In some people, high blood pressure leads to the heart muscle thickening and scarring in a matter of years, eventually resulting in heart failure.
But to the bafflement of doctors, others live with high blood pressure for most of their lives, with little discernable impact on their hearts.
This is why doctors at the National Heart Centre Singapore (NHCS) are recruiting 500 people for a 10-year study to find out how common fibrosis - or scarring - is, and what makes some people more likely to get it. Anyone with high blood pressure - no matter how mild or severe - can join, as long as they have not had a stroke, heart attack or heart failure.
In Singapore, between 60 per cent and 80 per cent of those diagnosed with heart failure have high blood pressure, said Assistant Professor Calvin Chin, who is the study's principal investigator. This is because high blood pressure makes the heart work harder, thickening its muscles.
"The muscle cells don't get enough oxygen and they die and are replaced by scar tissue," explained Prof Chin, who is also a consultant at NHCS. "This can lead to heart failure, which makes sense because the scarring means the heart is not able to pump as well."
The goal of the study, Prof Chin said, is to find out what makes certain people more prone to such scarring, and intervene for this group before it is too late. Those who are part of the study will undergo a free magnetic resonance imaging (MRI) scan on their hearts and have their blood drawn. They will also be given a blood pressure monitoring device, which will record their blood pressure for the next 24 hours.
The centre will follow up with an annual phone call over the next 10 years to ask if they have had any major heart problems in that time.
"Two patients can have similar blood pressure, but one can progress to fibrosis and heart failure very quickly," said Prof Chin. "But we still don't know if it is (because of) medication or other risk factors."
Those who are interested in taking part in the study can e-mail NHCS at firstname.lastname@example.org