Early repolarization (ER), consisting of a J-point elevation, notching or slurring of the terminal portion of the R wave (J wave), and tall/symmetric T wave, is a common finding on the 12-lead electrocardiogram. For decades, it has been considered as benign, barring sporadic case reports and basic electrophysiology research that suggested a critical role of the J wave in the pathogenesis of idiopathic ventricular fibrillation (VF). In 2007-2008, a high prevalence of ER in patients with idiopathic VF was reported and subsequent studies reinforced the results. This PPT describes the current state of knowledge concerning ER syndrome associated with sudden cardiac death.
Dr Ramachandra/Dr AN Patnaik
Ventricular repolarisation is defined by the
interval from the end of the QRS complex to the
end of the T wave on surface ECG= J waves+ T
+U waves+ ST segment. This phase of the cardiac
cycle is subject to intrinsic and extrinsic
influences; thereby, alterations noted in this
phase can have Ventricular arrhythmias
1. ST-segment elevation
a. Early repolarisation(elevated J point)
2. QT-interval abnormalities
a. Short QT syndromes
b. Long QT syndromes
J waves are found at the junction of the QRS
complex and beginning of ST segment
Early repolarisation syndrome is an ECG finding
consistent with J-point elevation(0.1-Mv) and
prominent T waves usually associated with ST-
segment elevation in 2 contiguous leads
It is not “normal variant” but linked to SCD and
2-5% general incidence.
hypervagotonia, spinal cord injuries.
b.Cardiac :Prinzmetal angina, acute transmural
ischemia, and Brugada syndrome.
Incidence =2%-5%, most commonly seen in
young, athletic, male and with stringent
criterion (0.2-mV J-point elevation in 2
contiguous leads) drops the prevalence in the
general population to 0.3%-0.8%.
ERP - increased risk of SCD is associated with J-
point and ST-segment elevations limited to
inferior and lateral leads on surface ECG
31% of patients with idiopathic VF
More at night in patients with VF, consistent
with increased night-time vagal tone
Increased transmural dispersion of refractoriness
in Phase 1-2 of the APD
Inferior vs lateral leads/magnitude of J-point
elevation (0.2 mV) are associated with a high
risk of SCD(RR=2.98;95% CI=1.85-4.92; P 0.001)
EPS is unclear in risk stratification of such
patients given low sensitivity (40%) and rate of
GENETICS OF EARLY
Phase 2 reentry likely mechanism of VF =
increase in the activity of ITO, IKATP(KCNJ8),
16% of ERPS and idiopathic VF had F/H of SCD
Reversible causes of early
repolarization pattern on ECG must
be excluded, namely acute schemia,
hypothermia, hypercalcemia, and
irreversible spinal cord injuries and
sympathetic nerve damage
Vasospastic angina Mostly normal CAG
Brugada syndrome limited to V1-V3 leads,
Early repolarization pattern INF/Lateral leads and Ajmaline
injection attenuates ERP.
CLASSIFICATION HAS BEEN PROPOSED
FOR STRATIFYING ARRHYTHMIC RISK
IN INDIVIDUALS OF ERP PATTERN
Type 1: The ERP only in the lateral leads=
benign outcome=young, healthy men.
Type 2: ERP = inferior or inferolateral leads and
is associated with moderate risk of Arrhythmic
SCD, especially in individuals with syncope and
personal or F/H of SCD.
Type 3: ERP = globally =inferior+ lateral+Rt
precordial leads /highest risk of malignant
ventricular arrhythmias, VT/VF storms, and
Isoproterenol are useful.amiodarone, -blockers,
and flecainide,are ineffective
ICD:Usuful for both for primary and secondary
prevention of SCD along with Quinidine as
SUMMARY OF EARLY
ERP pattern on ECG is not always a “benign
Careful assessment and close follow-up of H/O
A F/H of SCD is high risk.
Not a sensitive phenotypical marker for SCD,
per se, but indicates a genetic predisposition
toward the development of the same
Notched QRS complexes as markers of SCD.
RBBB, ST-segment elevation and T inversion.
mutations in at least 8 separate genes encoding
the sodium, potassium, and calcium channels
involved in the generation of cardiac myocyte
sudden cardiac death in up to 20%
(12/10,000) in Southeast Asia and less frequent
cases (5/10,000) in the Western hemisphere
bangungut in Philippines, lai tai in Thailand,
most common cause of SCD in young males in
3 DISTINCT ECG PATTERNS (V1-V3)
Type 1 pattern is characterized by J-point or
coved ST-segment elevation 2 mm followed by a
negative T wave.
Type 2 pattern is characterized by J-point or
saddle-shaped St segment elevation 2 mm
followed by positive or biphasic T wave.
Type 3 pattern is characterized by coved or
saddle-shaped ST-segment elevation 1 mm.
A positive response to a sodium channel blocker
is characterized by the following:
1. Type 1 coving ST-segment elevation in
leadsV1-V2 or V3 (Fig 6).
2. Conversion of type 2 or type 3 to type 1
GENETICS OF BRUGADA
autosomal-dominant, heterogeneous genetic
disorder ,variable penetrance
Mutation(300 mutations) at the alpha-subunit of
the sodium channel (SCNA5),K-channel(ITO),Ca
loss of function of the sodium channel, is the
most common genetic abnormality observed in up
to 20% patients with BS
Spontaneous and inducible AF is noted in up to
20% of with biphasic P waves.
Hallmark -heterogeneous shortening of the APD
in the RV epicardium
A decrease in the inward Na and Ca currents
coupled with a strong outward K current (ITO)
toward the end of the phase 1 action potential
results in the accentuation of the action potential
notch and loss of action potential dome in some of
the epicardium cells
Brugada ECG phenotype is a direct
mmanifestation of the imbalance in ion currents
during the latter portion of Phase 1 and
prolonged phase 2 causing long APD.
electrical heterogeneity = electrical gradient
Phase 2 reentry =of VT/VF
Predominance ITO in the epicardium, t
repolarization in the epicardial cells recedes that
in the M-cells (midmyocardial) and the
endocardial cells, is responsible for the ST-
segment elevation observed in the right
Precordial leads in BS
The shortening of the APD secondary to
enhanced vagal activity in association with Phase
3 afterdepolarizations may be responsible for the
development of VF, a clinical scenario consistent
with nocturnal deaths.
2 following groups:
1. Asymptomatic with Brugada ECG.
2. Symptomatic with Brugada ECG
ECG remains the cornerstone
The proposed clinical criteria for the diagnosis
1. Syncope with or without warning.
3. Nocturnal agonal respiration.
4. Family history of sudden cardiac death 40 years.
5. Brugada type 1 ECG in family member.
6. Documented VT/VF.
Na channel-blocking - diagnostic /prognostic to
reveal a concealed form of BS or convert type 2 or
type 3 patterns to Brugada type 1 ECG.
Ajmaline, Procainamide, Flecainide, and
Propafenone- challenge should be considered
positive only when a type 1 ECG pattern (coved
ST-segment elevation 2 mm with T-wave
inversion in V1-V2 or V3)=8% event rate
(ventricular arrhythmias, lethal and nonlethal)
at 33 39 months of follow-up (hazard ratio 2.5)
abnormal PES (inducible VT/VF) has a positive
predictive value of 50% and a negative predictive
value of 46% and is associated with increased
risk of sudden cardiac death
Asymptomatic individuals with provoked type 1
ECG post-drug challenge with a negative
electrical study (PES) have a good prognosis
ICD remains the most effective treatment
20%-35% of inappropriate ICD shocks—most
likely secondary to SVT(ST/ AF)
Drugs that modify the outward Na current in
phase like Quinidine, an ITO blocker, is effective
in ECG pattern normalization as well as in
suppression of spontaneous and inducible VT/VF
or Ca channel function promoter like
Isoproteronal is useful.
RFA is used less frequent
Atrial fibrillation is treated with
BB,Disopyramide and Quinidine.
SHORT QT SYNDROME
First description in 2000
Five genes encoding the potassium and calcium
channels involved in generation of myocardial
cell action potential= Gain of function
The gold standard for diagnosis remains a short
QT interval on surface ECG
Only 27% of the patients with confirmed SQTS
who underwent testing could be genetically
The prevalence of SQTS (QTc 340 ms) in the
general population is about 0.5%, making it a
The classic ECG: QTc interval of 360 ms, short ST
segment, and tall T waves.
It is extremely crucial to record the heart rate at the
time of QTc calculation, as the overcorrection of QTc
and T-wave amplitude during bradycardia is well-
known, the latter of which also increases at slower
confirmed SQTS have a flat QTc/R-R interval
relationship, whereby the QTc interval fails to
prolong at slower heart rates and remains in the low
range (ie, 360 ms at heart rates greater than 80
Recording ECG at different heart rates with varying
QTc intervals is helpful in separating a patient with
“true SQTS” from a flat QTc/R-R interval response to
GOLLOB MH, REDPATH CJ, ROBERTS JD. THE SHORT
QT SYNDROME: PROPOSED DIAGNOSTIC CRITERIA. J
AM COLL CARDIOL 2011;57:802-12
GENETICS OF SHORT QT
mutations in 5 different genes encoding the
potassium and calcium channels, gain of function
involving the potassium channels is the major
abnormality in the first 3 gene mutations
SQTS1-KCNH2 (hERG),=gain in function Ikr= ↓
APD and ↓ affinity to IKr blockers.
SQTS2 -KCNQ1= gain in function IKs= clinically
associated with AF with SVR and SCD.
SQTS3-KCNI2,= gain in Iki.
CACNA1C and CACNB2b mutation for SQTS4
only 27% confirmed SQTS genetically classified
Hypervagotonia, digitalis toxicity, hyperthermia
Ambulatory ECG recording is helpful not only to
demonstrate a flat QTc/R-R,VT/VF/AF
Electrophysiologic study-short refractory periods
(140-200 ms) in the atrium and ventricles during
programmed stimulation helps confirm the
underlying diagnosis and vulnerability of such
patients toward spontaneous polymorphic VT/VF
PMVT/VF /AF is inducible in 60% in confirmed
SQTS. sensitivity of inducing VF with hx of
SCD 40% ,hence EPS is not final for Rx decision.
To date, the largest database of patients in the world with confirmed
SQTS comprises less than 60 patients.93 The most common first
is cardiac arrest, noted in 33% of the patients, with more than 60%
having symptomatic history at the time of initial diagnosis. The initial
of presentation varies, ranging from 8 months to 70 years, with 80% of
patients having a personal or family history of sudden cardiac death.
second most common presentation is syncope, noted in about 13% of
patients, with the presumptive diagnosis of self-terminating VT episodes
as the most likely cause of syncopal episodes. Isolated episodes of AF or
atrial flutter, especially in young patients, are noted in about 17% of
Therapy options include ICD implant. Use of
hydroquinidine is recommended to suppress
recurrent VT/VF and also in patients deemed
unsuitable for or who refuse an ICD implant
LONG QT SYNDROME
gold standard for DX= ECG
Exclude severe hypocalcemia/ hypokalemia,
hypothermia/acute ischemia/CNS events, and
12-lead ECG -the gold standard
Bazett’s formula- most commonly used
Up to 460ms in women, 440ms in men –normal
An average of at least 5 cardiac cycles, in II, V5,
and V6, and the longest QT any of these leads
Biphasic /notched/variations in amplitude and
polarity (T-wave alternans)- is most commonly
observed during exercise or emotional or physical
stress and is a precursor to the development of
polymorphic VT - regarded as a risk factor for
sudden cardiac arrest and malignant VT.
PATTERNS IN 3 TYPES OF LONG QT
Cardiac arrest survivors.
On -blockers with recurrent syncope.
Age 5 years with syncope.
High-risk asymptomatic patients (J-LNS, marked
QTc prolongation [550 ms], men with LQTS3,
patients with 2 mutations who remain symptomatic
despite -blocker therapy)
Combined=BB+ICD for daryprevention
Surgical -Left cardiac sympathetic denervation
=removal of the first 4 thoracic ganglia
Many have a molecular basis known &
many will be discovered