Dear Dr. B: Your last column discussed the symptoms of heart attack and immediate actions required to increase survival if one was having chest pain. What I would like to know is how often an ER physician would miss a diagnosis of a heart attack?
ER physicians are not infallible. The diagnosis of a heart attack can be missed. How often does this happen? This subject is well covered in an article published in the recent issue of the Canadian Medical Association Journal (CMAJ). Here is the summary of the article.
Approximately half a million people present to Canadian emergency department s with chest pain. About 62,000 Canadians are admitted to hospital with acute heart attack. Probably an equal number are admitted with unstable angina.
There are good assessment protocols for ER physicians to use in patients with chest pain but none helps clinicians determine which patients can safely be discharged from the emergency department after a brief assessment, says the CMAJ article.
U.S. studies have shown that approximately two percent of patients are discharged home where the diagnoses of a heart attack has been missed.
The authors of the CMAJ article studied 1819 patients at St. Pauls and Vancouver General hospitals. The mean age of the patient was 58 years. Fifty eight percent of the patients were males. Thirty one percent of the patients arrived to the department by ambulance.
Twenty two percent (398 out of 1819) of patients had a diagnosis of acute heart attack or unstable angina on admission or confirmed within 30 days. Unfortunately, five percent of patients had been discharged from the emergency department because the diagnosis was missed.
The authors of the article indicate that the number of missed diagnoses in Canadian ER is higher than in U.S. where a study found the rate of missed diagnoses around two percent. The authors feel that the existing diagnostic pathways and guidelines do not include clear guidance for the early discharge of patients with chest pain.
The authors conclude that opportunities exist to improve both safety and efficiency by developing clinical tools to help clinicians identify patients who can safely be discharged after a short period of investigation. Ideally, the rate of missed diagnosis should not be more than two percent.
The study shows that if a patient presents with chest pain or discomfort to an emergency department in a Canadian hospital then 95 percent of the time you will have an appropriate diagnosis and treated accordingly. As better diagnostic tools become available the number of patients discharged with a missed diagnose will be much less.
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