Pathophysiology of Heart Failure - Pathology - ATOT

Topic: Heart failure
Faculty: Pathology
Course: BSc ATOT- 2nd year

- Intro
- Types
- Causes
- Pathogenesis
- Mechanism of heart failure

1. Pathophysiology of Heart Failure Dr. Salman Ansari Dept. of Pathology Kanachur Institute of Medical Sciences

2. Contents Intro Types Causes Pathophysiology

3. Heart Failure Old term: Congestive Heart Failure Definition: Progressive condition in which the heart is not able to pump blood at a rate sufficient to meet the metabolic demands of the peripheral tissue Decreased cardiac output, increased congestion

4. Types of heart failure Depending of onset : Chronic heart failure : gradual development of HF Acute heart failure : sudden development of HF

5. Depending on output : Systolic dysfunction : decrease in Ejection Fraction(EF) Diastolic dysfunction : inability of heart chamber to expand and fill sufficiently during diastole Left- or right-sided HF

6. Causes of heart failure Left-sided heart failure Right-sided heart failure Ischemic heart disease(IHD) - Most common cause Hypertension Aortic and mitral valve disorders Myocardial diseases Right-sided valvular heart disease Lung disorders such as: Emphysema Chronic bronchitis Pulmonary hypertension

7. Pathogenesis of heart failure Takes time for congestive heart failure to develop, as heart has the ability to compensate with various mechanisms These compensatory mechanisms maintain cardiac output by increasing diastolic ventricular filling pressure and end-diastolic volume Mechanisms include: Frank-Starling mechanism(or Starling’s Law) Myocardial hypertrophy Activation of neurohumoral system

8. Release of norepinephrine Activation of RAA system Release of ANP

9. Frank-Starling mechanism(or Starling’s Law) : the greater the volume of blood flowing into the ventricle, more is the stretching of the walls of the heart and more is the force of contraction of the heart Myocardial hypertrophy : chamber may or may not dilate Activation of neurohumoral system : to increase heart function by regulating filling volume and pressure

10. Release of norepinephrine : increases heart rate, myocardial contraction and vascular resistance Activation of renin-angiotensin-aldosterone system : Decreased EF → decreased blood supply to kidney → activation of RAAS → retention of salt and water → increased fluid volume Release of Atrial Natriuretic Peptide(ANP) : tries to lower blood pressure in response to RAAS, but ultimately is unable to

11. Mechanism of heart failure LVF/RVF → Reduced cardiac output ↓ Compensatory mechanisms : Neurohumoral system Cardiac compensatory mechanisms

12. Activation of RAAS : Causes sodium and water retention ↓ Increased intravascular volume Sympathetic nervous system : Causes vasoconstriction Increased blood pressure and cardiac workload ↓ Further stress on myocardium ↓ CONGESTIVE HEART FAILURE Neurohumoral activation

13. Tachycardia and increased myocardial contractility ↓ Increased cardiac workload ↓ Compensatory hypertrophy and dilatation 2) Cardiac compensatory mechanisms

14. References: Dr. Ramadas Nayak - Textbook of Pathology for Allied Health Sciences Questions: [email protected]