Athletes with channelopathy may be eligible to play
Neth Heart J
Athletes with channelopathy may be eligible to play
N. M. Panhuyzen-Goedkoop 0 1 2
A. A. M. Wilde 0 1 2
0 Radboudumc Nijmegen , Nijmegen , The Netherlands
1 Sports Medical Centre Papendal , Arnhem , The Netherlands
2 Heart Centre, Department of Clinical and Experimental Cardiology, Academic Medical Centre , Amsterdam, Amsterdam , The Netherlands
The European and Bethesda recommendations roughly state that any athlete with channelopathy is not eligible to participate in sports on a presumed risk of potentially life-threatening ventricular tachycardia or fibrillation. However, eligibility decision-making on a presumed risk of ventricular tachycardia or fibrillation is debatable. Channelopathies are primary electrical cardiac disorders and are usually transmitted as an autosomal dominant trait. Some of the channelopathies are potentially fatal in relation to exercise and predispose to life-threatening cardiac arrhythmias including ventricular tachycardia or fibrillation. Exercise, swimming, body heating and electrolyte depletion can all act as a trigger of ventricular tachycardia or fibrillation in channelopathy. However, new research mentioned a very low incidence of ventricular tachycardia or fibrillation in athletes with channelopathy challenging the decision of disqualification. Recently, the American recommendations for sports participation in athletes with a cardiovascular disorder have updated their eligibility decision-making. In this manuscript we describe the signature features of the electrocardiogram changes in channelopathies and we argue that new research data should allow for the introduction of more liberal eligibility decision-making for sports participation in athletes with channelopathy, not only in the United States but also in European countries.
Channelopathies are inherited primary electrical disorders
without structural abnormalities. Channelopathies are rare
and usually transmitted as an autosomal dominant trait.
The four major channelopathies are long QT syndrome
(LQTS), short QT syndrome (SQTS), catecholaminergic
polymorphic ventricular tachycardia (CPVT) and Brugada
syndrome (BrS) [
]. Channelopathies are identified by
a 12-lead electrocardiogram (ECG) or genotyping [
Some of the channelopathies are potentially fatal in
relation to exercise and predispose to life-threatening cardiac
arrhythmias including ventricular tachycardia or
fibrillation (VT/VF). The prevalence of sudden cardiac death
(SCD) events in American young competitive athletes
due to channelopathy is 4%, including 3.6% LQTS and
In this manuscript we describe the signature features of
the ECG changes in channelopathies and we argue that
new research data should allow for the introduction of more
liberal eligibility decision-making for sports participation in
athletes with channelopathy, not only in the United States
but also in European countries.
An athlete is an individual exercising regularly in
competition or leisure-time aiming at improving him/herself.
A young athlete is he/she aged 35 years and younger.
Regular sports participation with a certain intensity
induces cardiac adaptation. Dynamic sports induce dilatation
of the cavities and static sports induce thickening of the
myocardium. Every sports type is classified in low,
intermediate and high dynamic and/or static sports [
triathlon and cycling for instance are high dynamic high
static sports, and golf, billiards and riflery are low dynamic
low static sports [
Electrocardiography in eligibility screening
A 12-lead resting ECG in eligibility screening in athletes
is generally the clue to the presence of channelopathy [
]. In LQTS the QTc interval is prolonged, and the
signature arrhythmia of LQTS is the ‘Torsades de Pointes’
arrhythmia. This is a high-rate polymorphic ventricular
arrhythmia characterised by a shifting electrical axis leading
to syncope and sudden cardiac arrest/sudden cardiac death
]. The cut-off point of QTc interval
prolongation in LQTS is generally accepted to be ≥500 ms—using
Bazett’s formula—in repeated ECGs without known cause
]. However, for unclear reasons, in athletes a lower
cut-off point ≥470 ms in males and ≥480 ms in females
is used [
9, 10, 17, 24–27
]. Basavaradjaiah et al. found
a low prevalence of LQTS in elite athletes (n = 7/2000)
with QTc interval ≥470 ms. They also found that signs
of LQTS—absence of QT interval adaptation during
exercise, presence of a gene mutation, QTc prolongation in
first-degree relatives—were associated with a QTc interval
≥500 ms [
]. The authors concluded that a QTc cut-off
point ≥500 ms can be used in athletes provided there are no
signs and symptoms—dizziness, syncope—of LQTS [
Maybe in future recommendations the QTc cut-off point
in athletes can be considered similar to the cut-off point
in the overall population. The responsible ion current for
the QT interval adaptation process—paradoxical
prolongation—during exercise is the catecholamine-sensitive slow
component of the delayed rectifier—i. e. IKs. In LQTS-1,
this current is not functioning optimally and hitherto
aberrant QTc prolongation occurs during an increase in heart
rate. In LQTS-2 and LQTS-3, IKs functions properly and
the QTc interval shortens appropriately during an increase
in heart rate. This is particularly noted in LQTS-3 where QT
intervals are prolonged predominantly during bradycardia
and are completely normal at faster rates. The QT intervals
in LQTS-2 lag behind compared with normal physiological
In SQTS the QTc interval is too short and does not
change during exercise [
]. The signature arrhythmia
of SQTS is atrial fibrillation or VT/VF. The disease is
highly fatal [
]. In SQTS there is no defined
cutoff point of a short QTc interval associated with
potential VT/VF in athletes. The guidelines of the European
Society of Cardiology (ESC) describe that SQTS is
diagnosed in the presence of a QTc interval 330 ms .
Several studies observed a very low incidence of SCA/SCD
(0.02–0.1%) in the overall population and in athletes with
a SQTS using different QTc cut-off points of 320 ms or
300 ms [
]. In addition, the short QTc interval was
associated with an increased risk of recurrent SCD if the
QTc interval was short [
]. Furthermore, these studies—
using different cut-off points—demonstrated that male and
African/Afro-Caribbean athletes were more likely to have
a shorter QTc interval than female and Caucasian
]. Based on these studies we can conclude
that African/Afro-Caribbean and Caucasian athletes with
a QTc interval 320 ms are highly suspicious of SQTS
and require additional cardiac evaluation, and symptomatic
SQTS athletes should be restricted from sports participation
]. Furthermore, quinidine or sotalol, both
prolonging the short QTc interval, can be used and implantable
cardioverter defibrillator (ICD) implantation should be
considered to prevent SCA/SCD [
CPVT is the only major channelopathy with normal
ECG findings at rest. The signature feature is an
exercise/emotion-induced ventricular arrhythmia, often already
seen in paediatric age groups (age 5–6 years) [
arrhythmia typically starts with monomorphic ventricular
ectopy at a certain heart rate that is quite consistent for
a given patient [
]. The typical heart rate at which
ventricular ectopy develops is patient-dependent and usually
in the range of 90–120 bpm. In addition, any
extrasystole in morphologically normal hearts not originating from
the right ventricular outflow tract should raise suspicion
in relevant circumstances. It becomes more
characteristic with polymorphic doublets—one is enough—and
pathognomonically with bidirectional VT—which can be
short—inducing episodes of syncope [
into VF can occur. It is generally stated that in every athlete
with CPVT physical exercise should be prohibited without
In BrS, recognising the typical Brugada pattern on the
12-lead resting ECG can be a challenge. However, BrS is
a clear-cut electrophysiological diagnosis [
diagnostic type 1 ECG is defined as a spontaneous high
takeoff and downsloping ST-segment elevation of more than
2 mm above the baseline J-point in the right precordial
leads (V1–3) followed by a negative T-wave [
1, 2, 37,
]. If there is suspicion of BrS high lead placement of
V1-3 in the second and third intercostal spaces may
unmask a Brugada pattern. However, in a pilot study in Dutch
athletes (<24 years, n = 350) we did not find a Brugada
pattern with high lead placement (Panhuyzen, unpublished
data). If there is suspicion of the Brugada pattern
provocation studies with a sodium channel blocker—i. e.
preferentially ajmaline or flecainide—may be considered. However,
the specificity and sensitivity of the drug challenge test is
increasingly questioned [
]. In addition, the risk of
SCA/SCD is very low (<0.05%/year) if the provocation
study with a sodium channel blocker in BrS induces
ventricular arrhythmia only [
]. Besides, the mechanism
of inducing a fatal arrhythmia in BrS with a drug challenge
test is different from exercise-induced VT/VF. Furthermore,
the Brugada pattern should be distinguished from Brugada
phenocopies and early repolarisation [
27, 37, 38, 41
latter is a normal finding in highly trained endurance
27, 38, 41
]. Brugada phenocopies are a group of
heterogenous conditions with Brugada-like ECG findings, lack
of symptoms suggestive of BrS, negative family history of
BrS or SCA/SCD, negative drug challenge test, and
negative genetic testing [
]. In addition, SCA/SCD in BrS is
generally unrelated to exercise, but occurs most often
during sleep. There seems to be no evidence whatsoever to
exclude these individuals from sports participation [
14–16, 40, 44, 47
The athlete is referred for additional cardiac evaluation if
the ECG findings in eligibility screening raise suspicion of
channelopathy and the athlete is temporarily restricted from
sports participation [
]. Cardiac evaluation includes—if
indicated—exercise testing, Holter monitoring,
echocardiography, MRI and/or, possibly, genetic counselling [
]. An electrophysiologic (EP) study is not
recommended in the evaluation of the risk of VT/VF in
channelopathy (class III indication, level of evidence C), except
for BrS (Class IIB indication, level of evidence C) [
Sports-specific stress testing until exertion and Holter
monitoring during training sessions have the potential to
capture relevant ventricular arrhythmias [
]. In LQTS-1,
for instance, the key feature is a paradoxical prolongation
of the QTc interval at higher heart rates. In SQTS the QTc
interval remains short, and in CPVT the key feature is an
increasing number of ventricular arrhythmias with
on-going exercise as described above. In addition, frequent and
complex ventricular ectopy (burden >1% or >2000/24hrs)
in trained athletes seems to be related to structural cardiac
Genetic counselling and family screening
Genetic testing in the proband and/or his/her first-degree
family members is considered in the diagnostic evaluation
in athletes with abnormal screening findings suspicious of
]. However, when an athlete suddenly
dies, and autopsy confirms the absence of structural heart
disease, genetic testing of the deceased should be
considered to identify the channelopathy gene and confirm the
]. Once the gene is identified family
screening can be considered. Unfortunately autopsy studies are
not performed routinely in all countries and the question
regarding the cause of death remains often unsolved. We
should note that a negative genetic test result does not
exclude the presence of an inherited disease.
More liberal eligibility decision-making
Current and new developments in the diagnosis and
management of channelopathies probably control the risk of
exercise-related cardiac events—i. e. VT/VF—better than
before, suggesting that eligibility decision-making in
channelopathy may be more liberal [
9, 10, 13, 21
]. In VF slow
calcium channels as well as sodium channels are involved in
the initiation of VF . It is generally accepted that certain
lifestyle features may increase the risk of VT/VF in athletes
with channelopathy [
1, 2, 17, 27, 36, 43
drugs (www.crediblemeds.org) in LQTS and drugs
aggravating the disease (www.brugadadrugs.org) in BrS should
be avoided. In addition, it is recommended to avoid
hyperthermia and/or excessive sweating in channelopathy. The
physiologic process of a higher core temperature during
exercise is associated with vasodilatation and sweating to
prevent the body from heating—body temperature >40
degrees Celsius. However, in exceptional cases and in exercise
during fever the body temperature can increase to a
dangerous level and fatal arrhythmias may occur. It is generally
accepted that athletes with BrS and/or certain LQTS
mutations should avoid exercise in hot conditions and during
fever to prevent body heating [
1, 2, 17, 27, 36, 43
Prophylactic use of acetyl-p-aminophenol 500 mg seems
controversial. Burtscher et al. measured the body temperature
in a randomised cross-over trial in seven male young
nonfeverish athletes who used prophylactic
acetyl-p-aminophenol 500 mg or a placebo two hours before exercising on
a treadmill in a climate chamber at 30 degrees Celsius
at an individual intensity of 70% VO2max [
increase in body temperature was slightly reduced by
acetylp-aminophenol from 38.4 to 38.0 degrees Celsius and the
physical performance remained unaffected [
there are no data on prophylactic acetyl-p-aminophenol in
channelopathy to avoid body heating.
The recommendations of the American Hearts
Association (AHA) and the American College of Cardiology (ACC)
for athletes published in 2015 are the first to be more
liberal in eligibility decision-making in athletes with
inherited CVD [
]. Overall, we do agree with these
recommendations, although the level of evidence is low.
However, the international guidelines on the primary
arrhythmia syndromes need to be considered when we want to
describe more specific recommendations for athletes with
channelopathy, taking into account the stage and type of
the channelopathy, and the intensity and type of the sport
practiced by the athlete [
In a large Italian screening study, young athletes with
LQTS—0.6% of all non-eligible athletes—were
disqualified on a presumed risk of an exercise pro-arrhythmic
trigger of VT/VF [
]. During follow-up no cardiac events in
the disqualified athletes were reported [
]. After more than
30 years of screening (n = 42,386) the authors observed that
only two of the LQTS cases had died suddenly [
Johnson et al. have studied athletic participation and
LQTS-related events in a retrospective case record study in
gene-positive young LQTS athletes—aged 6–40 years—who
continued sports participation despite medical advice (n = 157)
after being informed in detail about the risk of sports
participation by reading the Bethesda conference
guidelines, which was also agreed upon by the parents in case
of a minor [
]. The vast majority of athletes were treated
with β-blocking agents (95%) and, if deemed necessary,
implantation of ICD (n = 20). They were advised to avoid
dehydration, body heating, electrolyte disturbances and
QT-prolonging drugs and were instructed to carry their
own automated external defibrillator (AED) in their
equipment. During a mean follow-up of 5.5 years in 60 athletes
participating in all sports no cardiac events were reported
except for one boy. The boy had unexplained fainting
during physical and emotional stress with a QTc interval
490 ms at age 7 years. When his QTc interval prolonged to
>550 ms he suffered from SCA and an ICD was implanted.
He had two appropriate VF-terminating ICD shocks during
soccer and basketball while being non-compliant with his
β-blocking agents [
]. To date this is the only study in
a large number of gene-positive LQTS patients
demonstrating the relative benign nature of appropriately treated
LQTS and it tends to show that disqualification on a
presumed risk of VT/VF is not justified. However, it remains
uncertain if an ICD provides safe protection for SCD in
athletes with channelopathy [
]. Colman et al. have
compared case records of LQTS patients presenting with
syncope (n = 41) in an unselected group of syncope patients
(n = 113) presenting at the emergency department . The
authors concluded that a positive family history for sudden
cardiac death (n = 21), palpitations prior to syncope (n = 12),
syncopal episodes in supine position (n = 24), and syncopal
episodes related to exercise (n = 10) and emotional stress
(n = 21) are more common among patients with LQTS [
To date in SQTS there are no studies in athletes to
determine the risk of VT/VF in relation to exercise.
Ostby et al. (Mayo Clinics) observed in a follow-up
study of adolescent CPVT athletes (n = 21/63) who
continued competition after shared decision-making that only
three athletes suffered a cardiac event during exercise [
Prior to the diagnosis, 16 of the 21 athletes continuing
competition had experienced CPVT-triggered events. They
concluded that the risk of cardiac events in well-treated and
well-informed athletes with CPVT may be acceptable,
although CPVT if untreated poses a high risk of VT/VF [
Athletes are usually more aware of their physical
well-being and the risk associated with their sports than the
overall population. However, when an athlete is identified with
channelopathy it is very important to discuss all the
information the athlete needs for shared-decision making in the
management of and recommendation for sports
participation. This is probably the most important part in the sports
In a review study of 18 articles, Masrur et al. indicated
that there were only limited data in BrS patients describing
exercise-related VT/VF and stated that the risk of fatal
arrhythmias seems to be unclear [
]. Olde Nordkamp et al.
have reviewed case records of BrS patients (n = 342) with
aborted SCA (n = 23) or non-arrhythmic syncope (n = 118)
]. The SCA was not triggered by high temperature, pain
or emotional stress. Those with syncope experienced their
first event at an older age (mean age 45 years) than the
SCA group (mean age 20 years). The authors concluded
that arrhythmic and non-arrhythmic syncopes often occur
in BrS [
In an international ICD registry in athletes, Lampert et al.
found that except for VF terminating ICD shocks (n = 37)
no cardiac events were reported in athletes with an ICD
who continued sports participation in organised (n = 328)
or high-risk (n = 44) sports against medical advice [
this study cohort 73 athletes had LQTS, 10 CPVT and 7 BrS
]. VF terminating shocks occurred in two athletes with
LQTS and in one with CPVT. Although the authors
concluded that athletes with an ICD can participate in
competitive sports without failure of VT/VF termination or physical
injury, it is uncertain whether an ICD provides sufficient
protection to prevent SCD related to sports participation
No event in the past
Consider competitive sports
Avoid drugs that may
aggravate the disease
hyperthermia, and exercise
while suffering from a fever
Avoid QT-prolonging drugs
excessive sweating, electrolyte
and exercise while suffering
from a fever
LQTS1: no swimming,
diving, immersion in cold
Avoid dehydration and/or
exercise while suffering
from a fever
CPVT catecholaminergic polymorphic ventricular tachycardia, ICD implantable cardioverter defibrillators, SCA sudden cardiac arrest,
SCD sudden cardiac death, + positive, – negative
Considering the few, but important, studies mentioned
above, we would like to propose more liberal eligibility
decision-making in athletes with channelopathy (Tab. 1):
Eligibility decision-making in LQTS
1. In asymptomatic phenotype-positive LQTS with QT
interval ≥500 ms sports participation is restricted, and
β-blockers are recommended.
2. In symptomatic phenotype-positive LQTS (syncope,
dizziness) sports participation should be restricted and
only low intensity sports (Mitchell’s classification of
sports), can be considered. β-blockers are recommended.
ICD implantation is recommended in patients with
previous SCA and in patients with syncope and/or VT while
receiving β-blockers [
3. When there are no ventricular arrhythmia events recorded
with the ICD during at least 3-month follow-up and the
QTc is <500 ms recorded on repeated ECGs the physician
may consider return-to-play in sports provided the athlete
does not participate in swimming and diving (LQTS-1).
4. Genotype-positive phenotype-negative LQTS
individuals—i. e. ECG diagnosis of LQTS without symptoms
related to LQTS—are allowed to participate in all sports.
In general, a family history of fatal cardiac events has
not been associated with a higher risk for cardiac events
in subsequent family members and in all survival
analyses phenotype-negative patients (i. e. normal QTc) have
a much lower risk compared with their
phenotype-positive family members [
5. All patients with LQTS QT prolonging drugs (www.
crediblemeds.org) should avoid dehydration and/or
excessive sweating, electrolyte disturbances, hyperthermia,
and exercise during fever. In patients with LQTS-1
swimming and diving should be discouraged because these
activities are well-known triggers for cardiac events [
Eligibility decision-making in SQTS
1. In asymptomatic phenotype-positive SQTS all sports are
]. Oral drugs (quinidine or sotalol to increase
the QTc interval) may be considered.
2. In symptomatic phenotype-positive SQTS—survivors
of aborted SCA, documented spontaneous sustained
VT—low intensity sports (Mitchell’s classification of
sports) may be considered. ICD implantation is
recommended and if there are no cardiac events for at least
3 months participation in low-moderate intensity sports
(Mitchell’s classification of sports) may be considered
3. In genotype-positive phenotype-negative SQTS
individuals with or without at least one first-degree family
member with SCD are allowed to participate in all sports.
4. All patients with SQTS should avoid dehydration and/or
excessive sweating, hyperthermia, and exercise during
fever. Hyperkalaemia, for instance, associated with
dehydration and/or excessive sweating should probably be
avoided because high extracellular potassium levels may
further shorten the QT interval.
Eligibility decision-making in CPVT
1. In asymptomatic phenotype-positive CPVT with
exercise-induced or emotionally initiated polymorphic VT
only low intensity sports (Mitchell’s classification of
sports) are allowed and β-blockers are recommended.
2. In symptomatic phenotype-positive CPVT
(exercise-induced recurrent syncope, aborted SCA, polymorphic VT
despite β-blockers, verapamil or flecainide) sports
participation is restricted to low intensity sports (Mitchell’s
classification of sports). If there are no ventricular
arrhythmic events during at least 3-month follow-up low
to moderate intensity sports (Mitchell’s classification of
sports) may be considered.
3. In genotype-positive phenotype-negative CPVT
β-blockers are to be considered. Those using β-blockers can be
allowed to participate in all sports with the advice to
avoid strenuous exercise and stressful circumstances.
4. All CPVT patients should avoid stressful environment
and strenuous exercise, dehydration and/or excessive
sweating, electrolyte disturbances, hyperthermia, and
exercise during fever.
Eligibility decision-making in Brugada syndrome
1. In asymptomatic BrS—i. e. spontaneous type 1 ECG—,
there is no restriction for sports participation. Ventricular
arrhythmia only on provocation with a sodium channel
blocker would not change this recommendation.
2. In symptomatic BrS (palpitations, dizziness) all sports
are allowed. If there is syncope or aborted SCA sports
participation is restricted and ICD implantation should
be considered. Resuming sports participation can be
allowed if there are no appropriate shocks during at least
3-month follow-up [
3. Genotype-positive—i. e. pathogenic SCN5a mutation—
phenotype-negative BrS with or without at least one
family member with SCA/SCD are allowed to participate in
4. All patients with BrS drugs that may aggravate the
disease (www.brugadadrugs.org) should avoid dehydration
and/or excessive sweating, electrolyte disturbances,
hyperthermia, and exercise during fever.
Eligibility decision-making in overlap syndromes
For patients with overlap syndromes the advices relating
to both disease entities (for example, LQTS and BrS) are
pertinent. We have mentioned that separately.
New research data should allow for the introduction of more
liberal eligibility decision-making for sports participation in
athletes with channelopathy. Eligibility decision-making in
channelopathy should involve the opinion of cardiologists
with expertise in these rare syndromes and, to date, cannot
be based on a presumed risk of pro-arrhythmia related to
exercise. Athletes—and their parents in case of a minor—are
entitled to detailed information about the risk of sport
participation and should be part of the shared decision-making
process to continue sports participation.
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