Ventricular arrhythmias are typically categorized by rate and rhythm regularity. Monomorphic ventricular tachycardia features a regular, wide-complex tachycardia with a consistent QRS morphology, whereas polymorphic VT shows varying QRS appearance and can include torsades de pointes. Ventricular fibrillation is a rapid, chaotic ventricular rhythm that usually results in lost effective circulation. Distinguishing these from supraventricular rhythms is essential, as management differs markedly.
Common causes include ischemic heart disease and post-infarction scar, cardiomyopathy, electrolyte disturbances (such as low potassium or magnesium), electrolyte or drug toxicity, congenital channelopathies, and structural heart disease. Ventricular arrhythmias can occur in otherwise healthy individuals but are more often seen in patients with underlying cardiac pathology.
Symptoms range from palpitations and dizziness to syncope and sudden cardiac arrest, depending on stability and rhythm. Diagnosis relies on ECG findings: wide QRS complexes for VT, irregular rapid activity for VF, and potential signs of hemodynamic compromise. Additional testing may include echocardiography, coronary imaging, and consideration of underlying etiologies.
Acute management depends on stability. Unstable VT or VF requires immediate defibrillation; synchronized cardioversion is used for unstable VT with a pulse. Stable VT may be treated with antiarrhythmic drugs such as amiodarone or lidocaine; magnesium is essential for torsades de pointes. Long-term strategies include treating the underlying heart disease, pharmacologic suppression, and, in high-risk patients, implantation of an implantable cardioverter-defibrillator (ICD) or catheter ablation for focal or scar-related VT. Prognosis varies with cause, but ventricular arrhythmias carry a significant risk of morbidity and sudden cardiac death if not managed appropriately. See also ventricular tachycardia, ventricular fibrillation, and sudden cardiac death.