Atrial flutter ablation with a new radiofrequency catheter

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.

PATIENTS

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.

[Deciding about pacing mode in sinus node dysfunction: should carotid sinus massage be performed and in which circumstances?]

OBJECTIVE

To state the incidence of carotid sinus syndrome (CSS) with atrioventricular node manifestation in patients with sinus node dysfunction (SND) and indication for a definitive pacemaker (PM), we propose a new protocol between atrial pacing AAI and double chamber DDD.

POPULATION AND METHODS

69 patients (PTS) (male 71%), median age 65 +/- 10 years, with SND (normal PQ and no intraventricular conduction defect), that had a PM implant following the protocol that included carotid sinus massage for the pacing decision, were followed prospectively between December 1995 and November 1999. During the protocol we implanted DDD PM in PTS with Wenckebach less than 130 or Wenckebach equal/over 130 and CSS. At least, in PTS with Wenckebach equal/over 130 and no CSS we implanted AAI PM. The follow-up was between 4 months and 4 years, with clinical evaluation in the first and fourth months and then half yearly, with carotid sinus massage in the first evaluation.

RESULTS

About 1/4 of the 69 patients followed had SND without carotid sinus syndrome, or atrioventricular node repercussion; the SND involved the atrioventricular node in 56% of the patients, and there was a relation between the SND and carotid sinus syndrome in 18.8%. The follow-up revealed, in all patients, a complete remission of the symptoms, and when we repeated the carotid sinus massage in the first evaluation, there was a response like in the surgery room, in all patients.

CONCLUSIONS

There is a significant number of patients with SND and carotid sinus syndrome. The carotid sinus massage performed in the surgery room does not influence the test sensitivity and specificity in the diagnosis of carotid sinus syndrome. The authors think that carotid sinus massage should be considered in the protocol that defines the pacing mode, in patients with SND, and that influence the choice of pacemaker in 18.8% of patients.