This document discusses diagnosis and management of supraventricular tachycardia (SVT). It provides an overview of different types of SVT such as atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), atrial fibrillation (AF), and atrial flutter (AFL). It describes approaches to differentiate between these types based on electrocardiogram (ECG) patterns such as P wave morphology, PR and RP intervals. The document emphasizes using a physiological approach and considering the beginning and termination of the arrhythmia. It provides tips on localizing accessory pathways and discusses appropriate management strategies for different SVT types

1. Diagnosis and Management of
Supra-ventricular Tachycardia
Dr. D. Khanra
SR3
LPS Institute of Cardiovascular Sciences
GSVM Medical College, Kanpur
1

2. SVT in a nut-shell
Onset
Termination
2
AVNRT AVRT AT
AFLAVNRT

3. Regular Narrow QRS Tachycardia
Visible P Waves AF / AT /AFL
A >V
AFL /AT ? RP Interval
Short Long
< 70 ms > 70 ms
AVNRT
AVRT / AVNRT /
AT
AT / PJRT /
Atypical AVNRT
Yes No
Yes No
Yes
No
Pattern recognition vs Physiological approach
Wide freeways but narrow viewpoints
3

4. Breaking complexity with complexity
Differentials
• AT
• AFL
• Afib
• AVNRT
• AVRT
• JT
• VT
‘’Game Plan’’
• What’s the ‘drill’? eg. NCT vs WCT
• Eyeballing morphology? eg. VT criteria
• ‘Smoking gun’? eg. PR prolongation
• Pre test prob? eg. Patient profile, age, MI
• Absolute vs probable? eg. Termination with P
• Having a ‘tool box’! eg. P, delta, PR/ RP, axis, BBB
• ‘Big picture’ working diagnoses Be Open-minded
Beginning + tachycardia + termination = SVT
4

5. Hunt for P
Look at the Ts
Seek for the
midpoint
High to low P
(anterograde)
Low to high P
(retrograde)
5

6. ST: high to low: warm up usually present
No P at al: AVNRT> JT
Low to high P: AT/ AFL (non sinus), PR short
if retrograde: very long RP: atypical AVNRT
Pseudo q pattern in 4% of AVNRT
Pseudo S: AVNRT
Rarely, JT with VA conduction
RP short: AVNRT
AVRT may be possible
RP longer: AVRT (<50% of RR)
Atypical AVNRT if RP >50% of RR
Variable P + PR+ RR = MAT
AV dissociation
JT > VT
Myriads of P
6

7. Think physiologically
VV dictates AA
Ventricular participation +ve
AT ruled out, can be VT/ AVRT
AA dictates VV
Atrial participation +ve
VT ruled out, can be AT/ AVNRT
No PR prolongation
So no AVN involvement
Can not be AVNRT/ o-AVRT
PR prolongation
So AVN involvement
AVNRT/ o-AVRT 7

8. Do not miss ‘The End’
Ends with P
Can not be AT
Can be AVNRT/ AVRT/ VT/JT
Ends with no P
Can be anything
VAV (not AT)
vs VAAV (AT)
AT
8

9. AVRT caught red-handed!
RR alternans
ITS NOT AF
BBB normalises: Ipsilateral AP
9

10. LBBB + Right axis (discordant): VT likely
North west axis: VT likely
Axis helps
Axis changes
With onset of tachy
Or after termination
VT is likely
10

11. No RS in precordial lead: VT
Absolute vs probable
Sudden transition is V3: AP/ VT 11

12. AV dissociation: VT (may be in JT also)
Capture/ fusion: VT (may be in a-AVRT also)
‘The smoking gun’
12

13. Localising AP
-ve Delta
1. In I: left lat AP (most common)
2. In II: CS AP (adenosine sensitive)
3. In V1: Septal AP (DD AVNRT)
4. Rest: right lat AP
13
QRS transition AP localisation
At or before V1 Left sided pathways
b/w V1 – V2 or at V2 Mostly Right sided pathway
Lead 1: R>S Right sided pathway
Lead 1: R<S left sided pathway
b/w v2-v3 Right septal pathway
After v4 Right lateral pathway
Onset of LBBB prolong TCL: left sided AP
Onset of RBBB prolong TCL: Right sided AP
ECG mimicking IWMI: CS or post-septal AP
Fitzpatrick’s algorithm

14. AP: benign or malignant?
14Late coupled PAC renders AP to refractory Even prolonged PR did not start AVRT
Different level of fusion depending on prematurityBenign

15. His-refractory VPC
Long RP
BUT >50% of RR
BUT NOT atypical AVNRT
A advanced by his refractory VPC
SA – VA < 85 ms suggests AP
PPI – TCL <115 ms suggests AP
TCL PPI
NO Reset
AVNRT 15
Capture & Reset
= AVRT

16. Identifying Focus of AT
16
Focus of AT P in Limb leads P in Precordial leads
High Crista Terminalis (MC) Inf leads –ve
AVR +ve
-ve to +ve
Coronary sinus (Adenosine) Inf leads +ve
AVR -ve
+ve to -ve
Pulm veins (RSPV MC) I, AVL -ve All +ve
(large to small)
LA (LAA Mostly) least of all I, AVL -ve
Or flat
All –ve
Or flat
Zhi Young’s algorithm
Clin EP 2011

17. Short PR is not synonymous to AP
 Anterograde AP PR (<50ms)
 AT near to AVN PR (>50 ms) (low to high P)
 AFL near to CS (low to high P) (baseline undulating)
 JT with non conducted P (high to low P) (structural heart dis)
17

18. RP and PR
PR RP Diagnosis
const const ST
varies varies AVNRT
Varies const AVRT
const varies AT
RP is religiously fixed: AVRT
PR is religiously fixed: AT
Typical AVNRT: PR>RP
Atypical AVNRT: RP>PR
AVNRT:
Pseudo R in v1
Pseudo S in inf leads
Also pseudo q in 4% 18
AVRT:
Long RP
Distorts ST/ T
Mostly Left lat AP

19. Ugly BBB
LBBB
Rapid & steady descent
SVT
Slow & stuttered descent
VT
RBBB
later peak taller
SVT
First peak taller
VT
Bizarre BBB also in a-AVRT, ischemia
19

20. Looks are deceptive!
Morphology Criteria
Not very reliable
However,
the best
20

21. Grey Matter wins over ICD algorithms
21

22. 22
Mechanism of arrhythmia?
Warm up and cool down
Rate <200
TCL variation >30ms
P anterograde
VAAV
Abrupt onset & offset
Rate >200
TCL variation <30ms
P retrograde
VAV
Rare
Precipitating factors
Eg QT long
Slow
velocity
Cut
Propagation
No overdrive
Suppression
Overdrive
Modify
Physical
milieu

23. How to manage?
23
Scenario Management
AVN involved in tachycardia
O-AVRT AVNRT JT
AVN blocker
(Adenosine, Diltiazem)
Long term: Diltiazem/ Verapamil in AVNRT
Sotalor for AVRT (blocks AVN and AP)
AVN not involved in tachycardia
A-AVRT with AF AFL
AVN blockers contraindicated
Amiodarone increases ERP of AP
May be terminated with Adenosine if near CS
Long term: Amiodarone
AT AFL Diltiazem blocks AVN
Reduces FVR
May be terminated with adenosine If near CS
Long term: beta blockers/ CCB
If hemo-dynamically unstable DC shock
(Heparin)
If recurrent AVNRT: RFA of slow pathway
AVNRT: RFA of AP

24. What we have learned?
24
 Be careful with the Ps
 Do not miss the beginning and the end
 Old ECG records are valuable for any axis change or BBB
 Ectopic activity during tachycardia is a gift
 Short PR doe not always mean WPW
 Long RP does not always mean AVRT
 Bizarre BBB does not always mean VT
 AV dissociation/ capture does not always mean VT
 Looks can be deceptive. Spinal reflexes are not wise
 So, think physiologically. And be logical & open-minded

25. Who have
NOT ARGUED
over a diagnosis of tachycardia
their colleagues?
25

26. QUIZ ECG # 1
26
If o-AVRT (LL AP), why no early transition in V1-V2?
How come varying degree of capture at same rate?
ANS: recurrent VPCs (‘’R on P’’)

27. 27
QUIZ ECG # 2
APC (within T) prolongs PR and starts o-AVRT
With the resolution of LBBB TCL shortens
ANS: o-AVRT (Left lateral pathway)

28. 28
QUIZ ECG # 3A
Regular WCT with LBBB morphology
Low to high P (retrograde), RP short
Axis normal, transition at V5
In V1, descent of QRS is little staggered
What would you do next?

29. 29
QUIZ ECG # 3B
Post Diltiazem
ANS: AFL 1:1 converted to 2:1

30. 30
QUIZ ECG # 4
A C C
F F F
A A A
NCT retrograde P long RP normal axis
Atypical LBBB, sudden transition in V3
Capture/ Fusion/ AV dissociation (so NOT AVRT)
ANS: VT

31. 31
QUIZ ECG # 5
Long RP, RP less than 50% of RR, BUT PP dictates RR (so no AVRT)
Terminates with P (not AT), RP<PR and RP,PR both variable
ANS: AVNRT (? Atypical)