Heart Function & Coronary Disorders Ch. 16

Pathophysiology Exam 2

What is the primary function of the cardiovascular system?

To deliver oxygen and nutrients to tissues, remove carbon dioxide and metabolic wastes, transport hormones, regulate body temperature, and maintain tissue perfusion

What are the four chambers of the heart?

Right atrium, right ventricle, left atrium, left ventricle

Which side of the heart pumps deoxygenated blood?

The right side

Which side of the heart pumps oxygenated blood?

The left side

Which chamber receives deoxygenated blood from the body?

The right atrium

Which chamber pumps blood into the lungs?

The right ventricle

Which chamber receives oxygenated blood from the lungs?

The left atrium

Which chamber pumps oxygenated blood to the body?

The left ventricle

Which chamber has the thickest myocardium?

The left ventricle

Why is the left ventricular wall thicker then the right ventricular wall?

Because it must generate enough pressure to pump blood throughout the systemic circulation

What vessel carries deoxygenated blood into the right atrium?

The superior and inferior vena cava

Which artery carries deoxygenated blood to the lungs?

The pulmonary artery

Which veins carry oxygenated blood to the heart?

The pulmonary veins

Which vessel carries oxygenated blood from the left ventricle to the body?

The aorta

List the pathway of blood flow through the heart beginning with the vena cava

1. Vena cava

2. Right atrium

3. Tricuspid valve

4. Right ventricle

5. Pulmonary valve

6. Pulmonary artery

7. Lungs

8. Pulmonary veins

9. Left atrium

10. Mitral valve

11. Left ventricle

12. Aortic valve

    1. Aorta

What is pulmonary circulation?

Blood flow from the right side of the heart to the lungs and back to the left side of the heart

What is systemic circulation?

Blood flow from the left side of the heart to the body and back to the right side of the heart

What is the function of the coronary arteries?

To supply oxygenated blood to the myocardium

Why can’t the myocardium obtain enough oxygen directly from the blood inside the heart chambers?

Because the heart muscle is too thick for oxygen to diffuse adequately from the chamber blood

Which coronary artery supplies most of the anterior wall of the left ventricle?

The left anterior descending (LAD) artery

Which coronary artery supplies the right atrium, right ventricle, and often the SA and AV nodes?

The right coronary artery (RCA)

Which coronary artery commonly supplies the lateral wall of the left ventricle?

The left circumflex artery (LCX)

Which coronary artery is known as the “widow maker” when critically blocked?

The left anterior descending (LAD) artery

Why is the LAD artery called the “widow maker”?

Because blockage can cause a massive anterior myocardial infarction with a high risk of sudden death

What is the myocardium?

The muscular middle layer of the heart responsible for contraction

What is the endocardium?

The smooth inner lining of the heart chambers and valves

What is the pericardium?

The fibrous sac that surrounds and protects the heart

What is the function of pericardial fluid?

To reduce friction between the heart and the pericardial sac during cardiac contractions

What is cardiac output (CO)?

The amount of blood pumped by the heart each minuteH

How is cardiac output calculated?

Cardiac Output = Heart Rate X Stroke Volume (CO = HR X SV)

What is stroke volume?

The amount of blood pumped out of one ventricle with each heartbeat

What three factors influence stroke volume?

Preload, after load, and contractility

What is preload?

The amount of ventricular filling/stretch before contraction

What is after load?

The resistance the heart muscle must overcome to eject blood

What is contractility?

The ability of cardiac muscle fibers to contract and generate force

What increases cardiac contractility?

Sympathetic stimulation and increased calcium availability

What decreases cardiac contractility?

Myocardial infarction, heart failure, and damage to cardiac muscle

What is ejection fraction (EF)?

The percentage of blood pumped out of the ventricle with each contraction

What is considered a normal left ventricular ejection fraction?

Approximately 55-70%

What does a reduces ejection fraction indicate?

Decreased pumping ability, commonly seen in systolic heart failure

What is the cardiac conduction system?

The electrical pathway that controls heart rhythm and contraction

What is the heart’s natural pacemaker?

The sinoatrial (SA) node

Where is the SA node located?

In the right atrium near the opening of the superior vena cava

What is the normal function of the SA node?

It initiates electrical impulses that cause atrial contraction

What is the normal resting heart rate controlled by the SA node?

60-100 beats per minute

What is the function of the atrioventricular (AV) node?

It delays the electrical impulse so the ventricles have time to fill before contracting

What is the order of electrical conduction through the heart?

1. SA node

2. AV node

3. Bundle of His

4. Bundle branches

   1. Purkinje fibers

What do purkinje fibers do?

Spread electrical impulses through the ventricles to cause ventricular contraction

What is an electrocardiogram (ECG/EKG)?

A test that records the electrical activity of the heartW

What does the P wave represent on an ECG?

Atrial depolarization (atrial contraction)

What does the QRS complex represent on an ECG?

Ventricular depolarization (ventricular contraction)

What does the T wave represent on an ECG?

Ventricular depolarization (ventricular relaxation)

What is coronary artery disease (CAD)?

Narrowing or blockage of coronary arteries that reduces blood flow to the myocardium

What is the most common cause of coronary artery disease?

Atherosclerosis

What is atherosclerosis?

Buildup of fatty plaques inside arteries that narrows the vessel and decreased blood flow

What is the difference between stable and unstable angina?

Stable angina occurs predictably with exertion and improves with rest; unstable angina occurs unpredictably and may occur at rest

What causes angina pain?

Temporary myocardial ischemia caused by inadequate oxygen supply

What is the main difference between angina and myocardial infarction?

Angina causes temporary ischemia without permanent damage; MI causes irreversible myocardial death

What is ischemia?

Reduced blood flow and oxygen supply to tissue

What is the main cause of myocardial ischemia in coronary artery disease?

Narrowed coronary arteries that cannot deliver enough oxygen-rich blood to heart muscle

What is angina pectoris?

Chest pain caused by temporary myocardial ischemia due to inadequate oxygen supply to the heart muscle

What is the difference between stable and unstable angina?

Stable angina occurs predictably with exertion and improves with rest; unstable angina is new, worsening, or occurs at rest and may indicate an acute coronary syndrome

What causes angina pain?

An imbalance between myocardial oxygen supply and demand

What are common triggers of stable angina?

Physical exertion, emotional stress, cold temperatures, heavy meals

What are the classic symptoms of angina?

Chest pressure, squeezing, heaviness, or tightness that may radiate to the arm, jaw, neck, or back

How is angina pain typically described?

Pressure, squeezing, fullness, or heaviness rather than sharp painWha

What relieves stable angina?

Rest and nitroglycerin

How does nitroglycerin help angina?

It causes vasodilation, decreased cardiac workload, and improves coronary blood flow

What is acute coronary syndrome (ACS)?

A group of conditions caused by sudden decreased blood flow to the myocardium, including unstable angina and myocardial infarction

What is the main pathological event in myocardial infarction (MI)?

Death of myocardial tissue caused by prolonged ischemia

What is the most common cause of an MI?

Rupture of an atherosclerotic plaque causing thrombus formation and coronary artery blockage

What is the difference between ischemia and infarction?

Ischemia is reduced oxygen delivery; infarction is tissue death from prolonged oxygen deprivation

What are classic signs and symptoms of myocardial infarction?

Severe chest pressure, pain radiating to arm/back/jaw, shortness of breath, sweating, nausea, anxiety

What symptom may be th only sign of MI in older adults or people with diabetes?

Shortness of breath, fatigue, weakness, or no obvious chest pain

Why can women experience different MI symptoms?

They are more likely to have atypical symptoms such as fatigue, nausea, back pain, or shortness of breath

What cardiac marker is most commonly used to diagnose MI?

Troponin

Why is troponin important in MI diagnosis?

It is released when cardiac muscle cells are damaged and is highly specific for myocardial injury

What ECG change may occur with myocardial ischemia?

ST-segment depression or T-wave inversion

What ECG change is associated with STEMI?

ST-segment elevation

What is the first medication commonly given for suspected MI?

Aspirin

Why is aspirin given during MI?

It inhibits platelet aggregation and helps prevent the clot from growing

What is the purpose of oxygen therapy during MI?

To improve oxygen delivery if the patient is hypoxic

What is PCI?

Percutaneous coronary intervention used to open blocked coronary arteries with balloon angioplasty and stent placement

What is the preferred treatment for STEMI when available?

Rapid PCIWha

What are thrombolytics?

Medications that dissolve blood clots to restore blood flow

What is a major complication of MI?

Arrhythmias, heart failure, or cardiogenic shockWh

What is cardiogenic shock?

Severe heart pump failure causing inadequate tissue perfusionW

What are the signs of cardiogenic shock?

Hypotension, weak pulse, cool clammy skin, confusion, decreased urine output, shortness of breath

What is myocarditis?

Inflammation of the heart muscle (myocardium)

What is the most common cause of myocarditis?

Viral infection

What are common symptoms of myocarditis?

Chest pain, fatigue, shortness of breath, palpitations, fever, and symptoms of heart failure

How does myocarditis affect the heart?

It can weaken the myocardium and decrease the heart’s ability to pump blood

How is myocarditis commonly diagnosed?

ECG, cardiac enzymes (such as troponin), echocardiogram, cardiac MMRI, and sometimes biopsy

What is the treatment for myocarditis?

Treat the underlying cause, rest, manage heart failure symptoms, avoid strenuous activityW

What is pericarditis?

Inflammation of the pericardium, the sac surrounding the heart

What are common causes of pericarditis?

Viral infections, autoimmune disorders, kidney disease, trauma, and after myocardial infarction

What type of chest pain occurs with pericarditis?

Sharp, stabbing chest pain that worsens with deep breathing or lying flat

What position improves pericarditis pain?

Sitting up and leaning forward

What heart sound is associated with pericarditis?

Pericardial friction rub

What is a pericardial friction rub?

A scratchy sound caused by inflamed pericardial layers rubbing together