Incidence of dementia in relation to genetic variants at PITX2, ZFHX3, and ApoE ε4 in atrial fibrillation patients

INTRODUCTION

Mechanisms underlying atrial fibrillation (AF) and dementia are unknown. Some genetic risk factors convey risk for AF and cerebral ischemic events. These markers may identify AF patients at risk for dementia either directly or through a gene-gene interaction with the ApoE ε4 variant, a known marker of dementia risk.

METHODS

Caucasian patients with AF and a subsequent dementia diagnosis (n = 112) were matched 1:2 on sex, AF onset age, and follow-up period to AF patients without dementia. AF patients with dementia and AF patients without dementia were matched 1:1 on sex and age at dementia diagnosis (n = 112). Genotyping employed Taqman real-time polymerase chain reaction. Multivariable conditional logistic regression was used to examine associations between AF/dementia groups and single nucleotide polymorphism (SNP), as well as gene-gene interactions.

RESULTS

In dementia patients, there was an association between the PITX2 loci and AF (rs2634073: odds ratio [OR] = 2.11; P = 0.025 and rs2200733: OR = 2.27; P = 0.029). In patients with AF, there was an association between PITX2 loci, rs2200733, and dementia (OR = 2.15, P = 0.008). There was no association between ApoE ε4 allele and AF in patients with dementia, although confirmation of the association between the carriage of ApoE ε4 allele and dementia was found (OR = 1.79; P = 0.026) in patients with AF. There were no significant interactions between ApoE ε4 allele and both the PITX2 loci and ZFHX3.

CONCLUSIONS

These findings support prior studies of ApoE risk of noncerebral vascular accident-related dementia/Alzheimer's risk in the Caucasians and provide support to suggest an association between PITX2-related SNPs and dementia, which may in part be attributed to silent cerebral ischemic events, a hypothesis deserving further testing.

Nonsustained ventricular tachycardia in heart failure with preserved ejection fraction

BACKGROUND

Ventricular tachycardia (VT) is a common arrhythmia in heart failure with reduced ejection fraction but its incidence, predictors, and significance have not been determined in heart failure with preserved ejection fraction (HFpEF).

METHODS

We performed a retrospective review of arrhythmias in two cohorts of patients with an HFpEF diagnosis. Patients in cohort 1 (n = 40) underwent routine arrhythmia surveillance with a 14-day ambulatory electrocardiogram (ECG) monitor. Patients in cohort 2 (n = 85) had cardiac pacemakers and underwent routine device interrogations.

RESULTS

In cohort 1, 13 patients (32.5%) had one or more episodes of nonsustained VT (NSVT) on ambulatory ECG. In cohort 2, 38 patients (44.7%) had NSVT on cardiac pacemaker interrogations. During a median (interquartile range) follow-up of 3.0 (1.6 to 5.1) years, 15 (12%) patients died (20% of patients with NSVT versus 6.8% of those without NSVT; P = .03). In logistic regression analysis, NSVT was associated with a 3.4-fold higher odds of death (95% confidence interval 1.08 to 10.53; P = .04) in HFpEF.

CONCLUSIONS

In conclusion, patients with HFpEF have a relatively high, and possibly underappreciated, burden of NSVT, which confers a higher risk of mortality. The frequent episodes of NSVT in these patients may provide insight into the mechanism of sudden cardiac death in HFpEF.

Ventricular arrhythmias involving the His-Purkinje system in the structurally abnormal heart

His-Purkinje-related ventricular arrhythmias are a subset of ventricular tachycardias that use the specialized cardiac conduction system. These arrhythmias can occur in various different forms of structural heart disease. Here, we review the basic science discoveries and their analogous clinical observations that implicate the His-Purkinje system as a crucial component of the arrhythmia circuit. While mutations serve the molecular basis for arrhythmias in the heritable cardiomyopathies, transcriptional and posttranslational changes constitute the adverse remodeling leading to arrhythmias in acquired structural heart disease. Additional studies on the electrical properties of the His-Purkinje network and its interactions with the surrounding myocardium will improve the clinical diagnosis and treatment of these arrhythmias.

Gender differences in symptoms and functional status in patients with atrial fibrillation undergoing catheter ablation

BACKGROUND

Catheter ablation improves symptoms and quality of life in patients with atrial fibrillation (AF); however, despite its benefit, women are less likely than men to undergo catheter ablation. Women with AF have been described to have more frequent and severe symptoms with a lower quality of life than men, and it is therefore unclear why women are less likely to undergo catheter ablation. We prospectively characterized gender differences in AF symptoms among men and women undergoing ablation at UNC using questionnaire data.

METHODS

Functional capacity was assessed with the Duke Activity Status Index (DASI) and quality of life was assessed with the Canadian Cardiovascular Society Symptoms of AF score (CCS-SAF) and the AF Effect on Quality-of-Life Questionnaire Tool (AFEQT).

RESULTS

Among 191 patients in the study, women were less likely to undergo catheter ablation and had higher rates of paroxysmal AF and higher CHADS₂ -VASc scores than men. Women had a worse functional capacity with significantly lower DASI scores than men; quality of life was also worse among women, with higher CCS-SAF scores and lower AFEQT scores than men. After adjustment for AF type, there was a persistent gender difference for functional capacity and symptom measures.

CONCLUSIONS

At the time of catheter ablation, women with AF had a significantly lower functional status with worse symptoms and a lower quality of life than men. The role of this symptom difference on the gender gap in enrollment for catheter ablation is unclear and likely due to multiple patient and provider factors.

Cardiac implantable electronic device hematomas: Risk factors and effect of prophylactic pressure bandaging

BACKGROUND

Cardiac implantable electronic device (CIED) hematomas are associated with many adverse outcomes. We examined the incidence and risk factors associated with hematoma formation post-CIED implantation, and explored the preventative effect of prophylactic pressure bandaging (PPB) in a large tertiary center.

METHODS

1,091 devices were implanted during October 2011-December 2014. Clinically significant hematomas (CSH) were those that necessitated prolonged admission, including those due to reoperation, and clinically suspicious hematomas were swellings noted by medical/nursing staff. We screened for variables affecting hematoma incidence prior to conducting multivariate logistic regression analyses, one for all hematomas and one for CSH.

RESULTS

61 hematomas were identified (5.6% of patients), with 12 of those clinically significant (1.1% of patients). Factors significantly increasing the odds of developing any hematoma were stage 2 (odds ratio [OR] = 2.93, 95% confidence interval [CI] [1.08-7.94], P = 0.034) and 3 chronic kidney disease (CKD) (OR = 3.39 [1.20-9.56], P = 0.021), unfractionated heparin/therapeutic enoxaparin (OR = 3.15 [1.22-8.14], P = 0.018), and dual antiplatelets-aspirin + clopidogrel (OR = 2.95 [1.14-7.65], P = 0.026) + other combinations. Body Mass index (BMI) 25.0-29.9 (OR 0.52 [0.28-0.98], P = 0.044) and >30 were associated with decreased hematoma risk (OR 0.43 [0.20-0.91], P = 0.028). Factors significant for CSH formation were unfractionated heparin/therapeutic enoxaparin (OR = 9.55 [1.83-49.84], P = 0.007) and aspirin + clopidogrel (OR = 7.19 [1.01-50.91], P = 0.048). PPB nonsignificantly increased the odds of total hematoma development (OR = 1.53 [0.87-2.69], P = 0.135), and reduced CSH (OR = 0.67 [0.18-2.47], P = 0.547).

CONCLUSIONS

Heparin and dual antiplatelet use remain strong predictors of overall hematoma formation. CKD is a comparatively moderate predictor. BMI > 25 may decrease the risk of hematoma formation. PPB had nonsignificant effects on hematoma development.

Initial experience with a novel electrophysiology mapping simulator

BACKGROUND

Despite data supporting the use of simulation training in procedural specialties and accreditation requirements, few options exist for electrophysiology (EP) training. We aimed to develop a low-cost, accessible simulator for training in EP mapping, and to test the simulator in a group of novice users.

METHODS

Our mapping simulator is composed of three components: an acrylic case representing torso and thigh; three-dimensional (3D) printed cardiac models; and a commercially available mapping system. Using a proprietary flexible material that mimics the consistency of human heart tissue, we created an anatomically accurate model of a normal right atrium (RA) from computed tomography data. We developed a test protocol consisting of two activities: creation of a RA shell and timed navigation to specific locations within the RA shell. Seventeen participants were randomized to either practice versus no practice on the simulator, and repeated simulator and self-assessment tests were performed after 1 week. We measured volume of the RA map and time taken and distance from the target sites for each target location.

RESULTS

Both groups showed improvement in generation of geometry, volume, time to target, and self-assessed comfort level after initial exposure to the simulator. Compared with no-practice, the practice group demonstrated an improved sense of confidence in mapping.

CONCLUSIONS

Focused training in EP mapping using a novel simulator created with 3D printed heart models and a standard mapping system is feasible for use in the training environment. Exposure to the simulator is associated with improved mapping skills and trainee comfort level.

Distinct impacts of heart rate and right atrial-pacing on left atrial mechanical activation and optimal AV delay in CRT

BACKGROUND

Controversy exists regarding how atrial activation mode and heart rate affect optimal atrioventricular (AV) delay in cardiac resynchronization therapy. We studied these questions using high-reproducibility hemodynamic and echocardiographic measurements.

METHODS

Twenty patients were hemodynamically optimized using noninvasive beat-to-beat blood pressure at rest (62 ± 11 beats/min), during exercise (80 ± 6 beats/min), and at three atrially paced rates: 5, 25, and 45 beats/min above rest, denoted as Apaced,r+5 , Apaced,r+25 , and Apaced,r+45 , respectively. Left atrial myocardial motion and transmitral flow were timed echocardiographically.

RESULTS

During atrial sensing, raising heart rate shortened optimal AV delay by 25 ± 6 ms (P < 0.001). During atrial pacing, raising heart rate from Apaced,r+5 to Apaced,r+25 shortened it by 16 ± 6 ms; Apaced,r+45 shortened it 17 ± 6 ms further (P < 0.001). In comparison to atrial-sensed activation, atrial pacing lengthened optimal AV delay by 76 ± 6 ms (P < 0.0001) at rest, and at ∼20 beats/min faster, by 85 ± 7 ms (P < 0.0001), 9 ± 4 ms more (P  =  0.017). Mechanically, atrial pacing delayed left atrial contraction by 63 ± 5 ms at rest and by 73 ± 5 ms (i.e., by 10 ± 5 ms more, P < 0.05) at ∼20 beats/min faster. Raising atrial rate by exercise advanced left atrial contraction by 7 ± 2 ms (P  =  0.001). Raising it by atrial pacing did not (P  =  0.2).

CONCLUSIONS

Hemodynamic optimal AV delay shortens with elevation of heart rate. It lengthens on switching from atrial-sensed to atrial-paced at the same rate, and echocardiography shows this sensed-paced difference in optima results from a sensed-paced difference in atrial electromechanical delay. The reason for the widening of the sensed-paced difference in AV optimum may be physiological stimuli (e.g., adrenergic drive) advancing left atrial contraction during exercise but not with fast atrial pacing.

Ventricular asystole in a CRT-D device. What is the mechanism?

We present a case of an 89-year-old man with a left ventricular assist device and cardiac resynchronization therapy device (CRT-D) who presented with multiple presyncopal events. On the night of admission, telemetry revealed a 13-s pause with appropriately timed pacing spikes but with failure to capture, followed by intermittent ventricular contraction with different QRS morphology. What was the mechanism for his ventricular asystole?

Successful cryoablation of left ventricular summit premature ventricular contractions via the coronary sinus

The left ventricular summit (LVS) is a challenging location for catheter-based percutaneous ablation due to its anatomical location. There have been case reports of cryoablations performed in this region, but the technique may be underutilized when radiofrequency ablation fails. A 45-year-old male was found to have 25 000 premature ventricular contractions (PVCs) a day despite previous ablation and a reduced ejection fraction of 40% despite medical therapy. Coronary sinus epicardial mapping revealed the coronary sinus distal region generated activations earlier than the QRS onset by 28 ms. Two separate, 4-minute cryoablations were delivered that suppressed the PVCs within 5 seconds. Alternate energy modalities such as cryo may offer a safer and more viable approach for ablation of LVS in select patients.

His bundle lead implantation for leadless pacemaker pacing-induced cardiomyopathy in persistent left superior vena cava

Persistent left superior vena cava (PLSVC) poses technical challenges to implantation of transvenous cardiac implantable electronic devices. His-bundle pacing is a physiologic pacing strategy to avoid or treat pacing-induced cardiomyopathy. We report a case of His-bundle lead implantation in a patient with PLSVC, absent right SVC, and pacing-induced cardiomyopathy.

Predictors of outcomes in hospitalized patients undergoing pacemaker insertion: Analysis from the national inpatient database (2016-2017)

BACKGROUND

Pacemaker implantation in the U.S. is rising due to an aging population. The aim of this analysis was to identify risk factors associated with increased mortality and complications in hospitalized patients requiring pacemaker implantation.

METHODS

We performed a retrospective analysis using the National Inpatient Sample database, identifying hospitalized patients who underwent pacemaker implantation using International Classification of Disease, Tenth Revision, Clinical Modification codes. Independent predictors of inpatient mortality were identified using multivariate logistic regression analysis.

RESULTS

There were 242,980 hospitalizations with pacemaker implantation during 2016 and 2017. The most frequently encountered indications for hospitalizations involving pacemaker insertion included sick sinus syndrome (SSS) (27.60%), complete atrioventricular (AV) block (21.57%), and second-degree AV block (7.83%). Chronic liver disease was associated with the highest adjusted odds of inpatient mortality (aOR = 5.76, 95% CI: 4.46 to 7.44, p < .001). Comorbid anemia had the highest statistically significant adjusted odds ratio (aOR) for predictors of post-procedural cardiac complications (aOR = 3.17, 95% CI: 2.81 to 3.58, p < .001). Mortality in hospitalized patients needing pacemaker implantation was 1.05%. About 3.36% of hospitalizations developed post procedural circulatory complications (PPCC), 2.45% developed sepsis, and 1.84% developed mechanical complications of cardiac electronic devices.

CONCLUSIONS

We identified several predictors of inpatient mortality in hospitalized patients undergoing pacemaker implantation, including chronic liver disease, protein-calorie malnutrition, chronic heart failure, anemia, and history of malignancy. Anemia, chronic liver disease, and congestive heart failure were independent predictors of adverse outcomes in such patients.

Left common carotid artery to left innominate vein arteriovenous fistula after transvenous laser lead extraction

Transvenous lead extraction (TLE) is used for lead infection, lead debulking, venous recanalization and device upgrades. Lead extraction is performed using specialized tools including locking stylets, mechanical or rotating sheaths, femoral snares or laser sheaths. The most feared complications associated with lead extraction are bleeding, vascular tear, cardiac avulsion and tamponade. Despite technological progress, the incidence of major procedural complications including death remains slightly above 1%. This case depicts an asymptomatic left common carotid artery (LCCA) to left innominate vein arteriovenous fistula (AVF) after laser-assisted TLE successfully treated with an endovascular covered stent.