Catheter ablation of atrial tachycardia originated from the ostium of anomalous drainage between left interior pulmonary vein and left atrial appendage
Atrial tachycardia (AT) from the left atrium are well recognized. In most cases, such arrhythmias usually occur in patients without structural heart disease; the common origin was identified at mitral annulus, left atrial appendage (LAA) and pulmonary vein (PV)1,2. However, there is no report about AT in patient with anomalous pulmonary venous drainage. We report one case with focal AT originating from the ostium of anomalous drainage between left interior PV (LIPV) and LAA.
Case report
An 18-year-old man with paroxysmal AT for six months was referred to our center for catheter ablation. The echocardiogram did not suggest any evidence of malformation or structural heart disease and showed a normal
left ventricular ejection fraction. The 24-Holter monitoring reveal high burden of AT (84.6%) with prolonged sinus pauses (5.38sec) following the self-termination of AT. The P wave of 12-lead electrocardiogram (ECG) during the AT is shown in Figure 1B . This patient’s imaging was obtained by multidetector computed tomography, and using retrospective electrocardiographic gating (Somatom Definition and Force, Siemens Medical System, Germany), the axial CT imaging show the anomalous drainage between LIPV and LAA, and the dilatation of distal LIPV and the stenosis of proximal LIPV were also observed (Figure 1A ).
The electrophysiology study was performed in the fasting state under conscious sedation with administration of intravenous fentanyl. The coronary sinus (CS) activation sequence demonstrated the AT originated from left atrium (LA) using a 6F decapolar catheter (Diag, St. Jude Medical Inc., St. Paul, MN, USA); After transseptal puncture, intravenous heparin was administered to maintain an activated clotting time of 250 to 350 seconds, an irrigated catheter (Navi-star, Biosense Webster) was inserted into the LA for mapping and ablation using a CARTO system. An activation map of the LA revealed that the site of earlier activity during tachycardia was broad at the LAA ridge and LIPV inferior ostium; however, the activation time at proximal ABL catheter was earlier than the distal ABL catheter. We drag back the ABL catheter to site of ABL34 and mapped the earliest activity with low contact force (3g, Figure 1C ). The target activation preceded P wave by 39ms (Figure 2, left panel ), the AT elimination was achieved by ablation at the site of earliest activity after 4 sec (Figure 2, right panel ). Further inducibility testing with programed stimulation and burst pacing from the CS was unable to induce any atrial arrhythmia after successful ablation. The restructure of LA geometry showed the anomalous drainage between the LIVP and LAA using CARTO system after the ablation procedure (Figure 3A ). CARTO merge showed the ABL catheter was located at edge of anomalous drainage between the LIVP and LAA (Figure 3B ). During six months follow-up, the patient had no recurrence, regular 24-Holter monitoring did not showed any sinus pauses.