Concorde Career College, Portland ST120 Unit 2: The Heart Concorde Career College, Portland

The Heart Objectives: Evaluate the anatomic development of the heart Describe the basic anatomy of the heart, including coverings, wall, chambers, and valves Trace the flow of blood into, through, and out of the heart Evaluate myocardial infarction Describe the conduction system of the heart Describe basic cardiac dysrhythmias and electrocardiogram elements

The Heart: Part of the Cardiovascular System Cardiovascular (Circulatory) System Blood Heart Arteries Veins Capillaries

Cardiovascular System Cardiovascular Pertaining to the heart and blood vessels.

Cardiovascular System Heart the pump Peripheral vascular system arteries – carry blood AWAY from the heart Veins – carry blood TOWARD the heart capillaries – tiny webs that connect the arteries and veins peripherally; gas exchange takes place called internal respirations The lymphatic system also part of the circulatory system

Function of the Blood Circulatory System-- Simply→ Transportation Blood Transports Hormones Enzymes Oxygen Carbon dioxide Carries nutrients (from various organs) and oxygen (from the lungs) to the body’s cells for use, which creates waste The waste (includes carbon dioxide) is carried from the cells to the excretory organs. Example-Lungs expires carbon dioxide

Cardiovascular System The Heart

Cardiovascular System General Information Located in the mediastinum Slightly bigger than a fist Contracts approximately 72 times per minute 2/3 of the heart is located toward the left of the thoracic cavity

Cardiovascular System Function of the Heart Pump Systole (contraction) Diastole (relaxation)

Coverings of the Heart Pericardium – loose fitting sac that covers the entire heart Serous pericardium – inside the pericardium; composed of two layers Parietal layer- lines the inside of the pericardium Visceral layer- thin layer that covers the heart Pericardial cavity – space located between the Parietal layer and the Visceral layer; contains pericardial fluid to reduce friction

Pericardium

Heart Anatomy Epicardium is the outer layer of the heart wall Each chamber is lined by a thin layer of tissue called the endocardium The wall of each chamber is composed of cardiac muscle tissue called the myocardium Pericardium - Fibrous sac that encloses the heart. Epicardium - Thin, outermost layer of the heart wall (contiguous with the pericardium. Myocardium - Muscle of the heart. Endocardium lines the interior of the heart.

Cardiovascular System Chambers of the Heart Atria (receiving chambers) Ventricles (pumping chambers) Separated into right and left sides by the septum Right atrium - thin walled chamber that receives blood from the venae cavae (inferior and superior). Right ventricle - pumps deoxygenated blood from the right atrium to the lungs via the pulmonary arteries. Left atrium - receives oxygenated blood from the lungs via the pulmonary veins. Left ventricle - Chamber with the thickest wall that pumps oxygenated blood from the left atrium to all parts of the body.

HEART CHAMBERS UPPER CHAMBERS – RIGHT AND LEFT ATRIA which receives oxygen poor blood returning from lungs and body LOWER CHAMBERS – RIGHT AND LEFT VENTICLES moves oxygen rich blood into arteries 1414 14 14 14

Cardiovascular System Heart Valves Tricuspid (right atrioventricular) Bicuspid (mitral or left atrioventricular) Pulmonary (semilunar) Aortic (semilunar) Tricuspid (right atrioventricular) - Allows blood to flow from the right atrium to the right ventricle. Bicuspid (mitral or left atrioventricular) - Allows blood to flow from the left atrium to the left ventricle Pulmonary (semilunar) - Allows blood to flow from the right ventricle to the pulmonary artery (deoxygenated blood to the lungs) Aortic (semilunar) - Allows blood to flow from the left ventricle to the aorta.

HEART VALVES why do we need heart valves? To keep the blood flowing one direction The valve that separates the right atrium from the right ventricle is called the? TRICUSPID VALVE The valve that separates the left atrium from the left ventricle is called the? BICUSPID VALVE or MITRAL 1616 16 16

Heart Valves SL or semilunar valves located between the two ventricles and the arteries that carry the blood away from the heart 1717

Heart Valves Pulmonary semilunar valve is located at the beginning of the pulmonary artery that allows blood to flow from the right ventricle to the lungs Aortic semilunar valve is located at the beginning of the aorta and allows blood to flow out of the left ventricle into the aorta 1818

Cardiovascular System Chordae Tendineae Stabilize valve flaps to promote one way blood flow

Cardiovascular System Myocardial Blood Supply Right coronary artery Left coronary artery Circumflex artery Right marginal branch Anterior and posterior interventricular arteries

Coronary arteries and Coronary veins .

Blood Flow through the Heart The right side of the heart receives oxygen-poor blood from the veins Blood enters right atrium through the superior vena cava and the inferior vena cava 2222

Blood Flow through the Heart When the heart “beats”, first the atria contract simultaneously (atrial systole) 2323

Blood Flow through the Heart Then the ventricles fill with blood and they contract together When the ventricles contract, blood in the right ventricle is pumped through the pulmonary semilunar valve into the pulmonary artery and to the lungs, where it is oxygenated 2424

Blood Flow Through the Heart Oxygenated blood returns to the left atrium through 4 pulmonary veins It then passes through the left AV or bicuspid valve to the left ventricle Bicuspid = mitral 2525

Blood Flow Through the Heart From the left ventricle, the blood is pumped out through the aortic semilunar valve to the aorta From the aorta to the rest of the body! 2626

Conduction System Electrical impulses that signal the heart to beat All cardiac muscle fibers in each region of the heart are electrically linked together! Intercalated disks are electrical connectors that join the muscle fibers 2727

Cardiovascular System Conduction System Sinoatrial (SA) node Atrioventricular (AV) node Bundle of His Right and left bundle branches Purkinje fibers The vital control center in the medulla oblongata influences the heart rate and provides autonomic innervation (vagus nerve - X cranial) of the heart, but the heart beat itself is initiated within the heart. 1. The SA node generates the electrical impulse that begins the heartbeat. 2. The electrical impulse travels throughout the muscle of the atria causing contraction. 3. The AV node is stimulated. 4. The impulse travels through the bundle of His, the right and left bundle branches and the Purkinje fibers causing ventricular contraction.

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Cardiac Cycle Each complete heartbeat is called a cardiac cycle Consists of alternating systole (contraction) and diastole (relaxation) of atria and ventricles Stroke volume is the volume of blood ejected from the ventricles during each beat Cardiac output is the volume of blood ejected from the left ventricle into the aorta 3030

Pathology Coronary Atherosclerotic Heart Disease - a condition in which fatty material collects along the walls of arteries. This fatty material thickens, hardens (forms calcium deposits), and may eventually block the arteries; endothelial cell dysfunction Myocardial Ischemia - (reduced blood supply) of the heart muscle, usually due to the blockage caused by Coronary Atherosclerosis Angina pectoris – chest pain due to Myocardial Ischemia Myocardial Infarction (MI) – death of heart muscle tissue from Myocardial Ischemia, which leads to sudden cardiac death

Pathology Ventricular fibrillation – major dysrhythmia of the ventricles. They flutter without coordination which results in lack of blood pumped out of the heart Heart block – a disease in the electrical system of the heart Asystole – cardiac arrest Myocardial rupture – blood escaping the ventricles and entering the pericardial sac; can result in cardiac tamponade Cardiac aneurysm – ballooning of the ventricular wall resulting in increases pressure in the ventricles

Coronary Atherosclerotic Heart Disease Macrophage (big eater: type of monocyte) - Macrophages function in both non-specific defense (innate immunity) as well as help initiate specific defense mechanisms (adaptive immunity) of vertebrate animals. Their role is to phagocytose, or engulf and then digest, cellular debris and pathogens, either as stationary or as mobile cells. They also stimulate lymphocytes and other immune cells to respond to pathogens. They are specialized phagocytic cells that attack foreign substances, infectious microbes and cancer cells through destruction and ingestion.

Coronary Atherosclerotic Heart Disease Foam cell - Foam cells are a variety of macrophages, or immune system cells, that try to cope with excessive cholesterol. They are found in blood vessel walls and are filled with fatty material. Foam cells are often found in cases of atherosclerosis.

Coronary Atherosclerotic Heart Disease "Bad" cholesterol, also called low-density lipoprotein (LDL), has chemical properties that can damage arteries. Damaged areas allow more LDL to penetrate artery walls. The LDL gets stuck and accumulates in the artery's wall. "Good" cholesterol, known as high-density lipoprotein (HDL), is the yin to LDL's yang. HDL is on your side: it circulates through your body, acting like a cholesterol magnet. HDL diverts and delivers cholesterol away from your arteries. Much of the cholesterol is either eliminated from the body, delivered to tissues such as the liver, or used to make hormones.

Treatments Preformed in the Cardiac Catheterization lab (Cath Lab) Percutaneous Transluminal Coronary Angioplasty (PTCA) Coronary Stent Intra-coronary Thrombolysis

Coronary Stent - A Treatment for Coronary Atherosclerotic Heart Disease

Percutaneous Transluminal Coronary Angioplasty (PTCA)

Treatments Preformed in the Heart Room in the OR Suite Coronary Artery Bypass Grafting (CABG) Permanent pacemaker

Surgical Treatment : Coronary Artery Bypass Grafting (CABG)

Possible Grafts for CABG 1. Saphenous vein 2 Possible Grafts for CABG 1. Saphenous vein 2. Internal thoracic arteries (mammary) 3. Radial Artery For patients with triple-vessel disease undergoing CABG, radial artery grafts appear to be less likely than saphenous veins to become occluded in the long term, according to randomized trial.

Saphenous Vein Harvesting

Postoperative Healing

Endoscopic Saphenous Harvesting

Mammary Artery Harvesting

Internal Mammary Artery

Radial Artery Harvesting

Cardiopulmonary Bypass Identify the locations of the tube insertions into the circulatory system Venous cannulation: right atrium or venae cavae Arterial cannulation: ascending aorta

Permanent Pacemaker

Dysrhythmias Sinus Dysrhythmia – most common; related to vagal nerve impulses to the SA node; benign Sinus Tachycardia – heart rate of 100 beats or more per minute Sinus Bradycardia - heart rate of 60 beats or less per minute

Atria Dysrhythmias Dysrhythmias originating in the atria: Premature atrial beat – often associated with stress or consumption of caffeine or nicotine Atrial tachycardia – atrial rate of 150-250 beats per minute; usually benign Atrial flutter - atrial rate of 250-350 beats per minute; can result in increased ventricular rate and decrease in oxygen Atrial fibrillation - atrial rate of 350-600 beats per minute; results in increased ventricular rate and decrease in oxygen

Ventricular Dysrhythmias Benign PVC’s – less than 5 per hour; absence of heart disease Complex PVC’s – greater than 10-30 per hour; with or without heart disease Malignant PVC’s – same as complex except with left ventricular dysfunction Ventricular tachycardia – 140-250 beats per minute Ventricular flutter – regular contractions but at a fast rate of 250-350 per minute

Electrocardiogram ECG or EKG Electrical signals can be picked up form the body surface and transformed into visible tracings by an instrument called an electrocardiograph The electrocardiogram is the graphic record of the heart’s electrical activity

ECG 3 characteristic deflections or waves P wave – depolarization (triggers contraction) of atria QRS complex - depolarization (triggers contraction) of ventricles T wave - repolarization of ventricles

Cardiothoracic Procedures Features of the ECG Paper

ECG Electrical Correlation

Electrocardiograph (Normal Sinus Rhythm)

Sinus Rhythm

Occasional (Incidental) PVC

Bigeminy (PVC Every Other Beat)

Ventricular Fibrillation (V Fib)

Premature Atrial Contraction (PAC)

Atrial Fibrillation

Asystole