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5 Facts ABOUT WHY Temperature Matters

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Temperature Matters because surgical ablation procedures rely on specific temperatures to induce irreversible cell death. Delivery of too much RF energy may overheat and char tissue; and temperatures that aren’t cold enough may not completely freeze tissue.

Medtronic is committed to cardiac surgery and providing you with technologically advanced surgical ablation devices, designed with temperature control and ease of use in mind.


1. For Cryoablation COLDER MATTERS

The Cox maze IV procedure using an argon-based cryoprobe was safe and effective compared with the maze procedure using an N2O-based cryoprobe in terms of operative outcomes and the restoration of sinus rhythm for up to 2 years after surgery.1
Graph on the effects of cryo on tissue


Surgical ablation systems powered by argon gas freeze tissues to temperatures colder than -40° C in under two minutes in 4, 6, and 8 mm tissue thicknesses.
chart on why lethal gas choice matter for ablation

3. For Radiofrequency ablation CONTROLLED HEAT MATTERS

Only the Cardioblate™ irrigated RF surgical ablation system has irrigation and automatic power adjustments to maintain temperatures in the effective heating ranges enabling transmural lesions.

The optimal transmural lesion is created in tissue temperatures of 50⁰–100⁰ C.
Chart on the effect of heat on tissue


Heating tissue above 100⁰ C may produce microbubbles and char, which are barriers to energy flow, and inhibits lesion creation.10,11

Irrigated RF cools the surface temperature of tissue and increases RF energy delivery, reducing the likelihood of charring.9,12,13 Irrigated bipolar radiofrequency ablation with impedance monitoring safely and reliably produces electrically isolating, transmural Cox maze lesions in vivo.14
Graph on the importance of irrigation for radiofrequency ablation


A dose response algorithm is embedded into the software that powers Cardioblate™ technology. This algorithm was designed to adjust the power output of the devices based on changes in tissue impedance during an ablation, allowing for maximum power delivery.
Impedance and power work together:
  • An increase in impedance decreases power
  • An impedance plateau increases power
Graph on the importance of algorithm for radiofrequency ablation


Cardioblate™ BP2 Irrigated RF Surgical Ablation Device

Image of a Cardioblate BP2 surgical ablation device


  • flexible, malleable electrodes can be rotated through 300° and conformed to address even the most challenging anatomies
  • the malleable 7cm active electrodes facilitate placement
  • flexible neck provides clear line of sight and optimal positioning

Cardioblate Cryoflex™ Surgical Ablation probes

Image of a Cardioblate Cryoflex surgical ablation device


  • distinctly malleable, allow for ease shaping by hand to address varying anatomies
  • available in 7 cm and 10 cm lengths
  • ablation length of the probe tip can be adjusted, helping to shield non-targeted tissue



Kyung-Hak Lee, M.D. et al: Efficacy of Cox Maze IV Procedure Using Argon-Based Cryoablation: A Comparative Study with N2O-Based Cryoablation, Korean J Thorac Cardiovasc Surg 2014;47:367-372


Gage AA, Baust JM, Baust JG. Experimental cryosurgery investigations in vivo. Cryobiology. December 2009;59(3):229-243


Baust JG, Gage AA. Progress toward optimization of cryosurgery. Technol Cancer Res Treat. April 2004;3(2):95-101.


Baust JG, Baust JM. Advances in Biopreservation. Boca Raton, Fla: CRC Press; 2007:90-93.


Gage AA, Baust J. Mechanisms of tissue injury in cryosurgery. Cryobiology. November 1998;37(3):171-186.


Seo CH, Stephens D, Cannata J, et al. Monitoring radiofrequency catheter ablation using thermal strain imaging. Presented at IEEE International Ultrasonics Symposium 2010; San Diego, CA.


Wood M, Goldberg S, Lau M, et al. Direct measurement of the lethal isotherm for radiofrequency ablation of myocardial tissue. Circ Arrhythm Electrophysiol. June 2011;4(3):373-378.


Ihnát P, Ihnát Rudinská L, Zonča P. Radiofrequency energy in surgery: state of the art. Surg Today. June 2014;44(6):985-991.


Nakagawa H, Yamanashi WS, Pitha JV, et al. Comparison of in vivo tissue temperature profile and lesion geometry for radiofrequency ablation with a saline-irrigated electrode versus temperature control in a canine thigh muscle preparation. Circulation. April 15, 1995;91(8):2264-2273.


Haines D. Biophysics of ablation: application to technology. J Cardiovasc Electrophysiol. October 2004;15(10 Suppl):S2-S11.


Oh S, Kilicaslan F, Zhang Y, et al. Avoiding microbubbles formation during radiofrequency left atrial ablation versus continuous microbubbles formation and standard radiofrequency ablation protocols: comparison of energy profiles and chronic lesion characteristics. J Cardiovasc Electrophysiol. January 2006;17(1):72-77.


Mittleman RS, Huang SK, de Guzman WT, Cuénoud H, Wagshal AB, Pires LA. Use of the saline infusion electrode catheter for improved energy delivery and increased lesion size in radiofrequency catheter ablation. Pacing Clin Electrophysiol. May 1995;18(5 Pt 1):1022- 1027.


Demazumder D, Mirotznik MS, Schwartzman D. Biophysics of radiofrequency ablation using an irrigated electrode. J Interv Card Electrophysiol. December 2001;5(4):377-389.


Chad E. Hamner et al: Irrigated Radiofrequency Ablation With Transmurality Feedback Reliably Produces Cox Maze Lesions In Vivo, Ann Thorac Surg 2005;80:2263–70


See the device manual for detailed information regarding the instructions for use, indications, contraindications, warnings, precautions, and potential adverse events. For further information, contact your local Medtronic representative and/or consult the Medtronic website at

For applicable products, consult instructions for use on Manuals can be viewed using a current version of any major internet browser. For best results, use Adobe Acrobat® Reader with the browser. 

This information is intended only for users in markets where Medtronic products and therapies are approved or available for use as indicated within the respective product manuals. Content on specific Medtronic products and therapies is not intended for users in markets that do not have authorization for use.