Coronary periarteritis and pericarditis are rare but distinct manifestations of heart involvement in IgG4-related disease: a retrospective cohort study.

BACKGROUND: The heart can be involved in immunoglobulin (Ig)-G4-related disease (IgG4-RD). This study aimed to summarize the clinical features and efficacy of treatment for IgG4-RD patients with heart involvement. METHODS: We conducted a retrospective study enrolling 42 IgG4-RD patients with heart involvement from the IgG4-RD cohorts of the Peking Union Medical College Hospital and Beijing An Zhen Hospital, from 2010 to 2022. Clinical, laboratory, radiological data were collected, and treatment responses to glucocorticoids and immunosuppressants were analyzed. RESULTS: IgG4-related cardiac involvement is a rare part of the IgG4-RD spectrum. The incidences of coronary periarteritis and pericarditis were 1.2%(13/1075) and 3.1%(33/1075), respectively in our cohort. Valvular disease possibly related to IgG4-RD was detected in two patients. None of the patients with myocardial involvement were identified. The average age was 58.2 ± 12.8 years, with a male predominance (76.7%). Coronary artery CT revealed that mass-like and diffuse wall-thickening lesions were the most frequently observed type of coronary periarteritis. Pericarditis presented as pericardial effusion, localized thickening, calcification and mass. After treatment with glucocorticoid and immunosuppressants, all patients achieved a reduced IgG4-RD responder index score and achieved radiological remission. Two patients with coronary peri-arteritis experienced clinical relapses during the maintenance period. CONCLUSIONS: Cardiac involvement in IgG4-RD is rare and easily overlooked since many patients are asymptomatic, and the diagnosis relies on imaging. Patients showed a satisfactory response to glucocorticoid based treatment.

Unmasking the Unusual: Cryptococcal Pericarditis in a Patient with Liver Failure - a Rare Occurrence.

BACKGROUND Cryptococcosis is an invasive fungal infection caused by Cryptococcus species complex. C. neoformans is one of the pathogenic species within the genus. C. neoformans infections often present as an opportunistic infection in severely immunocompromised individuals. Infection of the pericardium in the setting of liver failure is uncommon. We present a case of cryptococcal pericarditis in a patient with liver failure. CASE REPORT A 47-year-old man with a past medical history of psoriatic arthritis, and alcohol use disorder presented to the emergency department with a 2-week history of progressively worsening generalized weakness, malaise, and yellowish skin changes. Physical examination revealed scleral icterus, jaundiced skin, and ascites. Initial laboratory workup revealed thrombocytopenia, transaminitis (aspartate transaminase (AST) level of 502 IU/L, alanine transaminase (ALT) level of 82 IU/L), hyperbilirubinemia (total bilirubin of 15.7 mg/dL), International Nationalized Ratio (INR) of 3.6, and lactic acidosis (lactic acid of 11.7 mmol/L). The patient developed encephalopathy and acute hypoxic respiratory failure requiring intubation. A bedside point-of-care cardiac ultrasound, performed following intubation, revealed a pericardial effusion without signs of tamponade. This finding was later confirmed by a formal transthoracic echocardiogram. Percutaneous pericardiocentesis was performed, and the pericardial fluid culture revealed the presence of C. neoformans. Human immunodeficiency virus (HIV) tests were negative. The patient received antifungal therapy. Due to his poor prognosis, he was transitioned to comfort care and eventually died. CONCLUSIONS This case report describes an unusual presentation of acute liver failure complicated by cryptococcal pericarditis, emphasizing the importance of considering atypical fungal infections in such patients.

Cardiac biomarkers as tools in the prediction and diagnosis of traumatic pericarditis and traumatic reticuloperitonitis in cattle and buffaloes.

BACKGROUND: In the livestock industry, Foreign Body Syndrome is a devastating disease condition. Feeding management, lacking of food discrimination, and eating chopped food increase the risk of swallowing sharp foreign bodies in bovine species. In addition to the honeycomb cells shape of the reticulum, the contractions of the reticular wall, gravid uterine pressure, and parturition efforts, foreign bodies can penetrate the reticular wall, causing cascade of problems including traumatic reticulitis, traumatic reticuloperitonitis, and traumatic pericarditis. The present study was carried out to evaluate the diagnostic significance of cardiac troponin I rapid test cassette and other cardiac biomarkers including serum cardiac troponin I (cTn I), creatine kinase-myocardial band (CK-MB), lactate dehydrogenase (LDH), and aspartate aminotransferase enzyme (AST), in confirmed cases of traumatic pericarditis (TP) and/or traumatic reticuleoperitonitis (TRP) in cattle and buffaloes. METHODS: A total number of 30 animals (22 cattle and 8 buffaloes) with different signs such as anorexia, jugular distension, brisket edema, and signs of pain (reluctance to move, arching back, and abduction of the forelimbs) were included in the present study. Based on case history, clinical signs, ferroscopic, pericardiocentesis, radiographic and ultrasonographic examinations, TP were confirmed in cattle (n = 10) and buffaloes (n = 8) while TRP were confirmed only in cattle (n = 12). Additionally, 20 clinically healthy animals (n = 10 cattle and 10 buffaloes) were used as a control group. Blood samples were collected for determination of blood level of Tn-I, and activity of CK-MB, LDH, and AST. RESULTS: The obtained results revealed a highly significant increase in serum cTn I in diseased cattle with TP and TRP (P = 0.00), while buffaloes with TP showed no significant changes in serum cTn I (P = 0.111). Both diseased cattle and buffaloes showed increased serum activities of CK-MB, AST, and LDH enzyme. On the other hand, cardiac troponin I rapid test cassette failed to detect cTn I in diseased animals. CONCLUSION: The study concluded that the cardiac troponin I rapid test cassette did not have a diagnostic significance and could not be used as a point-of-care under field condition for diagnosis of TP and TRP in large ruminants. However, the serum troponin I level is helpful in diagnosis of TP and TRP in cattle. Although cardiac biomarkers have some diagnostic values in TP and TRP, the traditional diagnostic methods (clinical, radiography and ultrasonography examinations) are crucial for thorough evaluation of TP/TRP cases in bovine.

Cardiovascular Safety of COVID-19 Vaccination in Patients With Cancer: A Self-Controlled Case Series Study in Korea.

BACKGROUND: Cancer patients have an increased risk of cardiovascular outcomes and are susceptible to coronavirus disease 2019 (COVID-19) infection. We aimed to assess the cardiovascular safety of COVID-19 vaccination for cancer patients in South Korea. METHODS: We conducted a self-controlled case series study using the K-COV-N cohort (2018-2021). Patients with cancer aged 12 years or older who experienced cardiovascular outcomes were identified. Cardiovascular outcomes were defined as myocardial infarction, stroke, venous thromboembolism (VTE), myocarditis, or pericarditis, and the risk period was 0-28 days after receiving each dose of COVID-19 vaccines. A conditional Poisson regression model was used to calculate the incidence rate ratio (IRR) with 95% confidence interval (CI). RESULTS: Among 318,105 patients with cancer, 4,754 patients with cardiovascular outcomes were included. The overall cardiovascular risk was not increased (adjusted IRR, 0.99 [95% CI, 0.90-1.08]) during the whole risk period. The adjusted IRRs of total cardiovascular outcomes during the whole risk period according to the vaccine type were 1.07 (95% CI, 0.95-1.21) in the mRNA vaccine subgroup, 0.99 (95% CI, 0.83-1.19) in the ChAdOx1 nCoV-19 vaccine subgroup, and 0.86 (95% CI, 0.68-1.10) in the mix-matched vaccination subgroup. However, in the analysis of individual outcome, the adjusted IRR of myocarditis was increased to 11.71 (95% CI, 5.88-23.35) during the whole risk period. In contrast, no increased risk was observed for other outcomes, such as myocardial infarction, stroke, VTE, and pericarditis. CONCLUSION: For cancer patients, COVID-19 vaccination demonstrated an overall safe profile in terms of cardiovascular outcomes. However, caution is required as an increased risk of myocarditis following COVID-19 vaccination was observed in this study.

Global estimates on the reports of vaccine-associated myocarditis and pericarditis from 1969 to 2023: Findings with critical reanalysis from the WHO pharmacovigilance database.

Due to the limitation of previous studies examining adverse reports of myocarditis and pericarditis associated with vaccines other than the COVID-19 vaccine, there are challenges in establishing a comprehensive understanding of vaccine safety on a global scale. Hence, the objective of this study was to examine the worldwide burden of vaccine-associated pericarditis and myocarditis and the vaccines associated with these indications. This study utilized the World Health Organization international pharmacovigilance database, from which records of vaccine-associated pericarditis and myocarditis between 1969 and 2023 were extracted (over 130 million reports). We calculated global reporting counts, reported odds ratios (RORs), and information components (ICs) to discern the association between 19 vaccines and the occurrence of pericarditis and myocarditis across 156 countries and territories. We identified 49 096 reports (male, n = 30 013) of vaccine-associated pericarditis and myocarditis among 73 590 reports of all-cause pericarditis and myocarditis. There has been a significant increase in reports of vaccine-related cardiac adverse events over time, with a noteworthy surge observed after 2020, attributed to cases of pericarditis associated with COVID-19 mRNA vaccines. Smallpox vaccines were associated with most pericarditis and myocarditis reports (ROR: 73.68 [95% CI, 67.79-80.10]; IC [IC0.25]: 6.05 [5.91]), followed by COVID-19 mRNA vaccine (37.77 [37.00-38.56]; 3.07 [3.05]), anthrax vaccine (25.54 [22.37-29.16]; 4.58 [4.35]), typhoid vaccine (6.17 [5.16-7.38]; 2.59 [2.29]), encephalitis vaccine (2.00 [1.48-2.71]; 0.99 [0.47]), influenza vaccine (1.87 [1.71-2.04]; 0.90 [0.75]), and Ad5-vectored COVID-19 vaccine (1.40 [1.34-1.46]; 0.46 [0.39]). Concerning age and sex-specific risks, reports of vaccine-associated pericarditis and myocarditis were more prevalent among males and in older age groups. The age group between 12 and 17 years exhibited significant sex disproportion. Most of these adverse events had a short time to onset (median time: 1 day) and fatality rate was 0.44%. Our analysis of global data revealed an increase in pericarditis and myocarditis reports associated with vaccines, particularly live vaccines like smallpox and anthrax, notably in young males. While these adverse events are generally rare and mild, caution is warranted, especially for healthcare workers, due to potential myocardial injury-related in-hospital mortality. Further study with validated reporting is crucial to enhance accuracy in evaluating the correlation between vaccines and cardiac conditions for preventive measures.

Acute Pericarditis: Rapid Evidence Review.

Acute pericarditis is defined as inflammation of the pericardium and occurs in approximately 4.4% of patients who present to the emergency department for nonischemic chest pain, with a higher prevalence in men. Although there are numerous etiologies of pericarditis, most episodes are idiopathic and the cause is presumed to be viral. Diagnosis of pericarditis requires at least two of the following criteria: new or worsening pericardial effusion, characteristic pleuritic chest pain, pericardial friction rub, or electrocardiographic changes, including new, widespread ST elevations or PR depressions. Pericardial friction rubs are highly specific but transient, and they have been reported in 18% to 84% of patients with acute pericarditis. Classic electrocardiographic findings include PR-segment depressions; diffuse, concave, upward ST-segment elevations without reciprocal changes; and T-wave inversions. Transthoracic echocardiography should be performed in all patients with acute pericarditis to characterize the size of effusions and evaluate for complications. Nonsteroidal anti-inflammatory drugs are the first-line treatment option. Glucocorticoids should be reserved for patients with contraindications to first-line therapy and those who are pregnant beyond 20 weeks' gestation or have other systemic inflammatory conditions. Colchicine should be used in combination with first- or second-line treatments to reduce the risk of recurrence. Patients with a higher risk of complications should be admitted to the hospital for further workup and treatment.

Cardiovascular toxicity of immune therapies for cancer.

In addition to conventional chemoradiation and targeted cancer therapy, the use of immune based therapies, specifically immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T cell therapy (CAR-T), has increased exponentially across a wide spectrum of cancers. This has been paralleled by recognition of off-target immune related adverse events that can affect almost any organ system including the cardiovascular system. The use of ICIs has been associated with myocarditis, a less common but highly fatal adverse effect, pericarditis and pericardial effusions, vasculitis, thromboembolism, and potentially accelerated atherosclerosis. CAR-T resulting in a systemic cytokine release syndrome has been associated with myriad cardiovascular consequences including arrhythmias, myocardial infarction, and heart failure. This review summarizes the current state of knowledge regarding adverse cardiovascular effects associated with ICIs and CAR-T.

Assessment of Radiation Induced Pneumonitis and Pericarditis in Patients Undergoing Breast Conservative Treatment Using Hypofractionated Simultaneous Integrated Boost Technique.

INTRODUCTION: To determine the proportion of radiationinduced pneumonitis and pericarditis in patients who have received Hypo-fractionated Radiation along with simultaneous integrated boost technique after breast conservative surgery using a prospective observational study from a tertiary hospital. MATERIALS & METHODS: The incidence of radiationinduced pneumonitis and pericarditis was evaluated in all adult patients with biopsy-proven early-stage unilateral breast cancer who underwent breast-conserving surgery followed by hypo-fractionated radiation with a simultaneous integrated boost technique. Baseline assessments including a six-minute walk test, highresolution computed tomography (HRCT), pulmonary function tests (PFTs), electrocardiography (ECG) and echocardiography (ECHO) were performed. At three months post-radiation treatment, patients underwent follow-up assessments with a six-minute walk test, ECG and ECHO. At six months post-radiation treatment, patients underwent further assessments with a six-minute walk test, ECG, ECHO, PFTs, and HRCT of the thorax. Data analysis was performed using SPSS version 19. RESULTS: Our study investigated the incidence of acute radiation-induced pneumonitis and pericarditis in patients treated with hypofractionated VMAT-SIB technique in 20 eligible early breast cancer patients. The study found that the technique is feasible and achieves encouraging dosimetric parameters, including well achieved ipsilateral lung and heart doses. The reduced treatment time of 3-4 weeks compared to the previous 6-7 weeks with sequential boost was also found to be desirable in resource-constrained settings. The incidence of acute radiation pneumonitis and pericarditis was acceptable and comparable to existing data, with 90% of patients experiencing grade 1 radiation pneumonitis according to CTCAE v5.0. Post-treatment pulmonary function tests showed significant changes, particularly in patients who had received neoadjuvant chemotherapy and nodal irradiation. The six-minute walk test and Borg scale also showed a significant positive correlation with pulmonary function tests. There was no significant pericarditis during the follow-up. The study proposes that the hypofractionated radiotherapy using VMAT-SIB is a suitable alternative to conventional fractionation, with acceptable acute toxicities, but longer follow-up is required to assess the impact on late toxicities. CONCLUSION: Our research has shown that hypofractionated adjuvant radiotherapy with SIB is a safe and feasible treatment for patients with early breast cancer. This treatment method doesn't pose any significant short-term risks to the lungs or heart, and the SIB technique provides better coverage, conformity and sparing of organs at risk. Additionally, patients have reported positive cosmetic outcomes with this treatment. However, to make more accurate conclusions, we need to conduct further studies with larger sample sizes and longer follow-up periods to evaluate the potential longterm side effects of this treatment using VMAT in whole breast radiation.

Efficacy and Safety of Interleukin-1 Inhibitors in the Management of Patients with Recurrent Pericarditis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: The efficacy and safety of interleukin-1 (IL-1) inhibitors in patients with recurrent pericarditis (RP) remain to be determined. OBJECTIVE: We aimed to conduct a meta-analysis to investigate the impact of IL-1 inhibitors on patients suffering from RP. METHODS: The Cochrane Library, PubMed, EMBASE, ClinicalTrials.gov, and Web of Science databases were systematically searched to identify articles investigating the effects of IL-1 inhibitors in patients with RP up until January 2024. Relevant data on study characteristics and results were selected based on predefined criteria. The results were combined using a random effects model. RESULTS: The study included a total of 102 patients from three open-label randomized controlled trials. Overall, the use of IL-1 inhibitors, in comparison to placebo, demonstrated a significant reduction in the risk of pericarditis recurrence [risk ratio (RR) 0.13; 95% confident interval (CI) 0.05-0.30; p < 0.05; I2 = 0%]. However, the administration of IL-1 inhibitors may lead to certain adverse events (AEs), including infections and injection-site reactions. The risk of AEs is significantly higher with IL-1 inhibitors compared with placebo (RR 1.88; 95% CI 1.30-2.72; p < 0.05; I2 = 0%). Nevertheless, the occurrence of serious AEs among patients was relatively rare, and no fatalities were reported. CONCLUSION: This meta-analysis showed that IL-1 inhibitors can effectively reduce the risk of recurrence in patients with RP and are relatively safe. REGISTRATION: PROSPERO identifier number CRD42023492904.

Purulent Pericarditis as the First Manifestation of Esophageal Carcinoma.

INTRODUCTION: Purulent pericarditis secondary to esophago-pericardial fistula is a serious complication that has been previously reported in patients with esophageal cancer treated with radio/chemotherapy and esophageal stenting. However, the presence of esophago-pericardial fistula as the first manifestation of advanced carcinoma of the esophagus is exceedingly infrequent. We report the case of a 61-year-old male who presented with sepsis, cardiac tamponade and septic shock who was found to have an esophago-pericardial fistula secondary to squamous carcinoma of the esophagus. Emergency pericardiocentesis was performed with subsequent hemodynamic improvement. The drained pericardial fluid was purulent in nature and cultures were positive for Streptococcus anginosus. A CT scan followed by upper gastrointestinal endoscopy with tissue biopsy confirmed the diagnosis of squamous cell carcinoma of the esophagus. A self-expanding covered stent was endoscopically placed to exclude the fistula and restore the esophageal lumen. In this report, we discuss some aspects related to the diagnosis and management of this serious clinical entity.

Symptomatic Pericardial Effusion Associated With Graves' Disease in a Pediatric Patient.

Pericarditis is a well-known complication of hypothyroidism. Although pericarditis and pericardial effusions have been reported as rare complications of hyperthyroidism in adults, they are rarely reported in the pediatric population. In this case report, we describe a 12-year-old, previously healthy girl with nighttime chest pain, dyspnea, tachycardia, and abnormal thyroid function studies consistent with hyperthyroidism who was found to have pericarditis and pericardial effusion requiring pericardiocentesis.

Acute and Complicated Inflammatory Pericarditis: A Guide to Contemporary Practice.

Inflammatory disease of the pericardium represents a relatively common presentation, especially among the young. For the most part, inflammatory pericardial disease can be expeditiously and effectively managed without significant sequelae. However, some individuals present with severe and recurrent illness, representing significant therapeutic challenges. During the past decade, there have been great strides made in developing an evidence-based approach to management of inflammatory pericardial disease, the result of which has been the development of (1) a systematic, protocoled approach to initial care; (2) targeted therapeutics; and (3) specialized, collaborative, and integrated care pathways. Herein we present a review of the current state of the art as it pertains to the diagnostic evaluation and therapeutic considerations in inflammatory pericardial disease with a focus on acute and complicated pericarditis.

Atrial Fibrosis and Inflammation in Postoperative Atrial Fibrillation: Comparative Effects of Amiodarone, Colchicine, or Exosomes.

BACKGROUND: Extracellular vesicles (EVs) isolated from human heart-derived cells have shown promise in suppressing inflammation and fibroblast proliferation. However, their precise benefits in atrial fibrillation (AF) prevention and the role of their antifibrotic/anti-inflammatory properties remain unclear. OBJECTIVES: The purpose of this study was to conduct a head-to-head comparison of antiarrhythmic strategies to prevent postoperative AF using a rat model of sterile pericarditis. Specifically, we aimed to assess the efficacy of amiodarone (a classic antiarrhythmic drug), colchicine (an anti-inflammatory agent), and EVs derived from human heart-derived cells, which possess anti-inflammatory and antifibrotic properties, on AF induction, inflammation, and fibrosis progression. METHODS: Heart-derived cells were cultured from human atrial appendages under serum-free xenogen-free conditions. Middle-aged Sprague Dawley rats were randomized into different groups, including sham operation, sterile pericarditis with amiodarone treatment, sterile pericarditis with colchicine treatment (2 dose levels), and sterile pericarditis with intra-atrial injection of EVs or vehicle. Invasive electrophysiological testing was performed 3 days after surgery before sacrifice. RESULTS: Sterile pericarditis increased the likelihood of inducing AF. Colchicine and EVs exhibited anti-inflammatory effects, but only EV treatment significantly reduced AF probability, whereas colchicine showed a positive trend without statistical significance. EVs and high-dose colchicine reduced atrial fibrosis by 46% ± 2% and 26% ± 2%, respectively. Amiodarone prevented AF induction but had no effect on inflammation or fibrosis. CONCLUSIONS: In this study, both amiodarone and EVs prevented AF, whereas treatment with colchicine was ineffective. The additional anti-inflammatory and antifibrotic effects of EVs suggest their potential as a comprehensive therapeutic approach for AF prevention, surpassing the effects of amiodarone or colchicine.

Medical therapy of pericarditis: tips and tricks for clinical practice.

Medical therapy of pericarditis should be targeted at its aetiology. Unfortunately, many cases of pericarditis remain idiopathic after a complete diagnostic workup. In such cases, empiric anti-inflammatory therapy for pericarditis is aimed at controlling symptoms and preventing recurrences. The aim of the present clinical review is to summarize published evidence, guidelines, and to provide tips and tricks for clinical management of acute and recurrent pericarditis.

Characterization of Brighton Collaboration criteria for myocarditis and pericarditis following COVID-19 vaccine in Korean adolescents.

BACKGROUND: Vaccines are vital for public health, but concerns about adverse effects, particularly myocarditis and pericarditis linked to COVID-19 vaccines-, persist. This study investigates the application of Brighton Collaboration case definition to national vaccine safety data related to post-COVID-19 vaccine myo/pericarditis, utilizing claims under the Korea National Vaccine Injury Compensation Program (NIVCP). METHODS: This study analyzed 190 medical records of individuals who claimed to have developed myo/pericarditis after receiving the COVID-19 vaccine, as reported to the NVICP between specified dates, categorizing cases based on the Brighton criteria for myocarditis or pericarditis. RESULTS: Between 2021-2022, NVICP received 190 cases meeting the Brighton criteria for myocarditis or pericarditis at levels 1, 2, or 3. Most cases fell into Level 2 (70%), followed by Level 1 (29%), and one at Level 3 (1%), with Level 1 cases showing a higher hospitalization rate (87.3%) and a notable proportion requiring admission to the Intensive Care Unit (25.5%). Chest pain and Troponin-I/T elevation were common findings in Level 1 cases, while Level 2 cases exhibited similar patterns but at a slightly lower frequency. Electrocardiogram and echocardiography findings differed between the two levels. CONCLUSION: The Brighton Collaboration case definition proved valuable for classifying and assessing AEFI data, enhancing our understanding of the potential relationship between myocarditis and the COVID-19 vaccine.

Comparative safety profile of bivalent and original COVID-19 mRNA vaccines regarding myocarditis/pericarditis: A pharmacovigilance study.

OBJECTIVES: Bivalent COVID-19 mRNA vaccines, which contain two different components, were authorized to provide protection against both the original strain of SARS-CoV-2 and the Omicron variant as a measure to address the COVID-19 pandemic. Concerns regarding the risk of myocarditis/pericarditis associated with bivalent vaccination have been raised due to the observed superior neutralizing antibody responses. This study aimed to investigate the risk of myocarditis/pericarditis following bivalent COVID-19 mRNA vaccination compared to monovalent vaccination. METHODS: The CDC COVID Data Tracker and the Vaccines Adverse Event Reporting System (VAERS) were analyzed between December 13, 2020 to March 8, 2023. Reporting rates were determined by dividing the number of myocarditis/pericarditis cases by the total number of vaccine doses administered. Disproportionality patterns regarding myocarditis/pericarditis were evaluated for various COVID-19 mRNA vaccinations using reporting odds ratios (RORs). RESULTS: The reporting rate for myocarditis/pericarditis following original monovalent COVID-19 mRNA vaccination was 6.91 (95 % confidence interval [95 %CI] 6.71-7.12) per million doses, while the reporting rate for bivalent vaccination was significantly lower (1.24, 95%CI 0.96-1.58). Disproportionality analysis revealed a higher reporting of myocarditis/pericarditis following original vaccination with a ROR of 2.21 (95 %CI 2.00-2.43), while bivalent COVID-19 mRNA vaccination was associated with fewer reports of myocarditis/pericarditis (ROR 0.57, 95 %CI 0.45-0.72). Sub-analyses based on symptoms, sex, age and manufacturer further supported these findings. CONCLUSION: This population-based study provides evidence that bivalent COVID-19 mRNA vaccination is not associated with risk of myocarditis/pericarditis. These findings provide important insights into the safety profile of bivalent COVID-19 mRNA vaccines and support their continued use as updated boosters.