Clinical Skills - EKG Guide By Izzy Pines Basics on Waveforms: P wave: 1 st deflection. Represents atrial depolarization PR interval: Represents conduction through the AV node QRS complex: Represents ventricular depolarization and contraction ST segment: Represents interval between depolarization and repolarization QT interval: Represents the entirety of ventricular activity T wave: Represents ventricular repolarization U wave: Rarely seen on EKG. Represents recovery of the Purkinje conduction fibers Learn to Read EKGs Systematically: Method 1: AHI AHI r A te r H ythm I ntervals A xis H ypertrophy I schemia Method 2: Rules of 4’s A. 4 initial features 1. History 2. Rate 3. Rhythm 4. Axis B. 4 wave forms 1. P wave 2. QRS complex 3. T wave 4. U wave C. 4 intervals/segments 1. PR interval 1
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Clinical Skills - EKG GuideBy Izzy Pines
Basics on Waveforms:
P wave: 1st deflection. Represents atrial depolarizationPR interval: Represents conduction through the AV nodeQRS complex: Represents ventricular depolarization and contractionST segment: Represents interval between depolarization and repolarizationQT interval: Represents the entirety of ventricular activityT wave: Represents ventricular repolarizationU wave: Rarely seen on EKG. Represents recovery of the Purkinje conduction fibers
Learn to Read EKGs Systematically:
Method 1: AHI AHI
rAterHythm Intervals
Axis Hypertrophy Ischemia
Method 2: Rules of 4’s
A. 4 initial features1. History2. Rate3. Rhythm4. Axis
B. 4 wave forms1. P wave2. QRS complex3. T wave4. U wave
C. 4 intervals/segments1. PR interval2. QRS width3. ST segment4. QT length
1
What are you looking for? Rate : 60-100 bpm
o Use the dark lines (big boxes) to count 300, 150, 100, 75, 60, 50, 42 (bpm)o Count number of QRS on strip in 6 second interval and multiply by 10o Divide 300 by the number of QRS complexes present
Rhythm: Is it sinus?o Sinus = P before every QRS, QRS after every Po Other options = irregular, junctional, ventricular, ectopic beats
Axis: Normal, left axis deviation, right axis deviation?o Normal = Upright QRS complexes in leads I, II, and aVFo Left axis deviation = upright QRS in lead I, downward QRS in aVFo Right axis deviation = upright QRS in aVF, downward QRS in lead I
P waveo Check lead II for p wave pathology because they’re most prominento Duration <120ms (<3 small boxes)o Amplitude <2.5mm (2.5 small boxes) o Do they occur regularly? – march them outo Are the P-Waves smooth, rounded, and upright?o Do all P-Waves have similar shapes?o Note: biphasic P wave in V1 is normalo Abnormalities:
Peaked P waves (>2.5mm tall) (P pulmonale) = right atrial enlargement (likely d/t pulm HTN)
Notched P waves (P mitrale) = left atrial enlargement (likely d/t mitral stenosis) Inverted P waves = ectopic atrial rhythm Variable P waves = multifocal atrial rhythms
PR intervalo Duration = 120-200ms (<1 big box)o Is the PR Interval constant across the ECG tracing?o Abnormalities
Consistently > 200ms (NO dropped QRS’s) = 1st degree AV block Progressive increase in PR interval then dropped QRS = 2nd degree AV block Type 1 Constant PR interval then dropped QRS = 2nd degree AV block Type 2 PR interval < 120ms = Junctional rhythm, Wolff-Parkinson-White syndrome or Lown-
2nd Degree AV Block, Mobitz Type 1 (Wenckebach)Image source
2nd Degree AV Block, Mobitz Type 2Image source
3rd Degree AV Block (complete heart block)Image source
Above: Type A WPW Syndrome (dominant R in V1 = left sided accessory pathway)Type B WPW Syndrome (dominant S in V1 = right sided accessory pathway)Image source
myocardial dz, rotation of heart, lead placement errors) > 40 ms (1 small box) wide > 2 mm (2 small boxes) deep > 25% of depth of QRS complex Seen in leads V1-3
> 120ms = Bundle branch block RBBB (rabbit ears) = RSR’ in V1 and V2 LBBB = broad notched R in V5, V6, I, and aVL, reciprocal changes in V1-2
Normal q wave in V6 Pathologic q waves in II, III, avFImage source Image source
< 350ms = hypercalcemia, digoxin, congenital short QT syndrome T wave
o Amplitude < 5 small boxes in limb leadso Should be upright in all leads except aVR and V1o Abnormalities:
Peaked (almost as tall as QRS) = hyperkalemia Upright T wave in V1 = acute ischemia (if new) otherwise CAD Inverted = normal in kids, MI, LBBB & LVH (in I, aVL, V5-6), RBBB (in V1-3),
RVH & PE (in V1-3, and II, III, aVF), HCM (V1-6), increased ICP Biphasic = hypokalemia (down then up), MI (up then down) Flattened = electrolyte abnormality (if generalized), MI (if in contiguous leads)