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Ventricular Tachycardia: Difference between revisions
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*'''Polymorphic VT''': the ventricular beats have a changing configuration. The RR interval is 180-600 ms (comparable to a heart rate of 100-333 bpm). | *'''Polymorphic VT''': the ventricular beats have a changing configuration. The RR interval is 180-600 ms (comparable to a heart rate of 100-333 bpm). | ||
*'''Biphasic VT''': a ventricular tachycardia with a QRS complex that alternates from beat to beat. Associated with [[Miscellaneous#Digoxin|digoxin intoxication]] and [[lqts|long QT syndrome]]. | *'''Biphasic VT''': a ventricular tachycardia with a QRS complex that alternates from beat to beat. Associated with [[Miscellaneous#Digoxin|digoxin intoxication]] and [[lqts|long QT syndrome]]. | ||
==Localisation of the origin of a ventricular tachycardia== | |||
The localisation of the origin (or exit site) of a ventricular tachycardia can be helpful in understanding the cause of the VT and is very helpful when planning an ablation procedure to treat a ventricular tachycardia. | |||
The steps to finding the exit site are: | |||
# What is the bundle branch block (BBB) configuration? | |||
# What is the inferior lead QRS complex polarity | |||
# What is the lead I QRS complex polarity | |||
# What is the lead aVL QRS complex polarity | |||
# What is the lead aVR QRS complex polarity | |||
# Where is the R-wave transition point | |||
Using this approach and the algorithm on the right <cite>segal</cite> the exit site can be estimated with reasonable accuracy (PPV around 70%). | |||
==Examples== | ==Examples== | ||
<gallery > | <gallery > | ||
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File:DVA2161.jpg|A biphasic VT in a patient with long QT syndrome | File:DVA2161.jpg|A biphasic VT in a patient with long QT syndrome | ||
</gallery> | </gallery> | ||
==References== | |||
<biblio> | |||
#segal pmid=17338765 | |||
</biblio> | |||