Types of Heart Valves

The heart valves that lie between the atria and ventricles are known as the atrioventricular (AV) valves. These valves are also known as cuspid valves because it has flaps or cusps that close together to form a seal when the ventricles are pumping. This prevents blood in the ventricle from flowing in the wrong direction, which is into the atria. The valves at the junction of the ventricles and great arteries are known as the semilunar valves due to the shape of the leaflets. It prevents blood that leaves the ventricle and enters the respective artery from flowing backwards when the ventricle relaxes.

What are the names of the four heart valves?

The heart valves are as follows :

• Atrioventricular Valves
  • Tricuspid valve lies between the right atrium and right ventricle. It has three flaps.
  • Bicuspid valve or mitral valve lies between the left atrium and left ventricle. It has two flaps.
• Semilunar Valves
  • Pulmonary valve or pulmonic valve lies between the right ventricle and pulmonary artery.
  • Aortic valve lies between the left ventricle and aorta.

How do the heart valves work?

All the heart valves work in the same way, which is to close when the blood is about to flow backwards. However, the process is a little more complex than this.

Atrioventricular Valves

The atrioventricular (AV) valves are made up of flaps that are attached via tendons known as chordae tendinae to small papillary muscles on the heart wall. It allows blood to pass from the atria into the ventricles. When the ventricle contracts the blood pushes the flaps of the AV valve together. However, the force of ventricular contraction may cause the valve to bend backwards but the papillary muscles contract thereby pulling on the chorda tendinae. This holds the flaps of the AV valves firm against the force of the blood pushing on it.

Semilunar Valves

The semilunar valves are like small cups that are flat against the vessel wall when blood is flowing in the right direction. This is during ventricular contraction when blood is expelled out of the heart and through the respective artery (pulmonary artery from the right ventricle, aorta from the left ventricle). However, at the end of ventricular contraction, the blood in the arteries begin to flow backward into the ventricle. This immediately fills the small cups of the respective semilunar valve which enlarges and closes. In this way, blood cannot enter the ventricle from the artery.

“You can easily get health benefits of 7 to 8 minute vigorous exercise in a week if you don’t find the time to perform regular exertion. However, it is against the established perspective of the physical exertion.” Dr. James A. Timmons said.

Researchers find out those inactive young men who do only 15 min intense exercise in two weeks, develop the ability to metabolize blood glucose more efficiently. Conventional aerobic exercises may also increase insulin sensitivity in the body. The heavy exercise did the same but also directly causes reduction in the men’s bloog sugar level, this is the edge of the heavy physical work out.

The approved guidelines for physical workout are 30 minutes a day persistently at least five days a week, but in this busy and hectic life, people are hardly finding any time to exercise. So the researchers present the hypothesis that high intensity physical work out may cause better insulin sensitivity and efficiency.

For the experiment, researchers’ selected 16 men aged 20 to 25 to perform six equivalent sessions of physical workout for less than half an hour, with 30 second quick sprinters then four minute rest period.

After the two weeks of activity, men’s blood sugar and insulin levels above optimal range after drinking a sugary solution of seventy-five grams.

“When we drink or eat something our blood sugar level get raised very quickly, in healthy and active persons it comes down quickly and in the sedentary person the time get prolonged to reach at normal level this long duration, over times, lead to diabetes and heart diseases.

The therapies mentioned in a recent study were published in Archives of Surgery journal.Therapies namely Full-thickness Plication and Radio Frequency Therapy include a procedure in which a long instrument; endoscope is inserted through mouth to reach the esophagus.

In full-thickness plication the endoscope is used. The in between junction of stomach and esophagus is tightened with sutures. Whereas in Radio Frequency therapy, heat is used to treat the function of in between valve of stomach and esophagus.

Both of these rare therapies have been found effective in reducing swallowing difficulties, voice hoarseness and heart burn. Heart burn is usually caused due to gastroesophageal reflux disease or GERD. In this disease the stomach acid is back fired towards the esophagus. This causes inflammation in esophagus lining.

Most of the patients are given Wyeth’s Protonix, Takeda Pharmaceutical Co’s Prevacid and Eisai Inc’s Aciphex, AstraZeneca Plc’s Nexium and Prilosec which do not trigger results in many. Such therapies are helpful especially for those who cannot afford surgery. As Dr. Edward Lin of Emory University School of Medicine in Atlanta said, “It’s nice to be able to offer something less invasive.”

Dr. Michael Miller, who authored the study, says: “Often listening to music makes you feel good as well as it’s a good preventive measure for your heart health. The good thing about it is that it doesn’t have any downside as it’s simple, economic and make your heart healthy”

Dr. Carl Lavie, who is medical director of cardiac rehabilitation and prevention director of the Stress Testing laboratory, says: “It’s a short-term study, but it suggests that laughter and listening to relaxing music can prove heart-healthy. However, the question is whether regular performance of this or similar activity has long-term benefits on the cardiovascular system.”

The study has been presented at the American Heart Association’s annual scientific sessions, in New Orleans. While presenting the study, Miller said: A lot of people look for heart health by avoiding negative risk factors that require to be overcome.”

There are also many other studies which suggest that music affect blood pressure and heart rate. Similarly, prayer also seems to improve cardiac performance. Previously, Miller and team have found that laughter improved vascular health.

In the first study, Japanese researchers noted that low-dose aspirin didn’t seem to lower the risk for cardiovascular events in patients with type2 diabetes.

The second study, conducted by Harvard researchers, showed that vitamin E or vitamin C didn’t seem to lower the risk of major cardiovascular events in a middle-aged male physicians’ group.

Diabetics have a much higher risk for cardiovascular events and the American Diabetes Association suggests the use of aspirin as a primary prevention measure. However, researchers from Kumamoto University, Japan say that there is little evidence to support the recommendation.

In the JPAD trial, 2539 Japanese patients with type2 diabetes were randomized. The patients had no history of atherosclerotic disease to low-dose aspirin or included in a non-aspirin control group.

Aspirin showed a slight reduction in the risk of coronary, peripheral vascular and cerebrovascular events in participants.

Some experts say that the study has left many questions unanswered.

According to Dr. Suzanne Steinbaum, director of women and heart disease at Lenox Hill Hospital in New York City, “We need to wait for more studies, and we don’t even know whether we can use this data to extrapolate to an American population.”

A report in the British Medical Journal says that the drug showed no benefit in those 1,300 adults who didn’t have any symptoms of heart disease.  It is worth mentioning that aspirin can cause stomach bleeds in some people.

The results are absolutely contrary to those many guidelines which support the view that diabetics should use aspirin to battle with the high risk of stroke and heart attack.

According to some experts, people who have been diagnosed with some heart disease aspirin seems to reduce almost 25% risk of recurring of the events like heart attack or stroke.

In the UK, there are almost more than 40million people with diabetes and around 80% diabetics die of heart attacks, strokes and other cardiovascular diseases.

Many UK guidelines suggest a daily dose of aspirin to prevent heart problems in diabetics.

However, the current study says that adults (over 40) with type 1 or type 2 diabetes and without any symptoms of heart disease were found without any difference over seven years when they were given aspirin or a dummy pill.

Professor Jill Belch, who led the study, says that aspirin is considered the commonest cause of hospital admission because of stomach bleeding.

According to this report that will be published in the September issue of the Clinical Journal of the American Society of Nephrology  demonstrates that dialysis are required to end-stage renal disease patients and they are not given heart-saving medicines like beta blockers and other cholesterol-lowering medicines.

“Kidney disease is considered an established risk factor for heart attack and other cardiovascular diseases and it also serves as an indicator for such events” stated Wolfgang C. Winkelmayer, of Brigham and Women’s Hospital, in Boston in a news release.

The data on medication use after a heart attack was analyzed by the researchers, the data related to almost 21,500 patients and most of them had kidney disease. The researchers adjusted other factors and found that patient with chronic kidney disease were 22 percent less apt to commence a beta blocker treatment. While patient with end-stage renal disease were 43 percent less likely to offer angiotensin-converting enzyme and other blockers.

Besides aspirin these three drugs are reckoned quite important to avoid cardiovascular issues that lead to heart attack.

The researchers stress on new ways to cut the risk of cardiovascular problems among kidney patients as the risks of kidney disease is getting bigger and bigger with every passing day.

Related links

•  Kidney Patients Less Likely to Get Heart Attack

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The miracle innovation was concluded by the scientists at the University of Minnesota. This research now has been published in the online issue of the “Nature Medicine” on January 13th.

“Whole Organ Decellularization (WOD) “process was adopted by the researchers, in which all the cells of a heart are removed, leaving only the ‘extracellular matrix’ or the ‘scaffolding’ between the cells. These cells actually form a physical framework.

Dr Doris Taylor, the lead researcher at the ‘University of Minnesota’ said,
“The idea would be to develop transplantable blood vessels or whole organs that are made from your own cells”.

Every year, millions of people across the world are diagnosed with heart failure. There is an acute shortage of donors worldwide. This situation causes millions of deaths every year. Until now, it was just a theoretical concept to provide a “Bioartificial” heart, or replacing part of a diseased heart with a working component grown in the lab to the patients. This discovery has turned the theory in to real practice now.

Prior to this development, scientists were able to generate only heart tissue in the laboratories. Creating a three-dimensional scaffold imitating the complex architecture had been almost a mystery, says Dr Doris Taylor.

Growing of ‘Bioartificial Heart’ in the laboratory involved three major steps including engineering the architecture of the organ, making and mimicking the cell composition, and activating the pumping action.

Researchers first “cleaned” the cells off the hearts of dead rats and pigs with detergents. It is ‘Decellularization’ by which they removed everything leaving only the ‘extracellular matrix’. This process facilitated the scientists with enough scaffolding parts including the blood vessels, valves, and heart chambers. With these organs they created a framework of the heart.

To mimic the heart cells, scientists then reseeded the framework with progenitor cardiac and endothelial cells from newborn rat hearts and put it in a sterile environment to grow. Eight numbers of such constructs were kept in a bioreactor for a period of 28 days. This process simulated heart physiology.

Four days later, some contractions were observed. After 8 days, scientists observed that the hearts were pumping using physiological load and electrical stimulation. Rate of this pumping was around 2 per cent of adult strength, or around 25 per cent of the strength of a 16 week fetus.

Researchers are very much optimistic about this discovery. They trust it will further help to increase availability of donor organs. Dr. Taylor explained that with this is the first step to showing it was possible to create a working heart in three dimensions. The next goal researchers say would be to “use a patient’s stem cells to build a new heart”.

“It opens a door to this notion that you can make any organ: kidney, liver, lung, pancreas, you name it and we hope we can make it,” said Dr.Taylor.

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CKD, as defined by a ‘Glomerular Filtration Rate (GFR)’ lower than 60 ml/min/1.73m2, is an independent risk factor for major CV events and death in diabetic patients, say Christian Schneider of the University of Cologne, Germany.

Christian Schneider and team at the University of Cologne ,analyzed data from the Prospective ‘Pioglitazone’ clinical trial in proactive macro-vascular events , which compared the effect of ‘Pioglitazone’ and ‘placebo’ in 5154 patients with Type 2 diabetes and macro-vascular disease.

Baseline analysis of the research findings show that out of the total 5154 patients nearly 597 participants, making a ratio of 11.6% , had ‘chronic kidney diseases’. These patients were older in age and had longer duration of diabetes with a higher prevalence of hypertension than those without chronic kidney diseases.

The study also pointed out that in comparison to those patients who did not have any chronic kidney diseases the patients with chronic kidney diseases were more likely to reach the primary composite end point of all related health problems. These could include mortality, myocardial infarction (MI), stroke, acute coronary syndrome, coronary and carotid arterial intervention, leg revascularization, or amputation above the ankle. The difference between the ratios of both the patients’ types was 27.5% to 19.6%.

Results obtained in the study do indicate similar trends on analysis in the way that the patients with chronic kidney diseases were also more likely to reach the secondary end point of all cause of mortality, MI, and stroke when compared to the patients with no chronic kidney diseases. In this case the difference existed with a ratio of 18.3% to the 11.5%.

Researchers observed that after treatment with ‘Pioglitazone’, only 23.7% and 14.6% of chronic kidney diseases patients met the primary and secondary end points, respectively. This is in comparison to the 30.7% and 21.4% of the patients who were treated with placebo.

It was observed by the researchers that the patients who were treated with ‘Pioglitazone’ showed considerable improvements in kidney functions. The results with these patients showed a reduction in estimated GFR of 0.8 ml/min/1.73m2/year, compared with the placebo group.

Christian Schneider and co-researchers concluded in their study report,”Patients who had CKD and were treated with pioglitazone were less likely to reach the composite end point of all-cause death, MI, and stroke, independent of the severity of renal impairment.”

These are the conclusive findings of a recent study carried out at the “University of Pitsbugh”.These findings were also presented recently at the annual meeting of the” Radiological Society of North America(RSNA)”.There have been several researches in recent past and there are enough evidences available that connect the cardiovascular health with the brain health.

Reliable estimations of the “National Heart, Lung and Blood Institute” reveal that there are almost 50 million Americans who are suffering from hypertension presently. All these people are open to direct risks of cardiac attacks and aneurysm. Mild cognitive impairment, which affects brain functions such as language, attention and reasoning, is a transition stage between normal aging deficits in the brain and greater levels of dementia.

This study demonstrates that good vascular health is equally good for the brain.“Even in people with Alzheimer’s disease, it is important to detect and aggressively treat hypertension and also to focus on disease prevention”, said Dr.Oscar Lopez, Professor of Neurology and Psychiatry at the University of Pittsburgh.

Researchers applied specific techniques and used ‘arterial spin-labeled magnetic resonance imaging (MRI)’. For 68 older adults, this technique was applied for measuring and imaging the blood flow in the brain.’ Arterial Spin-Labeled Magnetic Resonance Imaging (MRI)’ is a novel, non-invasive technique and it does not require any external contrast agent.

The study involved 48 normal individuals. This group of individuals included 38 with hypertension and 10 without; 20 Alzheimer’s patients, including 10 with hypertension and 10 without; and 20 adults with mild cognitive impairment, 10 with hypertension and 10 without.

The MRI results thus obtained showed that in all patient groups blood flow in the brain was substantially decreased in patients with hypertension compared to those individuals who did not have hypertension. Cerebral blood flow recorded came out to be the lowest among the Alzheimer’s patients with hypertension, but the normal group with hypertension showed significantly lower cerebral blood flow in comparison to the normal group having no hypertension.

The study results established that a positive change in the blood flow patterns will make impacts on the hypertension and would be helpful in contributing to the pathology of Alzheimer’s disease.

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