Basicekgft chapter7-8 ppt
- 1. Basic EKG Interpretation CHAPTER 7 / 8: VENTRICULAR ARRHYTHMIAS / AV BLOCKS Accompanying Textbook: ECG Interpretation Made Incredibly Easy, 5th Ed. © 2011 by Lippincott Williams & Wilkins. All rights reserved Instructed by: Douglas J Michel, PMD
- 2. 2 2018 © MediPro Presentation Template www.website.com PRIMARY VENTRICULAR RHYTHMS V E N T R I C U L A R A R R H Y T H M I A S Chaotic electrical activity within the ventricles that does NOT produce any effective contractions. This a lethal rhythm if not treated promptly. VENTRICULAR FIBRILLATION Slow rhythm originating in the Purkinje fibers acting as the third and final pacemaker site of the heart. This backup mechanism is designed to provide enough blood flow for the body to survive, however cannot be maintained long term. IDIOVENTRICULAR RHYTHM Rapid rhythm originating in the ventricles causing rapid ventricular contraction with no corresponding atrial contraction. Highly unstable rhythm that may degrade into a lethal rhythm if not treated. VENTRICULAR TACHYCARDIA IDIOVENTRICULAR RHYTHM VENTRICULAR FIBRILLATION VENTRICULAR TACHYCARDIA
- 3. 3 2018 © MediPro Presentation Template www.website.com 3 2018 © MediPro Presentation Template Ventricular Tachycardia is characterized by a wide complex rhythm with no associated P waves and a rate over 100 bpm. PR INTERVAL: NONE QRS INTERVAL: > 0.12 QT INTERVAL: 0.36-0.44 T WAVES – Normal in appearance RHYTHM - Regular P WAVE MORPHOLOGY: NONE HEART RATE: Over 100 bpm VENTRICULAR TACHYCARDIA CHARACTERISTICS VENTRICULAR TACHYCARDIA
- 4. 4 2018 © MediPro Presentation Template www.website.com Ventricular Arrhythmias have three primary types and a few subtypes: (NOTED BY EXCEPTIONS) VENTRICULAR TACHYCARDIA Wide complex greater than 0.12, no P waves, heart rate over 100 bpm. MULTIFOCAL VENTRICULAR TACHYCARDIA / POLYMORPHIC VENTRICULAR TACHYCARDIA Same as above, except with multiple QRS morphologies present TORSADES DE POINTES A form of Polymorphic Vtach, with a defined alternating deflection pattern IDIOVENTRICULAR RHYTHM QRS greater than 0.12, no P waves, heart rate between 20 bpm and 40 bpm ACCELERATED IDIOVENTRICULAR RHYTHM Same as above, with a heart rate between 40 bpm and 100 bpm VENTRICULAR FIBRILLATION Unorganized electrical activity in ventricles, no effective contractions, LETHAL RHYTHM Unless otherwise stated, assume all other characteristics to be within normal limits. VENTRICULAR ARRHYTHMIA TYPES V E N T R I C U L A R A R R H Y T H M I A S
- 5. 5 2018 © MediPro Presentation Template www.website.com PVC’S Premature Ventricular Contractions Wide complex premature beats with no P wave, usually followed by a compensation pause. Ventricular Couplets, Triplets, Runs. Multiple PVC’s occurring in sequence. Four to Ten beats in sequence is considered a Run. Ventricular Bigeminy, Trigeminy, Quadrigeminy PVC’s occurring in a pattern or three or more ectopic beats. Bigeminy – every other beat, Trigeminy – every third beat, Quadrigeminy – every fourth beat. Interpolated PVC’s and Fusion Beats Interpolated PVC’s fall directly between two normal beats with no compensation pause. Fusion beats fall directly where the normal beat would fall and replaces it. Frequently confused with aberrantly conducted Sinus MOST COMMON VENTRICULAR ECTOPY V E N T R I C U L A R A R R H Y T H M I A S
- 6. 6 2018 © MediPro Presentation Template www.website.com R on T Phenomenon occurs when the QRS of a PVC falls directly on top of the T wave from the preceding normal beat. This is a volatile situation and can quickly degrade into Ventricular Tachycardia, Ventricular Fibrillation, or Torsades. Bundle Branch Blocks or IVCD is often mistaken for Ventricular rhythms or ectopy. Remember true ventricular rhythms do NOT have P waves. The following abnormalities all cause wide QRS complexes that are not ventricular in origin: Aberrant Conduction Bundle Branch Blocks and IVCD Junctional rhythms Pacer rhythms R ON T PHENOMENON AND COMMONLY MISSED IDENTIFICATIONS V E N T R I C U L A R A R R H Y T H M I A S
- 7. 7 2018 © MediPro Presentation Template www.website.com Asystole is the complete absence of all electrical activity, resulting in a flat , usually wavy line. A patient in asystole is in full cardiac arrest and requires immediate CPR. Pulseless electrical activity may appear to be organized heart rhythm, however the impulse is not strong enough to induce full contractions, and therefore has no cardiac output. PEA is treated the same as Asystole. Agonal rhythms are also considered cardiac arrest, and usually are identified by an occasional, erratic, ventricular contraction with no rhythm and less than 20 bpm. ASYSTOLE AND PEA V E N T R I C U L A R A R R H Y T H M I A S To Shock or Not To Shock When to Defibrillate Defibrillation, or treatment of cardiac arrest with electric shock, can only convert electrical activity within the heart, not create it. Therefore, only Ventricular Fibrillation is treated with full defibrillation. Asystole, PEA, and Agonal rhythms are treated with CPR and medication.
- 8. 8 2018 © MediPro Presentation Template www.website.com Signals from the SA node are intermittently blocked from entering the ventricles. 2nd Degree HB 3rd Degree HB Signals from the SA node are completely blocked from entering the ventricles. As such, the atrial contractions and ventricular contractions are completely unrelated to each other. While this is a form of complete AV dissociation, 3rd degree blocks require a faster atrial rate than ventricular rates. Signals from the SA node are delayed in passing through to the ventricles 1st Degree HB ATRIOVENTRICULAR HEARTBLOCKS A V B L O C K S AV BLOCKS have several varieties, listed by degrees, and largely based on P waves. FIRST DEGREE AV BLOCK – PR interval greater than 0.20 SECOND DEGREE AV BLOCK TYPE I – aka Wenkebach, steadily increasing or decreasing PR interval, followed by a dropped QRS complex. Usually has elongated PR intervals. SECOND DEGREE AV BLOCK TYPE II – aka Mobitz II, constant PR interval followed by a dropped QRS complex. May drop multiple beats in sequence. PR usually less than 0.20. THIRD DEGREE AV BLOCK – aka Complete Heart Block, R-R is regular, P-P interval is regular, but the PR interval is completely erratic. Heart rate is often very slow, P waves can be found in unusual places. This is a critical finding and requires emergent care.
- 9. 9 2018 © MediPro Presentation Template www.website.com Occurs when the P waves have no association with the QRS complexes, yet the rhythm does not meet the criteria of a 3rd degree AV block. The atrial rate and ventricular rate are similar, and sometimes the ventricular rate will actually be faster. AV DISSOCIATION Three or more QRS complexes dropped in sequence, in the presence of a Second degree AV block. HIGH GRADE AV BLOCK Isolated occurrences of multiple Atrial impulses being blocked in sequence. Must include 4 or more P waves with no QRS. VENTRICULAR STANDSTILL OTHER FORMS OF DISSOCIATION A V B L O C K S FACT: Atrial Flutter is actually a form of AV dissociation. It is differentiated due to its excessively high atrial rate. Atrial contractions occur right at the end of the previous atrial contraction.
- 10. 10 2018 © MediPro Presentation Template www.website.com EXTENTED PR INTERVAL Greater than 0.201ST Degree STEADILY CHANGING PR INTERVAL Followed by a dropped heartbeat.2nd Degree Type I CONSTANT PR INTERVAL Followed by a dropped heartbeat2nd Degree Type II COMPLETE AV DISSOCIATION Constant P-P Interval, Constant R-R Interval, Variable PR3rd Degree AV NODAL BLOCKS A V N O D E A R R H Y T H M I A S *NOTE* AV Blocks and SA Blocks are similar: The difference is whether or not the SA node signal is stopped at the Sinoatrial region or if it is stopped at the Atrioventricular region. This is evidenced by NO P wave at drops in SA Block, while a nonconducted P wave will be present at drops in AV Blocks.