A 43-year-old male with recurrent symptomatic AVRT and previously failed attempts of CA underwent repeated CA using DCDM. The patient was referred to our department for an EP study with recurrent symptomatic narrow QRS complex tachycardia (). His resting ECG showed ventricular pre-excitation (). During the CA procedure orthodromic AVRT using a left-anterolateral AP developed with catheter manipulation. Radiofrequency (RF) CA at the earliest retrograde atrial signal changed the retrograde activation pattern, without major change in the cycle length (), while coronary sinus catheter maintained stable position. Ablation at the posterolateral mitral annulus resulted in termination of tachycardia and disappearance of pre-excitation (). After early arrhythmia recurrence, a second CA attempt was performed, 6 months after the first procedure, unsuccessfully. Considering two failing attempts using conventional EP tools, the patient was scheduled for repeat CA using the DCDM system (AcQMap, Acutus Medical, Carlsbad, CA, USA). The DCDM mapping system is a non-contact high-resolution charge density-based mapping technology that allows visualization of global atrial activation by combining highly accurate ultrasound-based 3D endocardial anatomy reconstruction with high-resolution propagation maps of electrical activation. The system is using an invasive diagnostic recording basket catheter (AcQMap catheter, Acutus Inc., 10F), which incorporates 48 biopotential electrodes and 48 ultrasound transducers. The real-time anatomy is rapidly created within 1.5–3 min based on point sets (115.000 surface points/minute) and corresponds to the end-diastolic shape and size. Activation maps are created within 2 min by measuring the non-contact unipolar voltage field (150.000 intra-cardiac unipolar voltages/second) to calculate cardiac activation as charge density and are displayed across the reconstructed 3D anatomy with a spatial resolution of 1 mm. The non-contact module of the DCDM system consists of two mapping modalities: single-position mapping and SuperMap. Single-position maps can be applied to assess global simultaneous cardiac activation in the chamber of interest using a single atrial beat, while SuperMap allows non-contact measurements by aligning different beats acquired at different locations and at different times. The mapping basket catheter was advanced into the left atrium via intra-cardiac echocardiography guided trans-septal approach. Left atrial anatomy was built using non-contact ultrasound mapping. Next, single-position activation and super-map were performed during AVRT (similar ECG pattern and cycle length as first two CAs) using DCDM. The DCDM propagation maps identified two quasi-simultaneous early atrial activation sites at the left-lateral and left-anterolateral atrial aspects of the mitral annulus, consistent with the possibility of single AP with dual atrial insertion sites (). A Kent potential was not identified. Using remote magnetic navigation (MagnoFlush, Medfact, Germany; 45W), RF was applied at the left lateral mitral annulus targeting the earliest atrial activation fused with the ventricular electrogram (), resulting in termination of tachycardia ( and ). A new single-position DCDM activation map was performed during right ventricular pacing showing septal earliest atrial activation, resembling retrograde conduction using the atrioventricular node () thus suggesting successful ablation of the mid-body of the AP. After 20-min waiting period, no AP conduction could be seen at adenosine test, and with isoproterenol challenge, tachycardia was non-inducible. Total procedure time was 128 min and fluoroscopy time 15.5 min. At 3-month follow-up, the patient was arrhythmia free, without pre-excitation on surface ECG and reported significantly improved quality of life.