A Comparison of Patient History- and EKG-based Cardiac Risk Scores.

Patient-specific risk scores are used to identify individuals at elevated risk for cardiovascular disease. Typically, risk scores are based on patient habits and medical history - age, sex, race, smoking behavior, and prior vital signs and diagnoses. We explore an alternative source of information, a patient's raw electrocardiogram recording, and develop a score of patient risk for various outcomes. We compare models that predict adverse cardiac outcomes following an emergency department visit, and show that a learned representation (e.g. deep neural network) of raw EKG waveforms can improve prediction over traditional risk factors. Further, we show that a simple model based on segmented heart beats performs as well or better than a complex convolutional network recently shown to reliably automate arrhythmia detection in EKGs. We analyze a large cohort of emergency department patients and show evidence that EKG-derived scores can be more robust to patient heterogeneity

Deepr: A Convolutional Net for Medical Records

Feature engineering remains a major bottleneck when creating predictive systems from electronic medical records. At present, an important missing element is detecting predictive regular clinical motifs from irregular episodic records. We present Deepr (short for Deep record), a new end-to-end deep learning system that learns to extract features from medical records and predicts future risk automatically. Deepr transforms a record into a sequence of discrete elements separated by coded time gaps and hospital transfers. On top of the sequence is a convolutional neural net that detects and combines predictive local clinical motifs to stratify the risk. Deepr permits transparent inspection and visualization of its inner working. We validate Deepr on hospital data to predict unplanned readmission after discharge. Deepr achieves superior accuracy compared to traditional techniques, detects meaningful clinical motifs, and uncovers the underlying structure of the disease and intervention space

Risk of thromboembolism in patients developing critical illness-associated atrial fibrillation.

Although common, the long-term significance of -developing atrial fibrillation (AF) during a period of critical illness is unclear. We undertook a retrospective cohort analysis to -assess the rate of thromboembolism (TE) in patients -developing atrial fibrillation de novo during admission to our intensive care unit. In total, 1,955 patients were followed up (-maximum follow-up 1,276 days) for the occurrence of TE, of which 220 (11.3%) had developed AF or atrial flutter during their critical care admission. There were 11 TE events among the patients with new AF (0.053 events per patient-year), compared with 18 in the non-AF group (0.0059 events per patient-year). The unadjusted hazard ratio for TE in patients developing new AF compared with those not developing AF was 8.09 (95% CI 3.08-17.19, p<0.001). In patients admitted to critical care, the development of AF appears to be associated with a significantly increased risk of subsequent thromboembolism

Risk of thromboembolism in patients developing critical illness-associated atrial fibrillation

This is the author accepted manuscript. The final version is available from the Royal College of Physicians via the DOI in this record.Although common, the long-term significance of developing atrial fibrillation (AF) during a period of critical illness is unclear. We undertook a retrospective cohort analysis to assess the rate of thromboembolism (TE) in patients developing atrial fibrillation de novo during admission to our intensive care unit. 1955 patients were followed up (maximum follow-up 1276 days) for the occurrence of TE, of which 220 (11.3%) had developed AF or atrial flutter during their critical care admission. There were 11 TE events among the patients with new AF (0.053 events per patientyear), compared with 18 in the non-AF group (0.0059 events per patient-year). The unadjusted hazard ratio for TE in patients developing new AF compared with those not developing AF was 8.09 (95% CI 3.08 – 17.19, p<0.001). In patients admitted to critical care, the development of AF appears to be associated with a significantly increased risk of subsequent thromboembolism

Atrial fibrillation and frailty: An observational cohort study using electronic healthcare records

Atrial fibrillation is common in older people, and is associated with increased mortality and stroke. Patients with atrial fibrillation/flutter (AF) also commonly have frailty, which is associated with increased risk of a range of further adverse clinical outcomes. However, there is a lack of evidence on the burden and management of AF in people with frailty. A study using the primary care electronic health records of 536,955 patients aged ≥65 years was conducted to investigate the burden of frailty and AF amongst older people, and their associations with clinical outcomes. A systematic review and meta-analysis was completed to establish the current knowledge base, and to inform the quantitative analyses. Baseline characteristics were described and compared between those with and without AF as well as by frailty category according to the electronic frailty index. Rates of all-cause mortality, stroke, bleeding (intracranial and gastrointestinal), transient ischaemic attack (TIA), and falls were calculated per 1000 person-years, and compared with the non-AF patient population. Cox proportional hazards modelling was used to determine unadjusted and adjusted risk for each clinical outcome and mortality, and presented as hazard ratios (HR) alongside 95% confidence intervals. The association between oral anticoagulation (OAC) prescription stratified by frailty category with clinical outcomes was investigated using Cox proportional hazards modelling. At baseline, 61,177 (11.4%) patients had AF. People with AF had a higher burden of frailty than those without (89.5% vs. 55.3%) and had higher rates of mortality, stroke, TIA and bleeding. Of patients with AF and eligible for OAC, it was prescribed in 53.1% (41.7% in robust, mild frailty 53.2%, moderate 55.6%, severe 53.4%). OAC was associated with a 19% reduction in all-cause mortality (HR 0.81, 95%CI 0.77-0.85) and 22% reduction in stroke (HR 0.78, 0.67-0.92). There was no statistically significant difference in rates of bleeding between those prescribed and not prescribed OAC. For the first time in a large representative cohort of older people, this study quantified the burden of AF and frailty, and their association with a range of clinical outcomes. This study found no evidence that OAC should be withheld on the basis of concomitant frailty

Study protocol: The DESPATCH study: Delivering stroke prevention for patients with atrial fibrillation - a cluster randomised controlled trial in primary healthcare

Background: Compelling evidence shows that appropriate use of anticoagulation in patients with nonvalvular atrial fibrillation reduces the risk of ischaemic stroke by 67% and all-cause mortality by 26%. Despite this evidence, anticoagulation is substantially underused, resulting in avoidable fatal and disabling strokes.Methods: DESPATCH is a cluster randomised controlled trial with concealed allocation and blinded outcome assessment designed to evaluate a multifaceted and tailored implementation strategy for improving the uptake of anticoagulation in primary care. We have recruited general practices in South Western Sydney, Australia, and randomly allocated practices to receive the DESPATCH intervention or evidence-based guidelines (control). The intervention comprises specialist decisional support via written feedback about patient-specific cases, three academic detailing sessions (delivered via telephone), practice resources, and evidence-based information. Data for outcome assessment will be obtained from a blinded, independent medical record audit. Our primary endpoint is the proportion of nonvalvular atrial fibrillation patients, over 65 years of age, receiving oral anticoagulation at any time during the 12-month posttest period.Discussion: Successful translation of evidence into clinical practice can reduce avoidable stroke, death, and disability due to nonvalvular atrial fibrillation. If successful, DESPATCH will inform public policy, providing quality evidence for an effective implementation strategy to improve management of nonvalvular atrial fibrillation, to close an important evidence-practice gap.Trial registration: Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12608000074392. 2011 Gattellari et al; licensee BioMed Central Ltd

Catheter Ablation for Atrial Fibrillation: Predicting Recurrence

Background Catheter ablation has emerged as treatment for atrial fibrillation (AF). Health care-related variables have not been explored as predictors of first ablation outcome. Determining factors associated with arrhythmia recurrence may help select patients likely to benefit. The objective was to identify variables associated with recurrence following AF ablation. Methods Retrospective cohort design of 314 AF patients who had undergone first ablation. Follow-up visits occurred at 3, 6 and 12 months. Variables and the outcome of recurrence were modeled with Cox proportional hazards analysis. Results/Conclusions After mean follow-up of 239+/-125 days, 110/314 patients (35.0%) experienced recurrence. Adjusted Cox proportional hazards models demonstrated cardiomyopathy [HR (95% CI) = 1.97 (1.13-3.41)] was associated with arrhythmia recurrence. Conversely, height per cm increase [HR (95% CI) = 0.96 (0.94-0.99)], and targeted ablation outside the pulmonary veins [HR (95% CI) = 0.531 (0.29-0.98)] were associated with hazard reduction. Wait time was not associated with recurrence