Optimized radiofrequency lesions through local impedance guidance for effective CTI ablation in right atrial flutter.

BACKGROUND: Although radiofrequency (RF) catheter ablation of cavo-tricuspid isthmus (CTI) is an established treatment for typical right atrial flutter (RAFL), it remains to be established whether local tissue impedance (LI) is able to predict effective CTI ablation and what LI drop values during ablation should be used to judge a lesion as effective. We aimed to investigate the ability of LI to predict ablation efficacy in patients with RAFL. METHODS: RF delivery was guided by the DirectSense™ algorithm. Successful single RF application was defined according to a defragmentation of atrial potentials (DAP), reduction of voltage (RedV) by at least 80% or changes on unipolar electrogram (UPC). The ablation endpoint was the creation of bidirectional conduction block (BDB) across the isthmus. RESULTS: 392 point-by-point RF applications were analyzed in 48 consecutive RAFL patients. The mean baseline LI was 105.4 ± 12Ω prior to ablation and 92.0 ± 11Ω after ablation (p < 0.0001). According to validation criteria, absolute drops in impedance were larger at successful ablation sites than at ineffective ablation sites (DAP: 17.8 ± 6Ω vs. 8.7 ± 4Ω; RedV: 17.2 ± 6Ω vs. 7.8 ± 5Ω; UPC: 19.6 ± 6Ω vs. 10.1 ± 5Ω, all p < 0.0001). LI drop values significantly increased according to the number of criteria satisfied (ranging from 7.5Ω to 19.9). BDB was obtained in all cases. No procedure-related adverse events were reported. CONCLUSIONS: A LI-guided approach to CTI ablation was safe and effective in treating RAFL. The magnitude of LI drop was associated with effective lesion formation and BDB and could be used as a marker of ablation efficacy. CLINICAL TRIAL REGISTRATION: Catheter Ablation of Arrhythmias with a High-Density Mapping System in Real-World Practice (CHARISMA). URL: http://clinicaltrials.gov/ Identifier: NCT03793998.

Conduction delay across the cavotricuspid isthmus block line caused by the gap near the inferior vena cava: the role of conduction block in the lower lateral right atrium.

The electrophysiological properties of the gap associated with the cavotricuspid isthmus (CTI) block line near the inferior vena cava (IVC) are not fully elucidated. Of 143 patients who underwent CTI block line ablation between September 2020 and April 2021, high-resolution CTI gap mapping was performed for 15 patients. Four patients were identified as having a gap near the IVC (IVC-side gap) despite wide double potentials (DPs) with > 90 ms intervals at the block line. Detailed gap mapping during coronary sinus ostial pacing was performed before and after touch-up ablation. CTI conduction delays caused by an IVC-side gap were classified into 3 patterns: (1) conduction delay at the IVC-side gap without detouring gap conduction, (2) detouring gap conduction due to intrinsic lower lateral right atrium (LLRA)-IVC functional block, and (3) detouring gap conduction due to LLRA-IVC conduction block created by lateral deviation of the CTI ablation line. In Pattern 2, IVC-side gap conduction traveled backward toward the crista terminalis below the LLRA-IVC junction and came back forward again above the border. One patient presented with a head-to-bottom activation pattern of the lateral right atrium (pseudo-CTI block). Pattern 3 was caused by lateral deviation of initial RF deliveries and presented with the same course as intrinsic LLRA-IVC functional block. All patients had wide DP intervals near the tricuspid annulus (mean, 112 ms) and just above the gap site (mean, 109 ms). An IVC-side gap associated with the CTI block line can present with various conduction delay patterns.

Histological finding of maternal antibody-associated congenital heart block accompanied by large atrial septal defect and severe cardiac dysfunction.

Cardiac dysfunction commonly occurs in congenital heart block associated with maternal anti-SSA antibodies, especially after pacemaker implantation. We report the case of a 4-year-old girl with antibody-associated congenital heart block and a large secundum atrial septal defect who presented with significant cardiac dysfunction 4 years after pacemaker implantation. Histological findings were useful for determining the course of treatment and perioperative risk of intracardiac repair.

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.

Neonatal lupus erythematosus - practical guidelines.

BACKGROUND: Neonatal lupus erythematosus is an autoimmune disease acquired during fetal life as a result of transplacental passage of maternal anti-Sjögren's-syndrome-related antigen A (anti-SSA/Ro), anti-Sjögren's-syndrome-related antigen B (anti-SSB/La) or anti-U1 ribonucleoprotein (anti-U1-RNP) antinuclear autoantibodies. CONTENTS: Clinical manifestations include skin lesions, congenital heart block, hepatobiliary involvement and cytopenias. Most of the disorders disappear spontaneously after clearance of maternal antibodies. Cardiac symptoms, however, are not self-resolving and often pacemaker implantation is required. Diagnosis is based on clinical presentation and the presence of typical antibodies in the mother's or infant's serum. OUTLOOK: Neonatal lupus erythematosus may develop in children born to anti-SSA/Ro or anti-SSB/La women with various systemic connective tissue diseases. However, in half of the cases, the mother is asymptomatic, which may delay the diagnosis and have negative impact on the child's prognosis. Testing for antinuclear antibodies should be considered in every pregnant woman since early treatment with hydroxychloroquine or intravenous immunoglobulin (IVIG) has proven to be effective in preventing congenital heart block.

Attenuating loss of cardiac conduction during no-flow ischemia through changes in perfusate sodium and calcium.

Myocardial ischemia leads to conduction slowing, cell-to-cell uncoupling, and arrhythmias. We previously demonstrated that varying perfusate sodium (Na+) and calcium (Ca2+) attenuates conduction slowing and arrhythmias during simulated ischemia with continuous perfusion. Cardioprotection was selectively associated with widening of the perinexus, a gap junction adjacent nanodomain important to ephaptic coupling. It is unknown whether perfusate composition affects the perinexus or ischemic conduction during nonsimulated ischemia, when coronary flow is reduced or halted. We hypothesized that altering preischemic perfusate composition could facilitate perinexal expansion and attenuate conduction slowing during global ischemia. To test this hypothesis, ex vivo guinea pig hearts (n = 49) were Langendorff perfused with 145 or 153 mM Na+ and 1.25 or 2.0 mM Ca2+ and optically mapped during 30 min of no-flow ischemia. Altering Na+ and Ca2+ did not substantially affect baseline conduction. Increasing Na+ and decreasing Ca2+ both lowered pacing thresholds, whereas increasing Ca2+ narrowed perinexal width (Wp). A least squares mean estimate revealed that reduced perfusate Na+ and Ca2+ resulted in the most severe conduction slowing during ischemia. Increasing Na+ alone modestly attenuated conduction slowing, yet significantly delayed the median time to conduction block (10 to 16 min). Increasing both Na+ and Ca2+ selectively widened Wp during ischemia (22.7 vs. 15.7 nm) and attenuated conduction slowing to the greatest extent. Neither repolarization nor levels of total or phosphorylated connexin43 correlated with conduction slowing or block. Thus, perfusate-dependent widening of the perinexus preserved ischemic conduction and may be an adaptive response to ischemic stress.NEW & NOTEWORTHY Conduction slowing during acute ischemia creates an arrhythmogenic substrate. We have shown that extracellular ionic concentrations can alter conduction by modulating ephaptic coupling. Here, we demonstrate increased extracellular sodium and calcium significantly attenuate conduction slowing during no-flow ischemia. This effect was associated with selective widening of the perinexus, an intercalated disc nanodomain and putative cardiac ephapse. These findings suggest that acute changes in ephaptic coupling may serve as an adaptive response to ischemic stress.

Intraprocedural high-degree atrioventricular block or complete heart block in transcatheter aortic valve replacement recipients with no prior intraventricular conduction disturbances.

BACKGROUND: Conduction disturbances are the most frequent complication of transcatheter aortic valve replacement (TAVR). However, no data exists regarding the outcomes of intraprocedural high-degree atrioventricular block (HAVB) or complete heart block (CHB) in patients without previous conduction disturbances. OBJECTIVES: The aim of this study was to evaluate the outcomes of intraprocedural-HAVB/CHB in patients without previous intraventricular conduction disturbances. METHODS: The occurrence of intraprocedural-HAVB/CHB was assessed in 676 consecutive patients undergoing TAVR, and two groups were established according to its duration: persistent-HAVB/CHB (PHAVB/CHB) and transient-HAVB/CHB (THAVB/CHB), not present at the end of the procedure. RESULTS: Intraprocedural-HAVB/CHB occurred in 50 patients (7.4%), being persistent in 32 (64.0%), and transient in 18 (36.0%). The use of Medtronic Corevalve Revalving System (MCRS) and a greater oversizing of the valve increased the risk of intraprocedural-HAVB/CHB (p < 0.001). Permanent pacemaker implantation (PPI) was more frequent in the PHAVB/CHB than in the THAVB/CHB group (96.9% vs. 33.3%; p < 0.001). At 1-month follow-up, the PHAVB/CHB group showed a 98% ventricular pacing rate (VPR) compared to 16% in the THAVB/CHB group (p < 0.001), and similar VPR were observed at 1-year follow-up (98% vs. 37%, p < 0.001). Left ventricular ejection fraction (LVEF) decreased at 1-year follow-up in patients with PHAVB/CHB (-3.9 ± 1.8%, p = 0.003). CONCLUSIONS: In TAVR recipients with no prior intraventricular conduction disturbances, intraprocedural-HAVB/CHB occurred in 7.4% of cases. HAVB/CHB was persistent in most cases and determined a high rate of PPI post-TAVR. Very high VPR at 1- and 12-month follow-up were observed, which in turn was associated with a negative effect on LVEF. These results support early PPI and close follow-up in patients developing intraprocedural-PHAVB/CHB.

Transcatheter Closure of Perimembranous Ventricular Septal Defects Using Different Generations of Amplatzer Devices: Multicenter Experience.

OBJECTIVES: To demonstrate safety and efficacy of using different generations of softer Amplatzer™ devices for ventricular septal defect (VSD) closure to avoid serious complications at follow-up. BACKGROUND: Transcatheter closure of perimembranous ventricular septal defects (PmVSD) is a well-established procedure; however, it is associated with unacceptable incidence of complete heart block. Great advantages have been achieved by using softer devices for VSD transcatheter closure. The first and second generation of Amplatzer™ occluders (AVP II, ADO, and ADO II) seem to offer a safe and attractive alternative for this procedure. These devices can be delivered using either an arterial (retrograde) or venous (prograde) approach. METHODS AND RESULTS: Patients with congenital PmVSD who underwent transcatheter closure using ADO, ADO II, and AVP II devices were included. Primary end point was to determine efficacy and safety of these generations of devices and to determine the incidence of complications at follow-up (complete AV block and aortic/tricuspid/mitral regurgitation). One hundred and nineteen patients underwent VSD closure at a median age of 5 years (8 months-54 years). During the catheterization, there were only minor complications and at follow-up of 36 ± 25.7 months (up to 99 months), the closure rate was high of 98.3% and freedom from AV block was 100%. CONCLUSIONS: The use of softer Amplatzer™ devices is a good alternative to achieve PmVSD closure safely with no risk of AVB during the procedure or at midterm follow-up.

Autoimmune congenital heart block and primary Sjögren's syndrome: characterisation and outcomes of 49 cases.

OBJECTIVES: To characterise autoimmune congenital heart block (CHB) associated with a maternal diagnosis of primary Sjögren's syndrome (pSS) confirmed either before, concomitant or after the first pregnancy complicated with CHB. METHODS: The following inclusion criteria were applied: (i) Mothers with positive Ro/La autoantibodies detected previously or at the time of diagnosis of the first case of CHB; (ii) diagnosis of CHB confirmed by fetal echocardiography; (iii) AV block diagnosed in uterus, at birth or within the neonatal period (0-27 days after birth) (8); (iv) absence of anatomical cardiac abnormalities which might be causal of AV block; and (v) maternal fulfillment of the 2002 SS criteria before, during or after having a pregnancy complicated with CHB. RESULTS: We identified 49 cases of autoimmune CHB in children born from 44 mothers who had a mean age at the time of pregnancy of 30.3 years (range 18 to 41). At the time of diagnosis of autoimmune CHB, all mothers had positive anti-Ro antibodies and 28/44 (64%) were positive for anti-La antibodies. Only 10 (22%) mothers with affected pregnancies had a diagnosis of primary SS at the time of diagnosis of the first pregnancy complicated by CHB (a mean of 4 years before, ranging from 1 to 10 years). In 6 (14%) mothers, primary SS was diagnosed during pregnancy or less than 12 months after the delivery/termination. In the remaining 28 (64%) mothers, pSS was confirmed 1-5 years after CHB diagnosis (n=19, 68%), 6-10 years after (n=2, 7%), or more than 10 years after the first case of CHB was diagnosed (n=7, 25%). CHB was diagnosed in uterus in all cases but two. AV block was initially incomplete in 11 fetuses and complete in 36 (no available data in 2 cases). Among the 35 (71%) surviving children with CHB, 5 (14%) developed other features of neonatal lupus. After the index pregnancy, 12 women had 20 subsequent pregnancies: five were complicated by a CHB (recurrence rate of CHB of 25%). The 4 women who had recurrent CHB were double-positive for anti-Ro and anti-La antibodies, and all had a confirmed pSS before having the first index case of CHB. CONCLUSIONS: In pSS, autoimmune CHB could be one of the first "indirect" signs of the disease in women of childbearing-age, in whom the diagnosis is confirmed several years later. Some maternal characteristics could be related with recurrent CHB, such as having an already-confirmed diagnosis of pSS and carrying the two Ro/La autoantibodies.

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

BACKGROUND: The incidence of Lyme disease (LD) in North America has increased substantially in the past two decades. Concomitant with the increased incidence of infection has been an enhancement in the recognition of LD complications. Here, we report a case of Lyme carditis complicated by heart block in a pediatric patient admitted to our children's hospital. What is unique about this case is that the complaint of chest palpitations is an infrequent presentation of LD, and what it adds to the scientific literature is an improved understanding of LD in the pediatric population. CASE PRESENTATION: The patient was a 16-year-old male who presented with the main concerns of acute onset of palpitations and chest pain. An important clinical finding was Erythema migrans (EM) on physical exam. The primary diagnoses were LD with associated Lyme carditis, based on the finding of 1st degree atrioventricular heart block (AVB) and positive IgM and IgG antibodies to Borrelia burgdorferi. Interventions included echocardiography, electrocardiography (EKG), and intravenous antibiotics. The hospital course was further remarkable for transition to 2nd degree heart block and transient episodes of complete heart block. A normal sinus rhythm and PR interval were restored after antibiotic therapy and the primary outcome was that of an uneventful recovery. CONCLUSIONS: Lyme carditis occurs in < 5% of LD cases, but the "take-away" lesson of this case is that carditis can be the presenting manifestation of B. burgdorferi infection in pediatric patients. Any patient with suspected Lyme carditis manifesting cardiac symptoms such as syncope, chest pain, or EKG changes should be admitted for parenteral antibiotic therapy and cardiac monitoring. The most common manifestation of Lyme carditis is AVB. AVB may manifest as first-degree block, or may present as high-grade second or third-degree block. Other manifestations of Lyme carditis may include myopericarditis, left ventricular dysfunction, and cardiomegaly. Resolution of carditis is typically achieved through antibiotic administration, although pacemaker placement should be considered if the PR interval fails to normalize or if higher degrees of heart block, with accompanying symptoms, are encountered. With the rising incidence of LD, providers must maintain a high level of suspicion in order to promptly diagnose and treat Lyme carditis.

Validation of scoring system predicting permanent pacemaker implantation after transcatheter aortic valve replacement.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) is being increasingly performed in patients with severe aortic stenosis. Despite newer generation valves, atrioventricular (AV) conduction disturbance is a common complication, necessitating permanent pacemaker (PPM) implantation in about 10% of patients. Hence, it is imperative to improve periprocedural risk stratification to predict PPM implantation after TAVR. The objective of this study was to externally validate a novel risk-stratification model derived from the National Inpatient Sample (NIS) database that predicts risk of PPM from TAVR. METHODS: Components of the score included pre-TAVR left and right bundle branch block, sinus bradycardia, second-degree AV block, and transfemoral approach. The scoring system was applied to 917 patients undergoing TAVR at our institution from November 2011 to February 2017. We assessed its predictive accuracy by looking at two components: discrimination using the C-statistic and calibration using the Hosmer-Lemeshow goodness of fit test. RESULTS: Ninety patients (9.8%) required PPM. The scoring system showed good discrimination with C-statistic score of 0.6743 (95% CI: 0.618-0.729). Higher scores suggested increased PPM risk, that is, 7.3% with score ⩽3, 19.23% with score 4-6, and 37.50% with score ≥7. Patients requiring PPM were older (81.4 versus 78.7 years, P = .002). Length of stay and in-hospital mortality was significantly higher in PPM group. CONCLUSIONS: The NIS database derived PPM risk prediction model was successfully validated in our database with acceptable discriminative and gradation capacity. It is a simple but valuable tool for patient counseling pre-TAVR and in identifying high-risk patients.

Risk factors for permanent pacemaker implantation in patients receiving a balloon-expandable transcatheter aortic valve prosthesis.

Permanent pacemaker implantation (PPI) is a widely recognized complication associated with TAVI (incidence up to 20%). Smaller registries have identified several variables associated with PPI. The objective was to validate patient- and transcatheter aortic valve implantation (TAVI)-related procedural variables associated with PPI. We performed a retrospective analysis of patients from six European centers undergoing TAVI with the Edwards SAPIEN 3 prosthesis. Baseline variables and pre-procedural ECG characteristics and CT-scans were taken into account. Data for 1745 patients were collected; 191 (10.9%) required PPI after TAVI. The baseline variables pulmonary hypertension (OR 1.64; 95% CI 1.01-2.59), QRS duration > 117 ms (OR 2.58; 95% CI 1.73-3.84), right bundle branch block (RBBB; OR 5.14; 95% CI 3.39-7.72), left anterior hemi block (OR 1.92; 95% CI 1.19-3.02) and first-degree atrioventricular block (AVB, OR 1.63; 95%CI 1.05-2.46) were significantly associated with PPI. RBBB (OR 8.11; 95% CI 3.19-21.86) and first-degree AVB (OR 2.39; 95% CI 1.18-4.66) remained significantly associated in a multivariate analysis. Procedure-related variables included access site (TF; OR 1.97; 95% CI 1.07-4.05), implanted valve size (29 mm; OR 1.88; 95% CI 1.35-2.59), mean TAVI valve implantation depth below the annulus > 30% (OR 3.75; 95% CI 2.01-6.98). Patients receiving PPI had longer ICU stays and later discharges. Acute kidney injury stage 2/3 was more common in patients with PPI until discharge (15.2 vs. 3.1%; p = 0.007), but was not statistically significant thereafter. Further differences in outcomes at 30 days did not reach significance. The data will aid pre- and post-procedural patient management and prevent adverse long-term outcomes.Clinical Trial: NCT03497611.

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.

Fulminant Myocarditis with Combination Immune Checkpoint Blockade.

Immune checkpoint inhibitors have improved clinical outcomes associated with numerous cancers, but high-grade, immune-related adverse events can occur, particularly with combination immunotherapy. We report the cases of two patients with melanoma in whom fatal myocarditis developed after treatment with ipilimumab and nivolumab. In both patients, there was development of myositis with rhabdomyolysis, early progressive and refractory cardiac electrical instability, and myocarditis with a robust presence of T-cell and macrophage infiltrates. Selective clonal T-cell populations infiltrating the myocardium were identical to those present in tumors and skeletal muscle. Pharmacovigilance studies show that myocarditis occurred in 0.27% of patients treated with a combination of ipilimumab and nivolumab, which suggests that our patients were having a rare, potentially fatal, T-cell-driven drug reaction. (Funded by Vanderbilt-Ingram Cancer Center Ambassadors and others.).

Permanent pacing and conduction recovery in patients undergoing cardiac surgery for active infective endocarditis in an Australian Tertiary Center.

BACKGROUND: Postoperative heart block is common among patients undergoing surgery for infective endocarditis (IE). Limited data exists allowing cardiologists to predict who will require permanent pacemaker (PPM) implantation postoperatively. We aimed to determine the rate of postoperative PPM insertion, predictors for postoperative PPM, and describe PPM utilization and rates of device-related infection during follow-up. MATERIALS AND METHODS: A retrospective analysis was performed of 191 consecutive patients from a single institution who underwent cardiac surgery for IE between 2001 and 2017. Preoperative and operative predictors for postoperative PPM were evaluated using univariate and multivariate logistic regression. RESULTS: The rate of postoperative PPM implantation was 11% (17/154). The PPM group had more preoperative prolonged PR interval alone (33% vs 12%; P = .03), coexistent prolonged PR and QRS durations (13% vs 2%; P = .01), infection beyond the valve leaflets (82% vs 41%; P = .001), aortic root debridement (65% vs 23%; P = <.001), patch repair (47% vs 20%; P = .01), postoperative prolonged PR interval (50% vs 24%; P = .01), and prolonged QRS duration (47% vs 15%; P = .001). On multivariate analysis, infection beyond the valve leaflets emerged as an independent predictor for postoperative PPM (odds ratio, 1.94, 95% confidence interval, 1.14-3.28; P = .014). A reduction in PPM utilization was observed in five patients while eight patients continued to show significant ventricular pacing with no underlying rhythm at 12 months. There were no device-related infections. CONCLUSION: Postoperative PPM was required in 11% of patients undergoing surgery for IE over a 16-year period. Infection beyond the valve leaflet was an independent predictor for postoperative PPM insertion.

Trends in complete heart block after transcatheter aortic valve replacement: A population based analysis.

OBJECTIVES: To define the national rate of complete heart block (CHB) after transcatheter aortic valve replacement (TAVR) and its impact on procedural mortality, overall cost, and length of hospital stay. BACKGROUND: CHB leading to permanent pacemaker (PPM) implantation is one of the most common complications post TAVR. National data on the temporal trend of CHB post TAVR are lacking. METHODS: We queried the 2012-2014 National Inpatient Sample databases to identify all patients who underwent TAVR. Patients with preoperative pacemakers or implantable cardioverter-defibrillators were excluded. Association between CHB and outcomes, and overall trends in rate of CHB, PPM implantation, and inpatient mortality were examined. RESULTS: Of 35,500 TAVR procedures, 3,675 (10.4%) had CHB. Overall, occurrence of CHB significantly increased from 8.4% in 2012 to 11.8% in 2014 (adjusted OR per year: 1.23; 95% confidence interval [CI]: 1.17-1.29, P trend <0.001). During the same period, PPM implantation increased from 9.5 to 13.7% (adjusted OR per year: 1.22; 95% CI: 1.16-1.28, P trend <0.001). Patients with CHB had higher odds of in-hospital mortality when compared to patients without CHB (5.9% vs. 4.2%, adjusted OR: 1.32; 95% CI: 1.12-1.56; p = 0.001). Moreover, CHB was also associated with longer length of stay (LOS) and higher hospitalization cost. CONCLUSIONS: There was a significant increase in rates of CHB and PPM implantation over the study period. Development of CHB was associated with increased in-hospital mortality, LOS, and hospitalization cost.

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

BACKGROUND: Lyme disease (LD), is the most common vector-borne illness in the US and Europe, with predominantly cutaneous, articular, cardiac and neuro-psychiatric manifestations. LD affects all layers of the heart and every part of the conducting system. Carditis is a less common manifestation of LD. Heart block (HB) as the initial and sole manifestation of LD is rare. Inducible HB has never been reported in LD. We report a case of heart block (HB) inducible with exercise and reversible with rest. CASE PRESENTATION: A 37-year-old male presented to the emergency department after experiencing two episodes of syncope while at work. He presented, with a heart rate of 57 bpm, and the ECG showed sinus bradycardia with first degree AV block. The PR interval was 480 ms (NL 120-200 ms). Physical exam was unremarkable. The cardiologist's initial impression was vaso-vagal attack. He developed high degree AV block during a stress test for the initial work up, which resolved on cessation of exercise. A similar episode while walking in the hallway, resolved at rest. The high degree AV block appeared inducible with exercise and reversible with rest. His Lyme serology was strongly positive. He was treated with ceftriaxone and doxycycline. After completing treatment, the patient had a normal ECG and returned to work without limitations, doing manual labor. CONCLUSIONS: Manifestations of Lyme carditis (LC) vary from asymptomatic and symptomatic electrocardiographic changes and heart block (HB) reversible with treatment, to sudden death. HB as the sole and initial presentation of LC is rare. There have been no reports of inducible HB in LD. Here we present a case of inducible and reversible high degree HB in a case of LC and an update of literature. Exercise and stress testing should be avoided in suspected cases of LC until resolution of carditis. Lyme carditis should be suspected in individuals with cardiac manifestations in an endemic area, particularly in the younger patients with no other etiology evident.

Cardiac conduction abnormalities associated with pacemaker implantation after transcatheter aortic valve replacement.

BACKGROUND: Complete heart block is a known complication after transcatheter aortic valve replacement (TAVR), often requiring pacemaker implantation within 24 hours of the procedure. However, clinical markers for delayed progression to complete heart block after TAVR remain unclear. OBJECTIVES: We examined electrocardiographic data that may correlate with delayed progression to complete heart block and need for pacemaker. METHODS: This is a single-center retrospective study of 608 patients who underwent TAVR between April 2008 and June 2017. We excluded 164 (27.0%) patients due to having a pacemaker before the procedure or expiring within 24 hours of the procedure (8, 1.3%). We excluded an additional 50 (8.2%) patients who received a pacemaker within 24 hours of the procedure. Electrocardiograms (EKGs) obtained after the procedure were compared to the preprocedural EKG to detect new changes. RESULTS: Left bundle branch block, intraventricular conduction delay, left anterior fascicular block, and right bundle branch block were the most commonly seen conduction abnormalities after TAVR (25.1%, 10.9%, 7.5%, and 3.6%, respectively). Both left bundle branch block (odds ratio [OR] = 2.77 [95% confidence interval (CI): 1.24-6.22]) and right bundle branch block (OR = 13.2 [95% CI: 4.18-41.70]) carried an increased risk of pacemaker implantation after TAVR. Additionally, ΔPR greater than 40 ms from baseline also carried an increased risk of pacemaker implantation (OR = 3.53 [95% CI: 1.49-8.37]). CONCLUSION: Left bundle branch block, right bundle branch block, and ΔPR greater than 40 ms were all associated with delayed progression to complete heart block and need for pacemaker implantation after TAVR.

A case of bidirectional conduction block within the superior vena cava induced by cryoballoon pulmonary vein isolation.

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.

Occurrence of complete heart block associated with acute renal infarction.

Complete heart block (CHB) and acute renal infarction (ARI) are both uncommon diseases and seldom encountered in the clinical practice. We describe a rare case of pre-existing left bundle branch block, presenting simultaneously with CHB and ARI. The possible mechanism depends on prior presence of either CHB or ARI. If ARI occurs first, severe pain and embolism may enhance the vagal tone resulting in decrease in the heart rate and transient intraventricular conduction interruption, which subsequently causes CHB. The opposite scenario, CHB preceding ARI, is also possible. CHB can be physiologic and transient, with higher risk of development in the circumstance of pre-existing conduction system disturbances. Patients with CHB are predisposed to formation of thrombi and thromboemboli, giving rise to ARI. In conclusion, awareness and timely identification of the clinical manifestations of these two diseases may facilitate early diagnosis and prompt management.