Left atrial flutter induced by catheter ablation

SAN DIEGO, CALIFORNIA. The three most commonly used procedures for isolation of aberrant electrical impulses originating in the pulmonary veins are:

  • Segmental pulmonary vein isolation (SPVI or Haissaguerre procedure) In this procedure electrophysiological mapping (using a multipolar Lasso catheter) is used to locate the pathways taken by aberrant impulses from the pulmonary veins and these pathways are then eliminated by ablation around the veins approximately 5 to 10 mm from the ostium of the veins.

  • Circumferential anatomical pulmonary vein isolation (CAPVI or Pappone procedure) In this procedure anatomical mapping (CARTO) is used to establish the exact location of the pulmonary veins. Two rings of lesions are then created in the left atrium - one completely encircling the left pulmonary veins and another completely encircling the right pulmonary veins; the two rings are usually joined by a linear lesion.

  • Pulmonary vein antrum isolation (PVAI or Natale procedure) This procedure is a variant of the Haissaguerre procedure. It involves locating aberrant pathways through electrophysiological mapping (using a multipolar Lasso catheter) and ablating these pathways guided by an ultrasound (ICE) catheter. The ablation is performed as close as possible to the outside edge (antrum) of the junction between the pulmonary veins and the atrial wall. All four pulmonary veins as well as the superior vena cava (if indicated) are isolated during the procedure.

  • All three variants of the PVI procedure may be followed by focal ablations involving other areas of the atrium wall or creation of linear lesions in order to isolate sources of afib located outside the pulmonary veins.

There is growing concern that the use of linear ablations may have unintended effects, in particular, the creation of iatrogenic (procedure-caused) arrhythmias such as left atrial flutter. Electrophysiologists at the University of California Medical School now confirm that linear ablation is indeed associated with an increased risk of post-procedural left atrial flutter. Their clinical trial included 66 consecutive patients with paroxysmal lone AF (73% male, average age of 57 years and average duration of AF of 5.6 years). The patients were randomized to receive a segmental PVI including a right atrial flutter ablation or a circumferential, anatomically guided PVI with a lesion line (roof line) connecting the left and right rings encircling the pulmonary veins as well as a mitral isthmus line connecting the mitral valve annulus with the left encircling ring. Total fluoroscopy time (radiation exposure) was 73 minutes in the segmental group vs. 91 minutes in the circumferential group.

All patients were followed up at 1, 3, 6, 12 and 24 months following the ablation and every 12 months thereafter. Before the 6- and 12-month follow-up visits, patients were continually monitored for 2 weeks to spot any arrhythmia occurrence. Sixteen months after the initial procedure 58% of patients in the segmental group were free of all atrial arrhythmias and off all antiarrhythmic drugs. The corresponding number for the circumferential group was 52%. Thirty percent of patients in the segmental group underwent a repeat PVI after which 85% remained in normal sinus rhythm without the use of antiarrhythmics. In the circumferential group, 40% underwent a repeat procedure after which 85% remained free of AF without the use of antiarrhythmics.

Following the initial procedure, paroxysmal AF recurred in 14 patients in the segmental group and in 8 patients in the circumferential group. However, another 6 patients in the circumferential group developed left atrial flutter and 2 developed both left atrial flutter and experienced recurrence of paroxysmal AF as well. Six patients underwent a follow-up ablation for left atrial flutter of which 5 were immediately successful and one required a repeat procedure. Three complications occurred among the 66 patients (4.5%) 1 femoral hematoma, 1 femoral pseudoaneurysm, and 1 pericardial effusion with tamponade, all of which were successfully resolved. The researchers conclude that linear lesions, in particular the mitral isthmus line, are associated with a greater incidence of left atrial flutter, should be avoided whenever possible, and should not be used in the initial ablation of patients with paroxysmal AF and structurally sound hearts.
Sawhney, N, et al. Circumferential pulmonary vein ablation with additional linear ablation results in an increased incidence of left atrial flutter compared with segmental pulmonary vein isolation as an initial approach to ablation of paroxysmal atrial fibrillation. Circulation: Arrhythmia and Electrophysiology, Vol. 3, June 2010, pp. 243-48