Atropine in Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)

Study Overview
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Brief Summary
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To test the hypothesis that increasing the sinus node rate with atropine treatment prior to exercise will reduce exercise-triggered ventricular ectopy compared to baseline in patients with CPVT.

Detailed Description
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This is a prospective cross-over trial that will enroll eligible patients with CPVT and perform a baseline treadmill exercise tolerance test (ETT) followed by a repeat treadmill ETT with I.V. atropine administered immediately prior to exercise. Atropine is a parasympathetic blocker and results in sinus tachycardia, which is expected to reduce the diastolic interval thereby reducing delayed after depolarizations and ventricular ectopy compared to baseline. Both ETTs will be performed on the same day with two hours of rest scheduled between ETTs. The primary analysis will be a paired comparison of the number of ventricular ectopic beats recorded during exercise (and recovery) at baseline and following pre-treatment with atropine. Secondary endpoints will include the presence of ventricular ectopy (yes/no), complex ventricular ectopy (couplets or greater, yes/no), and the number of runs of complex ventricular ectopy.

Official Title
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Pretreatment With Atropine to Reduce Exercise-triggered Ventricular Ectopy in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)

Conditions
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Catecholaminergic Polymorphic Ventricular Tachycardia

Intervention / Treatment
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* Drug: Atropine
* Procedure: Exercise treadmill test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age >/= 6 years Able to provide written informed consent Clinical diagnosis of CPVT Able to exercise on a treadmill Successful completion of a minimum of 2 exercise stress tests without adverse events Exclusion Criteria: Contraindication to treadmill stress testing according to Vanderbilt University Medical Center's clinical protocols (unstable angina, decompensated congestive heart failure, severe hypertension (≥ 170/90 mmHg), acute myocardial infarction (<4 days), moderate to severe aortic stenosis, acute pulmonary embolism, severe pulmonary hypertension, outflow tract obstruction, hypertrophic cardiomyopathy, left main coronary stenosis, left bundle branch block) Females who are pregnant In the judgement of the investigator, any clinically significant ongoing medical or surgical condition that might jeopardize the subject's safety or interfere with the conduct of the study

Ages Eligible for Study
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Minimum Age: 6 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Treadmill then Treadmill with Atropine<br>Patients will undergo treadmill exercise at baseline, then Patients will undergo treadmill exercise after IV atropine | Drug: Atropine<br> <br> Procedure: Exercise treadmill test<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Ventricular Ectopic Beats Recorded During Exercise (and Recovery) |  | 20 minutes during exercise |