The Egyptian Journal of Critical Care Medicine (2013) 1, 95–104

The Egyptian College of Critical Care Physicians

The Egyptian Journal of Critical Care Medicine

http://ees.elsevier.com/ejccmwww.sciencedirect.com

ORIGINAL ARTICLE

Radiofrequency ablation of regular narrow complex

supraventricular tachycardia in elderly and pediatric

Wael Abd El-Latief b,*, Hassan Khaled a, Ahmed Abd ElAziz a, Gamal Shaban b

a Critical Care Medicine Department, Cairo University, Egyptb National Heart Institute, Egypt

Received 7 November 2012; revised 30 December 2012; accepted 6 January 2013Available online 5 February 2013

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KEYWORDS

Supraventricular tachycar-

dia;

Radiofrequency ablation

Corresponding author.

mail address: wael.elhakeem

Peer review under responsib

are Physicians.

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90-7303 � 2013 The Egyptia

pen access under CC BY-NC-ND li

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Abstract Background: Radiofrequency (RF) catheter ablation is a well established approach in

treating several types of cardiac arrhythmias whether supraventricular or ventricular and is in many

cases the first choice therapy. Radiofrequency ablation has been shown to be effective and safe with

a success rates ranging from 80% to 100%.

Furthermore, few studies had investigated the efficacy and safety of catheter ablation in elderly

patients and pediatrics patients.

Objectives: This study is prospective evaluation of the safety and efficacy of radiofrequency abla-

tion of regular narrow complex supraventricular tachycardia in both age extremes, elderly and

pediatric patients.

Methods: The study included 30 patients, 19 patients >60 years [group I] and 11 pediatric

patients <14 years [group II], referred to National Heart Institute and Critical Care Department

at Kasre AL-Ainy Cairo University hospital from October 2008 to October 2009 who underwent

electrophysiological study and radiofrequency catheter ablation to symptomatic supraventricular

tachyarrhythmia, medically refractory.

Results: Thirty patients had ablated presented with variable clinical characteristics in both

groups. The AVRT is more frequent in higher age group however the AVNRT is almost equally

distributed in both age group only two cases atrial flutter and atrial tachycardia. The success rate

in group I was 90% and in group II was 100%. No complications were recorded in group I and in

group II the only recorded complication was complete heart block in one patient that required per-

manent pacemaker insertion, also recurrence rate was zero in group two but two patients in group

one show recurrence at 6 months follow up.

com (W.A. El-Latief).

e Egyptian College of Critical

g by Elsevier

e of Critical Care Physicians. Production and hosting by Elsevier B.V.

://dx.doi.org/10.1016/j.ejccm.2013.01.003

96 W.A. El-Latief et al.

Conclusion: We have concluded that catheter ablation of supraventricular tachycardia is a very

good option for management of patients with drug resistant SVT in both young and old patients.

The success rate was very high almost with no complications and very low recurrence rate in the

elderly and no recurrence in the young during the 6 months follow-up.

� 2013 The Egyptian College of Critical Care Physicians. Production and hosting by Elsevier B.V.Open access under CC BY-NC-ND license.

Introduction

Paroxysmal supraventricular tachycardia incidence is approxi-

mately 1–3 cases per 1000 persons. The incidence rate of theWPW pattern on ECG tracings is 0.1–0.3% in the generalpopulation, although not all patients develop SVT [1]. In a

population-based study, the prevalence of paroxysmal supra-ventricular tachycardia was 2.25 cases per 1000 persons, withan incidence of 35 cases per 100,000 person-years [2]. AVNRTis more common in patients who are of middle age or older,

while adolescents are more likely to have SVT mediated byan accessory pathway. Paroxysmal supraventricular tachycar-dia is not only observed in healthy individuals, it is also com-

mon in patients with previous myocardial infarction, mitralvalve prolapse, rheumatic heart disease, pericarditis, pneumo-nia, chronic lung disease, and current alcohol intoxication.

Digoxin toxicity also may be associated with paroxysmalsupraventricular tachycardia [3].

Radiofrequency (RF) catheter ablation is a well establishedapproach in treating several types of cardiac arrhythmias

whether supraventricular or ventricular and is in many casesthe first choice therapy. Radiofrequency ablation has beenshown to be effective and safe with a success rates ranging

from 80% to 100% in patients with atrial flutter and exceeding90–95% in patients with atrioventricular nodal re-entranttachycardia (AVNRT) or atrioventricular re-entrant tachycar-

dia (AVRT) due to accessory pathways [4,5].The incidence of procedural complications ranges from

25% to 6% in different cases series [6–8].

Despite such encouraging data, the interventional approachin treating cardiac arrhythmia has not been widely adopted inelderly people, even though it may be particularly useful in thiskind of patient, in whom antiarrhythmic drugs are often

poorly tolerated [9].Indeed, the age related structural modification of the heart;

the higher prevalence of structural heart disease and the higher

thromboembolic risk are believed to increase of proceduralcomplications in the elderly patients in comparison with youngadults [10].

Furthermore, few studies had investigated the efficacy andsafety of catheter ablation in elderly patients and pediatricspatients [11,12].

Aim of this study

This study is prospective evaluation of the safety and efficacy

of radiofrequency ablation of regular narrow complex supra-

ventricular tachycardia in both age extremes, elderly and pedi-atric patients.

Study population

The study included 30 patients, 19 patients >60 years [group I]

and 11 pediatric patients <14 years [group II], referred to Na-tional Heart Institute and Critical Care Department at KasreAL-Ainy Cairo University hospital fromOctober 2008 to Octo-

ber 2009 who underwent electrophysiology study and radiofre-quency catheter ablation to variable indications. The inclusioncriteria were: life-threatening symptomatic supraventricular

tachyarrhythmia, medically refractory tachycardia, adversedrug effects, impending surgery, and the patient’s choice.

Methodology

Study protocol

All patients included in the study were subjected to the following

1. Full history taking with special emphasis on the history ofdysrrhythmias.

2. Full clinical examination.3. 12 – leads resting ECG.4. Twenty-four hour – dynamic ECG monitoring [Holter] to

document the presence of dysrrhythmias.5. Transthoracic echocardiography [TTE] for assessment of

the cardiac dimensions, evaluation of the presence of any

anatomical abnormalities and assessment of LV systolicand diastolic function.

6. Routine laboratory investigations including complete bloodpicture, liver and kidney function tests, lipid profile, thyroid

function tests and hepatitis markers.7. Radiofrequency catheter ablation:� Patients were brought to the electrophysiology labora-

tory in the post – absorptive state and always off anti-arrhythmic drugs for five half lifes.

� In all cases, 6 French quadpolar catheters were inserted

through right and left femoral veins and positioned inthe his bundle region and the right ventricular apex.

� A 6 French quadpolar catheter was then inserted thro-

ugh the left subclavian vein and positioned in the coro-nary sinus.

� In the atrial flutter ablation procedure, a 7 French Halocatheter was inserted through the left femoral vein and

positioned in the right atrium.

Figure 1 Cardiac co-morbid condition of the two groups, P

value = <0.05.

Figure 2 Non-cardiac co-morbid condition of the two groups, P

value = <0.05.

Radiofrequency ablation of regular narrow complexsupraventricular tachycardia in elderly and pediatric 97

� Detailed electrophysiological evaluation using standard

recording by general electric-PRUCA engineering andsimulation techniques by Micropace, EPS 320, cardiacstimulator (Cordis) was performed to confirm diagnosis

and to identify the target site for radiofrequency delivery.� Radiofrequency energy was applied through a 7-french

4-mm tip catheter in procedures for AVNRT, AVRTand AT and through a 7-french 8-mm tip catheter in

cases of atrial flutter.� The ablating catheter was inserted through the right f-

emoral vein in procedures for AVNRT, right accessory

pathways and AT.� The patients with left accessory pathways, the ablating

catheter was inserted through the right femoral artery,

atrial septal puncture and left atrial approach was usedin case of retrograde approach failure.

� Radiofrequency energy was applied by using an RF cur-rent generator for a time ranging from 30 to 120 s, with

a maximum tip temperature of 60–65 �C and a poweroutput of 50 W, ablator: ST 1642 – EP – Shuttle-Stoc-kert (Cordis).

Results

Clinical characteristics: group I had a significantly higher prev-alence of cardiovascular and non-cardiovascular comorbid

conditions (P < 0.05) Table 1, Figs. 1 and 2.Table 2 showed that the most commonly used drug therapy

was calcium channel blockers then beta blockers. The inci-

dence of the use of Cordarone, B-blockers and aspirin weresignificantly higher among group I than that of group II(P < 0.05).

The mean tachycardia duration were significantly higher in

group I than that of group II (P< 0.001).

Frequency of dysrrhythmia per year in the two groups

There was no significant different as regards frequency of dysr-rhythmia of both groups (Table 3) and (Fig. 3)

Table 4 show that the AVRT is more frequent in higher age

group; however the AVNRT is almost equally distributed inboth age group.

Table 1 Clinical characteristic of both groups.

Group I Group II P value

N % N %

Cardiac conditions

None 7 36.84 9 81.82 <0.05

Valvular 5 26.32 2 18.18

HTN 5 26.32 0 0.00

Other 2 10.53 0 0.00

Non cardiac conditions

None 12 63.16 9 81.8 <0.05

COPD 2 10.53 2 18.2

Dyslip 2 10.53 0 0.00

Diabetes 2 10.53 0 0.00

Epilepsy 1 5.26 0 0.00

Table 5 show that: slow pathway ablation was the only site

for AVNRT ablation in both groups but the left lateral acces-sory pathway was the target of ablation in most AVRT pa-tients in both groups, and only two patients in group 1 need

antiarrhythmics for non-specific atrial tachycardia afterablation.

Fluoroscopy time was more prolonged in group I and abla-tion duration was longer also in group I (with significant P

value): Table 6, Figs. 4 and 5.No complications recorded in group I and in group II apart

from complete heart block in 1 patient that required perma-

nent pacemaker insertion (Table 7).No recurrence rate recorded in group II at 1 or 6 months

follow- up period in group II while in group I the recurrence

occurred in 2 patients at 6 months follow up (10.53%) (Table8).

The following Figs. 6–8 show intracardiac tracing for pa-tients with AVRT and AVNRT during radiofrequency

ablation.

Discussion

Accessory pathway mediated tachycardias constitute 80% ofall the tachyarrhythmias during infancy. In some infants, sometachycardias they resolve as the child grows. Most SVTs

Table 5 Catheter ablation data of the 2 groups.

Group I Group II P value

N % N %

Ablation site

Focal AT (LASSO) 1 5.26 0 0.00 >0.05

Isthmus dependent A. Fl 1 5.26 0 0.00

LL Ap 6 31.58 4 36.36

Lps Ap 0 0.00 1 9.09

Rl Ap 1 5.26 0 0.00

Slow pathway 10 52.63 6 54.55

Access site

Right 12 63.16 7 63.64 >0.05

Left 1 5.26 2 18.18

Both 6 31.58 2 18.18

Catheter number

4 4 21.05 3 27.27 >0.05

5 15 78.95 8 72.73

Trans-septal 4 21.05 3 27.27 >0.05

Arterial 6 31.58 3 27.27 >0.05

Mode of initiation

Spontaneous 6 31.58 2 18.18 >0.05

Atrial pacing 10 52.63 4 36.36

Extra stimulus 3 15.79 5 45.45

Mode of termination

Spontaneous 3 15.79 3 27.27 >0.05

Overdrive 4 21.05 2 18.18

DC shock 7 36.84 1 9.09

Ablation 5 26.32 5 45.45

Post ablation test

Yes 19 100.00 11 100.00 NA

NO 0 0.00 0 0.00

Drug test

Yes 13 68.42 8 72.73 >0.05

NO 6 31.58 3 27.27

Post ablation antiarrhthmics

Yes 2 10.53 0 0.00 NA

NO 17 89.47 11 100.00

Table 2 Drug therapy before ablation in the two groups.

Group I N = 19 Group II N= 11 P value

N % N %

Cordarone 13 68.42 0 54.5 <0.05

B-blockers 11 57.9 8 72.7 <0.05

Ca-blockers 16 84.2 9 81.8 >0.05

ACE 10 52.6 0 0 NA

ARBs 4 21 0 0 NA

Statins 8 42.1 0 0 NA

Aspirin 19 100 6 54.5 <0.001

Anti-coagulant 3 15.8 0 0 NA

NA= not applicable.

Figure 3 Frequency of tachycardia per year in the two groups.

Table 4 Distribution of SVT in both groups.

Type of S.V.T Group I

(>60 years)

Group II

(<14 years)

AVNRT 10 (52.6%) 6 (54.5%)

AVRT 7 (36.8%) 5 (45.5%)

1. Left lateral AP 6 4

2. Right lateral AP 1 0

3. Left posteroseptal AP 0 1

A. Flutter 1 (5.3%) 0 (0%)

Atrial tachycardia 1 (5.3%) 0 (0%)

Table 3 Frequency of dysrrhythmia per year in the 2 groups.

Group I N= 19 Group II N= 11 P value

N % N %

More than 12 5 26.32 0 0.00 NA

Less than 12 14 73.68 11 100.00

Total 19 100.00 11 100.00 30

NA= not applicable.

98 W.A. El-Latief et al.

beyond the age of 5 tend to recur and may need to undergo RFablation. Ectopic atrial tachycardia and atrial flutter represent

10–15% of SVTs in infancy, of which some may not ever recur[13].

Radiofrequency ablation is uncommonly performed under5 years of age. This is because some SVTs resolve spontane-ously. Also, arrhythmias may get suppressed under the

Table 6 Cycle length, ablation duration and fluoroscopy time

in the 2 groups.

Group I N= 19 Group II N= 11 P value

Cycle length

(mean ± SD)

334.7 ± 32 338.1 ± 33.1 >0.05

Ablation duration

(mean ± SD) (sec.)

110.7 ± 21.3 87.5 ± 18.7 <0.01

Fluoroscopy time 41.8 ± 2.3 20.6 ± 1.8 <0.001

Table 7 Complications recorded during ablation in the 2

groups.

Group I N = 19 Group II N= 11

N % N %

Hematoma 0 0 0 0

Infection 0 0 0 0

Effusion 0 0 0 0

Embolization 0 0 0 0

Coronary thrombus 0 0 0 0

Complete heart block 0 0 1 9

Dissection 0 0 0 0

DVT 0 0 0 0

Death 0 0 0 0

Total 0 0 1 9

Figure 5 Fluoroscopy time in the two groups.

Figure 4 Ablation duration in the two groups.

Table 8 Recurrence rate at 1 and 6 months follow-up.

Group I N = 19 Group II N = 11

N % N %

1 month follow-up 0 0 0 0

6 months follow-up 2 10.53 0 0

Radiofrequency ablation of regular narrow complexsupraventricular tachycardia in elderly and pediatric 99

influence of anesthesia at the time of RF ablation. Patient size

poses limitations in using multiple electrode catheters andthere is an increased possibility of cardiac/valve damage withablation. The risks of ablation are acceptable only if the child

has recurrent, drug-resistant SVT especially if it results intachycardiomyopathy or life-threatening cardiovascular com-promise [14].

Cardiac arrhythmias are relatively uncommon in the youn-ger population, accounting for approximately 5% of all emer-gency cardiac admissions. Paroxysmal supraventricular

tachycardia (SVT) like atrio-ventricular reciprocating tachy-cardia (AVRT), ectopic atrial tachycardia, and atrio-ventricu-lar nodal reentrant tachycardia are the most common. In thosepatients who have undergone operations for congenital heart

disease, junctional ectopic tachycardia and atrial flutter aremore common. Symptoms of arrhythmias depend on theage, presence of structural heart disease, and the state of the

left ventricular function apart from the nature, severity, andduration of arrhythmia [15].

Atrioventricular nodal re-entry is the most common cause

of regular narrow complex SVT. In our study, 70% of SVTare due to atrioventricular nodal re-entry. If AVNRT are lessfrequent and responsive to therapy with beta blocker or cal-cium channel blocker, then RFA can be deferred [16].

Supraventricular tachycardias are the most frequent formsof symptomatic tachyarrhythmias in infants, children andadolescents. Clinical symptoms depend on age and underlying

cardiac anatomy. Newborn babies and infants with paroxys-mal atrioventricular reentrant tachycardias usually presentwith signs of congestive heart failure due to rapid heart rate

[17].Failure to discriminate among AF, atrial flutter, and other-

supraventricular arrhythmias has complicated the precise def-

inition of this arrhythmia in the general population. Theestimated prevalence of paroxysmal supraventricular tachycar-dia (PSVT) in a 3.5% sample of medical records in the Marsh-field (Wisconsin) Epidemiologic Study Area (MESA) was 2.25

per 1000. The incidence of PSVT in this survey was 35 per 100000 person-years [18].

In our study, we conducted a prospective clinical trial in the

National Heart Institute and critical care department at KasrAl-Ainy Cairo University hospital in order to evaluate thesafety and the efficacy of radiofrequency ablation in both

age extremes, elderly and pediatric patients.Our study included 30 patients; 19 patients >60 years of

age (group I) and 11 pediatric patients (group II).Group I included 19 patients, their age ranged between 61

and 71 years with a mean age of 67.5 ± 5.1 years, they were9 males (47.4%) and 10 females (52.6%) while in group II, theirmean age was 12.5 ± 3.5 years and they were 6 males (54.5%)

and 5 females (45.6%). There was no significant difference be-

Figure 6 Intracardiac tracing showing surface L1and V2 (preexcited) and shortest AV in PCS (in sinus rhythm) denoting the presence of

antegrade conduction via Lt posteroseptal AP. RF ablation was applied via the ablation catheter which recorded shortest AV than that of

PCS catheter.

100 W.A. El-Latief et al.

tween the 2 groups regarding their sex distribution (P > 0.05).The heart rate was significantly higher among group II thanthat of group I but the systolic and diastolic blood pressure

was significantly higher among group II than that of group I(P < 0.05).

Results of the current study showed that group I had a sig-

nificantly higher prevalence of cardiovascular and non-cardio-vascular comorbid conditions (P < 0.05).

Results of the current study showed the most commonly

used drug therapy was calcium channel blockers then betablockers. The incidence of the use of Cordarone, B-blockersand aspirin were significantly higher among group I than thatof group II (P < 0.05).

Results of the current study showed the mean tachycardiaduration were significantly higher than in group I than thatof group II (P < 0.001).

Results of our study showed that no complications re-corded in group I and in group II the only recorded complica-

tion was complete heart block in 1 patient that requiredpermanent pacemaker insertion.

In our study there was no recurrence rate recorded in group

II at 1 and 6 months follow up in group II, while in group I therecurrence occurred in 2 patients at 6 months follow up(10.53%).

However in patients with frequent episodes or hemody-namic intolerance or those who refuse prolonged medication,RFA is a safe and cost effective treatment modality. The suc-

cess rate is more than 96% and the risk of damaging thecompact AV node is <1% and the recurrence rate is also<3% [19]. But in our study may be explained by small numberof patients and the recurrence rate in AVNRT has been very

low because it had been part of our protocol to look for slowjunctional rhythm during RFA and to insure with isoprotero-nol the tachycardia could no longer be reinduced once RFA

had been done. The presence of a junctional rhythm duringslow-pathway ablation has been indisputably considered to

Figure 7 During RF ablation, slow junctional rhythm denoting potential successful ablation in patient with AVNRT from group I.

Radiofrequency ablation of regular narrow complexsupraventricular tachycardia in elderly and pediatric 101

be the most sensitive but non-specific marker of successful

ablation.In our study we found that RF ablation was safe in children

with a very high success rate and very low complication rateand these results are not in agreement with Hsieh et al. [20]

who stated that children were not considered for radiofre-quency ablation because is not very safe in this age andcryo-ablation is a preferable option for AVNRT.

Our results are different from the study of Shuenn-Nan etal. [21] who studied 27 patients (17 males, 10 females) under-went RFA at an age less than 6 years. All of his patients had

drug-refractory SVT or tachycardia-induced cardiomyopathy.They found that immediate success rate was 92.6%, with lowearly (3.7%) and late recurrence (7.4%) after 5.4 ± 3.7 yearsfollow-up. Tachycardia-induced cardiomyopathy was noted

in 4 and resolved in all after RFA. Procedure-related compli-

cations included complete atrioventricular block in 1. No otherrisk factors for outcomes were noted, even with low bodyweight. He concluded that the outcome of RFA for medicallyrefractory SVT, even associated with tachycardia-induced car-

diomyopathy, in infants is favorable [21]. The higher recur-rence rate and lower success rate in their study may bebecause they included younger patients and longer follow up

period.Results of our study showed that RF ablation of young

children was a good and safe way of management of patients

with SVT and these results agreed with that reported by VanHare, [22] who stated that long-term management of AVRTin infancy and childhood is age dependent. In newborn babiesand infants, pharmacological therapy is advised due to the

Figure 8 Normalization during RF application as evidenced by the QRS complex is no more preexisted and prolongation of AV interval

in pt with Lt posterolateral AP (target site of ablation at MCS).

102 W.A. El-Latief et al.

high spontaneous cessation rate of those tachycardias at the

end of the first year of life. In contrast to this, the probabilityof spontaneous cessation of tachycardia in children >1 year ofage is very low. Therefore, radiofrequency catheter ablation ofthe anatomical substrate of the tachycardia is a rational

alternative to long-lasting antiarrhythmic therapy.Our results are also in agreement with the study of Aiyagari

et al. 2005 [23] who found that RFA in children with a struc-

turally normal heart are comparable to those achieved inadults.

Paul et al. [17] supported our conclusion in that pharmaco-

logical therapy is often not sufficient to control the tachycar-dia. In addition, underlying sinus node dysfunction may beaggravated in a considerable portion of the patients affected.

Also Baine et el. [24] supported our conclusion as supraven-tricular arrhythmias are relatively common, often repetitive,occasionally persistent, and rarely life threatening. The precip-itants of supraventricular arrhythmias vary with age, sex, and

associated comorbidity [24].

Age exerts an influence on the occurrence of SVT. The

mean agent the time of PSVT onset in the MESA (Multi Eth-nic Study of Atherosclerosis) cohort was 57 years (rangingfrom infancy to more than 90 years old) [2]. In the MESApopulation, compared with those with other cardiovascular

disease, ‘‘lone’’ (no cardiac structural disease) PSVT patientswere younger (mean age equals 37 versus 69 years), had fasterheart rates (186 versus 155 beats per minute [bpm]), and were

more likely to present first to an emergency room (69% versus30%). The age of tachycardia onset is higher for AVNRT (32plus or minus 18 years) than for AVRT (23 plus or minus

14 years) [2].Gender plays a role in the epidemiology of SVT. Female

residents in the MESA population had a two-fold greater rel-

ative risk (RR) of PSVT (RR equals 2.0; 95% confidence inter-val equals 1.0–4.2) compared with males [2].

In our study we targeted the slow pathway along the pos-terolateral region of the tricuspid annulus which yielded a high

success rate and a low complication rate (only one patient hadcomplete heart block, and our results are in agreement with

Radiofrequency ablation of regular narrow complexsupraventricular tachycardia in elderly and pediatric 103

that reported by Fuster et al. [18] who mentioned that target-ing the slow pathway along the posteroseptal region of the tri-cuspid annulus markedly reduces the risk of heart block and is

the preferable approach. Advantages of slow-pathway abla-tion include a lower incidence of complete AV block (1% ver-sus 8%) and the absence of the hemodynamic consequences of

marked prolongation of the PR interval. Hence, slow pathwayablation is always used initially and fast pathway ablation isconsidered only when slow pathway ablation fails.

Our results are also in agreement with the NASPE prospec-tive catheter ablation registry which included 1197 patientswho underwent AV-nodal modification for AVNRT. Successwas achieved in 96.1%, and the only significant complication

was a 1% incidence of second-degree or third-degree AV block[25]. These data have been confirmed by Clague et al. [26].Atrioventricular block may complicate slow-pathway ablation

caused by posterior displacement of the fast pathway, superiordisplacement of the slow pathway (and coronary sinus), orinadvertent anterior displacement of the catheter during RF

application. Pre-existing first-degree AV block does not appearto increase appreciably the risk of developing complete AVblock, although caution is advised. The recurrence rate after

ablation is approximately 3–7% [27].Ablation of the slow pathway may be performed in patients

with documented SVT (which is morphologically consistentwith AVNRT) but in whom only dual AV-nodal physiology

(but not tachycardia) is demonstrated during electrophysiolog-ical study [18].

Slow-pathway ablation may be considered at the discretion

of the physician when sustained (more than 30 s) AVNRT isinduced incidentally during an ablation procedure directed ata different clinical tachycardia [18].

Indications for ablation depend on clinical judgment andpatient preference. Factors that contribute to the therapeuticdecision include the frequency and duration of tachycardia,

tolerance of symptoms, effectiveness and tolerance of antiar-rhythmic drugs, the need for lifelong drug therapy, and thepresence of concomitant structural heart disease. Catheterablation has become the preferred therapy, over long-term

pharmacologic therapy, for management of patients withAVNRT. The decision to ablate or proceed with drug therapyas initial therapy is, however, often patient specific, related to

lifestyle issues (e.g., planned pregnancy, competitive athlete,recreational pilot), affected by individual inclinations or aver-sions with regard to an invasive procedure or the chronicity of

drug therapy, and influenced by the availability of an experi-enced center for ablation. Because drug efficacy is in the rangeof 30–50%, catheter ablation may be offered as first-linetherapy for patients with frequent episodes of tachycardia.

Patients considering RF ablation must be willing to acceptthe risk of AV block and pacemaker implantation [18].

Catheter ablation of accessory pathways is performed in

conjunction with a diagnostic electrophysiological test. Thepurposes of the electrophysiological test are to confirm thepresence of an accessory pathway, determine its conduction

characteristics, and define its role in the patient’s clinicalarrhythmia. Once the arrhythmia is identified, ablation is per-formed using a steerable ablation catheter. There have been no

prospective, randomized clinical trials that have evaluated thesafety and efficacy of catheter ablation of accessory pathwaysversus pharmacological treatment, however, the results ofcatheter ablation of accessory pathways have been reported

in a large number of single-center trials, one multicenter trial[27] and several prospective registries [25]. The initial efficacyof catheter ablation of accessory pathways is approximately

95% in most series [27]. The success rate for catheter ablationof left free-wall accessory pathways is slightly higher than forcatheter ablation of accessory pathways in other locations.

After an initially successful procedure, resolution of theinflammation or edema associated with the initial injury allowsrecurrence of accessory pathway conduction in approximately

5% of patients. Accessory pathways that recur can usually besuccessfully ablated during a second session [18].

Complications associated with catheter ablation of acces-sory pathways result from radiation exposure, vascular access

(e.g., hematomas, deep venous thrombosis, arterial perfora-tion, arteriovenous fistula, pneumothorax), catheter manipula-tion (e.g., valvular damage, microemboli, perforation of the

coronary sinus or myocardial wall, coronary artery dissection,thrombosis), or delivery of RF energy (e.g., AV block, myocar-dial perforation, coronary artery spasm or occlusion, transient

ischemic attacks, or cerebrovascular accidents). The proce-dure-related mortality reported for catheter ablation of acces-sory pathways ranges from 0% to 0.2% [25]. The voluntary

Multicenter European Radiofrequency Survey (MERFS)reported data from 2222 patients who underwent catheterablation of an accessory pathway. The overall complicationrate was 4.4%, including 3 deaths (0.13%). The 1995 NASPE

survey of 5427 patients who underwent catheter ablations ofan accessory pathway reported a total of 99 (1.82%) significantcomplications, including 4 procedure-related deaths (0.08%).

Among the 500 patients who underwent catheter ablation ofan accessory pathway as part of a prospective, multicenterclinical trial, there was 1 death (0.2%). This patient died of dis-

section of the left main coronary artery during an attempt atcatheter ablation of a left free-wall accessory pathway [25].

The most common major complications are complete AV

block and cardiac tamponade. The incidence of in advertentcomplete AV block ranges from 0.17% to 1.0%. Most occurin the setting of attempted ablation of septal accessory path-ways located close to the AV junction. The frequency of car-

diac tamponade varies between 0.13% and 1.1%.The higher incidence of complications in the previously

mentioned study could be explained by that, they included a

larger number of patients and at longer duration of the studyas well as the bigger number of operators.

Conclusion

Catheter ablation of supraventricular tachycardia is a very

good option for management of patients with drug resistant

SVT in both young and old patients.The success rate was very high almost with no complica-

tions and very low recurrence rate in the elderly and no recur-rence in the young during the 6 months follow-up.

Older patients had more comorbid conditions with longerduration of ablation and higher energy frequency as well asmore fluoroscopic time.

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