br Case report A year old man with
Case report A 54-year-old man with a surgically repaired DORV was admitted to our hospital due to palpitations and worsened right ventricular heart failure. He had been diagnosed with DORV and had undergone the Blalock Taussig operation at 7 years of age. He underwent the Rastelli operation at 35 years of age, with a repeat Rastelli operation at 42 years of age. A 12-lead ECG on this admission showed AT with an atrial nitric oxide inhibitor length (CL) of 300ms, and an inverted saw-tooth F wave pattern was identified in the inferior leads II, III, and aVF, typical of atrial flutter. His chest X-ray showed cardiomegaly with a cardiothoracic ratio of 61% and mild pulmonary congestion. Transthoracic echocardiography confirmed severe right atrial (RA) and ventricular dilatation. Continuous-wave Doppler examination from the left apical 4-chamber view identified marked tricuspid insufficiency with a systolic pressure gradient across the tricuspid valve of 40mmHg. After written informed consent was obtained, an electrophysiological study was performed absent antiarrhythmic agents. Electrode catheters were inserted percutaneously and positioned at the His bundle region and coronary sinus. A 20-pole electrode was placed along the tricuspid annulus (TA). An 8F 4-mm–tip radiofrequency electroanatomical mapping/ablation catheter (Navistar, Biosense Webster, Inc.) was used for mapping and ablation. Surface and intracardiac electrocardiograms from catheters were amplified, filtered (30–500Hz), monitored, recorded, and analyzed using Bard Electrophysiology equipment (BARD, Inc.). Electrical stimulation was performed using BC02, a digital stimulator (Fukuda. Denshi, Inc.). Three-dimensional activation sequence mapping was performed during ATs with a CARTO3 mapping system (Biosense Webster, Inc.). The 3D geometry of the right atrium was reconstructed in real time with the electrophysiologic data, which was colored and superimposed on an anatomic map. Mapping was completed when a sufficient number of points to account for 90% of the tachycardia cycle length (TCL) had been acquired to determine the circuit during the AT . The area without recordable activity or a bipolar voltage amplitude of <0.05mV was identified as scar and appeared gray on the 3D activation map. Low-voltage regions were defined by the presence of a bipolar voltage of <0.5mV, as reported elsewhere [9–11]. The regions around the low-voltage area and scar were mapped carefully to delineate the border between 2 areas. Automatically assigned activation times were manually verified and corrected when necessary, and a single activation time was contextually assigned for fractionated and double-spiked potentials on the basis of simultaneous tip unipolar signals and surrounding activation. The 3D voltage map, performed during AT, is shown in Fig. 1(a). It shows a vertical line with double potential on the RA free wall in the RAO projection, suggesting an incisional line. In the right posterior oblique projection, a large low-voltage area is shown on the RA posterolateral wall, appearing to involve the lesions from cannulation of the superior vena cava (SVC) and inferior vena cava (IVC). In the middle of the low-voltage area, there was a vertical line with double potential and fractionated potential. The operative records showed that the incisional line was positioned on the RA free wall and SVC and IVC cannulas of were inserted into the RA. Our estimated incisional line and the lesions of cannulation coincided with the sites described in the operative report. AT1 (Fig. 1b(A)) was observed on initiation of the procedure. The intracardiac electrogram during AT1 is shown in Fig. 2(a). The earliest atrial activation was observed in the lower anterior RA. The atrial activation propagated in the distal direction to the cavotricuspid isthmus (CTI) and in the proximal direction along the incisional line. It was easier to understand this propagation on the CARTO3 map. Fig. 2(b) shows the activation in front of and behind the incisional line. On the CARTO3 map, which shows the position of the catheters and the anatomical construction accurately, it is possible to interpret this activation going up in front of the incision and down behind the incision. The 3D activation map suggested that the wavefront propagated counter-clockwise around the incisional line. In addition to that, in the entrainment pacing of the tachycardia, the post pacing interval (PPI) from the 3 sites around the incisional line was identical to the TCL. AT1 was identified as a macroreentrant tachycardia circling around an incisional line, and an ablation line was made between the bottom of the incision and the IVC. AT1 was terminated.