Differential Diagnosis for Monomorphic Ventricular Tachycardia (VT)
Single Most Likely Diagnosis
- Ventricular Tachycardia (VT) due to re-entrant mechanism: This is the most common cause of monomorphic VT, often occurring in the setting of previous myocardial infarction or other structural heart diseases. The re-entrant circuit typically involves areas of scarred myocardium.
Other Likely Diagnoses
- Idiopathic VT: Originates from the right ventricular outflow tract or the left ventricle, often without any identifiable structural heart disease. It tends to be more common in younger individuals without a history of heart disease.
- Bundle Branch Re-entrant VT: A form of VT that uses the bundle branches as part of the re-entrant circuit, more commonly seen in patients with dilated cardiomyopathy or other conditions affecting the conduction system.
Do Not Miss Diagnoses
- Torsades de Pointes: Although typically polymorphic, in some cases, it can present with a monomorphic pattern, especially if the QT interval is prolonged due to various medications, electrolyte imbalances, or congenital conditions.
- Supraventricular Tachycardia (SVT) with Aberrancy: SVTs, such as atrioventricular nodal re-entrant tachycardia (AVNRT) or atrioventricular re-entrant tachycardia (AVRT), can conduct aberrantly through the ventricles, mimicking VT. Identifying the correct diagnosis is crucial as the treatment differs significantly.
Rare Diagnoses
- Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT): Although more commonly associated with polymorphic VT, it can rarely present with monomorphic patterns, especially in the context of familial conditions or genetic predispositions.
- Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): A rare condition characterized by fibrofatty replacement of the right ventricular myocardium, which can lead to various arrhythmias, including monomorphic VT.