When fainting signals a bigger problem

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A simple nine-question tool could help emergency physicians uncover the dangerous hidden conditions that make some people faint, according to a Canadian study,

Fainting is fairly common – 35% to 40% of people faint at least once in their lives. But for about 10% of people who visit the emergency room for fainting it can be a symptom of a potentially life-threatening condition like arrhythmia, or heart rhythm disturbance.

A team of researchers at The Ottawa Hospital and the University of Ottawa have created a screening tool to help emergency doctors predict the risk of a patient experiencing adverse events from these hidden conditions within a month of fainting. These include irregular heartbeat, heart attacks and even death. If the risk is high, then doctors would do a thorough evaluation in the hospital before sending the patient home.

“Fainting is a big problem,” said Dr Venkatesh Thiruganasambandamoorthy, an emergency physician and scientist at The Ottawa Hospital and an assistant professor at the University of Ottawa. “The way fainting patients are examined in emergency rooms varies greatly between physicians and hospitals. We hope that this screening tool will make the process more consistent and improve the detection of serious conditions related to fainting.”

Thiruganasambandamoorthy also notes that most fainting patients admitted to hospital do not need to be there. These patients can spend four to seven hours in the emergency department before a decision to discharge them is made. “If our tool can discharge low-risk patients quickly and safely, then I think we can reduce emergency room wait times and open up those resources to other patients,” he said.

Of the 4,030 fainting patients his team observed across six Canadian emergency rooms, 147 suffered a serious event in the month after discharge. This is largest study of its kind in the world.

After following up with patients and analysing clinical findings from emergency doctors, Dr Thiruganasambandamoorthy and his team found nine factors that physicians can plug into a screening tool. Added together, these factors give the patient’s total risk of an adverse event, from very low to very high.

These factors include: the physician’s diagnosis of the cause of fainting; signs of a common and harmless variety of fainting, such as being in a warm or crowded place, standing for a long time, or feeling intense fear, emotion or pain; a history of heart disease; abnormal electrocardiogram (ECG) measurements; and higher levels of troponin, a protein specific to heart muscle.

This study was funded by Physicians Services Incorporated Foundation, Canadian Institutes of Health Research, Ontario Innovation Fund and The Ottawa Hospital Foundation.

The tool is currently being validated in emergency rooms across Canada in a study funded by the Canadian Arrhythmia Network. Once validation is complete, Thiruganasambandamoorthy hopes to make the tool available online and as an app.

Background: Syncope can be caused by serious conditions not evident during initial evaluation, which can lead to serious adverse events, including death, after disposition from the emergency department. We sought to develop a clinical decision tool to identify adult patients with syncope who are at risk of a serious adverse event within 30 days after disposition from the emergency department.
Methods: We prospectively enrolled adults (age ≥ 16 yr) with syncope who presented within 24 hours after the event to 1 of 6 large emergency departments from Sept. 29, 2010, to Feb. 27, 2014. We collected standardized variables at index presentation from clinical evaluation and investigations. Adjudicated serious adverse events included death, myocardial infarction, arrhythmia, structural heart disease, pulmonary embolism, serious hemorrhage and procedural interventions within 30 days.
Results: We enrolled 4030 patients with syncope; the mean age was 53.6 years, 55.5% were women, and 9.5% were admitted to hospital. Serious adverse events occurred in 147 (3.6%) of the patients within 30 days after disposition from the emergency department. Of 43 candidate predictors examined, we included 9 in the final model: predisposition to vasovagal syncope, heart disease, any systolic pressure reading in the emergency department < 90 or > 180 mm Hg, troponin level above 99th percentile for the normal population, abnormal QRS axis (< −30° or > 100°), QRS duration longer than 130 ms, QTc interval longer than 480 ms, emergency department diagnosis of cardiac syncope and emergency department diagnosis of vasovagal syncope (C statistic 0.88, 95% confidence interval [CI] 0.85-0.90; optimism 0.015; goodness-of-fit p = 0.11). The risk of a serious adverse event within 30 days ranged from 0.4% for a score of −3 to 83.6% for a score of 11. The sensitivity was 99.2% (95% CI 95.9%-100%) for a threshold score of −2 or higher and 97.7% (95% CI 93.5%-99.5%) for a threshold score of −1 or higher.
Interpretation: The Canadian Syncope Risk Score showed good discrimination and calibration for 30-day risk of serious adverse events after disposition from the emergency department. Once validated, the tool will be able to accurately stratify the risk of serious adverse events among patients presenting with syncope, including those at low risk who can be discharged home quickly.

Venkatesh Thiruganasambandamoorthy, Kenneth Kwong, George A Wells, Marco LA Sivilotti, Muhammad Mukarram, Brian H Rowe, Eddy Lang, Jeffrey J Perry, Robert Sheldon, Ian G Stiell, Monica Taljaard

The Ottawa Hospital material
Canadian Medical Association Journal abstract

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