Purpose

This is a randomized, placebo controlled trial of Dantrolene (N= 84 participants) to demonstrate the feasibility of using I.V. dantrolene to study the effect of RyR2 inhibition on cardiac electrophysiology, hemodynamics and ventricular arrhythmia inducibility in patients with structural heart disease referred for VT ablation. The investigators will also explore the pharmacokinetic/pharmacodynamic relationship of I.V. dantrolene and it short-term effect on specific cardiac electrophysiologic and hemodynamic parameters.

Condition

Eligibility

Eligible Ages
Over 18 Years
Eligible Genders
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • Greater than or equal to 18 years of age - Able to give written informed consent - Referred for catheter-based VT ablation - Structural heart disease (cardiomyopathy or RV/LV scar) - Permanent pacemaker or implantable cardioverter defibrillator

Exclusion Criteria

  • Mechanical ventricular support (e.g. LVAD, ECMO) - NYHA class IV heart failure - LVEF < 20% - Morbid obesity (BMI > 40 kg/m2) - Severe renal insufficiency (GFR<30 mL/min) - Chronic liver disease (Child Pugh class A-C) - Current use of calcium channel blockers - Neuromuscular disorder (e.g. muscular dystrophy) - Chronic obstructive pulmonary disease or restrictive lung disease requiring oxygen - Therapy or history of intubation - Pregnant or nursing - History of dysphagia

Study Design

Phase
Phase 2/Phase 3
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Intervention Model Description
84 participants will be randomly assigned in a 2:1 ratio to treatment (dantrolene) or control (placebo). A computer-generated randomization list will be prepared by the study statistician using the stratified permuted block randomization, where block size varies randomly from 4 or 6 to ensure overall balance across treatment arms. Randomization will be stratified by 1) documented CAD with prior infarct, 2) amiodarone use within the past 21 days defined as chronic oral use or >5 grams cumulative, 3) LVEF <35%. Enrollment will be evenly distributed across the two study arms by the stratification factors
Primary Purpose
Treatment
Masking
Double (Participant, Investigator)
Masking Description
The study statistician will generate the allocation schedule but will remain blinded to the treatment assignment as well as the study staff physician's. The research clinician will not be blinded.

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Dantrolene/Ryanodex
Dantrolene/Ryanodex; intravenous administration of dantrolene; 1 mg/ kg IV over 3 minute, one time dose
  • Drug: Dantrolene/Ryanodex
    muscle relaxant
    Other names:
    • Dantrium, Ryanodex
Placebo Comparator
Placebo
controlled placebo of saline administered Intravenous; 1 mg/kg IV over 3 minutes, one time dose
  • Drug: Placebo
    Controlled placebo of saline administered Intravenous; 1 mg/kg IV over 3 minutes, one time dose

Recruiting Locations

Vanderbilt University Medical Center
Nashville, Tennessee 37232
Contact:
William Stevenson, MD
615-322-2318
william.g.stevenson@vumc.org

More Details

Status
Recruiting
Sponsor
Vanderbilt University Medical Center

Study Contact

William Stevenson, MD
615-322-2318
william.g.stevenson@vumc.org

Detailed Description

The hypothesis to be tested is that RyR2 hyperactivity in patients with structural heart disease drives proarrhythmic changes in refractoriness and conduction, and decreases cardiac contractility, which promotes VT/VF. Dantrolene, a currently available drug that inhibits RyR2, but has no Na or K channel activity, will be used as a tool to study RyR2 modulation. The investigators propose a randomized controlled trial of dantrolene versus placebo in patients with structural heart disease referred for VT ablation to evaluate electrophysiologic, hemodynamic, and arrhythmia prevention endpoints. Dantrolene's inhibition of RyR1 will also be studied to define its effect on muscle and respiratory strength in this clinical population, which will be important if dantrolene is to be considered for repurposing as an antiarrhythmic drug. The two aims are: Aim 1: To conduct a randomized, placebo-controlled trial of dantrolene to study the effect of RyR inhibition on cardiac electrophysiology, hemodynamics, arrhythmia inducibility, muscle strength, and respiratory mechanics in patients with structural heart disease referred for VT ablation. Aim 2: To explore the pharmacokinetic/pharmacodynamic relationship of I.V. dantrolene and its short-term effect on cardiac electrophysiology, hemodynamics, and muscle and respiratory strength.

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.