This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wellens, H. J. J. Search for Related Content PubMed PubMed Citation Articles by Wellens, H. J. J. Pubmed/NCBI databases Medline Plus Health Information Arrhythmia Related Collections Other Treatment Arrhythmias, clinical electrophysiology, drugs

(Circulation. 1999;99:195-197.)
© 1999 American Heart Association, Inc.

Editorial

Catheter Ablation of Cardiac Arrhythmias

Usually Cure, but Complications May Occur

Hein J. J. Wellens, MD

From the Department of Cardiology, Academic Hospital Maastricht, Netherlands.

Correspondence to Hein J.J. Wellens, MD, Department of Cardiology, Academic Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, Netherlands.

Key Words: Editorials • catheter ablation • arrhythmia

In cardiology, our ability to cure is rare. When cardiac disease is diagnosed, most of our treatments are palliative. They may remove or diminish complaints and prolong life but usually will not be able to stop the disease process. Cure is possible, however, in the patient suffering from a tachycardia in an otherwise normal heart. In that patient, we can locate the site of abnormal impulse formation or a critical part of the tachycardia pathway by cardiac activation mapping during the arrhythmia. Through the same or another catheter, radiofrequency (RF) energy can be applied to that area, resulting in destruction of a few millimeters of critical tissue and cure of the patient. That technique has been with us now for a decade.^{1 2 3 4} During that decade, RF energy applied through a catheter has been shown to be very effective in different types of supraventricular tachycardia.

A method can be effective, but its use may be limited because of complications. The key question, therefore, is, how safe is RF catheter ablation in the treatment of patients with arrhythmias? Certain risks are associated with RF ablation. They include the general risks of any cardiac catheterization, such as thromboembolic complications, infection, bleeding, cardiac perforation with or without cardiac tamponade, valvular damage, and radiation damage. In addition, specific risks are related to the ablation procedure itself.

To abolish the substrate of an arrhythmia, a small area of myocardial necrosis is necessary. It is difficult, however, to assess in vivo the amount of tissue destroyed by RF ablation. Several investigators have looked at the value of biochemical markers to estimate the amount of myocardial necrosis after ablation. Haines et al⁵ showed that measurement of the creatine activity significantly underestimated the volume of myocardial injury because creatine kinase (CK) activity is not stable at temperatures >65°C, which are routinely attained within the central zone of RF ablation. A better marker to assess the size of necrosis seems to be the release of cardiac troponin I. Madrid et al⁶ found elevated values in 44 of 46 patients after RF ablation. In their studies, cardiac troponin I release varied according to the site in the heart (atrium, AV node, accessory pathway, ventricle) at which the RF ablation was applied, was moderately related to the number of RF pulses, and reached a peak value 8 hours after ablation. Madrid et al found that cardiac troponin I had the greatest sensitivity (better than that of CK and CK-MB) for detecting minor myocardial damage. It is important to know that in vivo studies could not demonstrate a good correlation between lesion size as found at autopsy and the amount of energy delivered during ablation, the duration of RF application, and the degree of catheter contact.^{7 8 9} More information about the value of cardiac troponin I to estimate cardiac damage after RF ablation is needed to obtain a better idea about the size of the area of necrosis, especially after multiple RF applications or the drawing of long ablation lines, as in atrial fibrillation.

When myocardial necrosis occurs during application of RF energy in a specific area like the atrioventricular (AV) node, complete AV block may occur. This has occurred more commonly in the so-called anterior approach to AV nodal tachycardia ablation, in which the AV nodal fast pathway is ablated rather than slow pathway ablation.¹⁰ In patients with accessory AV pathways (APs), the risk of catheter ablation is related to the location of the accessory pathway. Ablation of a para-Hisian accessory pathway carries the risk of complete AV block. In epicardially located posteroseptal or left posterior bypasses, in which ablation has to be performed from the coronary venous system, there is the risk of damage to the coronary artery or perforation of the venous system, leading to cardiac tamponade. Also, in right free wall accessory pathways, the right coronary artery may be damaged.

How dangerous, therefore, is the application of a catheter ablative procedure in patients with a cardiac arrhythmia?

That question was addressed in the prospective multicenter study by Calkins et al¹¹ in this issue of Circulation. A total of 1050 consecutive patients participating in the clinical evaluation of a new RF catheter ablation system were included in the study. Ablation was performed in 50% of the patients because of an accessory AP, in 33% of the patients because of AV nodal reentrant tachycardia (AVRNT), and in 121 patients to interrupt conduction in the AV junction. Catheter ablation was successful in 95% of patients (100% in AV junction ablation, 97% in AVRNT, and 93% in APs). Within 1 month of the ablation, 3% of patients developed a major complication (such as death, stroke, myocardial infarction, complete AV block), and 8.2% a minor complication.

Complications occurred in all 3 groups of patients (AVNRT, AP, and AV junction) and were more common in patients with structural heart disease and multiple ablation targets. That they were found in patients who underwent ablation of the AV junction is not surprising. These patients more often have associated cardiac disease with diminished cardiac function. But complications also occurred in the patients with AVNRT and accessory AV pathways. There was a 1.3% (5 of 373 patients) and 1% (5 of 500 patients) incidence of complete AV block in patients with AVNRT and accessory pathways, respectively. It is not clear whether all patients with AVNRT underwent ablation of the slow AV nodal pathway (the study was performed between 1992 and 1995). Of the minor complications listed in Table 4 of the article by Calkins et al,¹¹ no information is given as to their effect on length of hospital stay and the financial consequences. Recurrences of arrhythmias occurred primarily in the patients with right free wall, posteroseptal, septal, and multiple accessory pathways and were found in 6% of the patients. These locations of accessory pathways more likely to have arrhythmia recurrences are well known and are related to greater difficulty in obtaining correct catheter-tissue contact to achieve adequate tissue heating.

The findings on complications of RF ablation from the prospective multicenter study by Calkins et al are not very different from those found in the earlier Multicenter European Radiofrequency Survey reported by Hindricks.¹² In that retrospective study, in which 2222 patients with accessory APs were treated by catheter ablation in the years 1987 to 1992, 14 patients (0.63%) developed complete AV block, 16 patients (0.72%) cardiac perforation with or without tamponade, and 12 patients clinically significant pericardial effusion. In 3 patients, death was thought to be related to the procedure. Both Calkins et al and Hindricks indicate that patient load and the experience of the center at which the ablation is performed are important determinants of success and complication rate.

The study by Calkins et al¹¹ shows that RF catheter ablation can be performed with a high degree of success in patients with AVNRT and accessory APs. But in view of the sometimes serious complications, catheter ablation should be suggested only when the tachycardias are symptomatic and interfere with the well-being of the patient. The procedure should be performed in specialized centers by clinical electrophysiologists with extensive experience in the investigation of patients with AVNRT and accessory AV pathways. In patients with accessory pathways in the right free wall, epicardial posteroseptal, epicardial left posterior, and para-Hisian locations, the threshold to perform ablation should be higher, because of the higher incidence of complications. Rarely will there be an indication for catheter ablation in the asymptomatic patient with AV conduction over an accessory pathway, probably only in the case of an occupational hazard (airline pilot, bus driver, or athlete). In the patient with an accessory pathway who has rare and well-tolerated episodes of tachycardia, the value of vagal maneuvers should be explained and pharmacological treatment, either intravenous or oral, given only when the tachycardia cannot be terminated by a vagal maneuver. For intravenous use, adenosine or verapamil is preferred for an orthodromic circus movement tachycardia and procainamide for atrial fibrillation. For oral drug treatment, sotalol or class Ic drugs can be used.

In the patient with AVNRT, RF modification of AV nodal conduction carries the risk of AV block. Therefore, patients are instructed about vagal maneuvers, and long-term drug therapy is prescribed only when tachycardias are frequent and poorly tolerated. If therapy with drugs such as digoxin, calcium antagonists, or ß-blockers is not succesful or not tolerated, RF catheter treatment is advised. As in the patient with an accessory pathway, in case of a rare and well-tolerated AVNRT, drug treatment is given only when a tachycardia occurs following an approach similar to that discussed under circus movement tachycardia.

It is important to note that in the study by Calkins et al,¹¹ no differences were found between children and adults with regard to success and complications. Previously, concern was expressed about RF ablation in the small child because of a possible increase in size of the RF lesion when the heart enlarges,¹³ and it was considered prudent to abstain from an RF intervention until the child had reached the age of 10 years.¹⁴ However, current information suggests that ablation should be postponed until the child weighs >15 kg.¹⁵

In conclusion, RF ablation usually results in cure in patients with supraventricular tachycardia. However, the possibility of complications should always be considered. The information from the study by Calkins et al¹¹ is helpful in making a risk profile for the individual patient.

Footnotes

The opinions expressed in this editorial are not necessarily those of the editors or of the American Heart Association.

References

1. Jackman WM, Xunzhang W, Friday KJ, Roman CA, Moulton KP, Beckman KJ, McClelland JH, Twidale N, Hazlitt HA, Prior MI. Catheter ablation of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome) by radiofrequency current. N Engl J Med. 1991;324:1605–1611.[Abstract]
   
2. Calkins H, Sousa J, El-Atassi R, Rosenheck S, DeBuitleir M, Kou WH, Kadish AH, Langberg JJ, Morady F. Diagnosis and cure of the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardias during a single electrophysiologic test. N Engl J Med. 1991;324:1612–1618.[Abstract]
   
3. Kuck KH, Schluter M, Geiger M, Siebels J, Duckeck W. Radiofrequency current catheter ablation of accessory atrioventricular pathways. Lancet. 1991;337:1557–1561.[Medline] [Order article via Infotrieve]
   
4. Lee MA, Morady F, Kadish A, Schamp DJ, Chin MC, Scheinmann MM, Griffin JC, Lesh MD, Pederson D, Goldberger J, Calkins H, DeBuitleir M, Kou WH, Rosenheck S, Sousa J, Langberg JJ. Catheter modification of the atrioventricular junction with radiofrequency energy in patients with atrioventricular nodal reentry tachycardia. Circulation. 1991;83:827–835.[Abstract/Free Full Text]
   
5. Haines DE, Whayne J, Waker J, Nath S, Bruns D. The effect of radiofrequency catheter ablation on myocardial creatine kinase activity. J Cardiovasc Electrophysiol. 1995;6:79–88.[Medline] [Order article via Infotrieve]
   
6. Madrid AH, Del Rey JM, Novo L, Sanchez A, Jiménez A, Martin J, Rubi J, Ripoll E, Moro C. Biochemical markers and C-troponin I release after radiofrequency catheter ablation. approach to the size of the necrosis. In: Farré J, Moro C, eds. Ten Years of Radiofrequency Catheter Ablation. Armonk, NY: Futura Publishing Co; 1998:31–40.
   
7. Langberg JJ, Lee MA, Chin MC. Radiofrequency catheter ablation: the effect of electrode size on lesion volume in vitro. Pacing Clin Electrophysiol. 1990;13:242–251.
   
8. Huang SK, Graham AR, Wharton K. Radiofrequency catheter ablation of the left and right ventricles: anatomic and electrophysiologic observations. Pacing Clin Electrophysiol. 1988;11:449–457.[Medline] [Order article via Infotrieve]
   
9. Hindricks G, Haverkamp H, Gulker H, Rissel U, Budde T, Richter KD, Borggrefe M, Breithardt G. Radiofrequency coagulation of ventricular myocardium: improved prediction of lesion size by monitoring catheter tip temperature. Eur Heart J. 1989;10:972–984.[Abstract/Free Full Text]
   
10. Hindricks G. Incidence of complete atrioventricular block following attempted radiofrequency catheter modification of the atrioventricular node in 880 patients. Eur Heart J. 1996;17:82–88.[Abstract/Free Full Text]
    
11. Calkins H, Yong P, Miller JM, Olshansky B, Carlson M, Saul JP, Huang SKS, Liem LB, Klein LS, Moser SA, Bloch DA, Gillette P, Prystowsky E, for the ATAKR Multicenter Investigators Group. Catheter ablation of accessory pathways, atrioventricular nodal reentrant tachycardia, and the atrioventricular junction: final results of a prospective multicenter clinical trial. Circulation. 1998;98:262–270.[Abstract/Free Full Text]
    
12. Hindricks G. Complications of radiofrequency catheter ablation of arrhythmias. Eur Heart J. 1993;14:1644–1653.[Abstract/Free Full Text]
    
13. Saul JP, Hulse JE, Papagiannis J, Van Praagh R, Walsh EP. Late enlargement of radiofrequency lesions in infant lambs: implications for ablation procedures in small children. Circulation. 1994;90:492–499.[Abstract/Free Full Text]
    
14. Case CL, Gillette PC, Oslizlok PC, Knick BJ, Blair HC. Radiofrequency catheter ablation of incessant, medically resistant supraventricular tachycardias in infants and small children. J Am Coll Cardiol. 1992;20:1435–1450.
    
15. Kugler JD, Danford DA, Deal BJ, Gillette PC, Perry JC, Silka MJ, Van Hare GF, Walsh EP. Radiofrequency catheter ablation for tachyarrhythmias in children and adolescents. N Engl J Med. 1994;330:1481–1487.[Abstract/Free Full Text]
    

This article has been cited by other articles:

				B. Ghaye, D. Szapiro, J.-N. Dacher, L.-M. Rodriguez, C. Timmermans, D. Devillers, and R. F. Dondelinger Percutaneous Ablation for Atrial Fibrillation: The Role of Cross-sectional Imaging RadioGraphics, October 1, 2003; 23(90001): S19 - 33. [Abstract] [Full Text] [PDF]

				S. P. Fynn and C. J. Garratt The effectiveness of serial cardioversion therapy for recurrence of atrial fibrillation Eur. Heart J., October 1, 2002; 23(19): 1487 - 1489. [Full Text] [PDF]

				K. Perisinakis, J. Damilakis, N. Theocharopoulos, E. Manios, P. Vardas, and N. Gourtsoyiannis Accurate Assessment of Patient Effective Radiation Dose and Associated Detriment Risk From Radiofrequency Catheter Ablation Procedures Circulation, July 3, 2001; 104(1): 58 - 62. [Abstract] [Full Text] [PDF]

				P. Alboni, C. Tomasi, C. Menozzi, N. Bottoni, N. Paparella, G. Fuca, M. Brignole, and R. Cappato Efficacy and safety of out-of-hospital self-administered single-dose oral drug treatment in the management of infrequent, well-tolerated paroxysmal supraventricular tachycardia J. Am. Coll. Cardiol., February 1, 2001; 37(2): 548 - 553. [Abstract] [Full Text] [PDF]

				H. Bertram, R. Bokenkamp, M. Peuster, G. Hausdorf, and T. Paul Coronary Artery Stenosis After Radiofrequency Catheter Ablation of Accessory Atrioventricular Pathways in Children With Ebstein's Malformation Circulation, January 30, 2001; 103(4): 538 - 543. [Abstract] [Full Text] [PDF]

				A. Erdogan, J. Carlsson, S. Grumbrecht, S. Kostin, B. Schulte, M. Schlapp, J. Neuzner, and H. F. Pitschner Electrochemical potentials during radiofrequency energy delivery: a new method to control catheter ablation of arrhythmias Europace, January 1, 2001; 3(3): 201 - 207. [Abstract] [PDF]

				C. WREN Catheter ablation in paediatric arrhythmias Arch. Dis. Child., August 1, 1999; 81(2): 102 - 104. [Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wellens, H. J. J. Search for Related Content PubMed PubMed Citation Articles by Wellens, H. J. J. Pubmed/NCBI databases Medline Plus Health Information Arrhythmia Related Collections Other Treatment Arrhythmias, clinical electrophysiology, drugs