Radiofrequency ablation

FIGURE 6-2. Algorithm for the treatment of acute (top portion) paroxysmal supraventricular tachycardia and chronic prevention of recurrences (bottom portion). Note For empiric bridge therapy prior to radiofrequency ablation procedures, calcium channel blockers (or other atrioventricular [AV] nodal blockers) should not be used if the patient has AV reentry with an accessory pathway. (AAD, antiarrhythmic drugs AF, atrial fibrillation AP, accessory pathway AVN, atrioventricular nodal AVNRT, atrioventricular nodal reentrant tachycardia AVRT, atrioventricular reentrant tachycardia DCC, direct-current cardioversion ECG, electrocardiographic monitoring EPS, electrophysiologic studies PRN, as needed VT, ventricular tachycardia.)... 

Patients with hepatic-predominant disease whose disease progresses with systemic therapy may be candidates for hepatic-directed therapies such as chemoembolization, cryotherapy, or radiofrequency ablation. 

Bastide C, Garcia S, Anfossi E, Ragni E, Rossi D (2006) Histologic evaluation of radiofrequency ablation in renal cancer. European Journal of Surgical Oncology 32 980-983. 

Anticoagulation in radiofrequency ablation of atrial fibrillation and atrial flutter... 

By administering intravenous heparin immediately after introduction of the venous sheaths, hemostatic activation is significantly decreased (29). There is also a significant risk for thromboembolism in patients referred for ablation of typical AFL who have not been appropriately anticoagulated (30). Radiofrequency ablation of chronic AFL is associated with significant left atrial stunning (3 I). 

Passman R.S, et al, Radiofrequency ablation of atrial flutter a randomized controlled study of two anatomic approaches. Pacing Clin Electrophysiol 2004 27( I ) 83—88. 

Dorbala S, et al. Does radiofrequency ablation induce a prethrombotic state Analysis of coagulation system activation and comparison to electrophysiologic study. J Cardiovasc Electrophysiol 1998 9(1 l) l 152-1 160,... 

Pappone C, et al. Circumferential radiofrequency ablation of pulmonary vein ostia A new anatomic approach for curing atrial fibrillation. Circulation 2000 102(21 ) 261 9-2628. HohnloserSH, Kuck KH, LilienthalJ. Rhythm or rate control in atrial fibrillation—Pharmacological Intervention in Atrial Fibrillation (PIAF) a randomised trial. Lancet 2000 356(9244) 1789-1794. 

Frontrunner blunt microdissection catheter Radiofrequency ablation with optical Coherence reflectometry guidance Laser guidewire High frequency ultrasound... 

Rodriguez LM, Leunissen J, Hoekstra A et at. (1998) Transvenous cold mapping and cryoablation of the AV node in dogs observations of chronic lesions and comparison to those obtained using radiofrequency ablation. J Cardiovasc Electrophysiol 9 1055-1061... 

Flecainide slows conduction in all cardiac cells including the anomalous pathways responsible for the Wolff-Parkinson-White (WPW) syndrome. Together with encainide and moricizine, it underwent clinical trials to establish if suppression of asymptomatic premature beats with antiarrhythmic drugs would reduce the risk of death from arrhythmia after myocardial infarction. The study was terminated after preliminary analysis of 1727 patients revealed that mortality in the groups treated with flecainide or encainide was 7.7% compared with 3.0% in controls. The most likely explanation for the result was the induction of lethal ventricular arrhythmias possibly due to ischaemia by flecainide and encainide, i.e. a proarrhythmic effect. In the light of these findings the indications for flecainide are restricted to patients with no evidence of structural heart disease. The most common indication, indeed where it is the drug of choice, is atrioventricular re-entrant tachycardia, such as AV nodal tachycardia or in the tachycardias associated with the WPW syndrome or similar conditions with anomalous pathways. This should be as a prelude to definitive treatment with radiofrequency ablation. Flecainide may also be useful in patients with paroxysmal atrial fibrillation. 

Arruodarone is used in chronic ventricular arrhythmias in atrial fibrillation it both slows the ventricular response and may restore sinus rhythm it may be used to maintain sinus rhythm after cardioversion for atrial fibrillation or flutter. Amiodarone should no longer be used for the management of reentrant supraventricular tachycardias associated with the Wolff-Parkinson-White syndrome as radiofrequency ablation is preferable. 

It is doubtful whether this differs in its origins or sequelae from atrial fibrillation. The ventricular rate is usually faster (typically, half an atrial rate of 300, where 2 1 block is present), which is too fast to leave without treatment. Since, similarly, the patient is unlikely to have been in this rhythm for a prolonged period, there is less likelihood that atrial thrombus has accumulated. Conversion without prior anticoagulation may occasionally be considered safe but anticoagulation is usually also needed. Patients should not be left in chronic atrial flutter, and DC conversion will usually restore either sinus rhythm or result in atrial fibrillation. The latter is treated as above. Patients who fail to convert, or who revert to atrial flutter should be referred for consideration of radiofrequency ablation that is highly effective and may remove the cause of the atrial flutter > 80% of cases. 

The atrial rate is 120-250/min, and commonly there is AV block. If the patient is taking digoxin, it should be suspected as the possible cause of the arrhythmia, and stopped. If the patient is not taking digoxin, it may be used to control the ventricular rate. These patients should be considered for referral for radiofrequency ablation. 

This occurs in otherwise healthy individuals, who possess an anomalous (accessory) atrioventricular pathway they often experience attacks of paroxj mal AV re-entrant tachycardia or atrial fibrillation. Drugs that both suppress the initiating ectopic beats and delay conduction through the accessory pathway are used to prevent attacks e.g. flecainide, sotalol or amiodarone. Verapamil and digoxin may increase conduction through the anomalous pathway and should not be used. Electrical conversion may be needed to restore sinus rhythm when the ventricular rate is very rapid. Radiofrequency ablation of aberrant pathways will almost certainly provide a cure. 

Curley, S.A., Izzo, R, Delrio, R, Ellis, L.M., Granchi, X, Vallone, R, Fiore, F., Pignata, S., Daniele, B., Cremon, F. Radiofrequency ablation of unresectable primary and metastatic hepatic malignancies - Results in 123 patients. Ann. Surg. 1999 230 1-8... 

Iznmi, N., Asahlna, Y., Noguchi, O., Uchlhara, M., Kanazawa, N., Ita-kura, J., Himeno, Y., Miyake, S., Sakai, T., Enomoto, N. Risk factors for distant recurrence of hepatocellular carcinoma in the liver after complete coagulation by microwave or radiofrequency ablation. Cancer 2001 91 949-956... 

Livraghi, T., Goldberg, S.N., Lazzaroni, F., Meloni, F., Solbiati, L., Gazelle, G.S. Small hepatocellular carcinoma Treatment with radiofrequency ablation versus ethanol injection. Radiology 1999 210 655-661... 

Qf 136 patients with atrial fibrillation treated with either amiodarone (n = 96) or propafenone (n = 40), 15 developed subsequent persistent atrial flutter, nine of those taking amiodarone and six of those taking propafenone (58). In all cases radiofrequency ablation was effective. It is not clear to what extent these cases of atrial flutter were due to the drugs, although the frequency of atrial flutter in previous studies with propafenone has been similar. Atrial enlargement was significantly related to the occurrence of persistent atrial flutter in these patients. 

Natale A, Newby KH, Pisano E, Leonelli F, Fanelli R, Potenza D, Beheiry S, Tomassoni G. Prospective randomized comparison of antiarrhythmic therapy versus first-line radiofrequency ablation in patients with atrial flutter. J Am Coll Cardiol 2000 35(7) 1898-904. 

Schumacher B, Jung W, Lewalter T, Vahlhaus C, Wolpert C, Luderitz B. Radiofrequency ablation of atrial flutter due to administration of class IC antiarrhythmic drugs for atrial fibrillation. Am J Cardiol 1999 83(5) 710-13. 

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