heart rate measurement.pptx

7/27/2019 Heart Rate Measurement.pptx

1/15

Heart Rate Measurement

1


2/15

Heart Rate Phases

2


3/15

Heart Beat The heart generates its own electrical impulse

The cardiac electrical signal controls:

the number of electrical impulses ( heart rate)

It triggers the heart muscle to contract in the correct

sequence as it spreads across the heart

Lubb-dubb heart sounds are caused by closing of heart valves Valves of the heart close when heart contracts to prevent

blood from flowing back into the ventricles3


4/15

Heart Beat

Steps:

1. Atria relax, fill with blood Diastole

2. Atria pushes blood into ventricle3. Ventricles contract, pushing blood into arteries Systole

Increased pressure during systole causes AV valves to close

lubb sound Ventricles relax, pressure decreases, causes Semilunar valves

to close dubb sound 4


5/15

Heart Rate

It is a Speed of heartbeat

The number of heartbeats per unit of time

The heart rate is typically expressed as beats per minute(bpm).

The heart rate can vary according to the body's physical

needs, including the need to absorb oxygen and excrete

carbon dioxide.5


6/15

Average Heart Rate

The normal heart rate ranges from 60 100 bpm

6


7/15

It is below 60 bpm, refers to slow heart rate

- Bradycardia It is above 100 bpm, refers to fast heart rate

- Tachycardia

If Heart rate is not regular in a regular pattern, this is referred

as,

- Arrhythmia.

Activities that can provoke change include physical exercise,

sleep, illness, ingesting, and drugs. 7


8/15

Measurement

Heart rate is measured by finding the pulse of the heart.

This pulse rate can be found at any point on the body

where the artery's pulsation is transmitted to thesurface.

The radial artery is the easiest to use to check the heart

rate.

For emergency situations the most reliable arteries to

measure heart rate are carotid arteries.8


9/15

ECG

Electrical activity of the heart is measured using an

electrocardiograph:

Instrument that detects electrical activity of the heart

Electrocardiograph produces electrocardiogram (ECG or EKG)

Graphical record of heart rate and rhythm

A more precise method of determining pulse involves the useof an electrocardiograph, or ECG (also abbreviated EKG).

9


10/15

ECG

An ECG the heart rate is measured using the R wave to R

wave interval (RR interval).

Additionally pulse oximeters measure heart rate by pulsedetection.

10
http://en.wikipedia.org/wiki/File:ECG-RRinterval.svghttp://en.wikipedia.org/wiki/File:ECG-RRinterval.svg


11/15

Basal heart rate

The basal or resting heart rate (HR rest ) is measured while

the subject is relaxed but awake.

The typical resting heart rate in adults is 60 80 beats perminute (bpm) .

This is the firing rate of the heart Sinoatrial Node (SAN),

where are located the faster heart pacemaker cells

driving the self-generated rhythmic firing and

responsible for the cardiac muscle automaticity 11


12/15

Maximum heart rate

The most accurate way of measuring HR max is via a cardiacstress test.

In such a test, the subject exercises while being monitored by

an ECG. During the test, the intensity of exercise is periodically

increased through increasing speed or slope of the treadmill ,

continuing until certain changes in heart function are

detected in the ECG, at which point the subject is directed to

stop.12


13/15

Stethoscopes

Stethoscopes are used to transmit heart sounds from chest

wall to the human ear.

When the stethoscopes chest piece is firmly applied, low

frequencies are attenuated more then high frequencies.

the stethoscopes is in shape of a bell and it makes contact

with skin which serves as the diaphragm at the bell rim.

The diaphragm becomes taut with pressure, thereby low

frequencies are attenuated.13


14/15

AED (automated external defibrillator)

Machine that delivers electric shock to the heart to restart

the heart

Used when:

Heart contractions are not coordinated and muscles are quivering not

contracting (ventricular fibrillation)

Heart rate is abnormal (cardiac arrhythmia)

Heart rate is too fast (ventricular tachycardia)

Improves survival rates by up to 30% if delivered in the first

few minutes.14


15/15

heart rate measurement.pptx

Documents