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Flecainide and QT intervals
anonymous854 posted:
From what I've read, Flecainide typically prolongs the QT interval. However, mine has decreased from around 440 to 400. I've ready that this is suggestive of LQTS but I have never had a long QT reading. Is this shortening normal of Flecainide? It has slightly prolonged all other intervals on my ECG.
cardiostarusa1 responded:

"Is this shortening normal of Flecainide?"

It may/can have this effect, as reported, in some individuals under certain or specific circumstances.

Randomly-selected info (contains med-speak)

Long QT syndrome

Emerging treatments


Flecainide is a class IC anti-arrhythmic drug with potent sodium channel-blocking properties. Patients with LQT3 mutations have an abnormal sodium channel allowing an inward current to persist long into the plateau phase of the potential, thereby prolonging the QT interval. In these patients, flecainide has been shown to shorten and even normalise the QT interval......

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For those not familiar with the QT interval.

QT interval (includes info on prolonged QT)

Best of luck down the road of life.

Take care,


WebMD community member (8/99)



It's your there.


WebMD/WebMD forums does not provide medical advice, diagnosis or treatment.
anonymous854 replied to cardiostarusa1's response:
Can this be normal in those without LQTS as well, as I have never had a long QT??
cardiostarusa1 replied to anonymous854's response:
It may/could be, as anything medical is seemingly possible today, especially when it comes to the heart's electrical conduction system, and the various effects on it.

Take good care,




Be well-informed

Heart Rhythm Society

Patient and Public Information Center




The Heart: (Human Anatomy) Pictures, Definition, Location in the Body and Heart Problems


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