renin Angiotensin Aldosterone system

Clinical Presentation – Signs of Congestive Heart Failure

•       Pulmonary edema

•        Pleural effusion

•        Tachycardia

•        Cardiomegaly

•       Peripheral edema

•        Jugular venous distension

•        Hepatojugular reflux

•        Hepatomegaly

Symptoms of Congestive Heart Failure

•          Dyspnea

•       Orthopnea

•       Paroxysmal nocturnal dyspnea

•        Exercise intolerance

•        Tachypnea

•       Ascites, Mental status changes

•       Cough

•        Fatigue

•        Nocturia

•        Hemoptysis

•        Abdominal pain, Anorexia, Nausea, Bloating

SUMMARY

•       CHF is a clinical syndrome that impairs the ability of the ventricle to fill with or eject blood

•       Heart is unable to pump blood at a rate sufficient to meet the metabolic demands of the body

•       It can be classified as:  Acute and chronic heart failure,

•       High output and low output heart failure,

•       Left sided, right sided and biventricular heart failure,

•       Systolic and diastolic heart failure