Background: Although patients with left ventricular assist devices (LVADs) often experience ventricular tachycardia (VT), little is known about relationship between timing and mechanism of VTs.
Objective: To assess relationship between timing and mechanisms of VTs in patients with LVADs.
Methods: The mechanism and origin of 65 VTs were defined during 27 ablation procedures in 20 consecutive patients with LVAD and frequent, drug-refractory VT (mean age of 55±12 years, LV ejection fraction; 16±6 %) at two tertiary care centers.
Results: Cardiomyopathy was ischemic in 8 and non-ischemic in 12. Median time to emergence of VT was 130 (25th-75th percentile, 5 - 245) days with VT occurring within 1 week in 6, 1 week to 6 months in 5 and later than 6 months in 9. Mechanisms of VT were peri-cannula reentry (17), Purkinje related (5), and scar-related reentry (43). All 3 patients with Purkinje related VT had both peri-cannula and scar related VT. In patients without a prior history of VT, peri-cannula VT was only observed > 6 months after LVAD placement (Figure). All 6 patients with VT within 7 days after LVAD placement had pre LVAD history of VT. Of 17 peri-cannula VTs, 12 (71%) were abolished by endocardial ablation and 5 remained inducible (in 2 VTs despite transcoronary ethanol ablation). In contrast, endocardial ablation abolished all Purkinje related VTs and 88% of scar related VTs. There were no major procedural complications. One patient who had recurrent VT and severe heart failure died 4 days after ablation.
Conclusion: The mechanisms of VT likely to be encountered vary with the time from LVAD placement. Peri-cannula VTs tend to emerge late and are often difficult to ablate.