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HEART FAILURE

DR MBURU CLINICAL PHARMACIST 1 ST /DECEMBER/

The normal heart physiology

2

4

Introduction

• The aim of the CVS is to provide adequate

perfusion to all body organs and tissues.

• Cardiac output (CO) blood ejected per unit

time (L/min) is a measure of heart’s pump

performance and is a product of:

- CO = Heart Rate (HR) x Stroke volume (SV)

- Normal; 4 - 7L/min

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Intro

□ HR is controlled by autonomic nervous system □ SV i.e. volume ejected during systole (Normal; 60- 130mL) is determined by preload, afterload and myocardial contractility Preload;

• Is the amount of stretch on ventricle due to blood volume during venous return in diastole.
• It describes forces acting on the venous side of the circulation to affect myocardial wall tension.
• Peripheral venous dilation and↓ peripheral venous volume ↓ preload, and vice versa.

7

Intro

Definition □ Heart Failure- Clinical syndrome that can result from any structural or functional cardiac disorder that impairs ability of ventricle to fill with or eject blood. □ It occurs when the heart cannot deliver adequate cardiac output to meet the metabolic needs of the body.

9 Causes of HF with reduced LVEF □ Coronary artery disease

• Myocardial infarction
• Myocardial ischemia □ Chronic pressure overload
• Hypertension
• Obstructive valvular disease □ Chronic volume overload
• Regurgitant valvular disease
• Intracardiac (left- to- right) shunting
• Extracardiac shunting □ Non-ischemic dilated cardiomyopathy
• Familial/genetic disorder □ Toxic/drug-induced damage
• Alcohol/chemotherapy/smoking
• Viral
• Chagas' disease □ Disorders of rate and rhythm
• Chronic bradyarrhythmia
• Chronic tachyarrhythmias □ Diabetes type 2 □ Congenital heart disease □ Obesity □ Kidney dx

Causes of HF with

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preserved LVEF

□ Pathological

hypertrophy

• Primary (hypertrophic cardiomyopathies)
• Secondary (hypertension)

□ Aging

□ Myocardial ischemia

or infarction

□ Restrictive

cardiomyopathy

• Infiltrative disorders (amyloidosis, sarcoidosis)
• Storage diseases (hemochromatosis)

□ Fibrosis

□ Endomyocardial

disorders

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Risk factors of HF

Cigarette smoking

Alcohol use

Hypertension

Obesity

Diabetes

Coronary heart disease

Valvular heart disease

Kidney disease

13 Other classifications of HF & causes □ High output HF

• Chronic anemia
• Metabolic disorder; thyrotoxicosis, □ 'biventricular' or 'congestive' heart failure
• RV failure resulting from LV failure □ 'compensated‘ HF
• symptoms are stable and overt features of fluid retention are absent □ 'decompensated‘ HF
• refers to an acute or continuing deterioration □ Acute HF
• AMI, cardiogenic shock, ventricular septum rupture, pulmonary embolus □ Chronic HF
• Chronic failure with acute exacerbations

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Compensatory mechanisms

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in HF

1. Activation of the neurohormonal systems Involve activation of RAAS and adrenergic nervous system. Results in: - Increased salt and water retention thus high preload and Increase in preload increases force of contraction - Vasoconstriction, tachycardia and increase contractility

18 Compensatory mechanisms in HF 2.Ventricular hypertrophy and remodelling □ Hypertrophy refers to increased muscle mass □ Remodelling refers to ↑ mass and ↑ apoptosis of cardiomyocytes and ↑ collagen in extracellular matrix resulting in changes in size, shape, structure and function of the heart. □ Factors responsible for Ventricular Remodelling:

19 …Ventricular hypertrophy and remodelling □ Pressure overload e.g. in HTN leads to concentric hypertrophy i.e. ↑ ventricular thickness without chamber enlargement. This is characteristic of diastolic dysfunction □ Eccentric hypertrophy (myocyte lengthening) and chamber size (dilatation) with no change in wall thickness. This is characteristic of systolic dysfunction.