Introduction: The effects of general anesthesia (GA) on the inducibility and hemodynamics of ventricular tachycardia (VT) are not clear.
Methods: Studies were performed in 40 consecutive pts with prior VT who were undergoing radiofrequency ablation (RFA) {age 64±15; LVEF 36±13%; 50% Ischemic (ICMP)}. Pts underwent non invasive (NI) programmed stimulation (PS) using their ICD while awake. After induction of GA and prior to RFA, they underwent invasive RV programmed stimulation (IPS). Endpoint for PS was induction of sustained monomorphic VT (SMVT).
Results: In 4 pts (10%) no SMVT was inducible before or after GA. Of the 36 inducible pts pre-GA, 6 (16%) were not inducible after GA (p=0.03). Of the 30 inducible pts before and after GA , 17 (57%) needed a more aggressive PS to induce VT after GA.
In 20/30 (67%), the same VT was induced before and after GA and in 10/30 (33%) a different VT was induced after GA. GA more frequently rendered VT not inducible or changed inducible VT morphology in ICMP pts (12/19, 63%) compared to NICMP (4/17, 24%; p=0.02). Other baseline characteristics were not predictive of change in inducibility after GA. After GA, 24/30 (80%) pts received
pharmacologic hemodynamic support. In 12/ 30 (40%) pts, VT was hemodynamically stable before and after GA. In 14/30 (47%) pts, VTs were hemodynamically unstable before and after GA. Only in 4/30 pts (13%) were VTs stable before and unstable after GA (2 with the same QRS morphology and 2 with a different QRS morphology). Type of anesthesia agent did not predict VT stability. There were no complications associated with NIPS or IPS after GA.
Conclusion: This prospective study shows that inducibility of VT does not seem to be impaired by GA for the majority of patients with structural heart disease. In patients with ICMP, NIPS should be considered prior to initiation of GA if confirmation of inducible VT is desirable. Adjunctive hemodynamic support during GA, does not significantly alter stability of VT.
