Info
VT versus SVT
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Electrocardiographic features that increase the likelihood of VT include:
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Absence of typical RBBB or LBBB morphology
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Extreme axis deviation (“northwest axis”): QRS positive in aVR and negative in I and aVF
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Very broad complexes > 160ms
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AV dissociation:
- P and QRS complexes at ↣ different rates
- P waves are often superimposed on QRS complexes and may be difficult to discern
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Capture beats: Occur when the sinoatrial node transiently “captures” the ventricles in the midst of AV dissociation, producing a QRS complex of normal duration
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Fusion beats: Occur when a sinus and ventricular beat coincide to produce a hybrid complex (see Dressler beat)