7.4 Mechanisms of Tachyarrhythmias

Sinus Tachycardia

Enhanced Automaticity

Abnormally fast impulse generation with a faster slope in phase 4

Enhanced Automaticity

Is caused by the autonomic nervous system, hypokalemia, hypoxia, or fiber stretch

Enhanced Automaticity

Premature ventricular contractions (PVCs)

Triggered activity

ventricular tachycardia

Triggered Tachycardia

Torsade de pointes

Triggered Tachycardia

Transient membrane depolarization during repolarization

Triggered Tachycardia

Caused by hypokalemia, or changes in ion channel activity

Triggered Tachycardia

atrial fibrillation

Re-entry

Atrial Flutter

Re-entry

Paroxysmal Supraventricular Tachycardia (PSVT)

Re-entry

Impulse propagation and activation of previously refractory tissue

Re-entry

Abnormal impulse conduction due to hypoxia, ischemia

Re-entry