Mechanisms of Tachycardias

• Abnormalities in impulse generation (automatic tachycardias)

• Abnormalites in impulse conduction

(reentrant tachycardias)

Clinical examples

• Atrial fibrillation

• Reentrant PSVT

• Ventricular tachycardia/fibrillation

Atrial Fibrillation - causes

• Atrial stretch

• High sympathetic tone

• Idiopathic or “lone”

Atrial fibrillation - complications

• Worsened heart failure

• Recurrences

• Thromboembolism (CVA 3-5%/yr)

Reentrant PSVT

• AV Nodal Reentry

• AV Reentry (WPW)

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