Risk factors of heart attack
Heart disease and High blood Pressure
Hypertension is called a silent killer and it has been established as a major modifiable and unequivocal risk factor for heart attack. High blood pressure or hypertension is a very common disease which affects approximately 10-14% of the adult population. If left untreated it can lead to disastrous complications like heart attack, stroke, heart failure, renal failure etc. Many people with high blood pressure do not have any symptoms or ill effects and the disease remain silent for many years until a major complication like heart attack occurs. The Framigham Heart Study demonstrated that patients with high blood pressure have twice the risk of sudden heath, myocardial infarction (heart attack) as do normotensives. Once upon a time doctors believed hat 160/95 mm of Hg is top normal level of blood pressure for adult population. So they did not recommend continuous treatment if blood pressure of patient was found below 160/95. But the above recommendations have changed in the recent past. 5th joint national committee of America recommends that any person whose blood pressure is more than 140/90 mm of Hg require anti-hypertensive treatment. Treating patients with blood pressure more than 140/90 mm of Hg is praiseworthy. Such treatment reduces the unfortunate death from stroke and heart attack.
During expressing blood pressure
doctors use two readings, the upper one is called systolic blood pressure and
the lower one is called diastolic blood pressure. The heart is a pump and its
automatic rhythmic contraction and relaxation makes the blood to circulate in
the body through the arteries. Each contraction of the heart generates a
pressure wave in the arteries and this can be recorded easily in the upper arm
by using a blood pressure measuring device called sphygmomanometer. The
pressure generated at the peak of contraction is called systolic pressure
(upper reading). When the heart relaxes, the pressure in the arteries falls to
a lower level called the diastolic pressure. Hence blood pressure is usually
expressed as a ratio of the systolic pressure over the diastolic pressure e.g.
120/80 mm of Hg. Recent data have suggested that diastolic blood pressure
(lower reading) has a primary impact on risk of stroke (brain haemorrhage),
whereas systolic (upper reading) is more closely to risk of coronary heart
disease.
The blood pressure in a healthy
person can vary a great deal depending on the patient’s age and physical built.
Blood pressure also varies with physical activity. During exercise the blood
pressure, specially the systolic or upper reading rise considerably to meet the
increased oxygen requirement of the body. Hence it can sometimes be quite
difficult to determine whether a person is truly suffering from hypertension.
To make a diagnosis of hypertension the blood pressure must be recorded at rest
and doctor may have to take several readings, at the same visit or at multiple
visits to make a definite diagnosis. It has been found that in some persons the
blood pressure fluctuates from time to time, some times they are hypertensive
and sometimes normotensive, this is called labile hypertension which is often
not harmful. Some patients when record their blood pressure in home atmosphere,
they are found to be of normal pressure but when they go to a doctor for
checkup their blood pressure rise seeing the doctor, this is called white-coat
hypertension. Doctors usually wear white apron and seeing this apron the
patients become apprehensive and their blood pressure goes high. Now a days
whether a person is really hypertensive, can be documented by Ambulatory blood
pressure measurement. It is a small machine like a wireless set, they the
patient wears along with a cuff around the arm. The electronic recorder measures
continuously the 24 hour blood pressure. After monitoring 24 hours a doctor can
take correct decision whether the person is hypertensive or not.
According to US Joint National
committee report high blood pressure is divided into three categories according
to the diastolic pressure (lower reading). Diastolic blood pressure between 90
and 104 mm of Hg constitutes mild hypertension, a diastolic pressure 105 and
114 mm of Hg constitutes moderate hypertension and a diastolic pressure over
114 mm of Hg defines severe blood pressure. But now a day’s blood pressure is
classified in to 4 grades, but this classification appears difficult to understand
for the non medicos.
Hypertension or high blood pressure
may cause coronary artery disease by few ways. High blood pressure produce
small injuries to the lining of the coronary arteries which is key event in the
formation of atheroma an ultimately thrombosis (total block). Gradual damage of
the coronary arterial system may lead to heart attack. If blood pressure remains
persistently high then it produces numerous small injuries and gradually blocks
the blood supply of the heart. Due to high blood pressure heart muscle
gradually become thicker and it is called ventricular hypertrophy. Numerous
anatomical and functional studies have demonstrated coronary artery
abnormalities if the left ventricular wall become thicker than normal . High
blood pressure bas been associated with an increased tendency towards rupture
of the lining of the fat deposit (plaque rupture) inside the coronary artery
and produces total block of the coronary artery.
