Cardiovascular System: Anatomy, Disorders & Treatment - PDF

utcomes ​ Anatomy and Physiology of the Cardiovascular System ​ Blood flows through the heart's chambers in a specific sequence: right atrium, right ventricle, lungs, left atrium, left ventricle, and then to the body. ​ Blood circulates from the heart to the body a...

utcomes ​ Anatomy and Physiology of the Cardiovascular System ​ Blood flows through the heart's chambers in a specific sequence: right atrium, right ventricle, lungs, left atrium, left ventricle, and then to the body. ​ Blood circulates from the heart to the body and back to the heart, ensuring oxygen and nutrients are delivered to tissues and waste products are removed. ​ Acute Coronary Syndrome (ACS) ​ ACS encompasses conditions like unstable angina and myocardial infarction. ​ Recognize signs and symptoms such as chest pain, shortness of breath, and nausea. ​ Cardiac compromise refers to any condition that reduces the heart's ability to function effectively. ​ Management of ACS ​ Evaluate patient symptoms against ACS criteria. ​ Positioning: Keep the patient in a comfortable position, often sitting up. ​ Administer oxygen if the patient is hypoxic. ​ EMTs can administer medications like aspirin and nitroglycerin. ​ Criteria for immediate transport include severe symptoms and unstable vital signs. ​ Teamwork is crucial for effective intervention and transport. ​ Prehospital 12-lead ECGs can provide early diagnosis and treatment guidance. ​ Pathophysiology of Cardiac Conditions ​ Coronary artery disease can lead to angina pectoris and acute myocardial infarction (AMI). ​ Dysrhythmias are abnormal heart rhythms that can affect heart function. ​ Heart failure results from the heart's inability to pump effectively, leading to symptoms like edema and shortness of breath.  ​ An aneurysm is a weakened area in a blood vessel wall that can rupture. ​ Conditions like valve disorders and cardiomyopathies interfere with the heart's mechanical work. Key Terms ​ Cardiovascular disease is the leading cause of death in the United States, killing over half a million people annually. ​ Approximately 700,000 people in the U.S. are projected to have a heart attack each year, with a 15% mortality rate. ​ Over 85 million people in the U.S. live with the effects of cardiovascular disease. ​ EMS frequently encounters patients with cardiovascular disease, ranging from initial heart attack symptoms to cardiac arrest. ​ EMTs play a critical role as the entry point into the healthcare system for many cardiovascular patients. ​ Cardiovascular emergencies vary in severity, from simple to critical situations. Cardiac Anatomy and Physiology ​ The cardiovascular system consists of the heart, blood vessels, and blood, and is responsible for delivering oxygenated blood to the body's cells. ​ Blood is composed of red and white blood cells, platelets, and plasma. ​ Blood flows through the heart's chambers (atria and ventricles) and through arteries, veins, arterioles, venules, and capillaries. ​ The heart pumps blood through two main circulatory routes: pulmonary circulation (between the heart and lungs) and systemic circulation (between the heart and the rest of the body). ​ The heart generates and distributes its own electrical charge, which stimulates mechanical contractions to pump blood. ​ The cardiac conduction system passes electrical energy from cell to cell, causing the heart to contract rhythmically and continuously. ​ The heart muscle requires a constant supply of oxygen and nutrients, which it receives from the coronary arteries branching off the aorta.  ​ Any interruption in the heart's oxygen supply can lead to hypoxia and cell death, as the heart has no oxygen reserve. Acute Coronary Syndrome ​ Acute Coronary Syndrome (ACS): Refers to any condition where the blood supply to the heart is blocked or disrupted, leading to ischemia (lack of oxygenated blood) and potential cell death. ​ Causes of ACS: Can occur abruptly due to a clot in a coronary artery (heart attack) or gradually due to plaque buildup narrowing the artery. ​ Ischemia: A hypoxic condition where heart cells lack oxygenated blood, impairing their function and potentially leading to cell death if not corrected. ​ Symptoms of ACS: ​ Chest Discomfort: Often described as pain, pressure, squeezing, discomfort, or aching. Can radiate to the jaw, neck, arms, or upper abdomen. ​ Dyspnea: Shortness of breath, especially common in older patients and women. ​ Nausea/Vomiting: Frequently associated with ACS. ​ Syncope: Fainting or near fainting. ​ Generalized Weakness: Some patients, especially older adults, females, and diabetics, may not experience pain but report profound weakness. ​ Sweating: Sudden onset of sweating, sometimes mistaken for flu symptoms. ​ Abnormal Pulse/Blood Pressure: Pulse can be bradycardic (slower than 60 bpm), tachycardic (faster than 100 bpm), or irregular. Blood pressure can be hypotensive (systolic < 90) or hypertensive (systolic > 140 or diastolic > 90). ​ Palpitations: Irregular or rapid heartbeats felt as fluttering in the chest. ​ Anxiety: Patients may feel anxious, have a sense of impending doom, or display irritability and a short temper.  ​ Recognition and Treatment: Due to the varied symptoms, it is safer to treat all patients with potential ACS symptoms as though they are having a heart problem. Historical findings should not be solely relied upon to rule out ACS. Scan 20-2 Aspirin ​ Transportation of a patient with a heart condition must be conducted thoughtfully, calmly, and carefully. ​ Avoid rough rides with sudden starts, stops, and turns, as these can increase the patient's fear and stress, which can negatively impact the heart. ​ Speed is important to ensure the patient reaches the hospital quickly. ​ The use of sirens or horns should be judicious to avoid worsening the patient's condition. Cardiovascular Disorders ​ Heart problems can arise from disorders affecting blood vessels and heart function. ​ Most cardiovascular emergencies are due to changes in the inner walls of arteries, which can be part of the systemic, pulmonary, or coronary circulatory systems. ​ Issues with the heart's electrical and mechanical functions can also lead to cardiovascular emergencies. ​ Effective response to heart attacks requires teamwork from the scene to the hospital, including working with Advanced Life Support (ALS) and early hospital notification to improve patient recovery chances. Coronary Artery Disease ​ The heart muscle is perfused by the coronary arteries, which descend from the aorta and deliver oxygenated blood to the heart cells. ​ Coronary artery disease (CAD) occurs when these arteries are narrowed or blocked, reducing blood flow and oxygen delivery to the heart.  ​ CAD is a major health issue in the United States, causing hundreds of thousands of deaths annually. ​ The buildup of fatty deposits, or plaque, on the inner and middle walls of arteries causes CAD. Over time, calcium can deposit at the plaque site, hardening the area. ​ Non-modifiable risk factors for CAD include heredity and age. ​ Modifiable risk factors include hypertension, obesity, lack of exercise, high cholesterol and triglyceride levels, and smoking. ​ Modifiable risk factors can be managed through lifestyle changes such as quitting smoking, losing weight, and improving diet and exercise habits. ​ CAD itself is not typically an emergency, but its progression can lead to serious conditions that require immediate medical attention. Angina Pectoris ​ Angina pectoris refers to chest pain caused by coronary artery disease. ​ Coronary artery disease narrows the arteries that supply the heart, leading to reduced oxygen supply to the myocardium during exertion or stress. ​ Symptoms of angina pectoris include: ​ Chest discomfort or pain ​ Shortness of breath ​ Nausea ​ Sweating ​ Syncope (fainting) Figure 20-6 Angina pectoris, or chest pain, results when a coronary artery is partially blocked, depriving an area of the myocardium of oxygen during exertion. ​ Angina pectoris symptoms typically arise with stress or exertion and subside with rest, usually within 5 minutes. ​ Nitroglycerin is commonly prescribed for angina, indicating a history of the condition. It dilates blood vessels, primarily veins, reducing the heart's workload. ​ Nitroglycerin is available in various forms: sublingual tablets, sprays, and adhesive patches that release the medication gradually.  ​ Patients are generally advised to take up to three doses of nitroglycerin over 10 minutes for chest pain relief. If symptoms persist, they should seek medical help. ​ Angina is usually predictable, with exertion causing symptoms and rest alleviating them. However, as the condition progresses, symptoms may occur more frequently and with less exertion, making it harder to distinguish from a myocardial infarction. Assessing and Treating Angina Pectoris ​ Differentiating angina pectoris from acute myocardial infarction (AMI) is challenging because symptoms overlap significantly. ​ Patients with angina pectoris may exhibit symptoms such as discomfort, dyspnea, nausea, and syncope, similar to those of acute coronary syndrome (ACS). ​ A key differentiating factor is that symptoms of angina pectoris typically resolve with rest, whereas symptoms of myocardial infarction do not. ​ If symptoms subside completely before or shortly after EMS arrival, it suggests angina pectoris. ​ Despite this, any patient presenting with ACS symptoms should be treated as if they are experiencing a myocardial infarction until proven otherwise. ​ Treatment for symptomatic angina pectoris includes: ​ Administering oxygen ​ Giving nitroglycerin and aspirin ​ Obtaining a 12-lead ECG ​ Transporting the patient ​ If all symptoms have resolved, contact medical control to determine if further evaluation is necessary. Acute Myocardial Infarction ​ The narrowing of coronary arteries can lead to several cardiac conditions. ​ Plaque accumulation and hardening can create weak areas in the vessel, potentially causing an aneurysm.  ​ Narrowing of the vessel can lead to blood flow blockage by an occlusion. ​ Plaque accumulation narrows the inner diameter of the blood vessel and can make the inner lining hard and rough. ​ The rough surface inside the artery can facilitate blood clot formation, further narrowing the artery. ​ Clots and plaque debris form a thrombus, which can block blood flow and cause an occlusion. ​ A thrombus can break loose to become an embolism, potentially blocking blood flow in a smaller downstream artery. ​ Blockages can starve tissues of oxygen, leading to tissue death. ​ Blockages in large areas of the heart (heart attack) or brain (stroke) can be quickly fatal. ​ Acute myocardial infarction (AMI), or heart attack, occurs when a coronary artery is blocked by a thrombus or embolism, interrupting blood flow and causing myocardial cell death. ​ Rarely, blood flow interruption to the myocardium may be due to a ruptured coronary artery (aneurysm). Figure 20-7 (A) Cross-section of a myocardial infarction and (B) a heart with normal and infarcted tissue at lower left area. ​ Acute Myocardial Infarction (AMI) Complications: ​ Ischemia: Leads to cell injury and death, disrupting the heart's electrical function and causing abnormal conduction patterns. ​ Dysrhythmias: Abnormal electrical distribution in the heart, leading to harmful changes in rate, rhythm, and pumping ability. Can result in tachycardia, bradycardia, or ventricular fibrillation. ​ Mechanical Problems: Cell death from hypoxia can impair the heart's pumping action, potentially leading to cardiogenic shock, characterized by a dramatic drop in blood pressure. ​ Sudden Death: ​ Occurs within 2 hours of symptom onset, often outside hospitals.  ​ Nearly 25% of individuals have no prior history of cardiac problems. ​ Treatment Advances: ​ Fibrinolytics: Medications to dissolve clots in the coronary artery, most effective when administered early. ​ Balloon Angioplasty: Inserting a catheter with a balloon to reopen circulation. ​ Stents: Tiny pipes inserted within the artery to restore blood flow. ​ Post-AMI Care: ​ Aspirin: Taken daily to prevent another episode. ​ Beta Blockers: Medications that slow the heart and reduce its workload, improving patient outcomes. Assessment and Treatment of a Myocardial Infarction ​ Conduct a primary assessment to ensure the patient has a pulse and is breathing, as some acute myocardial infarction (AMI) patients may present in cardiac arrest. ​ Perform a secondary assessment to identify signs and symptoms of ischemia and an occluded coronary vessel, such as chest, jaw, neck, arm, and epigastrium discomfort, dyspnea, nausea, vomiting, syncope, and sweating. ​ Recognize that not all AMI patients will experience discomfort; some may only report fatigue or dyspnea on exertion. ​ Transport is the most important treatment for suspected myocardial infarction, as definitive interventions like fibrinolytics or angioplasty occur in the hospital. ​ Initiate transport immediately upon recognizing the pattern of acute coronary syndrome (ACS). ​ Many EMS systems have mechanisms to activate a system of care for AMI patients, emphasizing the time-sensitive nature of heart attacks. ​ Some hospitals are designated as cardiac centers specifically equipped to manage AMI patients.  ​ A 12-lead ECG is crucial for identifying specific electrical patterns associated with AMI and should be acquired and transmitted as soon as possible if protocols allow. ​ Contact Advanced Life Support (ALS) for suspected AMI patients, as advanced providers can interpret 12-lead ECGs and treat dangerous dysrhythmias. ​ Be prepared for cardiac arrest and consider bringing an automated external defibrillator (AED) into the patient's house. ​ Administer aspirin and nitroglycerin as detailed in previous sections. ​ Keep the AMI patient calm and consider deferring a lights-and-siren transport to reduce stress. ​ Do not allow suspected AMI patients to walk, as increased heart demand can worsen ischemia. ​ Follow local protocols and transport the patient to the most appropriate destination immediately. Heart Failure and Acute Pulmonary Edema ​ Heart failure is a progressive condition where the heart cannot pump blood efficiently, affecting one or both ventricles. ​ Difference from cardiac arrest: In heart failure, the heart continues to pump but inefficiently, whereas in cardiac arrest, the heart stops pumping entirely. ​ Consequences of inefficient pumping: ​ Impaired perfusion of body tissues, making simple tasks difficult. ​ Limited ability to compensate for challenges like blood loss. ​ Fluid backup causing dangerous breathing problems. ​ Right-sided heart failure: ​ Pressure builds in the right atrium and vena cava, leading to jugular venous distention (JVD). ​ Fluid leaks from capillaries, causing abdominal swelling and pedal edema. ​ Left-sided heart failure: ​ Pressure builds in the left atrium and pulmonary vein, leading to pulmonary edema.  ​ Fluid leaks into alveoli, impairing gas exchange and causing respiratory distress. ​ Pulmonary edema can be identified by crackles on lung auscultation. ​ Chronic vs. acute conditions: ​ Both right-sided and left-sided heart failure can be chronic. ​ Left-sided heart failure complications, like pulmonary edema, often develop abruptly after increased cardiac workload or new myocardial infarction. Assessment and Treatment of Heart Failure ​ Heart failure is not always an emergency; many live with it daily, requiring lifestyle changes. ​ It is often identified during secondary assessment, with patients typically having a history of heart failure and taking medications like beta blockers, ACE inhibitors, and diuretics. ​ Signs of chronic heart failure include fluid buildup, pedal edema, abdominal or buttock swelling, and jugular venous distention (JVD). ​ Patients often monitor their weight at home to track fluid status; significant weight gain can indicate worsening heart failure. ​ Acute heart failure, such as pulmonary edema, presents with difficulty breathing, crackles, and pink, frothy sputum. ​ Primary assessment of heart failure includes checking for inadequate breathing and using OPQRST and SAMPLE for patient history. ​ Detailed cardiovascular assessment should look for signs like crackles, JVD, and pedal edema, and vital signs should be assessed and reassessed. ​ Pulmonary edema can occur with various dysrhythmias and blood pressure levels. ​ Treatment focuses on acute presentations like pulmonary edema, requiring immediate ALS contact and possibly CPAP application. ​ CPAP helps by increasing airway pressures to open wet alveoli and improve oxygen exchange.  ​ Some EMS systems allow EMTs to administer nitroglycerin to dilate blood vessels and reduce heart workload; check local protocols. Aneurysm ​ Aneurysm is a cardiovascular disorder caused by weakened sections in arterial walls, which can be congenital or due to plaque buildup. ​ Common locations for aneurysms include arteries in the chest, abdomen, and brain. ​ Mechanism: A weakened artery area expands and dilates under normal blood flow pressure. Blood may break through the inner lining into the middle layers, further weakening the artery. ​ Rupture consequences: If a weakened artery section bursts, it can cause rapid, life-threatening internal bleeding and damage to tissues beyond the rupture due to lack of oxygenated blood. ​ Emergency sites: The most common emergency aneurysm sites are the aorta and the brain. ​ Brain aneurysm: When an artery in the brain ruptures, it causes a severe stroke, with severity depending on the rupture site and blood loss amount. Chapter Review ​ Patients with acute coronary syndrome (ACS) can present with a variety of symptoms, including chest pressure or pain, difficulty breathing, mild discomfort, or no chest discomfort at all. ​ A thorough secondary assessment is crucial to identify the signs and symptoms of ACS due to its varied presentations and potential severe complications. ​ Maintain a high index of suspicion and treat patients with ACS symptoms aggressively, as early treatment can be beneficial and is unlikely to cause harm. ​ Patients with suspected ACS who are hypoxic or short of breath require oxygen and prompt transportation to definitive care. ​ Assisting patients with their own nitroglycerin can help relieve pain and anxiety.  ​ Definitive treatment for acute myocardial infarction (AMI) occurs at the hospital; treat AMI as a time-sensitive disorder. ​ Consider appropriate transportation destinations, activate systems of care, and obtain an early 12-lead ECG if possible. ​ Aspirin and nitroglycerin are first-line medications for treating acute coronary syndrome. ​ Heart failure, a chronic condition, can have life-threatening acute presentations such as acute pulmonary edema, which should be recognized and treated aggressively. Chapter Glossary ​ Acute Coronary Syndrome (ACS): Represents symptoms related to lack of oxygen (ischemia) in the heart muscle; also known as cardiac compromise. ​ Acute Myocardial Infarction (AMI): Condition where a portion of the myocardium dies due to occlusion; commonly referred to as a heart attack. ​ Aneurysm: Dilation or ballooning of a weakened section of an artery wall. ​ Angina Pectoris: Chest pain occurring when blood supply to the heart is reduced, causing a portion of the heart muscle to receive insufficient oxygen. ​ Bradycardia: Slow heart rate, typically less than 60 beats per minute. ​ Cardiovascular System: Comprises the heart and blood vessels. ​ Coronary Artery Disease (CAD): Diseases affecting the arteries of the heart. ​ Dyspnea: Shortness of breath or labored breathing. ​ Dysrhythmia: Disturbance in heart rate and rhythm. ​ Embolism: Blockage of a vessel by a clot or foreign material transported by the blood. ​ Heart Failure (HF): Inability of the heart to pump efficiently, leading to excessive blood or fluids in the lungs, body, or both; previously known as congestive heart failure (CHF). ​ Nitroglycerin: Medication that dilates blood vessels. ​ Occlusion: Blockage of an artery by fatty deposits. ​ Pedal Edema: Accumulation of fluid in the feet or ankles.  ​ Pulmonary Edema: Accumulation of fluid in the lungs. ​ Tachycardia: Fast heart rate, typically more than 100 beats per minute. ​ Thrombus: Blood clot formed of blood and plaque attached to the inner wall of an artery or vein. Short Answer ​ For a patient with difficulty breathing and a blood pressure of 100/70, the best position is typically sitting upright to facilitate easier breathing. ​ For a patient with chest pain and a blood pressure of 180/90, the best position is usually sitting or semi-Fowler's position to reduce the workload on the heart. ​ Two contraindications for the administration of aspirin are: ​ Allergy to aspirin ​ Active gastrointestinal bleeding ​ Two contraindications for the administration of nitroglycerin to a patient with acute coronary syndrome are: ​ Hypotension (low blood pressure) ​ Use of phosphodiesterase inhibitors (e.g., sildenafil) within the last 24-48 hours ​ Three signs or symptoms associated with acute pulmonary edema are: ​ Shortness of breath ​ Pink, frothy sputum ​ Crackles or rales on auscultation Thinking and Linking ​ For a patient experiencing difficulty breathing, chest pressure, and high blood pressure (160/100), the best way to transfer her down a flight of stairs is to use a stair chair. This ensures safety and stability during the descent. ​ When a patient with chest pain radiating to the left shoulder refuses to go to the hospital despite understanding the risks, you must respect his decision if he is alert and has the capacity to make informed decisions. Document the refusal and ensure he understands the potential consequences. Critical Thinking Exercises ​ Early intervention is crucial for heart attack survival, significantly reducing mortality. ​ Prehospital 12-lead ECG plays a vital role in early diagnosis and treatment, allowing for quicker and more accurate medical response. ​ By-passing the closest hospital may be beneficial if another hospital offers more specialized care for acute myocardial infarction (MI), potentially improving patient outcomes. Pathophysiology to Practice ​ A 66-year-old male patient with excruciating central chest pain radiating to his back and a history of a "bubble" on a blood vessel in his chest is most likely describing an aortic aneurysm. ​ Risks and benefits of administering aspirin and nitroglycerin: ​ Aspirin: Risk of exacerbating bleeding if the aneurysm ruptures. ​ Nitroglycerin: Risk of lowering blood pressure, which could be dangerous if the aneurysm is unstable. ​ An elderly male patient with heart failure (HF) experiencing severe difficulty breathing, weight gain, and needing to sleep propped up on pillows is showing signs of fluid retention and worsening heart failure. ​ Signs and symptoms related to HF: ​ Severe difficulty breathing: Indicative of pulmonary congestion due to fluid buildup. ​ Weight gain and tight belt: Suggests fluid retention. ​ Needing to sleep propped up: Known as orthopnea, a common symptom of worsening heart failure.