Association of Ventricular Arrhythmias With Dementia: The Atherosclerosis Risk in Communities (ARIC) Study

Identifying Alzheimer's Disease Progression Subphenotypes via a Graph-based Framework using Electronic Health Records

PURPOSE

Understanding the heterogeneity of neurodegeneration in Alzheimer's disease (AD) development, as well as identifying AD progression pathways, is vital for enhancing diagnosis, treatment, prognosis, and prevention strategies. To identify disease progression subphenotypes in patients with mild cognitive impairment (MCI) and AD using electronic health records (EHRs).

METHODS

We identified patients with mild cognitive impairment (MCI) and AD from the electronic health records from the OneFlorida+ Clinical Research Consortium. We proposed an outcome-oriented graph neural network-based model to identify progression pathways from MCI to AD.

RESULTS

Of the included 2,525 patients, 61.66% were female, and the mean age was 76. In this cohort, 64.83% were Non-Hispanic White (NHW), 16.48% were Non-Hispanic Black (NHB), and 2.53% were of other races. Additionally, there were 274 Hispanic patients, accounting for 10.85% of the total patient population. The average duration from the first MCI diagnosis to the transition to AD was 891 days. We identified four progression subphenotypes, each with distinct characteristics. The average progression times from MCI to AD varied among these subphenotypes, ranging from 805 to 1,236 days.

CONCLUSION

The findings suggest that AD does not follow uniform transitions of disease states but rather exhibits heterogeneous progression pathways. Our proposed framework holds the potential to identify AD progression subphenotypes, providing valuable and explainable insights for the development of the disease.

Role of ideal cardiovascular health metrics in reducing risk of incident arrhythmias

AIMS

Cardiovascular health (CVH) has been proven to reduce cardiovascular disease burden and mortality, but data are lacking regarding cardiac arrhythmias. The aim of this study was to assess the association between CVH metrics and atrial fibrillation/flutter (AF), ventricular arrhythmias, and bradyarrhythmias.

METHODS AND RESULTS

This study analysed data from the Atherosclerosis Risk in Communities (ARIC) cohort, with participants recruited from four different communities across the United States. Cardiovascular health metrics were scored at baseline (1987-89) following the American Heart Association's recommendations and categorized as poor, intermediate, or ideal. Arrhythmia episodes were diagnosed by International Classification of Diseases (ICD)-9 code. Adjusted associations were estimated using Cox models and event rates and population attributable fractions were calculated by CVH metrics category. The study population consisted of 13 078 participants, with 2548 AF, 1363 ventricular arrhythmias, and 706 bradyarrhythmias occurred. The adjusted hazard ratios (HRs) for ideal (vs. poor) CVH metrics were 0.59 [95% confidence interval (CI): 0.50-0.69] for AF, 0.38 (95% CI: 0.28-0.51) for ventricular arrhythmias, and 0.70 (95% CI: 0.51-0.97) for bradyarrhythmia. The risk of incident arrhythmias decreased steadily as the CVH metrics improved from 0 to 14 scores. The adjusted population attributable fractions were calculated to be 29.9% for AF, 54.4% for ventricular arrhythmias, and 21.9% for bradyarrhythmia, respectively. The association between CVH metrics and incident arrhythmias was also seen in people who remained free of coronary heart disease over the follow-up.

CONCLUSION

Achieving ideal CVH metrics recommendations by AHA in midlife was associated with a lower risk of incident arrhythmias later in life.

Premature Ventricular Complexes: Benign versus Malignant - How to approach?

Premature Ventricular Complexes (PVCs) refer to electrical activity arising from ventricles resulting in ventricular contraction independent of the native rhythm. PVCs by themselves are common in the general population but based on the origin of the PVCs, either related to anatomical or electrical substrate, the disease process has a widely varied presentation and prognosis. The clinical presentation of symptoms may vary from being extremely benign, or very severe (malignant). Benign PVCs include those that are asymptomatic or induce very mild symptoms including palpitations, lightheadedness, chest discomfort, or the sensation of skipped beats. The middle range of PVCs present as heart failure or heart failure complicated by PVCs. The malignant variety may present as syncope, or sudden cardiac death. In this review we describe the multiple facets of PVC presentation and strategies of clinical management.

Subclinical Left Ventricular Dysfunction and Ventricular Arrhythmias in Older Adults With Normal Ejection Fraction

Background Premature ventricular contractions (PVCs) and nonsustained ventricular tachycardia (NSVT) are known to be associated with reduced left ventricular (LV) ejection fraction and adverse outcomes in patients with structural heart disease. The relationship between subclinical LV dysfunction and ventricular arrhythmias in the general population is not established. Methods and Results Participants in the SAFARIS (Subclinical Atrial Fibrillation and Risk of Ischemic Stroke) study with normal left ventricular ejection fraction (n=503; mean age 77 years, 63% women) underwent 14-day electrocardiographic monitoring and 2-dimensional echocardiography. Frequent PVCs were defined as PVCs >500 per 24 hours and NSVT as ≥4 consecutive ventricular ectopic beats. Reduced LV global longitudinal strain (GLS) was used as an indicator of subclinical LV dysfunction. Seventy-six participants (15.1%) had PVCs >500/d, 117 (23.3%) had NSVT episodes. LV GLS was significantly reduced in both frequent PVCs and NSVT groups (P<0.01). In multivariable analyses, lower LV GLS was associated with frequent PVCs (adjusted odds ratio [aOR], 1.19 [95% CI, 1.09-1.30 per unit reduction]; P<0.001) and NSVT (aOR, 1.09 [95% CI, 1.01-1.17]; P=0.036) independently of established risk factors and other echocardiographic parameters. Abnormal LV GLS (>-15.8%) carried a 2-fold increase in risk of ventricular arrhythmias (aOR, 2.18, P=0.029 for PVCs; aOR, 2.09, P=0.026 for NSVT). Conclusions PVCs and NSVT episodes were frequent in this community-based elderly cohort with normal left ventricular ejection fraction and were independently associated with lower LV GLS. The association between LV dysfunction and ventricular arrhythmias is present at an early, subclinical stage, an observation that carries possible preventative implications.

Arrhythmia and other modifiable risk factors in incident dementia and MCI among elderly individuals with low educational levels in Taiwan

Introduction

There is increasing evidence that arrhythmia is a risk factor for dementia; however, it appears that arrhythmia affects the cognitive function of individuals differentially across age groups, races, and educational levels. Demographic differences including educational level have also been found to moderate the effects of modifiable risk factors for cognitive decline.

Methods

This study recruited 1,361 individuals including a group of cognitively unimpaired (CU) individuals, a group of patients with mild cognitive impairment (MCI), and a group of patients with dementia with low education levels. The participants were evaluated in terms of modifiable risk factors for dementia, including arrhythmia and neuropsychiatric symptoms.

Results

Cox proportional hazard regression models revealed that among older MCI patients (>75 years), those with arrhythmia faced an elevated risk of dementia. Among younger MCI patients, those taking anti-hypertensive drugs faced a relatively low risk of dementia. Among younger MCI patients, male sex and higher educational level were associated with an elevated risk of dementia. Among CU individuals, those with coronary heart disease and taking anti-lipid compounds faced an elevated risk of MCI and those with symptoms of depression faced an elevated risk of dementia.

Discussion

The risk and protective factors mentioned above could potentially be used as markers in predicting the onset of dementia in clinical settings, especially for individuals with low educational levels.

Cerebral haemodynamics during arrhythmia in health, ischaemic heart disease and heart failure with reduced ejection fraction, and in a preclinical swine model

Ventricular arrhythmias are associated with neurological impairment and could represent a source of cerebral hypoperfusion. In the present study, data from healthy individuals (n = 11), patients with ischaemic heart disease (IHD; ejection fraction >40%; n = 9) and patients with heart failure with reduced ejection fraction (HFrEF; EF = 31 (5)%, n = 11), as well as data from swine surgeries, where spontaneous ventricular arrhythmias were observed during cerebrovascular examination (transcranial Doppler ultrasound in humans and laser Doppler in swine) were analysed retrospectively to investigate the effect of arrhythmia on cerebral microvascular haemodynamics. A subset of participants also completed the Montreal Cognitive Assessment (MoCA). Middle cerebral artery mean blood velocity (MCA_Vmean ) decreased during premature ventricular contraction (PVC) in all groups, and data from swine indicate PVCs reduced cerebral microvascular perfusion. Overall MCA_Vmean was decreased in the HFrEF vs. control group. Further, %∆MCA_Vmean /%∆mean arterial pressure during the PVC was greater in the HFrEF vs. control group and was correlated with decreased MoCA scores. Subanalysis of HFrEF data revealed that during bigeminy MCA_Vmean decreased owing to reductions during irregular beats only. During non-sustained ventricular tachycardia, MCA_Vmean decreased but recovered above baseline upon return to sinus rhythm. Also, haemodynamic perturbations during and following the PVC were greater in the brachial artery vs. the MCA. Therefore, ventricular arrhythmias decreased indices of cerebral perfusion irrespective of IHD or HFrEF. The relative magnitude of arrhythmia-induced haemodynamic perturbations appears to be population specific and arrhythmia type and organ dependent. The cumulative burden of arrhythmia-induced deficits may exacerbate existing cerebral hypoperfusion in HFrEF and contribute to neurological abnormalities in this population. KEY POINTS: Irregular heartbeats are often considered benign in isolation, but individuals who experience them frequently have a higher prevalence of cerebrovascular and/or cognitive associated disorders. How irregular heartbeats affect blood pressure and cerebral haemodynamics in healthy and cardiovascular disease patients, those with and without reduced ejection fraction, remains unknown. Here it was found that in the absence of symptoms associated with irregular heartbeats, such as dizziness or hypotension, single, multiple non-sustained and sustained irregular heartbeats influence cerebral haemodynamics in a population-specific, arrhythmia-type and organ-dependent manner. Relative deficits in the index of cerebral blood flow normalized to relative deficits in blood pressure were greatest in patients with heart failure with reduced ejection and inversely related with cognitive performance. Chronic arrhythmias may exacerbate existing cerebral hypoperfusion in heart failure with reduced ejection fraction, thereby providing a mechanistic link between otherwise benign irregular heartbeats and cognitive dysfunction, independent of embolism.

Differences in Left Atrial Size and Function and Supraventricular Ectopy Between Black and White Participants in the ARIC Study

Background Black Americans have more atrial fibrillation risk factors but lower atrial fibrillation risk than White Americans. Left atrial (LA) enlargement and/or dysfunction, frequent atrial tachycardia (AT), and premature atrial contractions (PAC) are associated with increased atrial fibrillation risk. Racial differences in these factors may exist that could explain the difference in atrial fibrillation risk. Methods and Results We included 2133 ARIC (Atherosclerosis Risk in Communities) study participants (aged 74±4.5 years[mean±SD], 59% women, 27% Black participants) who had echocardiograms in 2011 to 2013 and wore the Zio XT Patch (a 2-week continuous heart monitor) in 2016 to 2017. Linear regression was used to analyze (1) differences in AT/day or PAC/hour between Black and White participants, (2) differences in LA measures between Black and White participants, and (3) racial differences in the association of LA measures with AT or PAC frequency. Compared with White participants, Black participants had a higher prevalence of cardiovascular risk factors and disease, lower AT frequency, greater LA size, and lower LA function. After multivariable adjustments, Black participants had 37% (95% CI, 24%-47%) fewer AT runs/day than White participants. No difference in PAC between races was noted. Greater LA size and reduced LA function are associated with more AT and PAC runs; however, no race interaction was present. Conclusions Differences in LA measures are unlikely to explain the difference in atrial fibrillation risk between Black and White individuals. Despite more cardiovascular risk factors and greater atrial remodeling, Black participants have lower AT frequency than White participants. Future research is needed to elucidate the protective mechanisms that confer resilience to atrial arrhythmias in Black individuals.

Smart Wearables for Cardiac Monitoring-Real-World Use beyond Atrial Fibrillation

The possibilities and implementation of wearable cardiac monitoring beyond atrial fibrillation are increasing continuously. This review focuses on the real-world use and evolution of these devices for other arrhythmias, cardiovascular diseases and some of their risk factors beyond atrial fibrillation. The management of nonatrial fibrillation arrhythmias represents a broad field of wearable technologies in cardiology using Holter, event recorder, electrocardiogram (ECG) patches, wristbands and textiles. Implementation in other patient cohorts, such as ST-elevation myocardial infarction (STEMI), heart failure or sleep apnea, is feasible and expanding. In addition to appropriate accuracy, clinical studies must address the validation of clinical pathways including the appropriate device and clinical decisions resulting from the surrogate assessed.