This document discusses the management of asymptomatic Wolff-Parkinson-White (WPW) syndrome. It outlines the risks of sudden cardiac death even in asymptomatic patients and challenges the approach of "leaving the patient alone." The document recommends using risk stratification to identify high-risk asymptomatic patients, such as those with a short accessory pathway effective refractory period (<250ms) or shortest pre-excited RR interval during induced atrial fibrillation (<250ms). For low-risk asymptomatic patients, close monitoring is recommended, while electrophysiological study with potential ablation is recommended for higher risk patients due to the risk of sudden cardiac death. Long-term studies show catheter ablation significantly reduces risks of malignant arrhythmias compared to

1. Asymptomatic WPW:
What to do?!
Salah Atta, MD
Professor of Crdiology
Cardiology department , Assiut University

2. Outlines
• The problem of asymptomatic WPW.
• leave him alone?!
• ablate and stop the debate?!
• Non invasive assessment of asymptomatic
WPW.
• Invasive assessment of asymptomatic WPW
• Updated recommendations and guidelines .

3. The problem
• A 25 yrs old male patient, with no history of
palpitations or syncope, or other cardiac
problems;
• Referred to you with this 12 lead ECG that was
done as a part of pre-employment
assessment….
• He is clinically and Echocardiographically free..
• You are asked for management and pre-
employment fitness opinion….

4. Patient’s ECG: what do you think?

5. The Wolf, Parkinson /White
syndrome
• In 1930, Wolff, Parkinson, and White
described a series of young patients
who experienced paroxysms of
tachycardia and had characteristic
abnormalities on
electrocardiography (ECG).

6. WPW pathophysiology
• Currently, Wolff-
Parkinson-White (WPW)
syndrome is defined as a
congenital condition
involving abnormal
conductive cardiac tissue
between the atria and
the ventricles other than
the A-V node His Purkinje
system…
The result is fusion of both normal and
accessory conduction
No
conductio
n
delay
AV
node Accessory
pathway

7. The Wolf Parkinson White (WPW)
Pattern
►►If the AP can conduct
antegradely rapidly,
Ventricular pre-excitation
will happen so the resting
ECG shows:
- Short PR interval < 120
msec
- Delta wave on the
upstroke of the QRS
complex with wide QRS >
120 msec.

8. Epidemiology of WPW syndrome
• Pre-excitation affects about 0.1% to 0.3% of the general
population.
• When pre-excitation
is accompanied by symptoms such as syncope or palpitations,
the diagnosis of Wolff-Parkinson-White (WPW)
syndrome is established (Munger et al , Circulation, 1993).
• Familial studies have shown a higher incidence of 5.5 in
1000 among first-degree relatives following an index
case of WPW.
• The most common presentation is orthodromic atrio-
ventricular re-entrant tachycardia or pre-excited atrial
fibrillation (AF).

9. Management of Symptomatic WPW

10. The problem of asymptomatic
WPW.
Identification of the truly asymptomatic patient with WPW
is difficult

11. The problem of asymptomatic
WPW.
• Young adult male
• No history of symptoms suggesting arrhythmia
or other cardiac problem (True asymptomatic)
• Clinically free
• ECG: WPW pattern
• Echocardiographically: no detected
abnormality….
What is your management and opinion ?!

12. Possible Management:
• 1- Do nothing… just leave him alone..!
• 2- Just ablate and forget about it…!
• 3- Attend this lecture to the end…!!!

13. Just leave him alone..!
Pros:
• Possible spontaneous cure:
In children and adolescents, the probability of
losing pre-excitation varies from 0 to 26 % while
13– 30 % of adults lose anterograde conduction
during 5-year follow-up.
• At present, it is estimated that approximately
65% of adolescents and 40% of individuals over
30 years with a WPW pattern on a resting ECG
are asymptomatic.

14. Why do not accept leaving him
alone?
Cons:
• As early as 1952, the 1st reported case
of WPW syndrome complicated by
cardiac arrest in VF was reported (Fox
et al).
• By 1971, the number of reported cases
reached 8 sporadic cases.

15. Incidence of sudden cardiac death in natural history
studies involving children and young adults

16. Risk of SCD in asymptomatic WPW
• Although most asymptomatic patients
with pre-excitation have a good prognosis,
there is also a lifetime risk of malignant
arrhythmias and SCD, estimated to be 0.1 %
per patient year. (Milstein et al 1986)
• More worrisome is the fact that this event can
be the first manifestation of the disease in up
to 53 % of patients.
(Della Bella et al, JACC 1996)

17. Mechanism of SCD in WPW
• Atrial fibrillation (AF) can be a life-threatening
arrhythmia in the WPW syndrome if the AV AP
has a short anterograde refractory period (RP),
allowing too many atrial impulses to be
conducted to the ventricle.
• This will result in very high ventricular rates
with possible deterioration into ventricular
fibrillation (VF) and sudden death. (Dreyfuset al
Circulation 1971, Klein et al N Engl J Med. 1979)

18. Sooooo
Just send him for ablation and finish
the problem?!

19. Just ablate and forget…!
Pros:
• Ablation eliminates all possible risks of
developing SVT or SCD in the future whether
low or high and stops the worry..
• High Success rate of RF ablation of APs in
general…
• Nowadays, You have a nearby active team of
EPS and radiofrequency ablation with regular
practice and good results.

20. Is it a risk free procedure?!
Cons:….
• The procedure is an invasive procedure,
• it has a low incidence of complications, but it may be
higher than the incidence of possible complications
of low risk WPW patients …..!
A- General complications of invasive cardiac Cath:
B- Risks Related to the location of the AP:
Ablation of a mid or anteroseptal AP (carries the risk of
complete AV block and possible need of a PPM).

21. What to do when meeting asymptomatic
WPW?
• You don’t have to decide immediately
• No medical ttt ….
• Identifying high risk asymptomatic patients
whose risk justifies the invasive interference..
• Risk stratification approach…is what we
need…

22. Risk stratification
Clinical Risk stratification:
1- Gender
2- Age
3- Professional and social factors…

23. Clinical Risk Stratification
Gender:
Timmermans et al. demonstrated that male gender
was associated with a significantly higher rate of
events than female gender (13 out of 15 events,
p=0.04).
Montoya et al. observed that male
gender was significantly more prevalent in patients
with VF.

24. Age as a risk factor
• Fan et al. showed that some electrophysiological (EP) properties of
the AP were associated with a higher risk of SCD were significantly
less prevalent in the older group (>50 years versus <30 years).
(Am Heart J, 1991)
• However, in a group of 92 asymptomatic patients (10–69 years),
Brembilla-Perrot et al. demonstrated that rapid conduction was seen
throughout the AP in all age groups (21 % in 10–69 year olds: 27 %
in 20–29 year olds, 27 % in 30–39 year olds, 6 % in 40–49 year
olds and 23 % in 50–69 year olds). They concluded that older
patients remain at risk of threatening arrhythmias. (Brembilla et
al 2001)

25. Age in Children
• It was thought that children below 12 years rarely gets AF…
• Pappone et al. in their study [New Ing JM, 2004] of five to 12-year
old WPW children, reported an apparently high incidence of induced
tachycardia (60/165) and spontaneous tachycardia in these children.
One case of sudden death and two cases of ventricular fibrillation
were reported in untreated children, the younger of whom was 10
years old.
• Sarrubi et al 2005, reported in their study a case of sudden death at
the age of 8 yrs.
• It is therefore widely recommended that a pre-excitation syndrome
be assessed from the age of seven years old onwards with no upper
age limit depending on the person’s activities.

26. Professional and Social factors:
- Type of Job : High risk Jobs as pilots, bus driver etc
- Level of stress or exercise exposure as competitive sports..
The most recent ACC/AHF/HRS guideline recommends catheter ablation as a
Class IIA recommendation in asymptomatic patients if the pre-excitation
precludes specific employment (such as pilots, Bus drivers, High competitive
sports).

27. Non Invasive Risk Stratification
We must use techniques which carry no risk
but which offer good diagnostic value.
The non-invasive methods however unfortunately offer
poor diagnostic value.
1- Surface Electrocardiogram (ECG)
2- The 24-h ECG Holter record
3- The exercise test
4- Medication Challenge

28. The resting surface
electrocardiogram (ECG)
• It may suggest a benign form of the
condition if the pre-excitation is
intermittent, although this is not a specific
finding [Kiger et al 2016].
• On the other hand, the presence of more
than one pre-excitation form suggestive of
multiple APs can be a sign of high risk…

29. Intermittent Pre-excitation

30. ECG Localization of AP
• Septal localization was significantly more frequent in
patients with VF when compared with individuals with
no VF. Timmermans et al.
Am J Cardiol 1995.
• More recently, Pappone et al. found that a
posteroseptal AP was present in 85 % of
asymptomatic patients who experience VF (11/13) as a
unique AP (7/11) or multiple APs (4/11).
• Assessment of risks associated with RF ablation.

32. Pamburn et al, JACC, 2018

33. Patient’s ECG: what do you think?

34. The accuracy, of AP location (90% vs. 63%; p < 0.001). The reproducibility was
excellent (p < 0.05) Pamburn et al, JACC, 2018

35. Rt Anteroseptal AP

36. The 24-h ECG Holter record
This can show:
• low risk sign like intermittent pre-excitation
• High risk signs like more than one form of
pre-excitation denoting multiple Aps or
• The method does provide an assurance that
no dysrhythmia as tachycardia, atrial
fibrillation not felt by a young child or adult is
recorded.

38. Exercise testing
• The exercise test is perhaps the most reliable way of
identifying a benign form of the disorder if the preexcitation
disappears suddenly [Levy et al 1979].
• We must be wary of progressive narrowing of the QRS
complex which may lead to the diagnosis of a false positive
benign WPW and miss a risk of sudden death. This situation
has already been published
• Daubert et al demonstrated that only abrupt and complete
loss of preexcitation during exercise confirmed a long
anterograde APERP. The positive predictive value was 40%
and the negative predictive value was 88%.
(Daubert et al. Am J Cardiol 1986.)

39. The exercise test

40. Medication challenge
• no longer routinely utilized,
• sodium channel- blocking agents pharmacologic
challenge with procainamide and propafenone.
• Accessory pathway block with medication challenge
was associated with a longer APERP at EP study.
• However, the specificity of loss of preexcitation after
administration of sodium-blocking medication was
poor compared to the shortest preexcited R-R
intervals during inducible AF.

41. Invasive Risk Stratification
• Patients in whom an abrupt loss of preexcitation cannot be
definitively documented, may be considered for an
electrophysiological evaluation (class IIa). (ACC/AHA/HRS
2016 guidelines )
• The decision to advise an invasive study and catheter
ablation of the accessory pathway was made individually,
depending on the age of the patient, the location of the AP,
and social and professional factors.

42. Role of Electrophysiological studies
• Electrophysiological studies were controversial, until 2003 as
until that time identifying malignant forms of the disorder
had not been found to be associated with a true risk of
event in patient follow up.
• It was Pappone et al. [JACC, 2003] who demonstrated in a
large series of 224 adolescents and young adults that 3
patients with rapid induced atrial fibrillation died because
they had declined ablation of their accessory pathway.

44. Electrophysiological Properties of AP
• The following characteristics have been related to the
risk of SCD:
• The Antegrade refractory period of the AP ( AERP):
the shortest cycle length with one-to-one conduction
by incremental atrial stimulation and,
• The shortest pre-excited R-R interval (SPERRI) during
spontaneous or induced AF.
• Multiple Aps
• Inducible AVRT of 1 minute or more…

45. How to do AP assessment during EPS ?!
• Incremental Atrial pacing will conduct through the
AP so long as the CL is longer than the AP antegrade
effective refractory period (AERP)

46. • Once block happens in the AP, pre-excitation will
disappear denoting reaching APAERP with narrowing
of QRS if ERP of AV node/His is shorter

47. Low risk AP

48. Short Antegrade refractory period
shorter than AVN/His

49. Value of AERP
• In 2009, Santinelli et al. presented the results of a longer prospective
observational study of 293 adults with asymptomatic pre-excitation in
whom a baseline EP study evaluating inducibility was performed.
• Arrhythmic events appeared within a median followup of 27 months
(range 8–55 months) in 10.5 % of patients (31/293) with a median age of
25 years: 5 % had AVRT (14/293) and 5.5 % had potentially life-threatening
arrhythmias (1.5 % AVRT degenerating into AF and 4 % with AF).
• In the multivariate Cox analysis, younger age, AERP ≤250 milliseconds and
inducibility were predictors of total and potentially life-threatening events.
There was a high predictive positive value of 80 % when all three factors
were present.

50. Assessment during induced
atrial fibrillation
• One of the best occasions to assess an AP,
when the patient gets transient AF during EPS
• If pre-excitation disappears during AF: It is a
safe AP with long refractory period.
• Pre-excited AF alone is not a high risk
sign…

51. Probably the most useful finding in risk stratification is
shortest pre-excited RR interval (SPERRI) during AF.

52. Value of SPERRI
• In an early series of patients resuscitated from VF related to WPW
syndrome, In a group of 25 patients presented with VF, the SPERRI was
significantly shorter than in the 73 individuals in the control group (240
± 63 milliseconds versus 180 ± 29 milliseconds) and did not exceed
250 milliseconds in any patient in the VF group. (Klein et al 1979)
• Sharma et al. (Am Coll Cardiol, 1987) found a mean SPERRI of 176 ± 33
milliseconds in WPW patients with VF and a SPERRI of ≤250 milliseconds
in 78 % of these patients (7/9) compared to 52 % of those without VF
(30/58).

53. Dangerous SPERRI
• Induction of atrial fibrillation conducted
rapidly by the accessory pathway (over
240/min at baseline base state i.e ,250 ms and
over 300/min i.e <200 ms on isoprenaline) can
identify a person with a malignant form of the
disorder.
[Wellens et al, Circulation 2005]

54. Induced pre-excited AF

55. High risk SPERRI during AF

56. Role of prophylactic Catheter
ablation
• In the largest and longest single-centre, prospective, observational study,
Pappone et al. observed asymptomatic and symptomatic WPW pts
subjected to EPS RF ablation in their center:
• Among 2169 enrolled patients, 1001 (550 asymptomatic) did not
undergo RFA (no-RFA group) and 1168 (206 asymptomatic) underwent
ablation (RFA group).
• Procedure outcome:
a success rate of 98.5 % in the ablation group (among the 1,168 patients,
206 were asymptomatic),
– no deaths were associated with the procedure and there was a very
low rate
of major complications (complete atrioventricular block in 0.08 %).
• All Pts whether had RF ablation or only diagnostic EPS were followed up
for 8 years….

57. • Kaplan–Meier analysis at 8
years showed that catheter
ablation was associated
with a significantly better
survival free from malignant
arrhythmias.
• 13 non-ablated asymptomatic
patients developed VF (aborted
cardiac arrest in all cases). All had
a SPERRI ≤240 milliseconds,
multiple APs were present in
31 % (4/13) and 69 % (9/13) were
inducible for AVRT triggering AF.
Role of prophylactic Catheter ablation

58. Role of prophylactic Catheter ablation

59. • Catheter ablation is reasonable in such patients if
high-risk features (AP effective refractory period
<240 ms, shortest preexcited RR interval <250 ms,
inducible AF or AVRT, presence of multiple APs, or
AVRT leading to preexcited AF) are identified.
• However, this decision has to be considered in the
context of the AP location and patient opinion.
Role of prophylactic Catheter ablation

60. 2015 ACC/AHA/HRS SVT Guidelines

61. Limitations
• Data supporting current recommendations are mostly derived from
observational studies, with few data coming from randomised clinical
trials, and most studies only include a small number of patients.
• The very low incidence of SCD in asymptomatic patients reported by most
studies has also contributed to the debate.
• As most patients are healthy young people who are expected to have a
long life, a large, long-term randomized clinical trial evaluating mortality
(no treatment versus catheter ablation) could provide the necessary
evidence-based information to support current recommendations.

62. Is WPW a haemodynamic disease?!
• Rarely patients present with WPW due to the
hemodynamic effects of preexcitation alone. This is
presumed to be due to dyssynchronous ventricular
contraction associated with a highly preexcited
rhythm.
(Emmel et al 2004)
• Tomaske et al 2008 found an improvement in
ejection fraction after ablation of septal accessory
pathways in pediatric patients. The prevalence of
septal pathways in the cases reported with
dysfunction may relate to the pattern of ventricular
activation in these specific pathways, but data are
limited.

66. Take Home Message

67. Brugada et al, 2018.

68. Thank You