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.

Anaesthetic management of paediatric patients undergoing electrophysiology study and ablation for supraventricular tachycardia: A focused narrative review

Every year, 80,000-100,000 ablation procedures take place in the United States and approximately 1% of these involve paediatric patients. As the paediatric population undergoing catheter ablation to treat dysrhythmia is constantly growing, involvement of anaesthesiologists in the cardiac electrophysiology laboratory is simultaneously increasing. Compared with the adult population, paediatric patients need deeper sedation or general anaesthesia (GA) to guarantee motionlessness and preserve comfort. As a result, the anaesthesiologist working in this setting should keep in mind heart physiopathology as well as possible interactions between anaesthetic drugs and arrhythmia. In fact, drug-induced suppression of accessory pathways (APs) conduction capacity is a major concern for completing a successful electrophysiology study (EPS). Nevertheless, the literature on this topic is scarce and the optimal type of anaesthesia in EPS and ablation procedures in children is still controversial. Thus, the main goal of the present review is to collect the literature published so far on the effects on cardiac conduction tissue of the drugs commonly employed for sedation/GA in the cath lab for EPS and ablation procedures to treat supraventricular tachycardia in patients aged <18 years.

Focal Pulsed Field Ablation for Atrial Arrhythmias: Efficacy and Safety under Deep Sedation

Focal pulsed field ablation (PFA) is a novel technique for treating cardiac arrhythmias. It has demonstrated positive results in initial studies and has a good safety profile. In recent studies, PFA was often utilized for first-time pulmonary vein isolation (PVI) and was performed under general anesthesia. In our study, we assessed the feasibility, safety, acute procedural efficacy, and efficiency of focal PFA under deep sedation in patients, 80% of whom had undergone at least one left atrial ablation previously. We treated 30 patients (71 ± 7, 46% male) using the CENTAURI system for various atrial arrhythmias, including atrial fibrillation, typical and atypical atrial flutter, and focal atrial tachycardia. The average procedure and fluoroscopy times were 122 ± 43 min and 9 ± 7 min, respectively. A total of 83.33% of patients received additional line ablations beyond PVI, specifically targeting the posterior box and anterior mitral line. All ablations were successfully performed in deep sedation with only one major and one minor complication observed. The major complication was a vasospasm of the right coronary artery during ablation of the cavotricuspid isthmus, which was treated successfully with intracoronary nitroglycerin. All patients could be discharged in sinus rhythm. Moreover, adenosine appears effective in identifying dormant conduction in some patients after focal PFA. In conclusion, focal PFA is an effective approach for complex left atrial ablations under deep sedation, offering both high efficacy and efficiency with a reliable safety profile. Studies on long-term outcomes are needed.

Anesthetic Management In Electrophysiology Laboratory: A Multidisciplinary Review

Many clinical challenges have been encountered in electrophysiology laboratories (EP) while implanting intracardiac defibrillators for lethal arrhythmias, using pacemakers for bradyarrhythmias, placing pacemakers with multiple leads in patients with heart failure and cardiac ablation procedures. In this environment, anesthesiology plays a very critical role to ensure patients comfort, as well as maintains operator's convenience and facilitate management of undesired situations. EP laboratories are mostly used for diagnosis of certain heart diseases. Meanwhile, with the exponential increase in interventional procedures in our decade, electrophysiologists' need to cooperate with the anesthesiologists more frequently. The literature is still unclear about the effects of anesthetic agents on cardiac conduction pathways, but as we know with our previous data, the most agents we are using currently have more or less effect on the cardiac conduction systems. In this review, we aimed to describe the safe anesthesia methods in cardiac diagnostic procedures and have a closer look up the anesthetic outcomes of these procedures. This article comprehensively reviews the anesthesia practice encountered in electrophysiology laboratories.

Outcome of slow pathway modulation for atrioventricular nodal reentrant tachycardia with 50 versus 30 watts-more power, more effect?

PURPOSE

Slow pathway modulation is the treatment of choice in patients with atrioventricular nodal reentrant tachycardia (AVNRT). No comparative data on ablation strategies exist. Therefore, we sought to compare two common ablation approaches.

METHODS

We analyzed prospective ablation databases of two high-volume tertiary centers (> 1000 ablations/year) using either 30 or 50 W for slow pathway modulation from 2012 to 2013. We analyzed procedural characteristics as well as short- and long-term outcomes. Mean follow-up was 36 ± 9 months.

RESULTS

Six hundred thirty-four patients (50 W center: n = 342, 30 W center: n = 292) were ablated. Slow pathway modulation was successful in 99% in both groups (p = ns). Periprocedural AV block occurred in nine patients (2.6%) in the 50 W and five patients (1.7%) in the 30 W group (p = 0.59), respectively. We documented no permanent higher-degree AV block. The number of RF lesions and seconds of RF delivery was significantly less in the 50 W group (p = 0.04 for number of lesions; p < 0.001 for seconds). AVNRT recurrence was similar (p = 0.23). In males, significantly fewer recurrences accrued in the 50 W group (p = 0.04), while in females less transient AV blocks occurred during the procedure with 30 W (p = 0.07).

CONCLUSIONS

The 30 and 50 W target power approaches for slow pathway modulation are highly effective and safe. Significantly, fewer RF duration was necessary to modulate the slow pathway with higher power output (50 W). Our subgroup analysis suggests that males and females might benefit most from different modulation approaches.

Sedation in cardiac arrhythmias management

INTRODUCTION

Procedural sedation is of paramount importance for a plethora of electrophysiological procedures. From electrical cardioversion to electrophysiology studies, device implantations, and catheter ablations, intraprocedural sedation and anesthesia have a pivotal role in allowing procedural success while ensuring patient safety and avoiding discomfort. Areas covered: The present review will discuss the current state-of-the-art in sedation and anesthesia during electrical cardioversion, cardiac implantable electronic device implantation, catheter ablation and electrophysiology studies. Specific information will be provided for each procedure in order to reach the core of this important clinical issue, and specific protocols will be compared. The main pro-arrhythmic and anti-arrhythmic effects of the most commonly used sedatives will also be discussed. Expert commentary: According to much recent evidence, the cardiologist can be the only person responsible for sedation administration in many settings, highlighting few safety issues associated with the absence of a dedicated anesthesiologist thus a concomitant reduction in costs. However, many concerns have been raised in allowing non-anesthesiologists to manage sedatives, as adverse events, while rare, could have catastrophic consequences. The present paper will highlight when a cardiologist-directed sedation is considered safe, how it should be performed, and the pros and cons related to this strategy.

Anesthesia in the Electrophysiology Laboratory

The electrophysiology suite is a foreign location to many anesthesiologists. The initial experience was with shorter procedures under conscious sedation, and the value of greater tailoring of the sedation/anesthesia by anesthesiologists was not perceived until practice patterns had already been established. Although better control of ventilation with general anesthesia may be expected, suppression of arrhythmias, blunting of the hemodynamic adaptation to induced arrhythmias, and interference by muscle relaxants with identification of the phrenic nerve may be seen. We review a range of electrophysiology procedures and discuss anesthetic approaches that balance patient safety and favorable outcomes.

Effects of propofol sedation on pacing thresholds : Results from an observational cohort study

BACKGROUND

Propofol is one of the most commonly used intravenous anaesthetic drugs for surgical procedures. The use of propofol for sedation is also common practice during endoscopic procedures, electrophysiology studies, and ablation procedures, as well as pacemaker and defibrillator implantation. It was found that propofol alters the electrophysiologic properties of the heart and its conduction system. The effects of propofol on pacing thresholds are unknown and could have implications for pacemaker (PM) and defibrillator (ICD) implantation procedures, as well as sedation and anaesthesia in PM and ICD patients in general.

OBJECTIVES

We sought to investigate the effects of propofol sedation on atrial and right ventricular pacing thresholds in PM and ICD patients.

MATERIALS AND METHODS

A total of 50 patients with PM, ICD, or cardiac resynchronization therapy (CRT) undergoing propofol sedation for electrophysiology (EP) investigation, transesophageal echocardiography (TEE), electrocardioversion (ECV), or bronchoscopy were included prospectively. Pacing thresholds, impedance, and sensing were assessed by device interrogation immediately prior to sedation and after the desired sedation depth was achieved by the administration of propofol.

RESULTS

Mean atrial (0.68 V vs 0.77 V, p = 0.136) and mean right ventricular thresholds (0.90 V vs 0.93 V, p = 0.274) remained unchanged. Impedances and sensing remained unaffected in all patients.

CONCLUSIONS

Propofol sedation did not affect pacing thresholds of atrial and right ventricular leads in this cohort of PM and ICD patients.

Effects of propofol on ventricular repolarization and incidence of malignant arrhythmias in adults

BACKGROUND

Propofol is commonly used for procedural sedation in interventional electrophysiology. However, ventricular arrhythmias under Propofol have been reported. Our aim was to investigate ventricular repolarization and incidence of ventricular arrhythmias under Propofol infusion in adults with cardiac arrhythmias.

METHODS

QRS, QTcB (Bazett), QTcFri (Fridericia), JTc, measurement of T peak to Tend time (T_p-e) at baseline and under Propofol infusion was performed in 235 patients. Screening for unexpected ventricular arrhythmias was performed in 1165 patients undergoing EP procedures under Propofol.

RESULTS

A significant prolongation of T_p-e under Propofol infusion (79.7±17.3 vs. 86.4±22.5ms, p<0.001) and of QTcFri (429.3±35.8 vs. 435.5±36.5, p=0.033) was detected. No significant change of the QTcB interval, JTc interval or QRS duration was observed. One case (0.09%) of ventricular fibrillation during rapid ventricular pacing under Propofol occurred.

CONCLUSION

Although transmural dispersion of ventricular repolarisation is increased under Propofol, incidence of malignant ventricular arrhythmias is low. For evaluation of QT interval under Propofol, Fridericia's correction formula should be used rather than Bazett's formula.

Ketamine infusion for refractory status epilepticus: A case report of cardiac arrest

BACKGROUND

Refractory status epilepticus (RSE) has a high mortality rate and is often difficult to treat. When traditional therapies fail ketamine may be considered. There are limited reports of adverse cardiac events with the use of ketamine for RSE and no reports of cardiac arrest in this context.

OBJECTIVE

Evaluate the occurrence of cardiac arrhythmias associated with the use of ketamine for RSE.

METHODS

Retrospective chart review of nine patients who underwent ketamine infusion for RSE.

RESULTS

Etiology of refractory status epilepticus included autoimmune/infectious process (Zeiler et al., 2014), ischemic stroke (Bleck, 2005) and subarachnoid hemorrhage (Bleck, 2005). Of the nine patients who received ketamine, two had documented cardiac events; one remained clinically stable and the other developed multiple arrhythmias, including recurrent episodes of asystole. Once ketamine was discontinued the latter patient stabilized with the addition of anti arrhythmic therapy.

CONCLUSION

Ketamine is utilized to treat refractory status epilepticus, but should be used with caution in patients with subarachnoid hemorrhage, as there may be an increased risk of life threatening arrhythmias and cardiac arrest.

High Patient Satisfaction with Deep Sedation for Catheter Ablation of Cardiac Arrhythmia

BACKGROUND

Patients' satisfaction with invasive procedures largely relies on periprocedural perception of pain and discomfort. The necessity for intraprocedural sedation during catheter ablation of cardiac arrhythmias for technical reasons is widely accepted, but data on patients' experience of pain and satisfaction with the procedural sedation are scarce. We have assessed patients' pain and discomfort during and after the procedure using a standardized questionnaire.

METHODS

One hundred seventeen patients who underwent catheter ablation answered a standardized questionnaire on periprocedural perception of pain and discomfort after different anesthetic protocols with propofol/midazolam with and without additional piritramide and ketamine/midazolam.

RESULTS

Patients report a high level of satisfaction with periprocedural sedation with 83% judging sedation as good or very good. The majority of patients was unconscious of the whole procedure and did not recollect experiencing pain. Procedural pain was reported by 7.7% of the patients and 16% reported adverse effects, e.g., postprocedural nausea and episodes of headache.

CONCLUSION

The results of our study show that deep sedation during catheter ablation of cardiac arrhythmias is generally well tolerated and patients are satisfied with the procedure. Yet, a number of patients reports pain or adverse events. Therefore, studies comparing different sedation strategies should be conducted in order to optimize sedation and analgesia.

Moderate sedation in cardiac electrophysiology laboratory: a retrospective safety analysis

OBJECTIVE

Cardiac electrophysiology (EP) procedures can be performed under moderate sedation without the direct involvement of an anaesthetist. However, concerns have been raised over the safety of this approach. This study examines the use of a standardised nurse-led physician-directed sedation protocol for EP procedures to determine the safety of moderate sedation administered by non-anaesthesia personnel who have been trained in sedation techniques.

METHODS AND RESULTS

Consecutive EP procedures done under moderate sedation over 12 years at our institution were evaluated. Serious adverse events were defined as (i) procedural death related to sedation; (ii) intubation and ventilation; and (iii) hypotension requiring inotropic support. Reversal of sedation constituted a minor adverse event. Up to 7117 procedures were included. These comprised ablations (55%), devices (43%) and other procedures (2%). A majority of patients were men with a mean age of 61±10 years. 99.98% of procedures were completed successfully without sedation-related serious adverse events. Two patients (0.02%) required anaesthetic support for intubation. Sedation was reversed in 1.2% of procedures with less than 1% requiring reversal because of persistent drop in oxygen saturation, hypoventilation or markedly reduced level of consciousness. There was no significant difference in the patient characteristics, mean doses of sedative agents and procedure types in the group requiring reversal of sedation when compared with the whole cohort.

CONCLUSIONS

Our study demonstrates that nurse-led, physician-directed moderate sedation is safe. Anaesthesia services are not required routinely for invasive cardiac EP procedures and should be available on a need basis.

Ketamine-mediated afferent-specific presynaptic transmission blocks in low-threshold and sex-specific subpopulation of myelinated Ah-type baroreceptor neurons of rats

Background

Ketamine enhances autonomic activity, and unmyelinated C-type baroreceptor afferents are more susceptible to be blocked by ketamine than myelinated A-types. However, the presynaptic transmission block in low-threshold and sex-specific myelinated Ah-type baroreceptor neurons (BRNs) is not elucidated.

Methods

Action potentials (APs) and excitatory post-synaptic currents (EPSCs) were investigated in BRNs/barosensitive neurons identified by conduction velocity (CV), capsaicin-conjugated with Iberiotoxin-sensitivity and fluorescent dye using intact nodose slice and brainstem slice in adult female rats. The expression of mRNA and targeted protein for NMDAR1 was also evaluated.

Results

Ketamine time-dependently blocked afferent CV in Ah-types in nodose slice with significant changes in AP discharge. The concentration-dependent inhibition of ketamine on AP discharge profiles were also assessed and observed using isolated Ah-type BRNs with dramatic reduction in neuroexcitability. In brainstem slice, the 2^nd-order capsaicin-resistant EPSCs were identified and ∼50% of them were blocked by ketamine concentration-dependently with IC₅₀ estimated at 84.4 μM compared with the rest (708.2 μM). Interestingly, the peak, decay time constant, and area under curve of EPSCs were significantly enhanced by 100 nM iberiotoxin in ketamine-more sensitive myelinated NTS neurons (most likely Ah-types), rather than ketamine-less sensitive ones (A-types).

Conclusions

These data have demonstrated, for the first time, that low-threshold and sex-specific myelinated Ah-type BRNs in nodose and Ah-type barosensitive neurons in NTS are more susceptible to ketamine and may play crucial roles in not only mean blood pressure regulation but also buffering dynamic changes in pressure, as well as the ketamine-mediated cardiovascular dysfunction through sexual-dimorphic baroreflex afferent pathway.

Is There a Difference in Tachycardia Cycle Length during SVT in Children with AVRT and AVNRT?

BACKGROUND

There are limited adult data suggesting the tachycardia cycle length (TCL) of atrioventricular reentry tachycardia (AVRT) is shorter than atrioventricular nodal reentry tachycardia (AVNRT), though little data exist in children. We sought to determine if there is a difference in TCL between AVRT and AVNRT in children.

METHODS

A single-center retrospective review of children with supraventricular tachycardia (SVT) from 2000 to 2015 was performed.

INCLUSION CRITERIA

Age ≤ 18 years, invasive electrophysiology study (EPS) confirming AVRT or AVNRT.

EXCLUSION CRITERIA

Atypical AVNRT, congenital heart disease, antiarrhythmic medication use at time of EPS. Data were compared between patients with AVRT and AVNRT via t-test, χ² test, and linear regression.

RESULTS

A total of 835 patients were included (12 ± 4 years, 52 ± 31 kg, TCL 321 ± 55 ms), 539 (65%) with AVRT (270 Wolff-Parkinson-White, 269 concealed pathways) and 296 (35%) with AVNRT. Patients with AVRT were younger (11.7 ± 4.1 years vs 13.0 ± 3.6 years, P < 0.001) and smaller (49 ± 22 kg vs 57 ± 43 kg, P < 0.001). In the baseline state, the TCL was shorter in AVRT than AVRNT (329 ± 51 ms vs 340 ± 60 ms, P = 0.04). In patients requiring isoproterenol to induce SVT, there was no difference in TCL (290 ± 49 ms vs 297 ± 49 ms, P = 0.26). When controlling for age, there was no difference in TCL between AVRT and AVNRT at baseline or on isoproterenol. The regression equation for TCL in the baseline state was TCL = 290 + 4 (age), indicating the TCL will increase by 4 ms above a baseline of 290 ms for each year of life.

CONCLUSIONS

When controlling for age, there is no difference in the TCL between AVRT and AVNRT in children. Age, not tachycardia mechanism, is the most significant factor in predicting TCL.

Catheter ablation of premature ventricular contractions in elderly patients: feasibility and success

BACKGROUND

Catheter ablation has become a standard curative treatment for symptomatic, drug refractory premature ventricular contractions (PVC). The aim of this study was to investigate the efficacy and safety of this procedure in elderly patients.

METHODS AND RESULTS

A total of 101 consecutive patients (mean age 50.7 ± 16.9, 53 % women) presenting to our center for ablation of PVC were included and assigned to two age groups (<65 and ≥65 years). Clinical characteristics, procedural parameters, complications and success after 6-month follow up were compared between the two groups. Patients ≥65 years (n = 27) showed a higher rate of hypertension (78 vs. 27 %, p < 0.001), coronary artery disease (19 vs. 12 %, p = 0.01), renal insufficiency (22 vs. 1 %, p < 0.001) and diabetes (22 vs. 3 %, p = 0.001). Left ventricular ejection fraction did not differ between the two groups (56.6 vs. 57.4 %, p = 0.497). In patients <65 years the origin of the PVC was significantly more often in RVOT or LVOT (95 vs. 70 %, p = 0.001). Acute success rates (67 vs. 73 %, p = 0.545) and success rates after 6 months (81 vs. 86 %, p = 0.795) were not different between the two groups. Two complications were observed, both occurred in the <65 years group (1 pericardial effusion and 1 large groin hematoma).

CONCLUSION

Catheter ablation of PVC is feasible in elderly patients without overt heart disease. Success rates are not significantly different compared to patients <65 years. Procedural complications are rare in both the groups. Ablation of this arrhythmia can therefore be regarded as a promising curative treatment in advanced age.

Acute decrease of cerebral oxygen saturation during rapid ventricular and supraventricular rhythm: a pilot study

BACKGROUND

Monitoring of cerebral tissue oxygen saturation (SctO2 ) reflects cerebral microcirculation. We sought to characterize the decrease in SctO2 during supraventricular tachycardia (SVT) and ventricular tachycardia (VT) in adults.

METHODS

Twenty patients (mean age: 46.3 ± 18.1 years, 40% men) were included. Rapid atrial and ventricular pacing (200/min) was used as a model for VT and SVT. Near-infrared spectroscopy (NIRS) was used to measure SctO2 .

RESULTS

Atrial stimulation decreased right (P = 0.014) and left (P = 0.019) hemispheric SctO2 compared to baseline. Ventricular stimulation also decreased right (P < 0.001) and left (P < 0.001) hemispheric SctO2 . A negative correlation between age and minimal value under stimulation was found for atrial (right SctO2 r = -0.641, P = 0.034; left SctO2 r = -0.694, P = 0.018) and ventricular pacing (right SctO2 r = -0.564, P = 0.01; left SctO2 r = -0.604, P = 0.005). A positive correlation was found between left ventricular ejection fraction (LVEF) and minimal value under ventricular stimulation (right SctO2 r = 0.567, P = 0.009; left SctO2 r = 0.471, P = 0.036).

CONCLUSION

Cerebral perfusion decreased during simulated SVT and VT and is influenced by age and LVEF. Clinicians can consider NIRS monitoring in patients during ablation procedures and in critical care. NIRS may especially be appropriate for the elderly and for patients with impaired LVEF.

Improvement of cerebral oxygen saturation after successful electrical cardioversion of atrial fibrillation

AIMS

Cerebral and microvascular perfusion is reduced in atrial fibrillation (AF). Maintenance of brain perfusion is important in acute disease and long-term course. Assessment of brain perfusion and oxygenation is difficult in clinical practice. Our study aimed to determine changes in cerebral tissue oxygen saturation (SctO2) with bedside near-infrared spectroscopy (NIRS).

METHODS AND RESULTS

Twenty patients (mean age 67.7 ± 10.2 years, 50% men) in whom electrical cardioversion (CV) was successful were prospectively studied. Ten patients (mean age 64.2 ± 7.7 years, 80% men) in whom CV was not successful served as control group. Bilateral SctO2, mean arterial pressure (MAP), arterial oxygen saturation (SaO2), and heart rate were recorded and changes of all parameters before and after CV were compared between the groups. Our results show an increase in SctO2 after successful CV that was significantly higher compared with patients who remained in AF (right SctO2 3.25 ± 2.5 vs. -0.13 ± 0.52%, P = 0.001; left SctO2 4.27 ± 3.56 vs. -0.38 ± 2.4%, P < 0.001). Neither arterial blood pressure nor SaO2 changes differed significantly between the two groups. No correlation could be detected between the significant increase of SctO2 after successful CV and arterial blood pressure, SaO2, or heart rate.

CONCLUSION

Cerebral tissue oxygen saturation increases significantly after restoration of sinus rhythm. Near-infrared spectroscopy monitoring can identify changes of SctO2 after successful CV of AF independent from standard monitoring parameters (MAP, SaO2). Near-infrared spectroscopy can be used to detect cerebral oxygen saturation deficits in AF patients or patients at high risk for AF. Clinical applications may include monitoring during ablation procedures and in critical care.