About a mechanical aid to the heart

About a mechanical aid to the heart

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I saw a news story a few years ago (I think) about a girl with a poor heart having a device implant that took over only some of the functioning of her heart ( I think they called it a piggy-back device , or something like that). The extraordinary thing is that it not only helped her live but all the heart functions started to improve. It was as if giving part of the heart a chance to 'rest' allowed the whole heart to improve. If this procedure works could it be applied to other organs? Could a Piggy-Back device be made for the liver taking over only some of its functions for instance? Could such a thing help the liver functions to 'regenerate'?

The function of heart is just to pump blood and nothing else. Though, it is a vital organ, its functions are limited. The device that you are talking about is a battery powered mechanical pump that performs the same function as heart.

Liver, however has a more complex function. One of its function is to synthesize and secrete certain molecules. A small artificial device cannot do that (you would need a bioreactor !!!).

We still haven't developed and artificial cell. Perhaps a consortium of bacteria can do some of the liver's functions but to culture them in right proportions and implant them without the risk of infection or their elimination is almost impossible as of now. You can clearly see that there are too many steps to be optimized.

Heart Failure and the LVAD

A left ventricular assist device, or LVAD, is a mechanical pump that is implanted inside a person's chest to help a weakened heart pump blood.

Unlike a total artificial heart, the LVAD doesn't replace the heart. It just helps it do its job. This can mean the difference between life and death for a person whose heart needs a rest after open-heart surgery or for people waiting for a heart transplant. LVADs are often called a "bridge to transplant."

LVADs may also be used as ''destination therapy.'' This means it is used long-term in some terminally ill people whose condition makes it impossible for them to get a heart transplant.

Heart Science Lesson

Cardiac Science

Did you know that your heart is made up of muscles? Not just any muscles, though! The muscles that keep your heart pumping are called cardiac muscles. They are particularly strong and can work constantly without becoming tired or sore the way other muscles often do.

Cardiac muscles are involuntary muscles, which means that they work whether you think about it or not. Think about the muscles in your arm. If you want to pick something up, you have to use your muscles to move your arm. Those muscles are voluntary muscles because you can control them.

The muscles that keep your heart pumping are involuntary because you cannot control them. It's a good thing, because if you forgot to tell your cardiac muscles to pump blood, even for a moment, it would cause a lot of problems for the rest of your body!

Human hearts have four chambers and work as a pump constantly delivering blood to the body.

Deoxygenated blood&mdashwhich needs a fresh supply of oxygen&mdashis brought by veins in from the body into the first chamber, known as the right atrium. The heart then pumps the blood through the first valve and into the right ventricle. Then it is pumped through the next valve and off to the lungs through a large artery.

In the lungs, the blood receives oxygen. From the lungs, the oxygenated blood is brought back to the heart. The blood passes through the left atrium through another valve and into the left ventricle from there it is pumped through yet another valve into arteries to be taken to the rest of the body.

This process of pumping blood through the body is called circulation and it repeats itself all day, every day throughout your life! Valves act like doors in your heart, controlling how much blood goes in and out. The "lub dub" beating sound your heart makes comes mostly from the valves opening and closing.

Can you think of any other examples of a pump? How about the pump on a soap bottle? A pump like that also has a valve inside that allows the soap to come out of the tip rather than sliding back down the tube.

How about other kinds of valves? A faucet has a valve that can close off to control how much or how little water comes out. When you turn the faucet's knobs, you control the valve. A sports drink bottle also has a valve that allows water out, but you can't pour water back in through it.

The Human Heart

Human hearts have four chambers and work as a pump delivering blood to your body.

Deoxygenated blood&mdashwhich needs a fresh supply of oxygen&mdashis brought by veins in from the body into the first chamber, known as the right atrium. The heart them pumps the blood into the right ventricle, and from there it is pumped to the lungs. In the lungs, the blood receives oxygen.

From the lungs, the oxygenated blood is brought back to the heart. The blood passes through the left atrium into the left ventricle, and from there it is pumped through your arteries to the rest of the body. Check out our heart worksheet to test your knowledge of the five basic parts of the heart.

The largest artery in the body is the aorta and it's located above the left ventricle. This process of moving blood through the body is called circulation and it repeats itself all day, every day throughout your life!

When you were exercising, you needed more oxygenated blood, so your heart had to work harder! That's why it beat faster after exercise. The sound of your heartbeat is the sound of valves in your heart closing. Valves act like doors in your heart, controlling how much blood goes in and out.

Blood's circulation path: body >> veins > > right atrium > > right ventricle >> lungs >> left atrium >> left ventricle >> arteries >> body

Heart Valves

The heart has four valves - one for each chamber of the heart. The valves keep blood moving through the heart in the right direction.

The mitral valve and tricuspid valve are located between the atria (upper heart chambers) and the ventricles (lower heart chambers).

The aortic valve and pulmonic valve are located between the ventricles and the major blood vessels leaving the heart.

Mitral Valve

The valves are made of strong, thin flaps of tissue called leaflets or cusps.

The leaflets open to let blood move forward through the heart during half of the heartbeat. They close to keep blood from flowing backward during the other half of the heartbeat.

The mitral valve has only two leaflets the aortic, pulmonic and tricuspid valves have three. The leaflets are attached to and supported by a ring of tough, fibrous tissue called the annulus. The annulus helps to maintain the proper shape of the valve.

The leaflets of the mitral and tricuspid valves are also supported by:

  • Chordae tendineae: tough, fibrous strings. These are similar to the strings supporting a parachute.
  • Papillary muscles: part of the inside walls of the ventricles.

The chordae tendineae and papillary muscles keep the leaflets stable to prevent blood from flowing backward.

Mitral Valve

Aortic Valve

How Valves Work

The four valves are to open and close to let blood flow through the heart. The steps below show how the blood flows through the heart and describes how each valve works to keep blood moving.

1. Open tricuspid and mitral valves
Blood flows from the right atrium into the right ventricle through the open tricuspid valve, and from the left atrium into the left ventricle through the open mitral valve.

2. Closed tricuspid and mitral valves
When the right ventricle is full, the tricuspid valve closes and keeps blood from flowing backward into the right atrium when the ventricle contracts (squeezes).
When the left ventricle is full, the mitral valve closes and keeps blood from flowing backward into the left atrium when the ventricle contracts.

3. Open pulmonic and aortic valve
As the right ventricle begins to contract, the pulmonic valve is forced open. Blood is pumped out of the right ventricle through the pulmonic valve into the pulmonary artery to the lungs.
As the left ventricle begins to contract, the aortic valve is forced open. Blood is pumped out of the left ventricle through the aortic valve into the aorta. The aorta branches into many arteries and provides blood to the body.

4. Closed pulmonic and aortic valves
When the right ventricle finishes contracting and starts to relax, the pulmonic valve snaps shut. This keeps blood from flowing back into the right ventricle.
When the left ventricle finishes contracting and begins to relax, the aortic valve snaps shut. This keeps blood from flowing back into the left ventricle.

This pattern is repeated, causing blood to flow continuously to the heart, lungs, and body. The four normally working heart valves make sure blood always flows freely in one direction and that there is no backward leakage.

Ventricular Assist Device

These devices can support the function of the left, right, or both heart ventricles. Ventricles are the lower chambers of your heart. The VAD includes tubes to carry blood out of your heart and to your blood vessels, a power source, and a control unit to monitor device function. The device may be used to support your heart until it recovers, to support your heart while you are waiting for a heart transplant, or to help your heart work better if you are not eligible for a heart transplant.

Surgery is required to connect the VAD to your heart. The surgery will be performed in a hospital. You will have general anesthesia and will not be awake or feel pain during the surgery. You will receive anticlotting medicine through an intravenous (IV) line in your arm. A breathing tube connected to a ventilator will help you breathe. A surgeon will open your chest and connect your heart’s arteries and veins to a heart-lung bypass machine. Your surgeon will place the pump in the upper part of your belly wall and connect the pump to your heart with a tube. Another tube will connect the pump to one of your major arteries. The VAD will be connected to the control unit and power source outside your body. When the heart-lung machine is switched off, the VAD will support blood flow and take over your heart’s pumping function.

After your surgery, you will recover in the intensive care unit (ICU) and may stay in the hospital for two to eight weeks. Hospital staff will help you to increase your activity gradually to gain strength. You may start a cardiac rehabilitation program. Your medical team will watch closely for signs of infection. To prevent infection, it is important to practice good hygiene, obtain routine vaccines, and properly clean and care for your device and the hole in your abdomen. You will be given instructions on what to do if the device gives a warning that it is not working correctly. If you are on the waiting list for a heart transplant, you will stay in close contact with the transplant center.

Getting a VAD involves serious risks such as blood clots and bleeding from the surgery or caused by the anticlotting medicines. Other risks include infection, device malfunction, and right-sided heart failure if a left VAD was used. Because blood tends to clot more when coming in contact with the VAD, you likely will need to take anticlotting medicines for as long as you have the device. It is important to take your medicines exactly as your doctor prescribes to prevent clots.

Visit Ventricular assist device for more information about this topic.

Advantages Of Mechanical Heart Valves

The main advantage of mechanical heart valve replacements is durability.

Mechanical heart valves are made from very durable materials including titanium, carbon compounds and teflon. While the average tissue valve (porcine, bovine, equine) is estimated to last between 10-15 years, reports suggest that mechanical valves can last 30 years or more after implant.

That said, for some younger patients, a mechanical heart valve can be a suitable replacement for the diseased valve.

Heart-lung machine

The heart-lung machine is a mechanical pump that maintains a patient’s blood circulation and oxygenation during heart surgery by diverting blood from the venous system, directing it through tubing into an artificial lung (oxygenator), and returning it to the body. The oxygenator removes carbon dioxide and adds oxygen to the blood that is pumped into the arterial system. The blood pumped back into the patient’s arteries is sufficient to maintain life at even the most distant parts of the body as well as in those organs with the greatest requirements (e.g., brain, kidneys, and liver). To do this, up to 5 litres (1.3 gallons) or more of blood must be pumped each minute. While the heart is relieved of its pumping duties, it can be stopped, and the surgeon can perform open-heart surgery that may include valve repair or replacement, repair of defects inside the heart, or revascularization of blocked arteries.

The first successful clinical use of a heart-lung machine was reported by American surgeon John H. Gibbon, Jr., in 1953. During this operation for the surgical closure of an atrial septal defect, cardiopulmonary bypass was achieved by a machine equipped with an oxygenator developed by Gibbon and a roller pump developed in 1932 by American surgeon Michael E. DeBakey. Since then, heart-lung machines have been greatly improved with smaller and more-efficient oxygenators, allowing them to be used not only in adults but also in children and even newborn infants.

Health Solutions From Our Sponsors

American Heart Association. "How to help prevent heart disease at any age." Apr 01, 2015.

Electrical System of the Heart. 2020.

Top Heart: How the Heart Works Related Articles

Atrial Fibrillation (AFib)

Coronary Heart Disease Screening Tests (CAD)

Coronary heart disease or coronary heart disease (CAD) screening tests can be used to potentially prevent a heart attack or cardiac event in a person without heart disease symptoms, and can assist in diagnosing heart disease in individuals with heart disease symptoms. Examples of coronary heart disease tests include:

  • electrocardiogram (ECC, EKG),
  • exercise stress test,
  • radionuclide stress test,
  • stress echocardiography,
  • pharmacologic stress test,
  • CT coronary angiogram, and
  • coronary angiogram.

High Blood Pressure (Hypertension)

High blood pressure (hypertension) is a disease in which pressure within the arteries of the body is elevated. About 75 million people in the US have hypertension (1 in 3 adults), and only half of them are able to manage it. Many people do not know that they have high blood pressure because it often has no has no warning signs or symptoms.

Systolic and diastolic are the two readings in which blood pressure is measured. The American College of Cardiology released new guidelines for high blood pressure in 2017. The guidelines now state that blood normal blood pressure is 120/80 mmHg. If either one of those numbers is higher, you have high blood pressure.

The American Academy of Cardiology defines high blood pressure slightly differently. The AAC considers 130/80 mm Hg. or greater (either number) stage 1 hypertension. Stage 2 hypertension is considered 140/90 mm Hg. or greater.

If you have high blood pressure you are at risk of developing life threatening diseases like stroke and heart attack.

REFERENCE: CDC. High Blood Pressure. Updated: Nov 13, 2017.

Homocysteine (Normal and Elevated Levels Blood Test)

Elevated homocysteine levels in the blood called hyperhomocysteinemia, is a sign that the body isn't producing enough of the amino acid homocysteine. is a rare and serious condition that may be inherited (genetic). People with homocystinuria die at an early age. Symptoms of hyperhomocysteinemia include developmental delays, osteoporosis, blood clots, heart attack, heart disease, stroke, and visual abnormalities.

There are other causes of hyperhomocysteinemia, for example, alcoholism.

Supplementing the diet with folic acid and possibly vitamins B6 and B12 supplements can lower homocysteine levels. Currently there is no direct proof that taking folic acid and B vitamins lower homocysteine levels and prevent heart attacks and strokes. Talk to your doctor if you feel you need to have your homocysteine blood levels checked.

Science of the Heart New!

New research shows the human heart is much more than an efficient pump that sustains life. Our research suggests the heart also is an access point to a source of wisdom and intelligence that we can call upon to live our lives with more balance, greater creativity and enhanced intuitive capacities. All of these are important for increasing personal effectiveness, improving health and relationships and achieving greater fulfillment.

This overview will explore intriguing aspects of the science of the heart, much of which is still relatively not well known outside the fields of psychophysiology and neurocardiology. We will highlight research that bridges the science of the heart and the highly practical, research-based skill set known as the HeartMath System.

The heart has been considered the source of emotion, courage and wisdom for centuries. For more than 30 years, the HeartMath Institute Research Center has explored the physiological mechanisms by which the heart and brain communicate and how the activity of the heart influences our perceptions, emotions, intuition and health. Early on in our research we asked, among other questions, why people experience the feeling or sensation of love and other regenerative emotions as well as heartache in the physical area of the heart. In the early 1990s, we were among the first to conduct research that not only looked at how stressful emotions affect the activity in the autonomic nervous system (ANS) and the hormonal and immune systems, but also at the effects of emotions such as appreciation, compassion and care. Over the years, we have conducted many studies that have utilized many different physiological measures such as EEG (brain waves), SCL (skin conductance), ECG (heart), BP (blood pressure) and hormone levels, etc. Consistently, however, it was heart rate variability, or heart rhythms that stood out as the most dynamic and reflective indicator of one&rsquos emotional states and, therefore, current stress and cognitive processes. It became clear that stressful or depleting emotions such as frustration and overwhelm lead to increased disorder in the higher-level brain centers and autonomic nervous system and which are reflected in the heart rhythms and adversely affects the functioning of virtually all bodily systems. This eventually led to a much deeper understanding of the neural and other communication pathways between the heart and brain. We also observed that the heart acted as though it had a mind of its own and could significantly influence the way we perceive and respond in our daily interactions. In essence, it appeared that the heart could affect our awareness, perceptions and intelligence. Numerous studies have since shown that heart coherence is an optimal physiological state associated with increased cognitive function, self-regulatory capacity, emotional stability and resilience.

We now have a much deeper scientific understanding of many of our original questions that explains how and why heart activity affects mental clarity, creativity, emotional balance, intuition and personal effectiveness. Our and others&rsquo research indicates the heart is far more than a simple pump. The heart is, in fact, a highly complex information-processing center with its own functional brain, commonly called the heart brain, that communicates with and influences the cranial brain via the nervous system, hormonal system and other pathways. These influences affect brain function and most of the body&rsquos major organs and play an important role in mental and emotional experience and the quality of our lives.

In recent years, we have conducted a number of research studies that have explored topics such as the electrophysiology of intuition and the degree to which the heart&rsquos magnetic field, which radiates outside the body, carries information that affects other people and even our pets, and links people together in surprising ways. We also launched the Global Coherence Initiative (GCI), which explores the interconnectivity of humanity with Earth&rsquos magnetic fields.

This overview discusses the main findings of our research and the fascinating and important role the heart plays in our personal coherence and the positive changes that occur in health, mental functions, perception, happiness and energy levels as people practice the HeartMath techniques. Practicing the techniques increases heart coherence and one&rsquos ability to self-regulate emotions from a more intuitive, intelligent and balanced inner reference. This also explains how coherence is reflected in our physiology and can be objectively measured.

The discussion then expands from physiological coherence to coherence in the context of families, workplaces and communities. Science of the Heart concludes with the perspective that being responsible for and increasing our personal coherence not only improves personal health and happiness, but also feeds into and influences a global field environment. It is postulated that as increasing numbers of people add coherent energy to the global field, it helps strengthen and stabilize mutually beneficial feedback loops between human beings and Earth&rsquos magnetic fields.

Power of a Human Heart

The human heart is a pump that is made of muscle tissue. It has four chambers: the right atrium and the left atrium, which are located at the top, and the right ventricle and left ventricle, which are located at the bottom. A special group of cells called the sinus node is located in the right atrium. The sinus node generates electrical stimuli that make the heart contract and pump out blood. Each contraction represents a heartbeat. When the heart contracts it is in a systolic phase and when it rests it is in a diastolic phase. It takes blood about a minute to circulate through the cardiovascular system and pump oxygenated blood throughout the body.

The power of the heart can be calculated by multiplying the pressure by the flow rate. An average person has six liters of blood that circulates every minute, making the flow rate 10 𕒸 m 3 /s (cubic meters per second). The pressure of the heart is about 10 4 pascal, making the heart's power about one watt. This is the power of a typical human heart, but it's different for everyone.

The average heart beats about 75 times per minute, which is about five liters of blood per minute. Although this isn't much, it enables the heart to complete a tremendous amount of work in a person's lifetime. The human heart beats about 40 million times a year, which adds up to more than 2.5 billion times in a 70-year lifetime. This results in approximately 2 to 3 billion joules of work in a lifetime, which is a huge amount.

Watch the video: Γιώργος Μεράντζας - Τύραννος (July 2022).


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