Arrhythmias - Ventricular
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Ventricular Tachycardia
Description:
3+ consecutive beats 120+ beats/minute; abnormal ventricular automacy.
Symptoms & Signs:
May be asymptomatic if duration is short (aka, paroxysmal) or rate is not excessive; If sustained, palpitations, difficulty breathing, chest pain, dizziness, fainting, death.
Treatments:
Cardioversion, antiarrhythmic drugs, defibrillator implant.
Risk Factors:
Heart disease, electrolyte imbalances, medications.
Clinical Concerns:
Can lead to heart failure, unconsciousness, sudden death by cardiac arrest.
Torsades de Pointes
Special case of ventricular tachycardia, associated with Long QT Syndrome.
Description:
Rapid, irregular QRS complexes "spiral" around baseline, as ventricular rate varies from cycle to cycle.
Symptoms & Signs:
Recurrent palpitations, dizziness, fainting, difficulty breathing.
Treatments:
Magnesium.
Risk Factors:
Electrolyte imbalances (hypocalcemia, hypokalemia); Medications (antiarrhythmics, tricyclic antidepressants, anti-histamines when taken with erythromycin. In individuals with Long QT Syndrome, can be triggered by stress, fear, etc.
Clinical Correlations:
Can lead to ventricular fibrillation, which is fatal.
Long QT Syndrome
Form of ventricular tachycardia, increases risk for Torsades de pointes.
Description:
Long QT interval on ECG, reflects defective ion channels.
Risk Factors:
Often inherited, but can be acquired (electrolyte imbalances, antihistamines, decongestants, diuretics, antiarrhythmic drugs, antidepressants, etc.). Inherited types may also be triggered by these medications.
Inherited types include Romano-Ward Syndrome (Types 1-3) and Jervell and Lange-Nielsen Syndrome, which is also associated with congenital deafness.
Clinical Correlations:
Prone to torsades de pointes, which can cause syncope, ventricular fibrillation, and sudden death.
Ventricular Fibrillation
Description:
Uncoordinated ventricular activity.
Symptoms & Signs:
Loss of consciousness, chest pain, dizziness, tachycardia.
Treatments:
CPR & Defibrillation
Risk Factors:
Ischemic heart disease, hypertrophic/dilated myopathies, Brugada syndrome, arrhythmic right ventricular dysplasia.
Clinical Concerns:
Cardiac arrest, Death