Table 1.
Demographic and Clinical Characteristics of Study Sample
| Symptom Onset to 9-1-1 Call | |||
|---|---|---|---|
| Characteristic | All Patients (n = 743) | 0–12 h (n = 565 [76%]) | > 12 h (n = 178 [24%]) |
| Sociodemographic characteristics | |||
| Age, years, median (IQR) | 72 (23) | 58 (24) | 56 (23) |
| Sex (male), n (%) | 427 (57) | 325 (58) | 102 (57) |
| Income class, n (%) | |||
| Low | 583 (79) | 441 (78) | 136 (76) |
| Middle | 154 (21) | 115 (20) | 38 (21) |
| Race, n (%) | |||
| Caucasian | 434 (58) | 338 (60) | 90 (51) |
| Black | 301 (40) | 219 (39) | 81 (45) |
| Other | 15 (2) | 8 (1) | 7 (4) |
| EMS factors | |||
| Day of event, n (%) | |||
| Weekday | 508 (68) | 382 (68) | 126 (71) |
| Weekend | 235 (32) | 183 (32) | 52 (29) |
| Time of event, n (%) | |||
| 12:00 am–6:00 am | 123 (17) | 96 (17) | 27 (15) |
| 6:00 am–12:00 pm | 210 (28) | 158 (28) | 52 (29) |
| 12:00 pm–6:00 pm | 224 (30) | 164 (29) | 60 (34) |
| 6:00 pm–12:00 am | 186 (25) | 147 (26) | 39 (22) |
| Speed of EMS response (9-1-1 call to EMS arrival to scene), min, median (IQR) | 12.1 (11.6–12.5) | 11.8 (11.3–12.0) | 12.9 (11.9–14.0) |
| Duration of transport (EMS arrival to scene to hospital arrival), min, median (IQR) | 33.7 (32.6–34.9) | 33.9 (32.6–35.2) | 32.9 (31.4–34.5) |
| ACS risk factors, n (%) | |||
| Obesity (body mass index > 30) | 285 (38) | 211 (38) | 74 (42) |
| Ever smoked | 434 (58) | 324 (57) | 110 (62) |
| Hypertension | 519 (70) | 398 (71) | 119 (68) |
| Diabetes mellitus | 196 (26) | 142 (25) | 54 (31) |
| Hyperlipidemia | 258 (35) | 196 (35) | 62 (35) |
| Coronary artery disease | 248 (33) | 190 (34) | 58 (33) |
| History of myocardial infarction | 205 (28) | 156 (28) | 49 (28) |
| Known heart failure | 130 (18) | 95 (17) | 35 (20) |
| Prior PCI or CABG | 207 (28) | 159 (28) | 48 (27) |
| Chief complaint, n (%) | |||
| Chest pressure | 642 (87) | 492 (87) | 150 (85) |
| Shortness of breathing | 215 (29) | 165 (29) | 50 (28) |
| Heart rhythm abnormality | 124 (17) | 101 (18) | 23 (13) |
| Atypical symptoms | 53 (7) | 44 (8) | 9 (5) |
| Prehospital vital signs, mean ± SD | |||
| Heart rate (beats/min) | 91 ± 30 | 91 ± 31 | 89 ± 26 |
| Respiratory rate (breaths/min) | 18±4 | 18 ± 3 | 19 ± 7 |
| Systolic blood pressure (mm Hg) | 147 ± 31 | 146 ± 32 | 148 ± 29 |
| Diastolic blood pressure (mm Hg) | 87 ± 19 | 87 ± 19 | 86 ± 19 |
| Oxygen saturation (%) | 97 ± 7 | 98 ± 66 | 97 ± 8 |
ACS = acute coronary syndrome; CABG = coronary artery bypass grafting; EMS = emergency medical services; IQR = interquartile range; PCI = percutaneous coronary intervention.