Stable
plaque
Ruptured plaque
Acute
thrombosis
Misconception
1
Most heart attacks are due to sudden blockage of heart vessels
which are severely blocked
Not true.
Until the early 90’s cardiologists
believed this to be true, but when
studies were conducted with clot dissolving medications such as streptokinase,
it was discovered that about 65-70% of heart attacks were due to the
so-called “insignificant” narrowing of arteries which are less than 5o%
blocked. Recent
studies have established that most heart attacks are caused by rupture or
erosion of an unstable plaque. The culprit lesions are usually mild blockages of
<50%.
An
unstable plaque has the following characteristics:-
Thin
fibrous cap which can tear, ulcerate or rupture, and a soft lipid core. When an
ulceration
or tear in an unstable cholesterol plaque happens, there is sudden clot
formation and complete blockage of the artery.
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Misconception
2
Atherosclerosis or hardening of the arteries, which causes heart
disease, begins at about the age of 40.
Not true.
Many people believe so but the truth is atherosclerosis starts as early as childhood, and is
already evident by the time a person reaches 20.
A recent study looking at the prevalence and
extent of atherosclerosis in the adolescents and young adults found that ......in 2876
autopsies of accident victims age 15-34 years old, fatty streaks was seen in the
aorta in 99.93%, and atherosclerosis was already evident in the heart arteries
in 50% of teenagers age 15-19 yrs old.(Strong
JP ET al JAMA1999; 281:725-35)
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Misconception
3
If you keep your cholesterol level within normal ranges, you will
be safe from getting a heart attack
Not true. A high cholesterol level is a definite risk factor for heart
disease.
However most patients with heart
attacks have normal or borderline cholesterol levels (200-220mg/dl,
5.2-5.6 mmol/L) and only 30% have high cholesterol levels. (ref:
Rumberger et al Mayo Clinic Proc 1999; 74:243-252) One
should not be complacent even if one has a normal cholesterol level.
In
the Framingham Heart Study, an epidemiological study on prevalence of heart
disease, the percentage distribution of
serum cholesterol levels in males who did or did not subsequently develop
coronary heart disease was almost
identical
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Misconception
4
Majority of heart attacks occur in people with chest pains and
these signs will appear weeks before the actual event.
Not true. Most people think that if
they have no symptoms they do
not have heart disease. This is the reason why heart disease is called the
Silent Killer.
In a study on what were the first signs or symptoms of heart disease,
typical angina or chest pains occurred in only 10%of patients, 70%
had no warning signs, in 35% death was the first and last symptom.
(Thaulow - American
Journal of
Cardiology; 1993:72:629
)
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Misconception
5
Your treadmill stress ECG was normal, therefore you don’t have
heart disease and will not get a heart attack
Not true.
This is because signs and symptoms
of coronary artery disease will
appear only when the narrowing is greater than 75%
Many people feel reassured when they have a
negative treadmill exercise stress test and doctors traditionally use this test
to detect coronary artery disease.
But what does the American College of Cardiology and American Heart Association GUIDELINES FOR EXERCISE TESTING tell us about this test?
Stress testing detects abnormality in heart
function caused by obstructive narrowing of heart arteries
of GREATER than 75%.
The Guidelines states that Exercise Stress Testing
is most useful for diagnosis of obstructive
coronary artery disease in a
dult patients with an
intermediate pretest probability of CAD, based on gender, age, and symptoms.
In other words, adults with
chest pains. But unfortunately it is not useful
if you do not have any symptoms.
It is also important to realize the test’s limitations. How sensitive and accurate
is the exercise test?
This test will pick up 68% of patients with blocked coronary
arteries but 32% can be missed,
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Misconception
6
If you have no risk factors and lead a stress free lifestyle,
then you will not develop heart disease
Not
true.
Conventional risk factors listed below, of which cholesterol is but one, puts a
person at 2-3 times increased risk of having coronary artery disease.
-
Age
-
Sex
-
Family History
-
Cigarette
smoking
-
Obesity
-
Hypertension
-
Diabetes mellitus
-
Physical Inactivity
-
Cholesterol
-
High LDL Cholesterol
-
Low HDL Cholesterol
Conventional risk factors help to identify only 70% of heart
patients
. 30% of heart attack patients do not have
any conventional risk factors
. Conventional risk factors are also poor predictors of future
heart attacks or death. (Wald et alLancet 1994;343:15-19; Grover
et al JAMA 1995; 274:801-806)
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Misconception
7 After balloon angioplasty or bypass surgery a heart patient
is “cured” and will not suffer from any more heart attacks
Not true. Angioplasty or bypass surgery alleviates symptoms but does not cure
the atherosclerotic plaque disease. The plaque is still present and the patient
is still at risk. That is the
probably the reason why no long term follow up study has shown that angioplasty
and bypass surgery in stable angina patients improved survival nor prevented
future heart attacks compared to medical therapy alone. (Ref:
RITA trial, AVERT trial)
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The information contained in this website is not a substitute
for medical advice or treatment or replaces consultation with your doctor.
