Diamond-AF Clinical Trial

Comparing the DiamondTemp™ ablation system versus a contact force-sensing ablation system (CF-RF).

Study Background and Design


Tissue temperature is a well-established biophysical parameter of irreversible tissue damage. Irrigated RF was introduced to mitigate the risk of char and thrombus formation; however, thermal acuity is disrupted.

To address these limitations, the DiamondTemp ablation system (DTA) was designed to accurately measure tip-tissue temperature during energy delivery.


The DIAMOND-AF trial was an FDA-regulated, prospective, multicenter, non-inferiority, randomized, controlled trial which compared safety and effectiveness of DTA and a contact force-sensing ablation system (TactiCath™) (Control).

482 paroxysmal AF patients were randomized (239 DTA and 243 control) for PVI at 23 sites in the United States, Europe, and Canada. Patients were followed for 12 months.

Key Findings

Primary Safety and Efficacy Endpoint Achieved

DTA demonstrated comparable efficacy and both cohorts required very few repeat procedures. Safety and efficacy of the DTA system proved non-inferior to contact force-sensing RF ablation for the treatment of patients with paroxysmal AF. 

Primary Safety Endpoint Met 3.3%

Safety event rate compared with 6.6% with contact force-sensing RF.

Primary Effectiveness Endpoint Met 79.1%

Compared with 75.7% with contact force-sensing RF.

Graphic showing DiamondTemp has a 79.8% 12-month Kaplan-Meier estimate freedom from primary effectiveness endpoint

Efficiency Data Versus CF-RF

The DTA system demonstrated procedural efficiencies compared to CF-RF.1

  • 40% reduction in RF time
  • 55% reduction in individual RF ablation duration
  • 58% reduction in saline infusion

Metric DTA Group Control Group % Reduction with DTA*
Total RF Time 17.9 ± 8.1 min  29.8 ± 14 min 39.9%
Individual RF ablation duration 14.7 ± 5.3 s 32.6 ± –25.3 s 54.9%
Saline infusion volume 332.2 ± 120.8 ml 785.5 ± –351.5 ml 57.7%

*Calculation based on manuscript values.



The primary effectiveness endpoint was freedom from recurrence of an atrial arrhythmia (AF, AFL, AT) during the effectiveness period. This was a composite endpoint of seven (7) failure criteria.


The primary safety endpoint is defined as freedom from a composite of serious adverse events (SAE) occurring within 30 days and clinically symptomatic pulmonary vein stenosis through 6 months post-index ablation procedure. 

Primary Effectiveness Endpoint
Freedom from recurrence of atrial arrhythmias (AF/AFL/AT)

Feedom from recurrence of atrial arrhythmias (AF/AFL/AT) chart from the Diamond-AF trial

1. Blanking period

Effectiveness Failure Criteria

  • Inability to isolate all PVs
  • Use of a non-study device
  • > 1 repeat procedure

2. Effectiveness Period

Effectiveness Failure Criteria

  • Documented ≥ 30 sec of AF/AFL/AT
  • New or modification to pre-existing Class I-IV AAD
  • DCCV
  • Repeat procedure

Study Population

Key Inclusion Criteria

  • Symptomatic paroxysmal AF
    • At least two self-terminating AF episodes reported in last 6 months
    • At least one ECG documented episode in last 12 months
  • Prior Class I-IV AAD failure
  • ≥ 18 years of age

Key Exclusion Criteria

  • Prior cardiac interventions
  • Neurological events within 6 months
  • Class III/IV or uncontrolled heart failure
  • Left ventricular ejection fraction < 35%
  • Left atrial diameter > 5.5 cm

Additional Resources

*Calculation based on manuscript values.



Kautzner J, Albenque JP, Natale A, et al. A Novel Temperature-Controlled Radiofrequency Catheter Ablation System Used to Treat Patients With Paroxysmal Atrial Fibrillation. JACC Clin Electrophysiol. Published online January 27, 2021.