Dexmedetomidine Sedation for Paroxysmal Supraventricular Tachycardia Ablation Is Not Associated With Alteration of Arrhythmia Inducibility

Electrophysiological differences of randomized deep sedation with dexmedetomidine versus propofol

BACKGROUND

Dexmedetomidine and propofol are common sedatives in intensive care units and for interventional procedures. Both may compromise sinus node function and atrioventricular conduction. The objective of this prospective, randomized study is to compare the effect of dexmedetomidine with propofol on sinus node function and atrioventricular conduction.

METHODS

In a tertiary care center in Switzerland we included from September 2019 to October 2020 160 patients (65 ± 11 years old; 32% female) undergoing first ablation for atrial fibrillation by cryoballoon ablation or by radiofrequency ablation. Patients were randomly assigned to deep sedation with dexmedetomidine (DEX group) versus propofol (PRO group). A standard electrophysiological study was performed after pulmonary vein isolation with the patients still deeply sedated and hemodynamically stable.

RESULTS

Eighty patients each were randomized to the DEX and PRO group. DEX group patients had higher baseline sinus cycle length (1022 vs. 1138 ms; p = 0.003) and longer sinus node recovery time (SNRT400; 1597 vs. 1412 ms; p = 0.042). However, both corrected SNRT and normalized SNRT did not differ. DEX group patients had longer PR interval (207 vs. 186 ms; p = 0.002) and AH interval (111 vs. 95 ms, p = 0.008), longer Wenckebach cycle length of the atrioventricular node (512 vs. 456 ms; p = 0.005), and longer atrioventricular node effective refractory period (390 vs. 344 ms; p = 0.009). QRS width and HV interval were not different. An arrhythmia, mainly atrial fibrillation, was induced in 33 patients during the electrophysiological study, without differences among groups (20% vs. 15%, p = 0.533).

CONCLUSIONS

Dexmedetomidine has a more pronounced slowing effect on sinus rate and suprahissian AV conduction than propofol, but not on infrahissian AV conduction and ventricular repolarization. These differences need to be taken into account when using these sedatives.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT03844841, 19/02/2019.

Management of anesthesia for procedures in the cardiac electrophysiology laboratory

The complexity of cardiac electrophysiology procedures has increased significantly during the past 3 decades. Anesthesia requirements of these procedures can differ on the basis of patient- and procedure-specific factors. This manuscript outlines various anesthesia strategies for cardiac implantable electronic devices and electrophysiology procedures, including preprocedural, procedural, and postprocedural management. A team-based approach with collaboration between cardiac electrophysiologists and anesthesiologists is required with careful preprocedural and intraprocedural planning. Given the recent advances in electrophysiology, there is a need for specialized cardiac electrophysiology anesthesia care to improve the efficacy and safety of the procedures.

Impact of dexmedetomidine on electrophysiological properties and arrhythmia inducibility in adult patients referred for reentrant supraventricular tachycardia ablation

BACKGROUND

Drugs used for sedation/analgesia may affect the basic cardiac electrophysiologic properties or even supraventricular tachycardia (SVT) inducibility. Dexmedetomidine (DEX) is a selective alpha-2 adrenergic agonist with sedative and analgesic properties. A comprehensive evaluation on use of DEX for reentrant SVT ablation in adults is lacking. The present study aims to systematically assess the impact of DEX on cardiac electrophysiology and SVT inducibility.

METHODS

Hemodynamic, electrocardiographic, and electrophysiological parameters and SVT inducibility were assessed before and after DEX infusion in patients scheduled for ablation of reentrant SVT.

RESULTS

The population of this prospective observational study included 55 patients (mean age of 58.7 ± 14 years, 29 males [52.7%]). A decrease in systolic and diastolic blood pressure and in heart rate was observed after DEX infusion (p = 0.001 for all). DEX increased corrected sinus node refractory time, atrial effective refractory period, AH interval, AV Wenckebach cycle length, and AV node effective refractory period without affecting the His-Purkinje conduction or ventricular myocardium refractoriness. No AV blocks or sinus arrests occurred during DEX infusion. Globally, there was no difference in SVT inducibility in basal condition or after DEX infusion (46/55 [83.6%] vs. 43/55 [78.1%] patients; p = 0.55), without a difference in isoprenaline use (p = 1.0). In 4 (7.3%) cases, the SVT was inducible only after DEX infusion. In 34.5% of cases, DEX infusion unmasked the presence of an obstructive sleeping respiratory pattern, represented mainly by snoring.

CONCLUSIONS

DEX depresses sinus node function and prolongs atrioventricular refractoriness without significantly affecting the rate of SVT inducibility in patients scheduled for reentrant SVT ablation.

Perioperative Maternal-Fetal Outcomes in the Setting of Minimally Invasive Fetal Therapy for Complex Monochorionic Pregnancies with Monitored Anesthesia Care

INTRODUCTION

Fetoscopic selective laser photocoagulation (FSLPC) and selective cord occlusion with radiofrequency ablation (RFA) can improve fetal outcomes when vascular anastomoses between fetuses cause twin-to-twin transfusion syndrome (TTTS) or selective fetal growth restriction (sFGR) in multiple gestation pregnancies with monochorionic placentation. This study analyzed perioperative maternal-fetal complications and anesthetic management in a high-volume fetal therapy center over a 4-year period.

METHODS

Included patients received MAC for minimally invasive fetal procedures for complex multiple gestation pregnancies between January 1, 2015, and September 20, 2019. Maternal and fetal complications, intraoperative maternal hemodynamics, medication usage, and reasons for conversion to general anesthesia, if applicable, were analyzed.

RESULTS

A total of 203 (59%) patients underwent FSLPC and 141 (41%) had RFA. Four patients (2%; rate 95% CI: 0.00039, 0.03901) undergoing FSLPC had conversion to general anesthesia. No conversions to general anesthesia occurred in the RFA group. The incidence of maternal complications was higher in those who underwent FSLPC. No aspiration or postoperative pneumonia events were observed. Medication usage was similar in FSLPC and RFA groups.

CONCLUSION

A low rate of conversion to general anesthesia and no serious adverse maternal events were observed in patients receiving MAC.

Anesthetic Considerations in the Electrophysiology Laboratory: A Comprehensive Review

Catheter ablation procedures for arrhythmias or implantation and/or extraction of cardiac pacemakers can present many clinical challenges. It is imperative that there is clear communication and understanding between the anesthesiologist and electrophysiologist during the perioperative period regarding the mode of ventilation, hemodynamic considerations, and various procedural complications. This article provides a comprehensive narrative review of the anesthetic techniques and considerations for catheter ablation procedures, ventilatory modes using techniques such as high-frequency jet ventilation, and strategies such as esophageal deviation and luminal temperature monitoring to decrease the risk of esophageal injury during catheter ablation. Various hemodynamic considerations, such as the intraprocedural triaging of cardiac tamponade and fluid administration during catheter ablation, also are discussed. Finally, this review briefly highlights the early research findings on pulse-field ablation, a new and evolving ablation modality.

Effects of Dexmedetomidine on Basic Cardiac Electrophysiology in Adults; a Descriptive Review and a Prospective Case Study

Dexmedetomidine (DEX) is a commonly used sedative agent with no or minimal effects on breathing. DEX may also be beneficial in myocardial protection. Since the mechanisms of cardiac effects are not well known, we carried out a descriptive review and examined the effects of DEX on myocardial electrical conduction in a prospective and controlled manner. For the review, clinical studies exploring DEX in myocardial protection published between 2020-2022 were explored. A case study included 11 consecutive patients at a median (range) age of 48 (38-59), scheduled for elective radiofrequency ablation of paroxysmal atrial fibrillation. A bolus dose of DEX 1 µg/kg given in 15 min was followed by a continuous infusion of 0.2-0.7 µg/kg/h. Direct intracardiac electrophysiologic measurements, hemodynamics and oxygenation were measured before and after the DEX bolus. Experimental studies show that DEX protects the heart both via stabilizing cardiac electrophysiology and reducing apoptosis and autophagy after cell injury. The clinical evidence shows that DEX provides cardiac protection during different surgeries. In a clinical study, DEX increased the corrected sinus node recovery time, prolongated the atrioventricular (AV) nodal refractory period and cycle length producing AV nodal Wenckebach retrograde conduction block. DEX has a putative role in organ protection against hypoxic, oxidative and reperfusion injury. DEX slows down the firing of the sinus node and prolongs AV refractoriness.

The Practice of Deep Sedation in Electrophysiology and Cardiac Pacing Laboratories: Results of an Italian Survey Promoted by the AIAC (Italian Association of Arrhythmology and Cardiac Pacing)

The aim of this survey, which was open to all Italian cardiologists involved in arrhythmia, was to assess common practice regarding sedation and analgesia in interventional electrophysiology procedures in Italy. The survey consisted of 28 questions regarding the approach to sedation used for elective direct-current cardioversion (DCC), subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation, atrial fibrillation (AF) ablation, ventricular tachycardia (VT) ablation, and transvenous lead extraction procedures. A total of 105 cardiologists from 92 Italian centres took part in the survey. The rate of centres where DCC, S-ICD implantation, AF ablation, VT ablation and lead extraction procedures were performed without anaesthesiologic assistance was 60.9%, 23.6%, 51.2%, 37.3%, and 66.7%, respectively. When these procedures were performed without anaesthesiologic assistance, the drugs (in addition to local anaesthetics) commonly administered were benzodiazepines (from 64.3% to 79.6%), opioids (from 74.4% to 88.1%), and general anaesthetics (from 7.1% to 30.4%). Twenty-three (21.9%) of the 105 cardiologists declared that they routinely administered propofol, without the supervision of an anaesthesiologist, in at least one of the above-mentioned procedures. In current Italian clinical practice, there is a lack of uniformity in the sedation/analgesia approach used in interventional electrophysiology procedures.

Comparison of Outcomes of Pediatric Catheter Ablation by Anesthesia Strategy: A Report From the NCDR IMPACT Registry

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Induction and maintenance of procedural sedation in adults: focus on remimazolam injection

Introduction: Procedural sedation (PS) is a humane way to help patients get through painful medical procedures by the administration of sedative drugs combined with analgesics. However, each of the currently used medications has certain shortcomings, urging the search for a new drug. Remimazolam, a novel benzodiazepine, is an ultra-short-acting hypnotic agent invented out of the 'soft drug' development.Areas covered: This presented review provides an overview of the drugs used in clinical practice for the induction and maintenance of procedural sedation in adults, focusing on the newly investigated benzodiazepine remimazolam. Literature search was conducted using the MEDLINE and ClinicalTrial.gov databases from January 2007 to December 2020.Expert opinion: Based on the reported clinical trials so far, remimazolam has demonstrated its effectiveness and safety with promising properties including rapid onset, short duration of action, predictable and consistent recovery profile, metabolism almost unaffected by liver or renal function, with non or minimal cardiorespiratory depression, and availability with a reversal drug. With marketing approval received recently, remimazolam is expected to have a place in the practice for procedural sedation in the near future if its efficacy and safety are further confirmed by more clinical trials and post-market analyses.

Outcomes of deep sedation for catheter ablation of paroxysmal supraventricular tachycardia, with adaptive servo ventilation

BACKGROUND

Catheter ablation for paroxysmal supraventricular tachycardia (PSVT) is an established treatment, but the effect of deep sedation on PSVT inducibility remains unclear.

AIM

We sought to examine PSVT inducibility and outcomes of catheter ablation under deep sedation using adaptive servo ventilation (ASV).

METHODS

We retrospectively evaluated consecutive patients who underwent catheter ablation for PSVT under deep sedation (Propofol + Dexmedetomidine) with use of ASV. Anesthetic depth was controlled with BIS™ monitoring, and phenylephrine was administered to prevent anesthesia-induced hypotension. PSVT induction was attempted in all patients using extrastimuli at baseline, and after isoproterenol (ISP) infusion when necessary.

RESULTS

PSVT was successfully induced in 145 of 147 patients, although ISP infusion was required in the majority (89%). The PSVT was atrioventricular nodal reentrant tachycardia (AVNRT) in 77 (53%), atrioventricular reciprocating tachycardia (AVRT) in 51 (35%), and atrial tachycardia (AT) in 17 (12%). A higher ISP dose was required for AT compared to other PSVT (AVNRT: 0.06 (IQR 0.03-0.06) vs AVRT: 0.03 (0.02-0.06) vs AT: 0.06 (0.03-0.12) mg/h, P = .013). More than half (51%) of the patients developed hypotension requiring phenylephrine; these patients were older. Acute success was obtained in 99% (patients with AVNRT had endpoints with single echo on ISP in 46%). Long-term success rate was 136 of 144 (94%) (AVNRT 96%, AVRT 92%, and AT 93%). There were no complications related to deep sedation.

CONCLUSIONS

Deep sedation with use of ASV is a feasible anesthesia strategy for catheter ablation of PSVT with good long-term outcome. PSVT remains inducible if ISP is used.

Dexmedetomidine: What's New for Pediatrics? A Narrative Review

Over the past few years, despite the lack of approved pediatric labelling, dexmedetomidine’s (DEX) use has become more prevalent in pediatric clinical practice as well as in research trials. Its respiratory-sparing effects and bioavailability by various routes are only some of the valued features of DEX. In recent years the potential organ-protective effects of DEX, with the possibility for preserving neurocognitive function, has put it in the forefront of clinical and bench research. This comprehensive review focused on the pediatric literature but presents relevant, supporting adult and animal studies in order to detail the recent growing body of literature around the pharmacology, end-organ effects, organ-protective effects, alternative routes of administration, synergetic effects, and clinical applications, with considerations for the future.

Effects of anesthesia on cerebral blood flow, metabolism, and neuroprotection

Administration of anesthetic agents fundamentally shifts the responsibility for maintenance of homeostasis from the patient and their intrinsic physiological regulatory mechanisms to the anesthesiologist. Continuous delivery of oxygen and nutrients to the brain is necessary to prevent irreversible injury and arises from a complex series of regulatory mechanisms that ensure uninterrupted cerebral blood flow. Our understanding of these regulatory mechanisms and the effects of anesthetics on them has been driven by the tireless work of pioneers in the field. It is of paramount importance that the anesthesiologist shares this understanding. Herein, we will review the physiological determinants of cerebral blood flow and how delivery of anesthesia impacts these processes.