Insights Into the Pathogenesis of Catecholaminergic Polymorphic Ventricular Tachycardia From Engineered Human Heart Tissue

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        <jats:title>Methods:</jats:title>
        <jats:p>Here, we report an optogenetically based, human engineered tissue model of catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited arrhythmia caused by mutation of the cardiac ryanodine channel and triggered by exercise. We developed a human induced pluripotent stem cell–derived cardiomyocyte–based platform to study the tissue-level properties of engineered human myocardium. We investigated pathogenic mechanisms in CPVT by combining this novel platform with genome editing.</jats:p>
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        <jats:title>Results:</jats:title>
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          In our model, CPVT tissues were vulnerable to developing reentrant rhythms when stimulated by rapid pacing and catecholamine, recapitulating hallmark features of the disease. These conditions elevated diastolic Ca
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          levels and increased temporal and spatial dispersion of Ca
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          wave speed, creating a vulnerable arrhythmia substrate. Using Cas9 genome editing, we pinpointed a single catecholamine-driven phosphorylation event, ryanodine receptor–serine 2814 phosphorylation by Ca
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          /calmodulin-dependent protein kinase II, that is required to unmask the arrhythmic potential of CPVT tissues.
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        <jats:title>Conclusions:</jats:title>
        <jats:p>Our study illuminates the molecular and cellular pathogenesis of CPVT and reveals a critical role of calmodulin-dependent protein kinase II–dependent reentry in the tissue-scale mechanism of this disease. We anticipate that this approach will be useful for modeling other inherited and acquired cardiac arrhythmias.</jats:p>
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