EKG Interpretation PDF

lOMoARcPSD|22650627 EKG Interpretation Electrical Pathway through the Heart Electro...

lOMoARcPSD|22650627 EKG Interpretation Electrical Pathway through the Heart Electrocardiogram (EKG or ECG) - represents movement of electrical current through the heart during a heartbeat Sinoatrial Node (SA node) Bachmann's Bundle Terms Internodal Pathways Depolarization - change in electric charge Left Bundle distribution, resulting in more positive ions; Atrioventricular Branch occurs with contraction of heart Node (AV node) Repolarization - return of the ions to the Bundle of His previous resting state; occurs with relaxation of Right Bundle heart Branch Automaticity - ability to generate impulses Purkinje Fibers automatically without being stimulated to do so If automaticity is increased or decreased, an arrhythmia can occur Impulse starts in SA Node (Sinoatrial node) AKA 'pacemaker;' 60 - 100 bpm Re-entry - when impulse follows a circular conduction path Flows down through the internodal pathways to the AV node Atrial kick - amt of blood pumped as a result of (Atrioventricular node) AKA 'gatekeeper,' 40 - 60 bpm atrial contraction, about 30% of cardiac output Causes a needed delay so the atrium can fully empty into the ventricles Flows through Bundle of His to right and left bundle branches Pacemaker cells of the heart Flows to Purkinje Fibers; 20 - 40 bpm; then starts all over again Primary - SA node; 60 - 100 bpm Secondary - If SA node does not function 12-Lead Electrode Placement properly, secondary cells will become ectopic pacemaker cells 10 leads total (4 limb and 6 chest) AV junction - tissue surrounding the AV RA: On the Rt arm or right below the Rt clavicle node; called junctional tissue; first in line LA: On the left arm or right below the left to take over SA node's function; 40 - 60 clavicle bpm RL: On the right leg or upper right quadrant Bundle of His, Bundle Branches and LL: On the left leg or upper left quadrant Purkinje fibers - called His-Purkinje V1 (Red): 4th intercostal space, to the right of system; 20 - 40 bpm the sternum V2 (Yellow): 4th intercostal space to the left of the sternum 5-Lead Electrode Placement V3 (Green): Midway between V2 and V4 V4 (Blue): 5th intercostal space in the mid- RA (White) - near right mid-clavicular line, clavicular line directly below clavicle V5 (Orange): Level with V4 at the left anterior C (Brown) - to right of sternum at 4th mid-axillary line intercostal space V6 (Purple): Level with V5 at the mid-axillary line RL (Green) - between 6th and 7th intercostal space on mid-clavicular line To help remember: Prep skin: LA (Black) - near left mid-clavicular line, White to the right Wash w/soap & water; dry directly below clavicle Snow over trees Clip dense hair LL (Red) - between 6th and 7th intercostal Smoke over fire 'Rough up' skin w/back of electrode space on mid-clavicular line Chocolate close to heart Clean w/alcohol pad; air dry  lOMoARcPSD|22650627 EKG Interpretation Interpreting a Rhythm Strip QT Interval PR Interval ST Segment QRS Complex P Wave - *Atrial Depolarization ST Segment Distance between Location: precedes the QRS complex P waves = atrial Location: from end of S wave to beginning of T wave Duration: 0.12 second may be ventricular U Wave conduction delay Location: following T wave; not always seen Absent: AV block or ventricular standstill Configuration: upright and rounded Abnormality & possible cause: Prominent: hypercalcemia, hypokalemia, or digoxin Age matters when reading an EKG: ↑ Older adults have PR, QRS and QT intervals toxicity ↓ Children have PR and QRS intervals  lOMoARcPSD|22650627 EKG Interpretation Measurements Measuring an interval or complex Count the small boxes between the start and end of the interval The squares on the EKG paper (behind or complex then multiply by 0.04 the rhythm) represent time PR interval - start measuring at the beginning of the P wave 1 small square = 0.04 second until the beginning of the QRS complex 1 large square = 0.20 second QRS complex - start measuring at the end of the PR interval 5 large squares = 1 second until the end of the S wave 30 large squares = 6 seconds QT interval - start measuring at the beginning of the QRS complex until the end of the T wave 6 0.04 second second rule to count heart rate 0.20 second Identify the P waves (Atrial rate) Count out 30 large squares starting at the first P wave 1 second Count the number of P waves between the large squares Multiply that number by 10 to get the heart rate May also use R waves (ventricular rate) instead of P waves 8 Steps of EKG Interpretation 1 Determine rhythm 5 Determine duration of QRS complex Measure distance between P waves; note if irregular Between 0.06 and 0.12 second? Measure distance between R waves; note if irregular All complexes the same size and shape? If irregular, is it slightly or markedly? Does the Do they appear after every P wave? irregularity occur in a pattern? Variations of up to 0.04 second are normal 6 Evaluate T waves 2 Determine heart rate Are they present? All have normal shape? Calculate atrial and ventricular rates Same deflection as the QRS complexes? Normal 60 - 100 bpm Tachycardia: >100 bpm Bradycardia: 48 hrs Pericardial disease, primary myocardial disease If cannot perform cardioversion: Meds: diltiazem (Cardizem); verapamil (Calan) or digoxin 'flutter waves' to slow ventricular rate; amiodarone to slow rate and convert rhythm ↓ Monitor pt for s/s of CO Atrial Fibrillation (A-fib) Signs/Symptoms: Chaotic, asynchronous, electrical activity in atrial tissue Radial pulse rate often slower than apical rate From firing of a number of impulses in multiple re-entry ↓ May see s/s of CO: hypotension, light-headedness pathways; fire so fast that atria quivers ↓ Results in loss of atrial kick (will CO) Treatment/Interventions No P waves, instead erratic baseline waves called Goal to reduce vent rate to 400 bpm After successful cardioversion, meds to maintain normal sinus Vent rate 100 - 150 bpm rate and control ventricular rate: Causes: Metoprolol (Lopressor), atenolol (Tenormin), esmolol After cardiac surgery (Brevibloc), propranolol (Inderal), diltiazem (Cardizem), Long-standing HTN verapamil (Calan), amiodarone (Cordarone) Diabetes, obesity May need radiofrequency ablation therapy if cardioversion Obstructive sleep apnea unsuccessful Smoking ↓ Monitor: s/s of CO and heart failure; serum drug levels, Pulmonary embolism, COPD watch for toxicity Electrolyte imbalances Instruct pt: report pulse rate changes, syncope or dizziness, Mitral insufficiency or stenosis chest pain, dyspnea, peripheral edema Hyperthyroidism CAD, acute MI, pericarditis, hypoxia, atrial septal defects fibrillatory waves irregular intervals  lOMoARcPSD|22650627 EKG Interpretation - Arrhythmias Junctional Arrhythmias Impulse originates in the AV junction In junctional arrhythmias, the P wave will Location of P wave be inverted (might not be seen at all) Location of P wave will be: Before QRS complex (atria depolarized 1st) (hidden) After QRS complex (ventricles Atria Atria & ventricles Ventricles depolarized 1st) OR depolarized 1st depolarized same time depolarized 1st Hidden in QRS complex (both atria and ventricles depolarized at same time) Atrial arrhythmia vs Junctional arrhythmia PR interval will be short if measurable Look at PR interval! QRS complex, T wave and QT interval are Normal PR interval originated in the atria normal Shortened PR interval originated in the AV junction Wolff-Parkinson-White syndrome Signs/Symptoms: Bypass forms (bundle of Kent) to conduct impulse Dizziness, syncope, palpitations, SOB, possibly cardiac arrest Shortened PR interval (0.10 second); beginning is Treatment/Interventions slurred Must be treated if a-fib or atrial flutter occur Hallmark = delta wave delta wave Meds such as adenosine or amiodarone Causes: Radiofrequency ablation if resistant to meds Congenital rhythm disorder Impulse originates in PVC V-fib Ventricular Arrhythmias ventricles below Bundle of His V-tach Asystole Premature Ventricular Contraction (PVC) Causes: Ectopic beat; may occur in healthy people w/no problem Electrolyte imbalances: hypokalemia, hyperkalemia, May occur singly or in clusters of two or more or in hypomagnesemia, hypocalcemia repeating patterns (bigeminy or trigeminy) Metabolic acidosis PVCs in a pt with heart disease may be lethal Hypoxia ↓ Atrial kick lost, so CO (by 30%) Myocardial ischemia and infarction Drug intoxication P wave absent w/PVC wave QRS complex comes early; duration >0.10 second Myocarditis Pause after QRS complex Caffeine/alcohol/tobacco use Signs and Symptoms: Treatment/Interventions With frequent PVCs: palpitations, hypotension, syncope No tx if asymptomatic If symptomatic, tx will depend on cause paired PVCs Meds: amiodarone, lidocaine, IV potassium chloride or orally if hypokalemia, magnesium sulfate IV to correct hypomagnesemia If s/s serious, continuous EKG monitoring  lOMoARcPSD|22650627 EKG Interpretation - Arrhythmias Ventricular Arrhythmias, cont. Causes: Myocardial ischemia or infarction Ventricular Tachycardia (V-tach) CAD, valvular heart disease Heart failure, cardiomyopathy 3 or more PVCs in a row plus vent rate >100 bpm Electrolyte imbalances Extremely unstable and unpredictable Drugs: digoxin, procainamide, quinidine, cocaine, meta-amphetamines May be in short bursts or sustained (emergency) Can quickly deteriorate to V-fib and complete cardiac Treatment/Interventions collapse Tx depends on if pulse is detectable or not Atrial rate and rhythm indiscernible Pulseless: Vent rhythm regular Immediate defibrillation and CPR Vent rate rapid 100 - 250 bpm Pulse present: Tx depends on stability and whether QRS complexes P wave absent or hidden in QRS are monomorphic (uniform shape) or polymorphic (shape changes) PR interval indiscernible Unstable: HR>150 bpm; cardioversion QRS complex wide and bizarre (>0.12 second) Stable w/monomorphic QRS: ACLS followed by amiodarone to Signs/symptoms: correct rhythm; cardioversion if unsuccessful Weak or absent pulse ↓ Hypotension, LOC Stable w/polymorphic QRS: If normal QT interval: correct ischemia and electrolyte QRS complex wide & bizarre imbalances; amiodarone, lidocaine, beta-adrenergic blockers, then ACLS protocol; cardioversion if unsuccessful If prolonged QT interval: correct electrolyte imbalances; administer magnesium IV; if unsuccessful, over-drive pacing Chronic V-tach: implantable cardioverter-defibrillator (ICD) implanted Ventricular Fibrillation (V-fib) Signs/symptoms: Chaotic pattern of electrical activity in the ventricles Pt is in full cardiac arrest, unresponsive , no BP or pulse Produces NO muscular contraction or CO Causes: Causes most cases of sudden cardiac death outside of Myocardial ischemia or infarction Severe hypothermia hospital Untreated V-tach Electrolyte imbalances Ventricles quiver and do no contract; will see fibrillating Underlying heart disease Drug toxicity (e.g. digoxin) waves with no pattern Acid-base imbalance Severe hypoxia Cannot determine: rate, rhythm, QRS complex & Electric shock intervals Treatment/Interventions May be either coarse or fine waves on strip May mimic V-fib: shivering; electrical interference Defibrillation most effective tx especially within 2 minutes of V-fib starting large fibrillatory waves small fibrillatory waves Perform CPR until defibrillator arrives 'coarse' OR 'fine' Assist with endotracheal intubation May be administered: *easier to convert* Epinephrine, amiodarone, lidocaine, magnesium sulfate Treatments Defined Defibrillation - pt has no pulse; controlled electric shock delivered to restore normal rhythm; delivered randomly Cardioversion - pt has pulse; controlled electric shock delivered to restore normal HR; usually timed/synchronized with QRS complex; often used for fast/unstable HR Transcutaneous pacing - pt has pulse; controlled pulses delivered during medical emergency; usually for slow HR Radiofrequency ablation - AKA cardiac ablation; tube guided into heart to destroy small areas of tissue that may be causing an abnormal HR  lOMoARcPSD|22650627 EKG Interpretation - Arrhythmias Ventricular Arrhythmias, cont. Asystole ('arrhythmia of death') Sign/Symptoms: Ventricular standstill Pt unresponsive w/o any pulse or blood pressure Pt unresponsive w/no electrical activity in heart, no pulse, Causes: no BP and no CO MI Electric shock Usually from prolonged pd of cardiac arrest Severe electrolyte imbalances Drug intoxication (e.g. cocaine) Must be confirmed w/more than one ECG lead to make Massive pulmonary embolism Cardiac tamponade sure it is not V-fib (fine) Prolonged hypoxemia Hypothermia Looks like nearly flat line on strip Severe acid-base disturbances Treatment/Interventions nearly flat line Confirm pt has no pulse then begin CPR Administer epinephrine and atropine as ordered Transcutaneous pacing will follow Once stable, treat cause First-degree Type II second-degree Atrioventricular Blocks Type I second-degree Third-degree Interruption in the impulses Can be total, partial or a delayed conduction Occurs at AV node, Bundle of His, or bundle branches between atria and ventricles Can be temporary or permanent Classified according to severity, not location First-degree AV block Impulses from atria are delayed during conduction through Sign/Symptoms: the AV node None; CO not significantly affected May be temporary or progress to more severe block Causes: Looks like NSR but PR interval longer than normal (PR May appear in healthy person Meds: digoxin, calcium channel interval >0.20 second) Myocardial ischemia/MI blockers, beta-adrenergic Myocarditis blockers PR interval longer than 0.20 second Treatment/Interventions Underlying cause treated Monitor closely to detect progression of block Type I second-degree AV block AKA Mobitz type I block or Wenckebach Sign/Symptoms: Each impulse from SA node delayed longer than previous None usually; may see s/s of ↓CO (light-headedness, hypotension) Eventually impulse fails and cycle repeats Causes: Block usually in AV node and temporary CAD, inferior wall MI Meds: digoxin, calcium channel Atrial rhythm normal; T wave inverted Rheumatic fever blockers, beta-adrenergic PR interval gradually gets longer until eventually QRS Increased vagal stimulation blockers complex dropped; 'longer, longer, drop' Treatment/Interventions 'longer, longer, drop' No tx if asymptomatic Symptomatic: atropine; temporary pacemaker may be needed ↑ Assess pt tolerance for the rhythm and need to CO Monitor ECG to make sure block does not progress  lOMoARcPSD|22650627 EKG Interpretation - Arrhythmias Atrioventricular Blocks, cont. Sign/Symptoms: Type II second-degree AV block Asymptomatic at first AKA Mobitz type II block As number of dropped beats increases, pt may report palpitations, Less common than Type I second-degree but more serious fatigue, dyspnea, chest pain or light-headedness Occurs when SA impulses fail to conduct to ventricles May note hypotension and slow or irregular pulse Will see dropped QRS complexes Causes: Atrial rhythm regular; vent rhythm usually irregular Problem occurs at bundle of His or bundle branches P wave and PR interval usually constant Anterior wall MI; severe CAD QRS complex may be wide 2:1 AV block: every other QRS complex is dropped Treatment/Interventions Highly likely to progress to more severe block ↓ → If no symptoms of CO and dropped beats infrequent monitor QRS complex dropped ↑ If hypotensive, tx will be to improve CO by HR: Atropine, dopamine, epinephrine; discontinue digoxin if cause Transcutaneous pacing Often requires pacemaker atrial rhythm regular; ventricular irregular Bed rest; O2 therapy as ordered Third-degree AV block Sign/Symptoms: AKA Complete heart block Severe fatigue, dyspnea, chest pain, light-headedness →↓ Atrial kick lost CO; life-threatening! Changes in mental status, pulmonary edema, LOC Hypotension, pallor, diaphoresis, bradycardia Impulses from atria are completely blocked at the AV node and cannot be conducted to ventricles Causes: Will see normal P waves but independent of QRS complex Congenital condition Both rates and rhythm regular CAD; anterior or inferior wall MI PR interval varies Digoxin toxicity Calcium channel blockers, beta-adrenergic blockers P waves independent of QRS complex Treatment/Interventions ↑ Atropine or temp pacemaker to CO; dopamine and epinephrine rates and rhythm regular Temporary pacing until block resolves or pacemaker inserted Make sure pt has patent IV catheter Administer O2 therapy as ordered Bed rest Sinus Bradycardia - NSR spaced out Sinus Tachycardia - NSR squished together Sinus Type II 2nd- AFlutter - flutter waves Atrial Flutter Asystole Bradycardia PVC degree Afib - No P waves; fibrillatory waves instead Arrhythmia Key Junctional - inverted P wave; short PR interval PVC - QRS complex comes early w/pause after Sinus 1st-Degree V-tach - QRX complex wide and bizarre Atrial 3rd-Degree Tachycardia V-tach AV block AV block V-fib - coarse or fine waves fibrillation Asystole- almost flat line 1st-degree - large PR interval Type I 2nd-degree - T wave inverted; PR interval (longer, Type I 2nd- V-fib degree longer, drop) Junctional Type II 2nd-degree - QRS complex dropped 3rd-degree - P waves and QRS complexes completely separate