www.elsevier.com/locate/jelectrocard

Journal of Electrocard

Dynamic electrocardiographic changes after aborted sudden death

in a patient with Brugada syndrome and rate-dependent

right bundle branch block

Manlio F. Marquez, MDT, Abdo Bisteni, MD, Gustavo Medrano, MD, Alfredo De Micheli, MD,

Milton Guevara, MD, Pedro Iturralde, MD, Luis Colın, MD,

Antonio G. Hermosillo, MD, Manuel Cardenas, MDDepartment of Electrocardiology, Instituto Nacional de Cardiologıa bIgnacio Chavez Q, Tlalpan 14080, Mexico City, Mexico

Received 3 October 2004; revised 22 February 2005; accepted 1 March 2005

Abstract A 37-year-old man with Brugada syndrome and dynamic changes of the ST-segment morphology

0022-0736/$ – see fro

doi:10.1016/j.jelectroc

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observed after an episode of aborted sudden death is described. On admission, after 3 syncopal

episodes during nighttime, his electrocardiogram showed right bundle branch block (RBBB) with a

J-point elevation of 0.6 mV in lead V2. Changes observed in the following days included a diminished

J-point elevation and intermittent bsaddle-back Q type of morphology. During a previous 2-year follow-

up, intermittent, complete, acceleration-dependent RBBB was documented. Right ventricular

intracavitary tracings showed an RS pattern with a broad S wave in the unipolar electrogram; the

time of onset of intrinsic deflection in this electrogram was 60 milliseconds. To our knowledge, this is

the first report of an intracavitary demonstration of complete RBBB in Brugada syndrome.

D 2005 Elsevier Inc. All rights reserved.

Keywords: Brugada syndrome; Sudden cardiac death; Right bundle branch block; Ventricular fibrillation; Implantable

defibrillator

1. Introduction

Sudden cardiac death in healthy individuals with

structurally normal hearts and a characteristic morphology

of the QRS complex resembling a right bundle branch block

(RBBB) with elevation of the ST segment in V1 through V3

is known as Brugada syndrome (BrS) [1-3]. We describe a

patient with BrS, family history of BrS, and intermittent

complete RBBB, with transient exacerbation of RBBB and

ST-segment elevation after aborted sudden death.

2. Case report

A 37-year-old man was admitted in December 2002

because of 3 syncopal episodes during nighttime. Three of

nt matter D 2005 Elsevier Inc. All rights reserved.

ard.2005.03.004

author. Tel.: +52 55 5513 3740; fax: +52 55 5573

anliomarquez@yahoo.com (M.F. Marquez).

his relatives died suddenly at a young age, including one

with a Brugada-type electrocardiogram (ECG); another

relative had an implantable cardioverter/defibrillator (ICD)

implanted because of symptomatic BrS. Absence of

structural heart disease was confirmed by physical exami-

nation and echocardiogram.

Baseline 12-lead ECG revealed sinus bradycardia

(54 beats per minute) with a normal PR interval (0.20 sec-

onds) (Fig. 1). Electrocardiogram criteria for RBBB were

the following: (1) QRS interval (measured from the

beginning of the QRS complex to the J point) of 120 milli-

seconds in lead V1; (2) a slurred purely positive QRS

complexes in V1, V2, and aVR; (3) a slurred S wave in I,

aVL, and from V4 through V6 (left ventricular potential

variations); and, finally, (4) secondary T-wave changes in

V1, V2, and aVR. Contrary to common RBBB, the J point is

elevated in leads V1 (0.5 mV), V2 (0.6 mV), and V3 (0.2 mV),

and a negative deplacement of the J point is inscribed in left

precordial leads. As the J point is uncertain in leads V2 and

iology 38 (2005) 256–259

0.12 s

0.5 mV

J point

J point

I

II aVL

aVR

V2

V1

V5

III aVF V3 V6

V4

Fig. 1. Twelve-lead ECG showing complete RBBBwith persistent ST-segment elevation in leads V1 and V2. Arrow in the magnified second cardiac cycle in lead

V1 indicates the J point that is elevated by 0.5 mV. Horizontal arrow indicates the QRS interval (measured from the beginning of the R wave to the J point).

ANov 28th

CL = 1160

BNov 29th

CL = 1200

CDec 1st

CL = 1320

DDec 2nd

CL = 1360

* *

V1

V2

V31mV

1 seg

ig. 2. Leads V1 through V3 from admission after an aborted sudden death

) and serial ECGs from consecutive days after (B to D). Dynamic

hanges of the J-point and ST-segment elevations after admission can be

en. Notice the greater ST-segment elevation in lead V2 on admission

rrows) and the appearance of a saddle-back type of morphology on

llowing days (asterisks). All ECGs are from 1-strip electrocardiographs.

L indicates cycle length in milliseconds.

M.F. Marquez et al. / Journal of Electrocardiology 38 (2005) 256–259 257

V3, a vertical line (dotted) was inscribed from the J point in

lead V1, which is clearly separated from the descendent limb

of the RV wave.

The alterations observed at admission diminished

progressively over time. On the second day of hospital-

ization, the J point diminished in lead V2 (Fig. 2B). On

the fourth and fifth days, a bsaddle-backQ type of

morphology was found in the same lead (Fig. 2C and D).

An ICD was implanted and he was discharged without

drug therapy. One month later, he had a spontaneous

ventricular fibrillation (VF) successfully terminated by

the ICD.

During a previous follow-up, a routine treadmill

exercise testing was found to be normal, late potentials

were present in a signal-averaged ECG, and Holter

monitoring showed intermittent RBBB (Fig. 3). In the

absence of RBBB, a type II (saddle-back) ST-segment

elevation was seen. Notice the close relationship between

the appearance of RBBB and heart rate: as soon as heart

rate increases, the RBBB appears (Fig. 3A). Inversely, as

the heart rate slows, aberration disappears (Fig. 3B). At

an electrophysiologic study performed in October 2000,

intracavitary intervals were as follows: AH 102 milli-

seconds and HV 75 milliseconds (cycle length 973 milli-

seconds). Decremental right ventricular pacing at 2 sites,

with a protocol of 2 cycle lengths and up to 3 extra-

stimuli, with and without isoproterenol, had been unable

F

(A

c

se

(a

fo

C

A

B

1 mV

1280 ms 1360 ms

#30 49 Ipm 01:33:24

1 mV

840 ms1360 ms

#54 57 Ipm 03:54:27 Salva EVs

Revisión del Médico`

Fig. 3. Routine Holter recording of leads MCL1 (superior) and MCL5 (inferior), revealing an acceleration-dependent RBBB. A, Numbers indicate the intervals

between a first beat with a saddle-back type of morphology and the onset of advanced RBBB (1280 milliseconds) and between abnormally conducted beats

(1360 milliseconds). B, Numbers indicate the intervals between both abnormally and normally conducted beats (860 and 1360 milliseconds, respectively).

M.F. Marquez et al. / Journal of Electrocardiology 38 (2005) 256–259258

to induce ventricular tachycardia or VF. Right ventricle

intracavitary tracings showed an RS pattern with a broad

S wave; the time of onset of intrinsic deflection (TOID)

in this unipolar electrogram was 60 milliseconds (Fig. 4).

3. Discussion

This patient had typical BrS with family history,

recurrent syncope, late potentials, prolonged HV interval,

and eventual documentation of spontaneous VF. Several

ECG aspects of this case deserve comment: the documen-

Fig. 4. Simultaneous recordings from surface ECG leads (I, aVF, and V1) and ape

apex of the right ventricle (Apex Un) reveals an RS pattern with a broad S wave

These findings are typical of an advanced RBBB.

tation of advanced RBBB, the acceleration-dependent

nature of the RBBB, and the transient exacerbation of the

ST-segment elevation after aborted sudden death.

Electrocardiographic characteristics of the BrS include

depolarization and repolarization abnormalities. The pres-

ence of true RBBB is a controversial issue since the

original description of BrS. In the first 8 cases reported by

Brugada and Brugada [1], only 4 fulfilled the ECG criteria

for complete RBBB (patients 1, 2, 3, and 6). The rest had

an RBBB-like pattern. In the cases of Martini et al [4],

now considered to be BrS, only 1 of the patients showed

x of the right ventricle. Magnified intracardiac unipolar recording from the

. The TOID (arrow) in this intracavitary lead is delayed (60 milliseconds).

M.F. Marquez et al. / Journal of Electrocardiology 38 (2005) 256–259 259

complete RBBB (patient 1). Now it is accepted that in

patients with an RBBB-like pattern, the high-takeoff ST

segment may mimic an RBBB; however, the absence of S

waves in the left lateral leads precludes the presence of

right ventricular conduction delay [5]. The ECG charac-

teristic of BrS with true RBBB has been scarcely described

[6]. Repolarization abnormalities in BrS are commonly

reported as ST-segment elevation in 2 basic types, a

bcoved Q type (the only diagnostic) and a saddle-back type

[7]. In BrS with true RBBB, repolarization abnormalities

always include J-point and ST-segment elevations, with

or without J wave [1,4,8,9]. These findings are not seen

in isolated RBBB [10]. Our case had a true advanced

RBBB as demonstrated by intracavitary tracings with an

RS pattern, a broad S wave, and delayed TOID (N50

milliseconds) in the unipolar right ventricular electro-

gram [10-13]. This is the first irrefutable demonstration

of a true RBBB in BrS. This confirmation is not

possible without intracavitary recordings.

The spontaneous changes of the morphology of

ST segment in BrS have been described before in isolated

cases without advanced RBBB [14]. In the case herein

presented, spontaneous dynamic changes of QRS com-

plexes were observed during routine Holter monitoring

because of a functional, acceleration-dependent RBBB.

Aberration appears with the gradual acceleration of sinus

rhythm. When the cardiac cycle shortens until it becomes

shorter than the refractory period of the right bundle branch,

aberrant conduction develops [15]. The critical rate at which

RBBB develops in this case is 46 beats per minute.

Tachycardia-dependent RBBB was found to be relative, as

aberration develops with faster heart rates [15].

Dynamic changes of ST segment and J waves after

VF have been described before but only in patients without

advanced RBBB [16,17]. Similar to previous case reports,

exacerbation of the ST-segment elevation was observed in

our case after aborted sudden death. These findings could be

explained by a larger reduction of action potential amplitude

and phase 1 bdome Q in right ventricular epicardium (where

Ito is more prominent) [18].

Although BrS is considered to occur in structural normal

hearts, the presence of prolonged HV intervals and RBBB

suggests minor structural changes that are not detected by

conventional diagnostic tests. Actually, Takagi et al [19] had

described localized right ventricular morphological abnor-

malities (hypokinesis, akinesis, or focal aneurysmal changes

in right ventricular outflow tract or inferior wall) detected by

electron-beam computed tomography in 21 (81%) of

26 patients with BrS. Echocardiography and right ventricu-

lography demonstrated hypokinesis only in 2 (8%) patients.

In contrast, only 2 (9%) control subjects had hypokinesis

detected by electron-beam computed tomography but it was

localized to the right ventricular apex. The significance of

these findings is still under discussion [20].

In conclusion, ECG classification of patients with BrS

should include those with complete RBBB and those with

an RBBB-like pattern. Both can be subclassified into coved

or saddle-back types.

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