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Study Comparing Quinidine and Verapamil for Patients with Short-Coupled Idiopathic Ventricular Fibrillation

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a heart condition known as Short-coupled Idiopathic Ventricular Fibrillation (IVF). This condition involves irregular heartbeats that can lead to serious heart rhythm problems. The study is comparing two medications, Quinidine and Verapamil, to see which one is more effective and safe for treating this condition. Both medications are taken orally, meaning they are swallowed in pill form.

The purpose of the study is to determine if a larger, more definitive trial is advisable and feasible. Participants in the study will receive both medications at different times. This is known as a crossover study, where each participant tries both treatments. The study will last for a period of 18 months, during which participants will be monitored for any changes in their heart rhythm and any side effects they might experience.

Throughout the study, the main focus will be on observing any sustained irregular heartbeats, known as ventricular arrhythmias, which are serious heart rhythm disturbances. The results will help researchers understand which medication might be better for managing this heart condition in the future.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, eligibility is confirmed based on specific criteria related to short-coupled idiopathic ventricular fibrillation. This includes having a functioning implantable cardioverter-defibrillator (ICD) and a history of certain cardiac events.

    Genetic testing is initiated, although results are not required at the time of inclusion.

  2. Step 2

    Treatment period with quinidine

    The first treatment period involves taking quinidine orally. The dosage and frequency are determined by the study protocol and are monitored by the research team.

    During this period, the focus is on assessing the safety and effectiveness of quinidine in preventing arrhythmic events.

  3. Step 3

    Crossover to verapamil

    After completing the quinidine treatment period, there is a transition to the second treatment period with verapamil, also taken orally.

    Similar to the quinidine period, the dosage and frequency are specified by the study protocol, and the effects on arrhythmic events are closely monitored.

  4. Step 4

    Evaluation and scoring

    Throughout both treatment periods, the occurrence of sustained ventricular arrhythmia is evaluated using a severity scoring system.

    The highest applicable score during each treatment period is recorded to assess the primary endpoint of the study.

  5. Step 5

    Completion of the study

    The study is estimated to conclude by September 2027. At the end of the study, data from both treatment periods are analyzed to determine the advisability and feasibility of a larger trial comparing quinidine and verapamil.

Who can join the trial?

8 criteria

  • Must have at least one of the following diagnostic criteria for short-coupled Idiopathic Ventricular Fibrillation (IVF):
    • Diagnosis based on any documentation like ECG (a test that records the heart's electrical activity), Holter monitor (a portable device for continuous heart monitoring), device electrogram (EGM), or telemetry showing PVT (a type of irregular heartbeat) of 3 or more consecutive beats or VF (a serious heart rhythm problem) started by a PVC (a premature heartbeat) with a coupling interval less than 350 milliseconds.
    • Isolated PVCs with a coupling interval less than 350 milliseconds during the initial hospital stay after a sudden cardiac arrest or fainting due to a shockable rhythm or presumed arrhythmogenic syncope (a temporary loss of consciousness due to heart rhythm issues).
    • Carrier of the DPP6 haplotype (a specific genetic variation).
    • Must have a functioning ICD (Implantable Cardioverter Defibrillator), which can be placed through veins (transvenous) or under the skin (subcutaneous).
    • Must have experienced sudden cardiac arrest, near fainting, appropriate ICD shock, or nonsustained PVT documented by the ICD at least once in the past 2 years.
    • Genetic testing must have been started, but results are not needed at the time of joining the study. If you are a family member of someone with the DPP6 gene, other genes do not need to be tested.
    • Must be willing to undergo two treatment periods with the medications verapamil and quinidine.
    • Must be 18 years of age or older.

Who cannot join the trial?

3 criteria

  • Patients who are not within the specified age range for the study.
  • Patients who do not have the specific heart condition called Short-coupled Idiopathic Ventricular Fibrillation. This is a type of irregular heartbeat that occurs without a known cause.
  • Patients who are part of a vulnerable population, which means they might need special protection or care.
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Investigated drugs

  • Quinidine

    is a medication used to treat certain types of irregular heartbeats, such as ventricular fibrillation. In this trial, it is being tested to see how effective and safe it is for patients with short-coupled idiopathic ventricular fibrillation.

  • Verapamil

    is another medication used to treat heart rhythm problems. It works by relaxing the muscles of the heart and blood vessels. In this study, it is being compared to quinidine to evaluate its effectiveness and safety in managing short-coupled idiopathic ventricular fibrillation.

What is already known about the treatment

  • Quinidine

    Quinidine is administered orally in tablet form and is currently being studied in clinical trials for its effectiveness in treating short-coupled idiopathic ventricular fibrillation. It is a well-known antiarrhythmic medication used to manage certain types of irregular heartbeats. Quinidine works by blocking specific ion channels in the heart, which helps to stabilize the heart's electrical activity. It belongs to the pharmacological class of Class IA antiarrhythmic agents.

  • Verapamil

    Verapamil is available in oral tablet form and is under investigation in clinical trials for its potential use in treating short-coupled idiopathic ventricular fibrillation. It is commonly used to treat high blood pressure and certain types of arrhythmias. Verapamil functions by inhibiting calcium channels in the heart and blood vessels, leading to a decrease in heart rate and blood pressure. It is classified as a calcium channel blocker.

Investigated diseases

Short-coupled Idiopathic Ventricular Fibrillation – This is a rare heart condition characterized by irregular and rapid heartbeats originating from the ventricles, which are the lower chambers of the heart. The term "short-coupled" refers to the brief interval between the heartbeats that trigger the arrhythmia. It occurs without any identifiable structural heart disease or other known causes. The condition can lead to episodes of fainting or dizziness due to the heart's inability to pump blood effectively during these arrhythmic events. It is often diagnosed in young, otherwise healthy individuals. The progression of the disease involves recurrent episodes of ventricular fibrillation, which can vary in frequency and severity.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-511190-30-00Estimated enrolment24 patientsSponsorAmsterdam UMC

sourced from the EU Clinical Trials Register and site verification

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