Spontaneous Right Ventricular Out� ow Tract Tachycardia ina Patient with Brugada Syndrome

MASAHIRO OGAWA, M.D., KOICHIRO KUMAGAI, M.D., and KEIJIRO SAKU, M.D.

From the Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan

RVOT Tachycardia in Brugada Syndrome. We report the case of a 28-year-old man with nostructural heart disease, who exhibited clearly augmented ST segment elevation in the right precordialleads, followed by induction of spontaneous right ventricular out� ow tract tachycardia with intravenousadministration of Class IA antiarrhythmic drugs. The electrophysiologic mechanism of this tachycardiawas thought to be triggered activity due to delayed afterdepolarizations. Due to the existence of substratesthat were similar to Brugada syndrome combined with right ventricular out� ow tract tachycardia, thiscase may represent a subtype of Brugada syndrome. (J Cardiovasc Electrophysiol, Vol. 12, pp. 838-840, July2001)

right ventricular out�ow tract tachycardia, class IA antiarrhythmic drugs, Brugada syndrome

Introduction

In 1992, Brugada and Brugada1 reported a syndromecharacterized by idiopathic ventricular � brillation withright bundle branch block (RBBB) and ST segment ele-vation in the right precordial leads. Brugada syndromewas considered to be a primary electrical disease, andmutations in the cardiac sodium channel gene SCN5Awere identi� ed in some patients with Brugada syndrome.2

The characteristic feature of Brugada syndrome was re-ported to be the appearance of augmented ST segmentelevation in the right precordial leads with administrationof ajmaline, disopyramide, and procainamide.3 -5 How-ever, spontaneous sustained monomorphic ventriculartachycardia is rarely induced by administering thesedrugs. We report the case of Brugada syndrome in apatient who exhibited spontaneous right ventricular out-� ow tract (RVOT) tachycardia induced by intravenousadministration of class IA antiarrhythmic drugs (procain-amide and disopyramide).

Case Report

A 28-year-old man was admitted to the hospital due tosevere palpitation and fainting while playing basketball. Hehad occasional episodes of palpitation and fainting for sev-eral years. On examination, the 12-lead ECG showed a heartrate of 220 beats/min, right-axis deviation, and left bundlebranch block-type sustained monomorphic ventriculartachycardia (Fig. 1). He was given 600 mg of procainamideintravenously, without signi� cant improvement. Subsequentintravenous administration of lidocaine 50 mg terminatedthe sustained monomorphic ventricular tachycardia, but theECG showed an augmented ST segment elevation in theright precordial leads (Fig. 2). ST segment elevationin the right precordial leads and incomplete RBBB were

found on the resting ECG without administration of anydrug (Fig. 3).

The patient had no family history of ventricular tachycar-dia or sudden cardiac death, but his father’s resting ECGshowed similar changes, including ST segment elevation in theright precordial leads and incomplete RBBB. Physical exami-nation and laboratory � ndings showed no abnormality. Echo-cardiography was normal, and coronary angiography did notshow any stenosis. No spasm was induced after coronary in-fusion of acetylcholine. Nothing unusual was found during thegeneral cardiovascular examination; therefore, he was postu-lated to have an idiopathic ventricular tachycardia with nostructural cardiovascular disorder. Neither changes of ST seg-ment level in the right precordial leads nor induction of pre-mature ventricular complexes or sustained monomorphic ven-tricular tachycardia was observed in the drug loading test withintravenous administration of isoproterenol 2 m g or epineph-rine 5 m g. However, with intravenous administration of pro-cainamide 300 mg, ST segment elevation in the right precor-dial leads was clearly augmented, followed by induction ofspontaneous sustained monomorphic ventricular tachycardia(Fig. 4). An identical drug loading test several days laterreproduced this observation. The sustained monomorphic ven-tricular tachycardia was induced by intravenous administra-tion of disopyramide 100 mg but was terminated by verapamilor propranolol.

During electrophysiologic study (both control and iso-proterenol loading), neither sustained monomorphic ven-tricular tachycardia nor ventricular � brillation inductionwas observed after delivery of three consecutive extra-stimuli or burst stimulation from the right ventricular apexor out� ow tract. However, spontaneous sustained monomor-phic ventricular tachycardia was induced by intravenousadministration of procainamide 300 mg. After drug admin-istration, it was possible to induce and terminate the sus-tained monomorphic ventricular tachycardia by ventricularpacing. No entrainment was observed by ventricular pacingduring sustained monomorphic ventricular tachycardia. Adirect relationship was observed between the coupling in-terval from the last basic stimulation to the extrastimulationand the interval from the extrastimulation to the � rst ven-tricular excitation of sustained monomorphic ventriculartachycardia. Based on these � ndings, it was thought that themechanism of the sustained monomorphic ventriculartachycardia might be triggered activity. Radiofrequencycatheter ablation was performed, directed by the earliest

Address for correspondence: Masahiro Ogawa, M.D., Department of Car-diology, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jo-nan-ku, Fukuoka 814-0180, Japan. Fax: 81-92-865-2692; E-mail:ogawamas@kc4.so-net.ne.jp

Manuscript received 26 March 2001; Accepted for publication 18 April2001.

838 Reprinted with permission fromJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Volume 12, No. 7, July 2001Copyright ©2001 by Futura Publishing Company, Inc., Armonk, NY 10504-0418

potential site during sustained monomorphic ventriculartachycardia and the pace map during sinus rhythm in thevicinity of the RVOT. After ablation, no induction of sus-tained monomorphic ventricular tachycardia was observed,even with intravenous administration of procainamide 600mg. There were no recurrences of ventricular tachycardiaduring 32-month follow-up.

Discussion

Spontaneous sustained monomorphic ventricular tachy-cardia is rarely induced by intravenous administration ofClass IA antiarrhythmic drugs (procainamide and dis-opyramide). Bermudez et al.6 reported the occurrence ofsustained monomorphic ventricular tachycardia with a mor-

phology different than RVOT tachycardia, with spontane-ous onset induced by administration of ajmaline. They con-sidered that the mechanism might be related to increasedinhomogeneity of repolarization. Shimada et al.7 reportedthat sustained monomorphic ventricular tachycardia withleft bundle branch block morphology was induced by ap-plication of a single extrastimulus from the right ventricularapex during isoproterenol infusion. In our present case,RVOT tachycardia was never induced by programmed ven-tricular stimulation during baseline or isoproterenol loading.However, after intravenous administration of Class IA an-tiarrhythmic drugs, spontaneous RVOT tachycardia wasinduced and the electrophysiologic characteristics of sus-

Figure 1. Twelve-lead ECG showingright-axis deviation and left bundlebranch block-type sustained monomor-phic ventricular tachycardia (220beats/min).

Figure 2. Immediately after terminationof the sustained monomorphic ventricu-lar tachycardia, the 12-lead ECGshowed augmented ST segment eleva-tion in the right precordial leads (V1,V2 5 coved type; V3 5 saddle-backtype).

Ogawa et al. RVOT Tachycardia in Brugada Syndrome 839

tained monomorphic ventricular tachycardia were consis-tent with triggered activity due to delayed afterdepolariza-tions. Conventionally, Class IA antiarrhythmic drugsusually are effective for treatment of idiopathic RVOTtachycardia.8 To our knowledge, there is no report of spon-taneous RVOT tachycardia induced by administration ofClass IA antiarrhythmic drugs. Accordingly, we considerthat there might be relationship between ST segment eleva-tion in the right precordial leads and induction of RVOTtachycardia by intravenous administration of Class IA an-tiarrhythmic drugs. This case may represent a subtype ofBrugada syndrome.

References

1. Brugada P, Brugada J: Right bundle branch block, persistent STsegment elevation and sudden cardiac death: A distinct clinical andelectrocardiographic syndrome. A multicenter report. J Am Coll Car-diol 1992;20:1391-1396.

2. Chen Q, Kirsch GE, Zhang D, Brugada R, Brugada J, Brugada P,Potenza D, Moya A, Borggrefe M, Breithardt G, Ortiz-Lopez R, WangZ, Antzelevitch C, O’ Brien RE, Schulze-Bahr E, Keating MT, TowbinJA, Wang Q: Genetic basis and molecular mechanism for idiopathicventricular � brillation. Nature 1998;392:293-296.

3. Miyazaki T, Mitamura H, Miyoshi S, Soejima K, Aizawa Y, Ogawa S:Autonomic and antiarrhythmic drug modulation of ST segment eleva-tion in patients with Brugada syndrome. J Am Coll Cardiol 1996;27:1061-1070.

4. Brugada J, Brugada P: Further characterization of the syndrome ofright bundle branch block, ST segment elevation, and sudden cardiacdeath. J Cardiovasc Electrophysiol 1997;8:325-331.

5. Brugada R, Brugada J, Antzelevitch C, Kirsch GE, Potenza D, TowbinJA, Brugada P: Sodium channel blockers identify risk for sudden deathin patients with ST-segment elevation and right bundle branch blockbut structurally normal hearts. Circulation 2000;101:510-515.

6. Bermudez EP, Garcia-Alberola A, Sanchez JM, Munoz JJS, ChavarriMV: Spontaneous sustained monomorphic ventricular tachycardia af-ter administration of ajmaline in a patient with Brugada syndrome.PACE 2000;23:407-409.

7. Shimada M, Miyazaki T, Miyoshi S, Soejima K, Hori S, Mitamura H,Ogawa S: Sustained monomorphic ventricular tachycardia in a patientwith Brugada syndrome. Jpn Circ J 1996;60:364-370.

8. Lerman BB, Stein KM, Markowitz SM: Idiopathic right ventricularout� ow tract tachycardia: A clinical approach. PACE 1996;19:2120-2137.

Figure 3. Twelve-lead ECG showingsinus rhythm without administration ofany drug. Note the incomplete rightbundle branch block and ST segmentelevation in the right precordial leads.

Figure 4. Initiation of right ventricular out� ow tract (RVOT) tachycardiaby intravenous administration of procainamide 300 mg. ST segment ele-vation clearly appeared in the right precordial leads (V1, V2 5 coved type;V3 5 saddle-back type) compared with control, followed by reproducibleinduction of repetitive and sustained RVOT tachycardia.

840 Journal of Cardiovascular Electrophysiology Vol. 12, No. 7, July 2001