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 illsustained ventricular tachycardia due to Lyme carditis that reversed completely with antibiotic therapy.     

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 3 days 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.     

Lyme carditis: Sequential electrocardiographic changes in response to antibiotic therapy

Lyme disease is a tick-borne spirochetal infection that may involve heart. The cardiac manifestations of Lyme disease including varying degrees of atrioventricular heart block occur within weeks to months of the infecting tick bite. This report describes a 43 year-old man with Lyme carditis who presented with complete heart block. The heart block resolved with ceftriaxone therapy. Lyme carditis should be considered in the differential diagnosis in patients who present with new onset advanced heart block.     

Cardiac implications of Lyme disease, diagnosis and therapeutic approach

Lyme is a tick-borne disease. The genetic diversity of Borreliae its distribution worldwide and its epidemiology have been related to different clinical manifestations. Carditis is a rare manifestation of Lyme disease. The commonest abnormality is atrioventricular block of various degrees, though other rhythm abnormalities have been reported. Pericarditis, myocarditis, cardiomyopathy and degenerative valvular disease have been associated with B. burgdorferi. Temporary pacing might be required in unstable patients. The majority of the conduction disturbances have a benign prognosis, if the infectious agent is identified and treated appropriately.     

Heart stopping tick

Although Lyme carditis is relatively rare within 4-6 wk of exposure, it can uncommonly present as the first sign of disseminated Lyme disease. Here we present 17 year old boy who presented to the emergency department with chest discomfort and was later found to have complete atrioventricular block due to lyme carditis. He had uneventful recovery after empiric treatment with ceftriaxone. Our case highlights the importance of considering reversible causes of complete AV block since appropriate therapy can avoid the need for permanent pacemaker insertion.     

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.     

Sinus Pause in Association with Lyme Carditis

Lyme disease is the most prevalent tick-borne disease in the United States. It is caused by the spirochete Borrelia burgdorferi. Cardiac involvement is seen in 4% to 10% of patients with Lyme disease. The principal manifestation of Lyme carditis is self-limited conduction system disease, with predominant involvement of the atrioventricular node. On rare occasions, Lyme carditis patients present with other conduction system disorders such as bundle branch block, intraventricular conduction delay, and supraventricular or ventricular tachycardia. We report the unusual case of a 59-year-old man who presented with new-onset symptomatic sinus pauses one month after hiking in upstate New York. To our knowledge, this is the first case report from North America that describes the relationship between symptomatic sinus pause and Lyme carditis.     

His Bundle pacing for congenital complete AV block: An attempt to fix a broken heart?

Congenital complete atrioventricular block (CCAVB) is usually due to failure of atrioventricular nodal conduction with preservation of the His‐Purkinje system. Most patients with CCAVB ultimately require pacemaker therapy to restore physiologic heart rates, dealing with the detrimental effects of chronic right ventricular (RV) pacing on cardiac structure and function. The ideal stimulation pattern aims to mimic the normal conduction to restore electromechanical coupling, preventing the harmful effects of lack of atrioventricular and inter‐intraventricular synchrony. This can be done through conduction system pacing. Using His bundle pacing (HBP) for cardiac resynchronization therapy in two complete congenital atrioventricular block patients, we have reported better exercise tolerance and echocardiographic improvements related to reversible left ventricular dysfunction that can be corrected by restoration of the normal activation pathway via the His‐Purkinje network.     

Lyme Myocarditis Presenting as Fascicular Tachycardia with Underlying Complete Heart Block

Lyme Myocarditis with Fascicular Tachycardia. A case of Lyme myocarditis manifest as a fascicular tachycardia is presented. Subtle findings of heart block hi the presence of preserved ventricular function led to the correct diagnosis in this otherwise healthy patient. Treatment with ceftriaxone resolved both abnormalities.     

房室交界区双层阻滞的心电图改变与临床

目的进一步认识和评价房室交界区双层阻滞的心电图改变和临床意义。方法分析696例房室阻滞中10例房室交界区双层阻滞的资料。结果10例患者均为器质性心脏病,心电图均表现为非交替性文氏周期,其中长PR间期文氏现象(A型)及长PR间期高度房室阻滞(B型)各5例。9例出现于窦性心律,1例因药物导致房性心动过速。经异丙肾上腺素治疗4例,其中2例双层消除,1例减轻,1例因治疗无效而植入心脏起搏器;5例未用异丙肾上腺素治疗,其中2例双层阻滞消除,3例减轻。10例患者均获临床治愈或好转出院。结论非交替性文氏周期亦为房室交界区双层阻滞的常见类型,B型与A型同样多见。绝大多数出现于窦性心律,且均为病理性房室阻滞。治疗原则与单一类型房室阻滞无异,对有晕厥等症状的高度或二度房室阻滞可加用异丙肾上腺素治疗,但对预后并无显著影响,仅作为应急和过渡措施。     

Anatomy,histology, and pathology of the cardiac conduction system—part V

Although morphologic findings in many of the cardiac arrhythmias of acute and chronic disease have been elusive, the correlates of heart block (particularly atrioventricular block) are abundant. Pathologic features of sinoatrial, atrioventricular, and bundle-branch block are reviewed. Lev and Lenegre diseases (idiopathic bilateral bundle-branch fibrosis) are also reviewed.     

Location and Clinical Implications of High‐Degree Atrioventricular Block During Dipyridamole Infusion: A Case Report

We describe a patient with bifascicular block, who developed transient high‐degree atrioventricular block during dipyridamole infusion. This patient was subsequently found to have significant His‐Purkinje disease at electrophysiology study, and underwent permanent pacemaker implantation. Spontaneous atrioventricular block was documented during follow‐up. This case report raises the issue of dipyridamole safety in patients with intraventricular conduction defects, and contributes an additional mechanism to the possible explanation of dipyridamole‐induced atrioventricular block. A.N.E. 2002;7(2):174–176     

Case Report: Type I Second-Degree AV Block Masquerading as Type II Block

This report describes a patient with type I second-degree atrioventricular block and sequences consistent with type II block according to widely accepted criteria. The electrocardiograms illustrate the importance of deductive reasoning and the clinical context in the diagnostic evaluation of perplexing forms of second-degree AV block.     

Long-term Outcomes in Treated Lyme Carditis

Lyme disease is the most reported tick-borne illness in North America. Lyme carditis (LC) is an early-disseminated manifestation of Lyme disease, most commonly presenting as symptomatic high-degree atrioventricular block (AVB) which resolves with appropriate antibiotic therapy. However, long-term outcomes of treated LC have not previously been described. We present a series of 7 patients (median 28 years, 6 male) with serologically confirmed LC treated with a standard protocol developed at our center including antibiotics and pre-discharge stress test to assess AV node stability. At a mean follow-up of 20.8 months, all patients were asymptomatic, had resumed normal activities, and were free of conduction abnormalities. None required permanent pacing. Our study supports avoidance of permanent pacing for LC if conduction is stable at discharge.     

Mesothelioma of the atrioventricular node: first successful follow-up after excision.

Mesothelioma of atrioventricular nodes may cause congenital heart block and diagnosis is usually confirmed at post-mortem. Awareness of the possibility of the development of this tumour and selective coronary arteriography may help to diagnose this in life.     

Complete heart block due to lyme carditis

Lyme carditis is becoming a more frequent complication of Lyme disease, primarily due to the increasing incidence of this disease in the United States. Cardiovascular manifestations of Lyme disease often occur within 21 days of exposure and include fluctuating degrees of atrioventricular (AV) block, acute myopericarditis or mild left ventricular dysfunction and rarely cardiomegaly or fatal pericarditis. AV block can vary from first-, second-, third-degree heart block, to junctional rhythm and asystolic pauses. Patients with suspected or known Lyme disease presenting with cardiac symptoms, or patients in an endemic area presenting with cardiac symptoms with no other cardiac risk factors should have a screening electrocardiogram along with Lyme titers. We present a case of third-degree AV block due to Lyme carditis, illustrating one of the cardiac complications of Lyme disease. This disease is usually self-limiting when treated appropriately with antibiotics, and does not require permanent cardiac pacing.     

Acute rickettsial myocarditis and advanced atrioventricular block: diagnosis and treatment aided by endomyocardial biopsy

A case of acute advanced atrioventricular block in a young patient is described. An endomyocardial biopsy performed to confirm myocarditis showed findings compatible with rickettsial endomyocarditis. Treatment with tetracycline was therefore started and a rapid remission of the atrioventricular block was observed. Healing of the disease was subsequently documented by a second endomyocardial biopsy. The rickettsial etiology was confirmed by the results of serial serum titers against Proteus OX-19. Endomyocardial biopsy may be clinically indicated for the diagnosis of advanced atrioventricular block in young patients and may help in their optimal treatment.     

The RR index test for the differentiation of atrioventricular nodal block from His--Purkinje block during incremental atrial pacing in patients with bifascicular block

AIMS: His—Purkinje block induced by incremental atrial pacingis highly predictive of an impending high degree atrioventricularblock in patients with bifascicular block. The His potentialis, however, sometimes not measurable or is lost in the ventriculardepolarization. The aim of this study was to evaluate whetherthe comparison of RR intervals before and after atrioventricularblock, induced by incremental atrial pacing, could differentiatebetween atrioventricular nodal and His—Purkinje blockin patients with bifascicular block. METHODS AND RESULTS: In 98 patients with bifascicular block, incremental atrial pacingwas performed as part of an invasive electrophysiological study.An ‘RR index’ was constructed by calculating thenumerical difference between the RR interval immediately beforeand after the atrioventricular block divided by the RR intervalimmediately before the pacing-induced block. Endocavitary recordingof the His bundle potential was used for defining the levelof atrioventricular block. The median RR index was 0·98(range 0·88–1·02) in recordings with His—Purkinjeblock and 0·49 (range 0·11–0·89)in recordings with atrioventricular nodal block (P<0·001).An RR index of 0·85 had a sensitivity of 100% and a specificityof 99% for the identification of atrioventricular block localizedto the His—Purkinje system. CONCLUSION: The use of an RR index is a helpful tool in the differentiationof His—Purkinje from atrioventricular nodal block in patientswith bifascicular block undergoing incremental atrial pacingas part of an invasive electrophysical study.     

Paroxysmal Atrioventricular Block in a Relatively Young Patient with COVID-19

Cardiac involvement has been reported in patients with coronavirus disease 2019 (COVID-19). We herein report a 41-year-old man who presented with recurrent paroxysmal atrioventricular block without showing significant cardiac injuries or comorbidities. The patient was diagnosed with COVID-19 and admitted to our hospital, where he was noted to have paroxysmal atrioventricular block. Cardiac biomarkers, echocardiography, and cardiac magnetic resonance imaging findings were fairly normal. An endomyocardial biopsy performed before the implantation of a permanent pacemaker revealed mild myocardial fibrosis without inflammatory infiltrates. The unusual myocardial involvement of the novel coronavirus was suspected.     

Cardiac Conduction Abnormalities in a Mouse Model of Lyme Borreliosis

Background: Borrelia Burgdorferi(BB) induces cardiac conduction abnormalities in infected humans. Mice models of Lyme disease have been developed, however their electrophysiologic (EP) properties of conduction are unknown. Methods: Seventy-six C3H/J mice (BB infected and age- and gender-matched controls) underwent blinded in vivo EP studies. In a first phase of the study, 40 male C3H/J mice were divided into 2 groups: Group (A) mice were infected at age 3 (weeks) and studied at 5, and Group (B) mice were infected at 9 and studied at 11. In a second phase, 36 female mice were divided into 2 groups: Group (C) mice were infected at 3 weeks and studied at 5, and Group (D) mice were infected at 3 and studied at 11. Results: Infected mice of group (A) and (C) had wider QRS complexes (21.0±1.6 versus 17.3±1.3[emsp4 ]ms, p0.0001 and 20.3±2.1 versus 18.5±1.7, p = 0.05, respectively) compared to the healthy controls (HC). Infected mice of group (B) and group (D) were similar to the HC. In all groups, the presence of conduction abnormalities correlated very closely with the amount of inflammation on pathology. Conclusion: This study describes the first EP mouse model of Lyme carditis. C3H/J mice exhibit conduction abnormalities that are reversible 8 weeks after inoculation, closely paralleling the resolution of inflammation on pathology. This model can be a valuable tool in the developing and testing of new modalities for the prevention and treatment of Lyme carditis.