Heart attacks in the young

“This subgroup of young heart attack patients has a rapidly progressive form of the disease. Unlike the middle aged and elderly heart attack patients, the young infarcts are mainly male patients. According to data available in the Institute of Cardiology, the male-female ratio is 9:1”
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by Dr. D. P. Atukorale

(March 18, Colombo, Sri Lanka Guardian) Heart attacks or coronary heart disease (C.H.D.) appear to have become a serious problem in all the developed and developing countries and is the number one killer in Sri Lanka. For many years it was considered a disease of the people of middle and old age. More recently there appears to be an increasing incidence of heart attacks in young individuals (those below the age of 40 years). More and more young patients with heart attacks have been reported in the Asian countries. (Paul and Siegel, Sing. Med. J; Schettler, Sing Med. J.; Valentine, Sing. Med. J.)
Heart attacks (C.H.D) is a devastating disease because an otherwise healthy person in the prime of life may suddenly die or become disabled without any warning. When the affected person is a very young individual the tragic consequences for the family friends and occupation are particularly catastrophic and unexpected.

Although the incidence of heart attacks (myocardial infarction) in those below 40 years is low (about 3 per cent) according to reports published in the West (H. Jalowiec and Hill, Cardiovas. Clin. 1989, 20, 197-200) the experience of Sri Lankan physicians is quite different. There is a high incidence of young infarcts (young heart attack patients) in Sri Lanka as compared to the more developed countries.

This subgroup of young heart attack patients has a rapidly progressive form of the disease. Unlike the middle aged and elderly heart attack patients, the young infarcts are mainly male patients. According to data available in the Institute of Cardiology, the male-female ratio is 9:1(N.J. Walloopillai and D. P. Atukorale, J. Natn. Sci. Coun. Sri Lanka, 1975.3.19-29) and is same as that in the West.

Age distribution of young Infarcts

In the group we studied in the Institute of Cardiology 2.5 per cent of the patients were below 25 years, 5 per cent between 25-29 years, 27.5 per cent between 30-34 years and 57.5 per cent between 35 and 39 years giving a mean age of 34 + 4.89.

Risk factors

According to the investigations done in the Institute of Cardiology, the commonest risk factor for heart attacks in the young Sri Lankans is heavy cigarette smoking and resulting frequent catacholamine surges damage endothelial cells leading to dysfunction and injury of the vascular intima.

Majority of young infarct patients in our series (64.5 per cent) have been smokers. In the series of young infarcts reported by Paul and Siegel (1973, Singapore Med. J. 14, 339) 95 per cent of were cigarette smokers. In the series of 843 young infarcts reported by Cole et al published in the Journal of American College of Cardiology, February 19, 2003. 215 patients (30.9 per cent) gave a past history of smoking and 268 patients (38.3 per cent) were current smokers.

Hypercholesterolaemia and Hypertriglyceridaemia

According to our Sri Lankan experience’ 30 per cent had hypercholesterolaemia and 30 per cent had hypertriglyceridaemia; The cholesterol values of young infarcts were observed to be significantly higher than those of the controls. The estimation of lipoprotein profile of young infarcts showed that the VLDL (very low density lipoprotein) fraction was higher than that of the controls. In all the cases the lipoprotein estimation was done three months after the heart attack. Elevated VLDL may be a risk factor for heart attacks for Sri Lankans.

Another interesting feature in our series is that the serum triglyceride fraction and the serum VLDL fraction of the relatives of young infarcts was significantly higher than those of the controls. Type IV (WHO) hyperlipoproteinaemia appears to be the commonest lipoprotein abnormality (45%) in our series. Our results are similar to the series reported by Stone and Dick (1973 Br. Heart J, 35, 954). As far as I am aware, the high incidence of hyperlipoproteinaemia in Sri Lankan young infarcts has not been reported by any other Sri Lankan researchers.

In Sri Lanka, as in many other Asian countries low serum HDL (good cholesterol) with or without high levels of serum triglycerides is a risk factor for the high incidence of heart attacks in the young. Unfortunately in 1974 when we carried out the research project on young infarcts there were no facilities to measure serum HDL cholesterol in Sri Lanka and most of the other countries.

Diabetes Mellitus

In the Sri Lankan series the incidence of diabetes was rare (5 per cent) and those few patients were diet controlled diabetics. In the series reported by Oliver (BMT, 1974, 4, 253) only 4 out of 94 patients had abnormal glucose tolerance. In the series of 843 patients reported by Cole et al, 75 patients (9 per cent) were suffering from diabetes. Thus diabetes appears to be an uncommon risk factor for heart attacks in the young.

Systemic hypertension (High Blood Pressure)

Hypertension is a wellknown risk factor for heart attacks in the middle-aged and the elderly patients. In the series reported by Walloppillai and Atukorale 12.5 per cent had past history of hypertension. In the series reported by Cole et al, out of 843 patients below the age of 40 years, 218 patients (26 per cent) had hypertension. Thus the incidence of hypertension in the young infarcts in Sri Lanka is lower than that reported by Cole et al. In 2003.

Obesity

In the Sri Lankan series reported by Walloopillai and Atukorale 22.5 per cent of the patients had obesity. Authors of the Framingham study predict that, for each 10 per cent increase in weight, there is a 30 per cent increase in the incidence of C.H.D.

Family history

In the Sri Lankan series, 40 per cent gave a family history of CHD in the first degree relatives under 60 years. In the series reported by Cole et al, 58 per cent of the young infarcts had a family history of heart attacks. A body of evidence shows that certain disorders of cholesterol metabolism may be genetically transmitted to the off-springs of patients with severe C.H.D.

Cocaine

Cocaine especially taken in combination with tobacco or a concentrated cocaine hydrochloride ("crack") is another risk factor for heart attacks in the young. Cocaine is known to produce spasm, plaque rupture and thrombosis resulting in heart attacks. As far as I am aware, no heart attacks due to use of cocaine has been reported in Sri Lanka.

Ethanol (alcohol) intoxication

This has been responsible for causation of heart attacks in the young; in the presence of normal coronary arteries and in the absence of stimulants, coronary vasospasm is strongly suspected (Williams et al, Heart, 1998, 79, 191 - 4). Coronary angiograms in these young heart attack patients have been found to be normal. As far as I am aware no cases of young infarcts following acute alcoholic intoxication has been reported in Sri Lanka.

Other miscellaneous risk factors

Hyperhomocysteinaemia (high serum levels of homocystein), elevated serum levels of fibrinogen and abnormal blood viscocity are other known risk factors for heart attacks in the young. Other rare causes of heart attacks in the young are coronary dissection, hypercoagulable states and certain connective tissue diseases (collagen vascular disorders).

Other risk factors which may be important in case of young infarcts are emotional disroders, anger and sudden extreme physical exertion.

Another important risk factor in case of young infarcts is inflammation (vasculitis) either measured by systemic inflammatory markers such as high sensitively Creactive protein. Clamydia, mycoplasma and H-pylori are often thought of as having a pathogenetic risk in CHD in the young.

Young women with heart attacks

Young females with heart attacks comprise an interesting group. It is common knowledge that females are less liable to get heart attacks before menopause because of the protective action of oestrogens. In the groups of 843 patients below the age of 40 years reported by Cole et al, there were 94 females (10 per cent). In the above series there were 66 female smokers. In the series reported by Walloopillai and Atukorale there were no smokers. Smoking is very rare among Sri Lankan females.

Use of contraceptive pill

Use of contraceptive pill is a rare risk factor for heart attacks in females. Truncal obesity and increased body mass index (BMI) are other risk factors for heart attacks in the young females.

Prognosis of young infarcts

Compared to the middle-aged and elderly heart attack patients, prognosis (prospect of recovery) of young infarct patients is very much better-as majority of them have less extensive atherosclerosis (irregular deposition of substances such as cholesterol and triglycerides on the inner wall of arteries and arterioles causing narrowing of affected blood vessels) as compared to the elderly heart attack patients.

Majority of young infarct patients who survive the heart attack have less damage to the heart muscle and as such their led ventricular function is better than that of older patients. The percentage of young infarct patients having blockage of only one coronary artery is higher than older heart attack patients who frequently have blockage of more than one coronary artery. The group of young infarcts has a substantial vasopastic component superimposed in a genetic predisposition to vulnerable plaque production. Conversely a second group is comprised of those with diabetes and those with multivessel disease (including those related to high cholesterol states) and these patients have a bad prognosis in spite of bypass surgery (Lloyd W. Klein and Sandeep Nathan, J.A.C.C, Vol. 41, 2003, 529-31).

- Sri Lanka Guardian