The RhythmiaTM 3-dimensional (3D) mapping system coupled with a new nonfluoroscopic approach that reduces exposure to radiation was found to be safe, effective, and well tolerated during arrhythmia ablation procedures, according to a study published in the Journal of Electrocardiology.

Both patients and clinicians are exposed to substantial radiation during conventional electrophysiology (EP) studies and subsequent ablation procedures that are conducted under fluoroscopic guidance. The use of nonfluoroscopic 3-D mapping has offered physicians reduced radiation exposure (“near-zero fluoroscopy”), in addition to improved catheter tracking thanks to the use of a new navigation-enabled catheter.

The Rhythmia mapping system is a proprietary technology in which a pair of novel ablation catheters are used for procedures involving atrial flutter (IntellaNavTM MiFi XP catheter), atrioventricular (AV) reentrant tachycardia (AVRT), or AV nodal reentrant tachycardia (AVNRT; IntellaNav ST catheter). The procedure consists of 4 phases: patient preparation (electrode and back patch placement); anatomy and field map creation (threading of IntellaNavTM from the femoral vein to the right atrium and reconstruction of anatomical geometry); diagnostic catheter placement (insertion and advancement of decapolar and 4-pole catheters); and performance of retrograde EP study (induction of the tachyarrhythmia and ablation via the slow pathway).

A total of 20 consecutive patients (mean age, 58 years; 48% men; 14 patients with AVNRT, 4 with AVRT, and 2 with atrial flutter) referred to a single center for radiofrequency (RF) ablation were enrolled between November and December 2018 and divided into 2 groups. Ten participants (group 1) received standard ablation using the Rhythmia system but under typical fluoroscopic guidance (reference conventional group), and 10 patients (group 2) were treated with a near-zero ray-guided nonfluoroscopic approach using the RhythmiaTM system and associated IntellaNav catheters (experimental group). In group 2, fluoroscopy was used only when necessary.

In group 2, 80% of the procedures were completed without fluoroscopy (compared with 0% in group 1; P =.0007). Mean mapping times were longer in group 2 vs group 1 (703 seconds vs 317 seconds, respectively; P =.0001). There were no significant between-group differences in the number of RF applications (5±2 vs 4.4±2 in groups 1 and 2, respectively; P =.548) or in the total time for RF procedure (191 vs 198 seconds in groups 1 and 2, respectively; P =.8475). Participants in group 2 vs group 1 had lower radiation exposure (0.6 vs 32 mGy, respectively; P =.0004) and shorter radiation exposure times (12 vs 158 seconds, respectively; P =.0005).

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All procedures were successful, regardless of treatment group. No complications were reported, and no patients experienced a recurrence of their arrhythmia following ablation through 6 months of follow-up.

Study limitations include a small sample size and single-center design.

“In our preliminary experience, arrhythmia ablation through a near-zero fluoroscopy approach involving the use of a novel ablation technology and the Rhythmia™ mapping system proved to be safe, feasible and effective in common atrial arrhythmias,” noted the authors. They recommended that future research involve prospective clinical trials with larger patient populations and more diverse operators at multiple centers.


Cauti FM, Rossi P, Iaia L, Bianchi S. A new mapping method with the Rhythmia™ navigation system reduces radiation exposure. Preliminary experience in SVT procedures. J Electrocardiol. 2019;58:92-95. doi:10.1016/j.jelectrocard.2019.11.049