Understanding how to study a complex disease

Lyme carditis, a well-established manifestation of Lyme disease, has been studied in animal models to improve understanding of its pathogenesis. This review synthesizes existing literature on these models and associated disease mechanisms. Searches in MEDLINE, Embase, BIOSIS, and Web of Science yielded 53 articles (47 mice models and 6 other animal models). Key findings include: 1) Onset of carditis correlates with spirochete localization in the heart; 2) Carditis occurs within 10 days of infection, progressing to peak inflammation within 30 days; 3) Infiltrates were predominantly composed of Mac-1+ macrophages and were associated with increases in TNF-α, IL-1 and IL-12 cytokines; 4) Resolution of inflammation was primarily mediated by lymphocytes; 5) Immune system is a double-edged sword: it can play a role in the progression and severity of carditis, but can also have a protective effect. Animal models offer valuable insights into the evolution and pathophysiologic mechanisms of Lyme carditis.

Incidence of Lyme Carditis and Lyme Carditis as a Cause of Pacemaker Implantation: A Nationwide Registry-Based Case-Control Study

Background

Lyme borreliosis (LB) of the heart is called Lyme carditis (LC), which often manifests with high-grade atrioventricular block (AVB) requiring pacemaker implantation. LC is treated with antibiotics, and most patients recover fully after treatment. The overall incidence of LC, and of LC as a cause of pacemaker implantation, has not previously been systematically studied.

Methods

This was a case-control study based on data from Swedish national registers. The study was divided into two parts; part 1 including all patients diagnosed with AVB between 2001 and 2018, and part 2 including all patients who had received a pacemaker due to AVB between 2010 and 2018. Patients diagnosed with LB 90 days before and 180 days after the AVB diagnosis were identified among the patients and compared to matched control groups generated from the general population.

Results

Of 81 063 patients with AVB, 102 were diagnosed with LB. In the control group, 27 were diagnosed with LB. The yearly incidence of LC was 0.056 per 100 000 adults and year. Of 25 241 patients who had received a pacemaker for AVB, 31 were diagnosed with LB. In the control group, 8 were diagnosed with LB. The yearly incidence of LC as a cause of pacemaker implantation was 0.033 per 100 000 adults and year. The estimated risk for patients with LC to receive a permanent pacemaker was 59%.

Conclusions

LC is a rare cause of AVB. Nevertheless, more than half of patients with LC receive a permanent pacemaker for a condition that is easily cured with antibiotics.

The Great Imitator: A Case of Lyme Carditis Mimicking ST Elevation Myocardial Infarction

Lyme disease, caused by Borrelia burgdorferi and transmitted via Ixodes ticks, is a common vector-borne illness in the United States, with an estimated 476,000 annual cases. While primarily known for its neurological and rheumatological manifestations, Lyme disease can also involve the cardiac system, known as Lyme carditis, which occurs in about 4% to 10% of cases. This case report details a rare instance of Lyme carditis presenting as ST-segment elevation myocardial infarction (STEMI) in a 31-year-old female with no significant medical history. The patient exhibited symptoms of chest pressure and shortness of breath, with laboratory results showing significantly elevated troponin levels and other indicative markers. Notably, cardiac catheterization revealed no coronary occlusion, suggesting an alternative diagnosis to acute coronary syndrome (ACS). Further testing confirmed Lyme carditis through positive serological tests for Lyme-specific IgM antibodies. The case underscores the importance of considering Lyme myopericarditis in differential diagnoses for STEMI in Lyme-endemic areas and in patients without typical risk factors for coronary artery disease. This report aims to increase clinical awareness of this condition, highlighting the need for thorough investigation in atypical cardiac presentations.

Successful permanent pacemaker explantation after diagnosis and treatment of Lyme carditis complete heart block: a case report

Background

Lyme carditis (LC) complete heart block (CHB) is typically treated with i.v. antibiotics without requiring permanent pacing. In patients with high degree atrioventricular (AV) block, suspicious index in Lyme carditis (SILC) scoring is highly sensitive for diagnosing LC.

Case summary

We present a case of CHB where a permanent pacemaker (PPM) was implanted prior to LC diagnosis. Suspicious index in Lyme carditis score was 2 at the time of exam, indicating a low risk for LC. However, per further discussion at follow-up, his score was retroactively increased to an intermediate risk of 4 and Lyme titres returned positive. An outpatient oral antibiotic regimen was given, and 2 months later, the patient had <0.1% V-pacing on interrogation with a subsequent unremarkable event monitor. The pacemaker was removed after considerations ensuring full conduction recovery. The patient is doing well at follow-up > 1 year.

Discussion

Lyme carditis spontaneous resolution of CHB is common. Once safe extraction parameters have been established, it is appropriate to engage patients without ongoing pacer requirements about explantation of their PPM. For CHB patients without clear aetiology, SILC scoring may be a predictive measure to help prevent unnecessary PPM placement in the future.

Lyme disease presenting as complete heart block in a young man: Case report and review of pathogenesis

Lyme carditis is a serious complication of Lyme disease, the most common vector-borne infection in both the United States and Northern Europe. It is a rare manifestation of Lyme disease that primarily affects young adults with a marked 3:1 male-to-female predominance. The presentation of Lyme carditis is heterogenous and often non-specific, although the most common clinical manifestation is AV block, which can be acute in onset and can rapidly progress to complete heart block. We discuss the case of a young adult male with complete heart block as a complication of Lyme infection, presenting with two episodes of syncope without prodromal symptoms months after tick bites. There are several pathogen, host and environmental factors that can play an important role in the epidemiology and pathogenesis of this serious condition that is reversible if treated in a timely manner. It is important for clinicians to be familiar with the presentation and treatment of this infection that is now being observed in a wider geographic distribution so as to avoid serious long-term complications and unnecessary permanent pacemaking implantation.

A Practical Ambulatory Approach to Atrioventricular Block Secondary to Lyme Carditis

Lyme carditis (LC) is a potentially reversible cause of complete atrioventricular (AV) dissociation that rarely requires a permanent pacemaker. The time to resolution is variable, sometimes requiring weeks, making a temporary permanent pacemaker (TPPM) a suitable bridge to recovery. We report on a 31-year-old man with serology-confirmed Lyme disease with complete heart block during the peak of the coronavirus disease 2019 pandemic. A TPPM was implanted and the patient was discharged the following day with regular follow-up in the ambulatory setting. Once 1:1 AV conduction was reestablished, the TPPM was removed. Our case demonstrates that the use of a TPPM for AV-dissociation secondary to LC is a safe and feasible strategy in select individuals which can minimize patient morbidity as well as hospital length of stay and overall health care costs.

Same-Day Carotid Artery Stenting and Coronary Artery Bypass Surgery

BACKGROUND

The optimal treatment strategy for patients with severe carotid artery disease undergoing coronary artery bypass grafting is still problematic. The important question is whether it is necessary to treat significant carotid disease in patients who have undergone coronary artery bypass grafting. This study analyzed short- and midterm results after same-day carotid artery stenting and coronary artery bypass grafting.

METHODS

From 2013 to 2020, a total of 69 patients were enrolled in the study. Same-day carotid artery stenting and coronary artery bypass grafting were performed in all patients. The study's primary end points were the evaluation rate of stroke, myocardial infarction, and death within short- and midterm periods after the procedures.

RESULTS

The 30-day mortality was 0%. The occurrences of perioperative adverse events, namely stroke, myocardial infarction, and transient ischemic attack, were 1 (1.4%), 1 (1.4%), and 4 (5.8%), respectively. Mean (IQR) follow-up time was 28 (IQR, 17-43) months. Six (8.8%) patients died during this period. Fatal stroke was registered in 2 cases, and 1 patient experienced a disabling stroke with a fatal outcome. The other 3 patients died because of chronic renal disease, a traffic accident, and for an unknown reason, respectively. Midterm survival in the group was 91.2%.

CONCLUSION

The study showed that same-day carotid artery stenting and coronary artery bypass grafting for concomitant carotid and coronary disease treatment could be a promising and feasible therapeutic strategy.

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.

Lyme carditis presenting as paroxysmal junctional tachycardia and complete atrioventricular block in an adolescent

We describe a case of a previously healthy adolescent who presented with junctional tachycardia and complete atrioventricular (AV) block due to Lyme carditis. The simultaneous presence of these findings suggested significant inflammation of the AV junction. Junctional tachycardia, particularly if seen in a patient with conduction abnormalities and potential tick exposure, should increase suspicion for Lyme carditis.

Descriptive Data on Trends Among Patients Hospitalized With Lyme Disease in Southwest Michigan, 2017-2021

This retrospective chart review identifies hospitalizations for Lyme disease at two southwest Michigan hospital systems, 2017-2021. Lyme admissions increased sharply, while admissions for Lyme carditis and neuroborreliosis increased in parallel. Southwest Michigan is becoming an endemic area for Lyme disease.

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.

Lyme Carditis Presenting With Complete Heart Block and Wide Complex Escape Rhythm

A 19-year-old woman with newly diagnosed Lyme disease presented with complete heart block and an accompanying escape rhythm with a right bundle branch block morphology. With antibiotics, her dysrhythmia resolved completely within 24 hours of presentation. This case highlights an unusual electrocardiographic manifestation of Lyme carditis.

First-degree atrioventricular block in 14-year-old child due to Lyme disease

Lyme disease is an infectious disease caused by bacteria of the Borrelia burgdorferi sensu lato (Bbsl) complex and is characterized by predominant lesions of the skin, cardiovascular system, nervous system and musculoskeletal system. We have described a clinical case of first-degree atrioventricular block in a 14-year-old boy caused by Lyme borreliosis. The disease started with the manifestations of cardiovascular system involvement. The patient and his parents did not recall observing a tick bite or manifestation of erythema migrans (EM). The boy was prescribed doxycycline. Three weeks after antibiotic therapy a second ECG examination was performed and showed no abnormalities.

Fulminant Lyme myocarditis without any other signs of Lyme disease in a 37-year-old male patient with microscopic polyangiitis-a case report

Background

Lyme disease is a tick-borne multisystem infection. The most common cardiac manifestation is an acute presentation of Lyme carditis, which often manifests as conduction disorder and rarely as myocarditis.

Case summary

We report the case of a 37-year-old male with a history of microscopic polyangiitis receiving immunosuppressive therapy. He was admitted for severe dyspnoea secondary to acute heart failure. Echocardiography and cardiac magnetic resonance imaging indicated a severely reduced left ventricular ejection fraction (LVEF) with global hypokinesia. Coronary heart disease was excluded, and endomyocardial biopsies (EMB) were performed. The left ventricular EMB revealed a rare case of fulminant Lyme carditis with evidence of typical lymphocytic myocarditis. Borrelia afzelii-DNA was detected without any relevant atrioventricular blockage or systemic signs of Lyme disease. The patient had no clinically apparent tick-borne infection or self-reported history of a tick bite. Immunological testing revealed a positive ELISA and Immunoblot for anti-Borrelia immunoglobulin G antibodies. After specific intravenous antibiotic therapy and optimized medical therapy for heart failure, the LVEF recovered, and the patient could be discharged in an improved condition. Repeat EMB a few months later revealed a dramatic regression of the cardiac inflammation and absence of Borrelia DNA in the myocardium.

Discussion

A severely reduced LVEF can be the primary manifestation of Lyme disease even without typical systemic findings and can have a favourable prognosis with antibiotic treatment. A thorough workup for Lyme carditis is required in patients with unexplained heart failure, particularly with EMB, especially in immunosuppressed patients.

Measurement of High Sensitivity Troponin T in Patients with Early Stage Lyme Disease: Preliminary Evidence for Possible Subclinical Cardiac Involvement

OBJECTIVE

In patients with early Lyme disease (ELD), cardiac involvement is known to occur in approximately 1% of patients. We measured high-sensitivity troponin T (hsTnT) in patients with early Lyme disease to evaluate the possibility of subclinical cardiac involvement.

METHODS

We measured hsTnT in 41 patients with well characterized ELD.

RESULTS

A total of 6/41 (14.6%) of patients exhibited hsTnT values above either the gender specific or gender neutral 99^th percentile cutoff for a normal hsTnT. One patient had a value greater than the cutoff used for acute myocardial infarction.

CONCLUSIONS

There are many possible explanations for increased hsTnT values in different types of patients in the absence of acute cardiac damage. Nonetheless our results raise the possibility that subclinical cardiac involvement may be more common in ELD than previously recognized. Further studies will be necessary to elucidate the significance of this finding.

Lyme Carditis Complicated by Polymorphic Ventricular Tachycardia and Cardiac Arrest: A Case Report

Lyme disease is commonly encountered in endemic areas of the United States harboring the causal organism Borrelia burgdorferi. Lyme carditis can manifest in early disseminated infections, usually as atrioventricular nodal blockade. Timely antibiotic therapy typically suppresses myocardial inflammation and reverses cardiac conduction disturbances. We present a case of a previously healthy male who presented to the emergency department with non-prodromal syncope, multifocal annular rashes, and antecedent inflammatory knee pain and effusion, found to have positive 2-tier Lyme testing and pause-dependent polymorphic ventricular tachycardia leading to cardiac arrest. Lyme carditis occurs in early disseminated infections but rarely leads to cardiac arrest. Acute management is entrained in well-established guidelines for therapy, and together with risk stratification scoring can be considered by emergency care physicians in the workup of undifferentiated syncope with concern for Lyme disease with cardiac involvement.

A rare and reversible cause of third-degree atrioventricular block: a case report

Background

Cardiac involvement of Lyme disease (LD) typically results in atrioventricular (AV) conduction disturbance, mainly third-degree AV block.

Case summary

A 54-year-old patient presented to our emergency department due to recurrent syncope. Third-degree AV block with a ventricular escape rhythm (33 b.p.m.) was identified as the underlying rhythm. Transthoracic echocardiography (TTE) was normal. To rule out common reversible causes of complete AV block, a screening test for Lyme borreliosis was carried out. Elevated levels for borrelia IgG/IgM were found and confirmed by western blot analysis. Lyme carditis (LC) was postulated as the most likely cause of the third-degree AV block given the young age of the patient. Initiation of antibiotic therapy with ceftriaxone resulted in a gradual normalization of the AV conduction with stable first-degree AV block on Day 6 of therapy. The patient was changed on oral antibiotics (doxycycline) and discharged without a pacemaker. After 3 months, the AV conduction recovered to normal.

Discussion

Lyme carditis should always be considered, particularly in younger patients with new-onset AV block and without evidence of structural heart disease. Atrioventricular block recovers in the majority of cases after appropriate antibiotic treatment.

A curious case of Lyme carditis in an urban hospital

Lyme carditis (LC), a manifestation of early disseminated Lyme disease, most commonly presents with cardiac conduction abnormalities. It is a transient condition with good prognosis but in extremely rare cases may be life-threatening. We describe a 42-year-old man who presented with progressively worsening generalized weakness, presyncope and dyspnea on exertion for 2 weeks after sustaining a tick bite. He subsequently developed a ‘bull’s eye rash’ on his flank 2 days before his presentation. He was found to have symptomatic third-degree AV conduction blockade with a ventricular escape rhythm resulting in a brief cardiac arrest. Intravenous (IV) ceftriaxone was commenced empirically and a temporary transvenous pacemaker was placed. In a few days he showed dramatic, rapid improvement; the pacemaker was removed, and the patient was discharged on oral doxycycline to complete a 24-day course. This case is unique due to its occurrence in an urban hospital where such cases are uncommon. Cardiac arrest, although brief in this case, is a rare occurrence. Lyme carditis was a surprise diagnosis in our hospital due to the patient’s geographical dislocation during the COVID-19 pandemic.

The Value of the Surface ECG for the Diagnosis and Management of Lyme Carditis: A Case Report

Lyme carditis (LC) is an early-disseminated manifestation of Lyme disease, most commonly presenting as a high-degree atrioventricular block (AVB). The degree of AVB can fluctuate rapidly within minutes, and progression to third-degree AVB is potentially fatal if not recognized and managed promptly. However, the AVB in LC is often transient and usually resolves with appropriate antibiotic therapy. LC should be on the differential diagnosis in young patients presenting with new high-degree AVB and factors that increase the index of suspicion for Lyme disease. The Suspicious Index in Lyme Carditis (SILC) score helps clinicians risk-stratify for LC. A systematic approach to the diagnosis and treatment of LC minimizes the unnecessary implantation of permanent pacemakers.

Chest palpitations in a teenager as an unusual presentation of Lyme disease: case report

BACKGROUND

The incidence of Lyme disease (LD) in North America has increased substantially in the past two decades. Concomitant with the increased incidence of infection has been an enhancement in the recognition of LD complications. Here, we report a case of Lyme carditis complicated by heart block in a pediatric patient admitted to our children's hospital. What is unique about this case is that the complaint of chest palpitations is an infrequent presentation of LD, and what it adds to the scientific literature is an improved understanding of LD in the pediatric population.

CASE PRESENTATION

The patient was a 16-year-old male who presented with the main concerns of acute onset of palpitations and chest pain. An important clinical finding was Erythema migrans (EM) on physical exam. The primary diagnoses were LD with associated Lyme carditis, based on the finding of 1st degree atrioventricular heart block (AVB) and positive IgM and IgG antibodies to Borrelia burgdorferi. Interventions included echocardiography, electrocardiography (EKG), and intravenous antibiotics. The hospital course was further remarkable for transition to 2nd degree heart block and transient episodes of complete heart block. A normal sinus rhythm and PR interval were restored after antibiotic therapy and the primary outcome was that of an uneventful recovery.

CONCLUSIONS

Lyme carditis occurs in < 5% of LD cases, but the "take-away" lesson of this case is that carditis can be the presenting manifestation of B. burgdorferi infection in pediatric patients. Any patient with suspected Lyme carditis manifesting cardiac symptoms such as syncope, chest pain, or EKG changes should be admitted for parenteral antibiotic therapy and cardiac monitoring. The most common manifestation of Lyme carditis is AVB. AVB may manifest as first-degree block, or may present as high-grade second or third-degree block. Other manifestations of Lyme carditis may include myopericarditis, left ventricular dysfunction, and cardiomegaly. Resolution of carditis is typically achieved through antibiotic administration, although pacemaker placement should be considered if the PR interval fails to normalize or if higher degrees of heart block, with accompanying symptoms, are encountered. With the rising incidence of LD, providers must maintain a high level of suspicion in order to promptly diagnose and treat Lyme carditis.

Diagnosing Lyme Carditis Presenting With Complete Heart Block

Diagnosing self-limited conduction abnormality of Lyme carditis in absence of pathognomonic skin rash or history of tick bite is challenging but necessary to avoid placement of pacemaker particularly in young patients. High degree of clinical suspicion, rapidly progressing conduction block and prompt response to antibiotics may help in diagnosis.

Chagas' cardiomyopathy and Lyme carditis: Lessons learned from two infectious diseases affecting the heart

Chagas' disease and Lyme disease are two endemic, vector-borne zoonotic infectious diseases that impact multiple organ systems, including the heart. Chagas' cardiomyopathy is a progressive process that can evolve into a dilated cardiomyopathy and heart failure several decades after the acute infection; in contrast, although early-disseminated Lyme carditis has been relatively well characterized, the sequelae of Lyme disease on the heart are less well-defined. A century of research on Chagas' cardiomyopathy has generated compelling data for pathophysiological models, evaluated the efficacy of therapy in large randomized controlled trials, and explored the social determinants of health impacting preventative measures. Recognizing the commonalities between Chagas' disease and Lyme disease, we speculate on whether some of the lessons learned from Chagas' cardiomyopathy may be applicable to Lyme carditis.

Increasing Burden of Lyme Carditis in United States Children's Hospitals

We sought to characterize the shifting epidemiology and resource utilization of Lyme disease and associated carditis in US children's hospitals. We hypothesized that the Lyme carditis burden has increased and that hospitalizations for Lyme carditis are costlier than those for Lyme disease without carditis. The PHIS database was queried for Lyme disease encounters between January 1, 2007 and December 31, 2013. Additional diagnostic codes consistent with carditis identified Lyme carditis cases. Demographic, clinical, and resource utilization data were analyzed. All costs were adjusted to 2014 US dollars. Lyme disease was identified in 3620 encounters with 189 (5%) associated with carditis. Lyme disease (360 cases in 2007 vs. 672 in 2013, p = 0.01) and Lyme carditis (17 cases in 2007 vs. 40 in 2013, p = 0.03) both significantly increased in frequency. This is primarily accounted for by their increase within the Midwest region. Carditis frequency among cases of Lyme disease was stable (p = 0.15). Encounters for Lyme carditis are dramatically costlier than those for Lyme disease without carditis [median $9104 (3741-19,003) vs. 922 (238-4987), p < 0.001] The increase in Lyme carditis cases in US children's hospitals is associated with an increased Lyme disease incidence, suggesting that there has not been a change in its virulence or cardiac tropism. The increasing number of serious cardiac events and costs associated with Lyme disease emphasize the need for prevention and early detection of disease and control of its spread.

Lyme carditis presenting as sick sinus syndrome

Lyme disease, a tickborne infection caused by Borrelia burgdorferi, can affect cardiac tissue causing Lyme carditis. Patients with Lyme carditis most commonly present with varying degrees of atrioventricular block and rarely with sick sinus syndrome. A previously healthy 22 year-old male presented with syncope. His 2 week Holter monitor showed sinus pauses of 6.5 and 6.8 s. Lyme serology, including Western blot, was positive. A stress test, completed after 8 days of intravenous antibiotics for Lyme carditis, revealed no conduction abnormalities. He was discharged on 3 weeks of oral antibiotics and had no conduction abnormalities on subsequent follow-up.

Diagnosis and Treatment of Lyme Carditis: JACC Review Topic of the Week

The incidence of Lyme disease, a tick-borne bacterial infection, is dramatically increasing in North America. The diagnosis of Lyme carditis (LC), an early disseminated manifestation of Lyme disease, has important implications for patient management and preventing further extracutaneous complications. High-degree atrioventricular block is the most common presentation of LC, and usually resolves with antibiotic therapy. A systematic approach to the diagnosis of LC in patients with high-degree atrioventricular block will facilitate the identification of this usually transient condition, thus preventing unnecessary implantation of permanent pacemakers in otherwise healthy young individuals.

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.

Advanced Heart Block in Children with Lyme Disease

BACKGROUND

The clinical course of children with advanced heart block secondary to Lyme disease has not been well characterized.

OBJECTIVE

To review the presentation, management, and time to resolution of heart block due to Lyme disease in previously healthy children.

METHODS

An IRB approved single-center retrospective study was conducted of all patients < 21 years old with confirmed Lyme disease and advanced second or third degree heart block between 2007 and 2017.

RESULTS

Twelve patients (100% male) with a mean age of 15.9 years (range 13.2-18.1) were identified. Six patients (50%) had mild to moderate atrioventricular valve regurgitation and all had normal biventricular function. Five patients had advanced second degree heart block and 7 had complete heart block with an escape rate of 20-57 bpm. Isoproterenol was used in 4 patients for 3-4 days and one patient required transvenous pacing for 2 days. Patients were treated with 21 days (n = 6, 50%) or 28 days (n = 6, 50%) of antibiotics. Three patients received steroids for 3-4 days. Advanced heart block resolved in all patients within 2-5 days, and all had a normal PR interval within 3 days to 16 months from hospital discharge.

CONCLUSION

Symptomatic children who present with new high-grade heart block from an endemic area should be tested for Lyme disease. Antibiotic therapy provides quick and complete resolution of advanced heart block within 5 days, while steroids did not appear to shorten the time course in this case series. Importantly, no patients required a permanent pacemaker.

A tick beat in the electrocardiogram: Persistent third degree block as only manifestation of Lyme disease

Lyme disease is the most common tick-borne illness in North America. A 23-year-old female presented to our emergency department with a chief complaint of sudden dyspnea and chest pain. An electrocardiogram revealed a third degree heart block. She was a resident of the Northeast region of Mexico and referred a recent travel to an endemic area for Borrelia burgdorferi in the center of Mexico in the past weeks. Lyme carditis was diagnosed after enzyme linked immunosorbent assay for IgM antibodies against B. burgdorferi was reported positive and corroborated by a confirmatory immunoblot analysis. Persistent AV block was the only manifestation in our patient, a presentation scarcely reported in literature.

Suspicious index in Lyme carditis: Systematic review and proposed new risk score

BACKGROUND

Lyme carditis (LC), an early manifestation of Lyme disease that most commonly presents as high-degree atrioventricular block (AVB), usually resolves with antibiotic treatment. When LC is not identified as the cause of AVB, a permanent pacemaker may be inappropriately implanted in a reversible cardiac conduction disorder.

HYPOTHESIS

The likelihood that a patient's high-degree AVB is caused by LC can be evaluated by clinical characteristics incorporated into a risk stratification tool.

METHODS

A systematic review of all published cases of LC with high-degree AVB, and five cases from the authors' experience, was conducted. The results informed the development of a new risk stratification tool, the Suspicious Index in LC (SILC) score. The SILC score was then applied to each case included in the review.

RESULTS

Of the 88 cases included, 51 (58%) were high-risk, 31 (35.2%) intermediate-risk, and 6 (6.8%) low-risk for LC according to the SILC score (sensitivity 93.2%). For the subset of 32 cases that reported on all SILC variables, 24 (75%) cases were classified as high-risk, 8 (25%) intermediate-risk, and 0 low-risk (sensitivity 100%). Specificity could not be assessed (no control group). Notably, 6 of the 11 patients who received permanent pacemakers had reversal of AVB with antibiotic treatment.

CONCLUSION

The SILC risk score and COSTAR mnemonic (constitutional symptoms; outdoor activity; sex = male; tick bite; age < 50; rash = erythema migrans) may help to identify LC in patients presenting with high-degree AVB, and ultimately, minimize the implantation of unnecessary permanent pacemakers.

Systematic Approach to the Diagnosis and Treatment of Lyme Carditis and High-Degree Atrioventricular Block

Lyme carditis (LC) is a manifestation of the early disseminated stage of Lyme disease and often presents as high-degree atrioventricular (AV) block. High-degree AV block in LC can be treated with antibiotics, usually resolving with a highly favorable prognosis, thus preventing the unnecessary implantation of permanent pacemakers. We present a systematic approach to the diagnosis and management of LC that implements the Suspicious Index in Lyme Carditis (SILC) risk stratification score.

Reversible atrioventricular block and the importance of close follow-up: Two cases of Lyme carditis

Lyme carditis is an uncommon presentation of the early-disseminated phase of Lyme disease, although it is recognizable and often curable. Because of its rarity, diagnosing Lyme carditis requires a high level of suspicion, especially when young patients in certain endemic areas present with symptoms of bradycardia and/or evidence of high-degree atrioventricular (AV) block. Temporary cardiac pacing along with antibiotic therapy has been shown to aid in the management of Lyme carditis until symptoms and conduction blocks have resolved. Herein, we report two cases of Lyme carditis-induced AV block that were successfully managed and reversed with temporary cardiac pacing and antibiotics. In order to monitor for any late sequela that may arise, we also recommend close follow-up for patients treated for Lyme carditis with high-degree AV block. <Learning objective: Lyme carditis manifests as a conduction system disease, predominantly involving the atrioventricular (AV) node. It can present without the classical signs of Lyme disease. It is critical to have a high suspicion of Lyme carditis in patients who present with symptoms of bradycardia or high-degree AV block in high prevalence areas. Early initiation of antibiotics, along with external temporary pacing, dramatically improves mortality rates. Close follow-up is important in patients that develop high-degree AV block.>.

Lyme carditis: Early occurrence and prolonged recovery

Lyme carditis is an uncommon manifestation of early disseminated Lyme disease. This case illustrates a 66-year-old male with complaints of fatigue, myalgias, and fever after a tick bite 3days earlier. A large erythema migrans was found on the chest wall. Initial electrocardiogram showed sinus rhythm with second degree 2:1 atrioventricular (AV) block, which progressed to intermittent complete AV block rapidly. He was treated with intravenous ceftriaxone. Over the course of 2-weeks of antibiotic therapy, the intermittent high-grade AV block improved slowly and progressively. This case highlights the importance of timely diagnosis and appropriate management to achieve a favorable prognosis.

Early Disseminated Lyme Disease Masquerading as Mononucleosis: A Case Report

BACKGROUND

Disseminated Lyme disease can be difficult to diagnose, as it begins with nonspecific signs and symptoms, which, if not treated correctly, can lead to atrioventricular conduction blocks and meningitis. In addition, the diagnosis can be further complicated by potentially false-positive test results.

CASE REPORT

We report a case of early-disseminated Lyme disease presenting with Borrelia meningitis and concomitant Lyme carditis, which was misdiagnosed as mononucleosis. A young, previously healthy patient had been hiking in the woods of upstate New York and 4 weeks later developed fever, night sweats, and myalgias. He was diagnosed with mononucleosis via a positive rapid heterophile agglutination antibody test to the Epstein-Barr virus at a walk-in clinic and was started on medications, but then subsequently developed left hip pain, a facial droop, and a very long first-degree atrioventricular conduction block. He went to the Emergency Department, where he had testing that confirmed disseminated Lyme disease. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case highlights the difficulty in early diagnosis of disseminated Lyme disease and how a potentially false-positive laboratory test can lead to the complications of Borrelia meningitis and Lyme carditis in untreated young healthy patients. Emergency physicians need to consider Lyme disease in patients with nonspecific signs and symptoms, especially if they have been outdoors for prolonged periods of time in Lyme-endemic areas.

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.

Lyme carditis

Lyme disease is a common disease that uncommonly affects the heart. Because of the rarity of this diagnosis and the frequent absence of other concurrent clinical manifestations of early Lyme disease, consideration of Lyme carditis demands a high level of suspicion when patients in endemic areas come to attention with cardiovascular symptoms and evidence of higher-order heart block. A majority of cases manifest as atrioventricular block. A minority of Lyme carditis cases are associated with myopericarditis. Like other manifestations of Lyme disease, carditis can readily be managed with antibiotic therapy and supportive care measures, such that affected patients almost always completely recover.

General practitioner reported incidence of Lyme carditis in the Netherlands

Background

Between 1994 and 2009, incidence rates of general practitioner (GP) consultations for tick bites and erythema migrans, the most common early manifestation of Lyme borreliosis, have increased substantially in the Netherlands. The current article aims to estimate and validate the incidence of GP-reported Lyme carditis in the Netherlands.

Methods

We sent a questionnaire to all GPs in the Netherlands on clinical diagnoses of Lyme borreliosis in 2009 and 2010. To validate and adjust the obtained incidence rate, medical records of cases of Lyme carditis reported by GPs in this incidence survey were reviewed and categorised according to likelihood of the diagnosis of Lyme carditis.

Results

Lyme carditis occurred in 0.2 % of all patients with GP-reported Lyme borreliosis. The adjusted annual incidence was six GP-reported cases of Lyme carditis per 10 million inhabitants, i.e. approximately ten cases per year in 2009 and 2010.

Conclusions

We report the first incidence estimate for Lyme carditis in the Netherlands, validated by a systematic review of the medical records. Although Lyme carditis is an uncommon manifestation of Lyme borreliosis, physicians need to be aware of this diagnosis, in particular in countries where the incidence of Lyme borreliosis has increased during the past decades.

[Lyme carditis]

Lyme disease is a multisystem infectious disease caused by the spirochete Borrelia burgdorferi. A steady increase in the number of cases is noticed both in Poland and Europe. Cardiac involvement in the course of borreliosis is relatively rare. It is estimated that it concerns about 0.5-10% of patients with Lyme disease. Cardiac involvement generally occurs in the early phase of illness. The most common manifestation of Lyme carditis are transient conduction abnormality, arrhythmias, myocarditis and pericarditis. The basic method of treatment Lyme carditis are antibiotics. The clinical course is usually benign. In most cases a complete recovery is observed. However, in a small proportion of patients dilated cardiomyopathy may occur. Furthermore, death from Lyme carditis has been reported. Lyme carditis remains a real diagnostic and therapeutic challenge for clinicians. Factors that can make the diagnosis difficult are: atypical clinical picture, negation of tick bite, the absence of erythema migrans, onset of symptoms outside the period of tick activity and negative serological results in the initial stage of the disease.

Lyme Disease: What the Wilderness Provider Needs to Know

Lyme disease is a multisystem tickborne illness caused by the spirochete Borrelia burgdorferi and is the most common vectorborne disease in the United States. Prognosis after initiation of appropriate antibiotic therapy is typically good if treated early. Wilderness providers caring for patients who live in or travel to high-incidence Lyme disease areas should be aware of the basic biology, epidemiology, clinical manifestations, and treatment of Lyme disease.

Lyme disease: a case report of a 17-year-old male with fatal Lyme carditis

Lyme disease is a systemic infection commonly found in the northeastern, mid-Atlantic, and north-central regions of the United States. Of the many systemic manifestations of Lyme disease, cardiac involvement is uncommon and rarely causes mortality. We describe a case of a 17-year-old adolescent who died unexpectedly after a 3-week viral-like syndrome. Postmortem examination was remarkable for diffuse pancarditis characterized by extensive infiltrates of lymphocytes and focal interstitial fibrosis. In the cardiac tissue, Borrelia burgdorferi was identified via special stains, immunohistochemistry, and polymerase chain reaction. The findings support B. burgdorferi as the causative agent for his fulminant carditis and that the patient suffered fatal Lyme carditis. Usually, Lyme carditis is associated with conduction disturbances and is a treatable condition. Nevertheless, few cases of mortality have been reported in the literature. Here, we report a rare example of fatal Lyme carditis in an unsuspected patient.

Diagnosis not to be missed: Lyme carditis, rare but reversible cause of complete atrioventricular block

Lyme carditis is a known cause of atrioventricular block and in most cases, atrioventricular block is reversible with appropriate antibiotic treatment. The diagnosis can be challenging if the disease is either not suspected, or if the initial cutaneous manifestation of erythema migrans is missed. It is important to diagnose Lyme carditis as the cause of complete heart block if unnecessary pacemaker implantation is to be avoided. We present a 43-year-old male who presented with complete heart block and also ill sustained ventricular tachycardia due to Lyme carditis that reversed completely with antibiotic therapy.

Third-degree heart block associated with lyme carditis: review of published cases

Lyme carditis is an uncommon manifestation of Lyme disease that most commonly involves some degree of atrioventricular conduction blockade. Third-degree conduction block is the most severe form and can be fatal if untreated. Systematic review of the medical literature identified 45 published cases of third-degree conduction block associated with Lyme carditis in the United States. Median patient age was 32 years, 84% of patients were male, and 39% required temporary pacing. Recognizing patient groups more likely to develop third-degree heart block associated with Lyme carditis is essential to providing prompt and appropriate therapy.