Sustained Ventricular Tachycardia Associated With Corrective Valve Surgery

Abstract

Background-The causes of sustained monomorphic ventricular tachycardia (VT) after cardiac valve surgeries have not been studied extensively, although bundle-branch reentry has been reported. Methods and Results-Records of 496 patients referred for electrophysiology study and catheter ablation of recurrent VT were reviewed. Twenty patients (4%) had VT after aortic or mitral valve surgery in the absence of known myocardial infarction. The median age was 53 years, and the median ejection fraction was 45%. In 4 patients, VT occurred early after surgery, and electrophysiology study was performed 3 to 10 days later. In the remaining patients, electrophysiology study was performed a median of 12 years (interquartile range 5 to 15 years) after surgery. Sustained VT was inducible in 17 patients. VT was attributed to scar-related reentry in 14 patients (70%) and to bundle-branch reentry in 2 (10%).Multiple VTs were present in 9 of 14 patients with scar-related reentry. A total of 42 induced VTs were targeted for ablation. Of the 14 patients with scar-related reentry, 9 (64%) had periannular scar, and 10 (71%) had an identifiable endocardial circuit isthmus. Ablation abolished 41 (98%) of the 42 targeted VTs. At a median follow-up of 2.1 years, 3 deaths occurred 8 to 14 months after ablation. One patient with incessant VT early after valve surgery suffered a stroke with residual hemianopsia. Of the 20 patients, 3 required repeat ablation after recurrence, and 2 of these who were not inducible during electrophysiology study had clinical recurrence that necessitated ablation. Conclusions-Sustained VT after valve surgery appears to be bimodal in presentation, occurring either early after surgery or years later. In this referral population, reentry in a region of scar is more common than bundle-branch reentry. Catheter ablation can be successful.

Perivalvular Fibrosis and Monomorphic Ventricular Tachycardia

“…Of note, 12 of the 16 patients who underwent ablation late after surgery because of VT in the present report already had an implantable cardioverterdefibrillator in place for a median of 4.5 years, presumably for a documented arrhythmia episode in most. 12 Nevertheless, a distinction between early, Ͻ1 month, and late, Ͼ1 to 20 years, is valid and somewhat similar to the bimodal distribution of VT after myocardial infarction. The distinction also is supported by the observed differences noted in the electrophysiology laboratory between the 2 patient groups.…”

“…In this issue of Circulation, the report by Eckart and colleagues 12 answers that charge. Six years of clinical experience with VT ablation resulted in the identification of 20 patients who developed VT after prior cardiac valve surgery and underwent catheter ablative therapy.…”

“…12 Nearly two thirds of the patients with reentrant VT showed endocardial scar and a VT origin in a perivalvular distribution. Even more remarkable was the fact that in 8 of the 9 patients with perivalvular scar, the scar surrounded the valve replaced at the time of surgery.…”

“…Importantly, the outcome reported with VT catheter ablation was excellent with respect to both VT control and risk. 12 Caution should be applied, however, in assuming that these results can be duplicated beyond very experienced centers. Catheter entrapment in disk valves, resulting in acute valve dysfunction, and disruption of calcific porcine valves, resulting in serious embolic phenomena, must be recognized as potential life-threatening risks with catheter ablation in this setting.…”

“…12 Although a quantitative assessment of scar burden was not provided, patients demonstrated areas of scarring as indicated by the confluent areas of recorded low-amplitude bipolar electrogram voltage. For 14 of the 17 patients who presented with VT late after surgery, the authors also indicate that a scar-related reentrant mechanism was suggested by the response to stimulation during VT.…”