Cryoablation Trial Demonstrates Decrease in AF Symptoms


May 17, 2010

May 17, 2010 – New STOP AF (Sustained Treatment of Paroxysmal Atrial Fibrillation) clinical trial data showing the number of paroxysmal atrial fibrillation (AF) patients reporting AF symptoms declined by 80 percent after treatment with the Arctic Front Cardiac CryoAblation Catheter System. Additionally, as reported in the quality-of-life questionnaire results, all patients randomized and treated with the catheter system reported significant improvements in physical and mental quality-of-life factors.

These data were presented as a late breaking clinical trial at Heart Rhythm 2010 last week in Denver. The cryoablation system is commercially available in Europe and is under investigational use in the United States.

“The significant reduction in AF-related symptoms observed in this trial demonstrates the potential relief that cryoablation therapy can provide to patients suffering from symptomatic paroxysmal AF,” said Jeremy Ruskin, M.D., chair of the STOP AF trial steering committee, director of cardiac arrhythmia service at Massachusetts General Hospital. He also is associate professor of medicine at Harvard Medical School in Boston.

The number of patients randomized to cryoablation in the STOP AF trial who reported AF symptoms declined from 100 percent at baseline (pretreatment) to 20 percent at 12 months after cryoablation treatment. Specifically, when compared at baseline and 12 months, there was a reduction in the number of study participants who reported the following six symptom categories: palpitations (86 to 25 percent), fatigue (76 to 13 percent), rapid heart beat (66 to 16 percent), dyspnea, or difficulty breathing (54 to 9 percent), dizziness (48 to 9 percent), and syncope, or fainting (4 to 1 percent). To some AF patients, these symptoms can be debilitating.


The STOP AF pivotal clinical trial enrolled 245 patients at 26 U.S. and Canadian centers and studied the safety and effectiveness of the Medtronic Arctic Front Cardiac CryoAblation Catheter System in paroxysmal AF patients as compared to drug therapy. All primary safety and effectiveness endpoints in the trial were met. These results are part of the premarket approval submission under regulatory review by the U.S. Food and Drug Administration (FDA).

Cryoablation Catheter System

The catheter is designed to be used with fluoroscopy and does not require the use of complex, three-dimensional mapping systems. The technologies used in the STOP AF trial include:

• The catheter inflates and fills with coolant to ablate the tissue where the pulmonary veins enter the left atrium

• The FlexCath steerable sheath helps deliver and position the cryocatheter in the left atrium

• The Freezor Max Cardiac CryoAblation Catheter is a single-point catheter used to provide additional ablations, as needed

• The CryoConsole houses the coolant, electrical and mechanical components that run the catheters during a cryoablation procedure

The Arctic Front Cardiac CryoAblation system is investigational and not currently available for sale in the United States.

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