Cardiovascular Emergencies & Heart Failure

Cardiovascular Emergencies & Acute MI & Heart Failure

• Images of ECG are shown, indicating cardiovascular emergencies and acute MI, and heart failure.
• The study of cardiovascular emergencies is presented.

Cardiovascular System

• The cardiovascular system has the purpose of delivering oxygen, nutrients, hormones, and other protective components to the body cells.
• Pulmonary circulation is low pressure, which allows slow movement through the lungs for improved gas exchange.
• Systemic circulation is high pressure, which moves blood against gravity to allow for blood return to the heart from the body tissues.
• Deoxygenated blood returns to the heart from the body through the superior and inferior vena cava, then enters the right atrium.
• The deoxygenated blood moves through the tricuspid valve to the right ventricle.
• The right ventricle pumps deoxygenated blood, through the pulmonary artery to the lungs.
• The oxygenated blood in the lungs is transported through pulmonary veins to the left atrium.
• Through the mitral valve, the oxygenated blood goes to the left ventricle.
• The oxygenated blood is pumped through the aortic valve into the aorta, delivering oxygenated blood to the body.
• Deoxygenated blood returns to the heart via superior and inferior vena cava.
• A network of arteries and arterioles deliver the oxygenated blood to the organs and tissues.
• Waste products are collected from the tissues by the venules and veins.
• The blood returns to the heart as deoxygenated blood through the vena cava.

The Heart

• The layers of the heart are the pericardium, epicardium, myocardium, and endocardium.
• The pericardium is an outer sac with pericardial fluid that minimizes friction.
• The epicardium is an outer layer covering all vessels and folds to form the pericardium.
• The myocardium is the muscular layer that contracts.
• The endocardium is the inner layer lining the interior heart and valves.
• Systolic is the ventricular contraction.
• 70% of blood volume is the stroke volume (SV).
• Diastolic is the ventricular relaxation.
• The ventricles accept blood from the atria.

The Heart: Chambers & Valves

• The heart has four chambers: Right Atrium, Right Ventricle, Left Atrium, and Left Ventricle.
• The heart has four valves: Tricuspid, Pulmonary, Mitral (Bicuspid), and Aortic.
• Each valve has a unique function, to allow blood to flow in one direction.

The Heart: Blood Flow

• The heart has its own network of vessels called coronary arteries.
• The main coronary arteries are the left coronary artery and the right coronary artery.
• The left coronary artery branches into the left anterior descending artery and the left circumflex artery.
• The LAD artery supplies blood to the anterior part of the left ventricle and a portion of the interventricular septum.
• The right coronary artery supplies blood to the right atrium, right ventricle, and the inferior part of the left ventricle.
• During diastole, the resting phase of the cardiac cycle, the coronary arteries fill with oxygenated blood.

Coronary Perfusion Process

• During diastole, the coronary arteries receive blood flow.
• As the heart relaxes, the aortic valve closes, and the coronary arteries fill with oxygenated blood.
• Oxygenated blood, rich in nutrients, is delivered to the myocardium through small branches of the coronary arteries.

Coronary Artery Disease (CAD)

• Coronary perfusion can be compromised in conditions like CAD, where the coronary arteries may become narrowed or blocked by atherosclerotic plaques.
• Reduced blood flow leads to ischemia (lack of oxygen) and potential myocardial infarction (heart attack).

Cardiovascular System Nursing Assessment

• Inspection (for pallor or cyanosis, visible PMI), palpation (warm skin, capillary refill <2 seconds), palpate the abdominal and carotid pulses for symmetry).
• Auscultation (for S1 and S2 heart sounds, regular rate, rhythm, and absence of murmurs).
• Important subjective assessment questions include chest pain, discomfort, palpitations, shortness of breath.
• History of edema, symptom onset, aggravating/relieving factors Assess for other objective and subjective data as needed

Pericarditis

• Inflammation of the pericardium (sac surrounding the heart)
• Common Symptoms: chest tightness, increased pain with lying flat, sharp/stabbing pain that's relieved by sitting/leaning forward, muffled heart sounds.

Cardiac Tamponade

• Fluid accumulates in the pericardial sac, causing pressure on the heart and unable to completely fill.
• Symptoms: dyspnea, dizziness, chest tightness, increasing restlessness, pulsus paradoxus (>10mmHg drop in BP during inspiration).
• Nursing care includes monitoring for hypotension, tachycardia, muffled heart sounds and jugular vein distension.

Cardiac Biomarkers

• The cardiac biomarkers include troponin, CK-MB, and BNP.
• Troponin is a contractile protein released from the cardiac muscle during mismatch between oxygen demand and supply (ischemia).
• CK-MB is a cardiac enzyme that increases 3-6 hours post-injury and peaks at 12-24 hours.
• BNP is a hormone released by the ventricles. Measurement of these markers can help diagnose heart conditions, especially MI.

Myocardial Infarction

• Prolonged ischemia leads to irreversible damage (cell death).
• Blood flow obstruction.
• Myocardial oxygen demand exceeds supply.
• Risk factors include cigarette smoking, diabetes, hypercholesterolemia, and metabolic syndrome.
• Possible complications include arrhythmias, heart failure, and thromboembolism.

Angina Pectoris

• Stable angina is the most common form, typically triggered by exertion or stress, relieved by rest or nitroglycerin.
• Unstable angina is more serious and unpredictable, occurring at rest or with minimal exertion.
• Variant angina (Prinzmetal's angina) is less common and caused by temporary spasm in coronary arteries.

Angina Pectoris : Blood Flow

• Coronary artery disease (CAD) is the primary cause of angina, caused by atherosclerosis resulting in buildup of plaque in coronary arteries.
• Risk factors include age, gender, smoking, high blood pressure, high cholesterol, and diabetes.

Acute Coronary Syndrome (ACS)

• Unstable angina, NSTEMI, and STEMI are three main conditions of ACS often caused by rupture/erosion in coronary artery leading to blood clot formation
• Risk factors include cigarette smoking, diabetes, hypercholesterolemia, and metabolic syndrome.
• Important diagnoses include unstable angina (not permanent damage); STEMI (ST-segment elevation MI – significant damage to heart muscle); NSTEMI (non ST-elevation MI – partial blockage).

Electrical Activity of the Heart

• The heart's electrical system coordinates the contractions of the atria and ventricles.
• The electrical impulses originate in the sinoatrial (SA) node.
• The impulses travel through specialized pathways (intermodal pathways) to the atrioventricular (AV) node, and then to the bundle of His, bundle branches, and Purkinje fibers.
• The electrical activity is represented on an electrocardiogram (ECG). Key features include the P wave, PR interval, QRS complex, and ST segment.
• The different phases of the action potential include 0,1,2,3,and 4

Heart Sounds

• Auscultation of heart sounds (S1 and S2) and murmurs.
• Assessment: Location of auscultation, and significance of sounds based on rhythmicity, intensity, pitch, quality, and timing
• S1 = "lub": Closure of AV valves(mitral and tricuspid) during ventricular systole
• S2 = "dub": Closure of semilunar valves(aortic and pulmonary)

Electrocardiogram (EKG)

• The EKG is a graphical representation of the electrical activity of the heart.
• The EKG traces the electrical activity through different leads that provides information on the heart's electrical health.
• Essential waveforms on EKG include P wave, PR interval, QRS complex, ST segment, and T wave.
• Standard interpretations, abnormalities, and analysis of EKG are critical for diagnosis and treatment of cardiovascular problems.

Arrhythmias

• Understanding various arrhythmias, such as atrial fibrillation (AFib), atrial flutter, premature ventricular contractions (PVCs), ventricular tachycardia (VTach), and ventricular fibrillation (VFib).
• Recognize the differences among these arrhythmias and their implications for clinical management.
• The different types of arrhythmias, mechanisms behind them, and the corresponding ECG appearance patterns.

Myocardial Infarction (MI) Complications

• Dysrhythmias are common complications, and cardiac monitoring and medication administration would be appropriate in this case.
• Assessing for signs of emboli such as shortness of breath, abnormal heart sounds or neurologic deficits to help with medication administration.
• Pericarditis (inflammation), Thromboembolism and postinfarction angina
• Ventricular rupture
• Cardiogenic shock

Heart Failure

• Causes due to primary (unknown) and/or secondary reasons (chronic disease).
• Understanding the pathophysiology of preload, afterload and cardiac contractility. Recognizing the common symptoms associated with heart failure, such as edema in peripheral extremities, shortness of breath, and fatigue
• Evaluation of the various compensatory mechanisms and the consequent clinical presentation.

Hypertension

• High blood pressure (BP).
• Causes of Hypertension.
• Risk factors of Hypertension.
• Presenting signs of Hypertension.
• Common complications of Hypertension.