Normal ABP : the pressure exerted by blood on the vessel wall of the arterial system from the beginning of the aorta to the start of the arterioles, it is about 120 mmHg systolic and 80 mmHg diastolic.
Arterial blood pressure (ABP) = cardiac output (CO) X total peripheral resistance
Hypertension : sustained elevation of the systemic ABP > 139 mmHg systolic & > 89 mmHg diastolic. Therefore : so long as CO is constant is relatively constant ; a change in the ABP is mainly due to a change in the peripheral resistance.
Grades of hypertension
|Category |Systolic |Diastolic | |Optimal |< 120 |< 80 | |Normal |< 130 |< 85 | |High-normal |130 – 139 |85 – 89 | |Hypertension grade 1 (mild) |140 – 159 |90 – 99 | |Hypertension grade 2 (moderate) |160 – 179 |100 – 109 | |Hypertension grade 3 (severe) |> 180 |> 110 | |Isolated systolic hypertension |> 140 |< 90 |
Types of hypertension
1- Primary (Essential) hypertension (about 95 %) : unknown cause Heredity : interaction of genetic , environmental and demographic factors Excess sodium intake : about 20% of patients develop hypertension : salt sensitive hypertensives.
Sedentary lifestyle is responsible for the exploding increase of HTN in economically developing regions ‘Westernization’ e.g obesity, and alcohol intake.
Increased sympathetic activity : is thought by some...