New-onset atrial fibrillation and thromboembolic risk: Cardiovascular syzygy?

New-onset as opposed to established atrial fibrillation as a risk factor for incident stroke

BACKGROUND

Atrial fibrillation (AF) is an established risk factor for acute ischemic stroke (AIS). It remains unclear if new-onset AF confers a higher risk of AIS than longer-standing AF.

METHODS

We retrospectively analyzed all stroke-free patients who underwent transthoracic echocardiography (TTE) in the Henry Ford Health System between March 6 and September 6, 2016. Incident AIS and new-onset AF were ascertained by the presence of new diagnostic codes in the electronic medical record over a follow-up period of up to 5 years. Cox proportional hazards regression was used to identify risk factors for new-onset AF or AIS.

RESULTS

Of 7310 patients who underwent baseline TTE the mean age was 65 years, 54% were female, 51% were Caucasian, and 46% had left atrial enlargement (LAE). Of at-risk patients, 10.9% developed new-onset AF and 2.9% experienced incident AIS. The risk of new-onset AF among at-risk patients was 3.1 times higher among patients with any degree of LAE compared to those with normal LA size (95% CI 2.6-3.6, P < 0.0001). New-onset AF, more than established AF, in turn had a powerful association with incident AIS. The cumulative 5-year risk of AIS was 3.5% in those without AF, 5.9% in those with established AF prior to TTE, and 20.1% in those with new-onset AF (P < 0.0001). In multivariable analysis new-onset AF had the strongest association with incident AIS (P < 0.0001), followed by increasing age (P = 0.0025), black race (P = 0.0032), and smoking (P = 0.0063).

CONCLUSIONS

New-onset AF has a strong relationship with incident AIS. LAE was present in nearly half of stroke-free patients undergoing TTE, and was associated with a significantly higher likelihood of new-onset AF during follow-up. Vigilant cardiac monitoring for AF in individuals with LAE, coupled with the timely initiation of anticoagulation, may be an important strategy for the primary prevention of AF-related stroke.

Development and validation of a nomogram for predicting atrial fibrillation in patients with acute heart failure admitted to the ICU: a retrospective cohort study

INTRODUCTION

Acute heart failure is a serious condition. Atrial fibrillation is the most frequent arrhythmia in patients with acute heart failure. The occurrence of atrial fibrillation in heart failure patients worsens their prognosis and leads to a substantial increase in treatment costs. There is no tool that can effectively predict the onset of atrial fibrillation in patients with acute heart failure in the ICU currently.

MATERIALS AND METHODS

We retrospectively analyzed the MIMIC-IV database of patients admitted to the intensive care unit (ICU) for acute heart failure and who were initially sinus rhythm. Data on demographics, comorbidities, laboratory findings, vital signs, and treatment were extracted. The cohort was divided into a training set and a validation set. Variables selected by LASSO regression and multivariate logistic regression in the training set were used to develop a model for predicting the occurrence of atrial fibrillation in acute heart failure in the ICU. A nomogram was drawn and an online calculator was developed. The discrimination and calibration of the model was evaluated. The performance of the model was tested using the validation set.

RESULTS

This study included 2342 patients with acute heart failure, 646 of whom developed atrial fibrillation during their ICU stay. Using LASSO and multiple logistic regression, we selected six significant variables: age, prothrombin time, heart rate, use of vasoactive drugs within 24 h, Sequential Organ Failure Assessment (SOFA) score, and Acute Physiology Score (APS) III. The C-index of the model was 0.700 (95% CI 0.672-0.727) and 0.682 (95% CI 0.639-0.725) in the training and validation sets, respectively. The calibration curves also performed well in both sets.

CONCLUSION

We developed a simple and effective model for predicting atrial fibrillation in patients with acute heart failure in the ICU.

Clinical Outcomes in Asymptomatic and Symptomatic Atrial Fibrillation Presentations in GARFIELD-AF: Implications for AF Screening

BACKGROUND

Asymptomatic atrial fibrillation is often detected incidentally. Prognosis and optimal therapy for asymptomatic compared with symptomatic atrial fibrillation is uncertain. This study compares clinical characteristics, treatment, and 2-year outcomes of asymptomatic and symptomatic atrial fibrillation presentations.

METHODS

Global Anticoagulant Registry in the Field-Atrial Fibrillation (GARFIELD-AF) is a global, prospective, observational study of newly diagnosed atrial fibrillation with ≥1 stroke risk factors (http://www.clinicaltrials.gov, unique identifier: NCT01090362). Patients were characterized by atrial fibrillation-related symptoms at presentation and the CHA₂DS₂-VASc score. Two-year follow-up recorded anticoagulation patterns (vitamin K antagonist, direct oral anticoagulants, parenteral therapy) and outcomes (stroke/systemic embolism, all-cause mortality, and bleeding).

RESULTS

At presentation, of 52,032 eligible patients, 25.4% were asymptomatic and 74.6% symptomatic. Asymptomatic patients were slightly older (72 vs 70 years), more often male (64.2% vs 52.9%), and more frequently initiated on anticoagulation ± antiplatelets (69.4% vs 66.0%). No difference in events (adjusted hazard ratios, 95% confidence interval) for nonhemorrhagic stroke/systemic embolism (1.19, 0.97-1.45), all-cause mortality (1.06, 0.94-1.20), or bleeding (1.02, 0.87-1.19) was observed. Anticoagulation was associated with comparable reduction in nonhemorrhagic stroke/systemic embolism (0.59, 0.43-0.82 vs 0.78, 0.65-0.93) and all-cause mortality (0.69, 0.59-0.81 vs 0.77, 0.71-0.85) in asymptomatic versus symptomatic, respectively.

CONCLUSIONS

Major outcomes do not differ between asymptomatic and symptomatic atrial fibrillation presentations and are comparably reduced by anticoagulation. Opportunistic screening-detected asymptomatic atrial fibrillation likely has the same prognosis as asymptomatic atrial fibrillation at presentation and likely responds similarly to anticoagulation thromboprophylaxis.

Continuous heart rhythm monitoring using mobile photoplethysmography in ambulatory patients

BACKGROUND

Wearable devices using photo-plethysmography (PPG) can accurately detect heart beats and may be useful for heart rate measurement and diagnosis of arrhythmias such as atrial fibrillation (AF). A previous study of a new portable PPG sensor (CardiacSense) showed high accuracy in heart rate measurement and AF detection in resting patients. We report a trial done to test the same device in active ambulatory patients with diverse characteristics.

METHODS

A cohort of 24 ambulatory volunteers, underwent simultaneous PPG recording and continuous electrocardiogram (ECG) recording under different environmental conditions and situations. Per study protocol, the subjects were diverse in age, BMI, hair density and skin tone. Four subjects had AF. Heart rate measurement using the PPG device was compared to measurements by ECG.

RESULTS

Of 163,527 recorded ECG-detected beats in the trial, 86,929 (53.2%) were also recorded by the PPG device. Most undetected heart beats were due to motion induced noise. Correlation between ECG and PPG was high (R = 0.94, p < 0.0001), yet in subjects with AF correlation was lower (R = 0.80, p < 0.0001). A Bland-Altman analysis showed the mean difference between measurements was -0.7 ms (95% limit of agreement -93.8 to 92.2). A total of 86,217 (99.9%) of all RR measurements were reliably measured (RR difference within 100 ms). Reliability was sustained (>99.8%) in subjects of all groups including subjects with AF.

CONCLUSIONS

This study showed that, in the absence of movement-related noise, the CardiacSense PPG device can reliably detect HR in a variety of situations and subjects' characteristics.

Predictors of acute hospital mortality and length of stay in patients with new-onset atrial fibrillation: a first-hand experience from a medical emergency team response provider

BACKGROUND

Atrial fibrillation (AF) occurs frequently following cardiothoracic surgery and treatment decisions are informed by evidence-based clinical guidelines. Outside this setting there are few data to guide clinical management.

AIM

To describe the characteristics, management and outcomes of hospitalised adult patients with new-onset AF.

METHODS

The medical emergency team (MET) database was utilised to identify patients who had a 'MET call' activated for tachycardia between 2015 and 2016. Patients with sinus tachycardia, pre-existing AF/atrial flutter or other known tachyarrhythmia were excluded. Primary outcomes were length of hospital stay and in-hospital mortality.

RESULTS

New-onset AF was identified in 137 patients: 68 medically managed; 38 non-cardiothoracic post-operative; and 31 cardiothoracic post-operative. Mean age was 74 ± 11.6 years and 72 (53%) were male. Of 79 patients who underwent echocardiography, 80% had left atrial dilatation and 14% had reduced left ventricular ejection fraction (LVEF). Mean length of stay (LOS) was 12 days and in-hospital mortality rate was 11%. On multivariable analysis, the odds of death during acute hospitalisation was 7.4 times higher in patients with heart failure with reduced LVEF (odds ratio 7.4, 95% confidence interval (CI) 1.23-44.8, P = 0.028). Length of acute hospital stay increased by 36% if the duration of AF was longer than 48 h (beta coefficient 0.36, 95% CI -0.015 to 0.74, P = 0.059).

CONCLUSION

Left ventricular systolic dysfunction in hospitalised patients with new-onset AF is associated with increased all-cause mortality whereas lower serum potassium levels are associated with an increased LOS. A prospective study is planned to compare outcomes based on in-hospital treatment strategies.

Ischemic Stroke and Transient Ischemic Attack Risk Following Vitamin K Antagonist Cessation in Newly Diagnosed Atrial Fibrillation: A Cohort Study

Background In nonvalvular atrial fibrillation (AF), oral anticoagulants prevent ischemic strokes and transient ischemic attacks (TIAs), but nonpersistence with vitamin K antagonist (VKA) oral anticoagulant therapy (20-50% at 1 year) is problematic. The precise risk of stroke/TIA after VKA cessation and its time course during extended follow-up is unknown. Methods and Results The study cohort of incident AF in patients receiving initial VKA between 2001 and 2013 was identified from the UK Clinical Practice Research Datalink (linked hospitalizations and causes of death). Using a nested case-control analysis, patients with incident stroke/TIA were matched to patients without stroke/TIA (controls). Relative risk with time since VKA cessation compared with current VKA use was approximated from conditional logistic regression. We studied 16 696 patients with incident AF and initial VKA treatment. There were 489 stroke/TIA cases matched to 2137 controls (mean CHA₂DS₂-VASc score 4.3). Compared with current VKA use, the excess incidence rate of stroke/TIA following VKA cessation in the first year after AF diagnosis was 2.29 (95% CI, 0.98-3.90) per 100 person-years of VKA cessation or 1 additional stroke/TIA per 43 patients per year discontinuing VKA, compared with 1.43 (95% CI, 0.97-1.88) per 100 person-years corresponding to 1 additional stroke/TIA per 70 patients per year, when VKA was discontinued more than 1 year after AF diagnosis. Conclusions VKA cessation is associated with a continuous excess thromboembolic stroke/TIA risk. Increasing oral anticoagulant persistence, especially in the year after AF diagnosis, should be a therapeutic target to reduce stroke/TIA in AF.

Comparative thromboembolic risk in atrial fibrillation with and without a secondary precipitant-Danish nationwide cohort study

OBJECTIVES

We compared long-term outcomes in patients with atrial fibrillation (AF) with and without a secondary precipitant.

DESIGN AND SETTING

Retrospective cohort study based on Danish nationwide registries.

PARTICIPANTS

Patients with AF with and without secondary precipitants (1996-2015) were matched 1:1 according to age, sex, calendar year, CHA₂DS₂-VASc score and oral anticoagulation therapy (OAC), resulting in a cohort of 39 723 patients with AF with a secondary precipitant and the same number of patients with AF without a secondary precipitant. Secondary precipitants included alcohol intoxication, thyrotoxicosis, myocardial infarction, surgery and infection in conjunction with AF.

PRIMARY AND SECONDARY OUTCOMES

The primary outcome in this study was thromboembolic events. Secondary outcomes included AF rehospitalisation and death. Long-term risks of outcomes were examined by multivariable Cox regression analysis.

RESULTS

The most common precipitants were infection (55.0%), surgery (13.2%) and myocardial infarction (12.0%). The 5-year absolute risk of thromboembolic events (taking death into account as a competing risk) in patients with AF grouped according to secondary precipitants were 8.3% (alcohol intoxication), 8.5% (thyrotoxicosis), 12.1% (myocardial infarction), 11.6% (surgery), 12.2% (infection), 10.1% (>1 precipitant) and 12.3% (no secondary precipitant). In the multivariable analyses, AF with a secondary precipitant was associated with the same or an even higher thromboembolic risk than AF without a secondary precipitant. One exception was patients with AF and thyrotoxicosis: those not initiated on OAC therapy carried a lower thromboembolic risk the first year of follow-up than matched patients with AF without a secondary precipitant and no OAC therapy.

CONCLUSIONS

In general, AF with a secondary precipitant was associated with the same thromboembolic risk as AF without a secondary precipitant. Consequently, this study highlights the need for more research regarding the long-term management of patients with AF associated with a secondary precipitant.

Asymmetric and Symmetric Dimethylarginine Predict Outcomes in Patients With Atrial Fibrillation: An ARISTOTLE Substudy

BACKGROUND

There is little mechanistic information on factors predisposing atrial fibrillation (AF) patients to thromboembolism or bleeding, but generation of nitric oxide (NO) might theoretically contribute to both.

OBJECTIVES

The authors tested the hypothesis that plasma levels of the methylated arginine derivatives asymmetric and symmetric dimethylarginine (ADMA/SDMA), which inhibit NO generation, might be associated with outcomes in AF.

METHODS

Plasma samples were obtained from 5,004 patients with AF at randomization to warfarin or apixaban in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial. ADMA and SDMA concentrations were measured by high-performance liquid chromatography. Relationships to clinical characteristics were evaluated by multivariable analyses. Associations with major outcomes, during a median of 1.9 years follow-up, were evaluated by adjusted Cox proportional hazards models.

RESULTS

Both ADMA and SDMA plasma concentrations at study entry increased significantly with patients' age, female sex, renal impairment, permanent AF, or congestive heart failure. ADMA and SDMA increased (p < 0.001) with both increased CHA₂DS₂-VASc and HAS-BLED scores, but decreased in the presence of diabetes. On multivariable analysis adjusting for established risk factors and treatment, tertile groups of ADMA concentrations were significantly associated with stroke/systemic embolism (p = 0.034), and death (p < 0.0001), whereas tertile groups of SDMA were associated with major bleeding and death (p < 0.001 for both). Incorporating ADMA and SDMA into CHA₂DS₂-VASc or HAS-BLED predictive models improved C-indices for those outcomes. Neither ADMA nor SDMA predicted differential responses to warfarin or apixaban.

CONCLUSIONS

In anticoagulated patients with AF, elevated ADMA levels are weakly associated with thromboembolic events, elevated SDMA levels with bleeding events and both are strongly associated with increased mortality. These findings suggest that disturbances of NO function modulate both thrombotic and hemorrhagic risk in anticoagulated patients with AF. (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation [ARISTOTLE]; NCT00412984).

Continuous heart rate monitoring for automatic detection of atrial fibrillation with novel bio-sensing technology

BACKGROUND

Asymptomatic atrial fibrillation [AF] is an important cause of fatal or disabling stroke. A continuous heart-rate monitoring device, comfortable enough to be worn continuously and reliable enough to detect AF, would allow for prompt initiation of anticoagulation therapy to prevent stroke.

METHODS

We studied a new custom-made wearable photo-plethysmograph [PPG] wrist-watch sensor, specifically designed for continuous heart rate monitoring and incorporating contact and motion noise-filters. We tested its ability to automatically detect AF in patients undergoing elective cardioversion of AF, using simultaneously recorded electrocardiogram [ECG] as gold standard.

RESULTS

A total of 18,608 consecutive R-R-interval measurements were recorded simultaneously with PPG and ECG in 20 patients, including 12,521 [67.3%] R-R-intervals during AF and 6087 [32.7%] R-R intervals during sinus rhythm. Scatter plots and Bland-Altman plots demonstrated that the PPG signals were highly correlated to the simultaneously recorded ECG [R = 0.980, p < 0.001], both during AF and during sinus rhythm. The automatic algorithm distinguished AF from sinus rhythm with a sensitivity of 100% and specificity of 93.1%.

CONCLUSIONS

This PPG-based wrist-watch sensor reliably detected AF in non-ambulatory patients.

Safely Addressing Patients with Atrial Fibrillation to Early Anticoagulation after Acute Stroke

BACKGROUND

It has been widely reported that anticoagulants (ACs) are underused for primary and secondary prevention of ischemic stroke in patients with atrial fibrillation (AFib). Furthermore, precise evidence-based guidelines about the best timing for AC initiation after acute stroke are currently lacking.

METHODS AND RESULTS

In this retrospective, observational study, we analyzed prescription trends in AFib patients with acute ischemic stroke who were hospitalized in four neurologic stroke units of our region (Lombardia, Italy). In-hospital antithrombotic prescription was performed in highly heterogeneous patterns. A prestroke treatment with AC was the leading factor enhancing AC prescription during hospitalization. The other factors promoting AC were male gender, younger age, lower prestroke disability and stroke severity, and smaller stroke volumes. AFib subtype influenced AC prescription only in AC-naïve patients. Interestingly, Congestive heart failure, Hypertension, Age higher than 75 years, Diabetes, previous Stroke or TIA or thromboembolism, Vascular disease, Age 64-75 years, female Sex (CHA₂DS₂-VASc) and Hypertension, Abnormal renal and liver function, Stroke, Bleeding, Labile INRs, Elderly, Drugs and alcohol (HAS-BLED) scores were not associated with AC prescription. However, patients who were treated with AC, including early treatment (<48 hours), showed a low rate of bleeding.

CONCLUSIONS

Our findings potentially suggest that, although apparently neglecting the common risk stratification tools, our neurologists were able to select the more suitable candidates for prompt AC treatment. Further studies are needed to develop new scoring systems to aid ischemic and hemorrhagic risk estimation in the secondary prevention of stroke.