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

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

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT01789541

Acronym

TABLAS

Enrollment

327

Registered

2013-02-12

Start date

2013-02-28

Completion date

2015-11-30

Last updated

2016-01-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Atrial Fibrillation, Subclinical Hyperthyroidism

Brief 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.

Interventions

None listed

Study design

Observational model

CASE_CONTROL

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

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

Design outcomes

Primary

Measure	Time frame
Prevalence of subclinical hyperthyroidism in patients undergoing atrial fibrillation ablation	1 day (Measured upon inclusion)

Secondary

Measure	Time frame
Recurrent atrial fibrillation after ablation	6 months

Countries

Sweden

Outcome results