WIDE QRS TACHYCARDIA

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WIDE QRS TACHYCARDIA

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WIDE QRS TACHYCARDIA

  1. 1. Wide QRS Tachycardia MSN PAVAN KUMAR
  2. 2. Wide complex tachycardia Definitions Causes Features for differentiation Diagnostic approach/algorithms
  3. 3. Wide complex tachycardiaDefinition : A rhythm with QRS duration ≥ 120 ms and heart rate > 100/min. Sustained vs non sustained
  4. 4. Wide complex tachycardiaCauses : Regular : 1. Ventricular tachycardia(80% of WCT) 2. Any SVT with aberrancy (2nd MC WCT) 3. Any SVT with BBB 4. Any SVT with delayed conduction d/t drugs and electrolytes a. Class IA,IC ; hyperkalemia. 5. Antidromic AVRT(1-5%) 6. Pacemaker mediated rhythm Irregular : 1. AF with conduction on preexcitation pathway. 2. Any irregular SVT with aberrancy , BBB . 3. VT in the 1st 30 sec , pts on anti arrythmitic drugs – cycle length varibility.
  5. 5. Wide complex tachycardiaFeatures for differentiation :  Pacemaker rhythm(<1% of WCT) 1. History and physical examination 2. ECG: a. Stimulus artefact b. LBBB with left superior axis(if RV apical pacing) , various combinations ( biventricular pacing)
  6. 6. Wide complex tachycardiaFeatures for differentiation : VT vs Preexcited tachycardia •VT – Predominantly negative QRS complexes in V4-V6 – Presence of a QR complex in one or more leads V2-V6 – More QRS complex than P •75% sensitivity & 100% specificity for VT (Stierer et al)
  7. 7. Wide complex tachycardia Features for differentiation : History and physical examination:1. H/o heart disease – previous MI , angina , CHF – have a PPA of 95% for diagnosing VT2. Pts with VT are older than SVT (> 35 yrs)3. SVT-A often have h/o previous episode(>3years)4. Pts with SVT-A are hemodynamically stable.5. Examination for AV dissociation a. Cannon A waves in JVP b. Variable S1 intensity c. Variation in SBP unrelated to respiration.6. Termination of WCT with physical manoeuvres and medications
  8. 8. Wide complex tachycardia Features for differentiation by ECG :1. QRS duration2. QRS axis3. Concordant pattern4. Precordial RS duration.5. Morphological criteria - RBBB , LBBB , ambiguous chest lead pattern6. Q wave presence7. AV dissociation8. Baseline QRS prolongation – QRS duration , QRS configuration.9. aVR changes.10.Lead II R-wave-peak-time (RWPT) criterion .
  9. 9. Wide complex tachycardia1. QRS duration : > 160 ms with LBBB , >140 ms with RBBB - VT Wellens et al . Showed that 69% of VT had QRS duration of >140ms and none of SVT-A showed QRS duration of >140ms. Exceptions: a. Anti arrythmitic drugs non specifically prolong QRS duration. b. Pts with structurally normal heart may have VT with QRS duration of 120-140ms.(<140ms in12% , < 120 ms in 4%) c. QRS duration also depend site of origin of VT , septal VT QRS duration has sensitivity of 70%
  10. 10. Wide complex tachycardia
  11. 11. Wide complex tachycardia2. QRS axis : Frontal plane axis of -90 to +180 --- VT Shift in QRS axis of more than 40 from baseline --- VT(less specific) RBBB with LAD, LBBB with RAD --- VT. LAFB (-30 to -90) , LPFB (+110 to150) and RBBB (normal axis).
  12. 12. Wide complex tachycardia3.Concordant QRS in chest leads: Concordant QRS in chest leads is diagnostic of VT uncommon in SVT-A. Exceptions:  Positive concordance (ventricular activation begins left posteriorly) seen in VT originating in Lt post wall or SVT using a left posterior accessory pathway for AV conduction.  If no additional criteria for WPW are absent don’t consider it because of low incidence(<6%) Specificity of 90%, Sensitivity of 20%
  13. 13. Wide complex tachycardia
  14. 14. Wide complex tachycardia3.Concordant QRS in limb leads : The presence of predominantly negative QRS complexes in leads 1,2,3 is suggestive of VT This is another way to describe right superior axis Similar to RS axis it is considered as highly specific for VT
  15. 15. Wide complex tachycardia4.Pericardial RS duration criteria : If concordant QRS complexes are absent i.e with RS complex onset of R wave to nadir of S wave > 100 ms. Sensitivity – 66% Specificity - 98%
  16. 16. Wide complex tachycardia5.RBBB – V1 : rSr , rSR , rR , rsr patterns consistent with SVT-A R , R>30ms with any negative QRS , qR --- VT This is because right ventricle doesn’t participate in initial QRS Sensitivity – 30-80% Specificity - 84-95%
  17. 17. Wide complex tachycardia5.RBBB – V6 : qRs , Rs , RS with R/S >1 --- SVT –A R , QR , QS , RS with R/S < 1 --- VT Sensitivity – 30-60% Specificity - 80-100%
  18. 18. Wide complex tachycardia5. LBBB – V1,V6: Sensitivity – 100% Sensitivity – 17% Specificity - 89% Specificity - 100%
  19. 19. Wide complex tachycardia5.Ambiguous chest lead pattern: W and M pattern in V1 have been classified as LBBB & RBBB Because they are ambiguous in this way, they are unlikely to represent typical aberration and are highly specific for VT. Sensitivity of 60-80% , specificity of 90-95%.
  20. 20. Wide complex tachycardia6. Q wave presence : Q during WCT --- suggest old MI --- VT most likely. In general pts with post MI VT maintain Q wave during WCT that are present during baseline in the same lead. Exceptions : 1. Pts with DCMP will have Q wave during VT that are not present during baseline. 2. PSEUDO Q wave with retrograde p wave deforming QRS can be seen in SVT-A 3. Preexcited tachycardia with posterior AV connection can have Q wave in inferior leads
  21. 21. Wide complex tachycardia7. AV dissociation : The most specific ECG finding for VT . Clues for AV dissociation: 1. Clinically by cannon A waves , variable intensity of S1 , Variation in SBP unrelated to respiration. 2. AV dissociation 3. AV ratio of less than 1 4. 2:1 VA block(d/t retrograde conduction) 5. Variation in QRS amplitude during WCT 6. Fusion & capture beats 7. Recording separate atrial electro gram (oesophageal/transvenous) 8. Echo (evaluating RA contraction in relation to ventricular)
  22. 22. Wide complex tachycardia7. AV dissociation : V rate = 215/mt A rate = 125/mt A/V =0.58
  23. 23. Wide complex tachycardia7. AV dissociation : VT with retrograde 2:1 VA conduction (seen in 15-20% of VT)
  24. 24. Wide complex tachycardia7. AV dissociation :  Variation in amplitude of QRS during WCT 1. Scalar summation of P wave with QRS 2. Variable ventricular filling in the presence of AVD  Presence of multiple WCT configuration has a sensitivity of 55% for diagnosing VT
  25. 25. Wide complex tachycardia7. AV dissociation :  The QRS complex is prolonged, and the R-R interval is regular except for occasional capture beats (C) that have a normal contour and are slightly premature. Complexes intermediate in contour represent fusion beats (F).  Thus, even though atrial activity is not clearly apparent, atrioventricular dissociation is present during ventricular tachycardia and produces intermittent capture and fusion beats
  26. 26. Wide complex tachycardia7. AV dissociation :
  27. 27. Wide complex tachycardia7. AV dissociation :  Caveats while using AVD: 1. Low sensitivity (20-50%) is d/t fast heart rates , inadequate duration of recording , observer inexperience. 2. 30% of pts , especially VT with low V rate , have 1:1 VA conduction – differentiate by vagal maneuvers , adnosine. 3. AF and VT co exist AVD cannot be diagnosed . Sensitivity – 20-50% Specificity – 98%
  28. 28. Wide complex tachycardia8. Base line QRS prolongation:a. Pt with baseline QRS rhythm and WCT QRS different – VT1. QRS during VT is narrower than baseline rhythm2. Contra lateral BBB in baseline rhythm and during WCT3. AV dissociation4. Rarely other findings may be useful like precordial concordance , north-west axis , monophasic R wave in V1 Pts with BBRT Impulse originates in RBB Travels through LBB Have typical features of LBBB
  29. 29. Wide complex tachycardia9. aVR changes :1. Presence of initial ‘r’ wave in aVR2. Presence of initial ‘r’ or ‘q’ wave of > 40ms duration3. Presence of notch in descending limb of negative onset and predominantly negative QRS4. Vi/Vt ≤ 1 All the above features are indicative of VT Sensitivity – 96.7% Specificity – 99%
  30. 30. Wide complex tachycardia 9. aVR changes : Initial ‘r’ wave in aVR During SVT with aberrancy , initial septal activation and main ventricular activation are directed away from lead aVR  negative QRS complexExceptions :1. Inferior MI- initial r wave (rS complex) during NSR or SVT2. VT originating from base of heart may not have initial r wave
  31. 31. Wide complex tachycardia9. aVR changes :
  32. 32. Wide complex tachycardia 9. aVR changes : Vi/Vt ≤ 1Vi = voltage in the initial 40ms of QRSVt = voltage in the terminal 40ms of QRSIn SVT-A only one portion is bundle branch is blocked --- so the initial portion of QRS is rapid compared to terminal portion.In VT slow muscle to muscle spread of impulse causes slower voltage changes through out QRS complexCan be applied to any leadThe vi/vt was > 1 (signifying supraventricular origin) in 88% tracings with LBBB pattern, in 98% with RBBB pattern, and 90% with nonspecific IVCD.
  33. 33. Wide complex tachycardia9. aVR changes : Vi/Vt ≤ 1
  34. 34. Wide complex tachycardia10. Lead II R-wave-peak-time (RWPT) criterion : Pavas criteria RWPT > or =50 ms at DII is a simple and highly sensitive criterion that discriminates VT from SVT in patients with wide QRS complex tachycardia. Sensitivity and specificity of 97% Heart Rhythm. 2010 Jul;7(7):922-6. Epub 2010 Mar 4.
  35. 35. Wide complex tachycardia Diagnostic approach/algorithms 1. Wellens(1978) , Akhtar(1988) , 2. Brugada(1991) 3. Griffith(1994) 4. Bayesian(1995) 5. aVR algorithms(2007) 6. lead II R-wave-peak-time (RWPT) criterion(2010) 7. Combined .
  36. 36. Wide complex tachycardiaDiagnostic approach/algorithms WELLENS CRITERIA AKHTAR CRITERIA
  37. 37. Wide complex tachycardiaDiagnostic approach/algorithms BRUGADA CRITERIA Sensitivity – 98.7% Specificity – 96.5% Brugada P, Brugada Jet al.A new approach to the DD of a regular tachycardia with a wide QRS complex. Circulation. 1991;83:1649-16595
  38. 38. Wide complex tachycardiaDiagnostic approach/algorithms GRIFFITH CRITERIA WCT NO YES VT YES INDEPENDENT P WAVES Sensitivity – 95% Griffith MJ,Garratt Ci,et VT as default diagnosis in Specificity – 64% broad complex tachycardia. Lancet 1994 feb
  39. 39. Wide complex tachycardia Diagnostic approach/algorithms BAYESIAN CRITERIACRITERIA LR V WAVE IN LBBBQRS WIDTH r > 40MS 50 =140MS 0.31 NOTCH IN ‘S’ 50 140-160MS 0.48 R-S > 60MS 50 > 160MS 22.86 NONE 0.13QRS AXIS INTRINSICOID IN V6 NW AXIS 7.86 = 60MS 19.3 RBBB + LAD 8.21 < 60MS 0.46 LBBB + RAD 3.93 V6 MORPHOLOGY NONE 0.47 QS 50V WAVE IN RBBB BIPHASIC RBBB R/S<1 50 TALLER LT PEAK 50 TRIPHASIC RBBB R/S<1 0.13 Rs OR qR 4.03 rsR OR rR 0.21 NONE 1.41 Sensitivity – 95% Specificity – 52%
  40. 40. Wide complex tachycardiaDiagnostic approach/algorithms aVR CRITERIA Sensitivity – 96.7% Specificity – 99% Heart Rhythm, , Vereckei, A. et al. New algorithm using only lead aVR for DD of wide QRS complex tachycardia., 2008
  41. 41. Wide complex tachycardiaDiagnostic approach/algorithms Sen.10% The sensitivity [95.7 vs. Spe.100% 88.2, P < 0.001] and NPV [83.5% vs. 65.3% for VT Sen.48% diagnosis of the new Spe.98% algorithm were superior to those of the Brugada criteria Sen.89% Spe.89% Application of a new algorithm in the DD Sen.95% of wide QRS complex tachycardia Andra´s Spe.80% Vereckei et al . EHJ 2007.
  42. 42. Wide complex tachycardiaDiagnostic approach/algorithmsALGORITHM ORIGINAL STUDY LAU & NG(2001) ISENHOUR(2000) SEN. SPEF. SEN. SPE. SEN SPE.BRUGADA 98.7 96.5 92 44 79-91 43-70GRIFFITH 95 64 92 44BAYESIAN 95 52 97 56
  43. 43. Wide complex tachycardiaDiagnostic approach/algorithms Comparison of five electrocardiographic methods for differentiation of wide QRS-complex tachycardias Brugada, Bayesian, Griffith, and aVR algorithms, and the lead II R- wave-peak-time (RWPT) criterion All five algorithms/criteria had equal moderate diagnostic accuracy. The newer methods were not more accurate than the classic Brugada algorithm Comparison of five electrocardiographic methods for differentiation of wide QRS-complex tachycardias.Jastrzebski.M Europace 2010 feb 14
  44. 44. Wide complex tachycardiaBest algorithmic approach for diagnosing WCT1. BRUGADA2. aVR criteria3. Vereckei combined criteria(old & aVR criteria)
  45. 45. Wide complextachycardia

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