Cardiac emergencies Flashcards
What is the primary function of the cardiac conduction system?
To generate electrical impulses that conduct rapidly to other cells of the heart (Known as conductivity)
This property is known as conductivity.
What are the 3 groups of conductive cells?
in pacemaker sites with automaticity (the ability to conduct impulses automatically). the locations are as follows: SA node, AV node, and purkinje fibers.
The SA node is known as the primary pacemaker of the heart.
What happens if the sinoatrial node fails?
The atrioventricular (AV) node generates an impulse and if this fails, the purkinje fibers generate an impulse but it will not maintain ventricular contraction as effectively.
The AV node is a secondary pacemaker site.
What are Purkinje fibers responsible for?
Delivering the impulse to the working cells of the heart
They can initiate an impulse if both higher pacemaker sites fail.
What are working cells?
also called contractile cells. Their
primary purpose is to contract in response to the electrical impulses provided by the conduction system.
Conductive cells generate impulses, while contractile cells respond to them.
what is depolarization and repolarization?
Each heartbeat, or mechanical contraction of the
heart, has two distinct components of electrical activity: depolarization and repolarization. Depolarization is
the first, in which electrical charges of the heart muscle
change from negative to positive and cause heart muscle
contraction. Repolarization is the second component,
in which the electrical charges of the heart muscle return
to a resting negative charge and cause relaxation of the
heart muscle.
It can occur due to increased pressure in the pulmonary vessels.
Describe the P wave
This is the first waveform of the ECG and
represents the depolarization (contraction) of the atria.
From there, it is pumped into the left ventricle.
Describe the QRS complex
This is the second waveform and represents the depolarization (contraction) of the ventricles and the main contraction of the heart.
This is necessary due to the high pressure in the aorta.
Describe the T wave
This is the third waveform and represents
the repolarization (relaxation) of the ventricles.
This is caused by pressure buildup in the left atrium and pulmonary veins.
What is the PR interval?
It represents the time it takes the heart’s electrical impulse to travel from the atria to the ventricles.
It provides a graphic representation of depolarization and repolarization.
The degeneration of the electrical conduction system.
the electrical conduction system
can be damaged or disturbed and cause the improper
functioning of the heart. Sometimes, these conditions produce an irritability of the heart that causes the
uncoordinated firing of electrical ventricular impulses
called premature ventricular complexes (PVC). When
PVCs occur in succession, they can produce ventricular tachycardia (V-Tach), which displays on an ECG as
steep peaks and valleys that are close together. If left
untreated, ventricular tachycardia can degenerate into
ventricular fibrillation (VF or V-Fib), which shows up as
smaller, uneven, disorganized peaks and valleys.
Each component represents different phases of electrical activity in the heart.
Blood flow of the heart
- inferior and superior vena cava
- right atrium
- tricuspid valve
- right ventricle
- pulmonary valve
- pulmonary arteries
- lungs dispose of CO2 & pick up O2
- pulmonary veins
- left atrium
- mitral valve
- Left ventricle
- aortic valve
- Aorta
- Blood goes to the rest of the body
It is measured from the beginning of the P wave to the beginning of the QRS complex.
Why does classic agina occur?
typically occurs upon an
increased workload placed on the heart. This can be
from an increase in the heart rate or contractile function.
What does unstable agina usually indicate
angina discomfort that is prolonged and
worsening or that occurs without exertion and when the
patient is at rest.
Patho of Agina Pectoris
Angina pectoris is a symptom
of inadequate oxygen supply to the heart muscle, or
myocardium. As noted earlier, it typically results from a decrease in oxygen delivered to the myo-
cardium, which is often caused by partial blockage of the
coronary arteries, which causes ischemia (reduced deliv-
ery of oxygenated blood) that results in tissue hypoxia
(oxygen deficiency in the tissues). Angina can also occur
from a dramatic increase in demand on the heart such as
from a cocaine-induced myocardial infarction. The lack
of oxygen causes the discomfort, sometimes described as “crushing,” or “squeezing,” or as a “tightness” by the
patient
Where is the pain of Agina usually felt?
The pain is usually felt under the sternum and can radiate to the jaw, down either arm, to the
back, or to the epigastrium (upper-center region of the
abdomen). The pain usually lasts for approximately 2–15
minutes. Many patients can tell you that they have had
angina as part of their past medical history and have
nitroglycerin prescribed for this condition. Prompt relief
of the symptoms after rest and administered nitroglycerin
is typical of angina.
What are common symptoms of angina pectoris?
• Steady discomfort, usually located in the center of the
chest but can be more diffuse throughout the front of
the chest
• Discomfort that is usually described as pressure, tight-
ness, aching, crushing, or heavy
• Discomfort that might radiate to the shoulders, arms,
neck, jaw, back, or epigastric region (upper center
abdomen)
• Cool, clammy skin
• Anxiety
• Dyspnea (shortness of breath)
• Diaphoresis (excessive sweating)
• Nausea and vomiting
• Complaint of indigestion pain
Symptoms can vary, especially in women, diabetics, and the elderly.
What should be done if classic angina is not relieved after three nitroglycerin tablets and rest?
Recognize it as an acute coronary syndrome emergency and provide prompt treatment
This indicates a potentially serious condition.
Characteristics of unstable angina
pain
or discomfort that occurs at rest, continues without relief,
or is prolonged. If the patient experiences angina that
occurs at rest and lasts for more than 20 minutes, angina
with a recent onset that progressively worsens, or angina
that wakes the patient at night (nocturnal angina), you
should view it as an acute coronary syndrome emer-
gency and provide prompt treatment and transport.
Emergency medical care angina pectoris
You should establish an
open airway. If the patient’s respirations become inad-
equate, begin positive pressure ventilation. Apply the
pulse oximeter, if available, to monitor the oxygen level.
Administer supplemental oxygen if the patient is dys-
pneic, hypoxemic, has obvious signs of heart failure, has
an SpO2 of 694%, or the SpO2 is unknown. Initiate oxy-
gen therapy via a nasal cannula at 2 lpm and titrate the
concentration and liter flow to achieve and maintain an
SpO2 of 94% or greater.
What should you do if a patient has prescribed nitroglycerin and a systolic blood pressure greater than 90 mmHg?
Place him in a sitting or lying position and administer nitroglycerin tablets or spray
What is the recommended aspirin dosage for suspected coronary artery occlusion?
160–325 mg
What is an acute myocardial infarction (AMI)?
When a portion of the heart muscle dies due to lack of oxygenated blood
Patho of AMI
An acute myocardial infarction
typically is the result of coronary artery disease that
causes severe narrowing or complete blockage of the
coronary arteries. A plaque erosion or rupture within
the coronary artery can cause the narrowing and block-
age to occur. The result is a portion of heart muscle
that does not receive an adequate supply of oxygenated
blood. After approximately 20–30 minutes without ade-
quate perfusion, the heart muscle begins to die. When the blood flow is blocked, the heart muscle
becomes ischemic (hypoxic from inadequate oxygen-
ation). If the blood flow is not restored to that portion of
heart muscle, the cells begin to die.
What are common dysrhythmias that can occur during a heart attack?
Ventricular fibrillation and ventricular tachycardia
How can you re-establish
blood flow in the coronary artery?
fibrinolytic agents, commonly referred to as “clot busters,”
it might be possible to dissolve the clot, reopen the coro-
nary artery, and restore perfusion to the ischemic heart
muscle.
How does chest discomfort from an AMI differ from angina?
AMI discomfort lasts longer and is usually not relieved by nitroglycerin
List some signs and symptoms of an acute myocardial infarction.
• Chest discomfort radiating to jaw, arms, shoulders,
or back
• Anxiety
• Dyspnea
• Sense of impending doom
• Diaphoresis
• Nausea and vomiting
• Light-headedness or dizziness
• Weakness
Which populations are more prone to atypical presentations of heart attack symptoms?
Diabetics, the elderly, and women
What is an silent MI
no chest discomfort is experienced. They might complain only of shortness of
breath, nausea, light-headedness, or weakness.
Emergency medical care for a suspected AMI?
Ensure a patent airway and provide positive pres-
sure ventilation with oxygen connected to the device if
the breathing is inadequate. If the respiratory rate and
tidal volume are both adequate, consider supplemental
oxygen. Administer supplemental oxygen if the patient
is dyspneic, is hypoxemic, has obvious signs of heart
failure, has an SpO2 of 694%, or the SpO2 is unknown.
Initiate oxygen therapy via nasal cannula and titrate the
concentration and liter flow to achieve and maintain an
SpO2 of 94% or greater. Place the patient in a position of comfort. If the
patient has a prescription for nitroglycerin, adminis-
ter one tablet every 3–5 minutes up to a total of three
tablets. Follow your local protocol. Be sure the systolic
blood pressure is above 90 mmHg and remains above
90 mmHg following each nitroglycerin administration. If
local protocol allows, administer 160–325 mg of aspirin.
Patho of Aortic Aneurysm
when a weakened section
of the aortic wall, usually resulting from atherosclero-
sis, begins to dilate or balloon outward from the pres-
sure exerted by the blood flowing through the vessel.
An aneurysm can exist for a long time with no symp-
toms or signs that the patient is aware of and then sud-
denly rupture, causing rapid and fatal internal bleeding
(Figure 17-10 ■). Aortic aneurysms occur most often in
the abdominal region. Pain can be felt, especially in the
back, when the aneurysm gets large enough, perhaps
shortly before rupture occurs. Usually, the aorta can-
not be felt with a physical examination, but at this final
stage it can be felt as a pulsating mass in the abdomen,
although this can be difficult or impossible to detect in
a heavy-set patient.
Patho of aortic dissection
there is a tear in the
inner lining of the aorta and blood enters the opening
and causes separation of the layers of the aortic wall. Aortic dissections occur most often in the thorax. The pain is classically most severe when the
dissection first occurs and is most often described as a
“sharp” pain, or sometimes as a “tearing” or “ripping”
pain, often felt in the back, flank, or arm. Syncope might
be the only sign in some patients. Depending on the
location of the dissection along the aorta, it can cause
symptoms similar to a stroke or to a myocardial infarction
and can lead to a myocardial infarction or other damage
to the heart. A difference of 20 mmHg or greater in the
systolic blood pressure reading between the upper arms
or a severe decrease or difference in the upper and lower
extremity pulse amplitude as compared to central pulses
in a patient complaining of back or sharp chest pain
should cause you to suspect a possible aortic dissection.
What should be done if aortic aneurysm is suspected?
Administer oxygen and transport the patient immediately
What is an aortic aneurysm?
A weakened section of the aortic wall that dilates or balloons outward
What characterizes aortic dissection?
A tear in the inner lining of the aorta causing separation of the layers
What type of pain is typically associated with aortic dissection?
Sharp, tearing, or ripping pain
How to treat AA?
If a pulsating mass is felt and aortic aneurysm is
suspected, administer oxygen and transport the patient
immediately because only surgery can prevent or repair
a rupture of the aneurysm. For a chest or back pain
that can result from an aortic dissection or that can be
a symptom of myocardial infarction, administer oxygen
and assist the patient with prescribed nitroglycerin if
the blood pressure is more than 90 mmHg and no signs
of hypovolemia are present. If aortic dissection is sus-
pected, do not administer aspirin.
What causes heart failure?
Inadequate ejection of blood from the ventricle
Patho of left heart failure
Left ventricular failure occurs when the left ventricle
cannot pump blood out of the left ventricle effectively
(Figure 17-12 ■). This reduces blood flow to the arteries
and the perfusion of blood to the cells throughout the
body. Furthermore, blood waiting to enter the left ventri-
cle from the left atrium and blood waiting to enter the left
atrium from the lungs backs up in a sort of “traffic jam.”
When the left ventricle fails to eject the normal amount of
blood with each contraction, the blood pressure begins
to build up in the left atrium. The increase in pressure in
the left atrium causes an increase in pressure in the pul-
monary veins, which are responsible for delivering blood
from the lungs to the heart. The increase in pressure in
the pulmonary veins creates a higher pressure in the cap-
illaries in the lungs. Remember that the capillaries in the
lungs are the sites of gas exchange with the alveoli. When
the pressure in the capillaries increases, fluid begins to
leak out between the capillary and the alveoli. The fluid
collects between the capillary and around the alveoli and
distal bronchioles. This causes the space between the
capillary and the alveoli to widen, making gas exchange
more difficult. The poor gas exchange leads to hypoxia.
This condition is referred to as pulmonary edema.
Patho of right heart failure?
When the right side of the heart fails, the blood backs
up into the venous system. The right side of the heart
can fail due to failure of the left ventricle. It can also fail
because of cardiac valve disease or an increase in pulmo-
nary vessel pressure (pulmonary hypertension). Chronic
obstructive pulmonary disease (COPD) can increase the
pressure in the pulmonary vessels in the lungs and cause
the right ventricle to work much harder. Over time, this
can cause the right ventricle to fail. Signs include periph-
eral edema, jugular vein distention, and liver enlargement.
What are common findings in left ventricular failure?
When the left ventricle fails, the cardiac output drops
and there is a diminishment in the perfusion pressure to
the rest of the body’s organs. Common findings include
a drop in systolic blood pressure (to include frank hypo-
tension), diminished or absent peripheral pulse ampli-
tude, altered mental status, changes in the heart rate,
poor urinary output, respiratory distress, inspiratory
rales, and possible pulmonary edema.
Findings within right ventricular failure
Remember that the right ventricle pumps blood to the
lungs for reoxygenation. If the right-sided cardiac output
starts to drop, the lungs may be hypoperfused, which can
lead to hypoxia and respiratory distress. Also, as the blood
starts to accumulate in the ventricle from poor ejection, it
eventually backs up into the atrium and subsequently into
the vena cava. Findings of this can include jugular venous
distension and peripheral edema. One other change in
normal physiology is that if the right side is pumping
inadequately, the left side of the heart receives an insuf-
ficient amount of blood. Because the left ventricle can
pump only as much blood as it receives, the patient might
also display many of the previously mentioned findings
of poor peripheral perfusion
What is CHF? patho
refers to the condition in which there is a
buildup of fluid (congestion) in the body resulting from
the pump failure of the heart. It represents the condition
in which the left, the right, or both ventricles are failing
to meet the body’s needs. It may be a chronic condition
that presents over a period, or it may be more acute,
Treatment for heart failure
patent airway. Provide positive pressure
ventilation with supplemental oxygen connected to the
device if the breathing is inadequate.
What is a common position heart failure patients assume to alleviate symptoms?
Upright position with legs, feet, arms, and hands dangling.
What are some signs and symptoms of heart failure?
- Marked or severe dyspnea
- Tachycardia
- Orthopnea
- Paroxysmal nocturnal dyspnea
- Fatigue on exertion
- Anxiety
- Tachypnea
- Diaphoresis
- Cool, clammy, pale skin
- Chest discomfort
- Cyanosis
- Agitation and restlessness
- Edema
- Crackles and wheezes
- Decreased SpO2 reading
- Blood pressure variations
- Jugular venous distention
- Distended abdomen
What to do if a heart failure patient experiences chest discomfort
If the patient has a
prescription for nitroglycerin, administer one tablet every 3–5 minutes to a total of three tablets. Follow your local
protocol. Nitroglycerin can be beneficial to the patient by
reducing the pressure in the arteries of the body, mak-
ing it easier for the left ventricle to pump the blood out.
Any venous dilation can cause less blood to return to the
heart and reduce the workload of the ventricles. Ensure
that the patient has a systolic blood pressure of greater
than 90 mmHg prior to administration of nitroglycerin.
What emergency care should be provided to a heart failure patient?
Ensure a patent airway and provide positive pressure ventilation with supplemental oxygen.
What is the initial oxygen administration for a dyspneic heart failure patient?
Via a nasal cannula starting at 2 lpm, titrate to maintain SpO2 of 94% or greater.
What is nitroglycerin used for in heart failure patients?
To reduce arterial pressure and decrease the workload on the heart.
Indications you should use nitroglycerin
The patient exhibits signs and symptoms of chest pain
or discomfort consistent with acute coronary syndrome.
The patient has physician-prescribed nitroglycerin or it
is carried on the EMS unit.
The EMT has received approval from medical direc-
tion, whether on-line or off-line, to administer the
medication.
What are contraindications for administering nitroglycerin?
The patient’s baseline systolic blood pressure is below
90 mmHg systolic or the systolic blood pressure has
decreased greater than 30 mmHg from the baseline.
The heart rate is less than 50 bpm or greater than
100 bpm.
The patient has a suspected head injury.
The patient is an infant or a child.
Three doses have already been taken by the patient.
The patient has taken tadalafil (Cialis) within the past
48 hours or vardenafil (Levitra) or sildenafil (Viagra)
within the past 24 hours.
What does nitroglycerin do?
Nitroglycerin dilates coronary arteries, peripheral arteries, and
veins, causing an increase in coronary artery blood flow, a
decrease in peripheral vascular resistance, and a decrease in
the myocardial workload
Side effects of nitroglycerin
The aim of administering nitroglycerin is to dilate blood
vessels in the heart, but blood vessels in other parts of
the body are dilated as well. This dilation can cause:
Headache
A drop in blood pressure
Changes in pulse rate as the body compensates for
the changes in blood vessel size
What are the indications for administering aspirin?
Chest pain suggestive of acute coronary syndrome and approval from medical direction.
Contraindications for aspirin?
Aspirin should not be given to a patient who is known to
be allergic (hypersensitive) to the drug.
Dosage of nitroglycerin?
The dosage of aspirin is 160–325 mg as soon as possible
after the onset of the chest discomfort and symptoms
of heart attack. It is recommended that 160–325 mg of a
nonenteric aspirin be chewed and swallowed.
Dosage of nitroglycerin
The dosage for EMT administration of nitroglycerin is
either one tablet or one spray under the tongue. The most
commonly prescribed dose is either 0.3 mg per tablet (or
metered spray), or 0.4 mg per tablet (or metered spray).
Regardless of the individual dose unit, the administered
dose may be repeated in 3–5 minutes if (1) the patient
experiences no relief; (2) the blood pressure remains
greater than 90 mmHg systolic or does not fall more than
30 mmHg below the baseline systolic pressure; (3) the
heart rate remains above 50 bpm and below 100 bpm;
and (4) medical direction gives authorization. The total
dose is three tablets or sprays, to include what the patient
took prior to your arrival.
What does Aspirin do?
Aspirin (acetylsalicylic acid [ASA]) is a medication that
produces a rapid antiplatelet effect. This effect decreases
the ability of platelets to clump together during the clot-
ting cascade and reduces the formation of a clot in the
coronary artery at the site of the blockage
Side effects of aspirin
The patient may experience stomach irritation
or heartburn, nausea, or vomiting
