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Definition of NSR:
Rate 60-100
Rhythm Regular
P normal
PR .12-.2
QRS .04-12
Sinus Arrhythmia - NSR + Irregular R-R

Note for the week of February 19, 2012 Dubin 264-266
Wellen Syndrome
In adults flat (nonexistent) T waves or minimal T wave inversion may be a normal variant in any of the limb leads (frontal plane). However, any T wave inversion in leads V2 through V6 is considered pathological. Marked T wave inversion in leads V2 and V3 are the hallmarks of Wellens syndrome and altert us to stenosis of the left anterior descending artery. These can also be biphasic T waves in a less common variant.

Ischemia is indicated first by T wave inversion.
Injury is indicated first by ST elevation and is thus an acute indicator.
Angina without exertion is Prinzmetal's and can cause STe without injury.

 Brugada Criteria to determine if rhythm is VT.  Only 1 is required to establish a diagnosis of VT:  
1) The absence of an R-S complex on ALL of the precordial leads (aka "concordance"). Meaning all of the QRS complexes are either all positive or all negative, no in betweens.
2) R-S interval > 100 ms in ANY precordial lead
3) The presence of atrioventricular dissociation (try to identify P waves amongst the QRS complexes going at a different rate, if present then you have AV dissociation and VT is the rhythm)
4) Specific morphology criteria for the QRS complexes.

Ventricular tachycardia (VT) occurs when multiple ectopic ventricular beats occur in succession. If all of the QRS complexes appear the same or very similar, then it is termed monomorphic VT. If the QRS complexes appear different from beat-to-beat, then it is termed polymorphic. Another name for polymorphic VT is "Torsades de Pointes".  VT can be hemodynamically unstable resulting in syncope and can degenerate into the universally fatal rhythm ventricular fibrillation.

When describing ventricular tachycardia, the following should be mentioned:

1) Monomorphic versus polymorphic (Torsades)
2) Sustained versus non-sustained (sustained defined as > 30 seconds in duration or symptomatic)
3) The heart rate at which it is occurring (electrophysiologist use the "cycle length" or the number of milliseconds between the QRS complexes)

1. Sinus Bradycardia
2. Sick Sinus Syndrome
3. Sinus Tachycardia
4. Wandering atrial pacemaker
5. NSR with PACs
6. MAT
7. NSR with PVCs
8. Afib
9. Aflutter
11. PSVT
12. Junctional Escape Rhythm (40 - 60 bpm)
13. Accelerated Junctional Rhythnm (60 - 100 bpm)
14. Juctional Tachycardia (100 - 180 bpm)
15. SVT
16. VTac
17. SVT with aberrancy (how distinguish from VTac ?)
18. Vfib
19. 1st degree AV block
20. 2nd degree AV block type I
21. Wenckeback type I
22. 2nd degree AV block type II
23. 3rd degree AV block


This Detailed Algorithm is included for historical purposes only - my algorithm prior to M.B.'s class.

(s) - small
(l) - large

1. Rate
2. Rhythm / Regularity / Irregularity  ans: NSR or Sinus Arrhythmia or Arrhythmia 
--1. Look at R-R distance (occasionally irregular, regularly irregular, irregularly irregular)
--2. Is there a  P b4 each QRS and a QRS after every P ? ans: Nl P waves w/ 1 P wave for q QRS
3. Interval
--1. is PR > .2 ? - If so, block types: (1-avb=pause, 2-Wen lengthening PR Mob random drops, 3-block)
--2. is AV in range of  0.10 - 0.12 - ICBBB, AV > 0.12 BBB 
-- LBBB QRS V5V6 R_|~|_R' 
----- absent Qs in I, AVL
----- positive R in I, aVL, V6
----- V6 large, wide
----- Repolarization abnormalities with ST and T vectors directed opposite the QRS
-- RBBB QRS V1V2 R|\/|R'  
----- s Q and l R in I
----- s + R and s - S in V6
----- STd & Ti in rt precordial leads 
----- upright T waves in l precordial & limb leads
--3. QT Long ? (>1/2R-R) 450 ms is probably criteria for long QT. Read this
--4. Axis Deviation (Hemiblocks) AH-LAD-small Q in I, small R in III, PH-RAD- small R in I, small Q in III
      For pathologic LAD, if I is positive and AVF negative, then II must be net negative and the angle will be greater than - 30.
4. Axis 
--Frontal (Quadrant, Degrees - Deviation)
--Horizontal (Chest, Transition Point - Rotation)
5. Hypertrophy  
-- 1. R atrium - peaked P in V1
-- 2. R Ventricle -  R in V1
-- 3. L atrium - expect diphasic P in V1
-- 4. L Ventricle -  SV1 RV5
-- 5. L Ventricle -  Cornell Criteria - SV3 + RAVL > 28 men, > 20 women.
5. Infarction - Q, inverted T, ST elevation/ depression.



Important Notes to always consider: Example of a normal EKG

.01 The P wave should be upright in lead II if the action potential is originating from the SA node. If there are P waves in lead II that are not upright (either inverted or biphasic), then an ectopic atrial rhythm is present. If no P waves are seen, then either a junctional rhythm (regular QRS complexes) or atrial fibrillation (irregularly irregular QRS complexes) is present.
.02 T waves should be upright in most leads (except aVR and V1). 
.03 If the T wave appears symmetric, cardiac pathology may be present.
.04 QT interval: The time from the beginning of the QRS complex (ventricular depolarization) to the end of the T wave (ventricular repolarization).
.05 ST segment: The portion of the ECG from the end of the QRS complex to the beginning of the ECG. 
.06 TP segment: The portion of the ECG from the end of the T wave to the beginning of the P wave. This segment should always be at baseline and is used as a reference to see if the ST segment is elevated or depressed.
.07 If there is a P wave before every QRS complex, the P wave is upright in lead II, and the P wave has a normal morphology, then normal sinus rhythm is said to be present.
.08 Failure of R wave progression - 
.09 Q waves indicate old infarctions.
.10 PR segment depression indicates 
.11 Sgarbossa ST changes indicate 
.12 Delta waves indicate 
.13 Osborne waves indicate 
.14 Epsilon waves indicate

1.   ST elevation DDX - acute injury (MI), aneurysm, brugada, early repolarization, pericarditis, prinzmetal's angina (variant, unstable angina at rest) (AABEPP)
       - 1.5 Septal wall infarction - ST elevation in V1-V3
       - 1.6 Lateral wall infarction - ST elevation in V4-V6
2.   ST depression DDX - digitalis, hyperkalemia, ischemia, positive stress test (stable angina), posterior infarct, (DHIPP)
       - 2.5 Note Posterior infarct associated with ST depression in V1, V2
3.   Strain pattern - ST becomes depressed & humped (RV in V1, LV in V5). Strain causes hypertrophy.
4.   Failure of R wave progression in V1-V6 DDX: (ACDOH) anterior infarct, COPD, Dextrocardia, Obesity, Hypothyroidism
5.   non-STEMI - STd and/or Ti w/o Q waves - is indistinguishable from unstable angina
6.   Earliest change associated with STEMI - hyperacute or tall, peaked T waves
7.   Unstable angina is not associated with elevated cardiac biomarkers.
8.  "Masquerading RBBB" - http://chestjournal.chestpubs.org/content/55/4/306
9.   A posterior infarction will demonstrate large RV1&RV2 with ST depressions - the opposite of an anterior infarct.
10. P wave marches through in AV block.
11. Intraventricular conduction block - with PACs the P waves don't march through.
12. Always note low voltage. Causes - 
13. QV1V2 - septal infarct
14. Ectopic focus has a single focus and therefore uniform Q waves.
15. MAT has multiple foci and therefore non-uniform Q waves.
16. Biphasic P and deep T waves seen in left atrial enlargement.
17. What is the DDX for LAD ? LVH, Horizontal Heart or Inferior Infarction - must R/O these before DX Anterior (or any) Hemiblock p.297 Dubin
18. No P' then R/O MAT in SVT
19. Ti differential: contusion, dig toxicity, MI, myocarditis (ex. Freidrich's ataxia), old pericarditis, Wellens Ti in V2, V3 - stenosis of anterior descending
      If you know the foregoing you have the basics in hand. If you're an EKG wiz, read the attached paper on HIS Bundle Electrocardiograms and let me know what you think.  - Marc marc@carestandard.com - and on we go ...
20. prolonged PR, scooped ST, shortened QT, T-wave inversion - Digitalis toxicity
21. "long RP think" - atrial tachycardia.  If atrial tachycardia with block think digitalis. PR may be slightly longer than usual. Watch for hypokalemia.
21.5  Atrioventricular nodal reentrant tachycadia - "short RP tachycardia" - think atrial activation occurs rapidly after the QRS complex (within the ST segment) 
21.6 Atrioventricular re-entrant tachycardia - (caused by Wolff-Parkinson-White syndrome is characterized electrocardiographically by a short PR segment, delta wave, and tachycardia).
22. Exercise electrocardiography is best suited for patients with an intermediate probability of coronary artery disease who can exercise, including patients with less than 1 mm ST-segment depression   or complete right bundle branch block on resting electrocardiogram.
23. Pharmacologic stress myocardial perfusion imaging and dobutamine echocardiography are performed in patients with an intermediate pretest probability of coronary artery disease and an   electronically paced ventricular rhythm or left bundle branch block; exercise stress testing is associated with an increase in false-positive test results in patients with left bundle branch block. These tests are also appropriate in patients who cannot exercise.
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Marc Curvin,
Mar 31, 2012, 11:17 AM
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DUBIN.pdf
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Marc Curvin,
Mar 31, 2012, 11:17 AM
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PowerPointPresentation.htm
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Marc Curvin,
Mar 31, 2012, 11:17 AM
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Marc Curvin,
Mar 31, 2012, 11:17 AM
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