title: Atrial flutter ablation with a new radiofrequency catheter.
abstract: OBJECTIVE
  To assess the performance of a new radiofrequency catheter, specially designed for inferior vena cava-tricuspid annulus (IVC-TA) isthmus ablation, in the treatment of atrial flutter.
  
  
  METHODS
  IVC-TA isthmus ablation was performed in thirteen patients, eleven men and two women, aged 60 +/- 12, with a diagnosis of typical atrial flutter, symptomatic despite anti-arrhythmic therapy. The flutter was present for more than one year in seven patients and was paroxysmal in the remainder. The echocardiogram showed atrial enlargement in six patients. Atrial flutter was an isolated phenomenon in seven patients and in the remainder was associated with arterial hypertension (two patients), ischemic heart disease (two patients) and dilated cardiomyopathy (two patients).
  
  
  METHODS
  In the electrophysiologic study four diagnostic catheters were used, including one duodecapolar for mapping the tricuspid annulus. In the patients who presented with sinus rhythm, atrial flutter was induced with programmed atrial stimulation, and then the atrial activation circuit was mapped. To demonstrate the entrainment phenomenon the IVC-TA isthmus was over-stimulated, to prove that this was the slow zone of the circuit. The radiofrequency energy was applied in the IVC-TA isthmus with the Medtronic Cosio-Fluttr ablation catheter, for 60 sec per application, with temperature control and with a maximum energy output of 50 W. Criteria for success were not only the disappearance of the atrial flutter during the application of radiofrequency energy, but also the demonstration of bi-directional IVC-TA isthmus block.
  
  
  RESULTS
  The primary success rate was 100%. The mean procedure time was 110 +/- 22 min, mean fluoroscopy time was 23 +/- 4 min and the number of radiofrequency energy pulses was 9 +/- 3. There were no complications. The patients were followed for a mean time of 8 +/- 4 months and atrial flutter recurred in only one patient (8%).
  
  
  CONCLUSIONS
  Atrial flutter ablation with the new Medtronic Cosio-Fluttr catheter, specially designed for the application of radiofrequency at the IVC-TA isthmus, is a safe procedure and has a high success rate. It simplifies ablation, decreasing the number of radiofrequency energy pulses, without using long sheaths and keeping short procedure and fluoroscopy times.
authors.affiliation: Serviço de Cardiologia do Hospital de São Bernardo, Setúbal, Portugal.
authors.forename: J F
authors.initials: JF
authors.lastname: Santos
authors.forename: L
authors.initials: L
authors.lastname: Parreira
authors.forename: J
authors.initials: J
authors.lastname: Madeira
authors.forename: N
authors.initials: N
authors.lastname: Fonseca
authors.forename: R
authors.initials: R
authors.lastname: Buque
authors.forename: L
authors.initials: L
authors.lastname: Soares
authors.forename: L
authors.initials: L
authors.lastname: Inês
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000503:physiopathology / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation*; D004594:Electrophysiology; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged