| Final 17:40 | Team | time | | L | React. | Bib | | 1. Yenifer Padilla | COL | 51.53s | PB | 6 | 0.253 | 92 | | 2. Daysiurami Bonne | CUB | 51.69s | PB | 5 | 0.542 | 101 | | 3. Geisa Coutinho | BRA | 51.87s | | 2 | 0.204 | 32 | | 4. Aymee Martinez | CUB | 52.09s | | 3 | 0.402 | 115 | | 5. Norma Gonzalez | COL | 52.18s | | 4 | 0.246 | 81 | | 6. Joelma Sousa | BRA | 52.34s | | 7 | 0.340 | 58 | | 7. Patricia Hall | JAM | 52.69s | | 8 | 0.241 | 170 | | 8. Raysa Melany Sanchez Alvarez | DOM | 52.86s | | 1 | 0.263 | 138 |
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| World Record: | | Marita Koch (GDR) 47.60s | | Canberra (AUS) 06.10.1985 | | Panamerican Record: | | Ana Fidelia Quirot (CUB) 49.61s | | La Habana (CUB) 05.08.1991 |
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| Heats - Tuesday 25.10 - First 3 and Best 2 progress. |
| Heat 1 16:15 | Team | time | | L | React. | Bib | | 1. Norma Gonzalez | COL | 52.67s | | 6 | 0.206 | 81 | | 2. Aymee Martinez | CUB | 52.76s | | 2 | 0.295 | 115 | | 3. Joelma Sousa | BRA | 52.96s | | 8 | 0.253 | 58 | | 4. Raysa Melany Sanchez Alvarez | DOM | 53.08s | | 3 | 0.245 | 138 | | 5. Nallely Vela | MEX | 53.29s | | 7 | 0.263 | 206 | | 6. Christian Evelyn Brennan | CAN | 53.34s | | 5 | 0.178 | 60 | | 7. Leslie Eugenia Cole | MEX | 53.38s | | 4 | 0.131 | 249 |
| Heat 2 16:22 | Team | time | | L | React. | Bib | | 1. Yenifer Padilla | COL | 51.76s | | 3 | 0.169 | 92 | | 2. Daysiurami Bonne | CUB | 52.20s | | 5 | 0.221 | 101 | | 3. Patricia Hall | JAM | 52.47s | | 6 | 0.144 | 170 | | 4. Geisa Coutinho | BRA | 52.56s | | 2 | 0.179 | 32 | | 5. Kineke Alexander | VIN | 53.42s | SB | 8 | 0.245 | 290 | | 6. Jessica Cousins | USA | 54.38s | | 4 | 0.252 | 251 | | 7. Kanika Alana Beckles | GRN | 56.43s | | 7 | 0.200 | 153 |
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