With regards to the prognosis, it is important that the medications are taken regularly and restrict the amount of exercise. This would be difficult at first especially with her love of swimming but with your help and support, this may work out well. Read about the condition to understand it more. Talk to your doctor about this and have regular follow-ups for monitoring.
HI,
How is your niece? CPVT is a rare condition that affects the heart of otherwise fit and healthy people. It causes the heart to beat abnormally quickly, usually at times of exercise such as swimming, or times of high emotion, and can result in dizziness, sudden
loss of consciousness or even death. It most commonly occurs in children and young adults.
CPVT usually responds well to beta-blockers, although beta-blockers are usually used in combination with implantable defibrillators (AICDs; automatic implantable cardioverter defibrillators). Take care and regards.
I hope your niece is recovering well. The only thing I can tell you is I have CPVT and have had it since I was 10 years old (33 now). If the doctors haven't already they will probably implant an ICD which will act like her own portable EMT. It monitors her heart constantly and will deliver therapy if needed. She will also probably be on medication such as a beta blocker. The doctors will also probably restrict any competitive activity. CPVT.