Ventricular Arrhythmias

Snapshot

• A 57-year-old woman presents to the emergency department after fainting. He was accompanied by his wife who witnessed the event. He was in his usual state of health until he developed palpitations that eventually resulted in him falling to the ground. He was unresponsive and the emergency medical services were called. Medical history is significant for a recent myocardial infarction. On physical exam he is unresponsive and no pulse is present. An electrocardiogram demonstrates a tachyarrhythmia with irregular QRS complexes of variable amplitude and morphology. (Ventricular fibrillation)

Introduction

• A group of ventricular arrhythmias that include
  • ventricular premature beats 
    • action potentials are ectopically generated within the ventricles
    • typically benign and asymptomatic
  • ventricular tachycardia
    • if sustained ventricular tachycardia is not managed, it can result in ventricular fibrillation
  • ventricular fibrillation
    • life-threatening, if not immediately managed
• Epidemiology
  • risk factors
    • myocardial ischemia and infarction 
    • ventricular hypertrophy
    • long QT syndromes
    • valvular heart disease
    • congenital cardiac abnormalities
• Symptoms
  • palpitations
  • symptoms of heart failure, which include
    • shortness of breath
    • chest discomfort
    • syncope
• cardiac arrest