Different circumstances, timing, and symptom presentation at onset of Q-wave versus non–Q-wave acute myocardial infarction

In summary, timing and circumstances of onset, although indirectly, suggest a difference in the importance of triggering mechanisms for the 2 AMI types, supporting the concept of an association of sustained coronary occlusion with Q-wave infarction, and nonsustained occlusion with non-Q-wave infarction. The extent of myocardial damage and patients' preinfarction characteristics can explain much of the difference in symptom presentation and in-hospital prognosis of patients with Q-wave versus non-Q-wave AMI.