Frequent Premature Atrial Contractions Are Associated With Poorer Cognitive Function in the Atherosclerosis Risk in Communities (ARIC) Study

Objective: To evaluate the association of premature atrial contraction (PAC) frequency with cognitive test scores and prevalence of dementia or mild cognitive impairment (MCI). Materials and Methods: We conducted a cross-sectional analysis using Atherosclerosis Risk in Communities study visit 6 (January 1, 2016, through December 31, 2017) data. We included 2163 participants without atrial fibrillation (AF) (age mean ± SD, 79±4 years; 1273 (58.9%) female; and 604 (27.97.0% Black) who underwent cognitive testing and wore a leadless, ambulatory electrocardiogram monitor for 14 days. We categorized PAC frequency based on the percent of beats: less than 1%, minimal; 1% to <5%, occasional; greater than or equal to 5%, frequent. We derived cognitive domain-specific factor scores (memory, executive function, language, and global z-score). Dementia and MCI were adjudicated. Results: During a mean analyzable time of 12.6±2.6 days, 339 (15.7%) had occasional PACs and 107 (4.9%) had frequent PACs. Individuals with frequent PACs (vs minimal) had lower executive function factor scores by 0.30 (95% CI, -0.46 to -0.14) and lower global factor scores by 0.20 (95% CI, -0.33 to -0.07) after multivariable adjustment. Individuals with frequent PACs (vs minimal) had higher odds of prevalent dementia or MCI after multivariable adjustment (odds ratio, 1.74; 95% CI, 1.09 to 2.79). These associations were unchanged with additional adjustment for stroke. Conclusion: In community-dwelling older adults without AF, frequent PACs were cross-sectionally associated with lower executive and global cognitive function and greater prevalence of dementia or MCI, independently of stroke. Our findings lend support to the notion that atrial cardiomyopathy may be a driver of AF-related outcomes. Further research to confirm these associations prospectively and to elucidate underlying mechanisms is warranted

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

Objective We performed a cross-sectional analysis to determine whether nonsustained ventricular tachycardia (NSVT) and premature ventricular contractions (PVCs) were associated with dementia in a population-based study. Methods We included 2,517 (mean age 79 years, 26% Black) participants who wore a 2-week ambulatory continuous ECG recording device in 2016 to 2017. NSVT was defined as a wide-complex tachycardia ≥4 beats with a rate >100 bpm. We calculated NSVT and PVC burden as the number of episodes per day. Dementia was adjudicated by experts. We used logistic regression to assess the associations of NSVT and PVCs with dementia. Results The mean recording time of the Zio XT Patch was 12.6 ± 2.6 days. There were 768 (31%) participants with NSVT; prevalence was similar in White and Black participants. There were 134 (6.5%) dementia cases (5% in White, 10% in Black participants). After multivariable adjustment, there was no overall association between NSVT and dementia; however, there was a significant race interaction (p < 0.001). In Black participants, NSVT was associated with a 3.67 times higher adjusted odds of dementia (95% confidence interval [CI] 1.92-7.02) compared to those without NSVT, whereas in White participants NSVT was not associated with dementia (odds ratio [95% CI] 0.64 [0.37-1.10]). In Black participants only, a higher burden of PVCs was associated with dementia. Conclusions Presence of NSVT and a higher burden of NSVT and PVCs are associated with dementia in elderly Black people. Further research to confirm this novel finding and to elucidate the underlying mechanisms is warranted

Prevalence and characteristics of subclinical atrial fibrillation in a community-dwelling elderly population: The ARIC study

Background: The prevalence of subclinical atrial fibrillation (AF) in the elderly general population is unclear. We sought to define the prevalence of subclinical AF in a community-based elderly population and to characterize subclinical AF and the incremental diagnostic yield of 4 versus 2 weeks of continuous ECG monitoring. Methods: We conducted a cross-sectional analysis within the community-based multicenter observational ARIC study (Atherosclerosis Risk in Communities) using visit 6 (2016-2017) data. The 2616 ARIC study participants who wore a leadless, ambulatory ECG monitor (Zio XT Patch) for up to 2 weeks were aged 79±5 years, 42% men, and 26% black. In a subset, 386 participants without clinically recognized AF wore the monitor twice, each time for up to 2 weeks. We characterized the prevalence of subclinical AF (ie, AF detected on the Zio XT Patch without clinically recognized AF) over 2 weeks of monitoring and the diagnostic yield of 4 versus 2 weeks of monitoring. Results: The prevalence of subclinical AF was 2.5%; the prevalence of subclinical AF was 3.3% among white men, 2.5% among white women, 2.1% among black men, and 1.6% among black women. Subclinical AF was mostly intermittent (75%). Among those with intermittent subclinical AF, 91% had AF burden ≤10% during the monitoring period. In a subset of 386 participants without clinical AF, 78% more subclinical AF was detected by 4 weeks versus 2 weeks of ECG monitoring. Conclusions: In our study, the prevalence of subclinical AF was lower than previously reported and monitoring beyond 2 weeks provided substantial incremental diagnostic yield. Future studies should focus on individuals with higher risk to increase diagnostic yield and consider continuous monitoring duration longer than 2 weeks

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease