Risk of cardiac conduction disorders, and pacemaker implantations among individuals tested for serum Borrelia burgdorferi antibodies, a nationwide, matched, population-based cohort study

OBJECTIVES

To investigate the short- and long-term risks of atrioventricular block and other cardiac conduction disorders associated with being tested for Borrelia burgdorferi (Bb) antibodies or Bb seropositivity as measures of confounding by indication and Bb infection, respectively.

METHODS

We performed a nationwide population-based matched cohort study (Denmark, 1993-2021). We included 52 200 Bb-seropositive individuals (stratified as only Bb-IgM-seropositive [n = 26 103], only Bb-IgG-seropositive [n = 18 698], and Bb-IgM-and-IgG-seropositive [n = 7399]) and two age- and sex-matched comparison cohorts: 104 400 Bb-seronegative individuals and 261 000 population controls. We investigated the risk associated with being tested for serum Bb antibodies and being Bb seropositive. Outcomes were atrioventricular block and other conduction disorders. We calculated short-term odds ratios (aOR) (within 1 month), and long-term hazard ratios (aHR) (after 1 month) adjusted for age, sex, diabetes, chronic heart failure, and kidney disease with 95% CI.

RESULTS

Compared with population controls, individuals tested for Bb antibodies had increased short- and long-term risks of atrioventricular block (aOR 47.9, 95% CI: 30.0-76.7, aHR 1.3, 95% CI:1.2-1.3), and other conduction disorders (aOR 18.2, 95% CI: 10.1-32.8, aHR 1.2, 95% CI: 1.1-1.4). Compared with Bb-seronegative individuals, only Bb-IgM-and-IgG-seropositive individuals had increased short-term risk of atrioventricular block (aOR: 2.1, 95% CI: 1.5-3.1).

DISCUSSION

The results suggest that Bb antibody testing is included in the diagnostic work-up of conduction disorders. Finally, that Bb seropositivity is not associated with other conduction disorders than atrioventricular block or with increased long-term risk of conduction disorders.

Incidence and prognosis of cardiac conduction system diseases in hypertension: the STEP trial

Patients with cardiac conduction system diseases (CSD) may have increased incidence and mortality of cardiovascular events. Here we report a post hoc analysis of the Strategy of Blood Pressure Intervention in the Elderly Hypertensive Patients (STEP) randomized clinical trial (ClinicalTrials.gov number, NCT03015311) concerning the effect of intensive blood pressure (BP) control on the incidence of new-onset CSD and the prognostic implications of preexisting or new-onset CSD. The incidence of new-onset CSD was similar in the intensive (n = 205, 6.42%) and standard (n = 188, 5.94%) treatment arms. Participants with preexisting CSD had a higher risk for acute decompensated heart failure. Increased age, male sex and increased body mass index were independently associated with increased risk for new-onset CSD. Our results suggest that intensive BP control may not reduce the incidence of new-onset CSD compared with standard BP control.

Incidence of carditis and predictors of pacemaker implantation in patients hospitalized with Lyme disease

BACKGROUND

Lyme carditis, defined as direct infection of cardiac tissue by Borrelia bacteria, affects up to 10% of patients with Lyme disease. The most frequently reported clinical manifestation of Lyme carditis is cardiac conduction system disease. The goal of this study was to identify the incidence and predictors of permanent pacemaker implantation in patients hospitalized with Lyme disease.

METHODS

A retrospective cohort analysis of the Nationwide Inpatient sample was performed to identify patients hospitalized with Lyme disease in the US between 2003 and 2014. Patients with Lyme carditis were defined as those hospitalized with Lyme disease who also had cardiac conduction disease, acute myocarditis, or acute pericarditis. Patients who already had pacemaker implants at the time of hospitalization (N = 310) were excluded from the Lyme carditis subgroup. The primary study outcome was permanent pacemaker implantation. Secondary outcomes included temporary cardiac pacing, permanent pacemaker implant, and in-hospital mortality.

RESULTS

Of the 96,140 patients hospitalized with Lyme disease during the study period, 10,465 (11%) presented with Lyme carditis. Cardiac conduction system disease was present in 9,729 (93%) of patients with Lyme carditis. Permanent pacemaker implantation was performed in 1,033 patients (1% of all Lyme hospitalizations and 11% of patients with Lyme carditis-associated conduction system disease). Predictors of permanent pacemaker implantation included older age (OR: 1.06 per 1 year; 95% CI:1.05-1.07; P<0.001), complete heart block (OR: 21.5; 95% CI: 12.9-35.7; P<0.001), and sinoatrial node dysfunction (OR: 16.8; 95% CI: 8.7-32.6; P<0.001). In-hospital mortality rate was higher in patients with Lyme carditis (1.5%) than in patients without Lyme carditis (0.5%).

CONCLUSIONS

Approximately 11% of patients hospitalized with Lyme disease present with carditis, primarily in the form of cardiac conduction system disease. In this 12-year study, 1% of all hospitalized patients and 11% of those with Lyme-associated cardiac conduction system disease underwent permanent pacemaker implantation.

A Novel Missense Mutation in TNNI3K Causes Recessively Inherited Cardiac Conduction Disease in a Consanguineous Pakistani Family

Cardiac conduction disease (CCD), which causes altered electrical impulse propagation in the heart, is a life-threatening condition with high morbidity and mortality. It exhibits genetic and clinical heterogeneity with diverse pathomechanisms, but in most cases, it disrupts the synchronous activity of impulse-generating nodes and impulse-conduction underlying the normal heartbeat. In this study, we investigated a consanguineous Pakistani family comprised of four patients with CCD. We applied whole exome sequencing (WES) and co-segregation analysis, which identified a novel homozygous missense mutation (c.1531T>C;(p.Ser511Pro)) in the highly conserved kinase domain of the cardiac troponin I-interacting kinase (TNNI3K) encoding gene. The behaviors of mutant and native TNNI3K were compared by performing all-atom long-term molecular dynamics simulations, which revealed changes at the protein surface and in the hydrogen bond network. Furthermore, intra and intermolecular interaction analyses revealed that p.Ser511Pro causes structural variation in the ATP-binding pocket and the homodimer interface. These findings suggest p.Ser511Pro to be a pathogenic variant. Our study provides insights into how the variant perturbs the TNNI3K structure-function relationship, leading to a disease state. This is the first report of a recessive mutation in TNNI3K and the first mutation in this gene identified in the Pakistani population.

Prevalence of Cardiac Arrhythmias and Distal Conduction Disorders in Patients With Chronic Chagas' Disease and Elevated Autoantibodies Against M2 Muscarinic Acetylcholine Receptors

Chagas' disease (ChD) is a parasitic disease endemic to regions of Latin America and with an increasingly global reach. Up to 30% of patients with ChD develop severe dilated cardiomyopathy, ventricular arrhythmias, conduction disorders and/or sudden cardiac death. Autoantibodies against M₂ muscarinic acetylcholine receptors (M₂ mAChR) have been implicated in the pathogenesis of ChD. We sought to understand whether there was an association between anti-M₂ mAChR autoantibody titers in patients with chronic ChD and the presence of distal cardiac conduction disorders or cardiac arrhythmias. We conducted a cross-sectional study in 79 patients from Argentina and Bolivia with chronic ChD without evident structural heart disease. Autoantibody titers were measured using indirect enzyme-linked immunosorbent assay. Elevated anti-M₂ mAChR autoantibody titers were associated with the presence of distal conduction disease but not with cardiac arrhythmias. High anti-M₂ mAChR autoantibody levels could assist with identifying early structural heart disease in patients with chronic ChD.

Balloon Filling Algorithm for Optimal Size of Balloon Expandable Prosthesis During Transcatheter Aortic Valve Replacement

Aim is to report on the results of an optimized balloon filling algorithm and suggest a refinement of the implantation approach to maximize safety. Appropriate sizing of balloon expandable valves during transcatheter aortic valve implantation is crucial. Study comprised 370 consecutive patients receiving SAPIEN 3 valve between 2015 and 2018. Valve expansion/recoil measurement in the inflow area, annular area, and outflow area was performed previously and postimplantation. Nominal balloon filling resulted in underexpansion-23 mm (20.96 mm), 26 mm (23.88 mm), and 29 mm (27.56 mm) SAPIEN 3 valves at the annular level. Increased balloon filling by 2 cc resulted in a gradual increase in valve diameter reaching 97.35% (23 mm), 96.50% (26 mm), and 96.11% (29 mm) of the nominal valve diameter. Final diameters were usually higher in the valvular inflow and outflow tracts. The 29 mm valve did not reach its nominal diameter with 2 cc overfilling and in none of inflow area (95.48%), annular area (96.11%), or outflow area (96.86%). Device success (by VARC II) was 96.2%. No root or septal rupture, device migration, mitral valve injury, coronary obstruction, or dissection occurred. Rate of new permanent pacemaker implantation was 8.3%. Paravalvular leakage was none or trace in most patients. Mean valve gradient was 10.77 mm Hg postprocedure. 1.9% of the patients had a maximum gradient of >40 mm Hg, 2.2% >20 mm Hg. In conclusion, an optimized balloon filling algorithm resulted in appropriate valve gradients, low levels of paravalvular leakage, low rates of permanent pacemaker implantation and no annular rupture.

One-Year Follow-Up of Conduction Abnormalities After Transcatheter Aortic Valve Implantation With the SAPIEN 3 Valve

Long-term evolution of new-onset conduction abnormalities and need of permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) have not been extensively evaluated. We describe the incidence and time course of new conduction abnormalities and the rate of PPI with the new-generation transcatheter aortic valve prosthesis Edwards SAPIEN 3 (S3). In total, 266 patients with severe aortic stenosis who underwent TAVI were retrospectively analyzed. Twelve-lead electrocardiograms at baseline, after TAVI, at discharge, at 1-, 6-, and 12-month follow-up were evaluated to identify conduction abnormalities and PPI requirements to investigate the correlates of PPI. After TAVI, a significant increase in PR interval duration and in QRS complex width was observed. New-onset left bundle branch block was observed in 65 patients (24%) after TAVI. The number of patients with left bundle branch block was maximum at hospital discharge and decreased at 12-month follow-up (39% and 32%, respectively). Thirty-five patients (13%) required PPI during the follow-up. However, paced rhythm was only observed in 7% of the patients with a complete 12-month follow-up. Patients who underwent PPI had a higher prevalence of first-degree atrioventricular block, complete right bundle branch block, and wider QRS complex at baseline. Baseline right bundle branch block and QRS width immediately after TAVI were the only variables independently associated with PPI. In conclusion, conduction disorders have a temporary nature after TAVI and showed a trend toward stabilization during the following months. With this new-generation device, the incidence of new conduction abnormalities requiring PPI is relatively low.

Cardiovascular diseases in Southern Tunisia: current trends and future projections

INTRODUCTION

Cardiovascular diseases (CVD) are a major cause of morbidity and mortality, driven by the epidemiological transition world-wide.

AIM

We aimed to describe the epidemiological profile of CVD hospitalizations, to assess their chronological trends and to estimate their future projected trends.

METHODS

We retrospectively collected data from the regional morbidity registry of the University Hospital of Sfax, Tunisia, between 2003 and 2016. We included patients with ischemic heart disease (IHD), heart failure (HF) and rhythm and conduction disorder (RCD).

RESULTS

The mean age-standardized hospital incidence rate (ASHIR) was 94.8, 20.6 and 14/100000 inhabitants/year for IHD, HF and RCD, respectively. Trends analysis of CVD showed a significant increase in the ASHIR of IHD from 54.3/100000 inhabitants in 2003 to 123/100000 inhabitants in 2016, with an Annual Percentage Change (APC) of 3.59% (95%CI:0.4-6.7%;p<0.001). An upward trend was observed for HF, with ASHIR rising from 8.6/100000 inhabitants in 2003 to 22.6/100000 inhabitants in 2016, with an APC of 8.29% (95%CI:4.1-12;p<0.001). For RCD, no significant change in ASHIR was found. Projections showed that the estimated ASHIR would attend 131 and 36.5/100000 inhabitants for IHD and HF, respectively, while RCD would decline to 19.6/100000 inhabitant in 2026.

CONCLUSIONS

IHD and HF were rising at an alarming rate and were expected to continue up to the next 10 years. Therefore, there is an urgent need to emphasize on primordial, primary, and secondary prevention in order to reduce the massive burden of CVD.

Relation of elevated serum uric acid levels to first-degree heart block and other cardiac conduction defects in hospitalized patients with type 2 diabetes

AIMS

Several studies have reported that moderately elevated serum uric acid levels are associated with an increased risk of tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus (T2DM). It is currently unknown whether an association also exists between elevated serum uric acid levels and cardiac conduction defects in patients with T2DM.

METHODS

We retrospectively analyzed a hospital-based sample of 967 patients with T2DM discharged from our Division of Endocrinology over the years 2007-2014. Standard electrocardiograms were performed on all patients and were interpreted by expert cardiologists.

RESULTS

Overall, 267 (27.6%) patients had some type of conduction defects on electrocardiograms (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block). Patients in the 3rd serum uric acid tertile had a higher prevalence of any cardiac conduction defects than those belonging to 2nd or 1st tertile, respectively (35.8% vs. 25.0% vs. 22.6%; p<0.0001). Elevated serum uric acid levels were associated with a nearly twofold increased risk of cardiac conduction defects after adjustment for age, sex, hemoglobin A1c, diabetes duration, metabolic syndrome, chronic kidney disease, chronic obstructive pulmonary disease, ischemic heart disease, valvular heart disease and medication use (adjusted-odds ratio 1.84, 95% confidence intervals 1.2-2.9; p=0.009).

CONCLUSIONS

Moderately elevated serum uric acid levels are associated with an increased prevalence of any cardiac conduction defects in hospitalized patients with T2DM, independent of multiple risk factors and potential confounding variables.