Obstructive Sleep Apnea may be signs of heart attack
By Alicia Wong, TODAY | Posted: 30 June 2009 0855 hrs
Excessive daytime sleepiness, morning headaches and an inability to concentrate – these may not seem like early warning signs of a heart attack.
But a study from Singapore’s National University Hospital found that male patients with Obstructive Sleep Apnea (OSA), who would have these symptoms, are more likely to develop heart attacks.
Two-thirds did not know they had OSA, which refers to complete or partial obstruction of the upper airway during sleep.
This was found after an overnight sleep study of 105 acute heart attack patients, of whom 98 per cent were men. The study was conducted over two to five days between January 2007 and April last year.
“The results were very surprising. This data was never known before in literature,” said NUH Heart Centre consultant Ronald Lee.
It is known that OSA patients are more likely to have hypertension, platelet clotting dysfunction and diabetes – which are all in the family of heart disease, he said.
But while previous studies had examined patients with a variety of heart diseases, this study focused solely on Asians who suffered heart attacks.
“The main message… is that these two conditions go hand-in-hand. Sleep apnea is still a relatively under-diagnosed condition in the community,” said Dr Lee.
While patients often think it is an isolated condition, he added, studies have shown that heart disease patients with OSA are more likely to have a recurrence of their heart disease even after ballooning procedures.
Philips Electronics Singapore has also called for more education on the sleep disorder, which affects 15 per cent of Singaporeans.
Its recent study in five countries (Japan, the United States, the United Kingdom, Germany and the Netherlands) revealed that two-thirds of 2,500 respondents considered snoring, a key symptom of OSA, a minor inconvenience that need not be dealt with.
OSA sufferers also unknowingly stop breathing repeatedly while asleep.
With OSA affecting 13.6 per cent and 4.3 per cent of men and women in Singapore respectively, studies show “this is significantly higher than the Asian prevalence of symptomatic OSA in middle-aged men (4.1 to 7.5 per cent) and women (2.1 to 3.2 per cent)”, said Philips in a statement last week.
Singapore Sleep Society president Lim Li Ling said, “Our practical experience suggests that chronic partial-sleep deprivation is common, and sleep apnea is one of the major sleep problems.”
Those experiencing symptoms such as heavy snoring, morning headaches and impaired concentration should get checked by a doctor, advised NUH’s Dr Lee.
Patients are treated by Continuous Positive Airway Pressure therapy, which gently pushes air through the nasal passage using a mask. This prevents the airway from collapsing.
“With proper diagnosis and treatment, OSA can be eliminated to greatly improve the quality of sleep and health,” noted Dr Khoo See Meng, a consultant at NUH’s division of respiratory and critical care medicine. “If untreated, OSA may lead to high blood pressure, heart attack or heart failure.”
Separately, the NUH study, which was published this month in Chest, the official journal of the American College of Chest Physicians, found that diabetic patients are three times more prone to OSA. The team is now exploring whether OSA contributes to any long-term negative impact on heart attack patients.