Impact of catheter surgical ablation on arrhythmia in ... · requisite for surgical ablation or implantation ofanantitachycardia pacemaker. Therapeuticoptions havebeenextendedby the

Br Heart J 1992;67:99-105

PRACTICE REVIEWED

Impact of catheter and surgical ablation onarrhythmia treatment in a tertiary referral centre

David Cunningham, Edward Rowland

AbstractInvasive cardiac electrophysiologystudies began as diagnostic studies. Thepast decade has seen the introduction ofseveral new treatments which havebroadened the scope of invasive electro-physiology studies. In particular, thedevelopment of catheter ablation tech-niques increasingly allows curativetreatment to be delivered in the catheterlaboratory.The workload of electrophysiological

procedures has steadily increased in ourtertiary referral centre. Over 1000patients have been treated in the past 20years and it is projected that 219 newpatients will be treated in 1991 and 342procedures will be carried out. Over 25%of patients now receive either catheter orsurgical ablation and almost 80% of theseare cured permanently without the needfor further drug treatment. The develop-ment of safer techniques for catheterablation has led to its increased use and adecline in surgical ablations. Becausecatheter ablation is a much simpler andless traumatic procedure than surgicalablation there are great advantages bothfor the patient and in terms of cost-effectiveness. Antitachycardia pacing,relatively common in 1985, has nowlargely been supplanted by ablation andimplantation of defibrillators.As the tendency to non-pharmaco-

logical treatment increases and evidencemounts that cost-effectiveness is greaterfor electrophysiological treatments, theimplications for the funding of electro-physiology services grow. The initiallyhigh cost of curative treatment needs tobe balanced against the longer term andpotentially higher costs of palliative drugtreatment. The potential to cure patientswith catheter procedures may lead to agreater demand for this expertise and aneed for an increase in training andfacilities.

The investigation of cardiac arrhythmias was

revolutionised by the introduction of invasiveelectrophysiological (EP) methods in the late1960s which clarified mechanisms of arrhyth-

mia and the methods by which accessory path-ways and reentrant circuits could be localised.The role of electrophysiological studies becameestablished as a method of confirming thearrhythmia mechanism and substrate, testingantiarrhythmic medications, and as a pre-requisite for surgical ablation or implantationof an antitachycardia pacemaker.

Therapeutic options have been extended bythe availability of cardiac transplantationand implantable cardioverter-defibrillators.However, because of the advent of catheterablation in the 1980s' the role of the electro-physiological study itself has become extendedinto a directly therapeutic procedure, withimplications for the treatment of a wide varietyof cardiac arrhythmias.We have reviewed the numbers of patients

treated by invasive electrophysiologicalprocedures and in particular the trend towardscurative treatment and away from drug treat-ment over the past six years in a tertiary referralcentre with a specialist cardiac electro-physiological service.

MethodsThe first electrophysiological study was perfor-med in the National Heart and BromptonHospitals in March 1971. These hospitalsfunctioned as a secondary and tertiary referralcentre supplying a wide range of cardiologicalservices to many health authorities. Since 1971over 1000 patients have undergone more than1400 invasive procedures for the diagnosis,control, or cure of cardiac arrhythmias. Thenumber remained small until mid 1984, when afull-time clinician with an interest in arrhyth-mias was appointed. Since then both the num-ber ofprocedures and the treatments used havegrown steadily, though a temporary reductionwas seen during 1989-90 when the hospitalsamalgamated (to form the Royal BromptonNational Heart and Lung Hospital, Chelsea)and laboratory access was temporarily restric-ted. These restrictions ended in December1990.The number and type of invasive electro-

physiological procedures performed from 3March 1971 to 9 May 1991 was obtained fromthe following sources: (a) a computeriseddatabase of all catheter laboratory proceduresin the Brompton and National Heart Hospitals

99

Departments ofBiomedicalEngineering andPacing &Electrophysiology,Royal BromptonNational Heart andLung Hospital, LondonD CunninghamE Rowland

Correspondence to:Dr David Cunningham,Department of BiomedicalEngineering, RoyalBrompton National Heartand Lung Hospital, SydneyStreet, London SW3 6NP.

Accepted for publication4 October 1991

on June 19, 2020 by guest. Protected by copyright.

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Cunningham, Rowland

(currently held in Orchids* database on an in-house Hewlett Packard 9000 supermini com-puter); (b) a log book of all invasive procedures(maintained by the pacing and electro-physiology physiological measurement tech-nicians); and (c) a computerised database of allablative and implantable device procedures(held in the EPSt database on MS-DOS 386desktop computers).

All data from all sources were coded by aunique hospital number. The data were extrac-ted from the computerised sources and impor-ted into a Lotus 1-2-3 spreadsheet running ona 386-compatible desktop computer. The out-come and complication data for the ablationprocedures were provided by in-built reportgenerators in EPS.The types of electrophysiological procedure

were classified as follows:(a) Diagnostic-To provoke and study

mechanisms of clinical arrhythmia and assessthe effects of pharmacological or non-pharmacological treatment.

(b) Flutter conversion-To convert spontan-eously occurring atrial flutter.

(c) Antitachycardia pacemaker implant.(d) Catheter ablation.(e) Surgical ablation.(f ) Implantable cardioverter defibrillator

implant.In addition, each procedure was classified as

primary ifperformed on a patient who had hadno previous invasive electrophysiologicalprocedure of any kind or secondary if precededby an electrophysiological procedure of anykind. Thus most procedures of types (c) to (f )(above) were secondary, because they werepreceded by a diagnostic electrophysiologicalstudy. Similarly, restudy after ablation or drugtreatment was a secondary procedure. Thetotal number ofprimary procedures is the sameas the number ofnew patients.Any secondary procedures carried out at the

bedside are not recorded in the sources listedabove and are therefore not included in thisstudy. These account for a significant numberof repeat electrophysiological procedurescarried out on patients undergoing serial elec-trophysiological-guided drug testing (via sin-gle wires left in situ after primary electro-physiological study) and on patients testedafter sugical ablation (via epicardial wiresplaced at operation). We recognise that thenumber of procedures recorded under "diag-nostic electrophysiological study" will be anunderestimate.To place the 1991 workload in the context of

previous years, the number ofprocedures from

*Orchids (Oracle-based Rebtional Cardiology Hospital Infor-mation Database System) is a distributed relational databasedeveloped to run under Oracle by DrA F Ricards at the RoyalBrompton National Heart and Lung Hospital. It can run onmainframe, mini, or personal computers. Currently, Orchidscovers all in-patient cardiological data with the exception ofinvasive electrophysiological procedures, which is a planedfuture expansion.tEPS is a stand alone relational database running on individualdeshop computers. It was developedunderDataee byDrADCunningham at the Royal Brompton National Heart and LungHospital and can transfer data to Orchids if necessary. It allowsstorage of overview data for all invasive electrophysiological

procedures, with in depth modules covering catheter andsurgical ablation.

1 January 1991 to 9 May 1991 was extrapolatedto provide a figure for the whole of 1991, basedon the number ofworking days available in thelaboratory and taking into account the possibleexaggeration caused by any backlog that hadbuilt up by the end of 1990.

ResultsALL ELECTROPHYSIOLOGICAL PROCEDURESIn the 20 year period March 1971-May 1991,1009 patients had 1428 invasive electro-physiological procedures. Figures 1 and 2 showthe annual number of procedures and newpatients. The mean number of patients andprocedures per year between 1971 and 1983(inclusive) was 10 and 11 respectively. Thesefigures increased to 110 and 165 between 1984and the end of 1990, and correspond to theappointment of a full-time cardiac electro-physiologist. At the time of writing, we projectthat in 1991, after the opening of a dedicatedlaboratory, we will treat 219 new patients andundertake 342 procedures.

Before 1984 all electrophysiologicalprocedures were diagnostic with the exceptionof two antitachycardia pacemaker implants.Catheter ablation was introduced in 1984,surgical ablation and flutter conversion in 1985,and an implantable defibrillator implant in1988. Antitachycardia pacemaker implantswere increased from 1985 onwards. Figure 3shows the breakdown of the total electro-physiological procedures into the six specifictypes. Table 1 shows the data for primary andsecondary procedures in these types.

ABLATIVE PROCEDURES: NUMBERSFigure 4 shows the percentage ofnew patientsundergoing all ablative procedures since theirintroduction. This increased steadily from1985, until ablative procedures represented>30% of all procedures in 1989 and 1990. In1991 the figure dropped to just under 25%.Inspection of aggregate figures in table 1showed that the total number of ablationscontinued to rise in 1991, but there was a dropin diagnostic electrophysiological studies in1989-90 with no decrease in ablativeprocedures.

Figure 5 shows the numbers of catheter andsurgical ablations. Although it was introducedto these hospitals a year earlier, catheter abla-tion was rapidly overtaken by surgical ablationfrom 1985 to 1988. In 1988, the number ofsurgical ablations was nearly double the num-ber of catheter ablations. There was a sharpreversal from 1989 to the present day, withincreasing numbers of catheter procedures atthe expense of surgical ablations. At present,there are three times as many catheter ablationsas surgical ablations.

Catheter ablation of ventricular tachycardiaremains at a relatively low level (a total of 21procedures between 1985 and the end of 1990)like surgical ablations of ventricular tachycar-dia in the same period.'o In contrast, ablation ofsupraventricular tachycardia has becomeincreasingly successful with catheter tech-niques, and we project that 48 procedures will

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Impact of catheter and surgical ablation on arrhythmia treatment in a tertiary referral centre

be performed by a catheter technique in 1990(project d) compated with 16 by a surgical one. This

342 compares with eight catheter and 23 surgicalprocedures in 1988.

I I T

71 73 75 77 79 81 83 85 87 89 91Year

Figure 1 Annual number ofprocedures between 1971 and 1991. There was aconsiderable increase after the appointment of afull-time electrophysiologist in 1984.Figuresfor 1991 are projectedfrom current workload.

(projected)219

133120123 114

50' 34 36

126 3 2 9 2 3 0 10

71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91Year

Figure 2 Number ofpatients peryear treatedfor thefirst time with invasiveelectrophysiological procedures. Workload increased steadily since 1984 apartfromartificial restrictions in 1989-90 (see text).

Figure 3 Breakdown ofproceduresfrom 1983 to1991 shows the steady risein catheter ablations, theincrease inantitachycardiapacemakers and sugicalablationsfrom 1985 to1988 which has now beenreversed, and the slowemergence of implantationof cardioverterldefibrillators.

_ Implantable cardioverteridefibrillator

a Surgical ablation

_ Catheter ablation

BE Antitachycardia pacemaker

M Flutter conversion

= DiagnosticI

83 84 85 86 87 88 89 90 91Year

OTHER FORMS OF NON-PHARMACOLOGICALTREATMENTAntitachycardia pacing was at its peak in 1987-89, and was used almost exclusively as atreatment for atrioventricular nodal reentranttachycardia. Only one patient has had a deviceimplanted since 1989. (This was a patient withslow ventricular tachycardia which could notbe ablated by catheter. Because the patient wasnot a suitable candidate for any surgicalprocedure owing to very poor left ventricularfunction, the pacemaker was implanted as a lastresort. The patient's ventricular tachycardiawas controlled but he died of progressive heartfailure nine months later.) Since 1988, implan-table cardioverter/defibrillators have increasedslowly. A total of 13 patients have currentlybeen implanted with 14 devices.Two patients in our series received a cardiac

transplantation for severe cardiomyopathycomplicated by intractable ventriculartachycardia and ventricular fibrillation.

PATIENT FLOWFigure 6 shows the treatment received by the1009 patients who underwent invasive electro-physiological procedures: 776 were eithertreated with drug treatment alone or did notrequire treatment. The remaining 233 hadsome form of interventional procedure. Thereis a complex flow of patients between the formsof non-pharmacological treatment, but severalpoints are worthy of note.

(a) Forty one patients were referred directlyfor catheter ablation without a primary diag-nostic electrophysiological study. Most oftheseunderwent ablation of atrioventricular conduc-tion for control of drug-refractory atrialfibrillation or flutter.

(b) In the last year, however, an increasingnumber of patients have had a diagnosticelectrophysiological study for atrioventricularnodal reentrant tachycardia or atrioventricularreentrant tachycardia and have progressedimmediately to catheter ablation.

(c) Sixty nine patients were referred forcatheter ablation after a primary electro-physiological study and two had a flutter con-version procedure before catheter ablation.

(d) Of 114 patients referred for catheterablation, 13 (11%) subsequently underwentsurgical ablation.

(e) Two patients who underwent surgicalablation before 1990 have recently had catheterablations. One had successful surgical ablationof ventricular tachycardia but after 18 monthspresented with a new clinical ventriculartachycardia which was successfully ablated bycatheter. The second patient initially had anexcellent result after surgical ablation of ananteroseptal accessory pathway and simultan-eous cryosurgical modification of a slowatrioventricular nodal pathway for cure ofatrioventricular nodal reentrant tachycardia.Atrial flutter then occurred three months

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Table 1 Annual workloads for invasive electrophysiology procedures

Flutter Antitachycardia Catheter SurgicalDiagnostic conversion pacemaker ablation ablation ICD implant

Year 1P 2° 1P 2° I' 2 P1° 2° 1P 2° 1P 2°

pre-1984 130 7 0 0 5 3 0 0 0 0 0 01984 50 0 0 0 1 1 3 0 0 0 0 01985 115 9 3 0 8 6 7 0 2 0 0 01986 113 15 4 1 3 1 13 7 12 0 0 01987 113 33 1 1 1 3 0 8 3 13 0 0 01988 122 40 6 2 2 0 13 4 25 0 2 01989 95 26 6 1 2 0 27 11 21 0 5 01990 90 26 7 1 3 0 25 7 19 0 4 11991 (projected) 192 58 11 0 0 0 50 13 16 0 2 0

1°, primary procedure; 2°, secondary procedure; ICD, implantable cardioverter/defibrillator.

35 / postoperatively, and was conducted via the

C Surgical ablation single remaining atrioventricular nodal path-30 LIE Catheter ablationX-_ way with intermittent 1: 1 response. Because

,Catetealatothe patient remained refractory to medication,catheter ablation was used to create complete

25 heart block. A further patient who failed sur-gical ablation of an accessory pathway atc> 201 H I H 1 01 1 1 1another United Kingdom centre has also had

o20Xu JiMsuccessful catheter ablation recently.15 (f) Ofthe 12 patients receiving implantable

L 15 -/ / S W S cardioverter/defibrillators, 10 were referreddirect from diagnostic electrophysiological

10 ~~~~~~~~~~~~~~~~~study,one had a failed catheter ablation, andlo ~~~~~~~~~~~~~~~~~~onea failed surgical ablation.(g) Seven hundred and seventy six patients

5 (77%) were managed by drug treatment aloneor required no treatment. Many of these

0 patients underwent serial electrophysiological83 84 85 86 87 88 89 90 91 testing, although some of these procedures

Year were carried out at the bedside via a single wireleft in situ after the primary electro-

Figure 4 Percentage ofpatients undergoing definitive ablative treatment increased h * * * -

from zero in 1983 to 30% in 1989-90. Number ofprocedures continues to increase in p iysiological study. These bedside studies are1991, although an increase in diagnostic electrophysiological studies reduced the not included in the procedure numbers in fig 6.proportion of ablative procedures to 25%.

ABLATIVE PROCEDURES: RESULTSOne hundred and ninety seven patients had oneor more ablative procedures. Ninety nine had1-4 catheter ablation sessions; 83 had a singlesurgical ablation session; 13 had surgical abla-tion after failed catheter ablation; and two had

20 catheter ablation after previous surgical abla-M Catheter ablation tion, as discussed above. The overall results0 Surgical ablation were complete cure in 155 (79%), control of

arrhythmia by a previously ineffective drug15 treatment in 10 (5%), failure in 28 (14%), and

procedure-related death in three (1 5%) (table2).

Tables 3 and 4 show the individual results forcatheter and surgical ablation of different arr-

o-0-1lo 1;hythmias. Overall, catheter ablation was suc-

cessful in 59%, with minimal complications.Surgical ablation had a higher success rate(89%) but there were serious complications in

5 10%. All three surgical failures to divide acces-sory pathways occurred within the first twoyears of experience. No patients required arepeat surgical ablation whereas multiple cath-

o eter ablation sessions were required in 25-4%83 84 85 86 87 88 89 90 91 of patients.

YearDiscussion

Figure 5 Relative number ofpatients undergoing catheter or surgical ablation shows FACTORS AFFECTING TOTAL NUMBER OFsurgical procedures overtaking catheter procedures from 1985 to 1988 and then aprogressive decline in surgical procedures accompanied by a sharp rise in catheter ELECTROPHYSIOLOGICAL PROCEDURESablations. As one would expect, there was a major

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Figure 6 Flow of 1009patients undergoing 1428invasiveelectrophysiologicalprocedures over a 20yearperiod shows that mostpatients require notreatment or only drugtreatment. However, an

increasing number receivenon-pharmacologicaltreatment, in particularablative procedures. Mostof these have had a priordiagnosticelectrophysiological study,but there is a recent trendtowards combining the twointo a single study. This isboth convenientfor thepatient and highly cost-effective. Antitachycardiapacemakers are no longerused, having been replacedby ablation andimplantation of acardioverter/defibrillator.

;1 /11 1 1 2

CARDIAC ICD IMPLANT 1 SURGICALTRANSPLANTATION 13 patients/14 procedures _ ABLATION

2 patients/2 procedures 98 patients/procedures

increase in the number of electrophysiologicalprocedures after a full-time cardiac electro-physiologist was appointed midway through1984. There has also been a progressiveincrease in total procedures since that timebecause of increasing clinical demand.

IMPLANTABLE DEVICESAntitachycardia pacing was at its peak in 1985-87 and was used almost exclusively as a treat-ment for atrioventricular nodal reentranttachycardia. Since that time, surgical and thencatheter techniques have increasingly offered apotential cure for this arrhythmia and have nowcompletely supplanted the use of antitachycar-dia pacing in our hospital. In patients withventricular arrhythmias that cannot be con-trolled by drugs or cured by an ablativeprocedure, the implantable cardioverter/defibrillator, with or without an antitachycar-dia pacing capability, offers a much more

secure treatment than antitachycardia pacingalone, because of risk of tachycardia accelera-tion. (Many of the present generation of"tiered-therapy" implantable cardioverter/defibrillator devices incorporate antitachycar-dia pacing modes as the primary treatment forhaemodynamically tolerated ventriculartachycardia, and the future role of the standalone antitachycardia pacemaker is thereforeprobably very small in centres such as ours.)

ABLATIVE PROCEDURESTable 2 shows that nearly 80% of patients whowere treated by catheter and/or surgical abla-tion were completely cured without the needfor drug treatment. Catheter ablation was usedwith enthusiasm in its early stages, but somedisillusionment with poor results led to itspartial decline in 1987-88, as shown by therelatively higher number of surgical ablationsat that time (fig 5). However, improvements in

Table 2 Overall results of ablative procedures

Controlled bypreviously Procedure-

Number of ineffective drug relatedProcedure ofpatients Cured (%) treatment (%) Failed (%) death (%)

Catheter ablation alone 99 66 (67) 9 (9) 24 (24) 0Catheter then surgical ablation 13 9 (69) 1 (8) 1 (8) 2 (15)Surgical ablation alone 83 78 (94) 0 3 (4) 2 (2)Surgical then catheter ablation 2 2 (100) 0 0 0Total 197 155 (78-7) 10(5-1) 28(14-2) 4(2 0)

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Table 3 Results of catheter ablation


Number of ineffective drug relatedProcedure ofpatients Cured treatment Failed death (%)

Accessory pathway 38 21 4 13 0Ventricular tachycardia 15 5 3 7 0Atrial tachycardia 2 0 0 2 0Ablation ofAV conduction 52 40 3 9 0Modification ofAV conduction 5 1 0 4 0Atrial flutter 2 0 0 2 0Total 114 67 (58 8%) 10 (8 8%) 37 (32 5%) 0

Serious complications (3): coronary sinus rupture (1) (after high energy catheter ablation of posteroseptal accessory pathway inthe coronary sinus os. Surgically repaired in catheter laboratory) and ventricular fibrillation (2). AV, atrioventricular.

Table 4 Results of surgical ablation


Number of ineffective drug relatedProcedure ofpatients Cured treatment Failed death (%)

Accessory pathway 68 64 0 3 1Ventricular tachycardia 20 14 1 3 1Atrial tachycardia 4 3 0 0 0Ablation ofAV conduction 4 3 0 0 1Modification ofAV conduction 2 2 0 0 0Total 98 87 (88-8%) 1 (1 0%) 6 (6-1%) 3 (2-9%)

Serious complications (10): procedure-related death (3) (low output state after bypass (2 h) followed by accessory pathwayablation, progressive cardiac failure (3 days) followed by VT ablation, septicaemia (7 days) followed by ablation of AVconduction); late deaths (1) (sudden cardiac death (6 months) followed by VT ablation); severe CVA (2); complete heart blockafter accessory pathway dissection (1); acute congestive heart failure (1); atrial flutter with 1:1 atrioventricular conduction (1);right leg amputation (1).AV, atrioventricular, VT, ventricular tachycardia; CVA, cerebrovascular accident.

technology (the development of a low-energyablation power source2 and catheter3 and tech-nique (particularly the use of retrograde aorticcatheterisation to approach left sided accessorypathways4 led to improved results andincreased enthusiasm from 1989 onwards. As aresult, catheter ablation procedures in the pastthree years have had a success rate approaching80% and now outnumber surgical ablations3: 1. Such a ratio is likely to persist or evenincrease as ablation methods which do notrequire a general anaesthetic (such asradiofrequency5) are increasingly used.Radiofrequency ablation was introduced in ourhospital in 1990, and our early results suggestthat its success rate is comparable to low or highenergy DC ablation for accessory pathwayablation. Other workers' experience6 suggeststhat it may be a less useful technique for thecreation ofa complete heart block or ablation ofventricular tachycardia, but it is probably thetechnique of choice67 for modification of theatrioventricular node in cases of atrioven-tricular nodal reentrant tachycardia.

Early on, when we were using high energiesand conventional pacing catheters for ablation,cardiac tamponade was caused in one patient byrupture of the coronary sinus during attemptedablation of a posteroseptal accessory pathway.This experience and similar reports from othergroups gave us the impetus to develop safermethods ofcatheter ablation.23 Our fundamen-tal strategy is to err on the side of safety duringcatheter ablation, thus making it a safe andreasonably effective procedure, and thereforeworth attempting before proceeding to opera-tion in almost all patients. In our practice, it isthe treatment ofchoice for ablation ofaccessory

pathways as well as for the creation of completeheart block, and it remains worth attempting insome selected cases of ventricular tachycardia.Surgical treatment has been preferred to cath-eter modification of atrioventricular nodal con-duction in the treatment of atrioventricularnodal reentrant tachycardia and for ablation offocal atrial ectopic tachycardia. We have,however, begun to gain experience in attempt-ing modification of atrioventricular nodal con-duction by multiple applications ofradiofrequency energy to the region of thetriangle of Koch. Other groups have alreadyreported success with this technique, both withradiofrequency energy7 8 and conventionalshocks.9 Recently reported results for ablationof accessory pathways by radiofrequencyenergy810 1 suggest that this technique maycompletely replace surgery for this indicationin the near future.

COST EFFECTIVENESS OF CATHETER ABLATIONSignificant decreases in health care costs havebeen reported during long-term follow up ofpatients who have undergone catheter ablationof atrioventricular conduction12 13 or an acces-sory pathway.14 The number ofhospital admis-sions was greatly reduced and the need for drugtreatment was virtually eliminated. Althoughsimilar long-term studies have not been repor-ted for catheter ablation of accessory pathways,one would expect even greater savings in thesepatients because a permanent pacemaker is notrequired.Used as described above, we believe that

catheter ablation is an extremely valuable,minimally traumatic, and cost-effective tool forthe management of arrhythmias. Because the

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Impact of catheter and surgical ablation on arrhythmia treatment in a tertiary referral cent?

option of surgical ablation is available we can

use catheter ablation with caution, maximisingits safety and allowing it to be used not only as a

treatment of last resort.

PHARMACOLOGICAL TREATMENT VERSUS NON-PHARMACOLOGICAL TREATMENTMost (77%) patients in this study required no

treatment or received drug treatment alone,guided by serial electrophysiological testingwhere appropriate. However, this global figuremasks a trend away from pharmacologicaltreatment over the past few years, and over

30% of patients now receive one or otherform of non-pharmacological treatment.Increasingly we are turning away frompharmacology and towards attempting to cure

arrhythmias with ablation or to palliate themwith devices that we hope are more cost-effec-tive than drug treatment. It is unfortunate thatwe are not in a position to compare the efficacyand cost-effectiveness of pharmacological andnon-pharmacological treatments, and it will bea prime requirement to attempt to make suchjudgements when our new information systemsare in place. Meanwhile, resource limitations(both in terms of laboratory time and devicefunding) will be the principal limitation on our

use of non-pharmacological treatmentstrategies. The present data indicate that thelimit lies at around 30-35% of all patientsreferred for invasive electrophysiologicalstudy.

Clearly drug treatment may be more expen-sive over the lifetime of a patient but theexpense is spread out over years. Non-phar-macological treatment, particularly deviceimplantation, is much more expensive initiallyand then much less expensive as time goes by.It is therefore more cost-effective if the patientsurvives for a long period, but the initial outlayis much greater and provision for costing andcomparing such contrasting treatments needsto be made to enable referring physicians tomake an informed and sensible choice.

ELECTROPHYSIOLOGICAL PROCEDURES IN THE

CONTEXT OF GENERAL CARDIOLOGICAL CARE

It would have been interesting to examine thereferral patterns of patients for invasive elec-trophysiological procedures within our hosp-itals and their relation to the advances intreatment and also to the clinical outcome ofthese patients; however, with the exception ofpatients who had ablation, antitachycardiapacemakers and implantable cardioverter/defibrillators, clinical outcome data were notavailable, nor were retrospective referral pat-tems. All of these data will be available prosp-ectively, however, with the introduction ofnewadministrative and clinical computing systems

re 105

in 1990-92; it will then be possible to assess thetrue impact on clinical outcome, quality of life,and cost-effectiveness of different treatmentsfor cardiac arrhythmia.

Until then this present review indicates thatthe demand for invasive electrophysiologicalprocedures within our hospitals continues toincrease, and the resumption of this increase in1991 after artificially imposed restrictions in1989-90 shows little tendency for the curve toflatten out. It may well be that the clinical needfor these procedures exceeds the servicesprovided nationally in the United Kingdomand that the number of procedures that we areable to perform will therefore always remainresource-limited. If that is the case, andprovided cost-effectiveness can be demon-strated, then consideration should be given toincreasing the availability of these services,both by training more cardiac electro-physiologists and by providing a larger numberof specialist centres with facilities to provide allof these treatments.

1 Scheinman MM, Morady F, Hess DS, Gonzalez R.Catheter-induced ablation of the atrioventricular junctionto control refractory supraventricular arrhythmias.JAMA 1982;248:851-5.

2 Cunningham D, Rowland E, Rickards AF. A new lowenergy power system for catheter ablation. PACE 1986;9:1384-90.

3 Ahsan AJ, Cunningham D, Rowland E, Rickards AF.Catheter ablation without fulguration: design and perfor-mance of a new system. PACE 1989;12:1557-61.

4 Warin J-F. Catheter ablation of accessory pathways: tech-nique and results in 248 patients. PACE 1990;13:1609-14.

5 Huang SK, Bharati S, Graham AR, Lev M, Marcus FI,Odell RC. Closed-chest catheter ablation of the atrioven-tricular junction using radiofrequency energy: a newmethod of catheter ablation. J Am Coll Cardiol1987;9:349-58.

6 Cunningham D. High energy catheter ablation of cardiacarrhythmias: an outmoded technique in the 1990s. ClinCardiol 1991;14:595-602.

7 Lee MA, Morady F, Kadish A, et al. Catheter modificationof the atrioventricular junction with radiofrequencyenergy for control of atrioventricular nodal reentrytachycardia. Circulation 1991;83:827-35.

8 Calkins H, Sousa J, El-Atassi R, et al. Diagnosis and cure ofthe Wolff-Parkinson-White syndrome or paroxysmalsupraventricular tachycardia during a single electro-physiological test. N Engl J Med 1991;324:1612-8.

9 Haissaguerre M, Warin JF, Lemetayer P, Saoudi N,Guillem JP, Blanchot P. Closed-chest ablation ofretrograde conduction in patients with atrioventricularnodal reentrant tachycardia. N Engl J Med 1989;320:426-33.

10 Jackman WM, Wang X, Friday KJ, et al. Catheter ablationofaccessory atrioventricular pathways (Wolff-Parkinson-White syndrome) by radiofrequency current. N Engl JMed 1991;324:1605-11.

11 Kuck K-H, Schluter M, Geiger M, Siebels J, Duckeck W.Radiofrequency current catheter ablation of accessoryatrioventricular pathways. Lancet 1991;337:1557-61.

12 Kay GN, Bubien RS, Epstein AE, Plumb VJ. Effect ofcatheter ablation of the atrioventricular junction onquality of life and exercise tolerance in paroxysmal atrialfibrillation. Am J Cardiol 1988;62:741-4.

13 Rosenqvist M, Lee MA, Moulinier L, et al. Long-termfollow-up of patients after transcatheter direct currentablation ofthe atrioventricular junction. JAm Coll Cardiol1990;16:467-74.

14 de Buitleir M, Bove EL, Schmaltz S, Kadish AH, Morady F.Cost of catheter versus surgical ablation in the Wolff-Parkinson-White syndrome. Am J Cardiol 1990;66:189-92.



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Impact of catheter surgical ablation on arrhythmia in ... · requisite for surgical ablation or implantation ofanantitachycardia pacemaker. Therapeuticoptions havebeenextendedby the