Is a Low Thyreotropin Level Predictive of Recurrent Arrhythmia After Catheter Ablative Surgery? (TABLAS)

This study is currently recruiting participants. (see Contacts and Locations)
Verified January 2015 by Karolinska Institutet
Information provided by (Responsible Party):
Peter Giesecke, M.D, Karolinska Institutet Identifier:
First received: February 5, 2013
Last updated: January 29, 2015
Last verified: January 2015

Overt hyperthyroidism (so-called "goiter" in lay language) is a hormonal disturbance that is known to increase the risk of atrial fibrillation (a common heart arrhythmia with potentially severe consequences) in some patients. Previous research has indicated that even slight elevations in thyroid hormone levels - so called subclinical hyperthyroidism - may increase this risk. When atrial fibrillation and overt hyperthyroidism are found simultaneously in a patient, the hormonal imbalance must be treated first in order to later resolve the arrhythmia. It is unclear whether this strategy holds true for subclinical hyperthyroidism. Our two hypotheses are: 1) Subclinical hyperthyroidism is more prevalent in patients admitted for atrial fibrillation ablation than in the population as a whole, and 2) Patients with subclinical hyperthyroidism and atrial fibrillation benefit less from ablation than others.

As a control group, we have chosen patients admitted for ablation of AV-nodal Reentry Tachycardia at the same clinics as the cases. No correlation has ever been shown between AV-nodal Reentry Tachycardia and hyperthyroidism.

Atrial Fibrillation
Subclinical Hyperthyroidism

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Prospective
Official Title: Observational Prospective Case-control Study on Prevalence and Impact of Subclinical Hyperthyroidism in Patients Undergoing Atrial Fibrillation Ablation

Resource links provided by NLM:

Further study details as provided by Karolinska Institutet:

Primary Outcome Measures:
  • Prevalence of subclinical hyperthyroidism in patients undergoing atrial fibrillation ablation [ Time Frame: 1 day (Measured upon inclusion) ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Recurrent atrial fibrillation after ablation [ Time Frame: 6 months ] [ Designated as safety issue: No ]

Estimated Enrollment: 458
Study Start Date: February 2013
Estimated Study Completion Date: August 2015
Estimated Primary Completion Date: February 2015 (Final data collection date for primary outcome measure)
Atrial fibrillation
Patients with atrial fibrillation undergoing ablation
AV-nodal reentry tachycardia
Patients with AV-Nodal Reentry Tachycardia undergoing ablation


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population

Patients with atrial fibrillation (cases) or AV-nodal reentry tachycardia (controls)


Inclusion Criteria:

  • Atrial fibrillation or AV-nodal reentry tachycardia
  • Fulfills criteria for ablation (severe arrhythmia symptoms; for atrial fibrillation patients, having tried at least one antiarrhythmic agent with poor effect)
  • Admitted for ablation for the first time
  • Has left blood samples for thyroid status (TSH, free T4, free T3)

Exclusion Criteria:

  • Atrial flutter
  • Overt hyperthyroidism
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01789541

Contact: Peter Giesecke, M.D. +46 70 768 43 88

Hjärtkliniken, Karolinska Universitetssjukhuset Huddinge Recruiting
Stockholm, Sweden, 14147
Contact: Mats Jensen-Urstad, M.D.    +46 8 5858 00 00      
Stockholm Arrhythmia Center Recruiting
Stockholm, Sweden, 11861
Contact: Fariborz Tabrizi, M.D.    +46 8 616 52 00      
Sponsors and Collaborators
Karolinska Institutet
Study Chair: Mårten Rosenqvist, Professor Karolinska Institutet, Institutionen för kliniska vetenskaper vid Danderyds sjukhus
  More Information

No publications provided

Responsible Party: Peter Giesecke, M.D, M.D., Karolinska Institutet Identifier: NCT01789541     History of Changes
Other Study ID Numbers: 3/9A
Study First Received: February 5, 2013
Last Updated: January 29, 2015
Health Authority: Sweden: Regional Ethical Review Board
Sweden: The National Board of Health and Welfare

Additional relevant MeSH terms:
Atrial Fibrillation
Arrhythmias, Cardiac
Cardiovascular Diseases
Endocrine System Diseases
Heart Diseases
Pathologic Processes
Thyroid Diseases processed this record on March 31, 2015