Arrhythmia 2015;16(1):59-64
ECG & EP CASES
Accessory Pathway with Decremental
Conduction Properties
Yong Seog Oh, MD, PhD
Division of Cardiology, Depeartment of Internal Medicine,
Catholic University of Korea
Received: December 25, 2014
Revision Received: February 18, 2015
Accepted: March 26, 2015
Correspondence: Yong-Seog Oh, MD, PhD,
Director of Electrophysiology, Division of
Cardiovascular Medicine, Seoul St. Mary's
Hospital, The Catholic University of Korea,
College of Medicine, 505 Banpo-Dong, SeochoKu, Seoul, 137-040, Republic of Korea
Tel: +82-2-2258-6031, Fax: +82-2-592-3810
E-mail: oys@catholic.ac.kr
ABSTRACT
Permanent junctional reciprocating tachycardia (PJRT) is an orthodromic atrioventricular tachycardia mediated by a concealed accessory pathway with slow conduction and decremental property. The
accessory pathway in PJRT is most often located in the posteroseptal
region, especially around the coronary sinus ostium. Here I describe
a case of clinical tachycardia with a long RP interval due to slow
retrograde conduction.
Key Words: supraventricular tachycardia, accessory pathway
Copyright © 2015 The Official Journal of Korean Heart
Rhythm Society Editorial Board & MMK Co., Ltd.
Introduction
echocardiography, with an ejection fraction of 62%. Twenty-fourhour Holter monitoring showed repeated induction of
Narrow-QRS tachycardia with a long RP interval presents interesting
supraventricular tachycardia (SVT), with intervening periods of
diagnostic challenges. A correct diagnosis is essential for performing safe
sinus rhythm lasting a few minutes. I administered IV adenosine,
and effective catheter ablation. The differential diagnosis of
verapamil injection, and DC cardioversion several times in an
narrow-QRS tachycardia with a long RP interval includes atypical
attempt to terminate the tachycardia, but after few seconds in
atrioventricular nodal reentrant tachycardia (AVNRT), ectopic
sinus rhythm the tachycardia was reinduced and sustained. To
atrial tachycardia, and atrioventricular reentrant tachycardia (AVRT)
maintain sinus rhythm I prescribed 240 mg of verapamil or 150
with a decremental property. I present a case of permanent junctional
mg of atenolol per os; however, the patient continued to exhibit
reciprocating tachycardia (PJRT) with a long RP interval that exhibited a
the same drug-refractory tachycardia.
decremental property.
The patient was scheduled for electrophysiological study and
catheter ablation. In the electrophysiology lab she showed SVT
Case
with intermittent short periods of sinus rhythm. The SVT could
be easily induced by one premature ventricular contraction
A 65-year-old woman was referred to our hospital for sustained
(PVC), and was also inducible in sinus rhythm without any AH
palpitations and general weakness. The electrocardiogram (ECG)
jump (Figure 2). For the differential diagnosis, I applied a PVC
showed narrow QRS tachycardia of ~120 /min, with an inverted
during SVT. In contrast to orthodromic AVRT without a
P wave in leads II, III, aVF, and a long RP interval in all precordial
decremental property, after the PVC the AA interval was
leads (Figure 1). She had normal left ventricular function on
prolonged from 467 ms to 494 ms (Figure 3). To ablate the
59
Arrhythmia 2015;16(1):59-64
A
B
Figure 1. (A) Electrocardiogram in tachycardia, (B) Electrocardiogram in sinus rhythm.
accessory pathway, I identified the earliest activation site of A in
diagnosis was the atrial response to a PVC during the His
the right posteroseptal area (Figure 4, Figure 5). After 4 seconds of
refractory period. Since the atrial activation was delayed by the
radiofrequency application, the SVT terminated and showed
PVC, AVNRT could be excluded.1
ventriculoatrial dissociation (Figure 6). The patient remained in
PJRT is an orthodromic AVRT mediated by a concealed and
hospital for two days after the catheter ablation and was
slow-conducting accessory pathway. The clinical course of PJRT is
discharged in sinus rhythm.
not always benign. Many patients try multiple antiarrhythmic
drugs and ultimately require catheter ablation. Radiofrequency
Discussion
catheter ablation is a safe and effective therapy.2 However, the
higher recurrence rate of PJRT, compared with that of reentry
In this case, no preexcitation was observed. During the
with no decremental property, may be explained by the long,
tachycardia, the earliest atrial activation was observed around the
tortuous course of the accessory pathway. The most important
coronary sinus ostium. The critical finding for the differential
complication of incessant PJRT is tachycardia-induced
60
Accessory Pathway with Decremental Conduction Properties
A
B
Figure 2. (A) Electrocardiogram showing induction of supraventricular tachycardia (SVT) by a premature ventricular contraction (PVC), (B) Electrogram showing SVT induction by PVC.
61
Arrhythmia 2015;16(1):59-64
A
B
Figure 3. (A) Electrocardiogram showing induction of supraventricular tachycardia (SVT) in sinus rhythm, (B) Electrogram
showing SVT induction in sinus rhythm.
62
Accessory Pathway with Decremental Conduction Properties
Figure 4. The earliest atrial activation site in supraventricular tachycardia.
RAO
LAO
Figure 5. Catheter in fluoroscopic view.
RAO, right anterior oblique projection; LAO, left anterior oblique projection.
63
Arrhythmia 2015;16(1):59-64
A
B
Figure 6. (A) Electrogram showing termination of supraventricular tachycardia, (B) Electrogram showing ventriculoatrial
dissociation.
cardiomyopathy, which has been observed in 18% of patients with
2) Meiltz A, Weber R, Halimi F, Defaye P, Boveda S, Tavernier R,
PJRT. Slower conduction through the accessory pathway has a
Kalusche D, Zimmermann M. Permanent form of junctional
wider excitable gap. In most cases of PJRT, the accessory pathway
reciprocating tachycardia in adults: peculiar features and results of
is located in the posteroseptal region.
radiofrequency catheter ablation. Europace. 2006;8:21-28.
3
3) Bensler JM, Frank CM, Razavi M, Rasekh A, Saeed M, Haas PC,
References
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Electrophysiological features differentiating the atypical
atrioventricular node- dependent long RP supraventricular
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Nazeri A, Massumi A. Tachycardia-mediated cardiomyopathy and
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