Macroreentrant form of an adenosine 5′-triphosphate–sensitive atrial tachycardia arising from the vicinity of the atrioventricular node involving the tricuspid and mitral annuli as its reentrant circuit

Figure 1. A: Intracardiac recording of the termination of the tachycardia without atrioventricular block after a bolus injection of adenosine 5′-triphosphate. B: P-wave morphologies during the tachycardia. The P wave (arrow) just after cessation of ventricular pacing was negative in the inferior and V3–6 leads, biphasic (negative/positive) in I and V1–2, and positive in aVL. C: Activation maps during the tachycardia (left anterior oblique-cranial view). The pink tags (sites A, B, C, and D) show the pacing sites during the tachycardia. The yellow tags show the points where the His potentials were recorded. The green tags (RF1–RF3) show the radiofrequency catheter ablation sites. D: Entrainment mapping during the tachycardia. The pink and golden yellow tags show the pacing sites where orthodromic capture was observed. The blue tags show the sites where antidromic capture was observed. CS = coronary sinus; HBE = His-bundle electrode; HRA = high right atrium; RF = radiofrequency; RVA = right ventricular apex.

Figure 2. Intracardiac recordings during entrainment pacing during the tachycardia, with pacing from A: the right atrial anterior septum, B: anterior tricuspid annulus, C: noncoronary cusp, and D: mitral annulus. Each pacing site is shown in Figure 1C. The red arrows show the orthodromic atrial activation and the blue arrows show the antidromic atrial activation. The P-wave morphology of the last paced beat (red arrowhead) is similar to the tachycardia (red star). Magnified P wave shown in the square box. An = atrial beat paced by Sn pacing; MAP = mapping catheter, S = stimulation. The other abbreviations are as in Figure 1.

Figure 3. A, B: Entrainment pacing, C: successful catheter ablation, and D: schematic presentation. A: Entrainment pacing and number of pacing stimuli needed to entrain (NNE) for measurements at a site on the anterior tricuspid annulus (TA) near site RF1 (shown in the upper right panel of part D). The cycle length at the HRA and CS accelerated to the pacing cycle length (red asterisks) and the NNE count was 3. B: Entrainment pacing and the NNE measurement number at a septal mitral annulus (MA) site around site RF2 (shown in the lower right panel of Figure 3D). The cycle length at the HRA and CS accelerated to the pacing cycle length (red asterisks) and the NNE count was 2. C: Intracardiac recordings of the successful catheter ablation from the NCC. Ablation at the RF3 site (shown in the lower left panel of part D) terminated the tachycardia. D: Schematic presentation of entrainment pacing during the tachycardia. The abbreviations are as in the previous figures.