Muscle contractions and pain sensation using nanosecond pulse field ablation system under conscious sedation: first in man study

Abstract Background Pulse field ablation (PFA) is a novel nonthermal way to perform cardiac ablation. It is well documented that microsecond PFA could stimulate motor neurons, lead to muscle contraction and pain which usually need general anesthesia. Severe muscle contraction can result higher risk of perforation, instability and inadequate contact of catheter[1]. Additionally, general anesthesia increases the whole procedural time and is not achievable in all hospitals especially low-income regions. Nanosecond PFA could significantly reduce muscle contraction in our pre-clinical study and have the potential to perform under conscious sedation. Purpose The present study aims to evaluate the muscle contraction and pain sensation of atrial fibrillation (AF) ablation using nanosecond PFA under conscious sedation. Methods Eligible participants were diagnosed with symptomatic AF and had nonresponse or intolerance to at least 1 antiarrhythmic drug. The conscious sedation started using midazolam 1mg intravenous injection (iv) and tropisetron hydrochloride 5mg iv administered before the femoral vein puncture. Afterwards, infusion of fentanyl 3-4mg/kg/h was started. The infusion rate of fentanyl was increased to 6-10mg/kg/h after the transseptal puncture. Muscle contraction is measured by two physicians with their hands on the abdomen of the patient during the application of PFA. The grade of muscle contraction was classified into three levels: a. none; b. slight; c. severe. Visual analogue scale (VAS) consists of a 10 cm line, one side represents "no pain" and the other side represents "unbearable pain". Patients need to draw a vertical mark through the line to qualify the intensity of pain. Likert scale questionnaires are used to assess the individual feelings of the nanosecond PFA. Results A total of 16 AF patients (59.4 ± 12.7 years, 11/13 male) were enrolled in the study and 8 of the them were persistent AF (Figure 1). During the conscious sedation, all patients achieved 0 score of Richmond Agitation-Sedation Scale which means patients were in alert and calm status. Muscle contraction during PFA applications were recorded in all patients. Nanosecond PFA caused none, slight, and severe muscle contraction in 90%, 9%, and 1% applications. In the mean time, during the PFA application, the percentage of patients reporting VAS of 0-4, 5-8, and 9-10 score were 64.3%, 28.6%, and 7.1%, respectively. Ten patients (10/14, 71.4%) remembered everything of the procedure and 9 patients (9/14, 64.3%) said will definitely choose conscious sedation rather than general anesthesia. Additionally, all patients were very satisfied with the procedure (Figure 2). There was no three-dimensional model shift or procedure-related complication. Conclusion It is safe and feasible to perform nanosecond PFA under conscious sedation. All patients were very satisfied with the procedure and the muscle contraction and pain induced by nanosecond PFA were acceptable.