Heart attack

Friday, 23 June, 2000, 10:12 GMT 11:12 UK

Heart attack

Massage may be used after a heart attack

A heart attack occurs when blood flow to part of the heart is blocked, often by a blood clot, causing damage to the affected muscle.

This is usually caused by atherosclerosis - hardening of the artery walls. The clot, often caused by rupturing or tearing of plaque in an artery is sometimes called a coronary thrombosis or a coronary occlusion.

If blood supply is cut off for a long time, muscle cells are irreversibly damaged and die, leading to disability or death depending on the extent of the damage to the muscle.

A heart attack, also known as myocardial infarction, can also occur when a coronary artery temporarily contracts or goes into spasm, decreasing or cutting the flow of blood to the heart.

An unexpected and abrupt heart attack occuring soon after the onset of symptoms can result in sudden death.

It accounts for about half of all coronary heart disease deaths and can be caused by nearly all types of heart disease.

Three main symptoms of a heart attack:

• 1. Pressure or pain in the centre of the chest, lasting more than a few minutes or going away and coming back
• 2. Pain spreading to the shoulders, neck or arms
• 3. Chest discomfort combined with light-headedness, fainting, sweating, nausea or shortness of breath

What to do if someone has a heart attack

Check the victim for a response If no response, ask someone to call for an ambulance. If you are on your own, do this yourself; you may need to leave the victim Check the victim is breathing normally If breathing is normal, place them in the recovery position and await help If not, open their airway using a head tilt and chin lift and begin 30 chest compressions Open the airway again and give two rescue breaths (mouth to mouth) Continue the chest compressions and rescue breaths in a ratio of 30:2 For detailed instructions, visit the Resuscitation Council website.

Other common warning signs of heart attack include unusual chest, stomach or abdominal pain, nausea or dizziness, shortness of breath or difficulty breathing, unexplained anxiety, weakness or fatigue, palpitations, cold sweat or paleness.

Anybody experiencing these symptoms should call an ambulance immediately, but should not try to drive themselves to hospital, as complications can begin to occur before they get there.

Most people do have time to get to hospital and be treated before collapsing, but they do need to act quickly.

Some people wait for hours or even days before seeking help - they are the ones that get into trouble.

After a heart attack

Diagnosis of a heart attack usually involves a clinical examination, an electrocardiogram, heart rhythm monitoring and blood tests.

Echocardiograms or angiograms will detect the extent of damage to the heart.

Immediately after a heart attack, clot-busting drugs will be used to restore blood flow. Aspirin, to aid blood flow, and beta-blockers, to ease the heart's work rate, may also be used.

In the days or weeks after a heart attack, surgery - either angioplasty or coronary artery bypass surgery - may be performed.

Celebrating the UK's computer pioneers

The computer seems the very essence of the modern world, especially as the gadgets we sit before and carry around shrink as fast as they become more powerful.

But if truth be told the computer has had a long and honourable history that stretches back to the closing years of the World War II.

And, say conservations and computer history enthusiasts, Britain played a big part in the development of the modern computer.

"The layman when asked about the introduction of steam power will usually reel off Newcomen, Watt and Trevithick," said Chris Burton, of the Computer Conservation Society.

"But when it comes to computer pioneers they are absolutely baffled," he said. "They have no idea."

Foundational work

When pushed, he said, they might be able to remember the name of Alan Turing but few know of any others beyond that.

Turing established the conceptual and philosophical basis for the rise of computers in a seminal 1936 paper called "On Computable Numbers". But it took a large cast of engineers and scientists to solve the real world problems that arise when those ideas are turned into whirring, clicking reality.

At Bletchley Park forerunners of modern computers were built to help the Allies crack German codes.

Colossus was crucial for D-Day operations

Although Turing worked at Bletchley and helped create the Bombe that cracked messages enciphered with Enigma machines he had little to do with Colossus - a programmable machine that tackled the encrypted messages sent by the German High Command.

Conceived, designed and built by Tommy Flowers, Allen Coombs and Max Newman, the first Colossus was working in 1943 - three years ahead of the rival pioneering American machine known as Eniac.

For a long time the Electronic Numerical Integrator And Computer (Eniac) was better known than Colossus because the Official Secrets Act prevented those that worked on it talking publicly about their achievements.

Kevin Murrell, a trustee for the National Museum of Computing where a rebuilt Colossus is housed, said Bletchley was just one of the locations where the UK's computer pioneers did their influential work.

Colossus, he said, amounted to about one-third of all effort being put into those early machines. Similar pioneering efforts were underway at Manchester and Cambridge.

Cakes and computers

At Cambridge, Maurice Wilkes and his colleagues were working on the Electronic Delay Storage Automatic Calculator (Edsac) - another recognisably modern machine that used tubes of mercury five feet in length as a data storage medium.

Edsac ran its first programs in 1949 and was developed to act as the heart of a number crunching service for Cambridge scientists.

Some principles of computing date from Victorian times.

The creation of Edsac was backed by baking and catering giant J Lyons which bought a copy of the finished machine and turned it into the world's first business computer - the Lyons Electronic Office (Leo).

"It was the first programmable computer that went into routine operation," said science writer Georgina Ferry, author of a book about the genesis of Leo.

"What was innovative about Leo was not the hardware," she said, "but the systems and the way they used it."

John Pinkerton, David Caminer, Ernest Lenaerts, Derek Hemy and others at Lyons pioneered the use of computers in the dull repetitive tasks formerly carried out by legions of clerks. One of its first roles was to calculate how much each worker at the hundreds of Lyons tearooms was to be paid.

Steadily more and more of those basic tasks were studied by Caminer and his team and broken down into steps Leo could replicate. In the process Caminer and his colleagues created systems engineering.

"Leo led the world in business computing," she said.

Big baby

At the University of Manchester engineers such as Tom Kilburn, Freddie Williams, Geoff Tootill, Alec Robinson, Dai Edwards and others worked to create what became the Small Scale Experimental Machine (SSEM) or Baby.

The Baby was recognisably modern electronic computer because it could easily be re-programmed to carry out different tasks. By contrast older machines either just carried out one function or had to be re-wired to change what they did.

A replica of the original Baby now resides at the Museum of Science and Industry in Manchester.

"When we wrote the proposal to build the replica machine an explicit goal which was to re-run the first program as a tangible tribute to the pioneers that brought this about," said Chris Burton who led the effort to re-build the SSEM.

Mr Burton said none of them had any idea about the influence their work would have.

"They did it to help engineers, forecasters and scientists to do their calculations," he said. "They had no idea of the fantastic proliferation that we have had since."

Nasa launches its Aura satellite

The US space agency has successfully launched its Aura satellite which is designed to check the health of the Earth's atmosphere.

The satellite blasted away from Earth on a Boeing Delta 2 rocket from Vandenberg Air Force Base at 1002GMT.

A problem with the rocket's battery system stopped the countdown three minutes before lift-off on Wednesday.

Aura will peer through the stratosphere and troposphere, to study in detail the thin layer of gas in which we live.

We are now bracing ourselves for the arrival of many gigabytes of data Hugh Pumphrey, University of Edinburgh

Launch attempts on Sunday and Tuesday were also scrubbed because of technical issues, first with the rocket and then with its payload.

'Very useful tool'

Among its many tasks, Aura will test whether international atmospheric treaties, such as the Montreal Protocol to repair the ozone layer, are working.

The spacecraft promises significant returns for climate studies

Nasa describes the spacecraft as one of the most sophisticated environmental monitoring satellites ever built.

It is the third in the agency's series of satellites aimed at providing definitive data on the global environment.

The first two, Terra and Aqua, are studying the ground and the oceans. Aura will concentrate on the atmosphere, looking at gases, pollutants, and chemical reactions.

The three-tonne spacecraft will help scientists understand how atmospheric composition affects and responds to Earth's changing climate.

"Aura's going to be very helpful in tracking whether the ozone layer is recovering, in establishing the relationship between particulates and atmospheric gases and climate change; and Aura will hopefully also be a very useful tool in developing better predictions of air quality," Rick Pickering, Aura Project Manager at the Goddard Space Flight Center, told BBC News Online.

Climate complexity

Last year, scientists produced the first concrete evidence that the ozone layer is in the process of recovering (even if the hole is presently getting bigger) after decades of damage caused by substances like CFCs.

But a return to full health will take about 50 years by current estimates - and global warming could change that timescale.

On climate change itself, one outstanding issue is the role of tiny particles in the atmosphere.

The ozone "hole" is still growing - but not as fast as it once was

These aerosols, typically containing sulphur or carbon, come from natural sources, such as volcanoes, and from human sources, such as the soot from fossil fuel burning.

Aerosols are an important but uncertain agent of climate change. By absorbing or scattering radiation, they can either warm or cool the troposphere. They can also modify clouds and affect precipitation.

If Aura can help scientists understand precisely what these particles are doing, how they behave and what they mean for the future of the global climate, that would be a significant return on the satellite's billion-dollar cost.

Aura has four instruments, the High Resolution Dynamics Limb Sounder (HIRDLS); the Microwave Limb Sounder (MLS); the Ozone Monitoring Instrument (OMI); and the Tropospheric Emission Spectrometer (TES).

The HIRDLS and MLS were built with a substantial UK contribution.

MLS scientist Hugh Pumphrey, from the University of Edinburgh, was pleased to see Aura finally fly.

"We watched the launch over the internet earlier today and, having broken out the champagne (which has been in and out of the fridge several times over the last few days) we are now bracing ourselves for the arrival of many gigabytes of data."