Update on Cardiovascular Implantable Electronic Devices for Anesthesiologists

Recombinant Adeno-Associated Viral Vector-Mediated Gene Transfer of hTBX18 Generates Pacemaker Cells from Ventricular Cardiomyocytes

Sinoatrial node dysfunction can manifest as bradycardia, leading to symptoms of syncope and sudden cardiac death. Electronic pacemakers are the current standard of care but are limited due to a lack of biological chronotropic control, cost of revision surgeries, and risk of lead- and device-related complications. We therefore aimed to develop a biological alternative to electronic devices by using a clinically relevant gene therapy vector to demonstrate conversion of cardiomyocytes into sinoatrial node-like cells in an in vitro context. Neonatal rat ventricular myocytes were transduced with recombinant adeno-associated virus vector 6 encoding either hTBX18 or green fluorescent protein and maintained for 3 weeks. At the endpoint, qPCR, Western blot analysis and immunocytochemistry were used to assess for reprogramming into pacemaker cells. Cell morphology and Arclight action potentials were imaged via confocal microscopy. Compared to GFP, hTBX18-transduced cells showed that hTBX18, HCN4 and Cx45 were upregulated. Cx43 was significantly downregulated, while sarcomeric α-actinin remained unchanged. Cardiomyocytes transduced with hTBX18 acquired the tapering morphology of native pacemaker cells, as compared to the block-like, striated appearance of ventricular cardiomyocytes. Analysis of the action potentials showed phase 4 depolarization and a significant decrease in the APD50 of the hTBX18-transduced cells. We have demonstrated that rAAV-hTBX18 gene transfer to ventricular myocytes results in morphological, molecular, physiological, and functional changes, recapitulating the pacemaker phenotype in an in vitro setting. The generation of these induced pacemaker-like cells using a clinically relevant vector opens new prospects for biological pacemaker development.

Pro-Con Debate: Are Patients With a Cardiovascular Implantable Electronic Device Suitable to Receive Care in a Free-Standing Ambulatory Surgery Center?

Migration of surgical and other procedures that require anesthesia care from a hospital to a free-standing ambulatory surgery center (ASC) continues to grow. Patients with cardiac implantable electronic devices (CIED) might benefit from receiving their care in a free-standing ASC setting. However, these patients have cardiovascular comorbidities that can elevate the risk of major adverse cardiovascular events. CIEDs are also complex devices and perioperative management varies between devices marketed by various manufacturers and require consultation and ancillary services, which may not be available in a free-standing ASC. Thus, perioperative care of these patients can be challenging. Therefore, the suitability of this patient population in a free-standing ASC remains highly controversial. Although applicable advisories exist, considerable discussion continues with surgeons and other proceduralists about the concerns of anesthesiologists. In this Pro-Con commentary article, we discuss the arguments for and against scheduling a patient with a CIED in a free-standing ASC.

The perioperative management of small animals with previously implanted pacemakers undergoing anaesthesia

OBJECTIVE

There is little information in the veterinary literature about the perioperative management of small animal patients with previously implanted pacemakers undergoing elective or emergency non-cardiac procedures. The purpose of this article is to review the current literature with regard to human patients, with previously implanted pacemakers, undergoing general anaesthesia. Using this and the current information on pacemakers and anaesthesia in dogs and cats, we provide recommendations for small animal patients in this situation.

DATABASES USED

Google Scholar, PubMed and CAB Abstracts using and interlinking and narrowing the search terms: "dog", "cat", "small animals", "anaesthesia", "pacemaker", "perioperative", "transvenous pacing", "temporary pacing". Scientific reports and human and small animal studies from the reference lists of the retrieved papers were reviewed. In addition, related human and veterinary cardiology and anaesthesia textbooks were also included to create a narrative review of the subject.

CONCLUSIONS

The best perioperative care for these animals comes from a multidisciplinary approach involving the anaesthetist, cardiologist, surgeon and intensive care unit team. When such an approach is not feasible, the anaesthetist should be familiar with pacemaker technology and how to avoid perioperative complications such as electromagnetic interference, lead damage and reprogramming of the device. The preanaesthetic assessment should be thorough. Information regarding the indication for pacemaker placement, complications during the procedure, location, type and programming of the pacemaker should be readily available. The anaesthetic management of these veterinary patients aims to preserve cardiovascular function while avoiding hypotension, and backup pacing should be available during the perioperative period. Further prospective studies are needed to describe the best perioperative care in small animals with a previously implanted pacemaker.

Evidence-Based Analysis of the Emergency Temporary Cardiac Pacing (Electrical Stimulation from Metal Wire Electrode)

The patient's Cr (creatinine), BUN (blood urea nitrogen), HBG (hemoglobin), VT (ventricular tachycardia), pacing frequency, puncture point, emergency to permanent pacing time, pacing current (mA), pacing threshold current (mA), and admission diagnosis data were collected. The data were subjected to frequency statistics, curve regression analysis, PLS regression analysis, adjustment analysis, chi-square test, ridge regression analysis, discriminant analysis, negative binomial regression analysis, Poisson regression analysis, and stepwise regression analysis. Some findings include the following: (1) Cr has a significant positive effect on HBG, and BUN has a significant negative effect on HBG. (2) VT has a negative correlation with age and a positive correlation with CK-MB and CK (creatinine kinase). (3) Myocarditis has a negative correlation with age and a significant positive correlation with CTnI (cardiac troponin I). (4) AST (aspartate transaminase) and ALT (alanine aminotransferase) have a significant positive impact on DDI (D-dimer), while CTnI has a significant negative impact on DDI. MYO (myoglobin) has no impact relationship to DDI. (5) ALT has a significant positive relationship with APTT (partial thromboplastin time). (6) Alb (albumin) and TBIL (total bilirubin) have a significant positive effect on PLT (platelet) count, while pro-BNP (B-type natriuretic peptide) and MYO have a significant negative effect on PLT. (7) CK has a significant positive effect on INR (international normalized ratio). (8) The relationship between sinus node dysfunction and VT significantly affect the pacing frequency (beats/minute). For third-degree atrioventricular block, different samples of sinus node dysfunction showed significant differences. (9) There is a significant positive correlation between pacing current (mA) and pacing threshold current (mA). (10) There was a significant positive correlation between perceived voltage (mV) and the time from emergency to permanent pacing. Admission diagnosis has a significant positive impact on the time from emergency to permanent pacing. The change (increase) in time from emergency to permanent pacing was 1.137-fold when an additional condition was diagnosed on admission.

Patient with an implantable cardiac electrical stimulation device. What should the anesthesiologist know?

Patients with implantable electric stimulation devices are challenging to the anesthesiologist since these cases demand a comprehensive knowledge about how the device operates, the indications for the implant and the implications that must be addressed during the perioperative period . This article is intended to provide the reader with clear and structured information so that the anesthesiologist will be able to safely deal with the situation of a patient with an implantable cardiac stimulation device, who has been programmed for emergent surgery. A search for the scientific evidence available was conducted in Pubmed / Medline, ScienceDirect, OVID, SciELO), for a non-systematic review. The incidence of the use of cardiac electric stimulation devices has been growing. Their operation is increasingly complex, and demands being constantly updated on the knowledge in the area.

Implementation of a Postoperative Electronic Health Record Alert for Cardiac Implantable Electronic Device Patients

PURPOSE

Approximately 2% of surgical patients have an existing cardiac implantable electronic device (CIED). Perioperative device reprogramming requires postoperative care to ensure that device settings are restored. Electronic health record (EHR) alerts have been shown to improve communication between providers and decrease time to necessary interventions in other areas of medicine. The aim of this quality improvement project was to create an EHR alert for postoperative CIED patients who require device reprogramming to help clinicians track, remember, and document the timely and safe restoration of device settings.

DESIGN

This project used a pre-post observational design.

METHODS

This project was conducted at a major academic medical center using a pre-post observational design. To prevent anesthesia providers from closing an encounter in the EHR before postoperative restoration of device settings, an alert was developed and embedded within the intraoperative EHR to track preoperative device reprogramming, and alert anesthesia providers to perform and document postoperative restoration of safe settings.

FINDINGS

The postimplementation group (n = 272) had fewer unknown or undocumented preoperative CIED interventions (12.9% vs 30.9%), a 7.3% shorter device suspension time (median = 165 minutes vs 178 minutes), 6.8% improvement in documentation of postoperative re-enabling of device therapies (78.8% vs 72.0%), and a 72.48% decrease in length of stay (median = 625 hours vs 172 hours) when compared with the preimplementation group (n = 132).

CONCLUSION

Electronic prompts effectively captured patients who received preoperative CIED reprogramming and provided a process for reprogramming devices to safe settings, both significant steps in preventing negative patient outcomes associated with undocumented CIED interventions. Perioperative CIED documentation improved, and length of stay decreased after project implementation.

Gene Therapy Approaches to Biological Pacemakers

Bradycardia arising from pacemaker dysfunction can be debilitating and life threatening. Electronic pacemakers serve as effective treatment options for pacemaker dysfunction. They however present their own limitations and complications. This has motivated research into discovering more effective and innovative ways to treat pacemaker dysfunction. Gene therapy is being explored for its potential to treat various cardiac conditions including cardiac arrhythmias. Gene transfer vectors with increasing transduction efficiency and biosafety have been developed and trialed for cardiovascular disease treatment. With an improved understanding of the molecular mechanisms driving pacemaker development, several gene therapy targets have been identified to generate the phenotypic changes required to correct pacemaker dysfunction. This review will discuss the gene therapy vectors in use today along with methods for their delivery. Furthermore, it will evaluate several gene therapy strategies attempting to restore biological pacing, having the potential to emerge as viable therapies for pacemaker dysfunction.

Comparison of perioperative strategies in ICD patients: The perioperative ICD management study (PIM study)

BACKGROUND

The prevalence of patients with implanted cardioverter defibrillators (ICDs) and the frequency of surgery on these patients are steadily on the rise. Guidelines recommend preoperative ICD reprogramming, although this is sometimes difficult in clinical practice. Placing a magnet on the ICD is a practical alternative and even no inactivation is possible in selected cases.

METHODS

In this prospective observational study, we compared different perioperative ICD management strategies depending on the location of the surgery and the type of electrocautery used. Patients undergoing surgery above the umbilicus with monopolar electrocautery had their ICD therapy inactivated by reprogramming. When surgery below the navel or surgery above the navel with bipolar electrocautery was completed, ICD inactivation was performed using a magnet. No inactivation was performed on patients undergoing lower extremity surgery with bipolar electrocautery. Only ICD patients who were not pacemaker dependent were enrolled. After surgery, the ICDs were assessed regarding documented arrhythmias and parameters.

RESULTS

Out of 101 patients included in this study, the ICD was preoperatively reprogrammed in 42 patients (41.6%), a magnet was used on 45 patients (44.5%), and ICDs were not deactivated at all in 14 patients (13.9%). No intraoperative electromagnetic interference was detected. Postoperative ICD analysis demonstrated no changes of preset parameters.

CONCLUSIONS

All three tested ICD management strategies were proved safe in this study. Keeping the location of surgery and the type of electrocautery in mind, an intraoperative magnet or even no ICD deactivation at all could be feasible alternatives in surgery on patients with ICDs.