The general definition has been expanded into five subtypes reflecting the primacy of organ dysfunction and the time-frame of the syndrome: CRS type 1 = acute worsening of heart function leading to kidney injury and/or dysfunction; CRS type 2 = chronic abnormalities in heart function leading to kidney injury or dysfunction; CRS type 3 = acute worsening of kidney function leading to heart injury and/or dysfunction; CRS type 4 = chronic kidney disease leading to heart injury, disease and/or dysfunction, and CRS type 5 = systemic conditions leading to simultaneous injury and/or dysfunction of heart and kidney.