Research finds standard medical tests do not adequately diagnose most heart attacks

Recent findings regarding unrecognized heart attacks (myocardial infarction; MI) have renewed concerns about the accuracy of standard medical tests routinely administered by hospitals and doctors. Researchers came about this discovery while looking into the long-term outlook of unrecognized MI cases; their results were published in the European Society of Cardiology (ESC).

• A community of 935 Icelanders served as subjects. All participants underwent electrocardiographic imaging (ECG) and cardiovascular magnetic resonance (CMR) imaging. Based on the results, researchers categorized the participants into three groups: recognized myocardial infarctions (clinical events that could be diagnosed by standard medical tests), unrecognized MI (sub-clinical events only detectable by ECG and CMR), and no MI (verified by CMR).
• The researchers recorded that 91 participants (10 percent) were recognized MI cases. Meanwhile, 156 individuals (17 percent) tested positive for unrecognized MI. The last group of 688 members (74 percent of the entire group) received clean bills of cardiac health.
• The study revealed that 156 out of 247 of the myocardial infarctions identified by CMR were unrecognized MI. That translates to 63 percent of the total MI cases that would escape diagnosis by routine medical care.
• At five years, the mortality rate of patients with unrecognized MI (13 percent) was lower than those with recognized MI (19 percent) but higher than patients with no MI (8 percent). At ten years, the mortality rate of patients with unrecognized MI (49 percent) approached that of recognized MI patients (51 percent) and exceeded those with no MI (30 percent).
• The findings suggest there might be more cases of unrecognized MI than there are of recognized MI. Furthermore, the mortality rate of patients with sub-clinical MI has been shown to increase over time until it matches the mortality rate of patients with diagnosed heart attacks.

Researchers recommended shifting a proportion of cardiac evaluation from traditional tests to CMR imaging for early and accurate diagnosis of unrecognized MI patients.