ISRCTN - ISRCTN46168176: Cryoablation of atrial flutter

Plain English Summary

Background and study aims
Atrial flutter is an abnormality in the beating of the heart, also known as arrhythmias. This arrhythmia can be the cause of stroke, heart failure and eventually death. This heart condition is successfully treatable today with catheter ablation, which destroys a small area of heart tissue that is causing rapid and irregular heartbeats. The aim of this study was to compare two commonly used catheter ablation technologies, namely radiofrequency (burning of the tissue), which is the standard treatment, and cryoablation (freezing of the tissue), which is the alternative treatment.

Who can participate?
All patients regardless of age and gender with clear atrial flutter symptoms can participate in this study.

What does the study involve?
In order to evaluate heart function, patients undergo a clinical examination, ECG recording and echocardiography. Patients will then be randomly allocated to be treated with either radiofrequency or cryoablation. Six months after treatment all patients will be followed up with an out-patient visit and an ECG recording.

What are the possible benefits and risks of participating?
The possible benefits of participating are that cryoablation is practically painless and equally effective to standard treatment (radiofrequency). No risks have been shown in the clinical studies published so far.

Where is the study run from?
The study is run from Karolinska University Hospital, Stockholm, Sweden.

When is the study starting and how long is it expected to run for?
The study ran from January 2007 to November 2010.

Who is funding the study?
Financial support was provided through the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and the Karolinska Institute (Sweden).

Who is the main contact?
Dr Hamid Bastani
Karolinska University Hospital, Stockholm, Sweden

Trial website

Contact information

Type

Scientific

Primary contact

Prof Mats Jensen-Urstad

ORCID ID

Contact details

Department of Cardiology
Karolinska Institute
Karolinska University Hospital
Stockholm
14186
Sweden
mats.jensen-urstad@karolinska.se

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

Scientific title

Cryothermal versus Radiofrequency Ablation as atrial Flutter Therapy: a randomized comparison

Acronym

CRAFT

Study hypothesis

Catheter ablation with cryothermal energy is non-inferior to ablation with radiofrequency energy for the treatment of cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL)

Ethics approval

Regional Ethical Review Board, Stockholm, 2006, ref: 1006-31

Study design

Prospective single-blinded randomized controlled single-centre trial

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Hospitals

Trial type

Treatment

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Atrial flutter

Intervention

Cryo group:
Cryo was delivered with the use of a steerable 9F, 8-mm-tip catheter (Freezor MAX, CryoCath, Quebec, Canada), which was positioned on the TV annulus. Cryoablation was then performed using a sequential application technique point-by-point from the TV annulus to the inferior vena cava (IVC).

RF group:
RF was performed using a 7F 3.5-mm open-irrigated-tip catheter (Biosense-Webster Inc., Diamond Bar, CA. USA) to create an ablation line between the tricuspid valve and the IVC.

Intervention type

Other

Phase

Not Applicable

Drug names

Primary outcome measure

Clinical success defined as the freedom from atrial flutter evaluated at the 6-month follow-up.

Secondary outcome measures

1. Acute ablation success defined as bidirectional CTI-block safety assessed by the rate of periprocedural complications, procedure and fluoroscopy times and the level of pain experienced by the patient during the ablation procedure
2. To compare the utility of non-fluoroscopic mapping systems (Ensite NavX) with conventional mapping all patients were also randomized to either fluoroscopy only or Ensite NavX and fluoroscopy

Overall trial start date

01/01/2007

Overall trial end date

30/11/2010

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

1. Consecutive patients referred to our institution for ablation therapy of ECG-documented typical CTI-dependent AFL
2. Patients above the age of 18 with symptomatic CTI-dependent AFL documented on a 12-lead ECG with typical ECG appearance of negative saw tooth waves in the inferior limb leads and positive deflections in V1 or positive saw tooth waves in the inferior limb leads and negative deflections in V1
3. Patients with a history of atrial fibrillation included if they had predominant atrial flutter under chronic treatment with class I or III antiarrhythmic agents

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

150

Participant exclusion criteria

1. Prior ablation for AFL
2. Atrial flutter related to recently undergone surgery, hyperthyroidism or other severe disease
3. Inability to adhere to the study protocol
4. Pregnancy
5. Predominant atrial fibrillation
6. Contraindication to warfarin

Recruitment start date

01/01/2007

Recruitment end date

30/11/2010

Locations

Countries of recruitment

Sweden

Trial participating centre

Department of Cardiology
Stockholm
14186
Sweden

Sponsor information

Organisation

Karolinska University Hospital (Sweden)

Sponsor details

Department of Cardiology
Stockholm
141 86
Sweden
+46 8 585 800 00
mats.jensen-urstad@karolinska.se