Questions from the heart

LAST week, I gave a talk on ensuring a healthy heart at a public symposium organised by The Business Times and Mount Elizabeth Novena Hospital. The responses to some of the common questions from the public are captured in this article.

I exercise daily and have good control of my cholesterol levels. Why is it that I still get blockage of the heart arteries?

Studies have claimed that 40 per cent to 60 per cent of susceptibility to heart artery disease is inherited. Data from the Framingham Study and the INTERHEART studies have shown that a family history of heart artery disease is associated with a 1.5 to >2 times increased risk of heart artery disease. A genetic risk variant identified that is associated with increased risk of heart attacks is located at the ABO blood group genetic site. In the Nurse's Health Study on more than 90,000 patients followed up for 20 years, the presence of blood group A or B was each associated with a 10 per cent increased frequency of heart attacks and the risk was increased about 20 per cent for those with both A and B blood groups. Those with A and B blood groups produce a protein that modifies the blood clotting factor termed von Willebrand Factor (vWF) thereby increasing the duration in which it remains in the blood stream and hence the level of vWF is about 25 per cent higher in those with blood groups A, B and AB when compared to those with blood group O. As the main mechanism of heart attack is the formation of a blood clot which then obstructs the residual lumen of the narrowed heart artery, increased levels of blood clotting factor will increase the probability of blood clot formation and thereby increase the likelihood of a heart attack. In addition, it has been est…