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NCT Number: NCT07270211

MCG In Long QT Syndrome

The primary objective of this observational study is to evaluate whether magnetocardiography (MCG) findings more accurately predict clinical outcomes in patients with acquired Long QT syndrome compared to ECG. The secondary objective is to assess differences in QT interval length between MCG and ECG. The primary safety objective is to characterize the safety profile of the CardiAQ MCG device.

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Key information

Conditions

Atrial Fibrillation Arrhythmias, Cardiac Cardiovascular Diseases Heart Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Mayo Clinic in Rochester

Rochester, Minnesota, 55905, United States

Location contact

Mohamad Alkhouli, MD

PRINCIPAL_INVESTIGATOR

Structural Heart Research Team

CONTACT

(507) 255-6133

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years on the date of consent
  • Ability for participant to comply with study requirements
  • Written informed consent
  • Confirmed diagnosis of atrial fibrillation and receiving dofetilide for rhythm control in the inpatient setting.

Exclusion criteria

  • Pregnant or breastfeeding
  • Active thoracic metal implants (including pacemaker, insertable cardiac monitor, or internal defibrillators).
  • External electrical pads or devices (e.g. Pacer pads, ECG electrodes, heart rate patch), that must remain on patient's chest during MCG scan
  • Inability to lie down in a supine/inclined position and stay still on the examination bed
  • Clinical conditions that in the opinion of the Investigator would compromise the safety of the patient or ability to complete the protocol

Treatment and study plan

Magnetocardiography

Diagnostic Test

MCG is a non-invasive, radiation-free imaging technique that detects the magnetic field generated by the electrical activity of the heart.

Primary outcomes

  1. Number of successful dofetilide loading using Magnetocardiography

    Time frame: Baseline

    Dofetilide loading is considered successful if the following conditions are met:

    • No excessive QTc prolongation QTc remains <500 ms, and no >15% increase from baseline.
    • No sustained VT or recurrent/symptomatic non-sustained VT (NSVT) suggestive of proarrhythmia.
    • No symptomatic bradycardia or hemodynamic instability
    • Stable renal function
    • No deterioration necessitating dose reduction or discontinuation.
    • Discharge on a stable dose

  2. Number of successful dofetilide loading using Electrocardiogram

    Time frame: Baseline

    Dofetilide loading is considered successful if the following conditions are met:

    • No excessive QTc prolongation QTc remains <500 ms, and no >15% increase from baseline.
    • No sustained VT or recurrent/symptomatic non-sustained VT (NSVT) suggestive of proarrhythmia.
    • No symptomatic bradycardia or hemodynamic instability
    • Stable renal function
    • No deterioration necessitating dose reduction or discontinuation.
    • Discharge on a stable dose

Secondary outcomes

  1. Magnetocardiography - QT interval length

    Time frame: Baseline

    QT interval length is a measurement from the start of the Q wave to the end of the T wave. This will be measured in seconds.

  2. Electrocardiogram - QT interval length

    Time frame: Baseline

    QT interval length is a measurement from the start of the Q wave to the end of the T wave. This will be measured in seconds.

Study contacts

Contact information is provided by the study sponsor or research team.

Patsy Caceres Figueroa

CONTACT

[email protected]

507-266-3054

Sponsors and collaborators

Lead sponsor

Mayo Clinic

Other

Registry information

Official study title

Magnetocardiography in Long QT Syndrome: A Prospective Study of Its Clinical and Prognostic Utility

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Dec 8, 2025
Registry last updated
Mar 5, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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