---
title: Thumb-ECG Ambulant Screening for Atrial Fibrillation in Patients Treated for Hyperthyroidism (TAMBOURINE)
nct_id: NCT01945229
overall_status: TERMINATED
sponsor: Karolinska Institutet
study_type: OBSERVATIONAL
primary_condition: Hyperthyroidism
countries: Sweden
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT01945229.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT01945229"
ct_last_update_post_date: 2020-09-04
last_seen_at: "2026-05-12T07:10:19.013Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# Thumb-ECG Ambulant Screening for Atrial Fibrillation in Patients Treated for Hyperthyroidism (TAMBOURINE)

**NCT ID:** [NCT01945229](https://clinicaltrials.gov/study/NCT01945229)

## Key Facts

- **Status:** TERMINATED
- **Why Stopped:** Preliminary analyses of data indicated study should be terminated for futility
- **Study Type:** OBSERVATIONAL
- **Target Enrollment:** 110
- **Lead Sponsor:** Karolinska Institutet
- **Conditions:** Hyperthyroidism, Atrial Fibrillation
- **Start Date:** 2014-02
- **Completion Date:** 2020-08
- **CT.gov Last Update:** 2020-09-04

## Brief Summary

Background: Atrial fibrillation is a common heart rhythm disturbance affecting some 1-2% of the western population. It may cause symptoms such as irregular heartbeats, shortness of breath, and fatigue. It may also be asymptomatic (ie "silent atrial fibrillation). In some cases, atrial fibrillation is permanent whereas in others it is sporadic. Regardless of symptoms, there is an increased risk of stroke in some patients with this condition. Novel technologies are being developed to increase detection of silent atrial fibrillation, in order to find patients who might benefit from treatment with oral anticoagulants (blood-thinning medications) in order to reduce the risk of stroke. One of these technologies is thumb-ECG, a simple way for a patient to have his or her heart rhythm reliably analyzed at home.

Hyperthyroidism (sometimes referred to as "toxic goiter") is defined as an excessive production of thyroid hormone. It is known that hyperthyroidism may cause atrial fibrillation in about 8% of cases.

Objective: To provide thumb-ECG-monitors to hyperthyroid patients before and after treating their hormonal disturbance, in order to find episodes of silent atrial fibrillation.

Design: Prospective observational study.

Hypotheses:

* Primary hypothesis: Silent atrial fibrillation is at least as common as overt atrial fibrillation in hyperthyroid patients.
* Secondary hypothesis nr 1: Atrial fibrillation continues to be more prevalent compared to the normal population even after hyperthyroidism is treated.
* Secondary hypothesis nr 2: The majority of patients with hyperthyroidism and atrial fibrillation are at increased risk of stroke and should be considered for treatment with oral anticoagulants.

## Eligibility

- **Sex:** ALL
- **Healthy Volunteers:** No

```
Inclusion Criteria:

* Patient is deemed suitable for treatment with radioiodine or antithyroid drugs
* Patient has a thyreotropin (TSH) value below 0,1 mIU/L, measured less than 2 weeks before inclusion
* Patient has a CHADS-VASc-score of 1 point or higher (excluding if 1 point is for female sex only)
* Patient gives written consent to participate in study

Exclusion Criteria:

* Patient has a previously known diagnosis of atrial fibrillation
```

## Arms

- **Hyperthyroid patients** — Patients with hyperthyroidism admitted for treatment with radioiodine or antithyroid drugs

## Primary Outcomes

- **Prevalence of asymptomatic (silent) atrial fibrillation in hyperthyroid patients** _(time frame: Upon inclusion and 2 weeks onwards)_ — Upon inclusion, each patient will receive a thumb-ECG-monitor to take home. He/she will register his/her heart rhythm twice daily, and can also register at will upon symptoms. This will continue for 2 weeks, after which the monitor is returned.

## Secondary Outcomes

- **Prevalence of asymptomatic (silent) atrial fibrillation in patients treated for hyperthyroidism.** _(time frame: Between 12 and 14 weeks after inclusion)_
- **Prevalence of risk factors for stroke in patients with atrial fibrillation** _(time frame: Momentary (day 1, upon inclusion))_

## Locations (3)

- Medicine Clinic, Sahlgrenska University Hospital, Gothemburg, Sweden
- Endocrinology Clinik, Karolinska University Hospital, Stockholm, Sweden
- Medicine Clinic, Danderyds Hospital, Stockholm, Sweden

## Recent Field Changes (last 30 days)

- `results.hasResults` — added _(2026-05-12)_
- `locations.medicine clinic, sahlgrenska university hospital|gothemburg||sweden` — added _(2026-05-12)_
- `locations.endocrinology clinik, karolinska university hospital|stockholm||sweden` — added _(2026-05-12)_
- `locations.medicine clinic, danderyds hospital|stockholm||sweden` — added _(2026-05-12)_
- `status.overallStatus` — added _(2026-05-12)_
- `status.whyStopped` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `outcomes.secondary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT01945229.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT01945229*  
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