Arrhythmogenic right ventricular cardiomyopathy associated ventricular tachycardia misdiagnosed as idiopathic right ventricular outflow tract origin and its management

doi:10.4236/crcm.2013.28121

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Vol.2, No.8, 460-462 (2013) Case Reports in Clinical Medicine

http://dx.doi.org/10.4236/crcm.2013.28121

Arrhythmogenic right ventricular cardiomyopathy

associated ventricular tachycardia misdiagnosed as

idiopathic right ventricular outflow tract origin and its

management

Xiangmin Shi*, Yutang Wang, Zhaoliang Shan

Department of Cardiology, The General Hospital of People’s Liberation Army, Beijing, China;

*Corresponding Author: [email protected]

Received 25 June 2013; revised 23 July 2013; accepted 20 August 2013

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

Arrhythmogenic right ventricular cardiomyopa-

thy/dysplasia (ARVC/D) is an autosomal domi-

nant genetic form of cardiomyopathy (CM), which

primarily affects the right ventricle (RV) and re-

sults in life threatening ventricular arrhythmias

and sudden cardiac death (SCD). Diagnosis is

difficult due to the broad spectrum of phenol-

typic variations, especially in the early stage.

Clinical suspicion should be raised in the setting

of refractory ventricular tachycardia originating

from the RV, and the final diagnosis could be

made based on the combination of electrocar-

diography, echocardiography, cardiac magnetic

resonance imaging (CMRI) and myocardial bi-

opsy. Implantable cardioverter-defibrillator (ICD)

implantation is an effective option for the treat-

ment of ARVC.

Keywords: Arrhythmogeni c Right Ventricular

Cardiomyopathy; Ventricular Ta chycardia; Cardi ac

Magnetic Resonance Imaging

1. INTRODUCTION

Arrhythm ogenic right ventricul ar cardiom yopathy (ARVC )

is one of the major causes of recurrent ventricular tachy-

cardia (VT) and sudden cardiac death in young people.

QRS morphology of VT and abnormalities of precordial

leads in sinus rhythm, in association with echocardi-

ography (UCG) and cardiac magnetic resonance imaging

(CMR), play an important role in early diagnosis of

ARVC. Presented herein is a 25-year-old male soldier

who suffered from recurrent episodes of palpitation and

presyncope due to VT, which resembled that of idio-

pathic right ventricular outflow tract (RVOT) origin, di-

agnosed as idiopathic RVOT VT in the presence of

echocardiographic normal heart and received oral ad-

ministration of metoprolol which eventually proved to be

ineffective. Meanwhile, surface 12 leads ECG indicated

persistent T wave inversion in V1-V4, which was sug-

gestive of ARVC, and following CMR scan confirmed

the diagnosis, and subsequently the patient was treated

with implantable cardioverter defibrillator (ICD).

2. CASE REPORT

A 25-year old male soldier without significant structural

heart disease and past medical therapy as well as family

history of sudden death, complained of recent onset of

recurrent palpitation and presyncope. Documented ECG

in local clinic revealed VT of left bundle branch block

(LBBB) morthology with a inferior axis (Figure 1(b)),

which was similar to VT arising from RVOT. Physical

examination and routine laboratory tests, including ESR,

CRP, cardiac-specific enzymes, D-dimer and serum elec-

trolytes, were within normal limits. ECG indicated Rs

pattern of QRS complex of normal width in lead V1-V3

and T wave inv er s ion in V1-V 4 ( Figure 1(a)), no epsilon

wave was seen. Firstly ARVC was suspected, however,

UCG ruled out the possibility in the setting of structur-

ally normal left and right ventricular. The patient was

primarily diagnosed as idiopathic RVOT-VT and rec-

ommended the radiofrequency ablation therapy, which

was declined by him latterly. In the following several

weeks, oral administration of metoprolol (25 mg, bid)

was prescribed to prevent the occurrence of ventricular

arrhythmia, however, he still complained frequent epi-

sode of palpitation with presyncope, and consequently

refered for hospitalization for further examin ation.

During hospitalization, repeated trans-thoracic UCG

X. M. Shi et al. / Case Rep orts in Clinical Med icine 2 (2013) 460-462 461

(a)

(b)

Figure 1. (a) ECG of sinus rhythm revealing T wave inversion

in lead V1-V4; (b) ECG documented ventricular tachycardia

with LBBB morphology and a inferior axis similar to idiopathic

RVOT-VT.

revealed normal dimension, thickness and ejection frac-

tion of dual ventricular chamber. He was still suspected

the diagnosis of A RVC due to the surface ECG findings,

Gadolinium-enhanced cardiac MRI (CMR) scan was

subsequently arranged for detailed assessment, which

revealed abnormality of right ventricular including focal

enlargement, akinetic motion with aneurysm of the free

wall (Figure 2), these findings were strongly suggestive

of ARV C.

Based on those clinical features, the soldier fulfilled

the clinical criteria for ARVC and ICD was implanted

consequently, during the follow-up, we observed ICD

treatment in the presence of VT, including anti-tachy-

cardia pacing (ATP) and shock delivery, the patient no

longer suffered presyncope.

3. DISCUSSION

ARVC is characterized by the progressive replacement

of right ventricular myocytes by fibrous or fibro-fatty

tissue which results in an area of slow conduction and

dispersion of refractoriness [1], leading to reentrant ven-

tricular tachyarrhythmia. Mutations in the desmosomal

proteins of the myocardium are believed to be attribut-

able to the pathog enesis of ARVC. However, the d iagno-

sis of ARVC is challenging due to its wide range of

manifestations ranging from an absence of symptoms to

cardiac arrest. Currently the 1994 Task Force Criteria

Figure 2. CMR scan indicating focal enlargement, akinetic

motion with aneurysm (arrow indicated) localized in the free

wall of right ventricular. Left: enhenced-CMR imaging; right:

non enhenced-CMR imaging.

(TFC) has been the frequently used method for the diag-

nosis of ARVC based on electrocardiographic, structural,

functional abnormalities and family history [2].

The patient firstly referred to our hospital with recur-

rent VT of LBBB morphology and an inferior axis, pre-

senting as an R wave in II, III and AVF leads; QS wave

in AVR and AVR leads with precordial R/S transition in

V4, which was typical features of idiopathic VT arising

from the RVOT. It is commonly believed that patients

with RVOT-VT rarely suffer from underlying structural

heart disease, and the prognosis is satisfactory. Because

of no abnormality detected by the first UCG screening,

the diagnosis of idiopathic RVOT-VT was made even

when ARVC was highly suspected in the presence of T

wave inversion in V1-V4 leads, which were characteris-

tic of ARVC. Because RVOT-VT can be adrenergically

mediated, β-receptor antagonist, metoprolol (25 mg,

twice daily), was orally administrated, however which

could not effectively prevent recurrence of VT. Some

studies have suggested that patients with ARVC could

manifest the same VT pattern as idiopathic RVOT-VT [3]

and T wave inversion (TWI) in V1-V3 of sinus rhythm,

which has a high sensitivity and specificity in the dis-

crimination of ARVC from RVOT [4]. Discrimination

between these 2 entities is critical due to different prog-

noses and therapeutic options. TWI in V1-V3 has been

reported in 36% to 96% of ARVC patients [5] and has

been proposed as a major criterion for the diagnosis of

ARVC [6].

UCG is commonly used as a screening tool for the di-

agnosis of ARVC, and most affected areas of RV involve

the apex, the outflow tract and posterior wall, which are

known as “triangle of dysplasia” and can be detected by

UCG. In this case, twice UCG scan revealed structural

and functional normal heart, leading to the misdiagnosis

of idiopathic RVOT-VT. Focal minor abnormality within

the right ventricle in the early stage of ARVC not de-

tected by UCG could be the major reason, which limited

the accuracy and utility of UCG. Compared with UCG,

X. M. Shi et al. / Case Rep orts in Clinical Med icine 2 (2013) 460-462

462

CMR has been proved to more precisely assess the re-

gional, morphological abnormalities and potentially the

presence of fatty infiltration. The patient referred to

CMR imaging and was found localized aneurysm and

dilation of the right ventricular free wall, which sup-

ported the diagnosis of ARVC. For patients with possible

ARVC who do not meet criteria of TFC, CMR may re-

veal the typical features and alter the subsequent treat-

ment [7,8]. It was reported that TWI of right precordial

leads usually occurred in patients with extensive right

ventricular involvement [9], however, the soldier has

pronounced TWI in the setting of minor abnormality,

which implies repolarization abnormality and may not be

parallel to anatomical changes.

ICD has been proved to be the most effective treat-

ment of ARVC by far. During the follow-up, we ob-

served that the soldier und erwent anti-tachycardia pacing

(ATP) and shock therapy of ICD in the setting of VT,

which successfully terminated tachyarrhymia and pre-

vented it from degenerating in to ventricular fibrillation.

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