IMPLANTABLE CARDIOVERTER DEFIBRILLATOR IS THE PREFERRED THERAPY FOR VENTRICULAR TACHYCARDIA COMPLICATING CORRECTED TETRALOGY OF FALLOT
D.L. Walters, M.L. Masterson, P. Pohlner, N. Twidale.
The Prince Charles Hospital, Brisbane, Queensland.
Late ventricular tachycardia (VT) is a feared complication after surgical repair of tetralogy of Fallot (TOF). As the implantable cardioverter defibrillator (ICD) has dramatically changed the management of VT in other patient groups over the last decade, we examined the role of ICD versus traditional therapy in a cohort of patients (pts) who developed VT after TOF repair using a transventriculotomy approach.
Method: Among approximately 400 TOF repair pts followed in our centre, 8 pts (7 male, 1 female) with a mean age of 26 years (range 17-39) developed VT 1 month to 30 years after surgery. TOF surgery was performed at a mean age of 11 years (range 2-19) using a transventricular approach. After TOF surgery, 5 of the pts required re-operation with pulmonary allografting and/or right ventricular outflow tract (RVOT) repair for pulmonary incompetence (PI) and 1 other pt had VSD closure.
Results: When VT developed, 4 pts presented with palpitations (mean VT cycle length 264ms [range 236-310]), but 4 other pts were resuscitated from cardiac arrest. Before electrophysiology study (EPS) was performed, baseline ECG abnormalities included right bundle branch block (8) and the mean QRS duration was 167ms (range 138-194). Echocardiographic and cardiac catheter abnormalities included right ventricular dilation (5), pulmonary stenosis (5) and significant PI (6), but left ventricular function was preserved in all pts. Among 7 pts who had inducible monomorphic VT at EPS, the mean cycle length was 269ms (range 240-310). Suppression of VT with antiarrhythmic drugs was attempted in 7 pts, but was unsuccessful in 6 and the other pt developed toxicity. Of 2 pts who were deemed suitable for attempted RFA, 1 had VT successfully ablated in the RVOT. ICD was implanted in 6 pts, while the 1 non-inducible pt declined therapy. During a mean follow-up of 3.7 years, 1 patient died of a non-cardiac cause and 2 of the ICD pts have had appropriate successful ICD shocks.
Conclusions: (1) VT is an uncommon but potentially lethal complication after TOF repair using a ventriculotomy approach. (2) ICD appears to be the preferred treatment option for most patients with VT following TOF repair and clinical outcome is similar to other ICD treated groups.
