The role of catheter ablation in atrial tachycardia, flutter, and fibrillation.

The first experiences of nonpharmacological treatment of ectopic atrial tachycardia (EAT), common atrial flutter (AFl), and atrial fibrillation (AF) were performed by surgical techniques. Many studies reported a very high success rate on the use of catheter ablation with radiofrequency current for the treatment of supraventricular arrhythmias; and recently, various preliminary reports are dedicated to the treatment of EAT, AFl, and AF with that source of energy. To our knowledge 108 cases of EAT treated by catheter ablation of the ectopic focus are reported in the literature with a success rate superior to 90%. On the basis of our personal experience regarding 11 cases (4 of right atrium EAT and 7 of left) we discuss here the essential role of unipolar leads derived from the mapping catheter to select the target for radiofrequency applications. Two hundred and one cases of AFl tested by catheter ablation were previously reported. The majority of them (> 80%) were successfully treated with radiofrequency. Some working groups performed the procedure as the basis of electrophysiological findings, while others preferred an anatomical approach applying radiofrequency energy at the isthmus lying between the coronary sinus ostium and the tricuspid ring, near the vena cava orifice. On the basis of these assumptions, we obtained 83% of final success in 12 cases of AFl treated by radiofrequency. Finally, we discuss the problem related to the modulation of atrioventricular (AV) nodal conduction during AF. In our laboratory, five cases with chronic AF and very fast ventricular response were treated with radiofrequency with a posterior septal approach. In all patients, we obtained very encouraging results with a constant decrease of ventricular rate (from 137 +/- 33 to 69 +/- 14 beats per minute). All cases treated by modulation of AV nodal conduction demonstrated an appropriate chronotropic response to the variations of the functional state that persists during the follow-up. More experience with longer follow-up and accurate pre- and postprocedure evaluations are needed to finalize the most appropriate technique of radiofrequency applications in these cases.

[New perspectives in the ablation of ectopic atrial tachycardia and atrial flutter]. / Nuove prospettive dell'ablazione nella tachicardia atriale ectopica e nel flutter atriale.

The first experiences on non-pharmacological treatment of ectopic atrial tachycardia (EAT) and common atrial flutter (AFl) were performed by surgical techniques. The surgical abolition of EAT comprised the isolation, the excision or the cryoablation of the ectopic atrial foci using electromapping guide. The AFl was treated by extensive cryoablation of the slow conduction area responsible for the macroreentrant process located in the infero-posterior part of the right atrium (RA). Transcatheter ablation with DC-shock for the treatment of EAT was proposed in 1985 but the technique did not gain wide acceptance due to its risks. The same method was utilized for the treatment of AFl since 1987. Many preliminary studies reported on the use of transcatheter ablation with radiofrequency (RF) current as an energy source since 1992 and no major complications were encountered. According with our knowledge, 81 cases of permanent or iterative EAT were treated by RF in the world with a primary success rate superior than 90%. The low rates of recurrence are reported very early (within 24-48 hours) after the procedure; recurrencies are very easy to recognise and they are successfully ablated in a second session. Cases of EAT due to an ectopic focus localized in the RA are ablated from the superior or inferior vena cava approaches and cases of EAT related to a left atrial (LA) ectopic focus by a trans-septal approach (persistent foramen ovale or atrial septum puncture). On the basis of our personal experience regarding 7 cases (4 LA and 3 RA foci) the role of unipolar leads derived from the mapping catheter appears essential to select the target for RF applications.(ABSTRACT TRUNCATED AT 250 WORDS)

[Indications and results of transcatheter ablation and surgery in paroxysmal reentry nodal tachycardia]. / Indicazioni e risultati dell'ablazione transcatetere e della chirurgia nelle tachicardie parossistiche da rientro "nodale".

In patients with nodal tachycardia refractory to medical therapy, transcatheter or surgical ablation is necessary. From January 1989 to December 1990, in 26/42 patients with nodal tachycardia, referred to our institution for electrophysiologic evaluation, transcatheter ablation by radiofrequency (20 patients) or surgical ablation by perinodal cryo (6 patients) was performed. In all these cases, a total refractoriness to several antiarrhythmic drugs alone or in association had been observed. The radiofrequency current, generated by the Osypka HAT 100 device, was administered through a tripolar USCI 7 F catheter. The ideal site for energy delivery was defined on the basis of a mapping, performed in the A-V junction area. In order to find out the most premature retrograde atrial activation, the following areas were explored: right bundle, atrial His bundle, peri-nodal region, proximal His bundle and coronary sinus ostium. Local atrial activation time was evaluated during nodal tachycardia by delivering a premature ventricular extrastimulus to discover the atrial deflection from the ventricular one. In the selected area, 5 applications (range 1-12) of 20-25 W power radiofrequency energy for 5-30 s were delivered on average. A complete prevention of nodal tachycardia was achieved in 18/20 patients (90%). Only in 2 patients a total A-V block was induced. The pre- and post-procedure values are as follows: AH: pre 71 +/- 19, post 113.6 +/- 50; HV: pre 45.5 +/- 8, post 47 +/- 6; aWP: pre 353 +/- 57, post 391 +/- 87; rWP: pre 322 +/- 58, post 411 +/- 58. In 10/18 cases the AH interval was normal after radiofrequency application.(ABSTRACT TRUNCATED AT 250 WORDS)

[Coronary angiographic findings in the myocardial infarction involving the dorsal wall of the heart (author's transl)]. / Rilievi coronarografici nell'infarto miocardico con estensione alla parete dorsale del cuore

The Authors report the results of a coronary angiographic study in 12 patients with acute myocardial infarction in which the necrosis was extended to the dorsal wall of the heart. The electrocardiographic and vectorcardiographic criteria applied in order to assess the involvement of the dorsal wall have been those suggested by Perloff and by Hoffman and coll. and Massie and Walsh, respectively. The diagnosis of dorsal involvement has been also confirmed by the esophageal electrocardiogram. Discussing their results, the Authors consider the variants of blood supply of the posterior wall of the heart. On the basis of their angiographic findings, they underline that significant lesions of the circumflex artery, either alone or associated with narrowing of other main coronary arteries, are the most frequent finding in cases of myocardial infarction involving the dorsal wall of the heart.