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

Atrial Fibrillation Clinical Trial

— TABLAS  

Official title:

Observational Prospective Case-control Study on Prevalence and Impact of Subclinical Hyperthyroidism in Patients Undergoing Atrial Fibrillation Ablation

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01789541
• Other study ID #: 3/9A
• Status: Completed
• Phase: N/A
• First received: February 5, 2013
• Last updated: January 19, 2016
• Start date: February 2013
• Est. completion date: November 2015

Study information

• Verified date: January 2016
• Source: Karolinska Institutet
• Contact: n/a
• Is FDA regulated: No
• Health authority: Sweden: Regional Ethical Review BoardSweden: The National Board of Health and Welfare
• Study type: Observational

Clinical Trial Summary

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 327
• Est. completion date: November 2015
• Est. primary completion date: October 2015
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years and older

Eligibility

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

Study Design

Observational Model: Case Control, Time Perspective: Prospective

Related Conditions & MeSH terms

• Atrial Fibrillation
• Hyperthyroidism
• Subclinical Hyperthyroidism

Locations

Country	Name	City	State
Sweden	Hjärtkliniken, Karolinska Universitetssjukhuset Huddinge	Stockholm
Sweden	Stockholm Arrhythmia Center	Stockholm

Sponsors (1)

Lead Sponsor	Collaborator
Karolinska Institutet

Country where clinical trial is conducted

Sweden, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Prevalence of subclinical hyperthyroidism in patients undergoing atrial fibrillation ablation		1 day (Measured upon inclusion)	No
Secondary	Recurrent atrial fibrillation after ablation		6 months	No