Blood Pressure and Cardiac Cycle

Aortic pressure

Pressure in the aorta during cardiac cycle.

Atrial contraction / atrial systole

Pumps a small amount of additional blood into the ventricles.

Atrial depolarization

P wave

Atrial relaxation / atrial diastole

Would be after the P wave covered up by the QRS

Atrial pressure

Pressure in the atria during the cardiac cycle.

Atrial repolarization

occurs at same time as QRS complex

Cardiac cycle

Encompasses one complete heart beat. Has five phases.

Cardiac output

Amount of blood pumped into the aorta by the heart.

Dicrotic notch

Brief rise in aortic pressure caused by backflow of blood rebounding off semilunar valves

Electrocardiogram

record of the electrical activity of the heart

Heart rate

heart beats/minute

Heart sounds

Sounds produced by closing heart valves.

First heart sound

A low-frequency sound that occurs at the beginning of the cardiac cycle, when the atrioventricular (AV) valves (mitral and tricuspid) close.

S1 Lub

Second heart sound

the sound produced by the closure of the aortic and pulmonary (semilunar) valves at the end of ventricular systole (contraction).

Isovolumetric contraction

This starts ventricular systole, where pressure builds in the ventricles. Remember that the ventricles have filled with blood and this volume stretches the ventricular myocardium, which will help with contraction force. However, there is no movement of blood because all valves are closed.

Isovolumetric relaxation

This is the beginning of ventricular diastole. Pressure falls in the ventricles, but no blood moves because all the valves are closed. After this phase, the ventricular (passive) filling phase occurs again and the cycle continues.

Passive ventricular filling

The ventricular volume increases substantially during this phase, but the atria are in diastole, so it is occurring passively.

Phonocardiogram

a record of heart sounds

Stroke volume

The amount of blood pumped out by one ventricle during ventricular ejection.

Ventricular contraction / ventricular systole

Immediately follows the depolarization of the ventricles. Contraction begins at the apex of the heart, forcing blood into the main arteries leaving the ventricles.

Ventricular depolarization

QRS complex

Ventricular ejection

The semilunar valves open because ventricular pressure exceeds aortic pressure. Blood moves from the left ventricle to the aorta.

Ventricular filling

Phase of the cardiac cycle in which the ventricles expand, their pressure drops, and the AV valves open and blood flows into the ventricles

Ventricular pressure

Pressure within the ventricles during contraction.

Ventricular repolarization

T wave

Ventricular relaxation / ventricular diastole

The phase of the cardiac cycle when the ventricles (lower chambers of the heart) relax and fill with blood.

Ventricular volume

amount of blood pumped by one ventricle during a contraction

Blood pressure

Measured in millimeters of mercury (abbreviated mmHg), and is typically provided as a fraction with systolic blood pressure in the numerator and diastolic blood pressure in the denominator (example: 120/90 mmHg).

Auscultation

Listening with a stethoscope

Diastole

Relaxation

Diastolic blood pressure

The lowest pressure, associated with the relaxation of the ventricles.

Hypertension

high blood pressure

Hypotension

low blood pressure

Korotkoff sounds

The sounds of blood spurting through the partially collapsed artery.

When you hear sharp tapping sounds, make a note of the pressure they first occur, which is the systolic pressure.

Make a note of the pressure when you STOP hearing the sounds. This is the diastolic pressure and indicates that blood is flowing normally through the artery again.

Mean arterial pressure

The average pressure present in the arteries. You can calculate with the following equation:

diastolic pressure + 1/3 (systolic pressure - diastolic pressure)

or diastolic pressure + 1/3 (pulse pressure)

Determined by the amount of blood pumped into the aorta by the heart (cardiac output, CO) and the amount of resistance that blood encounters as it flows, which is called total peripheral resistance (TPR)

MAP = CO x TPR

Pulse pressure

The difference in pressure between the systolic and diastolic pressures.

Sphygmomanometer

instrument to measure blood pressure

Stethoscope

instrument used for listening to internal body sounds

Systole

Contraction.

Systolic blood pressure

Peak pressure of the cardiac cycle

Total peripheral resistance

The amount of resistance that blood encounters as it flows

Pulse

Pulsations associated with the systolic and diastolic pressures through the skin

Brachial pulse

Place two or three fingers on the inner side of the upper arm, above the elbow crease.

Carotid pulse

Pulse felt on either side of the neck, over the carotid artery.

Facial pulse

At the angle of the mandible, where the facial artery crosses over the bone

Palpate

feeling for a pulse

Radial pulse

The pulse is located on the inside of the wrist (thumb side), where the radial artery runs just beneath the skin.

Ulnar pulse

Ulnar (pinky) side of the forearm at the wrist.

Anastomosis (pl. Anastomoses)

Where 2 blood vessels are joined together to create a pathway for blood flow. Ex: If either ulnar or radial arteries get blocked, anastomosis network allows blood to flow from remaining network, providing an alternate route.

Autonomic nervous system

The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.

Parasympathetic nervous system

The division of the autonomic nervous system that calms the body, conserving its energy

Sympathetic nervous system

The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.

Mean Arterial Pressure (MAP) =

Diastolic Pressure + (1/3 X Pulse Pressure)

Pulse Pressure =

Systolic Pressure - Diastolic Pressure

Cardiac Output (CO) =

Heart Rate X Stroke Volume

MAP =

CO X Total Peripheral Resistance