EKG

  • How to read EKG and what to read:
  1. 1st look at AVR  lead : All waves are inverted ( all p wave, qrs complex and T wave), if it is not inverted then EKG is not right
  2. now calculate Heart rate ---increased or decreased?? 
  3. also check rhythm? regular or irregular?? 
  4. Now see Pwave morphology in lead 2
  5. next is PR interval in lead 2: noraml is 3 to 5 mm or around 3 to 4 small sq
  6. next is QRS complex in lead 1 and 3: look for axis deviation, normal is 2-2.5mm or < 3 small sq and qwave < 1small sq or <1/3 of R wave
  7. look at chest leads now : mainly qrs pattern
  8. ST segment: depressed or elevated
  9. Twave:  Flat/ inverted/tall
I found this nice algorithm.....

RHYTHMHEART RATEP WAVEASSOCIATED WITH QRSDISORDERS
RegularSlowYesYes
Sinus Bradycardia
2nd Degree Heart Block
No3rd Degree Heart Block
No 
Idioventricular Rhythm
Hyperkalemia
Persistant Atrial Standstill
NormalYesYes
Normal Sinus Rhythm
2nd Degree Heart Block
NoVentricular Tachycardia
No 
Idioventricular Rhythm
Hyperkalemia
Persistant Atrial Standstill
Atrial Flutter
FastYesYes
Sinus Tachycardia
Supraventricular Tachycardia
No
Ventricular Tachycardia
Non-paroxysmal Junctional Tachycardia
No Atrial Flutter
IrregularSlowYesYes
Sinus Bradycardia
Sinus Arrhythmia
Sick Sinus Syndrome
2nd Degree Heart Block
NoIdioventricular Rhythm (rhythm is usually regular)
No Slow Atrial Fibrillation
NormalYesYes
Sinus Arrhythmia
2nd Degree Heart Block
NoVentricular Tachycardia (rhythm is usually regular)
No 
Atrial Fibrillation
Atrial Flutter
FastYesYes
Sinus Tachycardia
Supraventricular Tachycardia
No
Ventricular Tachycardia (rhythm is usually regular)
Non-paroxysmal Junctional Tachycardia
No 
Atrial Fibrillation
Atrial Flutter

Approach to the ECG to assess dysrhythmias.



  1. Determine the ventricular rate - note paper speed.
  2. Determine the atrial rate - note paper speed.
  3. Are P and QRS associated?
    • same rate
    • reasonable PR interval
    • consistent PR interval
  4. Determine PR interval - note paper speed
    • does it vary?
  5. Are there any P waves that are not followed by a QRS complex?
  6. Are there any QRS complexes with no P waves?
  7. Determine the width of the QRS complexes - note paper speed.
  8. Is the rhythm regular or irregular?
  9. Any premature beats? - note morphology and duration
  10. Are the P waves positive in lead II?
  11. Are the QRS complexes of normal morphology?

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Common EKG findings:
http://www.skillstat.com/ecg_sim_demo.html

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  • Heart Rate Calculation:  1500/ small sq between two R waves or 300/big sq between two R waves.
  • when irregular HR then count R waves in 5 big sq (1 big sq = 0.2 sec so 5big sq=1 min)
  • Normally there are 15 to 20 small sq between 2 R waves..
  • RA hypertrophy:  Tall P wave also k/s P pulmonale
  

  • LA hypertrophy : Notched/ wide P wave , also K/s P mitrale

  • both atrial Hypertrophy: Pwave will be > 2.5 small sq taller and wider..
  • Axis Deviation: Check qrs wave in lead 1 and 3
LAD: left leaves
RAD: Rt reaches
  • Left ventricular Hypertrophy:  increase in amplitude of qRs complex wave in V1-6 but normal progression
  • Right ventricular hypertrophy: increase in amplitude of QRS complex but reversal of pattern
  • Strain pattern:
With LVH: Tall R waves in v5 and V6 + depressed ST segments and inverted T wave  reduced in amplitude..
With RVH: in MS, Tall R waves in V1 and V2 + depressed ST segments and inverted T wave  reduced in amplitude
  • Biventricular hypertrophy:  increase in amplitude of R wave in V1 + S wave in v2 and v1 + increase in amplitude of R wave in V5 and V6 .
  • Arrythmia:
Disorder in impulse production:
  1. brady/Tachy
  2. Flutter
  3. Fibrillation
  4. Abnormal sinus rythm
  5. premature beats
DIsorder in Impulse conduction:

  1. Heart block
  2. WPW syndrome
  3. bundle branch block
  • Premature Beat/ extrasystole/ ectopic beat: arise from other then SA node
If it is from Atria: then compensatory pause is incomplete but if it arise from Ventricle then compensatory pause is complete

  1. Supraventricular: Abnormal P wave but normal QRS complex. Lesser is the PR interval, Closer is the loci towards AV node. 
  2. Nodal: inverted or absent P wave 
  3. Ventricular: Absent P wave with bizarre, slurred and wide QRS complex + inverted T wave
  • Sinus Pause:  after pause there is Normal P wave and QRS complex and T wave but  ....While in Ectopic beat abnormal pause occurs K/s Compensatory pause where abnormal P/qrs is f/b pause
>1.5 sec: Sinus arrest and next beat from other pacemakers k/s Escape beat

1.5 to 1.6 sec: from ATria
1.7: nodal/junctional
1.8 to 2.2 sec: ventricular


  • Interpolated Ventricular Premature beat: Does not have any effect on sinus rhythm, means no pause but increase in PR interval of succeeding beat. Usually seen in bradycardia
  • Ventricular Bigemini: when every alternate beat is VPB.
  • Multifocal VPBS: when contour of VPB is different.
 

See in above ECG 3rd beat and 7th beat is premature beat(coz wide slurred QRS complex and T wave) but contour is different in both....

So in summary for premautre/ ectopic beat check both precceding and succeeding beats' P, QRS , T contour and PR interval... + contour of Premature beat


  • Sinus Arrhythmia: INspiration-------------> Increase, Expiration-------------> decrease in Heart rate but normal PR interval and Normal P, QRS complex
  • Sinus Bradycardia: Normal PR interval but increase R-R interval
  • Sinus Tachycardia: Normal PR interval but decrease R-R interval
  • Atria Rhythm: whuch includes
  1. Wandering pacemaker: Noramal QRS complex but contour of P wave is different so the PR interval
  2. ATrial Rhythm: Pwave contour and PR interval is abnormal(decreased) but constant in all beats.
  3. SVT: rate is usually 180 to 220 per min. While in sinus tachy is usually 120 to 180
  4. Atrial Flutter: Instead of P wave, there is F wave which is large, wide and multiple...Always acc/b AV block and slower ventricular Rate
  5. AF: p wave is not seen but Base line is finely irregular...and QRS comples comes at irregular interval....f satnds for irregular fibrillation wave which may be fine, medium or coarse(flutter-fibrillation)..each f wave occupies < 4 small sq..so atrial rate wud be >400---which is beyond A.flutter

See in this ECG contour of P wave is different: In 2nd beat , it is elevated while in 3rd beat it is inverted and so the PR interval. Showing Wandering Pacemaker...


In above ECG P wave in lead 2 is inverted which is not normal.....but it's constant and so th e PR interval....so this is Atrial Rhythm..and obviusly pacemaker is somehere in lower in Atrium...

  • SVT:

Here HR= 1500/8= 187 ----------So its not sinus tachy...but SVT
here u can see P wave easily....


Here U cant see P wave but noraml QRS complex ...HR= 1500/7=214----------so SVT

Around 200 HR -------you wont be able to diff P and T wave....

  • Atrial FLutter: each F wave occupies one large sq...

  • Atrial fibrillation: see irregular baseline, qrs at irregular interval...and absent p wave...