Contact-Force-Sensing-Based Radiofrequency Catheter Ablation in Paroxysmal
Supraventricular Tachycardias: a randomized controlled trial

There is compelling evidence that contact force (CF) between the tip of the
catheter and the target tissue within the cardiac chamber is a key factor to
safe and effective lesion creation during radiofrequency ablation of cardiac
arrhythmias. Insufficient CF leads to ineffective lesion formation, whereas
excessive CF may result in procedural complications such as myocardial
perforation, steam pops, thrombus formation, or esophageal injury and phrenic
nerve palsy.Since the introduction of CF-sensing into catheter ablation therapy
many studies have demonstrated the importance of this novel technology in the
field of atrial fibrillation ablation. A lower recurrence rate and shorter
procedure, ablation and fluoroscopy times have been reported with CF-sensing,
in comparison with conventional therapy. In addition, these studies also
suggest that CF sensing might enhance safety of ablation procedures by helping
to avoid mechanical injury due to excessive contact, thereby reducing the
chance for cardiac perforation3,4,6-18,20,22. Moreover, based on the findings
of these clinical trials important CF- parameters have been determined and
introduced into clinical practice guidelines for atrial fibrillation ablation,
such as: minimum CF, target CF, minimum force-time-integral (FTI) continuity
index (CI) and lesion-size index (LSI)3,11,17. These parameters help
electrophysiologists to standardize their procedure and achieve lower
recurrence and complication rates in atrial fibrillation ablation.
Although the usefulness of CF-technology seems obvious in the field of atrial
fibrillation ablation, due to a number of reasons, there have been little
attention focusing on the importance of CF-sensing in the ablation process of
paroxysmal supraventricular tachycardia (PSVT). This is the first randomized
controlled study that aims to assess the usefulness of CF-sensing in PSVT
ablation. We hypothesize that CF-sensing can further improve procedural
outcomes and contribute to the increase of acute and long-term success rates
and the decrease of procedural risks.

The primary objective of the present study is to demonstrate the superiority of
contact-force-sensing in the ablation of AVNRT and WPW-AVRT as assessed by the
improvement in the number and duration of radiofrequency applications compared
with the conventional ablation approach.
Secondary objectives of the study are the followings:
1, to demonstrate that contact-force-sensing catheters are superior in terms of
total procedure duration and fluoroscopy times in the case of PSVT ablation.
2, to show that the use of contact-force sensing catheters is non-inferior to
conventional catheters (without contact-force-sensing) in terms of
acute/long-term procedural success and procedural safety (major/minor
complication rate) of PSVT ablations.

COBRA-PATH is a prospective open multicenter randomized controlled trial, which
will be conducted in several tertiary electrophysiology (EP) centers with
experience in PSVT ablation. The duration of the inclusion period is expected
to be maximum 12 months and the follow-up period will comprise 12 months.
Eligible patients referred to EP centers due to PSVT (i.e. atrioventricular
nodal reentrant tachycardia and atrioventricular reentrant tachycardia with
manifest or concealed accessory pathways) will be enrolled after obtaining
informed consent, and randomized in a 1:1 fashion to undergo PSVT ablation
using either conventional (non-contact-force-sensing) ablation catheters
(control group) or contact-force-sensing catheters (CF group). Data regarding
procedural aspects (application number of radiofrequency ablation, total
procedural time, ablation time, radiation exposure) and outcome measures (acute
success rate, recurrence rate, safety risk) will be collected and analyzed, in
order to assess the potential benefit of CF-sensing over conventional ablation
procedure.

The diagnostic part of the procedure will be implemented according to the
standards of a basic electrophysiology (EP) study for PSVT. After the
diagnosis of AVNRT or WPW-AVRT have been confirmed the patients will be
randomly assigned to one of the treatment arms. Depending on the results of
this randomization procedure the ablations will be performed using either a
conventional (non-irrigated, non-CF-sensing) ablation catheter (control group)
or the TactiCathTM Quartz open-irrigated (six holes) contact-force-sensing
catheter (CF-sensing group).

We expect that adding contact-force-sensing technology to the conventional
ablation approach can further improve acute and long-term success rates of
AVNRT/WPW-AVRT ablations, and might also further improve the safety profile of
these procedures. In terms of basic procedural parameters (RF application
number/time, total procedural time, fluoroscopy time) we definitely expect an
improvement compared with the conventional technology. Our expectations are
based on the results of several clinical trials which demonstrated that
CF-sensing improves clinical outcomes in patients with atrial fibrillation in
comparison with conventional catheter-based therapy. Since catheters equipped
with CF-sensing technology already have an established role in atrial
fibrillation ablation, and are also demonstrated to represent a safe
methodology, we raise no potential concerns regarding the usage of the same
types of catheters in the population of patients with PSVT. On the contrary, we
strongly believe that the above mentioned results of the CF-sensing technology
in atrial fibrillation are also highly suggestive for the fact that this
technology will be also beneficial for PSVT patients, however clear evidence
(based on randomized controlled clinical trials|) showing the superiority of
this technology in this patient population is still lacking.