chapter 1 - heart failure

8/6/2019 Chapter 1 - Heart Failure

http://slidepdf.com/reader/full/chapter-1-heart-failure 1/17

Drugs affecting the Cardiovascular

SystemHeart Failure

Wesam R. Kadhum



The heart

� The heart is roughly the size of a clenched fistand weighs about 300g. It lies in the centre of

the chest, surrounded by a protectivemembrane called the pericardium.

� In an average day, the heart pumps theequivalent of nearly 22,750 litres (5,000gallons) of blood around the body.

� The heart is a muscular pump, divided intoleft and right sides, and its muscular wallssqueeze (contract), pumping blood into theblood vessels and around the body.

1. Introduction

Heart Physiology



� The right side of the heart

receives deoxygenatedblood though the veins.This blood is pumped backto the lungs where itabsorbs oxygen.

� This oxygenated bloodthen returns to the leftside of the heart, which

pumps it out to the rest of the body through thearteries.



� The muscle on the left side of the heart is

slightly larger because it has more work to do,

pumping blood around the body.

� Each side of the heart is divided into an upper

chamber called an atrium and a larger, lowerchamber, called a ventricle.

� Blood flows from each atrium to the ventricle

below, through a one-way valve.



II. Physiology of Muscle Contraction

� Cardiac muscle is a type of involuntary striated

muscle found in the walls and histologicfoundation of the heart, specifically themyocardium. Cardiac muscle is one of threemajor types of muscle, the others being skeletal

and smooth muscle.

� However, unlike skeletal muscle, which showsgraded contractions depending on the number of muscle cells that are stimulated, the cardiacmuscle cells are interconnected in groups thatrespond to stimuli as a unit, contracting togetherwhenever a single cell is stimulated.



� In biology, depolarization

is a change in a cell's

membrane potential,making it more positive,

or less negative.

�

Membrane potential isthe difference in voltage

(or electrical potential

difference) between the

interior and exterior of acell (V

interior V

exterior ).



A. Action potential

� Cardiac muscle cells are electrically excitable



� The cardiovascular system includes the heartand the blood vessels make up the networkthat delivers blood to the body's tissues. With

each heartbeat, blood is sent throughout ourbodies, carrying oxygen and nutrients to all of our cells.

� The main purpose is to maintain adequate

blood circulation and hence the distribution of nutrients to tissues and the delivery of metabolic wastes to excretory/urinary organs.

2. Cardiovascular system (CVS)



� How does your cardiovascular system work?

� You breathe air through your mouth and nose and it travels

to your lungs.� Oxygen from the air is absorbed into your bloodstream

through your lungs.

� Your heart then pumps oxygen-rich ('oxygenated') bloodthrough a network of blood vessels - the arteries - to

tissues including your organs, muscles and nerves, allaround your body.

� When blood reaches your tissues, through the capillaries, itreleases oxygen, which is used by cells to produce energy.In exchange, these cells release waste products, such as

carbon dioxide and water, which are absorbed and carriedaway by your blood.

� The used (or 'deoxygenated') blood then travels along yourveins and back towards your heart. Your heart pumps thedeoxygenated back to your lungs, where fresh oxygen isabsorbed, and the cycle starts once again



� Your cardiovascular health

� Your lifestyle plays an essential part inmaintaining your long-term cardiovascular

health. A healthy diet, moderate drinking,

plenty of exercise, and stopping smoking canall help to maintain a healthy cardiovascular

system.



3.Heart Failure (HF)

� Heart failure is a term used todescribe the condition when theheart becomes less efficient atpumping blood and is thereforeunable to meet the demands of thebody.

� It's important to remember thatheart failure only means that your

heart isn't working as well as itused to, not that it has failedcompletely.



Symptoms of heart failure

� Common symptoms of heart failure include

breathlessness, tiredness, and swollen feet

and ankles. Other symptoms depend on which

side of your heart is most affected.



� Left-sided heart failure affects the lungs and

ability to breathe. Symptoms include

breathlessness when exercising and/or when

lying flat, extreme tiredness, wheezing and a

cough with a pink froth, usually occurring at

night.

�

Right-sided heart failure affects the fluid balancein the body. Symptoms include swollen ankles,

feeling sick, extreme tiredness and weight gain



Diagnosis of heart failure

� Heart failure is diagnosed based upon yourmedical history, an exam, and a series of tests.

These tests can tell your doctor how well your

heart is working and can help determine thecause of your heart failure. Tests may include:

� blood and urine tests to check your blood

count, liver function and for markers of heart

failure.



� an ECG (electrocardiogram)

- a test that measures theelectrical activity of your

heart to see how well it's

working.

� an echocardiogram (heart

ultrasound scan) to show

the pumping action of your

heart and valves.

� a chest X-ray to rule out

other conditions.



Treatmen

tDrugs Classification

chapter 1 - heart failure

Documents