Atypical Heart Attack Symptoms May Increase Mortality Risk

Approximately 25% of patients with acute myocardial infarction (MI) have atypical symptoms resulting in delayed emergency medical care and higher rates of morality, according to the result of a recent study.

The researchers examined calls to a 24-hour non-emergency medical helpline and an emergency number in Copenhagen, Denmark. All patients who had been diagnosed with MI at a hospital or as cause of death within 72 hours after making a call were included in the study.

Rates of primary symptoms, including chest pain, atypical symptoms, unconsciousness, non-informative symptoms, and no recorded symptoms were evaluated. Atypical symptoms included breathing problems, unclear problems, central nervous system symptoms, abdominal/back/urinary, other cardiac symptoms, and other atypical symptoms.

Of the 8336 total patients with MI who called either number, 5219 patients had reported chest pain and 556 reported breathing problems.

In patients with chest pain, emergency dispatch was sent in 95% of emergency calls (n = 3337/3508) and 76% (n = 1306/1711) of non-emergency calls. Emergency calls had a 5% (n = 163/3508) mortality rate, while non-emergency calls had a 3% (n = 49/1711) mortality rate. In patients with atypical symptoms, emergency dispatch was sent in 62% (n = 554/900) of emergency calls and 17% (n = 137/813) of non-emergency calls. The mortality rate was 23% (n = 206/900) for emergency calls and 15% (n = 125/813) for non-emergency calls.

Further, for unconscious patients, emergency dispatch was sent in 99% of emergency calls and 100% of non-emergency calls, with a 71% and 75% mortality rate, respectively.

Overall, there was a 4.3% standardized 30-day mortality for chest pain and a 15.6% morality for atypical symptoms. The relationships between symptoms and emergency dispatch were consistent despite age and sex subgroups.

“Myocardial infarction patients presenting with atypical symptoms when calling for help have a reduced chance of receiving emergency dispatch and increased 30-day mortality compared to MI patients with chest pain,” the researchers concluded. 

—Leigh Precopio

Reference:

Møller AL, Mills EHA, Gnesin F, et al. Impact of myocardial infarction symptom presentation on emergency response and survival. European Heart Journal. Published online May 5, 2021. https://doi.org/10.1093/ehjacc/zuab023