BBC World Service reporter
Despite advances in medicine that make many heart conditions treatable, the absence of effective, early diagnosis often leads to sudden, unexpected deaths.
In the Irish Republic, where two people under the age of 35 die from cardiac ailments every week, scientists are working on a new stethoscope that picks up a wider range of heart sounds.
The researchers say they believe the device will lead to more rapid diagnosis of coronary artery disease.
They hope such diagnoses will be eventually carried out in GPs' surgeries.
Mary Desmond Vasseghi lost her son Darius three years ago.
Of mixed Irish and Iranian parentage, the 18-year-old was found dead on the floor of the bathroom one morning by his twin sister.
Darius was a healthy, active sportsman and student, full of the vigour of life.
"He had participated in the world fencing championships, he was Irish champion, he was part of the team, a brilliant student," says Mary.
"These are all the things that people spoke about, but more importantly he was just about the nicest person you could ever meet. He was a really nice guy."
No idea of problem
Mary says that despite the fact that Darius had a medical check up every year, no-one had any idea that her son had a heart problem.
Even now there is uncertainty about the exact cause of death.
"What we discovered was that Darius had an undiagnosed cardiac condition, " said Mary.
"We still don't know the full diagnosis, we are presuming it was a problem with the electrics in his heart."
The tragic loss of Darius was instrumental in driving forward new research at his university in Dublin aimed at improving detection and diagnosis of hidden heart problems.
One of those leading the work at University College Dublin is Dr Scott Rickard, a US scientist with a sparkling academic pedigree in applied mathematics and electrical engineering.
As an expert in audio identification techniques his work brought him to the attention of the FBI, where he helped develop an eavesdropping technology to identify a speaker's location in a crowded room.
Using two closely spaced microphones, it was possible to separate and localise an arbitrary number of speakers.
"So if you were in a room and 10 people were speaking, you could tell who said what, when," said Dr Rickard.
"That is really important for the FBI - they have lots of recordings of people and they want to know what was said and who said it."
But detecting heart disease just by listening is an altogether more difficult exercise.
According to Dr Rickard the number and complexity of sounds coming from the heart area make it very hard to reliably determine the cause.
His approach was to form a multi-disciplinary team, including an expert in volcanic lava flows as well as heart specialists.
Together they have designed and built a new "super" stereo stethoscope that uses six microphones instead of one.
Dr Rickard said: "It is essentially just six little round microphones about the size of a US quarter, connected to a computer.
"On the screen you can see the lub, dub sounds of your heart, a little peak for the lub and a little peak for the dub evolve across the screen."
Hidden between these peaks are the sounds that can tell a great deal about heart disease.
Dr Rickard uses a musical analogy to describe them: "We might all hope that our hearts sound like Mozart, unfortunately at some stage they might sound like Metallica.
"We are building a detector that basically tells the difference between Mozart and Metallica - that might seem easy but it's not."
The device is now being used by a team of cardiologists at St Vincent's hospital in Dublin.
The research team are collecting data to bolster the scientific credentials of the new stethoscope.
There have been many attempts to develop new technologies to detect cardiac problems - most have failed.
While the stereo stethoscope has a number of advantages, such as its ability to identify the type as well as the location of a fault, there is no guarantee that it will succeed.
But Dr Rickard is an optimist. He says that if the technology can be shown to work, then it should be powerful enough and robust enough to diagnose even the most difficult heart conditions.
"The original project was not to just to detect coronary heart disease but to detect any heart abnormality, the idea being that this should be in every GP's office, you go in to the GP with a cold and they should just stick this little multi-channel stethoscope to your chest," he said.
"They listen to your heart and they should be able to diagnose a myriad of different things, not just coronary heart disease but congenital heart defects that go unnoticed simply because people aren't listening.
"So many people suffer from this and you could really increase the quality of many people's lives by catching them early and turning them back rather than having them walk off the cliff as we currently do."
For parents like Mary Desmond Vasseghi who have lost a child to an undiagnosed cardiac condition, technology like that being developed at UCD is the way forward.
"All we need is a diagnosis, an accurate diagnosis," said Mary.
"With the technology of today, diagnosis can leave grey areas for even the best specialists in the world.
"What needs to be understood is that many of these heart conditions can be treated, once you diagnose them accurately.
"For the moment we do have the treatment - but we don't have the technology to do a proper diagnosis."