ECG Module
The patient is an elderly man who presented to the emergency ward with dizziness  Rate – 42 bpm Normal Sinus Rhythm L axis...
Hyperkalemia (K 7.6) secondary to acute renal failure <ul><li>The earliest change (usu K>5.7) is a tall, peaked, most ofte...
This 10-second rhythm shows at least three different rhythms! Can you find them?    Atrial Flutter Sinus Beat Atrial Fibri...
Atrial Flutter <ul><li>Atrial rate is usu 250 to 350 bpm, but can be reduced to 200 bpm with antiarrhythmic drugs </li></u...
Atrial Fibrillation <ul><li>Arrhythmia is characterized by wavelets propogating in different directions  </li></ul><ul><ul...
Regular, Rate 93 bpm Normal Sinus Rhythm  R atrial enlargement # 2
 
Regular Ventricular Rate 90 bpm Atrial Rate 180 bpm
Ventricular Rate 180 bpm
85-year-old patient with valvular heart disease and congestive heart failure.  #18 Regular, Rate 88 bpm P-wave downward in...
Atrial Tachycardia <ul><li>AT is a regular, atrial rate >100 bpm originating outside the sinus node </li></ul><ul><ul><li>...
51-year-old female with palpitations.  # 5 Regular Rate 142 bpm No clear P waves before QRS – Not sinus rhythm Retrograde ...
Resting ECG in a 65 year-old male with complaint of palpitations.  Regular Rate 150 bpm No clear P waves before QRS – Not ...
Mechanism of Reentry An impulse initiated in the SA node passes through both the AV node and the accessory pathway A prema...
Mechanisms of Supraventricular Tachycardia AVNRT – the AV node is divided into two pathways and the activation of the atri...
Regular Rate 166 bpm   No clear P waves before QRS – Not sinus rhythm Wide QRS  160 ms RBBB pattern DDx of regular wide co...
A question of aberrancy <ul><li>Occurs when a supraventricular impulse encounters persistant refractoriness in part of the...
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Regular, Ventricular Rate 150 bpm Wide QRS complex 180 ms <ul><li>V. Tach </li></ul><ul><li>SVT w/ aberrant conduction or ...
Ventricular Tachycardia <ul><li>VT consists of at least three consecutive QRS complexes originating from the ventricles an...
RBBB Missed Beat – not sinus rhythm 12
 
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AV block <ul><li>Delay or interruption in the transmission of an impulse from the atria to the ventricles due to an anatom...
Wenckebach: Mobitz type 1 <ul><li>Almost always involves the AV node </li></ul><ul><li>Marked by gradual lengthening of th...
LBBB Non conducting beat 13
Atrial rate 88 bpm Ventricular rate 50 bpm
Complete Heart Block <ul><li>Always produces AV disassociation </li></ul><ul><ul><li>Independent atrial and ventricular ra...
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EKG Module

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EKG Module

  1. 1. ECG Module
  2. 2. The patient is an elderly man who presented to the emergency ward with dizziness Rate – 42 bpm Normal Sinus Rhythm L axis deviation PR prolongation Widened QRS Peaked T waves #16
  3. 3. Hyperkalemia (K 7.6) secondary to acute renal failure <ul><li>The earliest change (usu K>5.7) is a tall, peaked, most often symmetrical (tented) T wave with a narrow base </li></ul><ul><ul><li>Best seen in II,III, V2-4 </li></ul></ul><ul><ul><li>QRS complex may resemble RBBB, LBBB, LAFB, LPFB </li></ul></ul><ul><li>Normal or decreased QTC </li></ul><ul><li>QRS complex widens uniformly a level of 9 to 11 mEq/L </li></ul><ul><li>Reduction in P-wave amplitude and PR prolongation occurs K>7 </li></ul><ul><ul><li>At K>9 the P-wave becomes unrecognizable </li></ul></ul><ul><li>SA and AV block as well as jxnal and escape rhythms can also be seen. </li></ul>
  4. 4. This 10-second rhythm shows at least three different rhythms! Can you find them?  Atrial Flutter Sinus Beat Atrial Fibrillation
  5. 5. Atrial Flutter <ul><li>Atrial rate is usu 250 to 350 bpm, but can be reduced to 200 bpm with antiarrhythmic drugs </li></ul><ul><li>Ventricular Rate – usually half the atrial rate </li></ul><ul><ul><li>Significantly slower ventricular rate suggest AV nodal blockade or disease </li></ul></ul><ul><li>ECG reveals regular sawtooth flutter waves best visualized in II,III, AVf, or V1 </li></ul><ul><ul><li>Inverted flutter waves in II and III are found in typical, type 1 flutter due to counterclockwise re-entrant pathway </li></ul></ul><ul><li>Usually a regular rhythm except if there is variable block </li></ul><ul><li>Flutter tends to be unstable and usually will revert to sinus rhythm or degenerating into atrial fibrillation </li></ul>
  6. 6. Atrial Fibrillation <ul><li>Arrhythmia is characterized by wavelets propogating in different directions </li></ul><ul><ul><li>This caused disorganized atrial depolarization without effective atrial contraction </li></ul></ul><ul><li>On ECG, there are small irregular undulations of variable amplitudes called f waves </li></ul><ul><ul><li>Range from rates btw 350 and 600 bpm and commonly undetectable on surface ecg </li></ul></ul><ul><ul><li>Represent multiple wavelets of depolarization generating larger vectors </li></ul></ul><ul><li>Ventricular response is grossly irregular and usu btw 100 and 160 bpm </li></ul><ul><ul><li>When ventricular rate is very rapid the rate may appear to be more regular </li></ul></ul>
  7. 7. Regular, Rate 93 bpm Normal Sinus Rhythm R atrial enlargement # 2
  8. 9. Regular Ventricular Rate 90 bpm Atrial Rate 180 bpm
  9. 10. Ventricular Rate 180 bpm
  10. 11. 85-year-old patient with valvular heart disease and congestive heart failure. #18 Regular, Rate 88 bpm P-wave downward in II, Not Sinus Rhythm Atrial rate – 220 with 2:1 AV block
  11. 12. Atrial Tachycardia <ul><li>AT is a regular, atrial rate >100 bpm originating outside the sinus node </li></ul><ul><ul><li>Arise from a single site in contrast to </li></ul></ul><ul><ul><li>A. fib or flutter which involve multiple </li></ul></ul><ul><ul><li>sites or circuits </li></ul></ul><ul><li>Arise from </li></ul><ul><ul><li>Increased automaticity – </li></ul></ul><ul><ul><li>acceleration of a nl automatic pacemaker </li></ul></ul><ul><ul><li>Triggered activity – focal electrical events that are called afterdepolarizations </li></ul></ul><ul><ul><li>Microreentry – in which slow conduction allows for allowing to regain it ability to become excitability forming a reentrant circuit </li></ul></ul><ul><li>Atrial rate usu bte 130 – 250 </li></ul><ul><ul><li>P wave morphology can be similar or different to sinus P-wave depending on the origin of the pacemaker </li></ul></ul><ul><li>Usu AV conduction is 1:1, but 2:1 block can occur if atrial rate>200 and/or with significant AV nodal disease </li></ul>
  12. 13. 51-year-old female with palpitations. # 5 Regular Rate 142 bpm No clear P waves before QRS – Not sinus rhythm Retrograde P-waves, with short RP interval
  13. 14. Resting ECG in a 65 year-old male with complaint of palpitations. Regular Rate 150 bpm No clear P waves before QRS – Not sinus rhythm Retrograde P-waves, with short RP interval
  14. 15. Mechanism of Reentry An impulse initiated in the SA node passes through both the AV node and the accessory pathway A premature atrial impulse occurs and reaches the accessory pathway when it is refractory, but conduction occurs through the AV node The impulse takes sufficient time to circulate through the AV node to allow the accessory pathway to recover initiating reentry
  15. 16. Mechanisms of Supraventricular Tachycardia AVNRT – the AV node is divided into two pathways and the activation of the atria and ventricle is synchronous so the retrograde P-wave is buried. Account for 60% of SVT. Usu are 150-200 bpm Orthodromic AVRT – mechanism seen on previous slide. Usually, L atrium is the first site retrograde atrial activation. Accounts for 30% of SVT Widened QRS Antidromic AVRT – activation occurs in the opposite direction resulting in wide complex tachycardia that is indistinguishable from V tach
  16. 17. Regular Rate 166 bpm No clear P waves before QRS – Not sinus rhythm Wide QRS 160 ms RBBB pattern DDx of regular wide complex tachycardia (WCT) <ul><li>V. Tach </li></ul><ul><li>SVT w/ aberrant conduction or preexisting block </li></ul><ul><li>- Sinus tachycardia - A. flutter - AVRT/AVNRT - A. tachycardia </li></ul>Retrograde P-waves associated with the QRS complex PVC 8
  17. 18. A question of aberrancy <ul><li>Occurs when a supraventricular impulse encounters persistant refractoriness in part of the ventricular conduction system </li></ul><ul><ul><li>Refractory period RR interval </li></ul></ul><ul><li>Aberration can result from a shortened RR interval and refractory period (1) or a lengthened RR interval and refractory period (2) </li></ul><ul><li>Always initially assume wide QRS is ventricular </li></ul><ul><ul><li>80% of WCT are VT </li></ul></ul><ul><li>Triphasic rsR’ in V1 and qR in V6 favor aberrancy </li></ul><ul><li>If the QRS morphology is similar to sinus rhythm, then WCT unlikely ventricular in origin </li></ul>1 2
  18. 19. 7
  19. 20. Regular, Ventricular Rate 150 bpm Wide QRS complex 180 ms <ul><li>V. Tach </li></ul><ul><li>SVT w/ aberrant conduction or preexisting block </li></ul><ul><li>- Sinus tachycardia - A. flutter - AVRT/AVNRT - A. tachycardia </li></ul>DDx of regular wide complex tachycardia (WCT) 15
  20. 21. Ventricular Tachycardia <ul><li>VT consists of at least three consecutive QRS complexes originating from the ventricles and recurring at a rapid rate (>120 bpm) </li></ul><ul><li>As a consequence of ischemic heart disease </li></ul><ul><ul><li>May appear almost immediately after prox obstruction of a major coronary artery – tends to be unstable VT that can degenerate into Vfib </li></ul></ul><ul><ul><li>Weeks to months after an MI – more stable VT can occur </li></ul></ul><ul><li>Other – nonischemic cardiomyopathy (idiopathic dilated, HOCM), RV outflow tract, medications </li></ul><ul><li>Distinguishing btw VT and SVT with aberrant conduction </li></ul><ul><ul><li>AV dissociation </li></ul></ul><ul><ul><li>Fusion and Capture beats </li></ul></ul><ul><ul><li>No RS pattern in any of the precordial leads suggests VT </li></ul></ul><ul><ul><li>Biphasic Rsr or monophasic R waves are suggestive of VT </li></ul></ul><ul><li>Sustained VT is defined if it lasts for >30 seconds or more than 10 beats </li></ul>
  21. 22. RBBB Missed Beat – not sinus rhythm 12
  22. 24. 12
  23. 25. AV block <ul><li>Delay or interruption in the transmission of an impulse from the atria to the ventricles due to an anatomical or functional impairment in the conduction system. </li></ul><ul><li>Etiology </li></ul><ul><ul><li>Idiopathic progressive cardiac conduction disease (rare) </li></ul></ul><ul><ul><li>Ischemic heart disease (approx 40%) </li></ul></ul><ul><ul><li>Drugs </li></ul></ul><ul><ul><li>Increased vagal tone </li></ul></ul><ul><ul><li>Valvular disease – calcification of aortic and mitral valve </li></ul></ul><ul><ul><li>Infection – Lyme disease, toxoplasmosis, endocarditis, syphilis diphthiria, rheumatic fever </li></ul></ul><ul><ul><li>Infitrative process – sarcoidosis, amyloid </li></ul></ul><ul><ul><li>Inflammatory – SLE, rheumatoid </li></ul></ul><ul><ul><li>Hyperkalemia </li></ul></ul>
  24. 26. Wenckebach: Mobitz type 1 <ul><li>Almost always involves the AV node </li></ul><ul><li>Marked by gradual lengthening of the PR interval and a gradual shortening of the RR interval and an eventual dropped beat </li></ul><ul><ul><li>The first PR interval of the second cycle will invariably be shorter than the last PR interval of the preceding cycle </li></ul></ul><ul><li>Progressive PR interval occurs because each atrial impulse arrives progressively earlier in the refractory period of the AV node </li></ul><ul><ul><li>This it takes progressively longer to penetrate the node and reach the ventricles </li></ul></ul><ul><li>Maximal increase in the PR interval happens btw the first and second cycle, and the increase becomes successively smaller in subsequent cycles </li></ul><ul><ul><li>This leads to progressively shortening of the RR interval </li></ul></ul>
  25. 27. LBBB Non conducting beat 13
  26. 28. Atrial rate 88 bpm Ventricular rate 50 bpm
  27. 29. Complete Heart Block <ul><li>Always produces AV disassociation </li></ul><ul><ul><li>Independent atrial and ventricular rate </li></ul></ul><ul><ul><li>But AV disassociation can be caused by </li></ul></ul><ul><ul><ul><li>Decreased sinus automaticty, junctional or ventricular escape, ventricular tachycardia which make the AV node refractory so the sinus impulse cannot traverse the AV node </li></ul></ul></ul><ul><li>If the sinus rate < ventricular rate then one must consider that a junctional or ventricular pacemaker has taken over </li></ul><ul><li>If the sinus rate > ventricular rate, then complete heart block becomes apparent, as both the atrial and ventricular complexes maintain independent rhythms </li></ul>
  28. 30. 2
  29. 32. 6

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