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/ Daily Fluctuations in Brugada Pattern (Type 1)
Daily Fluctuations in Brugada Pattern (Type 1)
It is known that
Brugada pattern (Type 1 or 2)
is unmasked on the
ECG during a fever
, and has
circadian fluctuation
.
Fever
(elevated temperature)
unmasks the Brugada pattern
on the
ECG
,
for example, a patient has at a temperature:
37°C normal ECG
and at
39°C
has the
Brugada pattern on the ECG.
Circadian fluctuation of the Brugada pattern
means,
that the pattern appears and disappears on the
ECG during the day
, for example, a patient has
normal ECG at 8:00 AM
and
at 4:00 PM
has the
Brugada pattern on the ECG.
Ajmaline test
is performed if the patient has
normal ECG
(or Brugada pattern Type 2)
and there is a high
suspicion of Brugada syndrome
based on the medical history,
for example, the patient had syncope and a family member suddenly died.
The Ajmaline test is used to
unmask the Brugada pattern (Type 1) on the ECG.
Flecainide is also used in place of ajmaline.
From the above, it can be concluded that
the diagnosis of the Brugada pattern on the ECG is underestimated.
On an occasional 12-lead ECG (e.g., during routine check-ups),
the Brugada pattern on the ECG may never be captured
in a patient.
ECG Holter monitoring
(24-hour) captures
Brugada pattern (Type 1) in 20% of patients
who have
normal ECG
and
the Brugada pattern is
unmasked only during the Ajmaline
(Flecainide)
test
The following study analyzes:
Circadian fluctuation of ECG Brugada pattern Type 1
during
24 hours
in patients with Brugada syndrome
using an
ECG Holter monitor
24-hour
12-lead
Study Results
According to the
ECG Holter monitoring
, the occurrence of
Brugada pattern Type 1 (BrP-1)
was defined as:
Persistent
(persisting >85% over 24 hours)
Intermittent
(persisting <85% over 24 hours)
Absent
(not present at all over 24 hours)
251 patients
with
Brugada syndrome (BrS)
75 (30%)
had
spontaneous
BrP-1 on the baseline ECG
9 (12%)
had
persistent
BrP-1 (ECG Holter monitoring)
43 (57%)
had
intermittent
BrP-1
23 (31%)
had
absent
BrP-1
176 (70%)
had
drug-induced BrP-1
(by Ajmaline or Flecainide)
35 (20%)
had
intermittent
BrP-1
141 (80%)
had
absent
BrP-1
Circadian occurrence of BrP-1
and heart rate in
4 phases of the day
:
00:00 – 06:00:
7%
(69±7/min.)
06:00 – 12:00:
9%
(63±13/min.)
12:00 – 18:00:
52%
(90±8/min.)
18:00 – 24:00:
32%
(82±11/min.)
ECG Holter monitoring captures
the
Brugada pattern in 20% of patients
who have the Brugada pattern
unmasked by Ajmaline/Flecainide
and have
normal baseline ECG
Patient Profile and Study Methodology
251 patients
with
Brugada syndrome (BrS)
BrS
was defined as
Brugada pattern Type 1 (BrP-1)
(spontaneous or induced).
33
were
symptomatic
(syncope, sudden cardiac death reversal).
Aged
15-46 years
(72% were male).
Enrolled between
2001-2013
(
Italy
),
followed for
38±26 months
since enrollment.
Each patient had at least
1 ECG Holter recording
ECG Holter monitoring
was
24-hour
and
12-lead
Leads were placed:
V1, V2 (2nd intercostal space)
V3, V4 (4th intercostal space)
V5, V6 (5th intercostal space - standard position)
Based on the
Holter ECG
recording, the
burden of BrP-1
was determined as:
Persistent
BrP-1 (persisting >85% over 24 hours)
Intermittent
BrP-1 (persisting <85% over 24 hours)
Absent
BrP-1 (not present at all over 24 hours)
Occurrence of Brugada pattern on ECG Holter
251 patients with BrS
(33 were symptomatic)
75 (30%)
had
spontaneous BrP-1
(captured on baseline ECG)
63 patients were asymptomatic
11
had a history of
syncope
1
patient had a
reversed sudden cardiac death
6 patients (6/75) had BrP-1 captured only during
fever
These patients did not have BrP-1 on ECG Holters or ECGs without fever
according to
ECG Holter monitoring
9 (12%)
had
persistent
BrP-1
43 (57%)
had
intermittent
BrP-1
23 (31%)
had
absent
BrP-1
176 (70%)
had
drug-induced BrP-1
(by Ajmaline/Flecainide)
154 patients were asymptomatic
21
had a history of
syncope
according to
ECG Holter monitoring
35 (20%)
had
intermittent
BrP-1
141 (80%)
had
absent
BrP-1
Occurrence of Brugada pattern and Symptomatology
251 patients
with Brugada syndrome
33 symptomatic
(syncope, aborted sudden cardiac death)
12 had BrP-1
on ECG Holter monitoring
218 asymptomatic
75 had BrP-1
on ECG Holter monitoring
Circadian Fluctuation of Brugada pattern
The occurrence of
Brugada pattern Type 1 (BrP-1)
during the
day
(24 hours) was analyzed
BrP-1
occurs most frequently in patients during the
12:00 - 18:00
time period
Circadian fluctuation of BrP-1
and heart rate in
4 phases of the day
:
24:00 – 06:00:
7%
(69±7/min.)
06:00 – 12:00:
9%
(63±13/min.)
12:00 – 18:00:
52%
(90±8/min.)
18:00 – 24:00:
32%
(82±11/min.)
