Lyme carditis--diagnosis, treatment and prognosis

A Rare Presentation of Lyme Disease in an Immunocompromised Patient

Lyme disease is a progressive infectious disease caused by the Borrelia species that affects multiple organ systems, including the brain, heart, skin, and musculoskeletal systems. The cardiac manifestations of Lyme disease typically present with atrioventricular nodal conduction abnormalities and, more rarely, myocarditis. We report a case of an immunocompromised 57-year-old woman who presented with acute onset shortness of breath, hypervolemia, injective conjunctiva, and global vision loss of the left eye in the setting of a recent tick bite. Serologic testing confirmed borreliosis, and cardiac testing demonstrated acute isolated systolic heart failure without any cardiac conduction system abnormalities on the electrocardiogram. The diagnosis of Lyme carditis was made, and the patient was started on doxycycline with complete recovery of cardiac systolic function. This case demonstrates atypical cardiac manifestations of Lyme disease and highlights the difficulty in workup and understanding of Lyme carditis particularly in immunocompromised patients.

Tick-Borne Myopericarditis With Positive Anaplasma, Lyme, and Epstein Barr Virus (EBV) Serology: A Case Report

Myopericarditis has been reported only rarely in those with anaplasmosis and is typically difficult to diagnose. Lyme carditis can also be difficult to diagnose as it is relatively rare but potentially fatal and usually has nonspecific manifestations. We are presenting a 61-year-old male patient who presented in New Jersey, United States with unremitting fever, chills, and myalgia for two weeks along with nausea, vomiting, and diarrhea. Investigations were suggestive of perimyocarditis as was indicated by diffuse ST segment elevation on electrocardiography (EKG) with the presence of small pericardial effusion on echocardiography. A mild troponin leakage was also seen. This progressed to septic shock that required vasopressor therapy. Further history-taking revealed recent tick exposure and prompted empirical initiation of doxycycline. This proved to be successful with fever defervescence and clinical improvement. Serological tests confirmed both acute Lyme and anaplasma infections along with positive serology of Epstein Barr virus (EBV). This case highlights an uncommon presentation of carditis in acute Lyme and anaplasma infections with the associated false-positive serology of EBV.

An Atypical Case of Lyme Disease Presenting With Lyme Carditis

Lyme carditis is a rare but serious manifestation of Lyme disease presenting in the early disseminated stage of the disease often after a diagnosis has already been discovered. The classic case of Lyme disease presents a patient who had been participating in outdoor activities in a Lyme-endemic region and was found to have a tick bite. These patients often present in the early localized stage, within the first 1-2 weeks with the well-recognized erythema-migrans rash or with generalized flu-like symptoms. Here we describe a case of a 70-year-old male who presented to the hospital without any typical Lyme disease prodrome but instead with generalized symptoms of progressive orthopnea and dyspnea on exertion. His original diagnoses were not of infectious origin however after incidentally being found to have a second degree, Mobitz type 1 atrioventricular (AV) block; Lyme tests were ordered, and a diagnosis was confirmed. This incidence shows the importance of having a Lyme disease diagnosis when regionally appropriate for patients who may present with no other signs or symptoms other than an AV block. As in this case, after a diagnosis has been made the management becomes the treatment of the infection rather than the treatment of the symptoms themselves.

Serologic Status of Borrelia burgdorferi sensu lato in Patients with Cardiovascular Changes

Cardiovascular diseases, particularly coronary heart disease (CHD) caused by atherosclerosis, have the highest worldwide incidence and mortality rate of any type of disease. Aside from risk factors associated with lifestyle and comorbidities, infectious agents such as Borrelia burgdorferi sensu lato spirochetes, which cause Lyme disease, may also play a role in the development of cardiovascular disease. A growing number of scientific papers have mentioned Lyme carditis. The aim of this study was to find the level of anti-Borrelia IgG antibodies in the blood serum of patients with advanced coronary heart disease. Materials and methods: The study group included 70 patients undergoing coronary artery bypass grafting (CABG) and off-pump coronary artery bypass (OPCAB) surgery aged 50 to 82 (average 68.26). The ELISA test was used to detect anti-Borrelia/IgG antibodies in the blood serum. Serological testing revealed seropositivity in 34.29% of patients and 'borderline results' in 17.14% of patients. We found a link between antibody levels and tick bites but not with other risk factors for the development of CHD. Conclusions: These findings support the idea that, as one of many factors, the contact with spirochetal antigens may indicate a potential positive correlation with the formation of cardiovascular changes. More research, not only at the diagnostic level but also at the advanced research level, is needed.

Prevalence of Lyme Carditis in Patients with Atrioventricular Blocks

Infections with Borrelia may cause cardiac conduction system abnormalities, including atrioventricular blocks (AVBs). Therefore, we aimed to identify patients in whom Lyme carditis (LC) could be considered as the initial diagnosis among consecutive subjects who were referred for implantation of a permanent pacemaker due to symptomatic AVBs. To date, such a systematic evaluation has not been reported yet. Validation of the Suspicious Index for Lyme Carditis (SILC) in our study population was considered as an additional goal. We investigated consecutive patients with AVB admitted to our department for a pacemaker implantation. Serological diagnostic tests against Borrelia burgdorferi sensu lato (Bbsl) were performed in those with no obvious cardiac causes of AVB. The final study population consisted of 130 patients (80 M, mean age 67.4 ± 17.6). Lyme carditis was assumed as the initial diagnosis in 16 patients (12%) based on ABV and IgM Bbsl seropositivity. The patients with LC were younger and more frequently manifested constitutional symptoms of infection and fluctuating AVB. The highest prognostic value for identification of LC patients was obtained for the modified SILC, which included the following parameters: (1) age lower than 75 years; (2) risky outdoor activity and living in the countryside; (3) tick bite; (4) constitutional symptoms of Lyme disease; (5) erythema migrans; (6) male sex and (7) fluctuating atrioventricular block. We concluded that diagnostics for LC should be routinely considered in patients with advanced AVB. Modified SILC may identify the patients at risk of LC.

Infection with Borrelia burgdorferi Increases the Replication and Dissemination of Coinfecting Powassan Virus in Ixodes scapularis Ticks

Powassan virus (POWV) is a tick-borne neuroinvasive flavivirus endemic to North America. It is generally transmitted by the tick, Ixodes scapularis. This species also transmits Borrelia burgdorferi, the causative agent of Lyme disease. Infection with B. burgdorferi can result in arthritis, carditis, and neuroborreliosis. These pathogens experience sylvatic overlap. To determine the risk of human exposure to coinfected ticks, the interactions between POWV and B. burgdorferi are assessed in laboratory-infected I. scapularis. Adult male and female I. scapularis ticks are orally inoculated with either both pathogens, POWV only, B. burgdorferi only, or uninfected media. After twenty-one days, the ticks are dissected, and RNA is extracted from their midguts and salivary glands. In infected midguts, the quantity of POWV in coinfected ticks was elevated compared to those with only POWV. In addition, the salivary glands of ticks with infected midguts had increased POWV dissemination to those with only POWV. RNA sequencing is performed to identify the potential mechanism for this pattern, which varies between the organs. Ixodes scapularis ticks are found to be capable of harboring both POWV and B. burgdorferi with a benefit to POWV replication and dissemination.

Lyme Carditis: From Pathophysiology to Clinical Management

Cardiac involvement is a rare but relevant manifestation of Lyme disease that frequently presents as atrioventricular block (AVB). Immune-mediated injury has been implicated in the pathogenesis of Lyme carditis due to possible cross-reaction between Borrelia burgdorferi antigens and cardiac epitopes. The degree of the AVB can fluctuate rapidly, with two-thirds of patients progressing to complete AVB. Thus, continuous heart rhythm monitoring is essential, and a temporary pacemaker may be necessary. Routinely permanent pacemaker implantation, however, is contraindicated because of the frequent transient nature of the condition. Antibiotic therapy should be initiated as soon as the clinical suspicion of Lyme carditis arises to reduce the duration of the disease and minimize the risk of complications. Diagnosis is challenging and is based on geographical epidemiology, clinical history, signs and symptoms, serological testing, ECG and echocardiographic findings, and exclusion of other pathologies. This paper aims to explain the pathophysiological basis of Lyme carditis, describe its clinical features, and delineate the treatment principles.

Incidence of carditis and predictors of pacemaker implantation in patients hospitalized with Lyme disease

BACKGROUND

Lyme carditis, defined as direct infection of cardiac tissue by Borrelia bacteria, affects up to 10% of patients with Lyme disease. The most frequently reported clinical manifestation of Lyme carditis is cardiac conduction system disease. The goal of this study was to identify the incidence and predictors of permanent pacemaker implantation in patients hospitalized with Lyme disease.

METHODS

A retrospective cohort analysis of the Nationwide Inpatient sample was performed to identify patients hospitalized with Lyme disease in the US between 2003 and 2014. Patients with Lyme carditis were defined as those hospitalized with Lyme disease who also had cardiac conduction disease, acute myocarditis, or acute pericarditis. Patients who already had pacemaker implants at the time of hospitalization (N = 310) were excluded from the Lyme carditis subgroup. The primary study outcome was permanent pacemaker implantation. Secondary outcomes included temporary cardiac pacing, permanent pacemaker implant, and in-hospital mortality.

RESULTS

Of the 96,140 patients hospitalized with Lyme disease during the study period, 10,465 (11%) presented with Lyme carditis. Cardiac conduction system disease was present in 9,729 (93%) of patients with Lyme carditis. Permanent pacemaker implantation was performed in 1,033 patients (1% of all Lyme hospitalizations and 11% of patients with Lyme carditis-associated conduction system disease). Predictors of permanent pacemaker implantation included older age (OR: 1.06 per 1 year; 95% CI:1.05-1.07; P<0.001), complete heart block (OR: 21.5; 95% CI: 12.9-35.7; P<0.001), and sinoatrial node dysfunction (OR: 16.8; 95% CI: 8.7-32.6; P<0.001). In-hospital mortality rate was higher in patients with Lyme carditis (1.5%) than in patients without Lyme carditis (0.5%).

CONCLUSIONS

Approximately 11% of patients hospitalized with Lyme disease present with carditis, primarily in the form of cardiac conduction system disease. In this 12-year study, 1% of all hospitalized patients and 11% of those with Lyme-associated cardiac conduction system disease underwent permanent pacemaker implantation.

Early Onset Lyme Myopericarditis With Left Ventricular Dysfunction and Mitral Regurgitation

Lyme carditis is a rare manifestation of early disseminated Lyme disease with an incidence of 0.5% with left ventricular dysfunction and valvular involvement being exceedingly rare. Clinical manifestations typically occur 1 to 2 months after infection and include arrhythmias, conduction abnormalities, myopericarditis, and ventricular dysfunction. If left untreated, Lyme carditis can lead to acute heart failure and sudden cardiac death thus prompt diagnosis and treatment are essential in management. Here, we present a case of Lyme carditis with left ventricular dysfunction and valvular involvement occurring shortly after known tick exposure.

[Dyspnea and palpitations in a 39-year-old male patient]

A 39-year-old male patient presented with dyspnea and palpitations. The electrocardiogram (ECG) showed a first degree atrioventricular (AV) block and frequent atrial extra systoles. Within the following 48 h the AV block gradually developed into a third degree intermittent complete AV block. The patient history included an untreated tick bite 2 months before presentation. The serological proof of antibodies confirmed the diagnosis of Lyme carditis and antibiotic treatment with ceftriaxon i.v. was initiated. Normal AV conduction finally resumed and the symptoms subsided completely without any further clinical consequences.

Lyme Carditis: A Reversible Cause of Acquired Third-Degree AV Block

Patient: Male, 36-year-old

Final Diagnosis: Lyme carditis

Symptoms: Fatigue • myalgia

Medication: —

Clinical Procedure: Transcutaneous pacemaker

Specialty: Cardiology

Lyme Disease in Humans

Lyme disease (Lyme borreliosis) is a tick-borne, zoonosis of adults and children caused by genospecies of the Borrelia burgdorferi sensu lato complex. The ailment, widespread throughout the Northern Hemisphere, continues to increase globally due to multiple environmental factors, coupled with increased incursion of humans into habitats that harbor the spirochete. B. burgdorferi sensu lato is transmitted by ticks from the Ixodes ricinus complex. In North America, B. burgdorferi causes nearly all infections; in Europe, B. afzelii and B. garinii are most associated with human disease. The spirochete's unusual fragmented genome encodes a plethora of differentially expressed outer surface lipoproteins that play a seminal role in the bacterium's ability to sustain itself within its enzootic cycle and cause disease when transmitted to its incidental human host. Tissue damage and symptomatology (i.e., clinical manifestations) result from the inflammatory response elicited by the bacterium and its constituents. The deposition of spirochetes into human dermal tissue generates a local inflammatory response that manifests as erythema migrans (EM), the hallmark skin lesion. If treated appropriately and early, the prognosis is excellent. However, in untreated patients, the disease may present with a wide range of clinical manifestations, most commonly involving the central nervous system, joints, or heart. A small percentage (~10%) of patients may go on to develop a poorly defined fibromyalgia-like illness, post-treatment Lyme disease (PTLD) unresponsive to prolonged antimicrobial therapy. Below we integrate current knowledge regarding the ecologic, epidemiologic, microbiologic, and immunologic facets of Lyme disease into a conceptual framework that sheds light on the disorder that healthcare providers encounter.

A Practical Approach to the Diagnosis of Lyme Borreliosis: From Clinical Heterogeneity to Laboratory Methods

Clinical evaluation of Lyme Borreliosis (LB) is the starting point for its diagnosis. The patient's medical history and clinical symptoms are fundamental for disease recognition. The heterogeneity in clinical manifestations of LB can be related to different causes, including the different strains of Borrelia, possible co-infection with other tick transmitted pathogens, and its interactions with the human host. This review aims at describing the heterogeneous symptoms of Lyme Borreliosis, as well as offering a practical approach for recognition of the disease, both in terms of clinical features and diagnostic/research tools.

Early Disseminated Lyme Carditis Inducing High-Degree Atrioventricular Block

Lyme disease is the most common tick-borne illness in the United States due to Borrelia burgdorferi infection. This case demonstrates a 20-year-old male patient presenting with complaints of annular skin rash, malaise, fever, and lightheadedness after significant outdoor exposure. Physical exam revealed multiple large targetoid lesions on the back and extremities. The rash had raised borders and centralized clearing consistent with erythema migrans chronicum. Electrocardiogram (ECG) revealed a high-degree atrioventricular (AV) block. The patient was started on intravenous ceftriaxone due to clinical suspicion for Lyme carditis. ELISA and Western blot tests were reactive for Lyme IgM and IgG, confirming the diagnosis. The AV block resolved by hospital day four and the patient was discharged with outpatient follow-up. Early identification of disease allowed for effective treatment with no adverse outcomes or sequelae.

First report of Lyme borreliosis leading to cardiac bradydysrhythmia in two cats

Case series summary

Two cats were presented for investigation of bradyarrhythmia detected by their referring veterinarians during routine examination. Both cats had extensive investigations, including haematology, serum biochemistry with electrolytes and thyroxine concentrations, systolic blood pressure measurement, echocardiography, electrocardiography and infectious disease testing. Infectious disease testing included serology for Toxoplasma gondii, Ehrlichia canis, Anaplasma phagocytophilum and Borrelia burgdorferi, and PCR for B burgdorferi antigen in both cats. Case 1 was also assessed by PCR for Bartonella henselae antigen and case 2 was assessed for Dirofilaria immitis by serology. All infectious disease tests, other than for B burgdorferi, were negative. Case 1 was diagnosed with Lyme carditis based on marked bradydysrhythmia, positive B burgdorferi serology, a structurally normal heart and clinical resolution with appropriate treatment with a 4-year follow-up. Case 2 was diagnosed with Lyme carditis based on marked bradydysrhythmia and positive B burgdorferi PCR; however, this cat had structural heart disease that did not resolve with treatment.

Relevance and novel information

This small case series describes two B burgdorferi positive cats presenting with newly diagnosed cardiac abnormalities consistent with those found in humans and dogs with Lyme carditis. Both cats were asymptomatic as perceived by their owners; the arrhythmia was detected by their veterinarians.

Diagnostic and prognostic role of electrocardiogram in acute myocarditis: A comprehensive review

Background

Acute myocarditis represents a challenging diagnosis as there is no pathognomonic clinical presentation. In patients with myocarditis, electrocardiogram (ECG) can display a variety of non‐specific abnormalities. Nevertheless, ECG is widely used as an initial screening tool for myocarditis.

Methods

We researched all possible ECG alterations during acute myocarditis evaluating prevalence, physiopathology, correlation with clinical presentation patterns, role in differential diagnosis, and prognostic yield.

Results

The most common ECG abnormality in myocarditis is sinus tachycardia associated with nonspecific ST/T‐wave changes. The presence of PR segment depression both in precordial and limb leads, a PR segment depression in leads with ST segment elevation, a PR segment elevation in aVR lead or a ST elevation with pericarditis pattern favor generally diagnosis of perimyocarditis rather than myocardial infarction. In patients with acute myocarditis, features associated with a poorer prognosis are: pathological Q wave, wide QRS complex, QRS/T angle ≥ 100°, prolonged QT interval, high‐degree atrioventricular block and malignant ventricular tachyarrhythmia. On the contrary, ST elevation with a typical early repolarization pattern is associated with a better prognosis.

Conclusions

ECG alterations in acute myocarditis could be very useful in clinical practice for a patient‐tailored approach in order to decide appropriate therapy, length of hospitalization, and frequency of followup.

Lyme Carditis: A Rare Presentation of Sinus Bradycardia Without Any Conduction Defects

Lyme carditis is a rare cardiac manifestation of Lyme disease that occurs when bacterial spirochetes infect the pericardium or myocardium triggering an inflammatory response. The most common electrocardiogram (EKG) findings in these patients include atrioventricular (AV) conduction abnormalities (first, second, and third degree heart block). A 56-year-old male with a history of hypothyroidism, from the Northeastern region of the United States, presented to the emergency department with lightheadedness and chest pain. His EKG revealed sinus bradycardia with a heart rate of 49 beats per minute, without ST segment elevation, T wave inversions, or signs of heart block. An enzyme-linked immunosorbent assay (ELISA) Lyme titer was elevated, and confirmatory Western blot was positive for IgG and negative for IgM. He was treated with intravenous (IV) ceftriaxone; however, he continued to have persistent bradycardia with his heart rate dropping to 20 to 30 beats per minute throughout the night. Additionally, he had several sinus pauses while sleeping, with the longest lasting for 6.1 seconds. A pacemaker and an additional three-week course of IV ceftriaxone was determined to be the best treatment for his resistant bradycardia secondary to Lyme carditis. No symptoms were present at his one month follow-up appointment, as an outpatient, after completing ceftriaxone therapy. The patient follows up with cardiology regularly to have his pacemaker checked. Here we present a unique case of Lyme carditis, without the classical findings of Lyme disease or common EKG findings of AV conduction abnormalities. A high clinical suspicion of Lyme carditis is required when someone from a Lyme endemic region presents with unexplained cardiac symptoms and electrocardiogram abnormalities. This case report aims to add to the knowledge gap between suspicion of Lyme carditis and sinus bradycardia as the only presenting symptom.

Borrelia and Chlamydia Can Form Mixed Biofilms in Infected Human Skin Tissues

Our research group has recently shown that Borrelia burgdorferi, the Lyme disease bacterium, is capable of forming biofilms in Borrelia-infected human skin lesions called Borrelia lymphocytoma (BL). Biofilm structures often contain multiple organisms in a symbiotic relationship, with the goal of providing shelter from environmental stressors such as antimicrobial agents. Because multiple co-infections are common in Lyme disease, the main questions of this study were whether BL tissues contained other pathogenic species and/or whether there is any co-existence with Borrelia biofilms. Recent reports suggested Chlamydia-like organisms in ticks and Borrelia-infected human skin tissues; therefore, Chlamydia-specific polymerase chain reaction (PCR) analyses were performed in Borrelia-positive BL tissues. Analyses of the sequence of the positive PCR bands revealed that Chlamydia spp. DNAs are indeed present in these tissues, and their sequences have the best identity match to Chlamydophila pneumoniae and Chlamydia trachomatis. Fluorescent immunohistochemical and in situ hybridization methods demonstrated the presence of Chlamydia antigen and DNA in 84% of Borrelia biofilms. Confocal microscopy revealed that Chlamydia locates in the center of Borrelia biofilms, and together, they form a well-organized mixed pathogenic structure. In summary, our study is the first to show Borrelia-Chlamydia mixed biofilms in infected human skin tissues, which raises the questions of whether these human pathogens have developed a symbiotic relationship for their mutual survival.

First case report of inducible heart block in Lyme disease and an update of Lyme carditis

Background

Lyme disease (LD), is the most common vector-borne illness in the US and Europe, with predominantly cutaneous, articular, cardiac and neuro-psychiatric manifestations. LD affects all layers of the heart and every part of the conducting system. Carditis is a less common manifestation of LD. Heart block (HB) as the initial and sole manifestation of LD is rare. Inducible HB has never been reported in LD. We report a case of heart block (HB) inducible with exercise and reversible with rest.

Case presentation

A 37-year-old male presented to the emergency department after experiencing two episodes of syncope while at work. He presented, with a heart rate of 57 bpm, and the ECG showed sinus bradycardia with first degree AV block. The PR interval was 480 ms (NL 120–200 ms). Physical exam was unremarkable. The cardiologist’s initial impression was vaso-vagal attack. He developed high degree AV block during a stress test for the initial work up, which resolved on cessation of exercise. A similar episode while walking in the hallway, resolved at rest. The high degree AV block appeared inducible with exercise and reversible with rest. His Lyme serology was strongly positive. He was treated with ceftriaxone and doxycycline. After completing treatment, the patient had a normal ECG and returned to work without limitations, doing manual labor.

Conclusions

Manifestations of Lyme carditis (LC) vary from asymptomatic and symptomatic electrocardiographic changes and heart block (HB) reversible with treatment, to sudden death. HB as the sole and initial presentation of LC is rare. There have been no reports of inducible HB in LD. Here we present a case of inducible and reversible high degree HB in a case of LC and an update of literature. Exercise and stress testing should be avoided in suspected cases of LC until resolution of carditis. Lyme carditis should be suspected in individuals with cardiac manifestations in an endemic area, particularly in the younger patients with no other etiology evident.

Lyme Disease-An Unusual Cause of a Mitral Valve Endocarditis

Lyme disease is a tick-borne infection caused by Borrelia burgdorferi. Cardiac manifestations are rare, occurring in 0.5% to 10% of patients. Lyme carditis and atrioventricular block are established manifestations of Lyme disease. Endocarditis caused by Borrelia has been reported only twice previously, and in both cases, these were species (Borrelia afzelii and Borrelia bissettii) not present in North America. We report a unique case of mitral valve endocarditis caused by B burgdorferi.

Clinical spectrum of Lyme disease

Lyme disease (borreliosis) is one of the most common vector-borne diseases worldwide. Its incidence and geographic expansion has been steadily increasing in the last decades. Lyme disease is caused by Borrelia burgdorferi sensu lato, a heterogeneous group of which three genospecies have been systematically associated to Lyme disease: B. burgdorferi sensu stricto Borrelia afzelii and Borrelia garinii. Geographical distribution and clinical manifestations vary according to the species involved. Lyme disease clinical manifestations may be divided into three stages. Early localized stage is characterized by erythema migrans in the tick bite site. Early disseminated stage may present multiple erythema migrans lesions, borrelial lymphocytoma, lyme neuroborreliosis, carditis, or arthritis. The late disseminated stage manifests with acordermatitis chronica atrophicans, lyme arthritis, and neurological symptoms. Diagnosis is challenging due to the varied clinical manifestations it may present and usually involves a two-step serological approach. In the current review, we present a thorough revision of the clinical manifestations Lyme disease may present. Additionally, history, microbiology, diagnosis, post-treatment Lyme disease syndrome, treatment, and prognosis are discussed.

Treating Lyme carditis high-degree AV block using a temporary-permanent pacemaker

A 28-year-old previously healthy male presented with nonprodromal syncope and a 4-day history of chest pain, shortness of breath, and malaise. His ECG showed rapidly progressive high-degree AV block. His Suspicious Index in Lyme Carditis (SILC) score was 8, indicating high risk for Lyme carditis. Lyme serology revealed to be positive (anti-Lyme IgM). During the second day of hospitalization, the patient deteriorated his AV conduction, and a temporary-permanent pacemaker was implanted allowing ambulating in hospital the very same day. Temporary-permanent pacemakers for the management of transient high-degree heart block associated with Lyme carditis were only occasionally used in the past.

A Case of Lyme Carditis Presenting with Atrial Fibrillation

We report a case of a 20-year-old man who presented to our institution with a new arrhythmia on a routine EKG. Serial EKG tracings revealed various abnormal rhythms such as episodes of atrial fibrillation, profound first degree AV block, and type I second degree AV block. He was found to have positive serologies for Borrelia burgdorferi. After initiation of antibiotic therapy, the atrial arrhythmias and AV block resolved. Here, we present a case of Lyme carditis presenting with atrial fibrillation, a highly unusual presentation of Lyme carditis.

[Follow-up of patients with Ixodes tick-borne borrelioses caused by Borrelia miyamotoi or Borrelia burgdorferi sensu lato]

Ixodes tick-borne borrelioses (ITBB) are caused by two different spirochetes: Borrelia from the group of Borrelia burgdorferi sensu lato, the agents of the classic Lyme borreliosis (LB), and Borrelia miyamotoi that belongs to the group of Borrelia causing tick-borne relapsing fevers. ITBB caused by B. miyamotoi (BM-ITBB) is a previously unknown infectious disease discovered in Russia. It is known that the LB sequelae may reduce the long-term life guality of convalescents.

AIM

To study the follow-up of those who have recovered from new BM-ITBB infection in comparison with persons who have had LB.

SUBJECTS AND METHODS

The investigation enrolled 41 patients with BM-ITBB and 41 patients with LB who were treated at the Republican Infectious Diseases Hospital of Udmurtia. Within a year after the disease, they were followed up through clinical and instrumental examination of cardiac performance, expanded biochemical analysis of blood and urine, which could; estimate kidney and liver functions, and psychological questioning.

RESULTS

Asthenic syndrome and complaints about and objective signs of cardiac dysfunctions persisted supraventricular extrasystoles, left ventricular diastolic dysfunction, and elevated and/or unstable systolic blood pressure were detected in 20-30% of the convalescents for a long time. Kidney dysfunctions were manifested in albuminuria and the decrease of glomerular filtration rate. A year following the disease, 10-20% patients had persistently elevated concentrations of alanine aminotransferase, aspartate aminotransferase, and C-reactive protein and had higher levels of total cholesterol and low-density lipoproteins. The pathological consequences of ITBB were polymorphic and varied in different patients; in general, only 68% of them showed health improvement.

CONCLUSION

We assume that a significant role in the pathogenesis of BM-ITBB and LB is played by vascular endothelial damage possibly associated with the inflammatory and autoimmune aspects of an immune response in Borrelia infection. The consequences of this damage may persist and even intensify during a year, which provokes chronic dysfunction of the heart, kidney, or liver in a number of convalescents.

Role of Non-Myocyte Gap Junctions and Connexin Hemichannels in Cardiovascular Health and Disease: Novel Therapeutic Targets?

The heart is a complex organ composed of multiple cell types, including cardiomyocytes and different non-myocyte populations, all working closely together to determine the hearts properties and maintain normal cardiac function. Connexins are abundantly expressed proteins that form plasma membrane hemichannels and gap junctions between cells. Gap junctions are intracellular channels that allow for communication between cells, and in the heart they play a crucial role in cardiac conduction by coupling adjacent cardiomyocytes. Connexins are expressed in both cardiomyocytes and non-myocytes, including cardiac fibroblasts, endothelial cells, and macrophages. Non-myocytes are the largest population of cells in the heart, and therefore it is important to consider what roles connexins, hemichannels, and gap junctions play in these cell types. The aim of this review is to provide insight into connexin-based signalling in non-myocytes during health and disease, and highlight how targeting these proteins could lead to the development of novel therapies. We conclude that connexins in non-myocytes contribute to arrhythmias and adverse ventricular remodelling following myocardial infarction, and are associated with the initiation and development of atherosclerosis. Therefore, therapeutic interventions targeting these connexins represent an exciting new research avenue with great potential.

Lyme Carditis: A Case Report and Review of Management

Purpose: A case report of a patient who presented with an acute onset, fluctuating atrioventricular (AV) block and was diagnosed with Lyme carditis is presented. Summary: A 55-year-old man with progressively worsening generalized malaise, flu-like symptoms, dyspnea on exertion, and near syncope was admitted with bradycardia (heart rate was between 20 and 30 beats per minute upon admission). He endorsed having several tick bites after which he developed erythema migrans on his arm and abdomen. An electrocardiogram (ECG) revealed a second-degree AV block, fluctuating between Mobitz type I and Mobitz type II heart block, with a P-R interval of 300 ms. A presumptive diagnosis of Lyme carditis was made based on a confirmed history of tick exposure, presence of erythema migrans, and AV block. The patient was started on ceftriaxone. On day 3 of hospitalization, patient's heart rate was between 50 and 60 beats per minute. A diagnosis of Lyme disease was confirmed based on serologic testing. A repeat ECG revealed a first-degree AV block with a P-R interval of 300 ms. On day 5 of hospitalization, a peripherally inserted central catheter line was placed and the patient was discharged to his home on a 28-day course of ceftriaxone. Patient's heart rate was 65 beats per minute on discharge day. Conclusion: Considering Lyme carditis as a differential diagnosis in patients with an AV block of an unknown etiology can result in a timely diagnosis and treatment of Lyme carditis.

Successful treatment of fulminant Lyme myocarditis with mechanical circulatory support in a young male adult: a case report

We describe the case of fulminant myocarditis due to Lyme disease and use of mechanical circulatory support (MCS) for the treatment of the Lyme carditis associated with refractory cardiogenic shock. Fulminant Lyme myocarditis in young adult male patient led to a sudden onset of acute, severe biventricular heart failure with progressive cardiogenic shock, and multiorgan failure immediately after admission.

The previously healthy 28-year-old man was admitted to hospital with dyspnea, atrial flutter with 160/min ventricles rate, normotension, cardiomegaly, and incipient cardiogenic pulmonary edema on chest x-ray. Within the next 24 hours, the acute heart failure (AHF) progressed to the refractory cardiogenic shock with severe systemic hypotension, respiratory distress, anuria, liver congestion, and laboratory evidence of extremely high level of the anaerobic metabolism in the arterial blood (pH 7.16; HCO₃ 12.3 mmol/L; BE -14.6; lactates level 17 mmol/L). The transesophageal echo imaging showed severe dilatation and global biventricular akinesis, with left ventricular ejection fraction of 5%. The diagnosis of acute fulminant myocarditis of unknown etiology was reached. Since the patient did not respond rapidly to vasoactive and supportive therapy, MCS was immediately inserted. Broad differential diagnosis of fulminant myocarditis was considered and disseminated Borrelia infection was serologically confirmed and appropriate antimicrobial therapy was started from the fifth day after admission. MCS used over the next 26 days was successfully integrated with pharmacologic support and artificial ventilation in therapy. The patient was discharged from hospital after 65 days with a complete restoration of bilateral heart ejection fraction.

This case shows that the clinical course of the Lyme carditis can present uncommonly with profound cardiovascular collapse and the MSC implementation should be considered in the early stage of drug resistant hemodynamic instability. Rapid transfer to the cardiac center where the MCS is available for all patients with signs and symptoms of AHF due to confirmed or suspected Lyme carditis would be recommended, as this treatment could be the only life-saving method.

Lyme carditis with complete heart block: management with an external pacemaker

Timely diagnosis and prompt initiation of treatment is essential in Lyme carditis to achieve favorable prognosis. Externalized permanent pacemaker with an active fixation lead as supportive pacing modality is a feasible option till complete resolution of conduction block with continued antibiotic therapy.