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.
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)
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
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 )
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,
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)
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)
The information contained here is not a substitute for medical advice or treatment or replaces consultation with your doctor.
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