Defibrillation Course Cross Section of the Heart

Defibrillation Course

Cross Section of the Heart.Cross Section of the Heart.

Flow of Blood Through The Heart

Heart Anatomy

LOCATION: retrosternal – behind the

sternum

SIZE AND SHAPE: Little bigger than the size of your fist

Base – top of the heart

Apex – Bottom of the heart

Organ Layers:Inside layer – endocardium (smooth

muscle that lines the chamber)

Middle layer – myocardium (thickest muscle layer)

Outside Layer – epicardium

Pericardium – Protective sac surrounding the heart, 30cc of pericardial fluid acts

as a lubricant and cushion.

Heart Chambers

ATRIAL – superior chambers (if you are superior you are at the top)

- Right collects blood from the vena cavas.

- Left collects oxygenated blood from the lungs.

VENTRICLES – inferior chambers- Right pumps blood to lungs (LOW

pressure)- Left pumps blood out to body

(HIGH pressure)

SEPTUM – wall that separates the two sides of the heart

The 4 Chambers of the HeartThe 4 Chambers of the Heart

Right Atrium

Right Ventricle

Left Atrium

Left Ventricle

Receives blood from veins;Receives blood from veins;pumps to right ventricle.pumps to right ventricle.

Receives blood from lungs;Receives blood from lungs;pumps to left ventricle.pumps to left ventricle.

Pumps blood to the lungs.Pumps blood to the lungs. Pumps blood through the Pumps blood through the aorta to the bodyaorta to the body..

Heart ValvesFunction – to control blood flow through the heart.

Atrioventicular Valves(separate the atria & ventricles)

Tricuspid Valves (right side)

Mitral (Bicuspid) (left side)

Semilunar Valves

Pulmonic (right side)-between the right ventricle & pulmonary artery.

Aortic (left side)-between the left ventricle & the aorta.

Great VesselsLargest in the body to carry blood to and

from the heart.Vena Cava:

Superior – brings back blood from head and upper extremities

Inferior – brings back blood from area below the heart

Pulmonary Artery – carries deoxygenated blood to the lungs.

Pulmonary Vein – carries oxygenated blood back to the heart.

Aorta – carries oxygenated blood to the body.

Coronary Arteries2 main arteries

which sit on the surface of the heart; come off aortic arch.

IMPORTANCE – provides blood to the heart muscle itself (myocardium).

Flow of Blood Through The Heart

Oxygen LowConcentration

Vena CavaeRight Atrium(Tricuspid

Valve)Right Ventricle(Pulmonary

Valve)Pulmonary

Artery

L U N G S

Oxygen High ConcentrationPulmonary Vein

Left Atrium(Mitral Valve)Left Ventricle(Aortic Valve)Aorta

TO THE BODY

Blood Flow Through the Heart

It’s coloring time…

Pumping Action of the HeartStroke volume – the amount of blood ejected

from the ventricles with one contraction (60-100ml).

Cardiac Output – the amount of blood pumped through the circulatory system per minute.

FORMULA = heart rate x stroke volume

Normal Adult Heart Rate: 60-100 times per minute

What regulates the heart?

“Fight or Flight Response”

In response to the autonomic nervous system- Parasympathetic Nervous System

When activated, slows down the heart rate.

- Sympathetic Nervous System

Speeds up the heart rate.

Arteriosclerosis – hardening of the arteries

Atherosclerosis – fat and cholesterol deposits line the

vessels

Cardiac Assessment

What is the chief complaint?

1. Chest pain or discomfort – OPQRSTI

2. Previous episodes & history

3. Shoulder or neck pain

4. Dyspnea – worse with exertion?

5. Syncope

6. Palpitations

7. Past Medical History

Properties of the HeartAutomaticity

ability to beat on its own

Conductivityability to pass impulses from cell to cell

Contractibility

ability to receive an electrical impulse and contract

Excitabilityability to respond to an electrical stimulus

Rhythmiticitywhen stimulated, has rhythm

Depolarization:

When the heart contracts or pumps blood

Repolarization:

When the heart is resting and refilling

(RE=Rest)

What’s In a Heart Beat?

Electrocardiograph – Machine used to measure electrical heart activity.

Isoelectric Line – the black line on an ECG

Electrocardiogram – the read out or strip of paper showing the electrical activity.

ECG Placement - AED

Pacemakers of the Heart

• SA Node (sinoatrial) - Dominant pacemaker with an intrinsic rate of 60 - 100 beats/minute.

• AV Node (atrial ventricular) - Back-up pacemaker with an intrinsic rate of 40 - 60 beats/minute.

• Purkinje Fibers - Back-up pacemaker with an intrinsic rate of 20 - 40 bpm.

Cardiac Cardiac ConductionConductionSystemSystem

Cardiac Conduction & the ECG

SA node

AV node

Bundle of His

Bundle Branches

Purkinje fibers

What happens in a single heart beat??? - The “PQRST”

• P wave

– Atrial depolarization

– SA Node Fires

• T wave

-Ventricular Repolarization

• QRS - Ventricular depolarization- AV Node Fires

ATRIA RELAX BEFORE VENTRICLES CONTRACT

The PR Interval

Atrial depolarization

+

delay in AV junction

(AV node/Bundle of His)

(delay allows time for the atria to contract before the ventricles contract)

Types of AEDs

Biphasic

Sends shock in both directions, measures

resistance, and adjusts energy

Causes less damage to heart muscle

Monophasic

Sends single shock (energy current) from one pad to the other

Rationale for Early Defibrillation• Most frequent initial rhythm in sudden

cardiac arrest is ventricular fibrillation (VF)

• The only effective treatment for VF is defibrillation

• Probability of successful defibrillation decreases rapidly over time

Safety Considerations

Water

Dry patient’s chest; remove from wet environment.

Metal

Ensure no one is in contact with the patient and they are not touching any metal.

Additional SafetyConsiderations

Medication PatchIf patch is visible on the chest,

remove it with gloved hands before

delivering shock.

Safety Considerations

DO NOT defibrillate in a moving

ambulance – stop the vehicle to deliver the

shock. Road noise interferes in the

operation and it decreases the chance of

shocking another person

Use the proper pads: Adult pads for 8 and older and/or signs of puberty & Child Pads for 1 – 8 years old

Time is Critical• Immediately………….>95%

• 1 – 3 min……………..84%

• 4-6 min………………28 – 40%

• >10 min……………...<5%

Causes of Cardiac Arrest Other Than Heart Disease

• Drowning

• Trauma

• Electrocution

• Acid Base imbalance

• Electrolyte imbalance

• Drug toxicity

• Hypovolemia

• Hypoxia

Chain of Survival

Rhythms you NEED to know!!!

Ventricular Fibrillation - VF

Ventricular Tachycardia – VT

Asystole

Normal Sinus Rhythm

Pulseless Electrical Activity – PEA

Agonal – Dying Heart

Artifact

Premature Ventricular Contractions – PVC’s

Pacemaker

THE END

Not Shockable Rhythms

An AED will not shock:

Asystole (20-50% of victims) OR

Pulseless electrical activity (PEA) (15-20% of victims)

Typically only 6-7 out of 10 patients are in a shockable rhythm.

Safety Considerations

An AED must be applied ONLY to a patient who is unresponsive, apneic, and pulseless.

Say "Clear!" Ensure no one is touchingSay "Clear!" Ensure no one is touchingpatient. Press analyze button.patient. Press analyze button.

If AED advises shock, say "Clear," ensure If AED advises shock, say "Clear," ensure no one touching patient, and press shock no one touching patient, and press shock button. Repeat until up to 3 shocks are button. Repeat until up to 3 shocks are delivered.delivered.

Stacked Shocks

Key Term

Called stacked because after the first and second shocks in each set, pulse checks and CPR are not performed

After delivery of shock(s), check carotidAfter delivery of shock(s), check carotidpulse.pulse.

If there is no pulse, resume CPR for one If there is no pulse, resume CPR for one minute. Check effectiveness of CPR by minute. Check effectiveness of CPR by evaluating pulse.evaluating pulse.

Insert an airway adjunct and ventilate Insert an airway adjunct and ventilate with high-concentration oxygen.with high-concentration oxygen.

After one minute of CPR, clear patient After one minute of CPR, clear patient and repeat sequence of analyses and and repeat sequence of analyses and up to three additional shocks.up to three additional shocks.

If no shock is advised, check carotid If no shock is advised, check carotid pulse. If present, assess adequacy of pulse. If present, assess adequacy of breathing.breathing.

If breathing is adequate, give high-

concentration oxygen by nonrebreather.

If inadequate, ventilate with high-concentration oxygen.

If the AED gives 3 consecutive no-shock messages with no carotid pulse . . .

. . . or a total of six shocks are delivered . . . then transport with CPR and oxygen.

If advanced life support is not available, transport when:

Patient regains pulse, OR

You have delivered 6 shocks, OR

AED has given 3 consecutive no-shock messages

Do not touch patient when analyzing rhythm and delivering shocks.

Do not analyze rhythm or defibrillate in a moving ambulance. Stop first.

General AED Procedures

AED in Progress

If AED is in use by a first responder

when you arrive, ensure they are

performing properly, and continue

with shocks.

What happens in a single heart beat?

P wave - SA node fires - Depolarization of atria (contract)

QRS Complex - AV node fires- Depolarization of the ventricles. (contract)T Wave - Repolarization of the ventricles (rest and refill)

ATRIA RELAX BEFORE VENTRICLES CONTRACT