TNNI3 and cardiac arrest: Our observations are also consistent with animal models demonstrating that after the onset of myocardial ischemia, cell death is not immediate but takes a finite period to develop: it has been reported that the level of cardiac troponins I (cTnI) starts to increase by 30 min with a peak value at 3 h after cardiac arrest in adult pigs30 and 4 h of hypoxia in rats has no effect on coronary flow rate or cardiac troponin T31.