Cost of Pacing in Pediatric Patients With Postoperative Heart Block After Congenital Heart Surgery.

Importance: Surgical correction of congenital heart defects (CHDs) has improved the lifespan and quality of life of pediatric patients. The number of congenital heart surgeries (CHSs) in children has grown continuously since the 1960s. This growth has been accompanied by a rise in the incidence of postoperative heart block requiring permanent pacemaker (PPM) implantation. Objective: To assess the trends in permanent pacing after CHS and estimate the economic burden to patients and their families after PPM implantation. Design, Setting, and Participants: In this economic evaluation study, procedure- and diagnosis-specific codes within a single-institution database were used to identify patients with postoperative heart block after CHS between January 1, 1960, and December 31, 2018. Patients younger than 4 years with postoperative PPM implantation were selected, and up to 20-year follow-up data were used for cost analysis based on mean hospital event charges and length of stay (LOS) data. Data were analyzed from January 1, 2020, to November 30, 2022. Exposure: Implantation of PPM after CHS in pediatric patients. Main Outcomes and Measures: Annual trends in CHS and postoperative PPM implantations were assessed. Direct and indirect costs associated with managing conduction health for the 20 years after PPM implantation were estimated using Markov model simulation and patient follow-up data. Results: Of the 28 225 patients who underwent CHS, 968 (437 female [45.1%] and 531 male [54.9%]; 468 patients aged <4 years) received a PPM due to postoperative heart block. The rate of CHS and postoperative PPM implantations increased by 2.2% and 7.2% per year between 1960 and 2018, respectively. In pediatric patients younger than 4 years with PPM implantation, the mean (SD) 20-year estimated direct and indirect costs from Markov model simulations were $180 664 ($32 662) and $15 939 ($1916), respectively. Using follow-up data of selected patients with clinical courses involving 1 or more complication events, the mean (SD) direct and indirect costs were $472 774 ($212 095) and $36 429 ($16 706), respectively. Conclusions and Relevance: In this economic evaluation study, the cost of PPM implantation in pediatric patients was found to accumulate over the lifespan. This cost may represent not only a substantial financial burden but also a health care burden to patient families. Reducing the incidence of PPM implantation should be a focused goal of CHS.

Anti-SSA/Ro positivity and congenital heart block: obstetric and foetal outcome in a cohort of anti-SSA/Ro positive pregnant patients with and without autoimmune diseases.

OBJECTIVES: Neonatal lupus (NL) is an acquired disease caused by the transplacental passage of anti-SSA/Ro antibodies. The rate of congenital heart block (CHB), its most serious manifestation, ranges from 1 to 5%. The aim of this study was to retrospectively assess the prevalence of CHB in anti-SSA/Ro positive pregnant women with or without systemic autoimmune diseases from 2010 to 2020. METHODS: Patients underwent monthly visit and a shared follow-up programme of weekly (16th-24th week) foetal heart rate assessment by obstetric ultrasound. RESULTS: 322 pregnancies in 258 anti-SSA/Ro patients were included; 314 were followed from the beginning of pregnancy because of the known presence of anti-SSA/Ro autoantibodies and 1 case of CHB occurred in an anti-SSA/Ro+ asymptomatic subject (0.3%). In the same period, 8 additional patients were referred to our clinics after in utero CHB diagnosis and subsequent discovery of anti-SSA/Ro without a disease diagnosis. Globally, 9 cases of congenital CHB (2.8%) occurred: 7 complete, 1 II-III degree and 1 rst degree CHB. Anti-SSB/La positivity was associated with a higher risk of CHB (7.8% vs. 1.2%; p=0.0071). No differences in maternal or foetal outcomes were found in comparison with a large cohort of unselected pregnancies except for caesarian section. Hydroxychloroquine (HCQ) was used in 58.3% pregnancies, with a different prevalence according with maternal diagnosis. CONCLUSIONS: Our data suggest that anti-SSA/Ro positive patents with a de ned systemic autoimmune disease undergoing a strict follow-up since positive pregnancy test display a low risk of pregnancy complications, including but not limited to NL.

Cardiovascular Complications of Interatrial Conduction Block: JACC State-of-the-Art Review.

Interatrial block (IAB) is an electrocardiographic pattern describing the conduction delay between the right and left atria. IAB is classified into 3 degrees of block that correspond to decreasing conduction in the region of Bachmann's bundle. Although initially considered benign in nature, specific subsets of IAB have been associated with atrial arrhythmias, elevated thromboembolic stroke risk, cognitive impairment, and mortality. As the pathophysiologic relationships between IAB and stroke are reinforced, investigation has now turned to the potential benefit of early detection, atrial imaging, cardiovascular risk factor modification, antiarrhythmic pharmacotherapy, and stroke prevention with oral anticoagulation. This review provides a contemporary overview of the epidemiology, pathophysiology, diagnosis, and management of IAB, with a focus on future directions.

Outcomes After Transfemoral Transcatheter Aortic Valve Implantation With a SAPIEN 3 Valve in Patients With Cirrhosis of the Liver (a Tertiary Care Center Experience).

Little is known about the utility of transcatheter aortic valve implantation (TAVI) in patients with cirrhosis of the liver, and their outcomes have not been studied extensively in literature. We performed a retrospective analysis of patients with severe symptomatic aortic stenosis (AS) who underwent transfemoral TAVI with a SAPIEN 3 valve at our institution between April 2015 and December 2018. We identified 32 consecutive patients with evidence of cirrhosis of the liver on imaging (including ultrasound and/or computed tomography) and patients with severe symptomatic AS who underwent transfemoral TAVI with a SAPIEN 3 valve. Among 1,028 patients, 32 had cirrhosis of the liver and 996 constituted the control group without cirrhosis. Mean age in the cirrhosis group was 74.5 years compared with 81.2 years in the control group. Baseline variables were comparable between the groups. Compared with the noncirrhotic group, patients with cirrhosis had a similar 1-year mortality (12% vs 12%, p = 1), a lower 30-day new pacemaker after TAVI rate (6% vs 9%, p = 0.85), a higher 30-day and 1-year readmission rate for heart failure (11% vs 1% and 12% vs 5%, p = 0.12, respectively), and a similar 1-year major adverse cardiac and cerebrovascular event rate (15% vs 14%, p = 0.98). In conclusion, patients with severe AS with concomitant liver cirrhosis who underwent TAVI demonstrated comparable outcomes to their noncirrhotic counterparts.

Usefulness of Left Ventricular Myocardial Deformation in Children Hospitalized for Acute Myocarditis who Develop Arrhythmias.

Cardiac arrhythmias occur in 3-40% of patients with acute myocarditis and cause significant morbidity and mortality. Myocardial injury also results in abnormal myocardial deformation. The relationship between left ventricular (LV) deformation, measured by two-dimensional speckle tracking echocardiography (2D-STE), and arrhythmia in pediatric myocarditis is unknown. We evaluated the association between 2D-STE and arrhythmias in children hospitalized with acute myocarditis. We reviewed patients ≤ 18 years hospitalized for acute myocarditis from 2008 to 2018. Arrhythmias were defined as 1) non-sustained or sustained ventricular tachycardia or ventricular fibrillation, 2) sustained supraventricular tachycardia (SVT), 3) high-grade or complete heart block, and 4) any arrhythmia treated with an antiarrhythmic medication. Systolic LV strain values (including LV global longitudinal strain (GLS), global circumferential strain (GCS), and six segments of LV regional long axis strain) were obtained from initial echocardiograms during hospitalization. Of 66 patients hospitalized, 23 (35%) had arrhythmias. SVT was the predominant arrhythmia (74%). Global and regional strain indices were reduced in the arrhythmia group: LV GLS [-8.9 (IQR -13.6, -6.1) vs. -13.7 (IQR -16.9, -9.7), p = 0.038]; basal inferior/septal [-10.7 (IQR -15.5, -7.8) vs. -16.4 (IQR -18, -11.8), p = 0.009]; basal anterior/lateral [-7.1 (IQR -12.8, -4.7) vs. -9.4 (IQR -16.7, -7.4), p = 0.025]; and mid inferior/septal segments [-9 (IQR -13, -7.7) vs. -14.1 (IQR -22.5, -10.7), p = 0.007]. After controlling for age, reductions in GLS and segmental strain in the two basal and two mid-segments were associated with increased arrhythmia occurrence (p <0.05). Our findings suggest that echocardiographic LV deformation by 2D-STE may be useful in identifying pediatric patients with acute myocarditis at risk for arrhythmias.

Interferons and innate immune activation in autoimmune congenital heart block.

Autoimmune congenital heart block (CHB) may develop in foetuses of women carrying anti-Ro/SSA and La/SSB autoantibodies and is characterized by disruption of signal conduction at the atrioventricular (AV) node, resulting in partial or complete AV block. If not fatal in utero, complete CHB typically requires lifelong cardiac pacing. No treatment has so far been unequivocally demonstrated to prevent or treat autoimmune CHB, and the relatively low incidence (1%-5%) and recurrence (12%-16%) rates of second/third-degree AV block add to the complexity of managing pregnancies in women with anti-Ro/La antibodies. Altogether, a better understanding of events leading to development of autoimmune CHB is needed to improve surveillance and treatment strategies. In the past decade, studies have started to look beyond the role of maternal autoantibodies in disease pathogenesis to assess other contributing factors such as foetal genetics and, more recently, immune responses in foetuses and neonates of anti-Ro/La antibody-positive women. In this review, we provide an update on the epidemiology, clinical presentation and current treatment approaches of autoimmune CHB, summarize the previously proposed pathogenic mechanisms implicating maternal autoantibodies, and discuss the recent findings of type I interferon (IFN) and innate immune activation in foetuses with autoimmune CHB and in neonates of anti-Ro/La antibody-positive mothers, and how these may contribute to autoimmune CHB pathogenesis.

Impact of Arrhythmias on Hospitalizations in Patients With Cardiac Amyloidosis.

Cardiac involvement in amyloidosis is associated with a poor prognosis. Data on the burden of arrhythmias in patients with cardiac amyloidosis (CA) during hospitalization are lacking. We identified the burden of arrhythmias using the National Inpatient Sample (NIS) database from January 2016 to December 2017. We compared patient characteristics, outcomes, and hospitalization costs between CA patients with and without documented arrhythmias. Out of 5,585 hospital admissions for CA, 2,020 (36.1%) had concurrent arrhythmias. Propensity-score matching for age, sex, income, and co-morbidities was performed with 1,405 CA patients with arrhythmias and 1,405 patients without. The primary outcome of all-cause mortality was significantly higher in CA patients with arrhythmia than without(13.9% vs 5.3%, p-value <0.001). Atrial fibrillation (AF) was the most common (72.2%) arrhythmia in CA patients with concurrent arrhythmia. The secondary outcomes of AF-related mortality (11.95% vs 9.16%, p-value = 0.02) and acute and acute on chronic as heart failure (HF) exacerbation (32.38% vs 24.91%, p-value <0.0001) were significantly higher in CA and concurrent arrhythmia compared with CA patients without. The total length of hospital stay (6[3 to 12] vs 5[3 to 10], p-value <0.001) and cost of hospitalization were ($ 15,086[7,813 to 30,373] vs $ 12,219[6,865 to 23,997], p-value = 0.001) were significantly greater among CA with arrhythmia compared with those without. These data suggest that the presence of arrhythmias in CA patients during hospital admission is associated with a poorer prognosis and may reflect patients with a higher risk of HF exacerbation and mortality.

Short term clinical outcomes and analysis of risk factors for pacemaker implantation: a single center experience of self-expandable TAVI valves.

OBJECTIVES: Transcatheter aortic valve implantation is a recognized treatment for patients with severe aortic stenosis at all risk groups. However, permanent pacemaker rates remain high for self expandable transcatheter valves and permanent pacemaker implantation has been associated with increased morbidity. In this analysis we aim to evaluate short term clinical outcomes post self expandable transcatheter aortic valve implantation and determine risk factors for permanent pacemaker implantation. METHODS: 88 patients with severe aortic stenosis with transcatheter aortic valve implantation performed between the year 2016-2018 were retrospectively analyzed. Outcomes of interest included 1- year all cause mortality, 30-day major adverse cardiovascular events, permanent pacemaker and paravalvular leak rates. Survival analysis was performed with Kaplan Meier analysis and risk factors for survival and permanent pacemaker rates were identified with log rank test and regression analysis. RESULTS: The mean age of the cohort was 80.3 +/- 6.9 years. The mean STS score was 9.25. The 30 day all-cause mortality was 5.7% and 1-year all cause mortality was 16.7%. 80 patients had transfemoral transcatheter aortic valve implantation, and a majority of the patients (85.2%) were implanted with Corevalve Evolut R device. The device success rate was 88.6%. Multivariate analysis identified concomitant severe coronary artery disease (OR = 18.2 +/- 0.9; P = 0.002), pre transcatheter aortic valve implantation atrial fibrillation (OR = 8.6 +/- 0.91; P = 0.02) and post procedural disabling stroke (OR = 32.6 +/- 1.35; P = 0.01) as risk factors for 1-year mortality. The 30-day pacemaker rate was 17.6%. The presence of right bundle branch block (OR 11.1 +/- 0.86; P = 0.005), non-coronary cusp implantation depth (OR = 1.34 +/- 0.15; P = 0.05) and a non coronary cusp implantation depth / membranous septal length ratio of more than 50% were associated with post procedural pacemaker implantation (OR = 29.9 +/- 1.72; P = 0.05). Among the 15 patients with post procedural pacemaker implantation, 40% were found to be non-pacemaker dependent at 1 year. CONCLUSION: Short term outcomes of transcatheter aortic valve implantation in severe aortic stenosis patients are promising. Pacemaker rates remain high. More studies are needed to evaluate the factors that influence pacemaker rates and dependence to further improve transcatheter aortic valve implantation outcomes.

Heterogeneity in Conduction Underlies Obesity-Related Atrial Fibrillation Vulnerability.

BACKGROUND: Obese patients are more vulnerable to development of atrial fibrillation but pathophysiology underlying this relation is only partly understood. The aim of this study is to compare the severity and extensiveness of conduction disorders between obese patients and nonobese patients measured at a high-resolution scale. METHODS: Patients (N=212) undergoing cardiac surgery (male:161, 63±11 years) underwent epicardial mapping of the right atrium, Bachmann bundle, and left atrium during sinus rhythm. Conduction delay (CD) was defined as interelectrode conduction time of 7 to 11 ms and conduction block (CB) as conduction time ≥12 ms. Prevalence of CD/CB, continuous CDCB (cCDCB), length of CD/CB/cCDCB lines, and severity of CB were analyzed. RESULTS: In obese patients, the overall incidence of CD (3.1% versus 2.6%; P=0.002), CB (1.8% versus 1.2%; P<0.001), and cCDCB (2.6% versus 1.9%; P<0.001) was higher and CD (P=0.012) and cCDCB (P<0.001) lines are longer. There were more conduction disorders at Bachmann bundle and this area has a higher incidence of CD (4.4% versus 3.3%, P=0.002), CB (3.1% versus 1.6%, P<0.001), cCDCB (4.6% versus 2.7%, P<0.001) and longer CD (P<0.001) or cCDCB (P=0.017) lines. The severity of CB is also higher, particularly in the Bachmann bundle (P=0.008) and pulmonary vein (P=0.020) areas. In addition, obese patients have a higher incidence of early de-novo postoperative atrial fibrillation (P=0.003). Body mass index (P=0.037) and the overall amount of CB (P=0.012) were independent predictors for incidence of early postoperative atrial fibrillation. CONCLUSIONS: Compared with nonobese patients, obese patients have higher incidences of conduction disorders, which are also more extensive and more severe. These differences in heterogeneity in conduction are already present during sinus rhythm and may explain the higher vulnerability to atrial fibrillation of obese patients.

Arrhythmias in Relation to Mortality After Transcatheter Aortic Valve Replacement.

BACKGROUND: The purpose of this study was to identify predictors of mortality and potentially modifiable factors related to arrhythmias in patients that undergo transcatheter aortic valve replacement (TAVR). Patients that undergo TAVR are at risk for complete heart block requiring pacemaker implant. Additionally, other arrhythmias, specifically atrial fibrillation (AF), are common in this population. It is unclear how arrhythmias and their management contribute to mortality risk. METHODS: The study analyzed 176 patients who underwent TAVR at a single center. Factors associated with pacemaker implantation within 30 days were analyzed by logistic regression. Factors associated with mortality were analyzed by Kaplan-Meier and Cox regression analyses. RESULTS: Mean age was 80 ± 8.5 years. AF was present in 69 patients, and 39 received anticoagulation. Post-TAVR, a pacemaker was implanted in 25 patients within 30 days. Over a follow up of 566 ± 496 days, 49 patients died. In multivariable analysis, right bundle branch block remained significant (odds ratio 4.212, P = 0.012) for pacemaker implant within 30 days. The AF (hazard ratio [HR] 3.905, P = 0.001), albumin level (HR 0.316, P = 0.034), and diabetes (HR 2.323, P = 0.027) were predictors of death in a multivariate analysis, while pacemaker implant within 30 days was not. Patients with AF who were anticoagulated had improved survival in a stratified Kaplan-Meier analysis compared with those who were not anticoagulated (P = 0.0001). CONCLUSION: AF, diabetes, and low albumin levels are independently associated with mortality after TAVR. In particular, patients with AF who are not anticoagulated are at highest risk for death. Efforts to identify AF and consider anticoagulation should be emphasized.

Temporal Occurrence of Arrhythmic Complications After Alcohol Septal Ablation.

BACKGROUND: The temporal occurrence of arrhythmic complications after alcohol septal ablation (ASA) is unclear. As a result, the appropriate time to monitor patients after ASA is controversial. The purpose of this study is to determine the temporal occurrence of complete heart block (CHB) and ventricular tachyarrhythmia (VT) after ASA to better understand when patients can be safely discharged. METHODS: Consecutive patients treated with ASA for hypertrophic cardiomyopathy from 2003 to 2019 at a tertiary referral center were reviewed retrospectively. The incidence and timing of CHB or sustained VT within 30 days post-ASA were assessed. RESULTS: A total of 243 patients were included in this study. Mean maximal septal thickness was 19.0±3.9 mm, and total volume of ethanol injected was 1.7±0.6 mL. CHB occurred in 59 (24.3%) patients, including transient CHB in 33 (13.6%) and permanent in 26 (10.7%). The initial episode of CHB occurred within 24 hours post-ASA in 51 (21.0%) patients, between 24 and 48 hours in 3 (1.2%), between 48 and 72 hours in 3 (1.2%), and after 72 hours in 2 (0.8%). New permanent pacemaker was placed in 46 (18.3%). Presence of baseline bundle branch block and age ≥70 were significantly associated with CHB but not CHB presenting after 24 hours. VT occurred in 3 (1.2%) patients, including 1 (0.4%) within 24 hours, 1 (0.4%) between 24 and 48 hours, and 1 (0.4%) after 72 hours. VT required cardioversion in 2 patients and new implantable cardioverter-defibrillator placement in 2. CONCLUSIONS: The incidence of CHB or VT presenting after 72 hours post-ASA was low. These findings suggest that timely discharge of patients without evidence of early conduction disturbances after ASA can be considered as a potentially safe management strategy, especially in patients without preexisting conduction abnormalities.

Geoepidemiology and clinical characteristics of neonatal lupus erythematosus: a systematic literature review of individual patients' data

Background/aim: Neonatal lupus erythematosus (NLE) is an autoimmune syndrome caused by transplacental transmission of maternal autoantibodies, often with devastating consequences. The objective of this systematic literature review was to analyze the demographic data, geoepidemiology, clinical, and serological characteristics associated with NLE. Materials and methods: We performed a systematic literature search of the Pubmed database covering the period from 1976 to August 2015, using the MeSH terms "neonatal lupus" or "congenital heart block". To be included in the study, articles of any type (original articles, case series, and case reports) had to report on infants with NLE on an individualized (i.e. patient-by-patient) basis. Results: A total of198 studies were included in the review, reporting on a total of 755 NLE patients. The most frequently reported clinical manifestations of NLE were congenital heart block (CHB, 65.2%), cutaneous lupus (33.1%), and cytopenias (15.5%). We found differences in NLE characteristics based on study geographical origin, with CHB being much more frequent in patients of European or American descent (49.4% and 35%, respectively), while reports originating from Asia reported a higher prevalence of skin involvement (45.2%). Most CHB cases (72.9%) were diagnosed between the 18th and 26th week of gestation. Conclusions: Phenotypic differences of NLE depending on race and country may reflect true pathophysiologic differences or methodologic discrepancies. While maternal autoimmune disease is not a prerequisite for the development of NLE, the existence of a truly "immunonegative" CHB is questionable.

Transcatheter Aortic Valve Replacement in Patients With Symptomatic Severe Aortic Stenosis and Prior External Chest Radiation.

BACKGROUND/PURPOSE: Surgical aortic valve replacement (SAVR) in patients with symptomatic severe aortic stenosis (AS) and prior chest radiation is associated with poor outcomes in comparison with patients without prior radiation. Our objective was to compare clinical outcomes of patients with and without prior chest radiation undergoing transcatheter aortic valve replacement (TAVR) for symptomatic severe AS. METHODS/MATERIALS: Between January 2003 and January 2017, 1150 patients underwent TAVR at our institution. Of these, 44 had prior chest radiation. Baseline demographic and clinical characteristics, procedural details, and clinical outcomes were prospectively collected. RESULTS: Patients with prior chest radiation were younger, 76 ±â€¯13 years, compared with those without prior chest radiation, 82 ±â€¯8 years (p = 0.002). Median Society of Thoracic Surgeons score for chest radiation patients was 7 ±â€¯4, compared to 8 ±â€¯5 in those without prior radiation. Despite higher prevalence of complete heart block, there was no significant difference between the 2 groups with regard to the need for permanent pacemaker implantation. There was a trend toward longer length of intensive care unit stay in chest radiation patients, but there was no significant difference in 30-day or 1-year mortality. CONCLUSIONS: Thus, TAVR appears to be a safe treatment option in the short and medium term for patients with symptomatic severe AS and prior chest radiation.

Hypertensive Retinopathy: A Prognostic Factor for Morbidity and Mortality after Acute ST Elevation Myocardial Infarction.

OBJECTIVE: To determine the association between hypertensive retinopathy (HR) and post ST elevation myocardial infarction (STEMI) complications among successfully thrombolysed patients. STUDY DESIGN: A cohort study. PLACE AND DURATION OF STUDY: Cardiology Unit, Lady Reading Hospital, Peshawar, from June 2016 to December 2017. METHODOLOGY: Patients with history of hypertension for at least 5 years who presented with STEMI and were successfully thrombolysed, were included. On the basis of fundoscopy, patients were grouped into no, mild, moderate, and severe hypertensive retinopathy. Primary and secondary endpoints included a composite of death, re-MI, stroke, re-hospitalisation secondary to left ventricular failure, cardiogenic shock, arrhythmia, heart block, and ventricular septal rupture at 30 days and 4 months, respectively. Association between hypertensive retinopathy and post STEMI complications was determined by Chi-square test. Regression model was used to calculate relative risk of complications with hypertensive retinopathy. P <0.05 was taken as significant. RESULTS: A total of 118 patients with a mean age of 54.83 ±8.6 years were included in the study. Of these, 49.2% (n=58) were males. Moreover, 38.1% (n=45) of patients were grouped under no HR, 22.8% (n=27) under mild HR, 21.1% (n=25) and 17.7% (n=21) under moderate and severe HR, respectively. Primary endpoints achieved were 0% in no HR group and 19% in severe HR group x² = 18.1, p <0.001). Secondary endpoints were achieved in 2.2% in no HR group and 40.7%, 56% and 100% in mild, moderate and severe HR group, respectively, ( x² = 81.1, p <0.001). HR also increased the relative risk of complications by 3.17 times (p <0.001) and death by 1.75 times (p <0.001). CONCLUSION: Hypertensive retinopathy is an independent risk factor for post-acute STEMI complications in successfully thrombolysed patients and increased the relative risk for complications by 3.17 times.

Transcatheter aortic valve replacement and cardiac conduction.

INTRODUCTION: Conduction abnormalities after transcatheter aortic valve replacement (TAVR) account for a high percentage of post-TAVR complications. Areas covered: The etiology of conduction abnormalities is closely tied to cardiac anatomy (length of membranous septum, degree of calcification, location of left bundle within the membranous septum), baseline conduction abnormalities (preprocedure right bundle branch block), and procedural variables (type of valve, depth of implant). Management of new high-grade AV block and new left bundle branch block varies by institution in the absence of consensus guidelines. Expert opinion: Authors describe the incidence, etiology, outcomes, and management of conduction abnormalities related to aortic stenosis and TAVR.

Outcomes of Heart Block in Myocarditis: A Review of 31,760 Patients.

BACKGROUND: Various electrocardiographic abnormalities, including atrioventricular conduction block, have been reported in patients with myocarditis. We performed an observation study to describe the characteristics and outcomes of inpatients diagnosed with myocarditis complicated by heart block (HB) in a large national cohort. METHODS: We identified patients with primary ICD-9 codes for myocarditis HB from the Nationwide Inpatient Sample (NIS) Database from 1998 to 2013. We compared the baseline characteristics and compared clinical outcomes between patients with and without HB, and in patients with/without high degree atrioventricular block (HDAVB). RESULTS: From the NIS database, 31,760 patients had a principal diagnosis of myocarditis and HB was reported in 1.7% of these patients (n=540). Female gender and Asian race were independently associated with HB. Out of 540 patients, 363 patients had HDAVB (67.2%) and 177 patients had not advanced HB (32.8%). Not advanced HB was not associated with an increased mortality rate compared to patients without HB (0% vs. 2.7%, p=0.315). On the other hand, the incidence of cardiogenic shock, respiratory failure and renal failure were higher in patients with HDAVB (26.2% vs. 5.0%, 33.9% vs. 5.9% and 29.2% vs. 5.5%, p<0.001 respectively). Patients with HDAVB required more procedural support (incidence of intra-aortic balloon pump 17.8% vs. 3.3%). They also had significantly longer lengths of hospital stay (9.4±9.4 vs. 4.3±8.4, p<0.001) and higher mortality (15.5% vs. 2.7%, p<0.001). Compared to myocarditis patients without HB, the odds for mortality in myocarditis patients with HDAVB 1.58 (95% CI=1.03-2.49, p=0.039). CONCLUSIONS: The incidence of HB and HDAVB among patients with acute myocarditis was 1.7% and 1.1% respectively. Female gender and Asian race were both independently associated with significant odds for the occurrence of HB and HDAVB. High degree atrioventricular block was independently associated with increased morbidity and mortality.