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Long QT Syndrome

Definition:
The long QT syndrome (LQTS) is a rare inborn heart condition in which delayed repolarization of the heart following a heartbeat increases the risk of episodes of torsade de pointes (TDP, a form of irregular heartbeat that originates from the ventricles). These episodes may lead to palpitations, fainting and sudden death due to ventricular fibrillation. Episodes may be provoked by various stimuli, depending on the subtype of the condition.
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You can be born with a genetic mutation that puts you at risk of long QT syndrome. In addition, certain medications and medical conditions may cause long QT syndrome.

The condition is so named because of the appearances of the electrocardiogram (ECG/EKG), on which there is prolongation of the QT interval.

Long QT syndrome is treatable. You may need to limit your physical activity, avoid medications known to cause prolonged Q-T intervals or take medications to prevent a chaotic heart rhythm. Some people with long QT syndrome need surgery or an implantable device.

Symptoms :
Many people with long QT syndrome don’t have any signs or symptoms. They may be aware of their condition only from results of an electrocardiogram (ECG) performed for an unrelated reason, because they have a family history of long QT syndrome or because of genetic testing results.

For people who do experience signs and symptoms of long QT syndrome, the most common symptoms include:

*Fainting. This is the most common sign of long QT syndrome. In people with long QT syndrome, fainting spells (syncope) are caused by the heart temporarily beating in an erratic way. These fainting spells may happen when you’re excited, angry or scared, or during exercise. Fainting in people with long QT syndrome can occur without warning, such as losing consciousness after being startled by a ringing telephone.

Signs and symptoms that you’re about to faint include lightheadedness, heart palpitations or irregular heartbeat, weakness and blurred vision. However, in long QT syndrome, such warning signs before fainting are unusual.

*Seizures. If the heart continues to beat erratically, the brain becomes increasingly deprived of oxygen. This can then cause generalized seizures.

*Sudden death. Normally, the heart returns to its normal rhythm. If this doesn’t happen spontaneously and paramedics don’t arrive in time to convert the rhythm back to normal with an external defibrillator, sudden death will occur.Signs and symptoms of inherited long QT syndrome may start during the first months of life, or as late as middle age. Most people who experience signs or symptoms from long QT syndrome have their first episode by the time they reach age 40.

Rarely, signs and symptoms of long QT syndrome may occur during sleep or arousal from sleep.

Causes:
Your heart beats about 100,000 times a day to circulate blood throughout your body. To pump blood, your heart’s chambers contract and relax. These actions are controlled by electrical impulses created in the sinus node, a group of cells in the upper right chamber of your heart. These impulses travel through your heart and cause it to beat.

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After each heartbeat, your heart’s electrical system recharges itself in preparation for the next heartbeat. This process is known as repolarization. In long QT syndrome, your heart muscle takes longer than normal to recharge between beats. This electrical disturbance, which often can be seen on an electrocardiogram (ECG), is called a prolonged Q-T interval.

Prolonged Q-T interval
An electrocardiogram (ECG, also called an EKG) measures electrical impulses as they travel through your heart. Patches with wires attached to your skin measure these impulses, which are displayed on a monitor or printed on paper as waves of electrical activity.

An ECG measures electrical impulses as five distinct waves. Doctors label these five waves using the letters P, Q, R, S and T. The waves labeled Q through T show electrical activity in your heart’s lower chambers.

The space between the start of the Q wave and the end of the T wave (Q-T interval) corresponds to the time it takes for your heart to contract and then refill with blood before beginning the next contraction.

By measuring the Q-T interval, doctors can tell whether it occurs in a normal amount of time. If it takes longer than normal, it’s called a prolonged Q-T interval. The upper limit of a normal Q-T interval takes into account age, sex, and regularity and speed of the heart rate.

Long QT syndrome results from abnormalities in the heart’s electrical recharging system. However, the heart’s structure is normal. Abnormalities in your heart’s electrical system may be inherited or acquired due to an underlying medical condition or a medication.

Inherited long QT syndrome
At least 12 genes associated with long QT syndrome have been discovered so far, and hundreds of mutations within these genes have been identified. Mutations in three of these genes account for about 70 to 75 percent of long QT syndrome, and cause the forms referred to as LQT1, LQT2 and LQT3.

Doctors have described two forms of inherited long QT syndrome:

*Romano-Ward syndrome. This more common form occurs in people who inherit only a single genetic variant from one of their parents.

*Jervell and Lange-Nielsen syndrome. Signs and symptoms of this rare form usually occur earlier and are more severe than in Romano-Ward syndrome. It’s seen in children who are born deaf and have long QT syndrome because they inherited genetic variants from each parent.

Additionally, scientists have been investigating a possible link between SIDS and long QT syndrome and have discovered that about 10 percent of babies with SIDS had a genetic defect or mutation for long QT syndrome.

Acquired long QT syndrome
More than 50 medications, many of them common, can lengthen the Q-T interval in otherwise healthy people and cause a form of acquired long QT syndrome known as drug-induced long QT syndrome.

Medications that can lengthen the Q-T interval and upset heart rhythm include certain antibiotics, antidepressants, antihistamines, diuretics, heart medications, cholesterol-lowering drugs, diabetes medications, as well as some antifungal and antipsychotic drugs.

People who develop drug-induced long QT syndrome may also have some subtle genetic defects in their hearts, making them more susceptible to disruptions in heart rhythm from taking drugs that can cause prolonged Q-T intervals.

Risk Factors:
People at risk of long QT syndrome include:

*Children, teenagers and young adults with unexplained fainting, unexplained near drownings or other accidents, unexplained seizures, or a history of cardiac arrest

*Family members of children, teenagers and young adults with unexplained fainting, unexplained near drownings or other accidents, unexplained seizures, or a history of cardiac arrest

*Blood relatives of people with known long QT syndrome

*People taking medications known to cause prolonged Q-T intervals

Long QT syndrome often goes undiagnosed or is misdiagnosed as a seizure disorder, such as epilepsy. However, researchers believe that long QT syndrome may be responsible for some otherwise unexplained deaths in children and young adults. For example, an unexplained drowning of a young person may be the first clue to inherited long QT syndrome in a family.

People with low potassium, magnesium or calcium blood levels — such as those with the eating disorder anorexia nervosa — may be susceptible to prolonged Q-T intervals. Potassium, magnesium and calcium are all important minerals for the health of your heart’s electrical system.

Diagnosis:
The diagnosis of LQTS is not easy since 2.5% of the healthy population have prolonged QT interval, and 10–15% of LQTS patients have a normal QT interval. A commonly used criterion to diagnose LQTS is the LQTS “diagnostic score”. The score is calculated by assigning different points to various criteria (listed below). With four or more points, the probability is high for LQTS; with one point or less, the probability is low. A score of two or three points indicates intermediate probability.

*QTc (Defined as QT interval / square root of RR interval)
#>= 480 msec – 3 points
#460-470 msec – 2 points
#450 msec and male gender – 1 point

*Torsades de pointes ventricular tachycardia – 2 points

*T wave alternans – 1 point

*Notched T wave in at least 3 leads – 1 point

*Low heart rate for age (children) – 0.5 points

*Syncope (one cannot receive points both for syncope and torsades de pointes)
#With stress – 2 points
#Without stress – 1 point

*Congenital deafness – 0.5 points

*Family history (the same family member cannot be counted for LQTS and sudden death)
#Other family members with definite LQTS – 1 point
#Sudden death in immediate family (members before the age 30) – 0.5 points
Treatment options:
Those diagnosed with long QT syndrome are usually advised to avoid drugs that would prolong the QT interval further or lower the threshold for TDP.  In addition to this, there are two intervention options for individuals with LQTS: arrhythmia prevention and arrhythmia termination.

Arrhythmia prevention:
Arrhythmia suppression involves the use of medications or surgical procedures that attack the underlying cause of the arrhythmias associated with LQTS. Since the cause of arrhythmias in LQTS is after depolarizations, and these after depolarizations are increased in states of adrenergic stimulation, steps can be taken to blunt adrenergic stimulation in these individuals. These include:

*Administration of beta receptor blocking agents which decreases the risk of stress induced arrhythmias. Beta blockers are the first choice in treating Long QT syndrome.
In 2004 it has been shown that genotype and QT interval duration are independent predictors of recurrence of life-threatening events during beta-blockers therapy. Specifically the presence of QTc >500ms and LQT2 and LQT3 genotype are associated with the highest incidence of recurrence. In these patients primary prevention with ICD (Implantable cardioverter-defibrillator) implantation can be considered.

*Potassium supplementation. If the potassium content in the blood rises, the action potential shortens and due to this reason it is believed that increasing potassium concentration could minimize the occurrence of arrhythmias. It should work best in LQT2 since the HERG channel is especially sensitive to potassium concentration, but the use is experimental and not evidence based.

*Mexiletine. A sodium channel blocker. In LQT3 the problem is that the sodium channel does not close properly. Mexiletine closes these channels and is believed to be usable when other therapies fail. It should be especially effective in LQT3 but there is no evidence based documentation.

*Amputation of the cervical sympathetic chain (left stellectomy). This may be used as an add-on therapy to beta blockers but modern therapy mostly favors ICD implantation if beta blocker therapy fails.

Arrhythmia termination:
Arrhythmia termination involves stopping a life-threatening arrhythmia once it has already occurred. One effective form of arrhythmia termination in individuals with LQTS is placement of an implantable cardioverter-defibrillator (ICD). Alternatively, external defibrillation can be used to restore sinus rhythm. ICDs are commonly used in patients with syncopes despite beta blocker therapy, and in patients who have experienced a cardiac arrest.

It is hoped that with better knowledge of the genetics underlying the long QT syndrome, more precise treatments will become available.
Prognosis:
The risk for untreated LQTS patients having events (syncopes or cardiac arrest) can be predicted from their genotype (LQT1-8), gender and corrected QT interval.

*High risk (>50%)
QTc>500 msec LQT1 & LQT2 & LQT3 (males)

*Intermediate risk (30-50%)
QTc>500 msec LQT3 (females)

QTc<500 msec LQT2 (females) & LQT3

*Low risk (<30%)
QTc<500 msec LQT1 & LQT2 (males)

Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose

Resources:
http://www.bbc.co.uk/health/physical_health/conditions/longqt1.shtml
http://www.mayoclinic.com/health/long-qt-syndrome/DS00434
http://en.wikipedia.org/wiki/Long_QT_syndrome
http://paramedicine101.blogspot.com/2009/09/long-qt-syndrome-part-iii.html
http://www.itriagehealth.com/disease/long-qt-syndrome-(qt-prolongation)

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Exercise Can be a Dose of Good Medicine

Fitness programs are beginning to augment traditional disease treatment

On a recent Wednesday night, Cindy Gerstner, 42, strapped her feet into a rowing machine and began gliding back and forth with all the energy she could muster. This wasn’t just a workout for Ms. Gerstner, whose stage IV breast cancer has spread to her brain, lungs, bones, and liver. It was a 40-minute dose of medicine.

“It’s part of my treatment plan,” said Ms. Gerstner, a member of Recovery on Water or ROW, a crew team made up of breast cancer patients and survivors who believe exercise is a powerful tool to help keep cancer at bay. “It’s almost as important as chemotherapy in helping me stay on this earth as long as possible.”

Once relegated to health clubs, exercise is muscling its way into a wide variety of disease prevention and treatment plans. Physical fitness programs are already a staple of cardiac care. But though research is still in the early stages, there’s encouraging evidence that consistent workouts can help with everything from cancer, autoimmune disorders, and Parkinson’s disease to alcoholism.

University of Illinois scientists recently received funding for a study that looks at whether riding a stationary bicycle during treatment can help dialysis patients.

The burgeoning “exercise is medicine” movement is championed by dozens of organizations, including the American College of Sports Medicine, the Chicago Park District, and cancer support groups. New national cancer guidelines urge both patients and survivors to exercise during and after treatment for 150 minutes per week, the same advice given to the general public.

Some big questions remain unanswered, such as what type and how much exercise is needed for what illnesses. In many cases, working out appears to relieve symptoms, but its impact on the natural course of the disease isn’t known. And many physicians are cautious about prescribing something that can stress the body, especially for patients in the throes of a life-threatening illness.

“There’s still a prevailing attitude out there that patients shouldn’t push themselves during treatment,” said Kathryn Schmitz, an associate professor of epidemiology and biostatistics at the Abramson Cancer Center at the University of Pennsylvania school of medicine and lead author of the new guidelines.

Ms. Schmitz acknowledges that exercise is a stressor on the body but said resting too much also can have adverse effects.

If exercise isn’t already a habit, of course, it can be intimidating. It’s harder to do when you don’t feel good. And “some people would truly rather take a pill,” said Holly Benjamin, an associate professor and pediatric sports medicine specialist at the University of Chicago.

“But once they do it, so many people feel so much better.”

In the past, breast cancer patients who had undergone surgery were told not to lift more than 15 pounds for the rest of their lives, fearing that strenuous effort would slow treatment or exacerbate conditions.

But Ms. Schmitz’s groundbreaking work, published last year in the New England Journal of Medicine, reversed decades of cautionary advice by finding that slow, progressive weight lifting wasn’t just safe; it could prevent lymphedema flare-ups.

Exercise can help people being treated for cancer cope with the side effects of chemotherapy, surgery, and radiation, including fatigue and the loss of muscle mass.

“It helps them get through treatment in better form,” said David Nieman, director of the Human Performance Labs at Appalachian State University and the author of several textbooks on exercise as medicine.

A handful of observational studies, meanwhile, have suggested that exercise could result in a 40 to 50 percent reduction in the risk for recurrence of breast cancer, said Ms. Schmitz, though randomized controlled trials would be needed to prove a benefit.

For a few conditions, including Parkinson’s disease, there’s hope that exercise can affect the illness itself. In animal studies, exercise improved symptoms and increased the level of brainderived neurotrophic factor, a chemical that protects cells.

“Exercise may modify disease by slowing the primary process of cell loss associated with Parkinson’s disease,” said Cynthia Comella, a neurologist at Rush University Medical Center, who is currently investigating the effects on Parkinson’s of regular exercise with a personal trainer.

For treatment of pediatric rheumatic diseases, “exercise has been overlooked,” said Bruno Gualano of the University of Sao Paulo in Brazil.

Traditionally, children with inflammatory diseases have been treated with drugs that can have side effects. But certain types of exercise can be safe and effective treatment for symptoms including muscle wasting, osteoporosis, insulin resistance, pain, and fatigue.

Exercise’s greatest strength may be that it can work on both physical and emotional levels.

If some health advocates had their way, exercise would be the most widely prescribed “drug” in the country.

In Chicago, for example, any resident with an exercise prescription from a doctor for an obesity-related disease — including diabetes, high blood pressure, and asthma — can receive a free three-month membership to Chicago Park District fitness centers.

And for the past several years, the Erie Family Health Center, which provides care in Chicago’s medically underserved communities, has encouraged providers to prescribe physical activity.

But research on whether the prescriptions are effective is limited and mixed. A study of Australian women between the ages of 40 and 74 found that exercise prescriptions increased physical activity and quality of life over two years, though falls and injuries also increased.

Choosing specific goals — such as reducing blood sugar by 20 points or improving blood pressure — or setting someone up with a personal trainer was also found to be more effective than just telling someone to go exercise.

“People who aren’t regular exercisers need a lot of guidance,” said Dr. Benjamin.

“You have to empower the patient, give them concrete benchmarks and provide follow-up and feedback,” Dr. Benjamin said.

Despite a burgeoning “exercise is medicine” movement, physicians remain more likely to refer someone to a specialist than to a health club, in part because they may be unfamiliar with fitness and not sure how receptive patients will be, said Indiana University physical activity expert NiCole Keith.

“Unless physicians themselves are athletes they’re not always well educated in this, and it’s a big barrier to effectiveness,” Dr. Benjamin said.

Source:toledoBlade.com

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Caffeine Eases Exercise-Induced Asthma

Caffeine taken within an hour of exercise can reduce symptoms of exercise induced asthma (EIA), characterised by shortness of breath  during sustained aerobic activity.

A large dose equal to nine mg of caffeine per kg of body weight was as effective as an albuterol inhaler in treating or preventing EIA. Smaller amounts also reduced wheezing, coughing and other symptoms of EIA.

Timothy Mickleborough, study co-investigator at Indiana University said no additional benefit was found when caffeine was combined with an albuterol inhaler.

Mickleborough and colleagues have been investigating the efficacy of a number of nutritional factors.

His research has shown that a diet high in fish oil and antioxidants and low in salt has the potential to reduce the severity of EIA and perhaps reduce the reliance on pharmacotherapy.

This is especially important since prolonged use of daily medications can result in reduced effectiveness, and there is growing concern about the potential side effects of inhaled corticosteroid use.

The study was presented at the American College of Sports Medicine conference in Indiana during the Respiratory Session.

Source: The Times Of India

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Fit, Not Frail: Exercise as a Tonic for Aging

Fact: Every hour of every day, 330 Americans turn 60.

Fact: By 2030, one in five Americans will be older than 65.

Fact: The number of people over 100 doubles every decade.

Fact:
As they age, people lose muscle mass and strength, flexibility and bone.

Fact: The resulting frailty leads to a loss of mobility and independence.

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The last two facts may sound discouraging. But they can be countered by another. Regular participation in aerobics, strength training and balance and flexibility exercises can delay and may even prevent a life-limiting loss of physical abilities into one’s 90s and beyond.

This last fact has given rise to a new group of professionals who specialize in what they call “active aging” and an updated series of physical activity recommendations for older adults from the American Heart Association and the American College of Sports Medicine. These recommendations are expected to match new federal activity guidelines due in October from the United States Health and Human Services Department.

But you need not — indeed should not — wait for the government. Even if you have a chronic health problem or physical limitation, there are safe ways to improve fitness and well-being. Any delay can increase the risk of injury and make it harder to recoup your losses.

Miriam E. Nelson, director of the John Hancock Center for Physical Activity and Nutrition at Tufts University in Boston and lead author of the new recommendations, observed last fall in The Journal on Active Aging that “with every increasing decade of age, people become less and less active.”

“But,” Dr. Nelson said, “the evidence shows that with every increasing decade, exercise becomes more important in terms of quality of life, independence and having a full life. So as of now, Americans are not on the right path.”

Jim Concotelli of the Horizon Bay Senior Communities in Tampa, who oversees fitness and wellness program development for communities for the elderly in several states, noted this year in The Journal on Active Aging that many older Americans were unfamiliar with exercise activities and feared that they would cause injury and pain, especially if they have arthritis or other chronic problems. Yet by strengthening muscles, he said, they can improve joints and bones and function with less pain and less risk of injury.

The key is start slowly and build gradually as ability and strength improve. Most important is simply to start — now— perhaps under the guidance of a fitness professional or by creating a program based on the guidelines outlined here.

Although medical clearance may not be necessary for everyone for the moderate level of activity suggested, those with a known or possible problem would be wise to consult a doctor. And a few sessions with a trainer can help assure that the exercises are being done correctly and not likely to cause injury.

Until recently, physical activity recommendations for all ages have emphasized aerobics, or cardiovascular conditioning, through moderate to vigorous activities like brisk walking, cycling, lap swimming or jogging for half an hour a day five or more days a week. For those unable to do 30 minutes at a time, the activities can be broken up into three 10-minute intervals a day. If you have long been sedentary, start with even shorter intervals.

For people who prefer indoor workouts, a treadmill, cross-trainer, step machine or exercise bike can provide excellent aerobic training for the heart, lungs and circulation. Those unable to do weight-bearing exercise might try swimming or water aerobics. Keep in mind that 30 minutes a day of aerobic activity five days a week is the minimum recommendation. More is better and can reduce the risk of chronic disease related to inactivity.

Contrary to what many active adults seem to believe, physical fitness does not end with aerobics. Strength training has long been advocated by the National Institute on Aging, and the heart association has finally recognized the added value of muscle strength to reduce stress on joints, bones and soft tissues; enhance stability and reduce the risk of falls; and increase the ability to meet the demands of daily life, like rising from a chair, climbing stairs and opening jars.

Strength training can be done in a gym on a series of machines, each working a different set of major muscle groups: hips, legs, chest, back, shoulders, arms and abdomen. Or it can be done at home with resistance bands or tubes, hand-held barbells or dumbbells or even body weight. One program, the Key 3 program diagrammed here, was devised by Michael J. Hewitt, research director for exercise science at the Canyon Ranch Health Resort in Tucson. It can be completed in 10 minutes with practice.

 

As Dr. Hewitt explained in the International Longevity Center-USA newsletter, skeletal muscles can only contract and thus are always arranged in pairs. “One muscle of the pair pulls to bend the joint (flexion), and its antagonist pulls to straighten the joint (extension).” Thus, a strengthening program must be balanced, he said, “pairing every pulling lift with an opposite pushing action.”

Dr. Hewitt emphasized that to reduce the risk of injury and premature muscle fatigue, the large muscles should be exercised first, followed by the smaller muscles, with the postural muscles exercised last. For example, one would start with chest and upper back muscles, then the arms and shoulders and finally the lower back and abdomen.

Muscles have to be overworked to grow stronger. The goal for each exercise is three sets of 8 to 12 repetitions to muscle fatigue. Muscles also need time to recover. So strength training should be done two or three times a week on nonconsecutive days.

The new recommendations add flexibility and balance to the mix. Improving balance and reducing the risk of falls is critical as you age — if you fall, break your hip and die of pneumonia, aerobic capacity will not save you. Ten minutes a day stretching legs, arms, shoulders, hips and trunk can help assure continued mobility, and daily exercises like standing on one foot and then the other, walking heel to toe or practicing tai chi can improve balance.

The recommendations, issued last August, are geared to healthy adults 18 to 64, with a companion set for those 65 and older or those 50 to 64 who have chronic health problems or physical limitations. Details can be found at www.acsm.org. Under “Influence,” click on Physical Activity Guidelines From ACSM and AHA.

The experts who made these recommendations urge all adults to adopt them now. As C. Jessie Jones, co-director of the Center for Successful Aging at California State University, Fullerton, said, “People can’t wait until they’re in residential or long-term care to get started.”

Sources: The New York Times

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Will the Wii Keep You Fit?

Wii Fit,” which lets you use the game platform as an exercise tool, is already a runaway hit in Japan and Britain. It was recently released in the United States.

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The newest component of this game is a balance board — a motion-sensitive platform that looks like a double-wide bathroom scale. It can detect how much weight you place on each foot and which way you’re leaning.

Before you start playing, you create a profile, entering your height and age. The game then measures your weight, your body mass index and your “Wii Fit age.” Once you’ve been assessed, you then start your workout, which can include yoga, strength training, aerobics and balance games.
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Sources:

* ABC News May 19, 2008