Site Localization and Characterization of Pain During Radiofrequency Ablation of the Pulmonary Veins

Patient experience of very high power short duration radiofrequency ablation for atrial fibrillation under mild conscious sedation

BACKGROUND

Very high power short duration (vHPSD) radiofrequency ablation (RFA) may reduce ablation times and improve patient tolerability, permitting pulmonary vein isolation (PVI) under mild conscious sedation (mCS) and promoting same day discharge (SDD).

METHODS

First, a retrospective feasibility study was performed at 2 tertiary cardiac centres in the UK. Consecutive cases of first-time PVI using vHPSD ablation with 90 W lesions for up to 4 s were compared against cases performed using standard RF (sRF) and cryoballoon (Cryo) therapy. Subsequently, a prospective study of patients who had vHPSD or Cryo exclusively under mCS was undertaken. Questionnaires based on Likert and visual analogue scales (VAS) were used to measure anxiety, discomfort and pain.

RESULTS

In total, 182 patients (59 vHPSD, 62 sRF and 61 Cryo) were included in the retrospective study, with 53 (90%) of vHPSD cases successfully performed under mCS. PVI ablation time in the vHPSD group (5.8 ± 1.7 min) was shorter than for sRF (16.5 ± 6.3 min, p < 0.001) and Cryo (17.5 ± 5.9 min, p < 0.001). Fifty-one vHPSD and 52 Cryo patients were included in the prospective study. PVI ablation time in the vHPSD group was shorter than for the Cryo group (6.4 ± 2.9 min vs 17.9 ± 5.7 min, p < 0.001), but overall procedure duration was longer (121 ± 39 min vs 95 ± 20 min, p < 0.001). There were no differences in the patient experience of anxiety, discomfort or pain. SDD rates were the same in both groups (61% vs 67%, p = 0.49).

CONCLUSIONS

vHPSD RFA for PVI can be performed under mCS to achieve SDD rates comparable to cryoablation, without compromising patient experience.

Brain-based measures of nociception during general anesthesia with remifentanil: A randomized controlled trial

BACKGROUND

Catheter radiofrequency (RF) ablation for cardiac arrhythmias is a painful procedure. Prior work using functional near-infrared spectroscopy (fNIRS) in patients under general anesthesia has indicated that ablation results in activity in pain-related cortical regions, presumably due to inadequate blockade of afferent nociceptors originating within the cardiac system. Having an objective brain-based measure for nociception and analgesia may in the future allow for enhanced analgesic control during surgical procedures. Hence, the primary aim of this study is to demonstrate that the administration of remifentanil, an opioid widely used during surgery, can attenuate the fNIRS cortical responses to cardiac ablation.

METHODS AND FINDINGS

We investigated the effects of continuous remifentanil on cortical hemodynamics during cardiac ablation under anesthesia. In a randomized, double-blinded, placebo (PL)-controlled trial, we examined 32 pediatric patients (mean age of 15.8 years,16 females) undergoing catheter ablation for cardiac arrhythmias at the Cardiology Department of Boston Children's Hospital from October 2016 to March 2020; 9 received 0.9% NaCl, 12 received low-dose (LD) remifentanil (0.25 mcg/kg/min), and 11 received high-dose (HD) remifentanil (0.5 mcg/kg/min). The hemodynamic changes of primary somatosensory and prefrontal cortices were recorded during surgery using a continuous wave fNIRS system. The primary outcome measures were the changes in oxyhemoglobin concentration (NadirHbO, i.e., lowest oxyhemoglobin concentration and PeakHbO, i.e., peak change and area under the curve) of medial frontopolar cortex (mFPC), lateral prefrontal cortex (lPFC) and primary somatosensory cortex (S1) to ablation in PL versus remifentanil groups. Secondary measures included the fNIRS response to an auditory control condition. The data analysis was performed on an intention-to-treat (ITT) basis. Remifentanil group (dosage subgroups combined) was compared with PL, and a post hoc analysis was performed to identify dose effects. There were no adverse events. The groups were comparable in age, sex, and number of ablations. Results comparing remifentanil versus PL show that PL group exhibit greater NadirHbO in inferior mFPC (mean difference (MD) = 1.229, 95% confidence interval [CI] = 0.334, 2.124, p < 0.001) and superior mFPC (MD = 1.206, 95% CI = 0.303, 2.109, p = 0.001) and greater PeakHbO in inferior mFPC (MD = -1.138, 95% CI = -2.062, -0.214, p = 0.002) and superior mFPC (MD = -0.999, 95% CI = -1.961, -0.036, p = 0.008) in response to ablation. S1 activation from ablation was greatest in PL, then LD, and HD groups, but failed to reach significance, whereas lPFC activation to ablation was similar in all groups. Ablation versus auditory stimuli resulted in higher PeakHbO in inferior mFPC (MD = 0.053, 95% CI = 0.004, 0.101, p = 0.004) and superior mFPC (MD = 0.052, 95% CI = 0.013, 0.091, p < 0.001) and higher NadirHbO in posterior superior S1 (Pos. SS1; MD = -0.342, 95% CI = -0.680, -0.004, p = 0.007) during ablation of all patients. Remifentanil group had smaller NadirHbO in inferior mFPC (MD = 0.098, 95% CI = 0.009, 0.130, p = 0.003) and superior mFPC (MD = 0.096, 95% CI = 0.008, 0.116, p = 0.003) and smaller PeakHbO in superior mFPC (MD = -0.092, 95% CI = -0.680, -0.004, p = 0.007) during both the stimuli. Study limitations were small sample size, motion from surgery, indirect measure of nociception, and shallow penetration depth of fNIRS only allowing access to superficial cortical layers.

CONCLUSIONS

We observed cortical activity related to nociception during cardiac ablation under general anesthesia with remifentanil. It highlights the potential of fNIRS to provide an objective pain measure in unconscious patients, where cortical-based measures may be more accurate than current evaluation methods. Future research may expand on this application to produce a real-time indication of pain that will aid clinicians in providing immediate and adequate pain treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02703090.

The effectiveness of hypnotic analgesia in the management of procedural pain in minimally invasive procedures: A systematic review and meta-analysis

INTRODUCTION

Patients undergoing minimally invasive procedures under a light conscious sedation perceive pain and anxiety. Hypnosis used together with analgesics has been investigated in numerous studies.

AIMS AND METHODS

To assess the effectiveness of hypnotic analgesia in management of pain, anxiety, analgesic consumption, procedure length and adverse events in adults undergoing minimally invasive procedures. Clinical controlled trials in which hypnosis was used together with pharmacological analgesia compared to pharmacological analgesia alone during invasive procedures were included. Seven databases were searched. The methodological quality of the studies was assessed by two reviewers using a standardised instrument for critical appraisal from Joanna Briggs Institute, 'Meta-Analysis of statistics assessment and review Instrument'. Meta-analyses using the review manager version 5.3 software were conducted on procedure length and adverse events. Results for pain, anxiety and analgesics were synthesised in narrative summaries. Conduction of the review adheres to the PRISMA checklist.

RESULTS

Ten studies comprising 1,365 participants were included. A reduction in the consumption of pain medication was found between 21%-86% without aggravating pain intensity and anxiety. In few studies, significant reduction in pain intensity and anxiety was found. Meta-analysis including seven studies revealed a small beneficial effect on reducing procedure length. A meta-analysis on adverse events showed no significant reduction. Statistical heterogeneity was found among the studies included.

CONCLUSION

For patients undergoing invasive procedures, hypnotic analgesia was effective in reducing consumption of analgesics. Only a slight effect was, however, found on experienced anxiety and pain intensity. It did not prolong the procedure and was safe to provide.

RELEVANCE TO CLINICAL PRACTICE

Hypnosis is recommended as pain management for adults during invasive procedures. A reduced consumption of pain medication potentially has a major impact on monitoring and observation of patients following the procedure, thus improving patient safety and reducing resource consumption.

Capturing Pain in the Cortex during General Anesthesia: Near Infrared Spectroscopy Measures in Patients Undergoing Catheter Ablation of Arrhythmias

The predictability of pain makes surgery an ideal model for the study of pain and the development of strategies for analgesia and reduction of perioperative pain. As functional near-infrared spectroscopy reproduces the known functional magnetic resonance imaging activations in response to a painful stimulus, we evaluated the feasibility of functional near-infrared spectroscopy to measure cortical responses to noxious stimulation during general anesthesia. A multichannel continuous wave near-infrared imager was used to measure somatosensory and frontal cortical activation in patients undergoing catheter ablation of arrhythmias under general anesthesia. Anesthetic technique was standardized and intraoperative NIRS signals recorded continuously with markers placed in the data set for the timing and duration of each cardiac ablation event. Frontal cortical signals only were suitable for analysis in five of eight patients studied (mean age 14 ± 1 years, weight 66.7 ± 17.6 kg, 2 males). Thirty ablative lesions were recorded for the five patients. Radiofrequency or cryoablation was temporally associated with a hemodynamic response function in the frontal cortex characterized by a significant decrease in oxyhemoglobin concentration (paired t-test, p<0.05) with the nadir occurring in the period 4 to 6 seconds after application of the ablative lesion. Cortical signals produced by catheter ablation of arrhythmias in patients under general anesthesia mirrored those seen with noxious stimulation in awake, healthy volunteers, during sedation for colonoscopy, and functional Magnetic Resonance Imaging activations in response to pain. This study demonstrates the feasibility and potential utility of functional near-infrared spectroscopy as an objective measure of cortical activation under general anesthesia.

Site localization of painful lesions during radiofrequency ablation of pulmonary veins using circular multi-electrode catheters

PURPOSE

Previous data showed that pain sensation was common during pulmonary vein isolation (PVI) using an 8-mm radiofrequency (RF) ablation catheter. Pain was more common in the left pulmonary veins (PVs). We characterized the location of pain during PVI using circular multi-electrode ablation catheters.

METHODS

Included are all consecutive patients with atrial fibrillation (AF) who underwent PVI using the phased RF PVAC® catheter (Medtronic) or the irrigated nMARQ™ catheter (Biosense Webster) under conscious sedation between July 2011 and March 2015. Site of pain reaction was marked for each patient.

RESULTS

A total of 251 patients (141 PVAC®, 110 nMARQ™) were studied; 214 (85 %) had at least one lesion associated with pain. Gender (r = 0.084, p = 0.186), type of AF (r = 0.048, p = 0.452), age (r = 0.078, p = 0.216), and repeat procedure (r = 0.018, p = 0.78) were not correlated with pain. There was no association between site of pain and catheter type; only 33% of the painful PVs were also the largest ones (p = 0.5, kappa = 0.03, R = -0.083). One-year freedom from AF was similar for patients with and without painful PVs (p = 0.6). The distribution of pain was as follows: 126 (59%) left superior PV (LSPV), 28 (13%) left inferior, 28 (13%) all PVs, 12 (5.6%) right superior, 12 (5.6%) right inferior, 18 (8.4%) left common, and 2 (0.9%) right common PV.

CONCLUSIONS

PVI using multi-electrode catheters more commonly caused pain sensation in LSPV. There was no influence of catheter type or PV size on pain localization. Our findings, which are similar to those using an 8-mm ablation catheter, imply that location of pain is not catheter dependent but rather a reflection of autonomic physiology.

Headache during cryoballoon ablation for atrial fibrillation

AIMS

Headache has been reported to occur during cryoballoon ablation for atrial fibrillation (AF). No study has systematically analysed this phenomenon.

METHODS AND RESULTS

Twenty consecutive patients with symptomatic AF underwent cryoballoon ablation without sedation. Headache was evaluated before, during, and after the first cryoapplication in every pulmonary vein (PV) using a visual representation of a head for location of the headache, a numerical rating scale (NRS) for measuring pain intensity and the short-form McGill pain questionnaire (MPQ) for qualitative analysis of pain. The order in which the PVs were ablated was randomized. Sixteen (80%) patients perceived mainly frontal headache during cryoablation. The overall NRS scores were significantly higher during (5.1 ± 1.7), compared with before (2.7 ± 1.4), and after (3.5 ± 2.2) a cryoapplication (P < 0.05). The NRS score was significantly higher during ablation of the first PV. The intensity of the perceived headache was not related to the temperature reached 150 s after initiation of a cryoapplication (P = 0.81). Of the MPQ, three sensory adjectives and one affective adjective averaged between scores 1 and 2, representing mild-to-moderate severity of pain.

CONCLUSION

The majority of patients treated by balloon cryoablation experienced headache during a cryoapplication. There was no correlation between the temperature reached during a cryoballoon freeze and the intensity of the headache. Cryoballoon ablation of the first PV was significantly more painful than the remaining PVs.

Premedication and preoperative information reduces pain intensity and increases satisfaction in patients undergoing ablation for atrial fibrillation. A randomised controlled study

BACKGROUND

Pain and discomfort are common during radiofrequency ablation (RFA) for atrial fibrillation.

AIMS

To compare and evaluate the effect of premedication, standardised preoperative information and preoperative anxiety on pain intensity, drug consumption and patients' satisfaction.

METHODS

Preoperative anxiety at baseline, pain intensity during RFA, and patient satisfaction after the procedure were measured in 3 random groups. Group A (n=20) received standard pain management, group B (n=20) received premedication and group C (n=20) received premedication and standardised preoperative information.

RESULTS

Patients in groups B and C experienced less pain intensity (p<0.001) and needed fewer anxiolytics (p=0.023) and analgesics (p=0.031) compared to group A. Patient satisfaction was higher in group C (p=0.005) compared to group A. Increased preoperative anxiety is related to elevated drug demand (p<0.05).

CONCLUSION

Premedication alone or combined with preoperative information reduces and higher preoperative anxiety increases pain intensity and drug consumption during RFA. Preoperative information improves patient satisfaction.

Visualisation during ablation of atrial fibrillation - stimulating the patient's own resources: Patients' experiences in relation to pain and anxiety during an intervention of visualisation

BACKGROUND

Going through ablation of atrial fibrillation can be accompanied by pain and discomfort when a light, conscious sedation is used. Visualisation has been shown to reduce the patients' perception of pain and anxiety during invasive procedures, when it is used together with the usual pain management.

PURPOSE

The purpose of this study was to investigate patients' experiences with visualisation in relation to pain and anxiety during an intervention consisting of visualisation, when undergoing ablation of atrial fibrillation.

METHODS

Qualitative interviews were conducted with 14 patients from a study population of a clinical controlled study with 147 patients. The transcribed interviews were analysed according to qualitative methodology of inductive content analysis.

FINDINGS

Four categories emerged from the interviews: 'approach to visualisation'; 'strategies of managing pain'; 'strategies of managing anxiety' and 'benefits of visualisation'. The transversal analyses revealed two overall themes which highlight the experiences of being guided in visualisation during ablation of atrial fibrillation: 'stimulation of the patients' own resources' and 'being satisfied without complete analgesia'

CONCLUSION

Visualisation used during ablation of atrial fibrillation was reported as a positive experience with no serious inconvenience: It seemed that visualisation did not produce complete analgesia but the patients expressed that it provided some pain relief and supported their individual strategies in managing pain and anxiety. Our findings indicate that visualisation for acute pain during ablation of atrial fibrillation was associated not only with a decrease in experience of pain but also with high levels of treatment satisfaction and other non-pain-related benefits.