Radiofrequency catheter ablation (RFCA) is an effective treatment strategy for patients with symptomatic premature ventricular complexes (PVCs). Adequate anesthesia is important for performing RFCA to ensure a comfortable, safe, and successful procedure. However, the sedation strategy employed must balance these safety goals with the need to induce and target the arrhythmia in question. General anesthesia (GA) may be helpful in some patients such as those with pulmonary comorbidities such as severe obstructive sleep apnea, or for anticipated longer or uncomfortable procedures (e.g., epicardial ablation). However, GA and deep sedation may result in the suppression of VAs, limiting the ability to perform activation mapping and assessing endpoints, possibly affecting procedural outcomes [1].

In this issue of the Journal of Interventional Cardiac Electrophysiology, Kazawa et. al. [2] present results of an observational, single-center, retrospective analysis reporting outcomes in 108 consecutive patients who underwent endocardial PVC ablation under either GA (82 patients) or local anesthesia with or without minimal sedation (LA; 26 patients). The COVID-19 pandemic allowed for a natural experiment at their institution where PVC ablations had previously been performed under GA before being required to be performed under LA due to logistic reasons. Patients in each group were well-balanced in their clinical characteristics and in PVC burden and morphologies. PVC burden measured at two time points at the beginning of the case before and after anesthesia administration but before catheter insertion was also similar between the two groups. During PVC mapping, however, activation mapping was performed significantly more often in the LA group compared to the GA group (77% vs 26%, p < 0.001), implying that later in the case PVC burden decreased in the GA group compared to the LA group, though this difference was not quantified. Acute ablation success, defined as the complete absence of the targeted PVCs after the last radiofrequency application to the end of the recording period, was significantly higher in the LA group than in the GA group (85% vs 50%, p < 0.01). Similarly, medium-term success, defined as ≥ 80% reduction in PVC burden on 24-h Holter monitoring without antiarrhythmic drugs, was also higher in the LA group (89% vs 66%, p = 0.027). Furthermore, the use of LA was found to be an important independent predictor for acute procedural success after multivariate analysis. Procedural time, fluoroscopy time, complication rate, and length of stay were not significantly different between both groups. Interestingly, total RF time was lower in the LA group (6.2 ± 4 min vs 9.8 ± 4 min, p = 0.003).

The authors postulate that the lower success rate in the GA group may be explained by GA-induced PVC suppression during the procedure. PVC suppression might affect outcomes in several different ways. During PVC ablation, activation mapping to identify the earliest site of activation is the gold standard strategy. Suppression of PVCs with GA results in an increased reliance on pace mapping (PM) techniques. While PM techniques have been demonstrated to be useful in mapping VAs, this strategy has important limitations including capture of remote tissue, coupling interval-dependent QRS morphology changes, and poor PM correlations with intramural sites of origin with multiple exit sites [3, 4]. Additionally, the presence of a higher intraprocedural PVC burden in the LA group resulted in a more definitive endpoint to guide ablation and procedural termination. Unguided by the intraprocedural suppression of PVCs in response to ablation, the decision to terminate the procedure was guided by more nebulous endpoints in the GA group.

The study has several important limitations. First, the sample size was relatively small. Second, the dose of sevoflurane in minimum alveolar concentration and the depth of anesthesia measured by the Bispectral index (BIS) were not reported. Including this information would have offered more insight into the effect of GA and PVC suppression. Additionally, while the purported mechanism of the increased reliance on PM over activation mapping in the GA group was due to a decrease in the intraprocedural PVC burden, this was not quantified.

In addition to minimizing sedation, the following approaches can be implemented to maximize ablation success in patients with low PVC burden:

  1. 1.

    Discontinue antiarrhythmic agents, beta-blockers, and calcium channel blockers for at least 5 half-lives before the procedure.

  2. 2.

    Review ambulatory Holter and event monitors to assess for diurnal variation in PVC burden to facilitate scheduling of procedure time accordingly.

  3. 3.

    Infusion of isoproterenol, epinephrine, aminophylline, phenylephrine, and calcium chloride alongside rapid atrial and ventricular pacing.

  4. 4.

    Attempt to perform activation mapping using multielectrode catheters [5] in conjunction with new mapping algorithms, such as pattern matching filter and parallel mapping.

  5. 5.

    Perform pace mapping with automatic algorithms, such as PASO and AutoMap Score Threshold.

We applaud the authors for sharing their experience describing the efficacy and safety of LA versus GA for PVC ablation demonstrating the superiority of LA over GA with regard to both short- and medium-term efficacy. While LA inevitably results in a more uncomfortable patient procedural experience, we at our institution have always favored LA over GA for PVC ablations and the results of this study support our anecdotal experience. While not examined in the current study, the cost implications including anesthesia care duration with LA versus GA should also be considered [6]. Although the present study has several limitations, the authors provide valuable data in support of multisociety guidelines which recommend avoiding deeper levels of sedation during PVC ablation.