b'2024 DATASETINITIAL RHYTHMUpon initial cardiac rhythm monitoring following OHCA, a patient may present in either a shockable rhythm (ventricular fibrillation or ventricular tachycardia) or non-shockable rhythm (asystole or idioventricular/pulseless electrical activity [PEA]). Treatment and prognosis depend on presenting rhythm, with significantly better survival rates among patients presenting with a shockable rhythm compared to those with a non-shockable rhythm (29.3% vs 6.5%, p.0001).18.1% of patients presented with an initial shockable rhythm of ventricular fibrillation (VF) or ventricular tachycardia (VT), while 81.9% of patients presented in an unshockable rhythm, with asystole being the most common (50.6%). The presenting rhythm differed markedly by arrest witness status, with bystander witnessed patients being much more likely to present in a shockable rhythm compared to unwitnessed patients (28.8% vs 10.2%, respectively; p.0001) (Figure 9).Figure 9. Presenting arrest rhythm by arrest witness status.36 City of Miami Fire Rescue reunited with a cardiac arrest survivor and his familycelebrating the power of fast response and teamwork.'