Heart Structures Flashcards
What is the function of the Right Atria?
Receives deoxygenated venous blood returning from the body
It is a low-pressure chamber.
What does the Left Atria receive?
Oxygenated blood from the lungs
What is the role of the Interatrial septum?
Separates the two atrias and contains the foramen ovale in fetal circulation
What is the function of the Right Ventricle?
Pumps deoxygenated blood to the right and left lungs
What does the Left Ventricle do?
Pumps oxygenated blood to the body
What is the Interventricular septum?
Separates the two ventricles
What are the atrio-ventricular valves on the right and left sides?
- Right side: Tricuspid valve (three flaps)
- Left side: Bicuspid or mitral valve (two flaps)
What is the purpose of the Semilunar Valves?
Prevent backflow of blood into the ventricles
Where is the Pulmonary semilunar valve located?
Between the right ventricle and lungs
What does the Aortic valve separate?
The left ventricle from the aorta
Fill in the blank: Oxygen poor blood drains to the Rt. Atria from the body via the _______.
Superior and Inferior Vena Cava
What happens after blood passes from the Right Atria?
It goes through the tricuspid valve to the Right Ventricle
What is the only artery that carries deoxygenated blood?
The Right and Left pulmonary arteries
What do the Right and Left pulmonary veins carry?
Oxygenated blood from the lungs
What is the purpose of the mitral valve?
Allows blood to flow from the Left Atria into the Left Ventricle
What occurs during the contraction of the Left Ventricle?
Blood is forced through the aortic semilunar valve into the aorta
True or False: Both atrias contract together and both ventricles contract together.
True
What leads to a P wave on the EKG?
Atrial contraction at the end of diastole
What is the role of the SA node?
It is the pacemaker of the heart, pacing 60-100 beats/min
What does the impulse from the SA node stimulate?
Contraction of the atria
Where is the AV node located?
In the inferior portion of the interatrial septum
What is the pacing rate of the AV node?
40-60 beats/min
What does the Bundle of His do?
Conducts impulses down both sides of the interventricular septum
What leads to ventricular contraction on an EKG?
Depolarization caused by stimulation of the Purkinje fibers
What does the P wave on an ECG indicate?
Atrial depolarization (contraction)
What does the QRS complex represent in an EKG?
Ventricular depolarization (contraction)
What does the T wave indicate?
Ventricular repolarization (ventricles returning to resting state)
What is the normal PR interval time?
< 0.20 seconds
This corresponds to 1 large box on EKG paper.
What is the normal QRS interval time?
< 0.12 seconds
This corresponds to 3 small boxes on EKG paper.
What does the cardiac output equation represent?
CARDIAC OUTPUT = STROKE VOLUME X HEART RATE
This equation indicates how much blood is pumped by the heart in a given time.
What is preload?
The amount of blood volume inside the ventricle leading to ventricular stretch prior to contraction
Preload affects the strength of the heart’s contraction.
What is stroke volume?
Amount of blood ejected with each heartbeat
Stroke volume is a key component in determining cardiac output.
How is heart rate defined?
How fast the heart beats, measured in beats per minute
Heart rate is a crucial factor in overall cardiovascular function.
What does resistance refer to in the cardiovascular system?
How far x diameter of the pipes or vessels
Resistance affects blood flow and pressure in the circulatory system.
What is afterload?
Resistance or pressure the ventricles must overcome to eject stroke volume
Afterload influences the workload on the heart.
What is Angina Pectoris?
Clinical syndrome of pain or pressure in the anterior chest due to myocardial ischemia
Often related to obstruction of major coronary arteries.
What factors can produce pain in Angina Pectoris?
- Physical exertion
- Exposure to cold
- Eating a heavy meal
- Increased stress
These factors can decrease blood supply to the heart or increase demand.
What are the characteristics of pain associated with Angina Pectoris?
- Varying severity from minor pressure to agonizing pain
- May radiate to neck, jaw, and shoulders
Pain tends to subside when the precipitating cause is removed or after medication.
True or False: Vasoconstriction leads to less workload for the heart.
False
Vasoconstriction increases workload and oxygen consumption of the myocardium.
Fill in the blank: The ST segment duration is ______.
0.04 seconds
This represents the time between ventricular depolarization and repolarization.
What happens to myocardial oxygen consumption (MVO2) during vasoconstriction?
It increases
This is due to increased blood pressure and heart workload.
What is the significance of the T Wave in an EKG?
Represents ventricular repolarization
T Wave abnormalities can indicate cardiac issues.
What is the RR interval in EKG terms?
Time between successive R waves
This interval is crucial for determining heart rate.
What does a U Wave represent in an EKG?
A small wave that may follow the T wave
The significance of the U wave is still being studied, but it may relate to repolarization.
What is Stable Angina?
Narrowing of the coronary arteries; pain is predictable and brought on by stress or exercise
Stable angina is often manageable with rest or medication.
What characterizes Unstable Angina?
Narrowing of the coronary arteries; pain is unpredictable and may occur at rest or with increased stress
Unstable angina is a medical emergency and requires immediate attention.
What is Prinzmetal Angina?
Vasospasm of the coronary arteries; pain is unpredictable, often occurring at rest or during sleep
The cause is unknown but may be linked to the sympathetic nervous system, calcium, or hormone changes.
What is the sequence of events from Ischemia to Infarction?
Ischemia → Injury → Infarction
This sequence describes the progression of cardiac tissue damage.
What ECG changes indicate Ischemia?
ST depression and/or T wave inversion
These changes reflect reduced blood flow to the heart muscle.
What ECG change indicates Injury?
ST elevation
ST elevation suggests acute injury to the heart muscle.
What characterizes an Infarct on an ECG?
Pathological Q wave (wide and deep)
This indicates irreversible damage to the heart muscle.
What is Myocardial Infarction?
Cardiac cell destruction/death due to reduced or complete loss of blood supply
This leads to the replacement of dead tissue with scar tissue, compromising heart function.
What happens to cardiac tissue after an Infarction?
It is replaced with scar tissue; the heart cannot contract or conduct electrical impulses
The infarcted area loses its functional capabilities.
How quickly can changes in ECG and lab values be seen after the onset of a Myocardial Infarction?
Within seconds
These changes are crucial for the diagnosis and management of the condition.
How long must cardiac cells be denied oxygen to incur permanent damage?
20 minutes
Timely intervention is critical to prevent irreversible damage.
What are common causes of Myocardial Infarction?
- Arteriosclerosis
- Occlusion from embolus or thrombus
These factors contribute to the reduction of blood supply to the heart.
What is a common characteristic of pain associated with myocardial infarction?
Radiating to the left shoulder and arm, may also be in the face, jaw, and middle of the back
Chest pain may feel heavy or crushing, and may not be painful but frightening.
What are some additional symptoms that may accompany myocardial infarction?
Nausea, vomiting, diaphoresis
Diabetics often exhibit non-classic signs and symptoms.
What is the typical pulse characteristic in a myocardial infarction?
Rapid, irregular, weak
How does cardiac output and blood pressure change during a myocardial infarction?
Initially increased due to sympathetic nervous stimulation, but will drop as damage continues
What can cause arrhythmias in myocardial infarction?
Oxygen deprived myocardial tissues
These can lead to life-threatening conditions such as ventricular tachycardia or fibrillation.
What is a common gastrointestinal response during a myocardial infarction?
Vasovagal stimulation causing nausea, pallor, and perspiration
What catecholamines are released during decreased renal perfusion?
Epinephrine and norepinephrine
This leads to increased heart rate, peripheral vasoconstriction, and elevated blood glucose levels.
Which lab results typically increase during myocardial infarction?
WBCs, sedimentation rates, temperature, and blood glucose
Blood glucose may remain elevated for weeks.
When does cardiac troponin T (cTnT) typically increase after myocardial injury?
3-6 hours, remains elevated for 14-21 days
When does cardiac troponin I (cTnI) increase and for how long does it remain elevated?
Increases at 7-14 hours, remains elevated for 5-7 days
What is the normal time frame for CK-MB to return to normal after an increase?
Normal within 72 hours
CK-MB elevates 4-6 hours after injury and peaks within 24 hours.
What does an increase in myoglobin indicate?
Myocardial infarction
Myoglobin increases earlier than CK.
When do LDH-1 and LDH-2 typically elevate after myocardial injury?
Elevates at 4 hours, peaks within 48 hours
When does SGOT (AST) usually elevate after myocardial injury?
Elevates days 2-4
What does cardiac nuclear scanning (thallium) reveal?
Underperfused areas leading to dyskinesia
What does echocardiographic study calculate?
Wall motion and ejection fractions
The ejection fraction should be 55% or greater.
What is the purpose of coronary angiography?
Determines patency of coronary blood vessels and identifies arteries amenable to PTCA or CABG
What is the primary issue in left-sided congestive heart failure?
Weakened left ventricle unable to pump oxygenated blood effectively
What are the consequences of left-sided heart failure?
Blood backs up in the left atrium, pulmonary veins, and lungs, leading to pulmonary edema
What are common characteristics of left-sided heart failure?
Cough, pink frothy sputum, shortness of breath, fatigue, tachycardia, anxiety, restlessness, crackles in the lungs
What characterizes right-sided heart failure?
Inability of the right ventricle to pump effectively, leading to congestion in the vena cava and peripheral tissues
What are common symptoms of right-sided heart failure?
Dependent edema, periorbital edema, weight gain, jugular venous distention, ascites, anorexia, nausea, weakness
What is left sided heart failure often a precursor to?
Right sided heart failure
Left sided heart failure can lead to decreased coronary perfusion due to reduced cardiac output.
What condition is characterized by the progressive narrowing and degeneration of arteries?
Peripheral Arterial Disease
Most often caused by atherosclerosis, leading to ischemia in extremities.
What are the key characteristics of Peripheral Arterial Disease?
- Intermittent claudication
- Reddish extremity when dependent
- Blanching upon elevation
- Loss of hair
- Presence of ulcers or gangrene
- Diminished or absent pulses
These characteristics are indicative of arterial insufficiency.
What are the 6 P’s of arterial insufficiency?
- Pulse (weak or absent)
- Pallor
- Pain
- Paresthesia
- Paralysis
- Poikothermia
These signs help assess arterial blood flow.
What is Deep Vein Thrombosis (DVT)?
A blood clot that forms in a vein in the systemic circulation, often in the legs
Commonly associated with prolonged immobility.
What are some risk factors for developing DVT?
- CHF
- MI
- Prolonged bed rest or traction
- Obesity
- Dehydration
- Venous insufficiency
- Surgery
- Leg trauma
- Pregnancy
- Advanced age
These factors increase the likelihood of clot formation.
What are the characteristics of DVT?
- May be asymptomatic
- Unilateral swelling of the extremity
- Warmth, redness, and swelling in the localized area
- Pain and tenderness at the clot site
- Positive Homan’s sign
Homan’s sign indicates pain when dorsiflexing the foot.
True or False: Clots in the legs can lead to pulmonary emboli or cerebrovascular accidents (CVA).
True
Clots can travel to the lungs or the brain, causing serious complications.
