NCMB 312 Prelims Reviewer PDF

Property of: Alfie Velasco Section: BSN 3-Y1-11 DISTURBANCE IN PUMP MECHANISM Cardiovascular Anatomy and Physiology Heart- pumps oxygenated blood for systemic circulation by rhythmic relaxation and contraction - Layers of Heart Epicardium...

Property of: Alfie Velasco Section: BSN 3-Y1-11 DISTURBANCE IN PUMP MECHANISM Cardiovascular Anatomy and Physiology Heart- pumps oxygenated blood for systemic circulation by rhythmic relaxation and contraction - Layers of Heart Epicardium/Pericardium- outer layer of the heart, contains pericardial fluid that lubricates heart Myocardium- middle and the muscular layer of hearts; myocytes form the muscle fibers. One of the cardiac conduction system Endocardium- innermost layer of the heart. Provides protection of the valves Right Side of the Heart- venous blood = deoxygenated blood - Right atrium- receives deoxygenated blood from superior vena cava (Upper Extremities, Head and Neck) and inferior vena cava (Trunk, Lower extremities); it also receives deoxygenated blood from the coronary sinus from myocardium - Right ventricle- pumps blood to the pulmonary circulation via the pulmonary artery to reoxygenate Left Side of the Heart- arterial blood = oxygenated blood - Left atrium- receives blood from the lungs via 4 pulmonary veins - Left ventricle- pumps blood to the system circulation via aorta Valves- permits the blood to flow in one direction. Prevents the back flowing of blood - Atrioventricular valves- separates the atria and ventricles Tricuspid valve- permits blood flow from right atrium to right ventricle Bicuspid valve- aka Mitral; permits blood flow from left ventricle to aorta - Semilunar valves- heart valve at the base of the aorta and the pulmonary artery, and consisting of cusps or flaps that prevent the backflow of the blood during systole. Pulmonic valve- permits blood flow from the right ventricle to pulmonary artery Aortic valve- permits blood flow from left ventricle to systemic circulation Coronary Arteries- supplies blood to the heart primarily in the myocardium - Left Coronary Artery- 3 branches Left main coronary artery- first major branch; 2 branches arises from this namely: Left anterior descending artery- courses down the anterior wall of the heart; supplies blood to the left ventricle,ventricular septum, chordae tendineae, papillary muscle, right ventricle (lesser extent). Called the widow maker. Circumflex artery- circles around to the lateral left wall of the heart; supplies blood to the left atrium, lateral and posterior surface of the left ventricle, portion of interventricular septum, SA node and AV node - Right Coronary Artery- supplies blood to the right side of the heart, and inferior portion of the left ventricle. The posterior wall of the heart receives blood supply by the additional branch called the posterior descending artery I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 Cardiac Cycles- events that occur in the heart from the beginning of one heartbeat to the next. - Systole- period of ventricular contraction resulting from ejection of blood in ventricles - Diastole- period of ventricular relaxation resulting to ventricular filling Cardiac Conduction System- generates and transmits electrical impulses that stimulate contraction of the myocardium. - Physiologic characteristics: Automaticity- ability to initiate an electrical impulse Excitability- ability to respond to electrical impulses Conductivity- ability to transmit an electrical impulse from one cell to another - Autorhythmic- generates action potentials without nervous impulse ~Why does your heart contract? → nodal and purkinje cells, ions and myocardium. Sinoatrial Node- primary pacemaker of the heart; located at the junction of superior vena cava and right atrium. Has a firing rate of 60-100/min that will send signal to the right atrium to the left atrium. Conducts electricity to the AV node via internodal pathways Atrioventricular Node- secondary pacemaker of the heart; located right atrial wall near the tricuspid valve. Coordinates the incoming electrical impulses from the atria and after a slight delay (which allows the atria time to contract and complete ventricular filling) relays the impulse to the ventricles. Firing rate is 40-60/min; takes over if the SA node fails Bundle of His- transmit impulse to the right ventricle (right bundle branch) and left ventricle (left bundle branch), then transmit impulses to the terminal point of conduction system Purkinje fibers- terminal point of conduction system. Conducts impulses throughout the thick wall of the ventricles. This action stimulates the ventricular myocardial cells to contract. Firing rate is 30-40/mins. Cardiac Action Potential- repeated cycle of depolarization and repolarization; ions involved are potassium, calcium and sodium. Potassium primary intracellular cation (relaxed); Sodium primary intracellular cation (contracted) - Phase 0- initiated as positive ions influx into the cell. During this phase the atrial and ventricular myocytes rapidly depolarize as sodium moves into the cells through sodium-fast channels. In contrast, the cells of the SA and AV nodes depolarize when calcium enters these cells through calcium-slow channels. - Phase 1- early cellular repolarization begins during this phase as potassium exits the intracellular space - Phase 2- plateau phase; rate of repolarization slows. Calcium ions enter the intracellular space - Phase 3- marks the completion of repolarization and return of the cell to its resting state - Phase 4- considered the resting phase before the next depolarization. Dysrhythmia (arrhythmia)- any deviation from normal rate or pattern of heartbeat Refractory period- myocardial cells must completely repolarize before they can depolarize again. There are two phases: - Absolute refractory- the cell is completely unresponsive to any electrical stimulus - Relative refractory- corresponds with the short time at the end of phase 3. I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 Cardiac Hemodynamics- event occurs in the heart from one heartbeat to another to the next; involves blood flow - Higher pressure to one of lower pressure - Pressure changes in the chambers - Valvular functions are determinants Atrial systole- initiated by SA node; atrial muscle contracts Increased pressure in the atria - atrial kick (15-25% blood is added) ejection of blood into the ventricle after efficient opening of tricuspid and mitral valve Beginning of ventricular systole- in response to to electrical impulses; ventricular filling is complete Increase pressure in the ventricles- AV Valves closes; blocks blood flow to the ventricles Rapid increase of pressure inside ventricles- semilunar valves opens; blood is ejected to pulmonary circulation and systemic circulation Rapid decrease of pressure in the ventricles- decrease of pressure in the pulmonary artery and aorta closes semilunar valves Cardiac Output- total volume of blood pumped by the heart per minute; Stroke Volume (SV) x Heart Rate (HR)/min: Normal range is 5L/min, depending on the metabolic needs. Stroke volume- the amount of blood ejected to the ventricles every heartbeat 2D echocardiogram (EDV-ESV): Normal range for adult is 70mL - End Diastolic Volume- amount of blood inside ventricle before contraction (130mL) - End Systolic Volume- amount of blood left in the ventricle after ejection (60mL) Control of HR- accomplished by reflex control and baroreceptors (Normal Adult range 60-100 bpm) - Baroreceptors are specialized nerve cells located in the aortic arch and in both right and left internal carotid arteries, at the point of bifurcation from the common carotid arteries. These are sensitive to changes in blood pressures. During hypertension, these cells increase their rate of discharge, transmitting impulses to the cerebral medulla. This action initiates parasympathetic activity and inhibits sympathetic response, lowering the heart rate and the BP. Control of SV- determined by 3 factors: - Preload- degree of stretch of the ventricular muscle at the end of relaxation/diastole. Filling volume in the ventricles is the highest Frank-Starling Law- states that the greater the initial length or stretch, the greater the degree of shortening that occurs. (increased EDV = increased preload = increased forceful contraction = increased systolic volume) - Afterload- resistance to ejection of blood to the ventricle Systemic vascular resistance- resistance of left ventricles toward systemic circulation Pulmonary vascular resistance- resistance of right ventricle toward pulmonic circulation There are inverse relation between preload and afterload; constriction in arteries decreases stroke volume while dilation occurs it increase stroke volume I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 - Contractility- force generated by the contracting myocardium Ejection fraction- percentage of blood left in ventricles; normal range is 55-65%. Less than 40% suggest of heart failure Cardiovascular Assessment and Diagnostics Common Symptoms: - Chest pain or discomfort- angina pectoris, acute coronary syndrome, arrhythmias, valvular diseases - Pain or discomfort in other areas of the body, including one or both arms, back, neck, jaw or stomach- ACS - Shortness of breath or dyspnea- ACS, cardiogenic shock, heart failure, valvular diseases - Peripheral edema, weight gain, abdominal distention- heart failure - Palpitations- tachycardia from a variety of causes, including ACS, caffeine or other stimulants, electrolyte imbalances, stress, valvular diseases, ventricular aneurysm - Unusual fatigue, sometimes referred as vital exhaustion- early sign of ACS, heart failure, or valvular diseases - Dizziness, syncope or alterations in consciousness- cardiogenic shock, cerebrovascular disorders, arrhythmias, hypotension, orthostatic hypotension, vasovagal episodes. Pulse pressure- difference between the systolic and diastolic pressure; determines the maintenance of good cardiac output: Normal value is 30-40 mmHg - Increased or widened pulse pressure = Anxiety, Exercise, Bradycardia, Increased Intracranial pressure - Decreased or narrowed pulse pressure = shock, heart failure, hypovolemia Jugular Vein Pulsation- can be a means to estimate right-side heart function. SITE: just above the clavicles adjacent to the sternocleidomastoid. Normally distended when a patient is lying flat/supine. Not apparent if the head is elevated more than 30 degrees. Distention with head elevated at 45-90 degrees means right ventricular failure, pulmonary hypertension or pulmonary stenosis Inspection and Palpation of Heart- find the angle of louis located at the bony ridge top of the sternum at the junction of the body and the manubrium of the sternum. - Aortic area- 2nd intercostal space space right sternum - Pulmonic area- 2nd intercostal space to the left of the sternum - Erb’s point- 3rd intercostal space left of the sternum - Tricuspid area- lower half of the sternum along the left parasternal area - Mitral (apical) area- left 5th intercostal space at the midclavicular line - Epigastric area- below the xiphoid process I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 Auscultation of Heart- S1 and S2 normal heart sound; produces via closing of valves - S1- closure of AV valves; “Lub” sound, loudest at the apical area. Intensity increases during tachycardia or mitral stenosis - S2- closure of semilunar valves; “Dub” sound. Aortic component is heard loudest Abnormal heart sounds: - S3- “Lub-dub dub” occurs early in diastole during the period of rapid ventricular filling. In older adults it is a sign of significant pathophysiology Physiologic S3- normal on children and adults ages 35-40 y/o - S4 “Lub dub-dub” generated during atrial contraction as blood forcefully enters non compliant ventricles. Occurs late in diastole - Summation gallop- both S3 and S4 present. Creating quadruple rhythm “Lub lub-dub dub” - Friction rub- harsh grating sound caused by abrasion of inflamed pericardial surface from pericarditis - Murmurs- created by turbulent blood flow caused by; narrowed valves, congenital defects, defects between aorta and pulmonary artery Location- assess where the murmur is heard; Ex: Murmur located at the left sternal border between 4th and 5th intercostal space suggests ventricular septal defect Intensity- loudness of a murmur Grade 1- very faint and difficult for the inexperienced clinician to hear Grade 2- quiet but readily perceived by the experienced clinician Grade 3- moderately loud Grade 4- loud and mat be associated with thrill Grade 5- very loud; heard when stethoscope is partial off the chest; associated with thrill Grade 6- Extremely loud; detected with the stethoscope off the chest; associated with thrill Pitch- describes the sound frequency; high-pitched murmurs heard best with stethoscope diaphragm while low-pitched murmurs best heard with bell of the stethoscope Quality- describes the sound that the murmur resembles; Ex: rumbling, blowing, whistling etc etc Radiation- transmission of the murmur from the point of maximal intensity to the other areas in the upper chest. Assessment of the other system - Left Sided Heart Failure- will manifest pulmonary symptoms: Hemoptysis, coughing, crackles, wheezes - Right Sided Heart Failure- will manifest abdominal distention, hepatojugular reflux and bladder distention Cardiac Biomarkers- aids in diagnosing conditions associated with insufficient blood flow. Cardiac enzymes may indicate heart damage. I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 - Creatinine-Kinase (CK)- primarily found in the heart and the skeletal muscles. Suggest injury to the muscles if elevated - CK-MB- creatine-kinase isoenzyme; suggests injury to the heart muscles if elevated - Myoglobin- captures oxygen that muscle cells use for energy. Found in cardiac and skeletal muscle - Troponin I and T- found in cardiac muscle measured along with other cardiac biomarkers. Most definitive cardiac biomarkers to diagnose MI - Lipid profile- presence of fats in blood/blood vessels Cholesterol- 50 y/o = 40-190 mg/dl 2D Echocardiography- ultrasound for the heart; measures the ejection fraction, examines the size, shape, structure and determines the etiology of murmurs. Evaluates function of the valves and ventricular walls. Helps to diagnose pericardial effusion - Transesophageal echocardiography- approach through mouth and into esophagus. Provides clearer images Cardiac catheterization- invasive diagnostic procedure in which radiopaque arterial and venous catheters are introduced into the selected blood vessels of the right or left side of the heart. Use to the diagnose CAD, assess coronary artery patency and extent or atherosclerosis - Nursing Considerations: Post op: require 2-6 hours rest; watch out for bleeding If Arm or Wrist was used, avoid lifting >5lbs. If bleeding occurs allow patient to sit If the groin was used, do not bend at the waist. If bleeding occurs allow patient to lie down Angiography- a technique in which a contrast agent is injected into the vascular system to outline the heart and blood vessels. Helps to diagnose congenital heart lesions, disease of aorta, pericardium and myocardium - Nursing Consideration: Pre op: inquire patient about their allergies specially to iodine or seafood Carotid artery duplex scan- ultrasound of vascular. Provides 2D image of arteries. Assess occlusion or stenosis and degree of blood flow. Absence or faintness of sound suggest obstruction to the blood flow Cardiac Stress Test- non invasive ways to evaluate if there is myocardial ischemia and higher myocardial oxygen requirement during stress. - Cardiac Exercise Stress Test- the patient walks or runs on the treadmill (most common) or pedals a stationary bicycle. I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 - Pharmacologic Stress Test- patient is given a vasodilating agent (Dypyridamole, Adenosine, Dobutamine) and reversed by aminophylline. Stress Tests help diagnose CAD, determine functional capacity of the heart after myocardial infarction. Evaluates the effectiveness of anti-anginal or antidysrhythmic drugs. Target HR is 80-90% average base on age - Nursing Consideration (Pharmacologic Stress test) Inform patient about the side effect of the vasodilating agents (headache, nausea, vomiting) Avoid caffeine and xanthines Electrocardiogram (ECG)- series of waves and deflections recording the heart’s electrical activity from a certain view. Each wave of cardiac cycle is reflected by specific waveforms - Placement of ECG electrodes Red- right arm Yellow- left arm Black- right leg Green- left leg V1- 4th intercostal space right of sternum V2- 4th intercostal space left sternum V3- directly between V2 and V4 V4- 5th intercostal space left midclavicular line V5- 5th intercostal space anterior axillary line V6- 5th intercostal space midaxillary line Limb electrodes - Right leg leads does not illicit electrical impulses; minimizes artifacts Artifacts- unnecessary waveforms - Views heart in a vertical plane aVR = Right Arm I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 aVF = Left leg aVL = Left arm - Unipolar, + electrode Right Arm (-,-) ; Left Arm (+,-) ; Left Leg (+,+) Right Arm + Left Arm Lead 1 Right Arm + Left Leg Lead 2 Left Arm + Left Leg Lead 3 - Bipolar; +,- electrodes Einthoven’s triangle: - aVR = upper right side of the heart - aVF = upper left side of the heart - aVL = inferior portion of the heart Lead 1 = top part of the lateral wall Lead 2 = Right side of inferior wall Lead 3 = left side of inferior wall heart Chest Leads: - V1-V2 = intraventricular septum - V3-V4 = anterior wall of heart - V5-V6 = lateral wall of the heart Localization of Heart - Inferior: II, III, aVF - Septal: V1, V2 - Anterior: V3, V4 - Lateral: I, aVL, V5, V6 Anatomy of ECG I was filled with poison, but blessed with beauty and rage ~St. Lana Del Rey Property of: Alfie Velasco Section: BSN 3-Y1-11 P-wave- right and left contraction and electrical wave from SA node. 2.5mm in height, 0.11 seconds PR segment- time the wave of depolarization from AV nodes to the bundle of His. 0.04 seconds Q-wave- start of ventricular contraction; negative deflection