Abstract 3095: Sustained Ventricular Tachycardia Associated with Corrective Valve Surgery
Introduction: The causes of sustained monomorphic VT after cardiac valve surgeries have not been extensively studied, although bundle branch reentry has been described.
Methods and Results: Records of 496 patients referred for electrophysiologic study (EPS) and catheter ablation of recurrent VT from January 2000 to December 2005 were reviewed. A total of 20 patients (4%) had VT after valve surgery. All were male, median age of 53 years, (range, 34–76). Median LVEF was 45%. The surgical procedure was aortic valve replacement (n=13), mitral valve replacement (n=1), both mitral and aortic valve replacement (n=1) and mitral valve repair (n=5). No patient had clinical evidence of territorial infarction at the time of EPS. In 4 patients VT occurred early post-operatively and EPS was performed 3 to 10 days later. In the remaining cases EPS was a median of 12 years [IQR 5, 15] after surgery. Sustained monomorphic VT was inducible in 17 patients. A low voltage area consistent with scar was noted in 93% of the 15 patients that underwent electroanatomic mapping of the left ventricle. VTs were due to scar-related reentry in 14 (70.0%), bundle branch reentry in 2 (10.0%), and had a focal origin in 1 (5.0%). Multiple VTs were present in 9 of 14 patients with scar-related VT. A total of 42 induced VTs were targeted for ablation. The median induced tachycardia cycle length was 348msec (range 183– 660msec). Of the 14 patients with scar-related reentry, there was evidence of annular scar in 9 (64.3%) and an endocardial isthmus site was identified in 10 (71.4%) patients. The median number of ablations per case was 14 [IQR 4, 25]. Ablation abolished 41 (97.6%) of the induced VTs. One patient did not undergo ablation of a focal origin at the left bundle insertion because of pre-existing right bundle branch block. In those with scar-related VT, all patients were rendered non-inducible for clinical VT. One patient with incessant VT early after valve surgery suffered a stroke with residual hemianopsia.
Discussion: Sustained monomorphic VT following valve surgery is bimodal in presentation, either early after surgery or years later. Reentry in a region of scar is more common than bundle branch reentry. Etiology of scar regions is often not clear. Catheter ablation can be successful.