diastolic pressure

(noun)

The minimum arterial pressure between contractions, when the heart expands and refills.

Related Terms

Examples of diastolic pressure in the following topics:

  • Measuring Blood Pressure

    • Measurement of blood pressure includes systolic pressure during cardiac contraction and diastolic pressure during cardiac relaxation.
    • It is recorded as two readings: the systolic blood pressure (the top number) occurs during cardiac contraction, and the diastolic blood pressure or resting pressure (the bottom number), occurs between heartbeats when the heart is not actively contracting.
    • A normal blood pressure is about 120 mmHg systolic over 80 mmHg diastolic.
    • These pressures, called segmental blood pressures, are used to evaluate blockage or arterial occlusion in a limb (for example, the ankle brachial pressure index).The difference between the systolic and diastolic pressure is called the pulse pressure.
    • A blood pressure cuff and associated monitor used for determining systolic and diastolic pressures within an artery.

  • Introduction to Blood Pressure

    • Blood pressure is the pressure that blood exerts on the wall of the blood vessels.
    • Two mechanisms take place in the heart: diastole and systole.
    • Diastole is the relaxation of the chambers of the heart and systole is the contraction of the heart chambers.
    • Systolic pressure is thus the pressure that your heart emits when blood is forced out of the heart and diastolic pressure is the pressure exerted when the heart is relaxed.
    • During each heartbeat, blood pressure varies between a maximum (systolic) and a minimum (diastolic) pressure.

  • Arterial Blood Pressure

    • Pressure is typically measured with a blood pressure cuff (sphygmomanometer) wrapped around a person's upper arm, which measures the pressure in the brachial artery.
    • A person's blood pressure is usually expressed in terms of the systolic pressure over diastolic pressure and is measured in millimeters of mercury (mmHg), for example 140/90.
    • In the past, most attention was paid to diastolic pressure, but now we know that both high systolic pressure and high pulse pressure (the numerical difference between systolic and diastolic pressures) are also risk factors for disease.
    • In some cases, a decrease in excessive diastolic pressure can actually increase risk, probably due to the increased difference between systolic and diastolic pressures.
    • If systolic blood pressure is elevated (>140) with a normal diastolic blood pressure (<90), it is called "isolated systolic hypertension" and may present a health concern.

  • Cardiac Cycle

    • Every single heartbeat includes three major stages: atrial systole, ventricular systole, and complete cardiac diastole.
    • Complete cardiac diastole occurs after systole.
    • Thus, there are two types of measurable blood pressure: systolic during contraction and diastolic during relaxation.
    • Systolic blood pressure is always higher than diastolic blood pressure, generally presented as a ratio in which systolic blood pressure is over diastolic blood pressure.
    • For example, 115/75 mmHg would indicated a systolic blood pressure of 115 mmHg and a diastolic blood pressure or 75 mmHG.

  • Artery Function

    • Arteries are high-pressure blood vessels that carry oxygenated blood away from the heart to all other tissues and organs.
    • Arteries are blood vessels that carry blood away from the heart under pressure.
    • In arteries, the tunica media, which contains smooth muscle cells and elastic tissue, is thicker than that of veins so it can modulate vessel caliber and thus control and maintain blood pressure.
    • Arterial pressure varies between the peak pressure during heart contraction, called the systolic pressure, and the minimum or diastolic pressure between contractions, when the heart expands and refills.
    • This pressure variation within the artery produces the observable pulse that reflects heart activity.

  • Checking Circulation

    • For each heartbeat, blood pressure varies between systolic and diastolic pressures.
    • Diastolic pressure is minimum pressure in the arteries, which occurs near the beginning of the cardiac cycle when the ventricles are filled with blood.
    • An example of normal measured values for a resting, healthy adult human is 120 mmHg systolic and 80 mmHg diastolic.
    • The pressure at which this sound is first heard is the systolic blood pressure.
    • The cuff pressure is further released until no sound can be heard (fifth Korotkoff sound), at the diastolic arterial pressure.

  • Hypertension

    • Hypertension is elevated blood pressure, clinically defined as at or greater than 140/90 (systolic/diastolic) mm/Hg.
    • Hypertension (HTN) or high blood pressure, sometimes called arterial hypertension, is a chronic medical condition in which the blood pressure in the arteries is elevated.
    • Blood pressure involves two measurements, systolic and diastolic, which depend on whether the heart muscle is contracting (systole) or relaxed between beats (diastole).
    • Normal blood pressure at rest is within the range of 100-140mmHg systolic (top reading) and 60-90mmHg diastolic (bottom reading).
    • Persistant high blood pressure can affect many areas of the body.

  • Extremes in Blood Pressure

    • Chronically elevated blood pressure is called hypertension, while chronically low blood pressure is called hypotension.
    • In healthy adults, physiological blood pressure should fall between the range of 100-140 mmHg systolic and 60-90 mmHg diastolic.
    • Hypertension or high blood pressure, sometimes called arterial hypertension, is a chronic medical condition in which the blood pressure in the arteries is elevated above 140/90 mmHg.
    • Even moderate elevation of arterial blood pressure is associated with a shortened life expectancy.
    • However, blood pressure is considered too low only if noticeable symptoms are present.

  • Operation of Atrioventricular Valves

    • Valves open or close based on pressure differences across the valve.
    • The subvalvular apparatus has no effect on the opening and closing of the valves, which is caused entirely by the pressure gradient of blood across the valve as blood flows from high pressure to low pressure areas.
    • Atrial systole (contraction) increases the pressure in the atria, while ventricular diastole (relaxation) decreases the pressure in the ventricle, causing pressure-induced flow of blood across the valve.
    • Blood passes through the tricuspid valve the same as it does through the bicuspid valve, based on a pressure gradient from high pressure to low pressure during systole and diastole.
    • The reason that the valves have different numbers of leaflets is not fully understood, but may arise from differences in tissue structure and pressure that occur during fetal development.

  • Venous Blood Pressure

    • Venous pressure is the vascular pressure in a vein or the atria of the heart, and is much lower than arterial pressure.
    • Venous pressure is the vascular pressure in a vein or the atria of the heart.
    • Central venous pressure, a good approximation of right atrial pressure, which is a major determinant of right ventricular end diastolic volume.
    • Portal venous pressure or the blood pressure in the portal vein.
    • This ensures that end diastolic volumes are maintained and that the brain will receive adequate blood, preventing loss of consciousness.