One in four elderly Singaporeans who suffered a stroke could have prevented the attack if their underlying heart problems had been treated with a device like a pacemaker.

But the number of people here with pacemakers - a small electronic device that regulates heartbeats - is low compared to most other developed countries, said Dr Teo Wee Siong, a senior consultant at the National Heart Centre Singapore (NHCS).

Speaking at last week's Heart Rhythm meeting which attracted close to 1000 delegates from 39 countries, Dr Teo said only 91 out of a million people here had a pacemaker fitted in 2005.

In most developed countries, the rates are well above the 300 per million, with countries such as the United States, Belgium, France and Italy topping 700. This is partly due to their older population.

Dr Teo said the low take up rate here is largely caused by lack of knowledge - on the part of both doctors and patients - since cost is not a factor, given the large government subsidies for the devices.

A pacemaker costs from $3000 for a basic unit to $15,000 for a more sophisticated model.

They are placed under the skin or in the abdomen and connected to the heart. It is a simple operation that takes about an hour or two. 

More than 3000 people here are walking around with pacemakers, including Minister Mentor Lee Kuan Yew, who had one fitted last Saturday.

About 400 to 500 people here have pacemakers put in each year. These devices, which have been in use for half a century are generally very safe. 

They are used to regulate heartbeats that are too slow, too fast, or irregular. 

Such conditions, called arrhythmias are benign in many people. But in others it can lead to a stroke, or sudden death. 

Dr Teo, director of electrophysiology and pacing at the NHCS, specialises in the electrical impulses of the heart. When these are faulty, several things can happen.

A common arrhythmia is atrial fibrillation, where the upper heart chamber is no longer able to pump out blood. 

While the blood continues to flow out of the heart, it is sluggish. After some time, the blood starts forming clots, which could flow to the brain and cause a stroke.

A pacemaker gets the upper chamber to pump normally, by sending the correct electrical signals to activate it.

If the problem is in the lower heart chamber, the heart can flutter uselessly. Unless it is shocked back into proper action, it could stop working altogether within minutes.

To deal with this problem, cardiologists put in an implantable cardioverter defibrillator ICD. 

Aside from acting as a pacemaker, it is also able to shock-start a heart that has stopped.

These defibrillators are more expensive costing from $10,000 to $50,000 each. They also carry slightly more risk, such as shocking the heart unnecessarily and should not be used unless patients are at risk of sudden death.

Currently about 70 to 80 people each year get a defibrillator implanted. Among them are some teenagers who face a high risk of suffering a fatal heart attack.

Singapore has seen several cases of apparently fit young men dying suddenly. An ICD could have saved many of these lives.

Dr Teo, who carried out the first defibrillator implant here - in 1992 at Singapore General Hospital - estimates 200 people here might need one each year.

He said that often, patients do not realise the seriousness of the symptoms they have such as fainting spells, near blackouts and breathlessness after walking.

Many people put the symptoms down to growing older, and in some cases, that might be true, he pointed out.

But these symptoms could also mean the heart chambers are not beating properly. So these people should have their hearts checked to see if they need either a pacemaker or an ICD, he said.

Source: The Straits Times © Singapore Press Holdings Limited. Permission required for reproduction.