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Background: Immune-checkpoint inhibitor-associated myocarditis (ICI-myocarditis) often presents with arrhythmias, but the prognostic value of early electrocardiogram findings is unclear. Although ICI-myocarditis and acute cellular rejection (ACR) following cardiac transplantation use similar treatment strategies, differences in arrhythmia burden are unknown., Objective: To evaluate the association of electrocardiogram findings in ICI-myocarditis with myocarditis-related mortality and life-threatening arrhythmia., Methods: A total of 125 cases of ICI-myocarditis were identified retrospectively across 49 hospitals worldwide; 50 cases of grade 2R or 3R ACR were included as comparators. Two cardiologists blinded to clinical data interpreted electrocardiograms. Associations between electrocardiogram features, myocarditis-related mortality and the composite of myocarditis-related mortality and life-threatening arrhythmias were examined. Adjusted hazard ratios (aHRs) were calculated., Results: The cohort had 78 (62.4%) men; median (interquartile range) age was 67 (58-76) years. At 30 days, myocarditis-related mortality was 20/124 (16.1%), and 28/124 (22.6%) met the composite endpoint. Patients who developed complete heart block (aHR by subdistribution hazards model [aHR(sh)] 3.29, 95% confidence interval [CI] 1.24-8.68; P=0.02) or life-threatening cardiac arrhythmias (aHR(sh) 6.82, 95% CI: 2.87-16.21; P<0.001) had a higher risk of myocarditis-related mortality. Pathological Q waves (aHR(sh) 3.40, 95% CI: 1.38-8.33; P=0.008), low QRS voltage (aHR(sh) 6.05, 95% CI: 2.10-17.39; P<0.001) and Sokolow-Lyon index (aHR(sh)/mV 0.54, 95% CI: 0.30-0.97; P=0.04) on admission electrocardiogram were also associated with increased risk of myocarditis-related mortality. These associations were mirrored in the composite outcome analysis. Compared with ACR, ICI-myocarditis had a higher incidence of life-threatening cardiac arrhythmias (15/125 [12.0%] vs 1/50 [2%]; P=0.04) and third-degree heart block (19/125 [15.2%] vs 0/50 [0%]; P=0.004)., Conclusions: Electrocardiograms in ICI-myocarditis with ventricular tachycardias, heart block, low-voltage and pathological Q waves were associated with myocarditis-related mortality and life-threating arrhythmia. Arrhythmia burden in ICI-myocarditis exceeds that of ACR after heart transplant., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Objective: The present article aims at describing a rare case of an RP patient who evolved with heart block and was successfully treated with corticoid pulse therapy, without the need for pacemaker insertion., Patients and Methods: A systematic research on relapsing polychondritis (RP) and heart block (HB) published in PubMed/MEDLINE, Web of Sciences, LILACS, and Scielo from 1966 to August 2020 was performed., Results: It was found 10 studies on RP associated with HB, and we added a case. Most were male (7/10) with ages 30 to 66 years old. RP disease duration was 1 week-6 years. In most cases (7/10), the RP was active when the HB occurred. A complete HB was observed in 4/7, followed by type II degree block in 3/7, and one patient had a sinus node dysfunction. Most patients received glucocorticoids. A pacemaker was inserted in 4/9 cases. Good outcome was observed in 3/9 patients and mortality in 2/10., Conclusions: We report the first case of an RP patient who had a heart block and was successfully treated with methylprednisolone pulse therapy. The authors suggest that in these RP cases, an attempt with a glucocorticoid pulse therapy may be offered to treat the heart block and prevent the insertion of a pacemaker.

Background: Experimental and clinical evidence support the role of macrophage Toll-like receptor signaling in maternal anti-SSA/Ro-mediated congenital heart block (CHB)., Objectives: Hydroxychloroquine (HCQ), an orally administered Toll-like receptor antagonist widely used in lupus including during pregnancy, was evaluated for efficacy in reducing the historical 18% recurrence rate of CHB., Methods: This multicenter, open-label, single-arm, 2-stage clinical trial was designed using Simon's optimal approach. Anti-SSA/Ro-positive mothers with a previous pregnancy complicated by CHB were recruited (n = 19 Stage 1; n = 35 Stage 2). Patients received 400 mg daily of HCQ prior to completion of gestational week 10, which was maintained through pregnancy. The primary outcome was 2° or 3° CHB any time during pregnancy, and secondary outcomes included isolated endocardial fibroelastosis, 1° CHB at birth and skin rash., Results: By intention-to-treat (ITT) analysis, 4 of 54 evaluable pregnancies resulted in a primary outcome (7.4%; 90% confidence interval: 3.4% to 15.9%). Because 9 mothers took potentially confounding medications (fluorinated glucocorticoids and/or intravenous immunoglobulin) after enrollment but prior to a primary outcome, to evaluate HCQ alone, 9 additional mothers were recruited and followed the identical protocol. In the per-protocol analysis restricted to pregnancies exposed to HCQ alone, 4 of 54 (7.4%) fetuses developed a primary outcome as in the ITT. Secondary outcomes included mild endocardial fibroelastosis (n = 1) and cutaneous neonatal lupus (n = 4)., Conclusions: These prospective data support that HCQ significantly reduces the recurrence of CHB below the historical rate by >50%, suggesting that this drug should be prescribed for secondary prevention of fetal cardiac disease in anti-SSA/Ro-exposed pregnancies. (Preventive Approach to Congenital Heart Block With Hydroxychloroquine [PATCH]; NCT01379573)., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

A 53-year-old male underwent a pulmonary vein isolation (PVI) of atrial fibrillation (AF) with a second-generation cryoballoon (CB). Although the patient maintained sinus rhythm after the PVI, a superior vena cava (SVC) fibrillation was recorded by a circular-multipolar-electrode catheter positioned inside the SVC that suggested conduction block between the right atrium (RA)-SVC connection. An adenosine triphosphate intravenous injection induced a dormant reconnection of the SVC myocardial sleeve and converted sinus rhythm to an AF rhythm. This case demonstrated that a CB application for the isolation of a right superior pulmonary vein could induce an electrical conduction block between the RA-SVC connection., (© 2018 Wiley Periodicals, Inc.)

Rationale: Neonatal lupus erythematosus (NLE) is an infrequent disease caused by transplacental maternal autoantibodies. The most common effects of NLE include cutaneous involvement and congenital heart block (CHB), although it might involve multiple organs, such as the liver, lungs, blood, and nervous or digestive systems. Izmirly PM1 and Tonello et al recently reported cutaneous manifestations of neonatal lupus and risk of subsequent CHB. The most serious complication of NLE is complete atrioventricular (AV) block., Patient Concerns: We experienced 2 cases of NLE that were diagnosed in the past year in our Neonatal Intensive Care Unit. These cases showed 2 different clinical spectrums (CHB, multisystemic effects). One case was a 32-week pregnant woman with combined liver damage and fever, and her fetus was premature due to bradycardia and pericardial effusion. The second case was a young pregnant woman who had systemic lupus erythematosus for 2 years and had been taking methylprednisolone and hydroxychloroquine for a long time since her illness. When prenatal testing at 28 weeks of pregnancy showed that the fetus had CHB, the mother began taking dexamethasone., Diagnosis: The first case was diagnosed as NLE with CHB after birth, while the second was diagnosed as NLE with CHB, ductus arteriosus, and atrial septal defect when she was born at 34 weeks., Interventions: Both of 2 cases were treated with steroids, intravenous immunoglobulin, and a diuretic. But the second case was treated with isoprenaline in addition to the above., Outcomes: Both of the infants was followed up and found to be clinically normal. During the clinic follow-up of the first case, the 8-month-old infant was still asymptomatic with normal growth and development. Her heart rate fluctuated from 40 to 90 beats/minute., Lessons: Autoimmune CHB is a severe, potentially life-threatening disorder associated with passive transfer of maternal anti-Sjogren's syndrome A/Ro and anti-Sjogren's syndrome B/La autoantibodies. Mothers who are positive for these autoantibodies are recommended to have serial echocardiography and obstetric ultrasonography from the early second trimester. Newborns should be delivered at an early stage of gestation if there is evidence of pericardial effusion, ascites, increasing ventricular ectopy, reduced ventricular shortening fraction, or AV valve regurgitation. Aggressive medical management after birth should be coupled with pacemaker implantation in infants who do not respond to medical therapies alone.

Alterations of normal intra- and interatrial conduction are a common outcome of multiple cardiovascular conditions. They arise most commonly in the context of advanced age, cardiovascular risk factors, organic heart disease, atrial fibrosis, and left atrial enlargement. Interatrial block (IAB), the most frequent and extensively studied atrial conduction disorder, affects up to 20% of the general primary care population. IAB can be partial (P wave duration ≥ 120 ms on any of the 12 ECG leads) or advanced (P wave ≥ 120 ms and biphasic morphology (positive-negative) in inferior leads). Advanced IAB is an independent risk factor for supraventricular tachyarrhythmias and embolic stroke in a variety of clinical settings. Advanced IAB is a cause of left atrial electromechanical dysfunction and left atrioventricular dyssynchrony and has been associated with left ventricular diastolic dysfunction. P wave duration is associated with cardiovascular and all-cause mortality in the general population. Atrial conduction abnormalities should be identified as markers of atrial remodeling, prognostic indicators, and, in the case of advanced IAB, a true arrhythmologic syndrome. IAB and other P wave abnormalities should prompt the search for associated conditions, the treatment of which may partially reverse atrial remodeling or prevent it if administered upstream. Future studies will help define the role of preventive therapeutic interventions in high-risk patients, including antiarrhythmic drug therapy and oral anticoagulation. Implications for the treatment of heart failure and for pacing should also be further investigated.

Henoch-Schonlein purpura (HSP) is a rare, typically self-limited, multi-organ vasculitis. Cardiac involvement with HSP carries high morbidity and mortality, thus requiring early aggressive immunosuppressive therapy. We report a case of HSP complicated with acute systolic left ventricular (LV) dysfunction, symptomatic sinus bradycardia and high-grade atrio-ventricular (AV) heart block. Cyclophosphamide, a commonly used agent in HSP, was contraindicated due to the patient's presentation with acute renal failure. Treatment with monoclonal antibody rituximab and corticosteroids was initiated with an improvement in and resolution of LV systolic dysfunction, sinus bradycardia and AV block. We believe this is the first published report on rituximab treatment in HSP with cardiac involvement manifesting with severe LV systolic dysfunction, sinus bradycardia and high-grade AV block., (© 2018 Royal Australasian College of Physicians.)

Objective: Progressive cardiac conduction disease (PCCD) is a common pediatric heart conduction disorder. It is an autosomal inheritance of rare mutations, which leads to familial cases of PCCD. In these cases, the His-Purkinje system's conductive capacity is progressively deranged, involving either right or left bundle branch block. Also, QRS complexes display widening is an important characteristic that culminates in complete AV block, syncope, and sudden death. Mutations in TRPM4 gene that encodes for transient receptor potential melastatin 4 have recently been reported to cause familial cases of PCCD and heart block. TRPM4 conducts a Ca2+-activated non-selective monovalent cationic current leading to a negative plasma membrane potential. TRPM4 channels let Na+ ion influx, causing membrane depolarization, whereas, at positive membrane potentials, TRPM4 channels repolarize the membrane by facilitating K+ ion efflux from the cell. TRPM4 protein contains many regulatory motifs that confer voltage dependence, ATP/ADP sensitivity, and Ca2+ responsiveness. Mutational studies revealed the significance of the two-calmodulin binding sites at the N-terminus of for Ca2+ dependent activation of this channel. Mutations that reduce deSUMOylation increase the steady-state levels of active TRPM4 channels on the membrane without alteration of its sensitivity to Ca2+ or ATP or its voltage dependence of activation. Increased TRPM4 function interferes with cardiac conduction and eventually contributes to heart block. Both gain and loss of function mutations of TRPM4 are implicated in the cardiac block. Currently, the major therapeutic management of cardiac block due to TRPM4 mutations is implantation of a pacemaker to reinstate normal current propagation through AV node.

It is currently recommended that hydroxychloroquine (HCQ) be maintained during pregnancy in patients with systemic lupus erythematosus. Recent data suggest that this Toll-like receptor inhibitor may also reduce the recurrence rate of anti-SSA/Ro associated congenital heart block (CHB). This case report describes a unique situation in which a CHB-afflicted, HCQ-exposed pregnancy was electively terminated. The heart did not reveal any characteristic features of cardiotoxicity, providing further evidence supporting the safety of foetal exposure to HCQ.

Objective: Mothers carrying anti-Ro antibodies are frequently referred for weekly echocardiograms to early detect and treat antibody-mediated fetal heart disease. We tested a surveillance strategy based on anti-Ro antibody titers., Methods: From 2009 to 2014, 232 pregnancies were referred for maternal anti-Ro antibodies. At the baseline echocardiogram, anti-Ro titers were measured by enzyme-linked immunosorbent essay and results categorized as negative (<8 U/mL; n = 43; excluded), low-moderate positive (8-49 U/mL; n = 62; group 1) or high positive (50 - >100 U/mL; n = 127; group 2). Serial echocardiograms to ≥24 weeks were only recommended for group 2 mothers., Results: Group 1 patients underwent significantly less fetal echocardiograms when compared with group 2 mothers (median 2 vs. 4; p < 0.001). Isolated endocardial fibroelastosis (n = 1) and incomplete (n = 4) or complete (n = 4) heart block were diagnosed in 9 (8%) pregnancies with anti-Ro titers >100 U/mL but none with lower titers (odds ratio 17.78; p = 0.004). Incomplete block and endocardial fibroelastosis regressed with transplacental corticosteroid and immune globulin therapy., Conclusions: Limiting serial fetal echocardiograms to women with high anti-Ro antibody levels is safe and more cost effective. While numbers of echocardiograms were significantly reduced in referrals with anti-Ro titers <50 U/mL, reversible abnormalities with prenatal treatment were detected by serial echocardiography in group 2 patients. © 2017 John Wiley & Sons, Ltd., (© 2017 John Wiley & Sons, Ltd.)

Objectives: Extension of disease beyond the atrioventricular (AV) node is associated with increased mortality in cardiac neonatal lupus (NL). Treatment of isolated heart block with fluorinated steroids to prevent disease progression has been considered but published data are limited and discordant regarding efficacy. This study evaluated whether fluorinated steroids given to manage isolated advanced block prevented development of disease beyond the AV node and conferred a survival benefit., Methods: In this retrospective study of cases enrolled in the Research Registry for NL, inclusion was restricted to anti-SSA/Ro-exposed cases presenting with isolated advanced heart block in utero who either received fluorinated steroids within 1 week of detection (N=71) or no treatment (N=85). Outcomes evaluated were: development of endocardial fibroelastosis, dilated cardiomyopathy and/or hydrops fetalis; mortality and pacemaker implantation., Results: In Cox proportional hazards regression analyses, fluorinated steroids did not significantly prevent development of disease beyond the AV node (adjusted HR=0.90; 95% CI 0.43 to 1.85; p=0.77), reduce mortality (HR=1.63; 95% CI 0.43 to 6.14; p=0.47) or forestall/prevent pacemaker implantation (HR=0.87; 95% CI 0.57 to 1.33; p=0.53). No risk factors for development of disease beyond the AV node were identified., Conclusions: These data do not provide evidence to support the use of fluorinated steroids to prevent disease progression or death in cases presenting with isolated heart block., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Cardiac arrhythmias are an important aspect of fetal and neonatal medicine. Premature complexes of atrial or ventricular origin are the main cause of an irregular heart rhythm. The finding is typically unrelated to an identifiable cause and no treatment is required. Tachyarrhythmia most commonly relates to supraventricular reentrant tachycardia, atrial flutter, and sinus tachycardia. Several antiarrhythmic agents are available for the perinatal treatment of tachyarrhythmias. Enduring bradycardia may result from sinus node dysfunction, complete heart block and nonconducted atrial bigeminy as the main arrhythmia mechanisms. The management and outcome of bradycardia depend on the underlying mechanism., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Dysfunction of pacemaker activity in the sinoatrial node (SAN) underlies "sick sinus" syndrome (SSS), a common clinical condition characterized by abnormally low heart rate (bradycardia). If untreated, SSS carries potentially life-threatening symptoms, such as syncope and end-stage organ hypoperfusion. The only currently available therapy for SSS consists of electronic pacemaker implantation. Mice lacking L-type Cav1.3 Ca(2+) channels (Cav1.3(-/-)) recapitulate several symptoms of SSS in humans, including bradycardia and atrioventricular (AV) dysfunction (heart block). Here, we tested whether genetic ablation or pharmacological inhibition of the muscarinic-gated K(+) channel (IKACh) could rescue SSS and heart block in Cav1.3(-/-) mice. We found that genetic inactivation of IKACh abolished SSS symptoms in Cav1.3(-/-) mice without reducing the relative degree of heart rate regulation. Rescuing of SAN and AV dysfunction could be obtained also by pharmacological inhibition of IKACh either in Cav1.3(-/-) mice or following selective inhibition of Cav1.3-mediated L-type Ca(2+) (ICa,L) current in vivo. Ablation of IKACh prevented dysfunction of SAN pacemaker activity by allowing net inward current to flow during the diastolic depolarization phase under cholinergic activation. Our data suggest that patients affected by SSS and heart block may benefit from IKACh suppression achieved by gene therapy or selective pharmacological inhibition.

The objective of this study was to describe the clinical and immunological characteristics of maternal autoimmune-mediated fetal congenital heart block (CHB) in a cohort of pregnant women from an autoimmune disease pregnancy clinic. This is a retrospective observational study of all women presenting with CHB in our autoimmune disease pregnancy clinic from January 1997 to December 2014. In addition, perinatal outcome is also described. Fourteen patients accounting for 18 fetuses with CHB were identified. The median age was 32.5 years (range, 22-40). Seven (50 %) patients had Sjögren's syndrome, and the remaining seven were asymptomatic carriers of autoantibodies. All patients had anti-Ro/SSA antibodies, and 11/13 (85 %) had anti-La/SSB antibodies. The median gestational age at the time of CHB was 22 weeks (range 18-28). Complete third degree CHB was detected in 12 (67 %). Seven cases of CHB were treated with dexamethasone, two with ritodrine, and one with the association of dexamethasone, ritodrine, and terbutaline. In 9 (50 %) cases that presented with, or developed, very poor prognosis factors, such as a ventricular rate below 50-55 bpm and/or the presence of fetal hydrops, parents opted for the termination of pregnancy, after dedicated counseling. Finally, there were nine newborns (seven males [78 %]) with median age at delivery of 37 weeks (range, 32-39). A definitive epicardial pacemaker was placed in six newborns, four of them within 2 weeks of life. CHB is a severe complication related to maternal anti-Ro/SSA and anti-La/SSB antibodies. Our results confirm previous data showing that therapy is ineffective, and most of the surviving patients will require neonatal pacemaker.

The molecular pharmacology of the G protein-coupled receptors for sphingosine 1-phosphate (S1P) provides important insight into established and new therapeutic targets. A new, potent bitopic S1P3 antagonist, SPM-354, with in vivo activity, has been used, together with S1P3-knockin and S1P3-knockout mice to define the spatial and functional properties of S1P3 in regulating cardiac conduction. We show that S1P3 is a key direct regulator of cardiac rhythm both in vivo and in isolated perfused hearts. 2-Amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol in vivo and S1P in isolated hearts induced a spectrum of cardiac effects, ranging from sinus bradycardia to complete heart block, as measured by a surface electrocardiogram in anesthetized mice and in volume-conducted Langendorff preparations. The agonist effects on complete heart block are absent in S1P3-knockout mice and are reversed in wild-type mice with SPM-354, as characterized and described here. Homologous knockin of S1P3-mCherry is fully functional pharmacologically and is strongly expressed by immunohistochemistry confocal microscopy in Hyperpolarization Activated Cyclic Nucleotide Gated Potassium Channel 4 (HCN4)-positive atrioventricular node and His-Purkinje fibers, with relative less expression in the HCN4-positive sinoatrial node. In Langendorff studies, at constant pressure, SPM-354 restored sinus rhythm in S1P-induced complete heart block and fully reversed S1P-mediated bradycardia. S1P3 distribution and function in the mouse ventricular cardiac conduction system suggest a direct mechanism for heart block risk that should be further studied in humans. A richer understanding of receptor and ligand usage in the pacemaker cells of the cardiac system is likely to be useful in understanding ventricular conduction in health, disease, and pharmacology., (Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.)

An 85-year-old man with persistent atrial flutter (AFL) with slow ventricular rate of 44/min, causing fatigue and presyncope, was referred for urgent treatment. In spite of thromboembolic risk scale value 4, he had not been treated with anticoagulants because of high risk of bleeding. The decision was made to perform urgent catheter ablation to interrupt and cure AFL. Intracardiac echocardiography probe was placed in the pulmonary artery and visualized left atrial appendage free from thrombus with its proper function. Heparin was administered and AFL stopped during energy application. Intracardiac echocardiography showed immediate thrombus formation in left atrial appendage owing to complete atrial standstill and no retrograde conduction during hemodynamically effective escape nodal rhythm. This case report shows that in patients with sinus node disease effective ablation of AFL with escape rhythm without retrograde conduction to the atria may result in complete 'electrically induced' atrial standstill and immediate thrombus formation.

Background: Complete heart block (CHB) caused by myocardial inflammation is a serious consequence of cardiac sarcoidosis (CS) that requires early diagnosis for effective anti-inflammatory treatment., Objective: This study aimed to clarify the cardiac magnetic resonance imaging (MRI) and (18)F-fluoro-2-deoxyglucose positron emission tomography ((18)F-FDG PET) manifestations of newly diagnosed CS with CHB and to assess whether certain imaging features could predict responders to corticosteroid therapy., Methods: Fifteen newly diagnosed CS patients with CHB and 17 without CHB were examined. We defined abnormal (18)F-FDG uptake on (18)F-FDG PET and increased T2-weighted signal on cardiac MRI as signs of myocardial inflammation and delayed enhancement (DE) on cardiac MRI as a sign of myocardial fibrosis. Ten CHB+ patients were then treated with corticosteroids., Results: The CHB+ group showed higher (18)F-FDG uptake and increased T2-weighted signal in the interventricular septum, which involves the electrical pathway of atrioventricular conduction, than the CHB- group (P = .001 and P < .0001, respectively), whereas there was no group difference in DE (P = .232). Six corticosteroid-treated patients recovered from CHB; all had exhibited increased T2-weighted signal, (18)F-FDG uptake, and DE in the interventricular septum before therapy. In contrast, among the 4 patients without recovery, 2 showed no abnormal (18)F-FDG uptake and 3 had no increased T2-weighted signal in the interventricular septum, but all showed DE. The 2 patients without recovery with abnormal (18)F-FDG uptake showed wall thinning in the interventricular septum., Conclusion: Focal inflammation in the interventricular septum was associated with CHB and might predict recovery from CHB after corticosteroids if it coexists with preserved wall thickness., (Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Left ventricular noncompaction (LVNC) is a cardiomyopathy with hypertrabeculation of the LV, often complicated by heart failure, arrhythmia and thromboembolic events. The features of LVNC are still incompletely characterized due to its late recognition as clinically relevant condition. The aims of this study were to describe echocardiographic and electrophysiologic characteristics of LVNC patients and to assess the effects of chronic β-blocker treatment. Study patients (n = 20; 42.5 [36.3; 52.5] years; 12 men) exhibited reduced LV ejection fraction (median LVEF = 32 %) and an increased LV mass of 210 g. Sinus rhythm was present in 19 patients, whereas one patient was in atrial fibrillation. Baseline heart rate was 77.5 beats per minute. Left bundle branch block was detected in five cases. In a subgroup of patients receiving β-blocker therapy (n = 17), LV mass was reduced from 226 [178; 306] g to 220 [169; 254] g (p = 0.007) at 13 ± 6 months follow-up. By contrast, a subgroup of three patients that were not treated with an anti-β-adrenergic agent showed LV mass increase from 180 [169; 197] g to 199 [185; 213] g (p = 0.023). LVEF and electrocardiographic parameters were not significantly modulated during chronic β-blocker treatment. There was no sustained symptomatic ventricular tachyarrhythmia, thromboembolic event or death in either group. In conclusion, this study reveals reduction of LV mass among LVNC patients during β-blocker therapy. Effects of β-blocker treatment in LVNC require validation in prospective controlled studies.

Molecular technologies have produced diverse arrays of animal models for studying genetic diseases and potential therapeutics. Many have neonatal phenotypes. Spinal muscular atrophy (SMA) is a neuromuscular disorder primarily affecting children, and is of great interest in translational medicine. The most widely used SMA mouse models require all phenotyping to be performed in neonates since they do not survive much past weaning. Pre-clinical studies in neonate mice can be hindered by toxicity and a lack of quality phenotyping assays, since many assays are invalid in pups or require subjective scoring with poor inter-rater variability. We find, however, that passive electrocardiography (ECG) recording in conscious 11-day old SMA mice provides sensitive outcome measures, detecting large differences in heart rate, cardiac conduction, and autonomic control resulting from disease. We find significant drug benefits upon treatment with G418, an aminoglycoside targeting the underlying protein deficiency, even in the absence of overt effects on growth and survival. These findings provide several quantitative physiological biomarkers for SMA preclinical studies, and will be of utility to diverse disease models featuring neonatal cardiac arrhythmias.

Objective: To determine the impact of prenatal exposure to maternal anti-Ro antibodies, slow fetal heart rate, and/or prolonged dexamethasone therapy for immune-mediated congenital atrioventricular heart block (CAVB) on the cognitive and academic performance of these children at school age., Methods: We performed a prospective, blinded assessment of the cognitive functioning of 3 cohorts of children ages 6-16 years with in utero exposure to maternal anti-Ro antibodies in the following groups: no CAVB and no prenatal dexamethasone treatment (n = 14), CAVB without prenatal treatment (n = 10), and CAVB with prenatal dexamethasone treatment (n = 16). Domains assessed included intelligence, visual perceptual and visual motor skills, auditory and visual attention, verbal learning and memory, visual memory, executive function, and behavior., Results: All cohorts scored within the normal range and were not significantly different in terms of intelligence scores, verbal comprehension, perceptional reasoning, working memory, and processing speed. For children with CAVB who were treated prenatally, there were no significant associations between the neurocognitive function scores, the minimal fetal heart rate (range 47-80 beats per minute), and either the duration (range 2-15 weeks) or dosage (range 56-824 mg) of dexamethasone therapy., Conclusion: CAVB and transplacental treatment with dexamethasone was not associated with neurocognitive impairment in school-age children. Larger numbers of children are needed to validate our observation, and assessment of other cognitive abilities is warranted., (Copyright © 2014 by the American College of Rheumatology.)

Systemic lupus erythematosus (SLE) is a multisystemic disease which potentially involves various organs including the skin, joints, kidneys, liver, hematopoetic system, and serous membranes. It is rarely seen in elderly males. The most common cardiovascular involvement type is pericarditis. Anti-Ro antibodies may be associated with neonatal lupus which causes heart blocks. Recent literature indicates that anti-Ro antibodies may be associated with various rhythm and conduction disturbances in the adulthood. The most common finding associated with anti-Ro antibodies is prolonged corrected QT (QTc) interval. Herein, we present an elderly male patient with anti-Ro-positive SLE associated with prolonged QTc interval and AV blocks that significantly improved after corticosteroid treatment.

Background: The effects and the safety of ajmaline challenge in elderly patients with suspected atrioventricular (AV) conduction disease have not been systematically investigated. The purpose of this study was to assess the response of intravenous administration of ajmaline in patients older than 75 years suspected to be affected by AV conduction disease with respect to unmask high-degree His-Purkinje block or the typical Brugada ECG pattern., Methods: Consecutive patients older than 75 years having undergone in our centre an electrophysiologic study with intravenous ajmaline administration were eligible for this study., Results: A total of 162 consecutive patients older than 75 years (84 males; mean age: 78±4 years) were included. Ajmaline induced prolongation of the H-V interval up to 100 ms or more in 25 patients (15%). High degree His-Purkinje block was produced in 5 patients (3%). Moreover, ajmaline challenge unmasked a Brugada type 1 ECG in 12 patients (7%). No ventricular tachyarrhythmia was observed during the pharmacologic challenge and no severe side effects occurred. Among the study population, 56 (34%) and 6 patients (4%) underwent a PM and ICD implantation, respectively. For the patients with BS, a family screening was performed in a total of 37 individuals. Eighteen family members (48%) presented a positive ajmaline test and 1 (3%) a spontaneous Brugada type 1 ECG., Conclusions: Ajmaline challenge in the elderly is a safe procedure to unmask AV conduction disease and can lead to an unexpected diagnosis of BS. Although the clinical impact is obvious, the therapeutic management remains controversial., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

A 52 year old patient presented with orthostatic dizziness and syncope caused by postural heart block. When the patient was supine, atrioventricular conduction was normal but when she assumed the upright posture she developed advanced atrioventricular block rapidly progressing to complete heart block. We are presenting a case of syncope caused by orthostatic heart block.

Aims: To assess the efficacy of autologous biological pacing function by autograft of gene-transferred mesenchymal stem cells in a porcine model of complete heart block., Methods and Results: Fourteen healthy young male pigs were randomized into active group (n=8) and control group (n=6). Porcine MSCs were transfected with Ad.HCN4 or Ad.Null. The pacemaker function of transfected MSCs was studied by whole-cell patch clamp. The CHB model of porcine was created with transthoracic ablation technique and the transfected MSCs were autografted into the free wall of right ventricle. The pacing function was studied by ECG and ambulatory Holter recording weekly. The adrenergic responsiveness was evaluated by the variation of heart rate after isoprenaline infusion or food provision following an overnight fasting. HCN4-MSCs expressed a robust time-dependent inward current (If) and the current density of If was 4.3±0.6 pA/pF at -105 mV. In week 2 after autograft, the heart rate of active group became significantly higher than control (53±5 bpm vs. 38±4 bpm, P<0.05) and the percent of pacing beats in active group was higher than control (69±10% vs. 28±8%, P<0.05). By infusion of isoprenaline, the heart rate was increased significantly in both groups. However, there was a significant increase of heart rate when presenting food for active group (P<0.05) while not in control., Conclusions: Our findings demonstrated that autografted HCN4-MSCs could increase the heart rate by providing an adrenergic-responsive biological pacing function, indicating a promising approach without immunological or ethical issues for the treatment of complete heart block., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

The objective of the study is to demonstrate a common etiology of hyperkalemia and illustrate a potential iatrogenic errors in treatment.

We present a rare case of a woman aged 62 years with refractory acute promyelocytic leukemia treated with arsenic trioxide leading to progressive, multilevel cardiac conduction block. After chelation treatment with dimercaprol, there was normalization of conduction., (Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Objective: The importance of maternal autoantibody levels in congenital heart block and elucidation of maternal factors that may reduce disease burden require further clarification., Study Design: Pregnancies complicated by maternal anti-Ro antibodies from 2007 through 2011 were retrospectively reviewed., Results: In all, 33 women were followed up throughout pregnancy. Semiquantitative maternal anti-La levels were significantly higher in pregnancies complicated by fetal heart block of any degree (median difference, 227.5; P = .04), but there was no difference in maternal anti-Ro levels. In all, 94% of fetuses maintained normal conduction when the mother was treated with hydroxychloroquine or daily prednisone therapy throughout pregnancy, compared to 59% in the untreated group (odds ratio, 0.1; P = .04)., Conclusion: Pregnancies complicated by fetal heart block did not have higher levels of maternal anti-Ro antibodies. Maternal anti-La level may be a useful predictor of fetal heart block. Maternal treatment with either hydroxychloroquine or daily low-dose prednisone throughout pregnancy may provide a protective effect., (Copyright © 2013 Mosby, Inc. All rights reserved.)

Introduction: Conduction block in the posterior right atrium (RA) plays an important role in perpetuating atrial flutter (AFL). Although conduction blocks have functional properties, it is not clear how the block line changes with the pacing rate, pacing site, and administration of antiarrhythmic drugs., Methods and Results: Forty patients with typical AFL were enrolled. Pacing (110, 170, 230 ppm) from the coronary sinus ostium (CSo) and low lateral RA was performed. After 1 mg/kg pilsicainide (pure sodium channel blockade) administration, the pacing protocol was repeated. Conduction block was assessed based on a color-coded isopotential map and 20 points of virtual unipolar electrograms in the posterior RA using noncontact mapping. Block line proportion was defined as the percentage of length of the block line between the superior and inferior vena cava. The pacing rate-dependent extension of the block proportion was significant during pacing from both sides (pacing from the CSo: 59 ± 17% at 110 ppm, 69 ± 16% at 230 ppm, P < 0.05; pacing from the low lateral RA: 43 ± 19% at 110 ppm, 55 ± 22% at 230 ppm, P < 0.05). The block line was significantly longer during CSo pacing than during low lateral RA pacing at each rate (all P < 0.05). After pilsicainide administration, the block line extended further., Conclusion: In addition to pacing rate-dependent and site-dependent changes in the block line, pilsicainide further extended the block line length. This phenomenon explains the clinical observation that counterclockwise AFL occurs more frequently than clockwise AFL, and the mechanism of class IC AFL., (© 2012 Wiley Periodicals, Inc.)

Interatrial block is an abnormally delayed atrial activation, characterized at ECG by prolonged P-wave duration (more than 110 ms), irrespective of morphology. We report the case of a patient with acute decompensated severe congestive heart failure, that at hospital admission showed a prolonged P-wave, which reverted after diuretic therapy. The dynamic change of the atrial P-wave correlates with clinical evolution and serum level modification of B-type natriuretic peptide.

Objective: Congenital heart block (CHB), a manifestation of neonatal lupus, is associated with maternal anti-Ro/SSA and anti-La/SSB autoantibodies and recurs in ∼18% of subsequent pregnancies. This study was undertaken to investigate the effect of the idiotype:antiidiotype (Id:anti-Id) antibody ratio in the ability of intravenous immunoglobulin (IVIG) administered during subsequent pregnancies to prevent CHB., Methods: We studied 16 anti-Ro/SSA and anti-La/SSB-positive pregnant women from the Preventive IVIG Therapy for Congenital Heart Block study who had previously given birth to a child with neonatal lupus. In 3 of the mothers, the study pregnancy resulted in the birth of a child with neonatal lupus (2 with CHB and 1 with rash). Sequential serum samples were obtained from all mothers immediately before the administration of IVIG during pregnancy and were evaluated for antibodies against the major B cell epitope 349-364aa of La/SSB (idiotype) and its antiidiotypic antibodies., Results: Following IVIG treatment, serum titers of anti-La(349-364) (Id antibodies) decreased in 80% of the mothers, and in 60% an increase in anti-Id antibodies against anti-La(349-364) was observed. The Id:anti-Id ratio was significantly higher in mothers whose offspring developed neonatal lupus compared to mothers who gave birth to a healthy child (P<0.0001). Removal of anti-Id antibodies substantially increased the reactivity against La(349-364) in sera from 5 of 7 mothers tested. All IVIG preparations were examined for Id and anti-Id antibody activity. IVIG from batches administered to mothers who gave birth to a healthy child had an Id:anti-Id activity ratio of <1, in contrast to that given to mothers who gave birth to a child with neonatal lupus. Addition of the IVIG preparations to the maternal sera further enhanced antiidiotypic activity (by up to 4.7-fold) in 11 of 13 patients studied., Conclusion: This is the first study in humans to demonstrate that IVIG influences the Id-anti-Id network of a specific pathogenic autoantibody. Specifically, we showed that IVIG enhanced the anti-Id antibody response in pregnant women with anti-La/SSB antibodies. A high Id:anti-Id ratio in both the IVIG preparation and the maternal serum may explain the absence of an effect of IVIG in preventing recurrent neonatal lupus in some cases., (Copyright © 2011 by the American College of Rheumatology.)

Background: Congenital heart block affects 2% of all mothers with anti-Ro/La antibodies, can cause heart failure in utero, and has a 20% mortality rate in the first 3 years of life. Maternal fluorinated steroids to prevent or reverse congenital heart block can cause pregnancy complications. Intravenous immunoglobulin (IVIG) has been given with maternal steroids to prevent the recurrence of congenital heart block, although its efficacy is unproven., Case: We report the use of IVIG to prevent progression of 2:1 congenital heart block with intermittent complete heart block. After two maternal infusions of IVIG (0.4 g/kg) at 31 weeks of gestation, the fetal heart rate reverted to long periods of sinus rhythm, which was sustained until postnatal life., Conclusion: Our case supports investigating IVIG in the prevention or treatment of this life-threatening condition.

Lyme Disease, caused by the spirochete Borrellia burgdorferi, is the most common vector-borne disease in the United States. Clinically, it primarily affects the skin, joints, nervous system, and heart. Lyme carditis occurs in 4%-10% of adults with Lyme disease. Transient variable-level atrioventricular blocks, occurring in 77% of adults with Lyme carditis, are the most common cardiac manifestation. Up to 50% of Lyme carditis patients may develop complete heart block. The incidence of Lyme carditis in the pediatric population is not well established. We present a pediatric patient with a transient asymptomatic complete heart block resulting from Lyme carditis, an under-recognized complication of Lyme disease in the pediatric population.

We present a case study of a patient with a congenital heart block associated with a left isomerism that was diagnosed during the 26th week of gestation. The mother had type 2 diabetes mellitus that was difficult to control during the early stages of the pregnancy. A fetal echocardiogram revealed an atrioventricular dissociation, with an atrial rate of 120 bpm and a ventricular rate of 55 bpm. Subsequent examinations also revealed a left isomerism in the fetus. To increase the fetal heart rate, a continuous intravenous infusion of ritodrine was administered. The fetal ventricular rate rapidly increased to 65 bpm. The pregnancy successfully continued until term and a female infant weighing 3,182 g was born via a cesarean section. A subsequent surgery was performed to provide the infant with a permanent cardiac pacemaker, and notably, the child is now 4 months of age and her growth has been within the normal range., (Copyright 2009 S. Karger AG, Basel.)

Purpose of Review: To describe the results of two recent prospective studies that may indicate how to monitor, diagnose, and treat fetuses with neonatal lupus manifesting with heart involvement and to summarize additional research reports regarding the pathophysiology and outcomes of this rare condition., Recent Findings: The PR Interval and Dexamethasone Evaluation study found 10 cases of neonatal lupus (10%) with three first-degree atrioventricular blocks (AVBs) and three complete heart blocks. The study included 98 pregnancies in 95 women with anti-SSA/Ro antibodies who completed weekly fetal Doppler echocardiogram-based evaluation. The authors concluded that they were unable to detect first-degree AVB before progression to complete heart block. A similar observational prospective study was performed in 70 fetuses of 56 mothers using tissue velocity fetal kinetocardiogram for measurement of PR prolongation. In this study, six fetuses (8.5%) showed first-degree AVB, and fast normalization of heart function was achieved through maternal treatment with fluorinated steroids. The authors concluded that fetal kinetocardiogram can detect first-degree AVB in the fetus exposed to maternal anti-SSA/Ro or anti-SSB/La antibodies or both and that fluorinated steroids given on detection were associated with normalized atrioventricular conduction in fetuses with first-degree AVB., Summary: Echo Doppler seems a less reliable method for early detection of fetus first-degree AVB, and it is suggested that fetal kinetocardiogram or fetal electrocardiography are preferred. Although atrioventricular block reverses spontaneously in some fetuses, parents and treating physicians should consider immediate treatment with fluorinated steroids once a first-degree AVB is detected due to the high risk of rapid progression to complete blockage.

This 63 years old man presented to the emergency room with chest pain of more than 12 hours duration. The initial electrocardiogram showed as ST segment elevation inferior and right ventricular infarction. He developed signs and symptoms consistent with cardiogenic shock, followed by life threatening ventricular fibrillation and cardiac arrest. After repeated cardio-respiratory resuscitations and successful cardiac defibrillation, thrombolytic therapy was administered followed by clinical and hemodynamic improvements. One-week later cardiac catheterization and coronary arteriography were performed. The study showed 93% obstructive lesion in the proximal right coronary artery, an angioplasty was performed and a stent was placed. After appropriate re-adjustment of medical therapy, the patient was discharged and followed in the outpatient clinic. Although the time frame to administer thrombolytic therapy was over the 12 hours window as suggested by the AHA guidelines1, the potential risks benefits in the casepresented justifed the used of fibrinolytic therapy. Considering the multiple complications that the patient presented, fibrinolytic therapy needs to be considered even after 12 hours of symptoms initiation, particularly when facilities for primary percutaneous coronary interventions are not readily available.

We evaluated the efficacy of dexamethasone (DEX) in anti-SSA/Ro-exposed fetuses newly diagnosed with congenital heart block. Previous use of DEX has been anecdotal with varying reports of therapeutic benefit. This was a multicenter, open-label, nonrandomized study involving 30 pregnancies treated with DEX (22 with third-degree block, 6 with second-degree block, 2 with first-degree block) and 10 untreated (9 with third-degree block, 1 with first-degree block). Initial median ventricular rates, age at diagnosis, and degree of cardiac dysfunction were similar between groups. Six deaths occurred in the DEX group. There was no reversal of third-degree block with therapy or spontaneously. In fetuses treated with DEX, 1/6 with second-degree block progressed to third-degree block and 3 remained in second-degree block (postnatally 1 paced, 2 progressed to third degree); 2 reverted to normal sinus rhythm (NSR; postnatally 1 progressed to second degree). DEX reversed the 2 fetuses with first-degree block to NSR by 7 days with no regression at discontinuation. Absent DEX, the 1 with first-degree block detected at 38 weeks had NSR at birth (overall stability or improvement in 4 of 8 in the DEX group vs 1 of 1 in the non-DEX group). Median gestational birth age was 37 weeks in the DEX group versus 38 weeks in the non-DEX group (p = 0.019). Prematurity and small size for gestational age were restricted to the DEX group. Pacemaker use and growth parameters at birth and 1 year were similar between groups. In conclusion, these data confirm the irreversibility of third-degree block and progression of second- to third-degree block despite DEX. A potential benefit of DEX in reversing first- or second-degree block was supported in rare cases but should be weighed against potential steroid side effects such as growth restriction.

Thrombectomy with the AngioJet rheolytic thrombectomy catheter frequently causes bradyarrhythmias. This necessitates temporary pacemaker insertion and limits the device's use. Novel approaches for treatment of bradyarrhythmias are being tested. This article focuses on the evidence supporting the role of adenosine in bradyarrhythmias during thrombectomy and presents; data from a porcine model and the first human experience supporting the use of aminophylline, a competitive inhibitor of the adenosine receptor, via an intracoronary route, for prevention of bradyarrhythmias during thrombectomy.

With advances in transcatheter treatment options, percutaneous device closure of ventricular septal defects has become a safe and practical alternative to surgical repair. While outcomes have been excellent, late complete heart bock has been documented during follow up of pediatric patients. We report a case of late complete heart block complicating percutaneous device closure of a ventricular septal defect in a 37-year-old female requiring permanent pacemaker insertion. The patient underwent transcatheter closure of an atrial and ventricular septal defect in the context of treated pulmonary hypertension and significant intracardiac shunting. Seven months after the procedure, the patient was admitted with presyncope, with electrocardiographic monitoring confirming complete heart block. While previously only reported in the pediatric literature, awareness of the possibility of complete heart block should be considered during the late follow up of adult patients.