SOD1 and atrioventricular block: Zheng CD et al. [23] found it has cardioprotection against myocardial ischemia/reperfusion (I/R) injury in open heart surgery via significantly improving the systolic blood pressure (SBP), mean blood pressure (MBP), diastolic blood pressure (DBP) values, the recovering rate of spontaneous heart beat, heart rate (HR), electrocardiographic (ECG) ST segment, atrioventricular block, ventricular arrhythmia and superoxide dismutase (SOD), and significantly decreasing the serum concentration of cardiac troponin I (cTnI), malondialdehyde (MDA).