Cardiovascular Emergencies - Basics & Pathophysiology Flashcards
Normal electrical impulses in the heart begin in the ___
Sinus node
Where is the sinus node?
Upper right part of the right atrium
What is the sinus node also known as?
Sinoatrial node (SA)
From the SA node, the electrical impulses ___
Travel across both atria, causing them to contract
Between the atria and the ventricles, the impulses ___
Cross a bridge of special electrical tissue
Special electrical tissue that bridge the atria and ventricles
Atrioventricular node (AV)
What happens to the electrical impulse at the AV node?
It is slowed for about one to two-tenths of a second to allow blood time to pass from the atria to the ventricles
After the impulses exit the AV node they ___
Spread throughout both ventricles via the bundle of His, the right and left bundle branches, and the Purkinje fibers, ultimately causing the muscle cells of the ventricles to contract
Special characteristic of cardiac muscles cells not found in any other type of muscle cells
Automaticity
Allows a cardiac muscle cell to contract spontaneously without a stimulus from a nerve source
Automaticity
If no impulse arrives, the other myocardial cells are capable of ___
Creating their own impulses and stimulating a contraction of the heart, although at a generally slower rate
The stimulus that originates in the SA node is controlled by ___
Impulses from the brain, which arrive by way of the autonomic nervous system
___ nervous system speeds up the heart, and the ___ nervous system slows it down
- Sympathetic
- Parasympathetic
How does the heart supply itself with more oxygen and nutrients during times of exertion?
Dilation of the coronary arteries
The coronary arteries start at ___
The first part of the aorta, just above the aortic valve
The right coronary artery supplies blood to the ___
Right atrium and right ventricle, and in most people, the inferior wall of the left ventricle
The left coronary artery supplies blood to the ___
Left atrium and left ventricle and divides into two major branches, just a short distance from the aorta
___ supply the head and brain with blood
Left and right carotid arteries
___ supply blood to the upper extremities
Left and right subclavian arteries
As the subclavian artery enters each arm, it becomes the ___
Brachial artery
Just below the elbow, the brachial artery ___
Divides into two major branches: the radial and ulnar arteries
Two major arteries branching from the ___ supply blood to the head and arms
Upper aorta
At the level of the umbilicus, the descending aorta ___
Divides into two main branches called the right and left iliac arteries
The iliac arteries supply blood to the ___
Groin, pelvis, and legs
As the iliac arteries enter the legs through the groin, they ___
Become the right and left femoral arteries
At the level of the knee, the femoral artery ___
Divides into the anterior and posterior tibial arteries and the perineal artery, supplying blood to the lower legs and feet
After blood travels through the arteries, it enters ___
Arterioles
Smallest branches of veins
Venules
Carries blood from the head and arms back to the right atrium
Superior vena cava
Carries blood from the abdomen, pelvis, and legs back to the right atrium
Inferior vena cava
The superior and inferior venae cavae join at the ___
Right atrium
The MAP is a good measure of ___
Perfusion
Three primary components of perfusion
- Well-functioning heart
- Adequate volume of blood
- Blood vessels must be properly constricted
Chest pain or discomfort that is related to the heart usually stems from a condition called ___
Ischemia
Decreased blood flow
Ischemia
Disease involving a decrease in blood flow to one or more portions of the heart muscle
Ischemic heart disease
Most often, low blood flow to heart tissue is caused by ___
Coronary artery atherosclerosis
A disorder in which calcium and fatty material called cholesterol build up and form a plaque inside the walls of blood vessels, obstructing flow and interfering with their ability to dilate or contract
Atherosclerosis
Eventually, atherosclerosis can cause ___
Complete occlusion of a coronary artery
Inside diameter of the artery
Lumen
The inner wall of the artery becomes ___ with atherosclerotic plaques
Rough and brittle
A blood clot that is floating though blood vessels until it reaches an area too narrow for it to pass, stopping and blocking blood flow at that point
Thromboembolism
If a blockage occurs in a coronary artery, a ___ will result
Acute myocardial infarction (AMI)
AMI
Acute myocardial infarction
Acute myocardial infarction
Heart attack
Death of tissue
Infarction
Heart stops pumping completely
Cardiac arrest
Major controllable risk factors for an AMI
- Cigarette smoking
- High BP
- Elevated cholesterol level
- Elevated blood glucose level
- Lack of exercise
- Obesity
Major risk factors of AMI that cannot be controlled
- Older age
- Family history of atherosclerotic coronary artery disease
- Race
- Ethnicity
- Male sex
Other lifestyle risk factors for AMI
- Stress
- Excessive alcohol
- Poor diet
A term used to describe a group of symptoms caused by myocardial ischemia
Acute coronary syndrome (ACS)
ACS
Acute coronary syndrome
Temporary reduced blood flow to the heart
Angina pectoris
Angina pectoris is treated like ___
ACS
What causes angina?
Can be the result of a spasm of an artery, but usually its a symptom of atherosclerotic coronary artery disease
Angina occurs when ___
The heart’s need for oxygen exceeds its supply, usually during periods of physical or emotional stress when the heart is working hard
Anginal pain is commonly described as ___
Crushing, squeezing, or “like somebody standing on my chest”, felt in the mid portion of the chest, under the sternum
Angina can radiate to ___
The jaw, the arms (frequently the left arm), the mid portion of the back, or the epigastrium
Upper-middle region of the abdomen
Epigastrium
Angina pain lasts ___
Usually 3 to 8 minutes, rarely longer than 15 minutes
Angina may be associated with ___
Shortness of breath, nausea, or sweating
Angina will usually disappear with ___
Rest, supplemental oxygen, and nitroglycerin
With angina, the electrical system ___
Can be compromised due to the diminished oxygen supply and put the person at risk for problems with cardiac rhythm
Angina that is characterized by pain or discomfort in the chest of coronary origin that occurs in the absence of a significant increase in myocardial oxygen demand
Unstable angina
Untreated unstable angina is associated with a ___
Very high risk of spontaneous AMI
Angina that is characterized by pain in the chest of coronary origin that occurs in response to exercise or some activity that increases the demand on the heart muscle beyond the heart’s capacity to increase its own blood flow
Stable angina
Heart muscle cells begin to die about ___ after blood flow is cut off
30 minutes
After about ___, as many as one half of the cells in the heart can be dead
2 hours
In most cases, after 4 to 6 hours, more than ___ of the heart cells will be dead
90%
How AMI is fixed
Opening the coronary artery with thrombolytic medications of angioplasty can prevent permanent damage if done within the first few hours after the onset of symptoms
Angioplasty
Mechanical clearing of the artery
Thrombolytic
Clot-busting
An AMI is most likely to occur in ___
The larger, thick-walled left ventricle
Why is an AMI most likely to occur in the left ventricle?
More blood and oxygen demand than the right ventricle
Signs and symptoms of AMI
- Sudden onset of weakness, nausea, and sweating without obvious cause
- Chest pain, discomfort, or pressure that is often crushing, squeezing and that does not change with each breath
- Pain, discomfort, or pressure in the lower jaw, arms, back, abdomen, or neck
- Irregular heartbeat and syncope
- Shortness of breath or dyspnea
- Nausea/vomiting
- Pink, frothy sputum (indicating possible pulmonary edema)
- Sudden death
Three ways pain from an AMI is different from the pain of angina
- It may or may not be caused by exertion, but can occur at any time, sometimes when a person is sitting quietly or sleeping
- It does not resolve in a few minutes, can last between 30 minutes to several hours
- It may or may not be relieved by rest or nitroglycerin
___, may not experience pain during any AMI, but ay have other common complaints associated with ischemia
Older patients, women, and those with diabetes
It is not uncommon for the only complaint with an AMI, especially in older patients and women, to be ___
Fatigue
AMI without the chest pain
Silent myocardial infarction
Physical findings of AMI (general appearance)
- Often appears frightened
- May be nausea, vomiting, and a cold sweat
- Skin is often pale or ashen gray
- Occasionally cyanosis
Physical findings of AMI (pulse)
- Generally rate increases
- Dysrhythmias are common
- May feel an irregularity or even slowing of the pulse
Damage to the inferior area of the heart often presents with ___
Bradycardia
Physical findings of AMI (BP)
- May fall
- Most will have a normal or even elevated BP
Physical findings of AMI (respiration)
- Usually normal unless the patient has CHF, in which case respirations may become rapid and labored with a higher chance of cyanosis and possibly frothy sputum
- Difficulty breathing is common even with a normal rate
Physical findings of AMI (mental status)
- Often experience confusion or agitation and sometimes experience an almost overwhelming feeling of impending doom
Three serious consequences of an AMI
- Sudden death
- Cardiogenic shock
- Congestive heart failure
Heart is twitching erratically, using energy without pumping any blood
Ventricular dysrhythmia, known as ventricular fibrillation (VF)
Most common dysrhythmias after AMI
Premature ventricular contractions, or extra beats in the damaged ventricle
Rapid beating of the heart, 100 BPM or more
Tachycardia
Unusually slow beating of the heart, 60 BPM or less
Bradycardia
Rapid heart rhythm, usually at a rate of 150 - 200 BPM. The electrical signal starts in the ventricle instead of the atrium
Ventricular tachycardia (VT)
Effect of VT
The rhythm does not allow time between beats for the left ventricle to fill with blood. The heart pumps less volume and BP may fall, or the pulse may be lost altogether
Disorganized, ineffective quivering of the ventricles
Ventricular fibrillation (VF)
Effect of VF
No blood is pumped and the patient becomes unconscious within seconds
To shock the heart with a specialized electrical current in an attempt to stop the chaotic, disorganized contraction of the myocardial cells and allow them to start again in a synchronized manner to restore normal rhythmic beat
Defibrillate
Chances of survival after cardiac arrest while CPR is being completed before application of the AED
Diminishes 7% to 10% each minute
If uncorrected, unstable VT or VF will eventually lead to ___
Asystole
The absence of all heart electrical activity
Asystole
Without CPR, systole may occur within ___
Minutes
Systole usually reflects a long period of ___
Ischemia
Cardiogenic shock is more commonly found after an AMI that affects the ___
Inferior and posterior regions of the left ventricle
Failure of the heart occurs when ___
Then ventricular myocardium is so profoundly damaged that it can no longer keep up with the return flow of blood from the atria
CHF
Congestive heart failure
CHF can occur at any time after a ____
Myocardial infarction
Treatment of cardiogenic shock
- Position comfortably
- Administer oxygen at a rate to keep oxygen saturation at 95% to 99%
- Assist ventilations as necessary
- Cover with blankets to preserve body heat
- Prompt transport to ED
Treatment of CHF
- Take vital signs and give oxygen by CPAP
- Allow to sit upright with legs down
- Reassure
- Gather medications
- Give nitroglycerin if the systolic BP is greater than 100 mm/Hg
- Prompt transport to ED
With left-sided heart failure, the lungs become ___
Congested with fluid
If the right side of the heart is damaged, fluid ___
Collects in the body, often showing up as swelling in the feet and legs
The collection of fluid in the part of the body that is closest to the ground
Dependent edema
Chronic dependent edema may indicate ___ even in the absence of pain or other symptoms
Underlying heart disease
Any systolic BP greater than 130 mm/HG or diastolic BP greater than 80 mm/Hg
Hypertension
A systolic pressure greater than 180 mm/Hg in the presence of impending or progressive organ damage
Hypertensive emergency
Most common sign of a hypertensive emergency
Severe headache
Signs and symptoms of hypertensive emergency
- Severe headache
- Strong bounding pulse
- Ringing in the ears
- Nausea
- Vomiting
- Dizziness
- Warm skin (dry or moist)
- Nosebleed
- Altered mental status
- Sudden development of pulmonary edema
Untreated hypertensive emergencies can lead to ___
A stroke or a dissecting aortic aneurysm
Treatment of hypertensive emergencies
- Make comfortable
- Monitor BP
- Keep head elevated
- Transport to ED
- Consider ALS support
Weakness in the wall of the aorta. The aorta dilates at the weakened area, making it susceptible to rupture
Aortic aneurysm
Occurs when the inner layers of the aorta become separated, allowing blood at high pressures to flow between the layers
Dissecting aneurysm
Primary cause of dissecting aortic aneurysms
Uncontrolled hypertension
AMI vs Dissecting aneurysm onset of pain
AMI: Gradual, with additional symptoms
DA: Abrupt, without additional symptoms
AMI vs Dissecting aneurysm quality of pain
AMI: Tightness or pressure
DA: Sharp or tearing
AMI vs Dissecting aneurysm severity of pain
AMI: Increases with time
DA: Maximal from onset
AMI vs Dissecting aneurysm timing of pain
AMI: May wax and wane
DA: Does not abate once it has started
AMI vs Dissecting aneurysm region/radiation
AMI: Substernal; back is rarely involved
DA: Back possibly involved, between the shoulder blades
AMI vs Dissecting aneurysm clinical signs
AMI: Peripheral pulses equal
DA: BP discrepancy between arms or decrease in a femoral or carotid pulse
