Causes of Pre-Hospital Delay in Patients with Acute Myocardial Infarction

Objective: To determine the factors influencing the delay in presentation of symptomatic patients of acute myocardial infarction at hospital emergency department. Study Design: An observational study. Place and Duration of Study: Department of Medicine, Mayo Hospital, King Edward Medical University, Lahore, from June, 2010 to June 2011. Methodology: 300 patients were included in the study with the following criteria: symptomatic myocardial infarction uncomplicated by cardiac arrest, age less than 70 years and presentation less than 24 hours after onset of chest pain. Myocardial infarction was defined as history of characteristic chest pain with either an ECG showing standard changes of myocardial infarction, and / or a rise in cardiac markers of more than double the upper normal range. After informed consent, the following data was collected from the subjects and entered in a structured proforma: patient demographics, previous cardiac and medical history, duration of delay, type of delay, the reason for the delay and the first response of the patient. SPSS 19 was used to analyze the data and the results were described in term of descriptive statistics. Results: Amongst the total of 300 patients, 234 (78%) were males and 66 (22%) were females. Age ranged between 31 – 66 years. 204 (68%) had no previous cardiac history, 24 (8%) had suffered from angina alone and 72 (24 %) had been diagnosed to have had MI previously. One hundred fifty six (52%) were hypertensive, 72 (24%) were diabetic, 66 (22%) had both hypertension and diabetes mellitus. Twenty four (8%) had previously suffered from a cerebrovascular accident, 12 (4%) were having hyperlipidemia and 6 (2%) had an underlying vasculitic disorder. 174 (58%) had delayed decision time, while 120 (40%) had delayed response time; only 6 (2%) presented within ½ hour of chest pain. The commonest reason (70%) for patient’s delay in presentation was that they thought it was not serious and would settle on its own. Maximum number of those having chest pain (44%) presented directly to the hospital emergency. Conclusion: Factors including patient’s demographic, past medical history, clinical presentation, recognition of symptoms, and the first contact approached for help affect the duration of prehospital delay in patients with acute myocardial infarction.