Background and aims – Rapid reperfusion is crucial to reduce mortality in patients with ST-elevation myocardial infarction (STEMI). Prehospital patient delay, defined as time from symptoms onset to the decision to seek medical attention, accounts for a large proportion of cases with delayed reperfusion. However, whether altered pain modulation processes affect less severe pain symptoms and consequentely prolonger delay needs further illumination.  We explored whether prehospital patient delay is affected by a reduction of perceived pain perception and pain modulation response. 
Methods – the facilitatory and inhibitory pain modulation pathways assessed by psychophysical tests of temporal summation and conditioned pain modulation (CPM) as well as sensation and pain thresholds, magnitude estimation of supra-threshold stimulation. Pain recalls at the onset of chest pain were obtained in 67 STEMI hospitalized patients. The associations between these measures and chest pain intensity and duration of patient delay were explored.
Results - Among all psychophysical pain measures only warm sensation threshold was independently associated with lower clinical chest pain intensity (p = 0.01). Multivariable regression analysis (R2 = 0.449; P <0.0001) revealed an inverse independent association between chest pain intensity (P<0.001) and patient delay whereas efficient CPM was positively associated with prolonged patient delay (P = 0.034). The electrocardiography-derived myocardial ischemic area at risk for necrosis was not associated with chest pain intensity or patient delay. 
Discussion - Beyond the perceived chest pain intensity, patients who exhibit efficient response of the descending inhibition pathways have prolonged delay in seeking medical help after the onset of chest pain during acute coronary occlusion. These findings may serve in the future to identify patients prone to experience less pain and therefore to feel less hazard as expressed by delay in seeking medical help.

Pain modulation prodile prdict patient delay in seeking medical help in acute myocardial infarction