Impact of anaesthetic drugs and adjuvants on ECG markers of torsadogenicity

Prediction of anesthetic torsadogenicity using a human ventricular cell model

This simulation study was designed to predict the torsadogenicity of sevoflurane and propofol in healthy control, as well as type 1 and type 2 long QT syndrome (LQT1 and LQT2, respectively), using the O'Hara-Rudy dynamic model. LQT1 and LQT2 models were simulated by decreasing the conductances of slowly and rapidly activating delayed rectifier K+ currents (IKs and IKr, respectively) by 50%, respectively. Action potential duration at 50% repolarization level (APD50) and diastolic intracellular Ca2+ concentration were measured in epicardial cell during administration of sevoflurane (1 ~ 5%) and propofol (1 ~ 10 μM). Torsadogenicity can be predicted from the relationship between APD50 and diastolic intracellular Ca2+ concentration, which is classified by the decision boundary. Whereas the relationships in control and LQT1 models were distributed on nontorsadogenic side in the presence of sevoflurane at all tested concentrations, those in LQT2 models were shifted to torsadogenic side by concentrations of ≥ 2%. In all three models, propofol shifted the relationships in a direction away from the decision boundary on nontorsadogenic side. Our findings suggest that sevoflurane, but not propofol, exerts torsadogenicity in patients with reduced IKr, such as LQT2 patients. Caution should be paid to the occurrence of arrhythmia during sevoflurane anesthesia in patients with reduced IKr.

Total Intravenous Anaesthesia for Laparoscopic Cholecystectomy in a Patient With Congenital Long QT Syndrome: A Case Report

Long QT syndrome (LQTS) is characterised by QT interval prolongation and ventricular arrhythmia, leading to sudden cardiac death. Patients with acquired or congenital LQTS pose special challenges to anaesthetists perioperatively due to the risk of developing life-threatening arrhythmia. A variety of medications, including commonly used volatile anaesthetic agents are known to prolong QT interval and there has been growing evidence of using total intravenous anaesthesia (TIVA) instead of volatile agents for such patients.  This is a case report of a 30-year-old patient with congenital LQTS and subcutaneous implantable cardioverter defibrillator (SICD) in situ who underwent laparoscopic cholecystectomy and endoscopic retrograde cholangiopancreatography (ERCP) under TIVA safely within two months. There were no arrhythmic events observed perioperatively.  This case highlights the importance of comprehensive planning and meticulous preparation to avoid all possible QT-prolonging conditions during the perioperative period, especially in patients with acquired or congenital LQTS.

Anesthetic management for inhibiting sympathetic activation in an adolescent patient diagnosed with catecholaminergic polymorphic ventricular tachycardia and undergoing left cardiac sympathetic denervation: A case report

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a genetic disorder in which catecholamine release during exercise or emotional stress cause fatal tachyarrhythmias. In this paper, we discuss methods to minimize the sympathetic stimulation that can occur during the perioperative period in patients undergoing left cardiac sympathetic denervation to surgically treat CPVT.

Thoracic epidural analgesia prolongs postoperative QT interval on electrocardiogram in major non-cardiac surgery: a randomized comparison and a prospective cohort analysis

Introduction: Prolongation of QT interval on electrocardiogram can be associated with perioperative lethal arrhythmia. Epidural analgesia is a commonly used modality to relieve surgical pain by blocking sensory nerves, which also blocks the autonomic nervous system and can affect QT interval. Since patient monitoring becomes much less frequent after surgery than intraoperative period, we investigated the effects of epidural analgesia on postoperative QT interval with a randomized clinical trial and a prospective cohort study. Methods: In a randomized study, we assigned 60 patients undergoing thoracic epidural analgesia to an epidural analgesia or no-epidural analgesia group, in which 3 ml/h of 0.25% epidural levobupivacaine (7.5 mg/h) was administered only in the epidural analgesia group during surgery. The primary outcome was the postoperative heart rate-corrected QT interval. In a prospective cohort study, patients were assigned to receive 5 ml/h epidural levobupivacaine (12.5 mg/h). The plasma concentration of levobupivacaine was measured using liquid chromatography-mass spectrometry. Results: The median postoperative corrected QT interval interval with 3 ml/h epidural levobupivacaine was significantly longer than that without epidural analgesia. Using multiple regression analysis for the factors known to affect postoperative corrected QT interval interval, epidural analgesia was found to be an independent variable for prolongation, and the mean difference of the corrected QT interval interval with or without epidural analgesia was 23 ms after adjustment. The median plasma concentration of levobupivacaine at the end of surgery was 164 ng/ml with 3 ml/h epidural levobupivacaine, and the correlation coefficient to the postoperative corrected QT interval interval was 0.14, showing a not significant correlation. A prospective cohort study showed that 5 ml/h epidural levobupivacaine significantly prolonged postoperative corrected QT interval interval compared to preoperative baseline. The median plasma concentration of levobupivacaine was 166 ng/ml with 5 ml/h, the correlation coefficient of which showed no significant correlation. Conclusion: Thoracic epidural analgesia could enhance postoperative corrected QT interval prolongation after general anesthesia. The mechanism is possibly caused by blocking neighboring or part of the cardiac sympathetic nerves, rather than by systemic effects of epidurally administered levobupivacaine. Clinical trial number: UMIN000013347 for the randomized study and UMIN000041518 for the prospective cohort study, which were registered at University hospital Medical Information Network Center.

Assessment of cardiotoxicity and plasma ropivacaine concentrations after serratus intercostal fascial plane block in an experimental model

Serratus intercostal fascial plane block (SIFPB) has emerged as an alternative to paravertebral block in breast surgery. It involves the administration of high volumes and doses of local anesthetics (LA) that can potentially reach toxic levels. Ropivacaine is widely used in thoraco-fascial blocks; however, there is no information on the plasma concentrations attained after SIPFB and whether they are associated with cardiotoxicity. Plasma concentrations of ropivacaine and its electrophysiological effects were evaluated in eight pigs after bilateral SIFPB with ropivacaine in doses of 3 mg/kg. Plasma concentrations, electrophysiological and hemodynamic parameters were measured sequentially for the following 180 min until the end of the study. The area under the curve, the maximum plasma concentration (C_max) and the time to reach C_max (t_max) were calculated. The median arterial ropivacaine concentration C_max was, 2.34 [1.40 to 3.74] µg/ml. The time to reach the highest concentration was 15 [10 to 20] min. Twenty-five percent of the animals had arterial concentrations above the lower limit concentration of ropivacaine for LA systemic toxicity (3.4 µg/ml). No alterations were observed in the electrophysiological or electrocardiographic parameters except for a prolongation of the QTc interval, from 489 ± 30 to 544 ± 44 ms (Δ11.38 ± 6%), P = 0.01. Hemodynamic parameters remained in the physiological range throughout the study. SIFPB with ropivacaine in doses of 3 mg/kg has reached potentially toxic levels, however, it has not been associated with adverse electrophysiological or hemodynamic effects.

Anaesthesia for elite athletes

BACKGROUND

Sports participation has been growing rapidly since the 1960s. Anaesthesiologists are increasingly confronted with athletes in a peri-operative setting. The right choice of type of anaesthesia technique, pain management of injuries, specific physiologic adaptations of the athlete and knowledge of prohibited substances are eminent for a correct approach of this subpopulation.

PURPOSE

This review aims to give an overview of athletes' specific anaesthetic management in peri-operative and postoperative settings and to guide the nonspecialised anaesthetist.

METHODS

We comprehensively reviewed the literature, gathered all the information available on, and synthesised it in a narrative way, regarding preoperative evaluation, intraoperative implications and postoperative pain management of the elite athlete undergoing a surgical procedure.

RESULTS

An anaesthesiologist should recognise the most common benign ECG findings in athletes like bradycardia, isolated left ventricle hypertrophy on voltage criteria and early repolarisation as normal features in the athlete's heart. Isotonic physiology typically produces four-chamber dilation. In contrast, isometric stress creates high intravascular pressure leading to left ventricular hypertrophy. Pre-operative evaluation should also identify possible consumers of performance-enhancing drugs. Intraoperative points of interest for the anaesthesiologist is mainly avoiding drugs on the prohibited list of the World Anti-Doping Agency (WADA). Postoperative and chronic pain management are still developing fields in this population. The International Olympic Committee (IOC) proposed treating acute pain with a combination of paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), topical analgesics, injectable NSAIDs and local anaesthetics. It may be suggested that chronic pain management in elite athletes could benefit from treatment in specialised multidisciplinary pain clinics.

CONCLUSION

This literature review aims to serve as a guide for the anaesthesiologist taking care of the elite athlete.

Effects of Fentanyl Versus Remifentanil Pretreatment on the QTc Interval in Patients Undergoing Rapid Sequence Intubation: A Randomized Clinical Trial

Background

One of the complications of laryngoscopy is cardiac dysrhythmia due to an increased QT interval.

Objectives

This study aimed to compare the effect of fentanyl and remifentanil on QTc interval in patients undergoing intubation by the rapid method in 2020.

Methods

In this study, 50 patients without a history of heart disease and without a history of drug use who were candidates for rapid intubation in the emergency department were selected and divided into two groups. Before the injection of intubation drugs, a baseline ECG was obtained from the patient and then randomly assigned to one group of patients with 2 μg/kg fentanyl and the other group with 1 μg/kg remifentanil. Other intubation drugs, including lidocaine, etomidate, and succinylcholine, were fixed in both groups. Immediately after drug injection and immediately after laryngoscopy, ECG was prepared from patients, and the QT interval was calculated.

Results

In group comparison, changes in QT values during the studied time were statistically significant (P = 0.004). However, in the comparison between groups, there was no statistically significant difference between the two groups receiving fentanyl and remifentanil (P = 0.235). The results showed that the rate of QT interval changes during three different measurements increased in both groups of patients receiving fentanyl and remifentanil.

Conclusions

In the present study, in comparing the QT interval, there was a statistically significant difference between the two groups receiving fentanyl and remifentanil at any of the studied times. Therefore, fentanyl and remifentanil during endotracheal intubation did not have a statistically and clinically significant effect on the QT distance of patients' ECG, and the administration of the above two drugs during intubation was safe.

The Effect of Low-Flow and Normal-Flow Desflurane Anesthesia on the Frontal QRS-T Angle in Patients Undergoing Rhinoplasty Operation: A Randomized Prospective Study

Introduction: Low-flow anesthesia (LFA) has gained more interest worldwide owing to its economic and ecological advantages compared to normal-flow anesthesia (NFA). Desflurane is one of the commonly used anesthetic agents for LFA, but it may prolong myocardial repolarization. Frontal QRS-T angle (f[QRS-T]a) is a novel marker of myocardial repolarization. To our knowledge, no study has compared the effect of LFA and NFA on f(QRS-T)a. In this study, we aimed to compare the effect of the LFA and NFA with desflurane on f(QRS-T)a in patients undergoing rhinoplasty operation.

Methods: A total of 80 patients undergoing rhinoplasty operations were included in this prospective study. The patients were randomized into two groups as follows: LFA (n = 40) and NFA (n = 40). The frontal QRS-T angle was calculated from the automatic report of the electrocardiography device (Nihon Kohden, Tokyo, Japan). It was recorded at the following time points: T1: preoperative (basal), T2: immediately after anesthesia induction, T3: immediately after endotracheal intubation, T4: 5 min after endotracheal intubation, T5: 15 min after endotracheal intubation, T6: 30 min after endotracheal intubation, T7: 60 min after endotracheal intubation, T8: end of the operation, T9: 15 min after the end of the operation.

Results: Baseline clinical characteristics and laboratory parameters were similar between the two groups. In the LFA group, f(QRS-T)a was significantly increased at only the T3 time point when compared to T1 (P = 0.003). However, in the NFA group, f(QRS-T)a was significantly increased at T3, T4, T5, T6, T7, T8, and T9 time points when compared to the T1 value (P < 0.05, for all). On the other hand, fQRS-Ta was significantly higher in the NFA group than in the LFA group at T4, T5, and T6 time points. 

Conclusion: In our study, we have shown for the first time that NFA significantly increased the f(QRS-T)a, whereas LFA did not significantly increase the f(QRS-T)a except for immediately after the endotracheal intubation. It was also detected that f(QRS-T)a was significantly higher in the NFA group compared to that in the LFA group. Therefore, it can be concluded that LFA has more protective effects on myocardial repolarization than NFA.

Effects of dexmedetomidine on cardiac electrophysiology in patients undergoing general anesthesia during perioperative period: a randomized controlled trial

Background

Dexmedetomidine has controversial influence on cardiac electrophysiology. The aim of this study was to explore the effects of dexmedetomidine on perioperative cardiac electrophysiology in patients undergoing general anesthesia.

Methods

Eighty-one patients were randomly divided into four groups: groups D₁, D₂, D₃ receiving dexmedetomidine 1, 1, 0.5 μg/kg over 10 min and 1, 0.5, 0.5 μg/kg/h continuous infusion respectively, and control group (group C) receiving normal saline. Twelve-lead electrocardiograms were recorded at the time before dexmedetomidine/normal saline infusion (T₁), loading dose finish (T₂), surgery ending (T₆), 1 h (T₇) after entering PACU, 24 h (T₈), 48 h (T₉), 72 h (T₁₀) and 1 month (T₁₁) postoperatively. Cardiac circulation efficiency (CCE) were also recorded.

Results

Compared with group C, QTc were significantly increased at T₂ in groups D₁ and D₂ while decreased at T₇ and T₈ in group D₃ (P < 0.05), iCEB were decreased at T₈ (P < 0.05). Compared with group D₁, QTc at T₂, T₆, T₇, T₉ and T₁₀ and iCEB at T₈ were decreased, and CCE at T₂-T₄ were increased in group D₃ significantly (P < 0.05). Compared with group D₂, QTc at T₂ and iCEB at T₈ were decreased and CCE at T₂ and T₃ were increased in group D₃ significantly (P < 0.05).

Conclusions

Dexmedetomidine at a loading dose of 0.5 μg/kg and a maintenance dose of 0.5 μg/kg/h can maintain stability of cardiac electrophysiology during perioperative period and has no significant adverse effects on CCE.

Trial registration

ClinicalTrials.gov NCT04577430 (Date of registration: 06/10/2020).

Anesthesia induction regimens may affect QT interval in cardiac surgery patients: A randomized-controlled trial

Background: The aim of this study was to investigate the effects on QT interval of the propofol-ketamine combination and the midazolam-fentanyl combination in anesthesia induction for cardiac surgery.

Methods: Between September 2020 and June 2021, a total of 9 5 c ardiac s urgery p atients ( 80 m ales, 1 5 f emales; mean age: 57±9.1 years; range, 26 to 76 years) were included. The patients were divided into two groups as Group PK (propofol-ketamine, n=50) and Group MF (midazolam-fentanyl, n=45). The 12-lead electrocardiographic and hemodynamic measurements were performed at three time points: before anesthesia induction, after anesthesia induction, and after endotracheal intubation. The measurements were evaluated with conventional Bazett's formula and a new model called index of cardio-electrophysiological balance.

Results: The evaluated QTc values of 95 patients after anesthesia induction were significantly prolonged with the Bazett's formula and the index of cardio-electrophysiological balance in Group PK (p=0.034 and p=0.003, respectively). A statistically significant QTc prolongation was observed with the index of cardio-electrophysiological balance after laryngoscopy and endotracheal intubation in Group PK (p=0.042). Hemodynamic parameters were also higher in Group PK.

Conclusion: Our study shows that the propofol-ketamine combination prolongs the QTc value determined by the Bazett's formula and the index of cardio-electrophysiological balance model. Using both QTc measurement models, the midazolam-fentanyl combination has no prolongation effect on QTc interval in coronary surgery patients.

The impact of midazolam used in cataract surgery sedation on frontal QRS-T angle

WHAT IS KNOWN AND OBJECTIVE

Midazolam is one of the most commonly used drugs in procedures requiring sedoanalgesia. It affects the myocardium's ventricular depolarization and repolarization. Previous studies examining the arrhythmogenic effects of midazolam yielded conclusive results. These studies are based on QT and Tp -e distances. The frontal QRS-T angle (f-[QRS-T]a) is a new electro cardiac parameter that shows the heterogeneity of ventricular electrical activity. This study aims to examine the effect of midazolam on f-(QRS- T)a and other depolarization-repolarization parameters in patients who have had cataract surgery.

METHODS

The study included 177 patients administered midazolam as a sedoanalgesia during cataract surgery. The sedative effect was evaluated 2-3 minutes after a 0.05 mg/kg dose of midazolam was given. Sedation was assessed again by giving 0.5 mg every 2-3 minutes until the desired level of sedation was achieved. 12-lead electrocardiogram (ECG) recordings of all patients were taken just before and immediately after surgery. ECGs were used to calculate the QT interval, QTc interval, Tp -e interval, Tp -e/QT, Tp -e/ QTc ratios and f-(QRS-T)a.

RESULTS AND DISCUSSION

After cataract surgery, f-(QRS-T)a was unchanged compared to presurgery (29.14 ± 4.52 vs. 29.18 ± 5.39, p = 0.852). In addition, no significant change in QT(351.32 ± 21.98 vs. 351.94 ± 22.44, p = 0.091), QTc (384.05 ± 24.52 vs. 385.19 ± 26.12, p = 0.819), Tp -e interval (93.12 ± 9.60 vs. 94.44 ± 8.82, p = 0.179) and Tp -e/QT (0.27 ± 0.02 vs. 0.28 ± 0.03, p = 0.664), Tp -e/ QTc ratios (0.28 ± 0.02 vs. 0.29 ± 0.03, p = 0.655) was observed after surgery when compared to presurgery values. Significant ventricular and supraventricular arrhythmias were not observed in any patient during the operation.

WHAT IS NEW AND CONCLUSION

Midazolam did not affect f -(QRS-T) with classical repolarization parameters in patients who underwent cataract surgery, according to this study. Midazolam has been found to be safe for the heart in sedoanalgesia. These results show that sedation with midazolam can be performed without electrocardiogram monitoring.

Heart-Rate-Corrected QT Interval Response to Ramosetron during Robot-Assisted Laparoscopic Prostatectomy: A Randomized Trial

Ramosetron, often used to prevent postoperative nausea and vomiting, might cause heart-rate-corrected (QTc) interval prolongation, as might robot-assisted laparoscopic prostatectomy (RALP), which requires a steep Trendelenburg position and CO2 pneumoperitoneum. This study aimed to determine how ramosetron administration affects the QTc interval in patients treated with RALP. Fifty-six subjects were randomly assigned to ramosetron (n = 28) or control (n = 28) groups. The ramosetron group received 0.3 mg of ramosetron after anesthetic induction, whereas the control group received normal saline. The QTc interval was measured before and after induction; after 5, 30, and 60 min of being placed in the Trendelenburg position; immediately after being returned to a supine position; and at the end of surgery. Linear mixed models were used to compare QT intervals between groups. QTc intervals did not differ significantly between groups over time (Pgroup×time = 0.111). However, they increased significantly in both groups after placement in the Trendelenburg position compared with before induction (Ptime < 0.001). This increase in QTc continued until the end of surgery in both groups. Based on these findings, ramosetron can be safely administered for the prevention of postoperative nausea and vomiting among patients undergoing RALP.

Propofol prevents further prolongation of QT interval during liver transplantation

Here, we aimed to compare the effects of two anesthetic methods (desflurane inhalation anesthesia vs. propofol-based total intravenous anesthesia (TIVA)] on corrected QT interval (QTc) values during living donor liver transplantation. Altogether, 120 patients who underwent living donor liver transplantation were randomized to either the desflurane or TIVA group. The primary outcome was intraoperative QTc change. Other electrocardiogram, hemodynamic findings and postoperative outcomes were examined as secondary outcomes. QTc values were prolonged intraoperatively in both groups; however, the change was smaller in the TIVA group than in the desflurane group (P_{Group × Time} < 0.001). More patients had QTc values of > 500 ms in the desflurane group than in the TIVA group (63.3% vs. 28.3%, P < 0.001). In patients with preoperative QTc prolongation, QTc was further prolonged in the desflurane group, but not in the TIVA group (P_{Group × Time} < 0.001). Intraoperative norepinephrine and vasopressin use were higher in the desflurane group than in the TIVA group. Propofol-based TIVA may reduce QTc prolongation during living donor liver transplantation compared to that observed with desflurane inhalational anesthesia, particularly in patients with preoperative QTc prolongation. Additionally, patients managed with propofol-based TIVA required less vasopressor during the procedure as compared with those managed with desflurane inhalational anesthesia.

Left Frontal Lobe Tumor-Induced Intraoperative Premature Ventricular Beats

In the absence of cardiac pathology, premature ventricular contractions (PVCs) in neurosurgical patients frequently accompany subarachnoid hemorrhage, intracerebral hemorrhage, traumatic brain injury, or raised intracranial pressure. PVCs detected during preanesthesia assessment prompts detailed cardiac evaluation. Our 57-year-old patient, a case of left frontal meningioma, with controlled hypertension, diabetes and hypothyroidism, had normal preoperative ECG and potassium. However, immediately on anesthesia induction, she developed multiple refractory to treatment PVCs but with normal blood pressure. Anesthesia, which was maintained with sevoflurane and fentanyl, was deepened to exclude light anesthesia as the cause, without useful outcome. Two lignocaine boluses (100 mg each), followed by its infusion, also proved ineffective. Her blood gases and potassium, checked twice, were normal. Throughout, her hemodynamics remained stable. As soon as tumor was removed, the PVCs disappeared not to return. Her postoperative recovery was uneventful with normal ECG.

Delayed Ventricular Tachycardia After Prophylactic Doses of Droperidol in Patients With Mild QT Interval Prolongation Due to Preoperative Medication

Prophylactic doses of droperidol are effective in preventing postoperative nausea and vomiting (PONV). However, due to concerns of QT interval prolongation and ventricular arrhythmias, the safety of droperidol for PONV prophylaxis has been debated.

A 70-year-old woman was scheduled for total knee arthroplasty. She had a history of aortic valve replacement. Oral aprindine (40 mg/day) was prescribed. Preoperative electrocardiogram showed mild QT interval prolongation (QTc = 475 ms). Anesthesia was induced using propofol, remifentanil, and rocuronium, and maintained using desflurane, remifentanil, and a bolus dose of rocuronium.

The surgery was uneventful. At the time of skin closure, droperidol (1.25 mg) was administered intravenously for PONV prophylaxis. Twenty-three minutes after administration of droperidol, a sudden onset of premature cardiac contraction was observed, which progressed directly to ventricular tachycardia and atrioventricular block. Arrhythmia due to droperidol-induced QT interval prolongation was strongly suspected. Intravenous magnesium sulfate (2 g) and atropine (0.5 mg) were administered immediately. The ventricular tachycardia resolved quickly after the magnesium injection. Following the resolution of the arrhythmia, the patient was extubated.

The patient experienced ventricular tachycardia after a prophylactic dose of droperidol that resulted from QT interval prolongation due to the preoperative medication. It may be prudent to avoid even low-dose droperidol in the background of already present QT prolongation, especially when multiple putative QT-prolonging drugs are used.

In vivo analysis of concentration-dependent effects of halothane or isoflurane inhalation on the electrocardiographic and hemodynamic variables in dogs

We assessed concentration-dependent effects of halothane or isoflurane inhalation on the electrocardiographic and hemodynamic variables using a cross-over design in intact beagle dogs (n = 4). Elevation of inhaled halothane from 1.0% to 2.0% or isoflurane from 1.5% to 2.5% decreased the mean blood pressure and prolonged the QRS width without significantly altering the heart rate, PR interval or QT interval. However, the observed changes disappeared after regressions of both anesthetic conditions to their initial settings. These results indicate that hypotension-induced, reflex-mediated increase of sympathetic tone may have counterbalanced the direct negative chronotropic, dromotropic and repolarization slowing effects of the anesthetics.

Perioperative pain management in COVID-19 patients: Considerations and recommendations by the Saudi Anesthesia Society (SAS) and Saudi Society of Pain Medicine (SSPM)

The COVID-19 pandemic has swept across the world over the past few months. Many articles have been published on the safety of anesthetic medications and procedures used in COVID-19 positive patients presenting for surgery. Several other articles covered the chronic pain management aspect during the pandemic. Our review aimed to focus on perioperative pain management for COVID-19 patients. We conducted a literature search for pertinent recent articles that cover considerations and recommendations concerning perioperative pain management in COVID-19 patients. We also searched the literature for the relevant adverse effects of the commonly used medications in the treatment of COVID-19, and their potential drug-drug interactions with the common medications used in perioperative pain management. Professional societies recommend prioritizing regional anesthesia techniques, which have many benefits over other perioperative pain management options. When neuraxial and continuous peripheral nerve block catheters are not an option, patient-controlled analgesia (PCA) should be considered if applicable. Many of the medications used for the treatment of COVID-19 and its symptoms can interfere with the metabolism of medications used in perioperative pain management. We formulated an up-to-date guide for anesthesia providers to help them manage perioperative pain in COVID-19 patients presenting for surgery.

Effect of different general anaesthetics on ventricular repolarisation in robot-assisted laparoscopic prostatectomy

BACKGROUND

Ventricular repolarisation is affected differently by the types of anaesthetics used. This study aimed to compare the effect of different types of anaesthetics on ventricular repolarisation during robot-assisted laparoscopic radical prostatectomy (RALP).

METHODS

Sixty-nine patients were randomly assigned in a 1:1:1 ratio to the Sevoflurane (sevoflurane/remifentanil), Desflurane (desflurane/remifentanil) or total intravenous anaesthesia (TIVA [propofol/remifentanil]) groups; however, only 67 patients completed the study. The primary outcome was heart rate-corrected QT (QTc) interval collected at nine time points during RALP. Bazett's (QTcB) and Fridericia's (QTcF) formulae were used for QT interval correction. The secondary outcomes were Tpeak-Tend (Tp-e) interval and Tp-e/QT ratio that were collected at the same time points.

RESULTS

The QTcB and QTcF intervals were significantly prolonged during surgery in all groups; however, these values showed significant intergroup differences with time. After assuming the Trendelenburg position, the QTcB and QTcF intervals were significantly longer in the Desflurane group than in the other two groups, and this prolongation continued until the end of surgery. Intra-operatively, the QTcB and QTcF intervals exceeded 450 ms in six and five patients, respectively, in the Desflurane group, but in none in the TIVA group. Moreover, the incidence of intra-operative QTc interval prolongation >20 ms and >60 ms was significantly higher in the Desflurane group than in the TIVA group. There were no significant differences in Tp-e intervals and Tp-e/QT ratio among the three groups during surgery.

CONCLUSIONS

To minimise QTc interval prolongation during RALP, TIVA with propofol/remifentanil is recommended for general anaesthesia.

Propofol abolishes torsade de pointes in different models of acquired long QT syndrome

There is conflicting evidence regarding the impact of propofol on cardiac repolarization and the risk of torsade de pointes (TdP). The purpose of this study was to elucidate the risk of propofol-induced TdP and to investigate the impact of propofol in drug-induced long QT syndrome. 35 rabbit hearts were perfused employing a Langendorff-setup. 10 hearts were perfused with increasing concentrations of propofol (50, 75, 100 µM). Propofol abbreviated action potential duration (APD₉₀) in a concentration-dependent manner without altering spatial dispersion of repolarization (SDR). Consequently, no proarrhythmic effects of propofol were observed. In 12 further hearts, erythromycin was employed to induce prolongation of cardiac repolarization. Erythromycin led to an amplification of SDR and triggered 36 episodes of TdP. Additional infusion of propofol abbreviated repolarization and reduced SDR. No episodes of TdP were observed with propofol. Similarly, ondansetron prolonged cardiac repolarization in another 13 hearts. SDR was increased and 36 episodes of TdP occurred. With additional propofol infusion, repolarization was abbreviated, SDR reduced and triggered activity abolished. In this experimental whole-heart study, propofol abbreviated repolarization without triggering TdP. On the contrary, propofol reversed prolongation of repolarization caused by erythromycin or ondansetron, reduced SDR and thereby eliminated drug-induced TdP.

Comparison of General Anesthesia (Sevoflurane) and Spinal Anesthesia (Levobupivacaine) Methods on QT Dispersion in Inguinal Hernia Operations

Introduction Arrhythmias are one of the most frequently seen issues during surgical operations. In this study, we investigated and compared the effects on the QT dispersion of patients when using a method of volatile inhalation mask anesthesia with sevoflurane (VIMA: Group I) and when spinal anesthesia was performed with levobupivacaine (Group II). Methods The study included 40 patients who had American Society of Anesthesiology scores of I-II (ASA I-II), were aged from 18 to 65 years, and were scheduled for inguinal hernia operations. Approval of the university ethics committee was obtained before the study began. All patients had measurements taken for non-invasive blood pressure, including systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP), heart rate (HR), and oxygen saturation (SO2) values. The QT intervals were measured using the 12-derivation electrocardiogram (ECG) device (Cardiofax V). Our study was performed with randomization using the closed envelope method. Results When the percentage differences of the HR values from the initial period in both groups were compared, we observed significant differences between the groups, with increases in the VIMA group at the second period as well as increases in the VIMA group at the fourth, fifth, sixth, seventh, and ninth periods but decreases in the spinal anesthesia group for these periods. There were statistically significant differences between the two groups at the third and fifth periods when the percentage differences of the QTc values from the initial period were compared. We observed increases in the spinal anesthesia group. Conclusion In our study, we suggest that the tendency toward arrhythmia may be reduced by choosing general anesthesia with sevoflurane rather than levobupivacaine in patients with cardiac complaints who are undergoing regional anesthesia and/or taking medication that affects QT intervals.

Evaluation of relationships between results of electrocardiography and echocardiography in 341 chimpanzees (Pan troglodytes)

OBJECTIVE

To examine potential relationships between ECG characteristics and echocardiographic measures of cardiac structure in chimpanzees (Pan troglodytes).

ANIMALS

341 chimpanzees (175 males and 166 females) from 5 sanctuaries and 2 zoological collections.

PROCEDURES

Chimpanzees were anesthetized for routine health examinations between May 2011 and July 2017 as part of the International Primate Heart Project and, during the same anesthetic events, underwent 12-lead ECG and transthoracic echocardiographic assessments. Relationships between results for ECG and those for echocardiographic measures of atrial areas, left ventricular internal diameter in diastole (LVIDd), and mean left ventricular wall thicknesses (MLVWT) were assessed with correlational analysis, then multiple linear regression analyses were used to create hierarchical models to predict cardiac structure from ECG findings.

RESULTS

Findings indicated correlations (r = -0.231 to 0.310) between results for ECG variables and echocardiographic measures. The duration and amplitude of P waves in lead II had the strongest correlations with atrial areas. The Sokolow-Lyon criteria, QRS-complex duration, and R-wave amplitude in leads V₆ and II had the strongest correlations with MLVWT, whereas the Sokolow-Lyon criteria, QRS-complex duration, and S-wave amplitude in leads V₂ and V₁ had the strongest correlations with LVIDd. However, the ECG predictive models that were generated only accounted for 17%, 7%, 11%, and 8% of the variance in the right atrial end-systolic area, left atrial end-systolic area, MLVWT, and LVIDd, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that relationships existed between ECG findings and cardiac morphology in the chimpanzees of the present study; however, further research is required to examine whether the predictive models generated can be modified to improve their clinical utility.

Plasma Hyperosmolality Prolongs QTc Interval and Increases Risk for Atrial Fibrillation in Traumatic Brain Injury Patients

Introduction: Hyperosmotic therapy with mannitol is frequently used for treatment cerebral edema, and 320 mOsm/kg H₂O has been recommended as a high limit for therapeutic plasma osmolality. However, plasma hyperosmolality may impair cardiac function, increasing the risk of cardiac events. The aim of this study was to analyze the relation between changes in plasma osmolality and electrocardiographic variables and cardiac arrhythmia in patients treated for isolated traumatic brain injury (iTBI). Methods: Adult iTBI patients requiring mannitol infusion following cerebral edema, and with a Glasgow Coma Score below 8, were included. Plasma osmolality was measured with Osmometr 800 CLG. Spatial QRS-T angle (spQRS-T), corrected QT interval (QTc) and STJ segment were calculated from digital resting 12-lead ECGs and analyzed in relation to four levels of plasma osmolality: (A) <280 mOsm/kg H₂O; (B) 280–295 mOsm/kg H₂O; (C) 295–310 mOsm/kg H₂O; and (D) >310 mOsm/kg H₂O. All parameters were measured during five consecutive days of treatment. Results: 94 patients aged 18-64 were studied. Increased plasma osmolality correlated with prolonged QTc (p < 0.001), intensified disorders in STJ and increased the risk for cardiac arrhythmia. Moreover, plasma osmolality >313 mOms/kg H₂O significantly increased the risk of QTc prolongation >500 ms. Conclusion: In patients treated for iTBI, excessively increased plasma osmolality contributes to electrocardiographic disorders including prolonged QTc, while also correlating with increased risk for cardiac arrhythmias.

Measurement and Management of QT Interval Prolongation for General Physicians

One of the more challenging aspects of ECG interpretation is measurement and interpretation of the QT interval. This interval represents the time taken for the ventricles to completely repolarise after activation. Abnormal prolongation of the QT interval can lead to torsades de pointes, a form of potentially life-threatening polymorphic ventricular tachycardia (VT). Detection of a prolonged QT interval is essential as this can be a reversible problem, particularly in the context of the use of a variety of commonly prescribed medications in the hospital setting. Automated ECG printouts cannot be relied upon to diagnose QT interval prolongation; thus, the onus is on the clinician to identify it. This is a difficult task, as the normal QT interval is typically measured relative to the heart rate. Therefore, the QT interval often requires "correction" for the current heart rate, in order to correctly stratify the risk of torsades de pointes. A wealth of correctional formulae have been derived, but none has proven superior. We present an approach to the ECG in this context, and a step-by-step guide to manually measuring and correcting the QT interval, and an approach to management in common hospital-based clinical scenarios.

Perianesthesia Implications and Considerations for Drug-Induced QT Interval Prolongation

Prolongation of the QT interval can predispose patients to fatal arrhythmias such as torsade de pointes. While arrhythmias can occur spontaneously in patients with a genetic predisposition, drugs such as ondansetron and droperidol, which are frequently used in the perioperative period, have been implicated in the prolongation of the QT interval. As the list of medications that cause QT prolongation grows, anesthesia providers and perioperative nurses must be informed regarding the importance of the QT interval. This article reviews the physiology and measurement of the QT interval, the risk factors of QT prolongation, the mechanism of drug-induced QT prolongation, and perioperative considerations for patient care.

Effects of different concentrations of desflurane on the index of cardiac electrophysiological balance in gynecologic surgery patients

The objectives were to observe the effects of different concentrations of desflurane on QT, QTc, Tp-e, Tp-e/QT, and the index of cardiac electrophysiological balance (iCEB). Sixty patients were randomly divided into group D₁, group D₂, and group D₃ by using a random number table, 20 in each group. After entering the operating room, patients received 10 mL/kg hydroxyethyl starch, 0.1 mg/kg midazolam, 0.1 mg/kg vecuronium, 3 μg/kg fentanyl, and 0.3 mg/kg etomidate intravenously and then accepted intubation and mechanical ventilation. The desflurane evaporator was opened. The concentrations of desflurane in the D₁, D₂, and D₃ groups were maintained at 0.6, 1.3, and 2.0 minimum alveolar concentration (MAC), respectively. Twelve-lead ECGs were recorded at time before induction (T₁) and at 20 min after desflurane reached the required concentration (T₂). HR and MAP were recorded measure and the QT interval, QTc interval, Tp-e interval, Tp-e/QT ratio, and iCEB were calculated. Compared with before inhalation (T₁), the QTc interval was prolonged in the D₁, D₂, and D₃ groups after inhalation of different concentrations of desflurane for 20 min (T₂) (P < 0.05) and the Tp-e/QT ratio decreased in the D₁ and D₂ groups at T₂ (P < 0.05). Compared with the D₁ and D₂ groups, the Tp-e/QT ratio of the D₃ group increased at T₂ (P < 0.05). There was no significant difference in Tp-e interval and iCEB at any time (P > 0.05). The study suggested that inhalation of desflurane at a normal concentration cannot cause arrhythmogenic characteristics and affect the cardiac electrophysiological stability.

Dopamine D2-receptor Antagonist Droperidol Deepens Sevoflurane Anesthesia

BACKGROUND

Although midbrain dopaminergic pathways are known to contribute to arousal and emergence from anesthesia, few reports exist regarding the anesthetic effects of dopamine D2 receptor antagonism in humans. This study examined the effect of the D2 receptor antagonist droperidol on sevoflurane anesthesia by examining α and slow wave electroencephalogram oscillations.

METHODS

Forty-five patients, age 20 to 60 yr, were enrolled. Frontal electroencephalograms were continuously collected for offline analysis via Bispectral Index monitoring. After induction of anesthesia, end-tidal sevoflurane concentration was deliberately maintained at 1%, and intravenous droperidol (0.05 mg/kg bolus) was administered. Electroencephalogram changes were examined in power spectrum and bicoherence, before and 10 min after droperidol injection, then compared using the Wilcoxon signed-ranks test and/or paired t test.

RESULTS

Droperidol significantly augmented the α-bicoherence peak induced by sevoflurane from 30.3% (24.2%, 42.4%) to 50.8% (41.7%, 55.2%) (median [25th, 75th percentiles]; P < 0.0001), Hodges-Lehman median difference, 15.8% (11.3 to 21.4%) (95% CI). The frequency of the α-bicoherence peak was simultaneously shifted to the lower frequency; from 11.5 (11.0, 13.0) to 10.5 (10.0, 11.0) Hz (median [25th, 75th percentiles], P < 0.0001). Averaged bicoherence in the δ-θ area increased conspicuously from 17.2% (15.6 to 18.7%) to 25.1% (23.0 to 27.3%) (mean [95% CI]; P < 0.0001), difference, 8.0% (6.0 to 9.9%).

CONCLUSIONS

Droperidol augments both α and δ-θ bicoherences while shifting the α-bicoherence peaks to lower frequencies, and enhances the effect of sevoflurane anesthesia on the electroencephalogram via γ-aminobutyric acid-mediated oscillatory network regulation.

Comparison of the Effects of Propofol and Sevoflurane on QT Interval in Pediatrics Undergoing Cochlear Implantation: A Randomized Clinical Trial Study

Background

Children with sensorineural hearing loss are at risk of cardiac electrophysiologic abnormalities. Inhalational Sevoflurane induction in these children can cause QT prolongation.

Objectives

In order to evaluate the safety of inhalational induction of anesthesia with sevoflurane in children with sensorineural hearing loss, who are candidates for cochlear implant, its electrophysiologic effects was compared with intravenous induction of anesthesia with propofol.

Methods

In this double-blind randomized clinical trial, 61 children aged between one and eighteen years old, who were candidates for cochlear implantation, were randomly allocated to groups receiving anesthesia with sevoflurane (n = 32) or propofol (n = 29) for induction of anesthesia. Two 12-leads ECG were taken from all of patients before and after induction and QTc, Tp-e interval, and JTc were measured and compared.

Results

Two cases, who had pre-induction QTc longer than 500 ms were excluded from the study. Patients had similar age (102.58 ± 87 versus 101.46 ± 67 months, P = 0.95) and gender (males: 48.3% versus 56.3%, P = 0.53) distribution. The researchers observed significant post induction difference in QTc values between these groups (propofol 422.5 ± 40, sevoflurane 445.0 ± 29, P = 0.016). There was no significant difference in the percent QTc and Tp-e changes in propofol and sevoflurane groups. Greater percentage of patients with increased Tp-e interval (> 100 ms) in the sevoflurane group than the propofol group was also seen. There was no significant long QTc difference (QTc > 500 ms or more than 60 ms increase from baseline) after induction of anesthesia in the sevoflurane group compared to the propofol group (15.6% versus 13.8%, P = 0.84).

Conclusions

After electrophysiological evaluations in children with sensorineural hearing loss, in patients whose pre-induction QTc is not longer than 500 ms, propofol seems safer than inhalational sevoflurane for induction of anesthesia.

Supramolecular therapeutics to treat the side effects induced by a depolarizing neuromuscular blocking agent

Succinylcholine (Sch) is the only depolarizing neuromuscular blocking agent widely used for rapid sequence induction in emergency rooms. Unfortunately, a variety of (sometimes lethal) adverse effects, such as hyperkalemia and cardiac arrest, are associated with its use, and currently there are no specific antidotes to reverse Sch or to treat these side-effects. Methods: The binding behaviors of Sch and several synthetic receptors, including cucurbit[7]uril, sulfo-calix[4]arene and water-soluble carboxylatopillar[6]arene (WP[6]), were first investigated. With a mouse model, a leathal dose of Sch was selected for evaluation of the antidotal effects of these synthetic receptors on Sch induced mortality. The antidotal effects of a selected synthetic receptor, WP[6], on Sch induced cardiac arrhythmias, hyperkalemia, rhabdomyolysis and paralysis were subsequently evaluated with rat and mouse models. The reversal mechanism was also investigated at a cellular level. Results: All of these macrocyclic molecules exhibited relatively high binding affinities with Sch in vitro. In a Sch-overdosed mouse model, immediate injection of these synthetic receptors right after Sch administration increased the overall survival rate, with WP[6] standing out with the most effective antidotal effects. In addition, administration of WP[6] also reversed the paralysis induced by Sch in a mouse model. Moreover, infusion of WP[6] to Sch-overdosed rats reduced the incidence of cardiac arrhythmia, inhibited the otherwise abnormally high serum potassium levels, and relieved the muscular damage. At the cellular level, WP[6] reversed the Sch induced depolarization and reduced the efflux of intracellular potassium. Conclusion: Synthetic receptors, particularly WP[6], exhibited high binding affinities towards Sch, and presented a significant potential as supramolecular therapeutics to treat the various side effects of Sch by specifically sequestering Sch in vivo.

A Comparison of the Effect of Sevoflurane and Propofol on Ventricular Repolarisation after Preoperative Cefuroxime Infusion

The aim of this study is to investigate the changes in QT, QTc, and Tp-e intervals and Tp-e/QT ratio on surface electrocardiogram (ECG) signals during anaesthesia induction using propofol or sevoflurane after preoperative cefuroxime infusion. Some 120 cases of gynaecological patients are randomly divided into propofol (P) and sevoflurane (S) groups (n=60). After cefuroxime (1.5 g) was infused in the two groups of patients, propofol target controlled infusion (TCI) was conducted in the P group for 5 min to realise a plasma concentration of 4 μg/ml while patients in the S group inhaled anaesthesia by infusing 1.3 MAC sevoflurane for 6 min. The 12-lead ECGs were separately collected before infusing cefuroxime (T₁), after infusing cefuroxime (T₂), and after infusing propofol or sevoflurane (T₃) to measure QT and Tp-e intervals, calculate QTc and Tp-e/QT, and record MAP and HR. Finally, we demonstrated that QT, QTc, and Tp-e intervals and Tp-e/QT ratio had no change (P > 0.05) after cefuroxime infusion in the two groups of patients compared with that before infusing antibiotics. Moreover, after conducting preoperative cefuroxime infusion, using propofol and sevoflurane had no influence on Tp-e interval, but sevoflurane can significantly prolong QT and QTc intervals (P < 0.05).

Effects of esmolol on QTc interval changes during tracheal intubation: a systematic review

INTRODUCTION AND AIMS

Esmolol is an ultra-short-acting β₁ antagonist that has been shown to attenuate the corrected QT (QTc) interval prolongation associated with laryngoscopy and endotracheal intubation (LTI). Prolongation of the QTc interval can precipitate arrhythmias, the most serious of which is torsades de pointes . The aim of this systematic review was to compare esmolol and placebo on QTc changes occurring during LTI.

MATERIALS AND METHODS

PubMed, EMBASE, Cochrane Registry of Clinical Trials and CINAHL databases (up to August 2018) were screened for randomised controlled trials comparing esmolol and placebo on QTc changes during LTI in cardiac and non-cardiac surgeries. The primary outcome was QTc changes during LTI and secondary outcome was related to adverse effects from esmolol such as bradycardia and hypotension.

RESULTS

Seven trials were identified involving 320 patients, 160 patients receiving esmolol or placebo apiece. A shortening of the QTc post-LTI was evident in the esmolol group compared with the placebo in four studies. Compared with the baseline, the QTc was reduced post-LTI in the esmolol group. In the placebo group, the QTc was prolonged compared with the baseline post LTI. Nonetheless, esmolol did not prevent QTc prolongation in the remaining three studies, and much of this was attributed to employing QTc prolonging agents for premedication and anaesthetic induction. No significant adverse events were noted.

CONCLUSION

Compared with placebo, esmolol reduced the LTI-induced QTc prolongation when current non-QTc prolonging agents were chosen for tracheal intubation. Future studies should explore whether transmural dispersion (a marker of torsadogenicity) is also affected during LTI by analysing parameters such as the Tp-e interval (interval between the peak to the end of the T-wave) and Tp-e/QTc (rate corrected Tp-e interval).

TRIAL REGISTRATION NUMBER

CRD42018090282.

Evaluation of the Effects of a Monthly Buprenorphine Depot Subcutaneous Injection on QT Interval During Treatment for Opioid Use Disorder

Extensive 12‐lead electrocardiogram monitoring and drug concentrations were obtained during development of BUP‐XR, a monthly subcutaneous injection for the treatment of opioid use disorder (OUD). Matched QT and plasma drug concentrations (11,925) from 1,114 subjects were pooled from 5 studies in OUD. A concentration‐QT model was developed, which accounted for confounding factors (e.g., comedications) affecting heart rate and heart rate‐corrected QT interval (QTc). Bias‐corrected nonparametric two‐sided 90% confidence intervals (CIs) were derived for the mean predicted effect of BUP‐XR on QTc (ΔQTc) at therapeutic and supratherapeutic doses. Changes in QTc were associated with age, central vs. noncentral reading, sex, methadone, and barbiturates. The upper 90% CI of ΔQTc was 0.29, 0.67, and 1.34 ms at the steady‐state peak concentration (C_max) for 100, 300, and 2 × 300 mg doses, respectively. An effect of BUP‐XR on QT can be ruled out at therapeutic and supratherapeutic doses of BUP‐XR, after accounting for covariates that may influence heart rate and QT interval in OUD.

Differential effects of sevoflurane and propofol on swine cardiac conduction system

OBJECTIVE

To compare the effects of sevoflurane and propofol on the porcine cardiac conduction system.

STUDY DESIGN

A prospective, comparative study of electrophysiological properties of anaesthetics agents in an experimental porcine model.

ANIMALS

A total of 36 hybrid Landrace-Large White pigs.

METHODS

After premedication with 20 mg kg^-1 of intramuscular ketamine, anaesthesia was induced with 4.5 mg kg^-1propofol intravenously. In 18 consecutive animals, anaesthesia was maintained with propofol (13 mg kg^-1 hour^-1) and in the remaining 18 animals with 2.66% sevoflurane. The femoral artery and vein were canalized for invasive monitoring, analytical blood gas sampling and intracardiac catheter insertion. Following instrumentation and after a period of stabilization, a customary electrophysiological evaluation was performed. We compared the electrophysiology of the sinus and atrioventricular node (AV) node under sevoflurane or propofol anaesthesia, and the effects of both anaesthetics on atrial and ventricular refractoriness.

RESULTS

There was a significant difference in sinus node recovery time between sevoflurane and propofol (907 ± 231 versus 753 ± 146 ms, p = 0.02). Sevoflurane in comparison with propofol significantly prolonged specialized AV conduction times, represented by an increased Wenckebach cycle length (272 ± 54 versus 235 ± 40 ms, p = 0.03) and AV nodal refractoriness (327 ± 34 versus 287 ± 30 ms, p = 0.002). In addition, sevoflurane prolonged ventricular refractoriness (298 ± 27 versus 255 ± 38 ms, p = 0.007) and the QT corrected interval (0.50 ± 0.05 versus 0.46 ± 0.09 ms, p = 0.005).

CONCLUSIONS AND CLINICAL RELEVANCE

Sevoflurane in comparison with propofol, depresses several parameters of sinus and AV nodal function and prolongs the ventricular refractoriness of the porcine cardiac conduction system. These findings should be taken into consideration for the choice of anaesthetic agents in clinical and experimental settings.

Perioperative management of patients with pre-excitation syndromes

Patients with pre-excitation abnormalities are at a high risk for life-threatening perioperative arrhythmias. In Wolff-Parkinson-White syndrome, the anaesthetics used for invasive diagnostic testing/ablation, should not affect cardiac electrophysiology; propofol, sevoflurane, fentanyl, sufentanil, alfentanil are suitable. In non-ablative surgery, propofol, sevoflurane, isoflurane, fentanyl, alfentanil, sufentanil have been used safely. Among neuromuscular blockers, cis-atracurium, rocuronium and vecuronium are good choices. Ketamine, pancuronium and pethidine should be avoided because of their sympathomimetic actions. Anticholinergic/ anticholinesterase combinations for neuromuscular block reversal should preferably be omitted, while sugammadex seems more attractive. In regional anaesthesia, addition of epinephrine and high sympathetic blocks should be avoided. Hypotension should be treated with pure alpha-adrenergic agonists. Other pre-excitation abnormalities associated with different accessory pathways are the Mahaim Fiber and Lown-Ganong-Levine syndrome. Sympathetic activation should be avoided. Total intravenous anaesthesia with propofol probably represents the safest option. A careful anaesthetic plan and close cooperation with cardiologists are mandatory for successful management.

Opioids and Cardiac Arrhythmia: A Literature Review

OBJECTIVE

One of the most important side effects of opioids is their influence on the electrical activity of the heart. This review focusses on the effects of opioids on QT interval prolongation and their arrhythmogenic liability.

METHODS

By using various keywords, papers published up to 2018 in different databases were searched and identified. The search terms were opioids names, corrected QT interval, human-ether-a-go-go gene, torsades de pointes (TdP), cardiac arrhythmias, opioid dependence and other relevant terms. It emphasized the effects of each opioid agent alone on electrocardiogram (ECG) and some interactions.

RESULTS

Available data indicate that some opioids such as methadone are high-risk even at low doses, and have potential for prolongation of the QT interval and development of TdP, a dangerous ventricular tachycardia. A number of opioids such as tramadol and oxycodone are intermediate risk drugs and may develop long QT interval and TdP in high doses. Some other opioids such as morphine and buprenorphine are low-risk drugs and do not produce QT interval prolongation and TdP at least in routine doses. Opium-consumers are at higher risk of supra-ventricular arrhythmias, sinus bradycardia, cardiac block and atrial fibrillation.

CONCLUSION

The cardiac arrhythmogenicity of various opioids is different. Methadone has a higher capability to induce long QT interval and dangerous arrhythmias in conventional doses than others. To reduce of arrhythmogenic risk, high doses of opioids must be used cautiously with periodic monitoring of ECG in high-risk consumers such as patients under opioid maintenance treatment.

The effects of intravenous anesthetics on QT interval during anesthetic induction with desflurane

Introduction

This study aimed to determine the effects of the interaction between intravenous anesthetics and desflurane on the QT interval.

Methods

Fifty patients who underwent lumbar spine surgery were included. The patients received 3 μg/kg fentanyl and were randomly divided into two groups: group P patients received 1.5 mg/kg propofol and group T patients received 5 mg/kg thiamylal 2 min after fentanyl injection. All patients received rocuronium and desflurane (6% inhaled concentration) after loss of consciousness. Tracheal intubation was performed 3 min after rocuronium injection. Heart rate (HR), mean arterial pressure (MAP), bispectral index score (BIS), and the heart rate-corrected QT (QTc) interval on a 12-lead electrocardiograms were recorded before fentanyl injection (T1), 2 min after fentanyl injection (T2), 1 min after propofol or thiamylal injection (T3), immediately before intubation (T4), and 2 min after intubation (T5).

Results

There were no significant intergroup differences in patient characteristics. BIS and MAP decreased after anesthesia induction in both groups. MAP values at T3, T4, and T5 in group T were higher than those in group P. HR did not change over time or differ between the groups. The QTc intervals at T4 and T5 in group T were longer than those at T1. In group P, the QTc interval at T3 was significantly shorter than that at T1. The QTc intervals at T3, T4, and T5 in group T were significantly longer than those in group P.

Conclusions

A propofol injection could counteract the QTc interval prolongation during desflurane anesthesia induction.

Trial registration

UMIN Clinical Trials Registry database reference number: UMIN000023707. This study was registered on August 21, 2016.

Effects of long periods of pneumoperitoneum combined with the head-up position on heart rate-corrected QT interval during robotic gastrectomy: an observational study

Objective

Pneumoperitoneum and the head-up position reportedly stimulate the sympathetic nervous system, potentially increasing the risk of cardiac arrhythmia. We evaluated the effects of a long duration of pneumoperitoneum in the head-up position on the heart rate-corrected QT (QTc) interval during robotic gastrectomy.

Methods

This prospective observational study involved 28 patients undergoing robotic gastrectomy. The QTc interval was recorded at the following time points: before anaesthetic induction (baseline); 10 minutes after tracheal intubation; 1, 5, 30, 60, and 90 minutes after pneumoperitoneum induction in the head-up position; after pneumoperitoneum desufflation in the supine position; and at the end of surgery. The primary outcome was the QTc interval, which was measured 90 minutes after pneumoperitoneum combined with the head-up position.

Results

Compared with baseline, the QTc interval was significantly prolonged at 1 and 60 minutes after pneumoperitoneum, peaked at 90 minutes, and was sustained and notably prolonged until the end of surgery. However, no considerable haemodynamic changes developed.

Conclusion

A long period of carbon dioxide pneumoperitoneum application in a head-up position significantly prolonged the QTc interval during robotic gastrectomy. Therefore, diligent care and close monitoring are required for patients who are susceptible to developing ventricular arrhythmia.

Trial Registration: Registered at ClinicalTrials.gov; https://clinicaltrials.gov/ct2/show/NCT02604979; Registration number NCT02604979

The effect of sevoflurane on the transmural dispersion of repolarisation in patients with type 2 diabetes mellitus: a prospective observational study

The 'torsadogenic' property of a drug is linked to its ability to increase the transmural dispersion of repolarisation, represented by the interval between the peak of, and the end of, the T-wave (Tp-e interval) in an electrocardiogram. Reports have consistently shown that sevoflurane does not increase the Tp-e interval. Type 2 diabetes is a risk factor for increased QTc (rate-corrected QT interval), QTcd (rate-corrected QTc dispersion: difference between the maximum and the minimum QTc interval), and Tp-e, as well as the rate-corrected Tp-e (Tp-e/QTc ratio). The study aimed to ascertain whether sevoflurane increased the Tp-e interval and Tp-e/QTc ratio in patients with diabetes, thereby increasing their risk of torsades. We enrolled 35 female patients; 17 with type 2 diabetes and 18 controls undergoing non-laparoscopic surgery under sevoflurane anaesthesia. The Tp-e interval, Tp-e/QTc ratio, QTc and QTcd were recorded after intubation, 5, 10, 30 and 60 minutes into the anaesthetic, and were compared between the groups. No significant increase in the Tp-e interval or Tp-e/QTc was observed between or within the groups (a 13 ms increase was considered significant). In the control group, the QTc was significantly increased from baseline immediately after intubation (449 versus 414 ms, <i>P</i> <0.001); at 5 minutes (434 versus 414 ms, <i>P</i>=0.01); at 10 minutes (444 versus 414 ms, <i>P</i>=0.002); at 30 minutes (439 versus 414 ms, <i>P</i>=0.001) and at 60 minutes (442 versus 414 ms; <i>P</i> <0.001) (a 20 ms increase was considered significant). No significant increase in QTc was observed in the diabetic group. There were no between or within group differences observed for QTcd. Our findings suggest that sevoflurane does not have a significant predictable pro-arrhythmic effect in type 2 diabetic patients in the absence of other factors affecting ventricular repolarisation.

Use of radiotelemetry to assess perinatal cardiac function in the ovine fetus and newborn

The late gestation fetal ECG (fECG) has traditionally been difficult to characterize due to the low fECG signal relative to high maternal noise. Although new technologies have improved the feasibility of its acquisition and separation, little is known about its development in late gestation, a period in which the fetal heart undergoes extensive maturational changes. Here, we describe a method for the chronic implantation of radiotelemetry devices into late gestation ovine fetuses to characterize parameters of the fECG following surgery, throughout late gestation, and in the perinatal period. We found no significant changes in mean aortic pressure (MAP), heart rate (HR), or ECG in the 5 days following implantation; however, HR decreased in the first 24 h following the end of surgery, with associated increases in RR, PR, and QRS intervals. Over the last 14 days of fetal life, fetal MAP significantly increased, and HR significantly decreased, as expected. MAP and HR increased as labor progressed. Although there were no significant changes over time in the ECG during late gestation, the duration of the PR interval initially decreased and then increased as birth approached. These results indicate that although critical maturational changes occur in the late gestation fetal myocardium, the mechanisms that control the cardiac conduction are relatively mature in late gestation. The study demonstrates that radiotelemetry can be successfully used to assess fetal cardiac function, in particular conduction, through the process of labor and delivery, and may therefore be a useful tool for study of peripartum cardiac events.