Cardiac Dysrhythmias PDF

Welcome to Unit 4 on Cardiac dysrhythmias  UNIT 4. Patients with Dysrhythmias Topic Learning Objectives After completion of this module, the student is expected to : Describe the common atrial and ventricular dysrhythmias Explain the pathophysiology and causes of dysrhythmias Anticip...

Welcome to Unit 4 on Cardiac dysrhythmias  UNIT 4. Patients with Dysrhythmias Topic Learning Objectives After completion of this module, the student is expected to : Describe the common atrial and ventricular dysrhythmias Explain the pathophysiology and causes of dysrhythmias Anticipate the measures to be done in patients with dysrhythmias Studies on Dysrhythmias Khurshid et.a.l(2018 ) – many hypertensive, renal and heart failure patients develop abnormal rhythms Contributes to the higher morbidity and mortality rate in cardiovascular disorders.  Self assessment – label the conduction system: Anatomy and physiology review of the Cardiovascular system The heart has four chambers 2 atria 2 ventricles 4 heart valves Heart Valves 1. Atrioventricular valves: Tricuspid & Mitral 2. Semilunar valves: - Aortic and Pulmonic  Why are the valves very important ? Valves prevent the backflow of blood for a one way direction or forward flow during the heart contractions. Blood Flow Blood Flow Cardiac Function Parameters Heart Rate – Normally , the heart beats 60 to 100 times per minute. Variations - caused by age, activities and exercise,, hormones, blood pressure, infections, stress like anxiety or pain. Terms : Bradycardia- beats less than 60 per minute- may be due to excessive exercise or effect of drugs especially betablockers. Tachycardia – heart beats more than 100 per minute. 1. Stroke volume – the amount of blood ejected with each contraction. about 60-100 ml. in the average sized adult 2. Cardiac Output: Adults : 4 - 8 liters CO= (EDV-ESV)X HR EDV is about 140 ml in adults Cardiac output … This may be measured also by a swan –Ganz Catheter. Average cardiac output in an adult weighing 70 kilos is 5-6 liters or 5000 to 6000 ml. /minute.  swan –Ganz Catheter used also to measure cardiac output Electro physiologic properties of heart muscles. 1. Automaticity ( Rhythmicity) – ability of cardiac cells to initiate an electrical impulse spontaneously and repetitively without neuro hormonal control Electro physiologic properties…. 2. Excitability-ability of cardiac cells to respond to an electrical impulse- may be influenced by hormones, electrolytes, medications , oxygen supply, infections or autonomic nervous system Electro physiologic properties…. (Excitability) Electro physiologic properties 3. Conductivity- ability of the cardiac cells to transmit an electrical impulses across the cell membranes Electro physiologic properties… 4. Contractility - the capacity to contract or produce a force or tension in the heart muscles – influenced by the movements of sodium, calcium and potassium ions inside and outside of the cells. Electro physiologic properties…. D. Impulse Conduction of the heart …. 4 major parts of the electrical conduction a. Sino atrial Node ( SA node ) b. Atrioventricular node ( AV node) c. Bundle of His d. Purkinje Fibers Impulse Conduction …. Action potential Contraction is initiated with a brief change in voltage (membrane potential) across the cell membrane of heart cells as affected by ion channels action potential … Cardiac Disturbances May be caused by : disturbances in the action potential anatomical and physiologic problems Infections E. Refractoriness of Heart muscles : heart muscles are not able to respond to any stimulus to prevent the tetanic contractions as seen in the skeletal muscles in action potential.  Lets watch this video about cardiac system.. https://youtu.be/RYZ4daFwMa8 The Normal Electrocardiogram Electrocardiogram ( ECG) – a recording of the electrical conduction of the heart on an ECG paper or strip Electrocardiogram Wave forms : P= first positive deflection -atrial depolarization  QRS wave -represents ventricular contraction/depolarization Electrocardiogram.. T wave –represents return of ions to former side of cell membrane or relaxation of muscle fibers Lets watch this video about ECG https://www.youtube.com/watch ?v=AUn8P5hRG0c  Atrial Dysrhythmias Atrial Fibrillation -the atrium generates very fast rate ( 400 to more than 600 times per minute) but quivering electrical impulses b. Irregular R to R wave Features: a. Irregualr R to Rinterval. b. most common atrial arrhythmia c.Occurs more in the older people  Patient Assessment and diagnosis : Medical History & P.A to check: Vital signs ECG rhythm strips Electrolyte imbalances Previously given medications- digitalis may cause atrial Fib. endocrine problems hyperthyroidism or severe sympathetic stimulation (stress) Management of Atrial Fibrillation 1.Antiarrhythmic drugs are used initially 2.Cardioversion- if patient is symptomatic 3.Oral anti coagulants- dabigatran, rivaroxaban, apixaban, and edoxaban) are recommended over warfarin Management of Atrial Fibrillation 4.Catheter ablation if recurrent and uncontrolled 5.Percutaneous left atrial appendage (LAA) occlusion – done in uncontrolled AF to prevent increased risk of stroke if they have contraindications to long term anticoagulation.  Premature Atrial Contractions heartbeat that originates away from the sinus node, sends electrical signals before the next regular sinus discharge a.Ectopic, originating outside of the SA node, P wave different from the normal sinus P wave morphology. b. Narrow complexes; - come from the atrium c. Compensatory pause following the contraction  Atrial Flutter coordinated rapid beating of the atria ranging from 150 to 300 beats per minute Saw tooth baseline in V1 with flutter waves. Narrow complex tachycardia - heart rate of 150 bpm makes this flutter with a 2:1 block. c. No visible P waves. d. Flutter waves are concealed in the T waves and QRS complexes Sinus Dysrhythmias 1. Sinus Tachycardia Sinus Bradycardia Atrioventricular blocks partial or complete interruption of impulse transmission from the atria to the ventricles. common cause is idiopathic fibrosis and sclerosis of the conduction system.  Common causes of AV blocks: Idiopathic fibrosis and sclerosis of the conduction system (about 50% of patients) Ischemic heart disease (40%) Drugs (eg, beta-blockers, CCB, digoxin, amiodarone) Increased vagal tone Valvulopathy Congenital , genetic, or other disorders  First degree AV block PR interval is greater than 0.20 seconds Features: a. No disruption of atrial to ventricular conduction b. Other complexes are normal No treatment is required Second Degree AV Blocks  Treatment of Second Degree AV Blocks a. Assess quickly the possible cause but do not delay treatment b. Open airway c. Connect to monitor to establish bradycardia d. Give atropine (0.5 mgs and repeat every 3 to 5 minutes till Bp acceptable (100/60mmHg)  Treatment of Second Degree AV Blocks e. Address the cause (ischemia, myocarditis, increased vagal tone, status post-cardiac surgery, or even medications ( beta- blockers, adenosine, digitalis, f. Additional lab/ work ups to determine other problems  3rd Degree AV Block a. No impulses conducted -No electrical communication between the atria and ventricles - they contract on their own. 3rd Degree AV Block Cardiac function is maintained by an escape junctional or ventricular pacemaker. Escape rhythms originating above the bifurcation of the His bundle produce narrow QRS complexes, Treatment : a. Pacemaker b. If the block is caused by antiarrhythmic drugs, stopping the drug may be effective, although temporary pacing may be needed. c. Atropine if due to acute inferior myocardial infarction causing atrionodal block Ventricular Dysrhythmias Ventricular tachycardia Ventricular Fibrillation  Watch these videos to understand better the ventricular dysrhythmias https://www.youtube.com/watch? v=W8VI1sf4SjQ dysrhythmias https://www.youtube.com/watch ?v=6LrptveKYus Nursing Care of the patient with dysrhythmias 1. Assess vital signs frequently to detect changes in hemodynamic parameters- blood pressure and oxygen saturation may suddenly drop in severe bradycardias and the lethal rhythms. Nursing Care 2. Maintain bed rest. ( injuries often happen when they collapse out of bed). 3.Check and prepare defibrillator ( charged and functional incase needed). Nursing Care 4. Closely watch for changes in the ecg changes – increasing frequency of PVC be reported on time 5. Adjust anti arrhythmic drug dose according to prescribed infusion rates Nursing Care 6. Identify possible triggers like stress , caffeine or medications 7. Provide information on patient’s medications and encourage compliance 8. Encourage patient to report any chest pains (- often from cardiac ischemia). NOTE !!! One most important nursing focus of care to patients with dysrhythmia is decrease in cardiac output therefore nursing interventions must be geared towards preventing this or immediately addressing an actual problem.  Thank you.