Radiofrequency catheler ablation of atrioventricular nodal reentry tachycardia: Selective approach to the slow pathway via the superior vena cava

Abstract

Selective radiofrequency catheter ablation of the slow atrioventricular nodal pathway is currently considered the first-line therapy for patients suffering from recurrent symptomatic atrioventricular nodal reentry tachycardia. In most cases slow pathway conduction may be selectively eliminated or modified by the application of radiofrequency current at the posterior portion of Koch's triangle. The ablation site is usually targeted by careful mapping of this area performed using an ablation catheter advanced via the inferior vena cava approach. In this report we describe 2 cases in which the conventional approach to the target site was either impossible owing to the presence of an atresic inferior vena cava (case 1), or contraindicated in view of a history of common femoral vein thrombosis, subsequently extended up to the inferior vena cava (case 2). In both patients a superior vena cava approach was utilized and the slow pathway was successfully ablated. In case of arrhythmias necessitating slow pathway mapping and ablation, such an approach may be considered as a feasible and safe alternative whenever, owing to the presence of anomalies and/or diseases of the inferior vena cava, the conventional approach cannot be employed.

Full text

142
Introduction
Radiofrequency catheter modification
or elimination of the slow atrioventricular
nodal pathway is currently considered the
first-line treatment for patients presenting
with recurrent symptomatic atrioventricular
nodal reentry tachycardia (AVNRT)1. The
slow pathway is commonly localized at the
posterior portion of Koch’s triangle2. The ef-
fective ablation site is generally targeted
by careful mapping of this area, accom-
plished using a deflectable catheter ad-
vanced along the inferior vena cava (IVC).
In this report, we describe 2 cases in which
a superior vena cava (SVC) approach was
utilized to successfully ablate the slow path-
way in 2 patients in whom the convention-
al approach to the target site was either im-
possible or contraindicated owing to con-
genital (case 1) and acquired (case 2) disease
of the IVC.
Description of cases
Case 1. A 44-year-old woman was admit-
ted to our hospital for recurrent episodes of
paroxysmal palpitation. A 12-lead ECG,
recorded during an arrhythmic episode,
showed a narrow QRS complex supraven-
tricular tachycardia at a rate of 180 b/min.
P waves were discernible and the RP’ in-
terval was much shorter than the P’R in-
terval. Vagal maneuvers as well as intra-
venous antiarrhythmic drugs administered
in the emergency room had successfully
terminated the arrhythmic attacks, whereas
chronic oral antiarrhythmic therapy was in-
effective in preventing recurrences. The pa-
tient’s past medical history included pleurisy
and appendicectomy at 22 and 36 years of
age respectively. On admission, physical
examination as well as chest X-ray and
transthoracic echocardiography were nor-
mal. A12-lead ECG recorded during sinus
rhythm excluded manifest ventricular pre-
excitation or any other abnormality. Having
© 2001 CEPI Srl
Received October 27,
2000; accepted November
23, 2000.
Address:
Prof. Jorge A. Salerno-Uriarte
Università degli Studi
dell’Insubria-Varese
Dipartimento di
Cardiologia “Mater Domini”
Via Gerenzano, 2
21053 Castellanza (VA)
E-mail: jsalerno@unipv.it
Case reports
Radiofrequency catheter ablation
of atrioventricular nodal reentry tachycardia:
selective approach to the slow pathway
via the superior vena cava
Andrea Avella, Roberto De Ponti, Massimo Tritto, Giammario Spadacini,
Jorge A. Salerno-Uriarte
Department of Cardiology “Mater Domini”, Castellanza (VA), University of Insubria-Varese, Italy
Selective radiofrequency catheter ablation of the slow atrioventricular nodal pathway is current-
ly considered the first-line therapy for patients suffering from recurrent symptomatic atrioventricu-
lar nodal reentry tachycardia. In most cases slow pathway conduction may be selectively eliminated
or modified by the application of radiofrequency current at the posterior portion of Koch’s triangle.
The ablation site is usually targeted by careful mapping of this area performed using an ablation catheter
advanced via the inferior vena cava approach. In this report we describe 2 cases in which the conventional
approach to the target site was either impossible owing to the presence of an atresic inferior vena ca-
va (case 1), or contraindicated in view of a history of common femoral vein thrombosis, subsequent-
ly extended up to the inferior vena cava (case 2). In both patients a superior vena cava approach was
utilized and the slow pathway was successfully ablated. In case of arrhythmias necessitating slow path-
way mapping and ablation, such an approach may be considered as a feasible and safe alternative when-
ever, owing to the presence of anomalies and/or diseases of the inferior vena cava, the conventional ap-
proach cannot be employed.
(Ital Heart J 2001; 2 (2): 142-146)
Key words:
Superior vena cava;
Supraventricular
tachycardia;
Transcatheter
ablation.

A Avella et al - Superior vena cava approach to slow pathway
obtained written informed consent from the patient, an
off-drug electrophysiologic study was performed in a
fasting nonsedated state. Following local anesthesia
(0.5% bupivacaine), a 6F tetrapolar catheter (Soloist,
Medtronic Puerto Rico, Villalba, PR, USA) was inserted
into the right common femoral vein. While maneu-
vering the catheter under fluoroscopic guidance, the op-
erator failed to advance it directly into the right atrium,
the catheter course resulting posterior to the cardiac sil-
houette, as observed at the left lateral fluoroscopic
view. Further advancement of the catheter permitted
passage beyond the cardiac silhouette and into the
right atrium via the SVC. Subsequently, contrast medi-
um injection into the right and left iliac veins revealed
that the IVC was not present. Passage of the catheter
via a large azygos vein, into the SVC and then into the
right atrium was confirmed. Subsequently, by means of
a long 0.032 inch guide wire, similarly advanced
through the SVC, the inferior part of the right atrium
was probed. No access to the IVC could be found. In
view of this evidence, consistent with infrahepatic
atresia of the IVC, a second 6F tetrapolar catheter
(Soloist, Medtronic) and a 7F bidirectional, deflec-
table mapping/ablation catheter (Stinger F Curve, Bard
Electrophysiology, Lowel, MA, USA) were positioned
in the coronary sinus and at the apex of Koch’s trian-
gle from the right basilic and the left subclavian veins
respectively (Fig. 1A). The ablation catheter deflec-
tability allowed stable recording of the His bundle
electrogram (Fig. 1B).
Baseline electrophysiologic study revealed dual
atrioventricular nodal physiology but excluded the pres-
ence of accessory atrioventricular connections. By pro-
grammed atrial stimulation, a typical AVNRT, with a cy-
cle length of 350 ms, resulted reproducibly inducible
when the antegrade fast pathway effective refractory pe-
riod was reached. Then, by deflecting the ablation
catheter in the opposite direction, the distal electrode was
moved from the His bundle area to the posterior aspect
of Koch’s triangle, where mapping was carefully per-
formed in sinus rhythm. A possible slow pathway po-
tential was located slightly anterior to the coronary si-
nus ostium (Fig. 2). By applying a moderate counter-
clockwise rotation on the ablation catheter, stable con-
tact was achieved. Asingle radiofrequency energy ap-
plication delivered at this site for 30 s, in the tempera-
ture control mode (target temperature 65°C), resulted in
the early occurrence of an accelerated junctional rhythm
(Fig. 3). Subsequently, programmed and incremental atri-
al stimulation showed a continuous atrioventricular
nodal antegrade conduction curve and the absence of any
reentrant arrhythmia, even during isoproterenol infusion.
Ventricular stimulation did not reveal any modification
of the retrograde Wenckebach point. No arrhythmias
were induced. During the follow-up period of 8 months
no arrhythmias recurred, confirming the success of the
procedure.
Case 2. A 74-year-old woman was referred to our hos-
pital because of weekly episodes of sustained sympto-
matic AVNRT, unresponsive to various antiarrhythmic
drugs. Patient history included essential hypertension
lasting 10 years and a hemorrhagic stroke resulting in
143
Figure 1. Panel A: right anterior oblique fluoroscopic view (30°RAO) showing the electrode catheters positioned within the coronary sinus and the mid-
right atrium, from the right subclavian and the azygos veins respectively. The mapping/ablation catheter is positioned in the His bundle region from the
left subclavian vein. AzV = azygos vein; Csos = coronary sinus ostium; HB = His bundle region; LSV = left subclavian vein; RA = right atrium; RSV
= right subclavian vein; SVC = superior vena cava. Panel B: surface ECG leads I, II and III simultaneously recorded with bipolar intracardiac elec-
trograms from the distal and proximal coronary sinus, the right atrium and the His bundle region during sinus rhythm. CSd = distal coronary sinus; CSp
= proximal coronary sinus; HBE = His bundle electrogram; RA = right atrium.
AB

Ital Heart J Vol 2 February 2001
aphasia and right hemiparesis at 72 years of age. Six
months before admission to our hospital, she had un-
dergone an unsuccessful catheter ablation of the slow
atrioventricular nodal pathway at another institution,
complicated by right common femoral vein thrombosis
subsequently extended up to the IVC.
On admission, physical examination did not disclose
any signs of congestive heart failure. A12-lead ECG,
recorded in sinus rhythm, revealed only T wave aspe-
cific abnormalities in the right precordial leads. Chest
X-ray and transthoracic echocardiography were normal.
Owing to the recent thrombotic vasculopathy, it was de-
cided to employ a SVC approach in order to perform
electrophysiologic evaluation. Having obtained written
informed consent from the patient and administered lo-
cal anesthesia (0.5% bupivacaine), a 6F decapolar
catheter (Response, Daig Corporation, Minnetonka,
MN, USA) was inserted into the right basilic vein
and then positioned within the coronary sinus. A 7F
bidirectional deflectable mapping/ablation catheter
(Stinger F Curve, Bard Electrophysiology) was in-
serted into the left subclavian vein and then posi-
tioned across the tricuspid valve. The His bundle elec-
trogram was recorded. Baseline electrophysiologic
evaluation, performed in a fasting nonsedated state,
confirmed dual atrioventricular nodal physiology and
excluded the presence of accessory atrioventricular
pathways. Programmed atrial stimuli, applied at the
mid-coronary sinus, documented the reproducible in-
ducibility of a typical AVNRT, with a cycle length of
390 ms. Then, by deflecting the ablation catheter from
the His position downwards and posteriorly, the pos-
terior aspect of Koch’s triangle was mapped in detail
during sinus rhythm. Apossible slow pathway poten-
tial was localized along the tricuspid annulus imme-
diately anterior to the coronary sinus ostium (Fig. 4).
Whilst maintaining stable contact by applying a coun-
terclockwise torque on the ablation catheter, ra-
diofrequency current in the temperature control mode
(target temperature 65°C) was delivered at this site for
45 s. An active junctional rhythm rapidly ensued. Sub-
sequent electrophysiologic evaluation confirmed suc-
cessful ablation of the slow pathway and demonstrat-
ed the impossibility of inducing any reentrant ar-
rhythmia, even during isoproterenol infusion. No ar-
rhythmia recurrences occurred during the follow-up pe-
riod lasting 3 months.
144
Figure 2. Panel A: right anterior oblique fluoroscopic view (30°RAO) showing the right atrium catheter in a higher position and the bidirectional map-
ping/ablation catheter deflected in the posterior portion of Koch’s triangle, where a slow pathway potential is recorded. Abl = slow pathway ablation
site. Panel B: bipolar intracardiac recording, at the target ablation site, showing a slow pathway potential (arrow). Abl = target site electrogram. Oth-
er abbreviations as in figure 1.
Figure 3. An accelerated junctional rhythm occurring 5 s after the on-
set (arrow) of radiofrequency application at the target site. RF on = on-
set of radiofrequency application. Other abbreviations as in figures 1 and
2.
AB

A Avella et al - Superior vena cava approach to slow pathway
Discussion
Selective radiofrequency catheter ablation of the
slow atrioventricular nodal pathway is currently con-
sidered the first-line therapy for all forms of AVNRT3.
In the majority of patients, slow pathway conduction may
be selectively eliminated by applying radiofrequency cur-
rent at the posterior portion of Koch’s triangle2. The dif-
ferent techniques4-7 used to target the effective ablation
site (anatomically guided, electrogram guided and com-
bined techniques) are exclusively performed following
right atrium catheterization achieved via the IVC ap-
proach. In fact this approach is believed to allow for bet-
ter stability of the ablation catheter.
In this report we describe 2 cases in which the con-
ventional approach was either impossible or con-
traindicated, because of the presence of congenital
anomalies (case 1) and acquired diseases (case 2) of the
IVC. The first patient presented with atresia of the IVC,
a rare but generally asymptomatic malformation re-
sulting from failure of the right subcardinal vein branch-
es to join the veins of the primitive liver. In this anom-
aly the postrenal segment of the IVC joins the azygos-
hemiazygos veins and drains into the SVC, whereas
the hepatic veins drain directly into the right atrium8. The
second patient presented with a recent history of throm-
bosis of the IVC, as a late complication of a previous
unsuccessful attempt at slow pathway ablation per-
formed at another institution. In both patients a SVC ap-
proach was utilized to ablate the slow pathway. The use
of a bidirectional deflectable ablation catheter allowed
accurate mapping and stable positioning in both the an-
terior and posterior areas of Koch’s triangle. Thus the
atrioventricular node and His bundle were correctly
localized and precise ablation of the slow atrioventric-
ular nodal pathway was possible. The SVC approach is
commonly employed to ablate the right anteroseptal and
anterior accessory pathways when the IVC approach
does not permit satisfactory catheter stability9,10. Fur-
thermore, this approach has already been employed in
a patient with congenital absence of the IVC11, in whom
a right posteroseptal accessory pathway was success-
fully ablated. Finally, the SVC approach for slow path-
way ablation adopted in these two cases can also be used
in every patient, in whom an IVC filter has been im-
planted for recurrent thromboembolism.
In conclusion, although the transvenous femoral
approach may allow for easier catheter positioning
within the Koch’s triangle and for better stability at the
target site, the SVC route should be considered as a fea-
sible and safe alternative for patients who present with
congenital anomalies and/or acquired diseases of the IVC
and who necessitate mapping and ablation of the slow
pathway.
References
01. ACC/AHA Task Force Report. Guidelines for clinical in-
tracardiac electrophysiological and catheter ablation proce-
dures. J Am Coll Cardiol 1995; 26: 555-73.
02. Haissaguerre M, Jais P, Shah D, et al. Analysis of electro-
physiological activity in Koch’s triangle relevant to ablation
of the slow AV nodal pathway. Pacing Clin Electrophysiol
1997; 20 (Part I): 2470-81.
03. Otomo K, Wang Z, Lazzara R, Jackman WM. Atrioventric-
ular nodal reentrant tachycardia: electrophysiological char-
acteristics of four forms and implication for the reentrant cir-
145
Figure 4. Panel A: right anterior oblique fluoroscopic view (30°RAO) showing the decapolar catheter positioned within the coronary sinus and the bidi-
rectional mapping/ablation catheter deflected in the posterior portion of Koch’s triangle. Abl = slow pathway ablation site; IVC = inferior vena cava.
Panel B: surface ECG leads I, II, III, V1and V5simultaneously recorded with bipolar intracardiac electrograms from the decapolar coronary sinus catheter
and the mapping/ablation catheter, during sinus rhythm. CS1 to CS5 indicates distal to proximal coronary sinus electrode pairs. Abl = target site elec-
trogram showing slow pathway potential (arrow). Other abbreviations as in figure 1.
AB

Ital Heart J Vol 2 February 2001
cuit. In: Zipes DP, Jalife J, eds. Cardiac electrophysiology:
from cell to bedside. 3rd edition. Philadelphia, PA: WB
Saunders, 2000: 504-21.
04. Jackman WM, Beckman KJ, McClelland JH, et al. Treatment
of supraventricular tachycardia due to atrioventricular nodal
reentry by radiofrequency catheter ablation of slow path-
way conduction. N Engl J Med 1992; 327: 313-8.
05. Jazayeri MR, Hempe SL, Sra JS, et al. Selective transcatheter
ablation of the fast and slow pathways using radiofrequen-
cy energy in patients with atrioventricular nodal reentrant
tachycardia. Circulation 1992; 85: 1318-28.
06. Haissaguerre M, Gaita F, Fischer B, et al. Elimination of atrio-
ventricular nodal reentrant tachycardia using discrete slow po-
tentials to guide application of radiofrequency energy. Cir-
culation 1992; 85: 2162-75.
07. Willems S, Shenasa H, Kottkamp H, et al. Temperature-con-
trolled slow pathway ablation for treatment of atrioventric-
ular nodal reentrant tachycardia using a combined anatomi-
cal and electrogram guided strategy. Eur Heart J 1996; 17:
1092-102.
08. Mayo J, Gray R, St Louis E, Grosman H, McLoughlin M,
Wise D. Anomalies of the inferior vena cava. AJR Am J
Roentgenol 1983; 140: 339-45.
09. Schluter M, Kuch H. Catheter ablation from right atrium of
anteroseptal accessory pathways using radiofrequency cur-
rent. J Am Coll Cardiol 1992; 19: 663-70.
10. Zhu DWX. Radiofrequency catheter ablative therapy for an-
teroseptal and midseptal accessory atrioventricular path-
ways. In: Singer I, ed. Interventional electrophysiology. Bal-
timore, MD: Williams & Wilkins, 1997: 253-73.
11. Inama G, Vergara G, Gramegna L, Rillo M, Fuochi C,
Furlanello F. Catheter ablation of Wolff-Parkinson-White
syndrome associated with congenital absence of inferior ve-
na cava. J Interv Card Electrophysiol 1998; 2: 301-4.
146