Tuesday, December 30, 2008

Is Resetting Clock Linked to Heart Attack Risk?

Every year, some 1.5 billion people around the world are subjected to the seasonal clock changes. But, are you aware that the act of adjusting clock has something to do with the heart attack risk?

Researchers from Karolinska Institute in Stockholm reported in the New England Journal of Medicine that because of sleep deprivation, there is a 5-percent increase in heart attacks in the week after clocks are reset for summertime.

In the spring, the risk of suffering a heart attack has been increased significantly in the week after clocks are set forward, while in the autumn, the risk of getting a heart attack has been reduced by 5 percent on average when clocks are set back an hour. In Europe, the clocks are set forward on the last Sunday of March and the clocks are set back an hour on the last Sunday in October.

Basing on the data from a comprehensive register of all heart attacks in Sweden between 1987 and 2006, the so-called “Karolinska Study” found that the changes in heart attack rates are closely related to the effect of sudden time change upon the sleeping patterns and biological rhythms. As such, the sleep quality and sleep duration is affected for those who are unable to adjust to the changes. In fact, growing body of evidence has shown that disruption of the biological rhythms and sleep problems could increase the risk of cardiovascular disease.

The shift in the spring disrupts the biological rhythm and sacrifices an hour of potential sleep, but the autumn shift will actually cause a disruption of the chronobiological rhythm and a possibility for some extra sleep. In other words, there are 2 different mechanisms working against each other for the autumn shift.

According to researchers, Monday has been considered as the most dangerous day of the week for getting heart attack. In fact, some previous studies have attributed such phenomenon to the sudden increase in activity and stress for the week ahead.

Meanwhile, the Karolinska study also explained why people suffer sleep deprivation when clock is reset: People usually get up later and go later to bed during the weekend, so if one goes to bed later on Sunday but still need to get up early on Monday, he or she will end up with a sleep deprivation.

Sunday, December 28, 2008

Can Chemicals Used in Plastic Containers Also Lead to Heart Disease?

In 2003, more than 2 million metric tons of bisphenol A (BPA) were produced worldwide. Since then, the demand for this compound has increased by between 6 and 10 percent yearly. BPA is a chemical commonly used in baby bottles and plastic food containers.

A report published in the September 17 issue of the Journal of the American Medical Association (JAMA) linked BPA to diabetes, heart disease and liver abnormalities in adults. 1,455 adults were involved in the study.

According to the researchers, adults with the highest concentrations of BPA in their urine had nearly tripled the chances of cardiovascular disease, as compared to those with the least amounts of BPA in their systems. Meanwhile, they also found that adults with the highest BPA levels also had more than double the odds of getting diabetes.

In other words, higher urinary concentrations of BPA were shown to be associated with increased probabilities of developing cardiovascular disease, diabetes, and liver-enzyme abnormalities.

BPA is found in detectable levels in more than 90 percent of Americans not only through food but also through drinking water, dermal exposure, dental sealants and inhalation of household dusts.

In fact, a report published earlier during September 2008 by a group of toxicologists at the National Institute of Health (NIH) also revealed that the chemical found in many food containers, plastic bottles and dental fillings could have dangerous effects on the development of the brain and prostate gland fetuses and newborn babies. It is believed that BPA would interfere with estrogen, which is the hormone that plays a key role in fetal and childhood development.

Nevertheless, in a hearing on September 16, 2008 in Washington into the safety of BPA, Food and Drug Administration (FDA) insisted that BPA is safe because at the current levels of exposure, a margin of safety does exist, which is sufficient to protect consumers including adults and children.

Likewise, the industry group American Chemistry Council also maintains that BPA should not cause any health hazard at the levels currently contained in some consumer products, which is also in line with the conclusion of governments worldwide. They feel that more follow up studies are necessary to support a conclusion that BPA would cause any disease.

Thursday, December 25, 2008

Is It Possible for a Teenager to live without a Heart for nearly 4 Months?

An American teenager of age 14 managed to survive for 118 days without a heart. She suffered from dilated cardiomyopathy, which is a condition that the patient's heart becomes weakened and enlarged and could not pump blood efficiently. This type of heart disease would require her to undertake a heart transplant for her survival.

On November 19, 2008, doctors in Miami announced that the young patient was kept alive by a custom-made artificial blood-pumping device, and they believe that this was the first time a child had survived in this manner for such a long period. In fact, an adult patient in Germany had been kept alive for 9 months without a heart.

At a news conference at the University of Miami/Jackson Memorial Medical Centre, the young girl seemed very weak and admitted that the experience was very scary. She just felt that she was like a fake person who did not really exist. Meanwhile, she was so afraid that the device might just malfunction at any moment.

Earlier on July 2, she had a heart transplant at Miami’s Holtz Children’s Hospital but the new heart failed to work properly and the doctors had to remove it quickly. Then, the doctors had to implant 2 heart pumps, made by Thoratec Corp of Pleasanton, California, to keep her blood flowing while she was fighting a host of ailments and recovering her strength. After almost 4 months, she had another heart transplant on October 29. Though she remained hospitalized, she was mobile during the period of 118 days, to be exact.

The young patient also suffered renal failure and a kidney transplant was carried out the day after the second heart transplant. Though her prognosis was good, there is a 50 percent chance that a heart transplant patient will require a new heart some 12 or 13 years after the first surgery.

Monday, December 22, 2008

Is High Resting Heart Rate Linked to Diabetes and Obesity?

Heart rate is the number of heartbeats per minute. It can be determined by taking the pulse. Resting heart rate is a person’s heart rate at rest. It varies with age, size, sex, and overall cardiovascular condition. The best time to get one’s resting heart rate is in the morning before getting out of bed.

It is the sympathetic nervous system (SNS), which is a network of neurons in the body operating without conscious thought that regulates the heart rate. It is believed that the large intestine, blood vessels, pupil dilation, perspiration and blood pressure are affected by heart rate.

A recent report, published in the American Journal of Hypertension in December 2008, revealed that high resting heart rates might be linked to the development of diabetes and obesity. Researchers in Japan found that people with resting heart rates of over 80 beats per minute had a higher chance of developing insulin resistance, diabetes and cardiovascular disease.

As one of the first few studies to examine the impact of heart rates on human body’s metabolism, the project involved 614 participants who were followed over a period of 20 years. These participants were divided into 4 groups: people with heart rates of below 60, 60-69, 70-79, and over 80.

In comparison with people with heart rates below 60, those having heart rates of above 80 were 1.34 times more likely to be obese, 1.2 times more likely to develop insulin resistance, and 4.39 times more likely to end up diabetic.

Such findings help depict the link between obesity and the SNS, which might in turn also help understand their casual role in the development of heart attack and stroke, two of the leading causes of death worldwide.

The researchers believe that the excessive nerve activities may be the cause that a person becomes obese since they reduce the amount of fat burnt in the body.

Friday, December 19, 2008

A New Generation of Artificial Heart Will Avail by 2011!

Shortage of transplant donors for heart is a worldwide phenomenon. It is estimated to be a worldwide shortage of 20,000 heart donors every year. As such, several research teams from United States, Japan, South Korea, and Europe are expediting their pace for the development of a total artificial organ, which can permanently replace the human heart.

After spending 15 years to develop a total artificial organ, a European research team revealed that a fully implantable artificial heart has been developed and they are now moving from pure research to clinical application. Such prosthetic heart is ready to be manufactured and should be ready for human use by 2011.

The artificial organ has a shape like a real heart and has the same blood flow rhythm. The prototype uses the same technology as prosthetic heart valves that have already been used around the world, and is developed by Mr Carpentier, a leading heart transplant specialist.

The existing artificial hearts have the problem of rejection by the patient’s immune system or blood clotting. In order to solve such problem, the new artificial organ is made from chemically treated animal tissues.

It is meant for heart disease patients who have a massive heart attack or with late-stage heart failure, and for those who cannot be treated by drug therapy, ventricular assistance, have heart transplant failed, or heart transplant is not available.

So far, the artificial heart has been tested using digital simulation and on animals. The trials have indicated no complications.

The existing artificial heart is a thumb-sized device implanted in the patient’s chest that sucks blood from the heart and pumps it into the aorta. The device has to be recharged every 4 hours using an external battery. In United States and Europe, heart surgeons have implanted such ventricular assistance devices (VAD) in 220 patients since 2000.

Tuesday, December 16, 2008

Not More Than 2 Drinks for Women to Avoid Irregular Heartbeat!

Previous studies indicated that the consumption of a moderate amount of wine or other alcoholic drinks might help prevent heart disease.

In fact, a paper published on March 7, 2008 in the “American Journal of Medicine” indicated that people who commenced their drinking in middle age were 38 percent less likely to get a heart attack or other serious heart problem than abstainers were, even if they were overweight, had diabetes, hypertension (high blood pressure) or other heart risks.

Nevertheless, what is the optimal amount one should drink? Well, if you were a woman, consuming a drink or 2 will not put you at risk of getting irregular heartbeat, or what is also known as atrial fibrillation.

Several previous studies had already shown that medium to heavy drinking would lead to higher risk of atrial fibrillation among men. However, such link did not seem to establish among women, because not enough women were included in those studies.

A recent study, conducted by the researchers from Brigham and Women's Hospital and Harvard Medical School, reported that having more than 2 alcoholic drinks is associated with an increased risk of atrial fibrillation. The findings were published on Dec 3, 2008 in the Journal of the American Medical Association (JAMA).

Based on 34,715 women aged 45 and older and in good health at the start of the trial, the researchers found that alcohol consumption of up to 2 drinks per day would not lead to higher risk of incidental atrial fibrillation among these women. On the other hand, a small group of women who drank 2 or more alcoholic beverages per day had a risk of atrial fibrillation that was 1.6 times more than those non-drinking women.

In this study, questionnaires were used to assess alcohol consumption at the beginning of the trial and at follow-up checks. The irregular heartbeat was reported by individual woman via annual questionnaires and was confirmed later through a medical checkup.

However, the researchers indicated that careful interpretation should be carried out on their findings. This is because the number of women in some subgroups was rather small, and there is a possible threshold effect in the relationship between alcohol consumption and risk of atrial fibrillation among women.

Saturday, December 13, 2008

What Kind of Gene Could Prevent Heart Disease?

Heart failure, also known as congestive heart failure, is a condition in which the heart cannot supply adequate blood flow to the rest of the body's organs. Such condition is caused by significant or prolonged stress to the heart. It could simply occur following a heart attack, high blood pressure, certain infections, and because of genetic causes.

Statistics show that heart failure affects some 23 million people worldwide and kills about 600,000 every year.

Recently, a tiny piece of genetic material that plays a key role in heart failure has been identified by an international research team who also shows how an experimental compound prevents the condition in mice.

Using a treatment from Regulus Therapeutics, the scientists were able to block or silence the tiny strands of ribonucleic acid called microRNA. Regulus Therapeutics is a joint venture between US biotech companies Alnylam Pharmaceuticals Inc and Isis Pharmaceuticals Inc.

These genetic fragments are responsible for regulating the making of genes into proteins, and in this case, it was discovered that a failing heart had 3- to 5-times more of a particular microRNA called miR-21. The findings of the new study were reported on November 30, 2008 in the journal Nature.

To begin with, the researchers analyzed hundreds of microRNAs within human and mouse heart samples to identify miR-21 as a key cause of heart failure. Then, they gave some mice an experimental compound known as antagomir to block miR-21. In these mice, the heart failure was prevented while mice that did not get the drug developed heart failure. As compared with the mice that did not receive the treatment, mice with heart failure that later got the compound did improve.

In other words, cardiac disease could be prevented as well as cured because the results from the study showed that heart function and tissue damage improved in both cases.

This new study was viewed as a landmark event in the advancement of microRNA therapeutics as a new class of innovative medicines. Several big drug makers have already invested into RNA technology to search for promising biotech assets.

Earlier in November 2008, a United States team had also shown how a different bit of RNA known as microRNA-101 meant the difference between an easily treated tumors and an aggressive cancer.

Thursday, December 11, 2008

Toxin Gas Turns Out to be Remedy for Heart Failure!

Being a leading cause of hospitalization for the elderly, heart failure is a condition in which the heart muscle cannot pump enough blood to meet the body’s needs. This can be caused by previous injury to the heart muscle from a heart attack, diabetes, high blood pressure or obesity.

Hydrogen sulfide is colorless and highly toxic. It is a flammable gas that not only has rotten-egg smell, but also is potentially dangerous for miners and sewer workers.

In a recent study, researchers from Emory University School of Medicine, in Atlanta, Georgia found that small dose of hydrogen sulfide helps protect laboratory mice from heart failure through its ability to regulate blood pressure and reduce inflammation.

The findings, presented in November 2008 at the American Heart Association's annual conference meeting at New Orleans, Louisiana, revealed that hydrogen sulfide appears to stimulate heart muscle cells and produce their own antioxidants and molecules that stave off programmed cell death caused by loss of blood flow.

In order to create a model of cardiac failure, the researchers blocked the laboratory mice’s left coronary arteries either temporarily for an hour or permanently to cause part of their heart muscles to die. Then, some of the mice were treated with a solution of hydrogen sulfide administered intravenously once a day for a week, while others left untreated to become the control group.

After a period of 4 weeks, researchers tested both groups’ heart capacity through their ‘ejection fraction’, a measure of heart function. Mice treated with the toxic gas showed an ejection fraction of 33 percent higher than those mice in the control group (36 percent compared to 27 percent).

Such results indicated that hydrogen sulfide can actually blunt the impact of heart failure on heart function and mortality in a mouse model of heart failure, and it is hoped that such experimental treatment could benefit humans one day.

Tuesday, December 09, 2008

Sleep Adequately to Prevent Heart Disease!

If a person reduces his or her sleep duration, then his or her risk of getting heart disease would be higher.

A recent study indicated that sleeping less than 7.5 hours a night would increase the chance of cardiovascular risk, including heart attack and stroke, by 33 percent. The paper was published by researchers from Jichi Medical University on November 12, 2008 in the Journal of the American Medical Association's Archives of Internal Medicine.

The sleep of 1,255 people with hypertension (also known as high blood pressure) was monitored by the Japanese researchers for an average period of 50 months. Their daytime and nighttime blood pressure, sleep duration, and cardiovascular disease events like heart attack, stroke and sudden cardiac death were tracked.

In the study, there were 99 incidents of cardiovascular disease being recorded. It was also found that the rate for people who slept less than 7.5 hours was 2.4 per 100 person-years. Those who slept more had a lower incident rate of 1.8 per 100 person-years. Meanwhile, the researchers also discovered that people whose blood pressure rose at night were more prone to heart disease.

The researchers believed that shorter duration of sleep is actually a predictor of incident cardiovascular disease in elderly individuals with hypertension.

In the meantime, inadequate sleep has also been linked to higher chances of diabetes, obesity and several risk factors for cardiovascular disease, which includes nighttime hypertension and sleep-disordered breathing.

Sunday, December 07, 2008

Are You Having High Blood Pressure Without Knowing It?

High blood pressure is also known as hypertension. It has been found by previous research that people with high blood pressure will be at a higher risk of getting heart disease, kidney disease, stroke and dementia.

As defined by the World Health Organization (WHO), high blood pressure is defined as being 140 over 90 mm of mercury or more. Mercury is the fluid used in the blood pressure gauges. The first number (140 mm), known as systolic, measures maximum heart pressure while the second (90 mm), known as diastolic, measures pressure when heart is in a resting phase (diastolic).

Many people who already have hypertension are just not aware of the condition. In fact, a recent study by Warwick Medical School in Britain and other institutes in Europe reported that more than half of people in 3 European countries who were diagnosed with high blood pressure did not know they had the condition. In addition, half of those who were aware that they had hypertension had managed to have their problems under control.

The findings were published in the International Society of Hypertension's Journal of Hypertension on November 12, 2008.

1,604 persons from Southwest London, Limburg in Belgium and Abruzzo in Italy, who participated in the study, answered questions regarding healthcare and lifestyle habits.

24 percent of the participants were found to have high blood pressure, yet only 44 percent of them were aware of their condition. Among these people, less than half had reduced their blood pressure to below 140 over 80 mm of mercury, the widely accepted benchmark of health.

According to the researchers, management of hypertensive problem is considered better in Britain than in many other European countries, partly because doctors in Britain have incentives to help patients reach targeted blood pressure. However, the incidence of high blood pressure is still rising, as too many patients are still not adequately treated.

Thursday, December 04, 2008

No MP3 Headphone Near Heart Disease Patients Equipped with Defibrillator!

Listening to MP3 songs and music using MP3 digital music players with headphone has become a lifestyle of today’s youth. Lately, it seems to gain popularity among older generations as well. Nowadays, it is rather difficult to find a mobile phone that is without MP3 player.

From now on, people who like to listen to music using MP3 player with headphone should be more careful. This is because a new study revealed that the headphone used in MP3 player, if placed within an inch of lifesaving cardiac devices such as pacemakers or implantable defibrillators, the operation of those devices may be interfered.

Presented the findings at an American Heart Association conference during November 2008, the researchers from the Medical Device Safety Institute at Beth Israel Medical Center in Boston, Massachusetts found that neodymium appears to cause the devices to function improperly. This could thus pose a potential great risk to heart disease patients who rely on the devices. Neodymium is a magnetic substance that can be found in the MP3 player headphones.

By exposing to headphones, a defibrillator could temporarily be deactivated. As such, headphones accompanying the popular MP3 digital music players must be at a distance of at least 1.2 inches (or 3 centimeters) away from the implanted devices, according to the study.

Meanwhile, the scientists caution heart disease patients, who use heart devices, not to put the MP3 player headphones in their pocket or to hang them over their chest. They also advise friends or family members of heart disease patients with implantable defibrillators to avoid wearing headphones and not to rest their head right on top of the devices used in their family members or friends.

Nevertheless, the researchers determined that outside studies did not find any adverse reactions to pacemakers and defibrillators from other portable electronic devices like iPod, Bluetooth headsets, iPhone, electric blankets or hand-held airport metal detectors.

Incidentally, both iPod and iPhone are MP3 players and headphones used in other digital music players can be used in iPod and iPhone too. I wonder why there is such a different reaction. Perhaps further studies should be carried out to ascertain such disparities.

Tuesday, December 02, 2008

More Power Means More Functions For Pacemaker!

A pacemaker is a small device, which can be installed under the skin of a person’s chest or abdomen, for helping control abnormal heart rhythms. By using electrical pulses, such devices can prompt the heart to beat a normal rate.

Arrhythmia is the name given to describe abnormal heart rhythms. When a person has symptoms related to arrhythmias, his or her heart rhythms can be too slow, fast or simply irregular. With the help of a pacemaker, a person with abnormal heart rhythm could resume a more active lifestyle.

It has always been the wish of doctors to incorporate more functions into the pacemakers to help monitor the heart. However, to add new functions into pacemaker means more power is required, and the only way to increase the power is to use larger-size and heavier battery. Unfortunately, such change would certainly make patients feel uncomfortable and arouse rejection from the patients.

Good news has emerged recently when researchers have developed a tiny generator that can harvest the excess energy of a beating heart to help power a pacemaker or defibrillator, according to a paper presented at the American Heart Association's annual meeting during November 2008.

By capturing enough surplus heart energy, the experimental micro-generator, developed by the researchers from Southampton University Hospital in Britain, can in turn provide 17 percent of the power required to run a pacemaker. This means that new generation of devices that lasted significantly longer would be available soon and more functions that can help monitor the heart can be added.

Right now, the researchers have already started their work on how to improve the materials used in the generator in order to enhance the energy harvesting.