o Wolff-Parkinson-White syndrome

o Wolff-Parkinson-White syndrome

Long-QT syndrome → torsade de pointes Long-QT syndrome can lead to V-fib directly, or may evolve to torsade de pointes tachycardia, which commonly leads to V-fib, syncope, and/or sudden cardiac death.

References: ^[1]

NOTES

FEEDBACK

Pathophysiology

· Normal electrical conduction can be disrupted by re-entry

→ chaotic, circulating excitation of the myocardium ( = ventricular fibrillation ) → simultaneous contractions at multiple foci → insufficient cardiac output → hemodynamic collapse → loss of consciousness and possibly death (sudden cardiac death)

· Re-entry can be caused by

o Changes to the conduction pathway (e. g., unexcitable scar tissue as a result of past myocardial infarction)

o Abnormal pattern of excitation, for example:

§ If the period of activation and recovery of myocardial cells

becomes greater than the duration of an action potential (as in long-QT syndrome )

§ If excitation occurs outside of the normal pattern of activation ( premature ventricular complex, PVC)

References: ^[1][2][3]

NOTES

FEEDBACK

Clinical features

· Possible early signs

o Chest pain

o Palpitation

o Fatigue

o Shortness of breath

o Dizziness

· Ultimately: loss of consciousness, death

References: ^[1][4]

NOTES

FEEDBACK

Diagnostics

ECG findings

· Ventricular fibrillation

o Commonly preceded by ventricular tachycardia

o General appearance

§ Arrhythmic, fibrillatory baseline, usually > 300 bpm

§ Erratic undulations with indiscernible QRS complexes

§ No atrial P waves

· Ventricular flutter: ventricular rates of ∼ 240–300 bpm

o Frequently transitions to V-fib

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