Epicardial injection of nanoformulated calcium into cardiac ganglionic plexi suppresses autonomic nerve activity and postoperative atrial fibrillation

Pericardial Inflammatory Mediators That Can Drive Postoperative Atrial Fibrillation in Cardiac Surgery Patients

Postoperative atrial fibrillation (POAF) is a common dysrhythmia that affects a significant number of patients undergoing cardiac surgery. Many studies aim to better understand this complex postsurgical complication by analysing circulating biomarkers in patients who develop POAF. More recently, the pericardial space was shown to contain inflammatory mediators that could trigger POAF. In this review we summarise recent studies that examine the immune mediators present in the pericardial space and their potential implications for the pathophysiology of POAF in cardiac surgery patients. Ongoing research in this area should better delineate the multifactorial etiology of POAF, where specific markers may be targeted to reduce the incidence of POAF and improve outcomes for this patient population.

Neuromodulation therapy for atrial fibrillation

Atrial fibrillation has a multifactorial pathophysiology influenced by cardiac autonomic innervation. Both sympathetic and parasympathetic influences are profibrillatory. Innovative therapies targeting the neurocardiac axis include catheter ablation or pharmacologic suppression of ganglionated plexi, renal sympathetic denervation, low-level vagal stimulation, and stellate ganglion blockade. To date, these therapies have variable efficacy. As our understanding of atrial fibrillation and the cardiac nervous system expands, our approach to therapeutic neuromodulation will continue evolving for the benefit of those with AF.

Nano drugs delivery system: A novel promise for the treatment of atrial fibrillation

Atrial fibrillation (AF) is one of the most common sustained tachyarrhythmias worldwide, and its prevalence is positively correlated with aging. AF not only significantly reduces the quality of life of patients but also causes a series of complications, such as thromboembolism, stroke, and heart failure, increases the average number of hospitalizations of patients, and places a huge economic burden on patients and society. Traditional drug therapy and ablation have unsatisfactory success rates, high recurrence rates, and the risk of serious complications. Surgical treatment is highly traumatic. The nano drug delivery system has unique physical and chemical properties, and in the application of AF treatment, whether it is used to assist in enhancing the ablation effect or for targeted therapy, it provides a safer, more effective and more economical treatment strategy.

Derivation and Validation of a Clinical Score for Predicting Postoperative Atrial Fibrillation in Noncardiac Elective Surgery (the HART Score)

Postoperative atrial fibrillation (POAF) represents the most frequent cardiac arrhythmia in the surgical setting. It affects almost 3% of all patients over 45 years old who underwent noncardiovascular surgery and is associated with a higher risk of stroke, heart failure, myocardial infarction, and cardiac arrest. The study aimed to assess independent predictors of POAF and derive and validate a score for risk prediction in clinical practice. This was a retrospective cohort study including all consecutive candidates to all types of noncardiac elective surgery attending a cardiological preoperative assessment from 2016 to 2019. Exclusion criteria were a previous diagnosis of AF and the cancelation of the planned surgery. A total of 2,048 patients were enrolled (1350 men, aged 72 ± 12 years). A total of 44 patients experienced POAF (2.1%) - median 3 days (first to third quartile 2 to 4 days). Age (odds ratio [OR] 1.03 for each year, 95% confidence interval [CI] 1.01 to 1.07), hypertension (OR 3.43, 95% CI 1.22 to 9.63), thyroid dysfunction (OR 2.47, 95% CI 1.22 to 5.01), and intermediate or high-risk surgery (OR 18.28, 95% CI 2.51 to 33.09) resulted as independent predictors of POAF (all p <0.05). The Hypertension, Age, surgery Risk, and Thyroid dysfunction score (OR 2.59 for each point, 95% CI 1.79 to 3.75, p <0.001) was then created based on those 4 items. A cut-off score ≥6 had a 70% sensitivity and a 72% specificity in detecting POAF (area under the curve 0.76). Bootstrapping for internal validation confirmed the overall results (area under the curve 0.72). In conclusion, POAF complicates around 2% of all noncardiac surgery. A 4-item risk score, such as the Hypertension, Age, surgery Risk, and Thyroid dysfunction score, could be effective in implementing POAF screening and improving management.

Autonomic Neuromodulation for Atrial Fibrillation Following Cardiac Surgery: JACC Review Topic of the Week

Autonomic neuromodulation therapies (ANMTs) (ie, ganglionated plexus ablation, epicardial injections for temporary neurotoxicity, low-level vagus nerve stimulation [LL-VNS], stellate ganglion block, baroreceptor stimulation, spinal cord stimulation, and renal nerve denervation) constitute an emerging therapeutic approach for arrhythmias. Very little is known about ANMTs' preventive potential for postoperative atrial fibrillation (POAF) after cardiac surgery. The purpose of this review is to summarize and critically appraise the currently available evidence. Herein, the authors conducted a systematic review of 922 articles that yielded 7 randomized controlled trials. In the meta-analysis, ANMTs reduced POAF incidence (OR: 0.37; 95% CI: 0.25 to 0.55) and burden (mean difference [MD]: -3.51 hours; 95% CI: -6.64 to -0.38 hours), length of stay (MD: -0.82 days; 95% CI: -1.59 to -0.04 days), and interleukin-6 (MD: -79.92 pg/mL; 95% CI: -151.12 to -8.33 pg/mL), mainly attributed to LL-VNS and epicardial injections. Moving forward, these findings establish a base for future larger and comparative trials with ANMTs, to optimize and expand their use.

Role and mechanism of lncRNA under magnetic nanoparticles in atrial autonomic nerve remodeling during radiofrequency ablation of recurrent atrial fibrillation

It aimed to investigate the mechanism of magnetic nanoparticles (MNPs) on atrial fibrillation and effect of n-isopropyl acrylamide coated MNPs (NIPA-co-MN) on the treatment of atrial fibrillation. Ten beagles weighing 20 - 25 kg were randomly divided into test group and control group. Dogs with atrial fibrillation were set as test group, and non-atrial fibrillation dogs as control group. The expression of long non-coding RNA (lncRNA) differentially expressed in the right anterior adipose pad in atrial fibrillation and non-atrial fibrillation dogs was detected by high-throughput sequencing. The relationship between lncRNA and cardiac autonomic nerve remodeling (CANR) was explored. In addition, 20 beagles weighing 20-25 kg were selected to study the therapeutic effect of n-isopropylacrylamide magnetic nanoparticles (NIPA-co-MN) on atrial fibrillation, and statistical analysis was performed. The volume and number of new neurons in the anterior right fat pad of atrium of test group were larger than the control group. The test group dogs produced 45 brand-new lncRNA, including 15 up-regulated transcripts and 30 down-regulated transcripts. MNPs injection can slow down the reduction of ventricular rate in right inferior ganglion plexus. The anterior right ganglion plexus resulted in a reduced amplitude of sinus tachyarrhythmia. This study provided references for the discovery of new diagnostic biomarkers or therapeutic targets and for the treatment of patients with atrial fibrillation.

Neuroscientific therapies for atrial fibrillation

The cardiac autonomic nervous system (ANS) plays an integral role in normal cardiac physiology as well as in disease states that cause cardiac arrhythmias. The cardiac ANS, comprised of a complex neural hierarchy in a nested series of interacting feedback loops, regulates atrial electrophysiology and is itself susceptible to remodelling by atrial rhythm. In light of the challenges of treating atrial fibrillation (AF) with conventional pharmacologic and myoablative techniques, increasingly interest has begun to focus on targeting the cardiac neuraxis for AF. Strong evidence from animal models and clinical patients demonstrates that parasympathetic and sympathetic activity within this neuraxis may trigger AF, and the ANS may either induce atrial remodelling or undergo remodelling itself to serve as a substrate for AF. Multiple nexus points within the cardiac neuraxis are therapeutic targets, and neuroablative and neuromodulatory therapies for AF include ganglionated plexus ablation, epicardial botulinum toxin injection, vagal nerve (tragus) stimulation, renal denervation, stellate ganglion block/resection, baroreceptor activation therapy, and spinal cord stimulation. Pre-clinical and clinical studies on these modalities have had promising results and are reviewed here.

Calcium-Induced Autonomic Denervation in Patients With Post-Operative Atrial Fibrillation

BACKGROUND

Post-operative atrial fibrillation (POAF) is associated with worse long-term cardiovascular outcomes.

OBJECTIVES

This study hypothesized that injecting calcium chloride (CaCl₂) into the major atrial ganglionated plexi (GPs) during isolated coronary artery bypass grafting (CABG) can reduce the incidence of POAF by calcium-induced autonomic neurotoxicity.

METHODS

This proof-of-concept study randomized 200 patients undergoing isolated, off-pump CABG to CaCl₂ (n = 100) or sodium chloride (sham, n = 100) injection. Two milliliters of CaCl₂ (5%) or sodium chloride (0.9%) was injected into the 4 major atrial GPs during CABG. All patients received 7-day continuous telemetry and Holter monitoring. The primary outcome was incidence of POAF (≥30 s) in 7 days. Secondary outcomes included length of hospitalization, POAF burden, average ventricular rate during AF, plasma level of inflammatory markers, and actionable antiarrhythmic therapy to treat POAF.

RESULTS

The POAF incidence was reduced from 36% to 15% (hazard ratio: 0.366; 95% confidence interval: 0.211 to 0.635; p = 0.001). Length of hospitalization did not differ between the 2 groups. POAF burden (first 7 post-operative days), the use of amiodarone or esmolol, and the incidence of atrial couplets and nonsustained atrial tachyarrhythmias were significantly reduced in the CaCl₂ group. Heart rate variability data showed a decrease in both high-frequency and low-frequency power in the CaCl₂ group with a preserved low-frequency/high-frequency ratio, suggesting that the sympathetic/parasympathetic balance was not perturbed by CaCl₂ injection.

CONCLUSIONS

Injection of CaCl₂ into the 4 major atrial GPs reduced the POAF hazard by 63%. Inhibition of GP function by Ca-mediated neurotoxicity may underlie the therapeutic effect. (Calcium Autonomic Denervation Prevents Postoperative Atrial Fibrillation; ChiCTR1800019276).

Therapeutic advances in cardiac targeted drug delivery: from theory to practice

The most commonly used administration methods in clinics and life are oral administration, intravenous injection, and other systemic administration methods. Targeted administration must be an essential long-term development direction due to the limited availability and a high incidence of systemic side effects. Cardiovascular diseases (CVD) are the leading cause of death all over the world. Targeted drug delivery (TDD) methods with the heart as the target organ have developed rapidly and are diversified. This article reviews the research progress of various TDD methods around the world with a heart as the target organ. It is mainly divided into two parts: the targeting vector represented by nanoparticles and various TDD methods such as intracoronary injection, ventricular wall injection, pericardial injection, and implantable medical device therapy and put forward some suggestions on the development of targeting. Different TDD methods described in this paper have not been widely used in clinical practice, and some have not even completed preclinical studies. Targeted drug delivery still requires long-term efforts by many researchers to realize the true meaning of the heart. HIGHLIGHTS Targeted administration can achieve a better therapeutic effect and effectively reduce the occurrence of adverse reactions. Parenteral administration or medical device implantation can be used for targeted drug delivery. Combined with new dosage forms or new technologies, better-targeted therapy can be achieved. Clinical trials have confirmed the safety and effectiveness of several administration methods.