Endomyocardial biopsy findings in 50 patients with idiopathic atrioventricular block: presence of myocarditis

COVID-19 BBIBP-CorV vaccine and transient heart block - A phenomenon by chance or a possible correlation - A case report

IMPORTANCE

Bradyarrhythmia during COVID19 illness carries prognostic significance. Electrophysiological side effects of COVID19 vaccine remain largely unknown. It is imperative to report nature of cardiovascular side effects of the vaccine.

CASE PRESENTATION

An 80 years-old-man presented with complains of dizziness, trepidation and shortness of breath following his first shot of COVID-19 BBIBP-CorV (Sino-pharm). ECG on arrival showed 2:1 atrioventricular block with an underlying old left bundle branch block. The AV block changed into Mobitz type-I over the course of next 2 days and into a sinus 1:1 conduction on fourth day of presentation. However, our patient underwent permanent pacemaker implantation due to the underlying conduction tissue disease and intermittent 2:1 AV block during the hospital stay.

CLINICAL DISCUSSION

It is likely that patients with an already diseased conduction system are at an increased risk of worsening of AV block following inoculation of the vaccine. Vaccine associated AV blocks are likely to be reversible. Presence of prior coronary artery disease and electrical abnormalities are important considerations.

CONCLUSION

COVID-19 vaccine may have added side effects in subjects with known heart disease. Humoral response towards the vaccine might interfere with the conduction system of the heart and more so in patients with diseased and scarred myocardium.

ACR Appropriateness Criteria® Syncope

Syncope and presyncope lead to well over one million emergency room visits in the United States each year. Elucidating the cause of syncope or presyncope, which are grouped together given similar etiologies and outcomes, can be exceedingly difficult given the diverse etiologies. This becomes more challenging as some causes, such as vasovagal syncope, are relatively innocuous while others, such as cardiac-related syncope, carry a significant increased risk of death. While the mainstay of syncope and presyncope assessment is a detailed history and physical examination, imaging can play a role in certain situations. In patients where a cardiovascular etiology is suspected based on the appropriate history, physical examination, and ECG findings, resting transthoracic echocardiography is usually considered appropriate for the initial imaging. While no imaging studies are considered usually appropriate when there is a low probability of cardiac or neurologic pathology, chest radiography may be appropriate in certain clinical situations. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Immune cell diversity contributes to the pathogenesis of myocarditis

Myocarditis (MCD) is a type of inflammatory disease in which inflammatory cells infiltrate the myocardium, leading to cardiac dysfunction, myocardial necrosis, and fibrosis. Although it has been reported that MCD is mediated by T cells, the immune system is complex and includes many types of immune cells that interact with one another. Through investigations of the inflammatory responses in MCD including myocardial necrosis, fibrosis, and arrhythmia, we have gained further insight into the pathogenesis of MCD. This article aims to discuss the diversity and the roles of immune cells involved in the pathogenesis of MCD. Moreover, immunotherapy for the treatment of MCD remains controversial, and further investigation is required to identify accurate immunotherapies for special cell types.

Pathological Features of Complete Atrioventricular Block in Dogs with Lymphocytic Myocarditis

The cardiac conduction system was examined histologically in 12 canine cases of lymphocytic myocarditis with complete atrioventricular (AV) block. Histological analysis showed active myocarditis characterized by intense infiltration of mononuclear cells, primarily lymphoid, associated with degeneration and necrosis of the adjacent cardiomyocytes. Additionally, there was healing or healed myocarditis manifested by disappearance of cardiomyocytes and replacement fibrosis. This destructive inflammatory process of lymphocytic myocarditis involved the whole of the AV conduction system, resulting in loss and deletion of the conduction fibres, as well as the myocardium of all chambers. Such total or subtotal destruction of the AV conduction system caused by the inflammatory changes was thought to have set the stage for blocking AV conduction of cardiac impulses, but the aetiology of the lymphocytic myocarditis was not elucidated.

Indications for permanent pacing in dogs and cats

Pacemaker implantation is considered as a standard procedure for treatment of symptomatic bradycardia in both dogs and cats. Advanced second-degree and third-degree atrioventricular blocks, sick sinus syndrome, persistent atrial standstill, and vasovagal syncope are the most common rhythm disturbances that require pacing to either alleviate clinical signs or prolong survival. Most pacemakers are implanted transvenously, using endocardial leads, but rarely epicardial leads may be necessary. To decide whether a patient is a candidate for pacing, as well as which pacing modality should be used, the clinician must have a clear understanding of the etiology, the pathophysiology, and the natural history of the most common bradyarrhythmias, as well as what result can be achieved by pacing patients with different rhythm disturbances. The goal of this review was, therefore, to describe the indications for pacing by evaluating the available evidence in both human and veterinary medicine. We described the etiology of bradyarrhythmias, clinical signs and electrocardiographic abnormalities, and the choice of pacing modality, taking into account how different choices may have different physiological consequences to selected patients. It is expected that this review will assist veterinarians in recognizing arrhythmias that may require permanent pacing and the risk-benefit of each pacing modality and its impact on outcome.

Third-Degree Atrioventricular Block and Collapse Associated with Eosinophilic Myocarditis in a Horse

Third‐degree atrioventricular block (AVB) and primary inflammatory myocarditis are uncommon findings in horses. The horse of this report presented for collapse at rest and was found to have multiple cardiac arrhythmias, most notably 3rd‐degree AVB. The horse was subsequently diagnosed with eosinophilic myocarditis on necropsy, a rare form of myocarditis not previously reported in horses. Despite extensive testing, an etiologic agent could not be identified, illustrating the difficulty in identifying a specific cause of myocarditis in horses.

Long-term Intrinsic Rhythm Evaluation in Dogs with Atrioventricular Block

Background

Atrioventricular block (AVB) is a conduction abnormality along the atrioventricular node that, depending on etiology, may lead to different outcomes.

Objectives

To evaluate variations of intrinsic rhythm (IR) in dogs that underwent pacemaker implantation (PMI).

Animals

Medical records of 92 dogs affected by 3rd degree atrioventricular block (3AVB), advanced 2nd degree AVB (2AVB), paroxysmal 3AVB, 2:1 2AVB, or 3AVB with atrial fibrillation (AF) were retrospectively reviewed.

Method

The patient IR was documented with telemetry on the day of 1 – (95% CI, 1–2), 33 – (95% CI, 28–35), 105 – (95%CI, 98–156), and 275 days (95%CI, 221–380) after PMI. According to AVB grade at different examinations, AVB was defined as progressed, regressed, or unchanged.

Results

In 48 dogs, 3AVB remained unchanged, whereas in 7 it regressed. Eight cases of 2AVB progressed, 3 regressed and 2 remained unchanged. Eight cases of paroxysmal 3AVB progressed and 3 remained unchanged. Four dogs affected by 2:1 2AVB progressed, 2 regressed, and 1 remained unchanged. All cases with 3AVB with AF remained unchanged. Regression occurred within 30 days after PMI, whereas progression was documented at any time. Variations in IR were associated with type of AVB (P < .03) and time of follow‐up (P < .0001).

Conclusions and clinical importance

The degree of AVB assessed at the time of PMI should not be considered definitive because more than one‐third of the cases in this study either progressed or regressed. Additional studies would be necessary to elucidate possible causes for transient AVB in dogs.

Myocarditis in dogs: etiology, clinical and histopathological features (11 cases: 2007-2013)

Background

Myocarditis is a disease caused by numerous etiological factors and characterized by a non-specific course. The only method allowing for precise characterization of inflammatory changes is the histopathological examination of heart muscle specimens. The study was conducted on heart muscle preparations from 11 dogs with ante-mortem diagnosis of cardiac disease. Animals presented with a poor response to an applied treatment or had suspected sudden cardiac death. The heart specimens were taken post-mortem, preserved and stained with haematoxylin and eosin. Subsequently, the presence and intensity of changes, i.e. inflammatory infiltration, the amount of connective tissue and features of cardiomyocyte degeneration were estimated. The specimens from dogs suspected of having a myocarditis of bacteriological etiology underwent additional bacteriological and immunohistochemical examination.

Results

The examination revealed an inflammatory infiltration of variable intensity combined with the degenerative changes in all dogs. There were vegetative and abnormal cystic forms of Borrelia burgdorferi sensu lato in 6 dogs. A Staphylococcus aureus infection was confirmed in one dog and an acute coronary syndrome with neutrophil infiltration was revealed in another one.

Conclusions

Although the clinical pattern in patients with myocarditis is diverse, the definitive morphological diagnosis is made based on the histopathological examination. This examination can lead to a better understanding of the pathogenesis of the disease. To the best of our knowledge, this is the first description of myocarditis combined with the presence of spore forms of Borrelia burgdorferi sensu lato in the heart specimens of dogs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13620-014-0028-8) contains supplementary material, which is available to authorized users.

In-hospital arrhythmia development and outcomes in pediatric patients with acute myocarditis

Cardiac arrhythmias are a complication of myocarditis. There are no large studies of in-hospital arrhythmia development and outcomes in pediatric patients with acute myocarditis. This was a retrospective 2-center review of patients ≤21 years hospitalized with acute myocarditis from 1996 to 2012. Fulminant myocarditis was defined as the need for inotropic support within 24 hours of presentation. Acute arrhythmias occurred at presentation and subacute after admission. Eighty-five patients (59% men) presented at a median age of 10 years (1 day to 18 years). Arrhythmias occurred in 38 patients (45%): 16 acute, 12 subacute, and 9 acute and subacute (1 onset unknown). Arrhythmias were associated with low voltages on the electrocardiogram (14 of 34, 41% vs 6 of 47, 13%; odds ratio [OR] 4.78, 95% confidence interval [CI] 1.60 to 14.31) and worse outcome (mechanical support, orthotopic heart transplant, or death; OR 7.59, 95% CI 2.61 to 22.07) but were not statistically significantly associated with a fulminant course, ST changes, initial myocardial function, lactate, creatinine level, C-reactive protein and/or erythrocyte sedimentation rate, or troponin I level, after adjusting for multiple comparisons. Subacute arrhythmias were associated with preceding ST changes (10 of 15, 67% vs 15 of 59, 25%, OR 5.87, 95% CI 1.73 to 19.93). All patients surviving to discharge had arrhythmia resolution or control before discharge (10 on antiarrhythmic), with 1 exception (patient with complete heart block requiring a pacemaker). At 1-year follow-up, there were 3 recurrences of ventricular arrhythmias, but no arrhythmia-related mortality. In conclusion, arrhythmias are common in pediatric patients with myocarditis, occurring in nearly 1/2 of all hospitalized children and are associated with a worse outcome. Early identification of subacute arrhythmias using electrocardiographic changes may help management. A majority of patients do not require continued postdischarge arrhythmia treatment.

Corticosteroids for viral myocarditis

BACKGROUND

Myocarditis is defined as inflammation of the myocardium accompanied by myocellular necrosis. Experimental evidence suggests that autoimmune mechanisms follow viral infection, resulting in inflammation and necrosis in the myocardium. However, the use of corticosteroids as immunosuppressives for this condition remains controversial.

OBJECTIVES

The existing review was updated. The primary objective of this review is to assess the beneficial and harmful effects of treating acute or chronic viral myocarditis with corticosteroids. The secondary objective is to determine the best dose regimen.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 7 of 12, 2012) on The Cochrane Library, MEDLINE OVID (1946 to July Week 2, 2012), EMBASE OVID (1980 to Week 29, 2012), BIOSIS Previews (1969 to 20 July 2012), ISI Web of Science (1970 to 20th July, 2012), and LILACS (from its inception to 25 July, 2012) , Chinese Biomed Database, CNKI and WANFANG Databases (from their inception to 31 December 2012). We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of corticosteroids for viral myocarditis compared with no intervention, placebo, supportive therapy, antiviral agents therapy or conventional therapy, including trials of corticosteroids plus other treatment versus other treatment alone, irrespective of blinding, publication status, or language.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data independently. Results were presented as risk ratios (RRs) and mean differences (MDs), both with 95% confidence intervals (CIs).

MAIN RESULTS

Eight RCTs (with 719 participants) were included in this update. The trials were small in size and methodological quality was poor. Viral detection was performed in 38% of participants, among whom 56% had positive results. Mortality between corticosteroids and control groups was non-significant (RR, 0.93, 95% CI 0.70 to 1.24). At 1 to 3 months follow-up, left ventricular ejection fraction (LVEF) was higher in the corticosteroids group compared to the control group (MD 7.36%, 95% CI 4.94 to 9.79), but there was substantial heterogeneity. Benefits were observed in LVEF in two trials with 200 children given corticosteroids (MD 9.00%, 95% CI 7.48 to 10.52). New York Heart Association (NYHA) class and left ventricular end-stage systole diameter (LVESD) were not affected. Creatine phosphokinase (CPK) (MD -104.00 U/L, 95% CI -115.18 to -92.82), Isoenzyme of creatine phosphate MB (CKMB) (MD 10.35 U/L, 95% CI 8.92 to 11.78), were reduced in the corticosteroids group compared to the control group, although the evidence is limited to small participant numbers. There were insufficient data on adverse events.

AUTHORS' CONCLUSIONS

For people diagnosed with viral myocarditis and low LVEF, corticosteroids do not reduce mortality. They may improve cardiac function but the trials were of low quality and small size so this finding must be regarded as uncertain. High-quality, large-scale RCTs should be careful designed to determine the role of corticosteroid treatment for viral myocarditis. Adverse events should also be carefully evaluated.

Myocarditis

Myocarditis is an underdiagnosed cause of acute heart failure, sudden death, and chronic dilated cardiomyopathy. In developed countries, viral infections commonly cause myocarditis; however, in the developing world, rheumatic carditis, Trypanosoma cruzi, and bacterial infections such as diphtheria still contribute to the global burden of the disease. The short-term prognosis of acute myocarditis is usually good, but varies widely by cause. Those patients who initially recover might develop recurrent dilated cardiomyopathy and heart failure, sometimes years later. Because myocarditis presents with non-specific symptoms including chest pain, dyspnoea, and palpitations, it often mimics more common disorders such as coronary artery disease. In some patients, cardiac MRI and endomyocardial biopsy can help identify myocarditis, predict risk of cardiovascular events, and guide treatment. Finding effective therapies has been challenging because the pathogenesis of chronic dilated cardiomyopathy after viral myocarditis is complex and determined by host and viral genetics as well as environmental factors. Findings from recent clinical trials suggest that some patients with chronic inflammatory cardiomyopathy have a progressive clinical course despite standard medical care and might improve with a short course of immunosuppression.

Preoperative total lymphocyte count in peripheral blood as a predictor of poor outcome in adult cardiac surgery

OBJECTIVE

The aim of this study was to investigate the prognostic value of the preoperative total lymphocyte count in peripheral blood as a predictor of postoperative complications and mortality in cardiac surgery.

DESIGN

A retrospective, observational study.

SETTING

The Novosibirsk State Research Institute of Circulation Pathology (single institution).

PARTICIPANTS

All adults undergoing primary cardiopulmonary bypass in 2009.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The cohort size was 1,368 patients operated upon with cardiopulmonary bypass. Patient characteristics, hospital mortality, postoperative complications, ventilation time, intensive care unit, and hospital stay were analyzed. A preoperative total lymphocyte count <1,500 cells/μL was associated with significantly higher mortality by univariate (p < 0.0001) and multivariate (p < 0.044) analyses. A low preoperative total lymphocyte count was associated with more frequent inotropic support (p < 0.001); postoperative heart arrhythmia (p < 0.001); dialysis-dependent acute renal failure (p < 0.001); and a prolonged ventilation time (p = 0.001), intensive care unit stay (p < 0.001), and hospital stay (p = 0.007).

CONCLUSIONS

A low preoperative total lymphocyte count in peripheral blood is a useful prognostic criterion for the evaluation of a complicated postoperative period in cardiac patients operated under cardiopulmonary bypass.

Cardiac troponin-I concentrations in dogs with bradyarrhythmias before and after artificial pacing

OBJECTIVES

To quantify cardiac troponin-I (cTnI) concentration in dogs with symptomatic bradyarrhythmias before and after artificial pacing and to correlate cTnI concentration with diagnosis, echocardiographic parameters, serology, and outcome.

ANIMALS, MATERIALS AND METHODS

Medical records from the University of Pennsylvania from 2006 to 2009 were reviewed, and 14 dogs with cTnI assay results before and after pacemaker were identified. The ECG diagnosis included complete atrioventricular block (AVB), sick sinus syndrome, 2nd degree AVB, and atrial standstill. Serology, presence of premature beats, echocardiographic measurements, and pacing modality were recorded.

RESULTS

Mean cTnI concentration was elevated both pre- and post-pacing, and was significantly higher pre-pacing vs. post-pacing. Post-pacing cTnI concentration in 9 of 14 dogs (64%) remained above the reference range. Four dogs yielded high serum titers for Bartonella spp. Four dogs with markedly increased cTnI concentration had progressive left ventricular enlargement and myocardial failure as compared to pre-pacing examination.

CONCLUSIONS

Elevated cTnI concentration suggests that cardiac injury persists after artificial pacing in dogs with bradyarrhythmias. Myocarditis secondary to Bartonella spp. or other causes may be an important cause of AVB in dogs. Prospective studies investigating the correlation of cTnI to potential etiology and development of post-pacing LV dysfunction and outcome are needed.

Effect of transplantation of bone marrow cells on morphology of rat myocardium after cryodestruction

We studied the effects of bone marrow cell transplantation on myocardium of the prenecrotic zone in Wistar rats. Intramyocardial cell transplantation reduced the severity of hypertrophy of myocardium and the degree of its cicatricial degeneration on day 40 after cryodestruction. The morphology of the myocardium in the prenecrotic zone depended on the type of transplanted cells. The course of inflammation was swifter; vascularization of the myocardium was more intensive. The best effect, evaluated by the number of new vessels, was observed after MSC transplantation. Hence, the positive effect of bone marrow cell transplantation is realized at the expense of more rapid structural organization of the damaged site and stimulation of myocardial vascularization.

Complete atrioventricular block in an adolescent with rheumatic Fever

Rheumatic fever is an acute inflammatory sequela following a group A, β-hemolytic streptococcal infection. Rheumatic fever is characterized by polyarthritis, carditis, chorea, subcutaneous nodules, and erythema marginatum as the major diagnostic criteria. Rarely, advanced heart block may also occur. A 13-year-old boy was admitted to the Pediatric Department for evaluation and management of complete atrioventricular block. The patient had exertional dyspnea for 1 month. Based on the findings of mitral regurgitation, fever, elevated acute phase reactants, and a high antistreptolysin O titer, the patient was diagnosed with rheumatic fever. A benzathine penicillin injection was administered, as well as salicylate therapy. On the 5^th day of hospitalization, the electrocardiogram revealed a normal sinus rhythm with a 1^st degree atrioventricular block. After discharge, the electrocardiogram normalized with the monthly penicillin injections. Herein we report a case of complete atrioventricular block associated with rheumatic fever. The heart block resolved without specific cardiac treatment, other than a non-steroidal anti-inflammatory medication.

Increased myocardial collagen turnover in patients with progressive cardiac conduction disease

BACKGROUND

Histopathologically, progressive cardiac conduction disease (PCCD) is characterized by progressive fibrosis and sclerodegenerative changes in the proximal and distal conduction system of the heart. Therefore, we sought to determine the serum levels of myocardial collagen turnover markers, extracellular matrix components, transforming growth factor beta(1) (TGFbeta(1)), and bone morphogenic protein-7 (BMP-7) in this population.

METHODS

Study population included 20 patients (6 M/14 F, mean age 76 +/- 8 years) with acquired, permanent 2:1, or complete atrioventricular block and compared with age- and sex-matched, asymptomatic, healthy control subjects (n = 18, 6 M/12 F, mean age 75 +/- 7 years). Serum myocardial collagen turnover markers:matrix metalloproteinases (MMP-1, 2, 9), tissue inhibitor of matrix metalloproteinase (TIMP-1), amino-terminal propeptide of procollagen type I (PINP) and type III (PIIINP), carboxy-terminal telopeptide of collagen type I (CITP), and carboxy-terminal propeptide of procollagen type I (PICP), serum extracellular matrix components (laminin and fibronectin), TGFbeta(1), and BMP-7 levels were measured in both groups.

RESULTS

Serum PICP (849 +/- 396 vs 631 +/- 294 ng/mL, P = 0.04), PIIINP (3.7 +/- 1.3 vs 3 +/- 1 mug/L, P = 0.03), CITP (0.68 +/- 0.35 vs 0.48 +/- 0.25 ng/mL, P = 0.037), and plasma MMP-9 (58.8 +/- 56 vs 25.9 +/- 17.3 ng/mL, P = 0.006) levels were higher in patient population compared to control subjects. Serum MMP-1 (24.1 +/- 20.5 vs 13.6 +/- 7.5 ng/mL, P = 0.045) and MMP-2 (1310 +/- 139 vs 1186 +/- 163 ng/mL, P = 0.01) levels were higher in control subjects compared to patient population. There was no difference in serum TIMP-1, PINP, laminin, fibronectin, TGFbeta(1), and BMP-7 levels between two groups.

CONCLUSION

Our findings demonstrate the presence of increased myocardial collagen turnover and active fibrotic process in patients with PCCD compared to control subjects.