Coexistence of type I atrial flutter and intra-atrial re-entrant tachycardia in patients with surgically corrected congenital heart disease
Joseph G. Akar, MDa,
Lai Chow Kok, MBBSa,
David E. Haines, MD, FACCa,
John P. DiMarco, MD, PhD, FACCa and
J. Paul Mounsey, PhD, BM BCh, FACCa
a Cardiovascular Division, Department of Internal Medicine, University of Virginia Hospital, Charlottesville, Virginia, USA
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Figure 1 Left anterior oblique view demonstrating catheter positioning during isthmus-dependent atrial flutter ablation. A Halo catheter is placed on the tricuspid annulus, and a quadripolar catheter in the right ventricle. A steerable quadripolar catheter is used for mapping and ablation along the tricuspid annulus/inferior vena cava isthmus. Abl = ablation catheter; Halo 1–2 = distal; Halo 19–20 = proximal; Quad = quadripolar catheter.
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Figure 2 Left anterior oblique view demonstrating catheter positioning during intra-atrial re-entrant tachycardia ablation. Catheters are positioned as in Figure 1, except for the ablation catheter, which is located along the lateral right atrial wall. Abbreviations as in Figure 1.
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Figure 3 (A) Typical isthmus-dependent atrial flutter (IDAF) in a patient with ToF (patient 12). The patient has had heart block since the surgical correction. Note the counterclockwise initial activation sequence in the Halo catheter positioned on the tricuspid annulus, with high-to-low activation of the lateral right atrial wall. Pacing performed through the distal ablation catheter (ABLATE-D) located near the ostium of the coronary sinus did not affect the activation sequence, and the postpacing interval was nearly identical to the tachycardia cycle length. HALO-1 = distal; HALO-10 = proximal. (B) Recording obtained during ablation of the isthmus between the tricuspid annulus and the inferior vena cava (IVC) in the same patient. The cycle length of the IDAF is prolonged in comparison with (A) as a result of partial ablation of the isthmus. The IDAF abruptly terminated during the RF energy application and was immediately replaced with an intra-atrial re-entrant tachycardia (IART) of different cycle length and activation sequence (arrows). This was an IART dependent on the region of the atriotomy scar in the lateral right atrium. Successful ablation of the tricuspid valve/IVC isthmus was confirmed after ablation of the IART. The surface electrocardiographic leads are I, L, F and V1.
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Figure 4 Example of scar-related intra-atrial re-entrant tachycardia (IART) from patient 11, who had undergone atrioventricular septal repair. There was a zone of slow conduction as evidenced by the fractionated potentials. There was also a line of conduction block (double potentials) causing the activation to proceed from Halo 4 down to Halo 10 and then back up to Halo 1. Pacing was performed in the lateral right atrium through the distal ablation catheter (ABLATE-D). A zone with low amplitude and fractionated potentials, suggestive of right atrial scar tissue, demonstrated acceleration of the tachycardia with concealed fusion. The postpacing interval was almost identical to the tachycardia cycle length. The surface electrocardiographic leads are I, L, F and V1. Intracardiac electrograms are as in Figure 3.
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Figure 5 Example of intra-atrial re-entrant tachycardia (IART) from patient 6, who had undergone the modified Fontan procedure for mitral atresia. The atrial remnant was too small to accept the Halo catheter, so right atrial activation was recorded using two decapolar catheters positioned on the atrial septum (RAA) and on the lateral right atrial wall (RAP). Pacing was performed through the distal ablation catheter (ABLATE-D). Mapping revealed early, low-amplitude, fractionated potentials on the low lateral right atrial wall. Pacing from this site demonstrated concealed entrainment with a postpacing interval close to the tachycardia cycle length. The surface electrocardiographic leads are I, L, F, and V1.
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