cardiac monitoring skills

Cardiac Monitoring Skills

NRSG450 Module One

Goals

• Student Will Be Able To Discuss Cardiac Monitoring And Correctly Place Chest Leads.

• Student Will Be Able To Interpret A Rhythm Strip For Cardiac Rate,

Wave Morphology, Direction, Duration And Relationships To Other Waves.

• Student Will Recognize Normal From Abnormal Rhythms.

• Student Will Recognize Basic Sinus, Atrial, Junctional And Ventricular Rhythm Variations.

• Student Will Identify Lethal Rhythms.

Background of Electrical Flow of the Heart

www.guidant.com

Electricity stimulates the heart muscle to contract. It spreads through the heart sequentially changing the polarity of the cell’s interior from negative to positive

(depolarization). This causes contraction of the muscle. The internal cell positive polarity changes back to negative (repolarization) and the muscle relaxes. This process proceeds through cell-to-cell communication and high speed tracts in the atria and ventricles.

Anchoring the Information• Electricity stimulates the heart muscle to contract.

• The internal cell is Negatively charged at rest.

• Stimulating the change of the cell’s internal and external

polarity is called Depolarization.

• Depolarization produces Contraction of the muscle.

• Repolarization is the return of the internal cell negative polarity

and muscle Relaxation.

• Depolarization and repolarization occur Sequentially.

• These processes proceed through Cell-to-cell communication

and high speed tracts.

TAKE THE QUIZ ON THE NEXT SLIDE AND TEST YOUR KNOWLEDGE OF WHAT YOU HAVE JUST LEARNED.


Depolarization-repolarization involves the exchange movement of sodium and potassium across the cell wall with calcium modulation. This exchange sets the rate of the electrical spread. This process, including a rest period, is called the action potential curve.

Butler.cc.tut.fi

Action Potential Curve

Intracellular

Cell wall

Extracellular


• Each heart cell is able to start the depolarization process – automaticity.

• Excitability is term given to a cell responsiveness to a electric stimulus.

• The ability of a cell to transmit a stimulus to another cell is contractivity.

• Contractility is a measure of the cell’s ability to contract upon electrical stimulus.

• These processes are influenced by the autonomic nervous systems & medications.


• The sino-atrial (SA) node is usually the group of cells that trigger depolarization. This is why the SA node is known as the heart’s pacemaker.

• The SA node usually sets the heart’s rate at 60 – 100 beats per minute.

Anchoring the Information

• Depolarization and repolarization involves the exchange movement of Sodium and Potassium across the cell wall with calcium modulation.

• This exchange sets the Rate of the electrical spread and muscle Contraction.

Anchoring the Information

• Ability to start the depolarization process.

• Measure of cell’s ability to contract.

• Cell’s responsiveness to a electric stimulus.

• Ability of cell to transmit a stimulus to another cell.

• These processes are influenced by the autonomic nervous systems & medications

Automaticity

Autonomic nervous system

Conductivity

Contractility

Excitability


• The flowing electricity is summarized to give a general direction. This is called the vortex.

• The vortex is the electrical direction viewed on the monitor.

• Electrical flow toward a positive electrode gives a upward deflection. Flow away from the positive electrode gives a downward deflection. cc.stimula.edu

Lead II

+

-


• A straight line is called the isoelectric line. It is seen when no electrical flow is detected in the heart.

Reading the Electrical Flow of the Heart

The electrical activity of the heart is picked up be electrodes, travels through the wires to a heated stylus and transferred to specially designed EKG paper.


• EKG is recorded on graph paper traveling at 25mm per second

• The horizontal axis is time.– 1 small block=1mm=0.04 sec– 5 small blocks= 1 big block =

5mm = 0.2 sec– 5 big blocks = 1 second– 30 big blocks = 6 seconds

• The vertical axis is voltage.– 1 small block = .01 mv– 10 small blocks=2 big blocks

= 1 mv


• One heart beat or an electrical wave propagation

Depolarization wave

Heart muscle contraction

DRAG LABELS TO CORRECT LOCATION AND REBUILD

THE CHART

CLICK FORWARD BUTTON TOADVANCE TO NEXT SLIDE


• p wave = atrial depolarization• Accounts for the time electrical

stimulation moves across the atria.

• Duration 0.06 – 0.12 sec (2 small blocks> 4 small blocks)

• Located before QRS complex• Height 2-3 mm (0.2-0.3 mv)• Shape rounded & positive

(upright)

Suran Dutsan@ rutgers.edu


• PR interval involves the atrial and nodal depolarization

• Measure from beginning of p wave to the beginning of the QRS

• Duration 0.12 – 0.20 sec


• Ventricular depolarization is represented by the QRS complex

location

Location follows the PR interval.Duration 0.06 - 0.12 secondsAmplitude dependent on Lead (~5-30 mm)Configuration dependent on Lead Deflection usually a combination of negative and positive, varies with leads

Schwimmin


• ST segment from the end of the S wave to the beginning of T wave

• Usually isoelectric, • May be from -0.5 - +1 mm

from the isoelectric line


• T wave is ventricular repolarization

Location follows the s waveConfiguration is round & smooth (looks like a big p wave)Deflection is usually positive


• QT segment is measured from the beginning of the QRS complex to the end of the T wave.

• Duration is rate dependent

• Not routinely measured

Reading theElectrical Flow of the Heart

www.overboro.kctc.edu

cardiac monitoring skills

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