Ventricular Tachycardia
Ventricular tachycardia (VT) is a fast heart rhythm that is generated by abnormal ventricular tissue. Ventricular tachycardia is often associated with the presence of structural heart disease. Examples include scar from previous heart attacks, valvular heart disease, heart surgery, or congenital heart defeats. There are also a variety of idiopathic ventricular tachycardias, some of which are now being defined as heritable disorders in patients with otherwise normal cardiac function.
The gold standard of treatment in patients with symptomatic sustained ventricular tachycardia associated with scar and coronary artery disease is implantation of an internal cardiac defibrillator (ICD). Radiofrequency ablation may be used adjunctively in patients who have drug-refractory sustained ventricular tachycardia, or who cannot tolerate medication required to suppress ventricular tachycardia.
Idiopathic VT (i.e., not associated with identifiable structural heart disease) most commonly arises from the right or left ventricular outflow tract. Less commonly it originates in the inferoseptal left ventricle near the apex or other sites. These forms of VT are amenable to catheter ablation.
Epicardial Ablation Procedures
Many of the tachycardias described above can sometimes arise from the outer layers of heart muscle. Accordingly, it may not be possible to ablate these “epicardial” tachycardias from inside the heart. A procedure recently developed allows the introduction of catheters percutaneously into the pericardial space. We have performed this procedure and utilize it when indicated, that is when epicardial tissue is likely to be responsible for a given tachycardia. Indications for an epicardial approach include previous failure to ablate combined with evidence suggesting that the reason for failure is related to the presence of an epicardial source.
