Background and Purpose Electrocardiographic (ECG) left atrial abnormality has been associated with stroke independently of atrial fibrillation (AF), suggesting that atrial thromboembolism may occur in the absence of AF. If true, we would expect an association with cryptogenic or cardioembolic stroke rather than non-cardioembolic stroke. Methods We conducted a case-cohort analysis in the Northern Manhattan Study, a prospective cohort study of stroke risk factors. P-wave terminal force in lead V1 (PTFV1) was manually measured from baseline ECGs of participants in sinus rhythm who subsequently had ischemic stroke (N = 241) and a randomly selected subcohort without stroke (N = 798). Weighted Cox proportional hazards models were used to examine the association between PTFV1 and stroke etiological subtypes while adjusting for baseline demographic characteristics, history of AF, heart failure, diabetes, hypertension, tobacco use, and lipid levels. Results Mean PTFV1 was 4,452 (±3,368) μV*ms among stroke cases and 3,934 (±2,541) μV*ms in the subcohort. PTFV1 was associated with ischemic stroke (adjusted hazard ratio [HR] per standard deviation [SD], 1.20; 95% confidence interval [CI], 1.03-1.39) and the composite of cryptogenic or cardioembolic stroke (adjusted HR per SD, 1.31; 95% CI, 1.08-1.58). There was no definite association with non-cardioembolic stroke subtypes (adjusted HR per SD, 1.14; 95% CI, 0.92-1.40). Results were similar after excluding participants with a history of AF at baseline or new AF during follow-up. Conclusions ECG-defined left atrial abnormality was associated with incident cryptogenic or cardioembolic stroke independently of the presence of AF, suggesting atrial thromboembolism may occur without recognized AF.
Background Medical student education in the era of the COVID-19 outbreak is vastly different than the standard education we have become accustomed to. Medical student assessment is an important aspect of adjusting curriculums in the era of increased virtual learning. Methods Students took our previously validated free response clinical skills exam (CSE) at the end of the scheduled clerkship as an open-book exam to eliminate any concern for breaches in the honor code and then grades were adjusted based on historic norms. The National Board of Medical Examiners (NBME) shelf exam was taken with a virtual proctor. Students whose clerkship was affected by the COVID-19 pandemic were compared to the students from a similarly timed surgery block the previous 3 years. Primary outcomes included CSE and NBME exam scores. Secondary outcomes included clinical evaluations and the percentage of students who received grades of Honors, High Pass, and Pass. After the surgery clerkship was completed, we surveyed all students who participated in the surgery clerkship during the COVID-19 crisis. Results There were 19 students during the COVID-interrupted clerkship and 61 students in similarly timed clerkships between 2017 and 2019. Prior to adjustment and compared to historic scores, the COVID-interrupted clerkship group scored higher on the CSE, NBME exam, and performance evaluations (median, CSE:75.2 vs 68.7, shelf:68.0 vs 64.0, performance evaluation mean: 2.96 vs 2.78). The percentage of students with an honors was marginally higher in the group affected by COVID (42% vs 32%). Out of 19 students surveyed, 9 students responded. Seven students stated they would have preferred a closed-book CSE, citing a few drawbacks of the open-book format such as modifying their exam preparation, being discouraged from thinking prior to searching online during the test, and second guessing their answers. Conclusions During the initial outbreak of COVID-19, we found that an open book exam and a virtually proctored shelf exam was a reasonable option. However, to avoid adjustments and student dissatisfaction, we would recommend virtual proctoring if available.
Background Mobile stroke units ( MSU s) reduce time to intravenous thrombolysis in acute ischemic stroke. Whether this advantage exists in densely populated urban areas with many proximate hospitals is unclear. Methods and Results We evaluated patients from the METRONOME (Metropolitan New York Mobile Stroke) registry with suspected acute ischemic stroke who were transported by a bi‐institutional MSU operating in Manhattan, New York, from October 2016 to September 2017. The comparison group included patients transported to our hospitals via conventional ambulance for acute ischemic stroke during the same hours of MSU operation (Monday to Friday, 9 am to 5 pm) . Our exposure was MSU care, and our primary outcome was dispatch‐to‐thrombolysis time. We estimated mean differences in the primary outcome between both groups, adjusting for clinical, demographic, and geographic factors, including numbers of nearby designated stroke centers and population density. We identified 66 patients treated or transported by MSU and 19 patients transported by conventional ambulance. Patients receiving MSU care had significantly shorter dispatch‐to‐thrombolysis time than patients receiving conventional care (mean: 61.2 versus 91.6 minutes; P =0.001). Compared with patients receiving conventional care, patients receiving MSU care were significantly more likely to be picked up closer to a higher mean number of designated stroke centers in a 2.0‐mile radius (4.8 versus 2.7, P =0.002). In multivariable analysis, MSU care was associated with a mean decrease in dispatch‐to‐thrombolysis time of 29.7 minutes (95% CI , 6.9–52.5) compared with conventional care. Conclusions In a densely populated urban area with a high number of intermediary stroke centers, MSU care was associated with substantially quicker time to thrombolysis compared with conventional ambulance care.
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