Abstract 20771: Occult Structural Disease in Patients With Catecholaminergic Polymorphic Ventricular Tachycardia
Introduction: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a malignant genetic disorder of adrenergically-mediated polymorphic ventricular arrhythmias. Traditionally, it has been characterized by absence of structural heart disease. Recent case reports have linked CPVT due to exon 3 deletions in the ryanodine receptor (RYR2) gene to left ventricular noncompaction (LVNC).
Hypothesis: We hypothesized that structural heart disease would be evident on cardiac MRI in patients with clinically confirmed CPVT, despite normal echocardiograms.
Methods: We performed a retrospective observational analysis of families with CPVT, followed by the Stanford Inherited Arrhythmia Clinic, who had normal echocardiograms. Medical records, cardiac MRIs ordered for clinical indications, and genetic testing results were reviewed.
Results: Of 13 patients identified with CPVT, 10 had bidirectional or polymorphic ventricular ectopy on treadmill testing and 69% (9 patients) had suffered an aborted cardiac arrest. Genetic testing identified rare variants in RYR2 in 12 cases and compound heterozygous CASQ2 variants in one case. Cardiac MRIs were available for review in 6 patients. Structural abnormalities were observed in 3 patients, despite normal echocardiograms. Two patients with RYR2 exon 3 deletions had abnormal right ventricular relaxation or prominent left ventricular trabeculation, respectively. The third patient was found to have a novel missense variant in exon 2 of RYR2 (p.Lys34Gln, c.100A>C, NM_001035.2) with hypertrabeculation on MRI meeting diagnostic criteria for LVNC. This rare variant was absent in over 64,000 controls from ExAC, and cosegregated with ventricular bigeminy in the proband’s mother.
Conclusions: Although a small sample size, our findings suggest patients with CPVT may have more structural heart disease using more sensitive imagine techniques than traditionally appreciated. This is the also the first report of a patient with CPVT and a rare missense variant in RYR2 associated with LVNC. Larger studies are necessary to better define the prevalence and prognostic value of structural heart disease in patients with CPVT.
Author Disclosures: D.A. Gerber: None. A.M. Dubin: None. S.R. Ceresnak: None. K.S. Motonaga: None. K. Dunn: None. C. Caleshu: None. A. Smith: None. M. Jackson: None. M.V. Perez: Research Grant; Significant; Robert Wood Johnson Foundation.
- © 2016 by American Heart Association, Inc.