• Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a inherited disorder in which there are:
“leaky” ryanodine receptor (RyR) in the sarcoplasmic reticulum (SR), which releases Ca++ ions into the cytosol
dysfunctional calsequestrin (CASQ), a Ca-buffering protein in the SR
• As a result, there is Ca++ overload and increased risk of delayed afterderpolarizations (DAD) and ventricular arrhythmias.
• CPVT is often triggered by catecholamine (adrenergic stimulation).
• The resulting ECG rhythm is bidirectional ventricular tachycardia, which is also seen in digoxin toxicity.
