Atypical MI symptoms tied to negative outcomes, lower odds of emergency response
Patients with atypical MI symptoms were less likely to receive emergency help and had greater risk for dying within 30 days compared with those with chest pain, researchers reported.
“We found that atypical symptoms were most common among older people, especially women, who called a nonemergency helpline for assistance. This suggests that patients were unaware that their symptoms required urgent attention,” Amalie Lykkemark Møller, a PhD student at Nordsjællands Hospital in Hillerød, Denmark, said in a press release.
Researchers in Denmark examined the link between initial MI symptoms, the medical service response and 30-day mortality. The cohort included 4,880 patients with MI who made an emergency call and 3,456 patients with MI who made a nonemergency call from 2014 to 2018.
According to the researchers, among patients with MI, chest pain was the most common symptom (72%), whereas 24% of the cohort had atypical symptoms, including breathing problems, central nervous system symptoms, abdominal/back/urinary problems, unclear problems and other cardiac symptoms. In the overall cohort, the most common atypical symptom was breathing problems (8%).
The researchers found that the prevalence of chest pain was highest in men aged 30 to 59 years who called the emergency number (85%) and lowest in women older than 79 years who called the nonemergency helpline (49%).
Among patients with chest pain, 95% of those who called the emergency number and 76% of those who called the nonemergency helpline received emergency dispatch, according to the researchers.
Among patients with atypical symptoms, the percentage receiving an emergency dispatch was 62% among those who called the emergency number and 17% among those who called the nonemergency helpline, Møller and colleagues wrote, noting an ambulance was three times more likely to attend to patients experiencing chest pain than those with other symptoms.
The 30-day mortality rate for patients with MI and chest pain was 5% among those who called the emergency number and 3% among those who called the nonemergency helpline.
Rates were higher among patients with MI atypical symptoms: 23% and 15% died within 30 days after calling the emergency number and nonemergency helpline, respectively, according to the researchers.
The researchers determined that the standardized 30-day mortality rate was 4.3% for patients with chest pain and 15.6% for those with atypical symptoms.
People with atypical symptoms were more inclined to call the helpline, which could suggest that their symptoms were milder or they were not aware of the severity, according to the researchers.
“Death within 30 days was more than threefold higher in those with atypical symptoms compared to chest pain. This could be due to treatment delays caused by not receiving the appropriate emergency dispatch. However, it is unknown whether an increase in emergency dispatches alone would improve survival among MI patients with atypical symptoms — we aim to investigate this in future research projects,” Møller said in the release.