ΗΚΓ Διαφορική Διάγνωση Υπερκοιλιακών Ταχυκαρδιών

Transcription

1 ΗΚΓ Διαφορική Διάγνωση Υπερκοιλιακών Ταχυκαρδιών Ελευθέριος Μ. Καλλέργης Καρδιολογική Κλινική Πανεπιστημιακό Νοσοκομείο Ηρακλείου

2 The First Classification of Arrhythmias Differentiated paroxysmal atrial tachycardia from paroxysmal ventricular tachycardia Thomas Lewis Paroxysmal tachycardia. Heart (br cardiac soc) 1909;1:43-72

3 Classification of SVTs based on Mechanism

4 SVT - Systematic Approach Relative position of the P wave & R-R interval Mode of initiation Mode of termination Morphology of the P wave Variation of cycle length Effect of AVB and BBB on the tachycardia Response to Valsalver Maneuver/ AVN blocker

5 PR and RP Timing

6 PR-RP Relationship Typical AVNRT

7 Short RP Tachycardia Typical AVNRT (slow-fast)

8 Long RP Tachycardia Atypical AVNRT (Fast-Slow) AVNRT

9 PR-RP Relationship - AVRT

10 Short RP Tachyardia Orthodromic AVRT

11 Long RP Tachycardia PJRT Permanent junctional reciprocating tachycardia

12 PR-RP Relationship - AT

13 Looking at the PR-RP Intervals Long RP tachycardia Sinus tachycardia Atrial tachycardia Some AVRTs Junctional tachycardia Atypical AVNRT RP PR RP PR Short RP tachycardia Typical AVNRT Most AVRTs A tach with long PR interval RP<PR (Short RP) RP>PR (Long RP)

14 SVT - Systematic Approach Relative position of the P wave & R-R interval Mode of initiation Mode of termination Morphology of the P wave Variation of cycle length Effect of AVB and BBB on the tachycardia Response to Valsalver Maneuver/ AVN blocker

15 Mode of Initiation Gradual Onset/ Warming up Sinus tachycardia PR Jump in typical slow-fast AVNRT Junctional ectopic tachycardia (JET) QRS complex If a PVC initiates SVT, it is likely to be morphology AV node dependent Sudden Onset AT AVNRT AVRT SART Assess any change of: PR interval Orthodromic AVRT Loss of pre-excitation Variation of atrial cycle length & P wave morphology Atrial Tachycardia

16 Mode of Initiation Initiation of a supraventricular tachycardia by a single VPB argues in favour of a circus movement tachycardia, incorporating an accessory atrioventricular pathway

17 Initiation of AVNRT PR Jump upon initiation of typical slow-fast AVNRT Short RP Retrograde via Fast Pathway (VA or RP < 70ms) Long PR Antegrade via Slow Pathway

18 Initiation of Orthodromic AVRT Conduction down AV axis during tachycardia gives NARROW QRS complex

19 Mode of Initiation - AT

20 SVT - Systematic Approach Relative position of the P wave & R-R interval Mode of initiation Mode of termination Morphology of the P wave Variation of cycle length Effect of AVB and BBB on the tachycardia Response to Valsalver Maneuver/ AVN blocker

21 Mode of Termination Spontaneous Termination with a P wave Unlikely AT (In which case the last atrial beat before termination have to coincide with AVB) Spontaneous Termination with a QRS complex Not helpful in differentiation

22 Mode of Termination

23 Mode of Termination It is extremely unlikely that an AV nodal tachycardia will be terminated by a single VPB, whereas this is common in acircus movement tachycardia using an accessory AV pathway for ventriculo-atrial conduction

24 SVT - Systematic Approach Relative position of the P wave & R-R interval Mode of initiation Mode of termination Morphology of the P wave Variation of cycle length Effect of AVB and BBB on the tachycardia Response to Valsalver Maneuver/ AVN blocker

25 Morphologies of P waves pseudo-r

26 Morphologies of P waves pseudo-s

27 Morphologies of P waves ST elevation in lead avr is strongly suggestive of WPW-related narrow complex tachycardia Ho YL, et al. Am J Cardiol. 2003; 92(12):1424-8

28 Morphologies of P waves

29 Morphologies of P waves A negative or biphasic (+, -) P-wave in lead V1 was associated with a 100% specificity and PPV for RA tachy. A positive or biphasic (-, +) P-wave in lead V1 was associated with a 100% sensitivity and NPV for LA tachy.

30 Morphologies of P waves MAT Multifocal Atrial Tachcyardia

31 Differentiating typical AVNRT from AVRT Sensitivity Specificity Positive Predictive Value AVRT Visible P wave 95% 58% 71% P wave onset 100/ms 84% 91% 91% P wave onset 80/ms 95% 70% 78% ST-depression 2 mm 47% 79% 71% AVRNT Pseudo r wave on lead V 1 55% 100% 100% Pseudo S waves on inferior leads 20% 100% 100% Jaeggi E et al. Am J Cardiol 2003;91:

32 Differentiating typical AVNRT from AVRT Jaeggi E et al. Am J Cardiol 2003;91:

33 SVT - Systematic Approach Relative position of the P wave & R-R interval Mode of initiation Mode of termination Morphology of the P wave Variation of cycle length Effect of AVB and BBB on the tachycardia Response to Valsalver Maneuver/ AVN blocker

34 Variation of Cycle Length Variation of cycle length and QRS alternans can occur in AVRT with multiple accessory pathway Atrial tachycardia AVNRT with > multiple slow/fast pathways AVRT with coexisting dual AVN physiology Change in P-P interval preceding change in R-R interval Less useful for diagnosis (usually AT, but can be AVNRT or AVRT) Change in R-R interval preceding change in P-P interval Unlikely AT

35 Variation of Cycle Length

36 QRS Alternans QRS alternans - Phasic alternation of QRS amplitude Most commonly in AVRT 25-38% of orthodromic AVRT 13-23% of AVNRT, but virtually never seen in AT

37 SVT - Systematic Approach Relative position of the P wave & R-R interval Mode of initiation Mode of termination Morphology of the P wave Variation of cycle length Response to Valsalver Maneuver/ AVN blocker Effect of AVB and BBB on the tachycardia

38 Determining AV Nodal Participation in SVT Vagotonic Maneuvers Carotid massage sinus Valsalva maneuver (bearing down) Facial ice pack ( diving reflex; for kids) Adenosine

39 SVT Responses to AV Nodal Depressant Maneuvers If SVT breaks, a reentrant mechanism involving the AV node is likely If the tachycardia is associated with AV dissociation the diagnosis of AVRT is excluded If atrial rate unchanged, but ventricular rate slows SVT is atrial in origin AVNRT with lower common pathway block No SVT termination (despite maximal attempts) Sinus tachycardia Atrial flutter or fibrillation Most atrial tachycardias (a minority are adenosinesensitive )

40 SVT Responses to AV Nodal Depressant Maneuvers Ganz LI, Friedman PL. N Engl J Med 1995;332:

41 Effect of Intermittent BBB during SVT Prolongation of tachycardia cycle length and R to P time with BBB the bundle branch is part of the tachycardia circuit AVRT with Accessory Pathway on the same side of the bundle branch block BBB with no effect on tachycardia cycle length / R to P time the bundle branch is not integral part of the tachycardia circuit AVRT with accessory pathway contralateral to the bundle branch block AT AVNRT

42 Effect of Intermittent BBB during AVRT

43 Effect of Intermittent BBB during AVRT Conduction block in the contralateral bundle (RBBB) does not affect The tachycardia cycle length and VA conduction time, as it is not involved In the tachycardia circuit

44 PJRT

45 Conclusions Major advances have been made in our abiiity to correctly interpret the 12-lead electrocardiogram of SVTs This has made the ECG a reliable and inexpensive tool with wich to diagnose the site of origin and frequently the mechanism of a SVT Providing the first Step in guiding our therapeutic approach