The human circulatory system is a two-part system, whose purpose is bringing blood rich in oxygen to the tissue and the body. When the heart contracts it pushes the blood out into two significant loops or cycle. In the systemic loop, the blood circulates into the blood system, bringing oxygen to all the organs, and tissues and collecting carbon dioxide waste. In the pulmonary circuit, the blood flows to and from the lungs, to release carbon dioxide and then pick up new oxygen. The systemic circuit is controlled by the left side of the heart, the pulmonary circuit is controlled by the right side of the heart.
The systemic cycle begins when the oxygen-rich blood coming from the lungs enters the upper left chamber of the heart, the left atrium. As the chamber fills it presses on the mitral valves and the blood flows down the left ventricle. When the ventricle contracts during the heartbeat the blood on the left side is forced into the aorta.
The blood leaving the aorta takes oxygen-rich blood to the rest of the body. The used blood returns to the heart through veins. All of the blood from the body is eventually collected into the large two veins, which is the superior vena cover which receives blood from the upper body and the inferior vena cover which receives blood from the lower body region. Both Venae cavae empty the blood into the right atrium.
From that point, the blood begins its journey in the pulmonary cycle, from the right atrium the blood travels into the right ventricle through the tricuspid valve. When the ventricles contract the blood is pushed into the pulmonary artery that divides into the two main parts one going to the left lung and the other going to the right lung. The fresh blood-filled lungs oxygen-filled blood returns to the left atrium of the heart through the pulmonary veins.
All the circulatory system is made up of two cycles they both occur at the same time. The contraction of the heart muscle begins in the two atria which then pushes the blood into the ventricle. Then the walls of the ventricles squeeze to force the blood into the Arteries, the arteries take the blood to the body and the pulmonary artery to the lungs. After this, the heart muscle relaxes to allow the blood flow from the veins to the fill atria. In healthy adults, the resting heart rate is 72 beat per minute but can change if a person is exerting themselves. Normal heart rate is usually between 60 to 100 bpm.
- Happens when the heart muscle cannot pump effectively enough to meet the bodies metabolic demands.
- The pump failure usually happens as a result of damage to the left ventricle, but may happen in the right ventricle as well. Usually left heart failure develops first.
- Heart failure also happens when there is not enough cardiac output caused by fluid build-up in the heart.
- It may also happen as result of damage to the heart muscle or impaired left or right ventricle.
Heart failure is characterised by objective evidence of underlying abnormality, the cardiac dysfunction that impairs the ability of the ventricle with or to eject. And weakened heart muscle.
Heart failure is classified as
- The high output or low
- Acute or chronic
- Left-sided or right-sided
- Forward or backwards
- Symptoms of heart failure may restrict the ability of a person to perform activities of daily living which then affects the quality of life
Factors that contribute to heart failure include arrhythmias, arrhythmias disrupt the normal atrial and ventricular filling synchrony. Bradycardia which reduces cardiac output. Pregnancy is another risk factor because it increases the overall cardiac output and infection which increase the metabolic demands and further burden the heart.
Another risk factor is anaemia, this is because it increases the cardiac output to the meet the oxygen demand. Finally increased physical activity, increased water or salt intake, emotional stress or failure to follow the prescribed treatment for the underlying heart issue.
Left-sided heart failure
There are two types of left side heart failure, we have heart failure with reduced ejection fraction which is also called systolic heart failure. This is where the left side of the heart loses it the ability to contract normally. The heart cannot pump with enough force to push blood into circulation.
Heart failure with preserved ejection fraction also called diastolic failure, this is where the left ventricle loses its ability to relax usually. The heart cannot adequately fill with blood during the resting period between each beat.
Right-sided heart failure
The right side of the blood pumps used blood that returns to the heart through the veins through the right atrium into the left ventricle. The right ventricle then pumps the blood out of the heart into the lungs for oxygenation. Right-sided heart failure usually happens when the left side of the heart fells.
When the left ventricle fails, the increased fluid pressure is transferred back through the lungs which ultimately damages the right side of the heart. When the right side of the heart fails, blood backs up in the veins, this usually causes swelling or congestion in the legs, ankles and swelling within the abdomen such as the Gi tract, liver causing ascites.
In Congestive heart failure as blood flow of the heart slows, blood returning to the heart through the veins backup which causes congestion in the body tissues. Most often there is swelling in the legs and ankles but can happen in other parts of the body as well.
Sometimes the fluid collects in the lungs and interferes with breathing causing shortness of breath, especially when an individual is laying down. This is called pulmonary oedema and if untreated can cause respiratory distress.
Heart failure can affect the kidney’s ability to dispense off sodium and water. And where ever sodium goes water follows, as a result of sodium and water retention swelling increases in the tissues as well. Another indicator of congestive heart failure is a raised Jugular venous pressure. JVP reflects the volume and pressure of the veins.
Stages of Congestive Heart failure
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Bristow, M. R., Saxon, L. A., Boehmer, J., Krueger, S., Kass, D. A., De Marco, T., … & DeVries, D. W. (2004). Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. New England Journal of Medicine, 350(21), 2140-2150.