Sudden death and cardiac arrests frequently occur without explanation, even following thorough evaluation. Calcium Release Deficiency Syndrome (CRDS) is a life-threatening genetic arrhythmia syndrome where-in affected patients possess a loss-of function variant in the cardiac ryanodine receptor gene (RyR2). CRDS is presently undetectable with standard testing leading to cardiac arrests labeled as unexplained.

The Evaluation of a Novel Diagnostic Test for Calcium Release Deficiency Syndrome (DIAGNOSE CRDS) study, looks to evaluate the ability of the response to ventricular and atrial burst pacing to serve as a diagnostic test for CRDS and distinguish affected participants from survivors of unexplained cardiac arrest (UCA) that do not possess an RyR2 loss-of-function variant, genotype positive (RyR2 and CASQ2) catecholaminergic polymorphic ventricular tachycardia (CPVT) participants, and participants with supraventricular tachycardia (SVT) and structurally normal hearts.

In the DIAGNOSE CRDS study, we hypothesize that in response to pacing trains (both atrial and ventricular) and a post-pacing pause, CRDS participants will manifest with abnormal QT prolongation and a T-wave that is broad and tall on the first post-pacing beat. These findings will not be observed in control participants with structurally normal hearts, RyR2-CPVT participants, or survivors of UCA that do not possess an RyR2 loss-of-function variant.

Study Type

Observational with Invasive Assessments

Study Design

Multi-centre, primarily prospective cohort study

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Population Health Research Institute

Canadian Institutes of Health Research (CIHR)

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