REN and cardiac arrhythmia: For example, inflammation-causing fibrosis and hypertrophy activate cardiac fibroblasts, nonexcitable cells that can conduct electrical currents.53 This causes the depolarization of myocytes, resulting in arrhythmias.54 In addition, activation of the renin-angiotensin-aldosterone system (RAAS) upon kidney damage results in the retention of large amounts of sodium and water and, thus, volume overload.55 As described above, this causes structural changes, that is, fibrosis and hypertrophy, resulting in arrhythmias.