A monitoring device, comprising: an input block configured to obtain a first pressure signal (p6a-p6d) from a first pressure sensor (6a-6d), which is arranged in an extracorporeal blood processing apparatus to detect pressure variations in a fluid which is pumped through a blood processing unit in the extracorporeal blood processing apparatus, wherein the extracorporeal blood processing apparatus is connected to a vascular system of a subject and comprises at least one blood pumping device (4, 46) operable to pump blood from the vascular system through the blood processing unit and back to the vascular system; a processing block configured to repeatedly process the first pressure signal (p6a-p6d) for generation of a time- sequence of parameter values indicative of pressure pulsations originating from heartbeats in the subject; and an evaluation block configured to evaluate the parameter values according to a detection criterion for cardiac arrest, which is set to detect a disappearance of the pressure pulsations originating from the heartbeats in the first pressure signal (p6a-p6d), and, if the detection criterion is fulfilled, generate an alarm signal that signals a cardiac arrest in the subject, wherein the input block is further configured to obtain a second pressure signal (p6a-p6d) from a second pressure sensor (6a-6d), which is arranged in the extracorporeal blood processing apparatus to detect pressure variations in the fluid; wherein the processing block is configured to process the first and the second pressure signals (p6a-p6d) for generation of the time- sequence of parameter values, and wherein the detection criterion for cardiac arrest is set to detect a disappearance of the pressure pulsations originating from the heartbeats in both of the first and second pressure signals (p6a-p6d). an input block configured to obtain a first pressure signal (p6a-p6d) from a first pressure sensor (6a-6d), which is arranged in an extracorporeal blood processing apparatus to detect pressure variations in a fluid which is pumped through a blood processing unit in the extracorporeal blood processing apparatus, wherein the extracorporeal blood processing apparatus is connected to a vascular system of a subject and comprises at least one blood pumping device (4, 46) operable to pump blood from the vascular system through the blood processing unit and back to the vascular system; a processing block configured to repeatedly process the first pressure signal (p6a-p6d) for generation of a time- sequence of parameter values indicative of pressure pulsations originating from heartbeats in the subject; and an evaluation block configured to evaluate the parameter values according to a detection criterion for cardiac arrest, which is set to detect a disappearance of the pressure pulsations originating from the heartbeats in the first pressure signal (p6a-p6d), and, if the detection criterion is fulfilled, generate an alarm signal that signals a cardiac arrest in the subject, wherein the input block is further configured to obtain a second pressure signal (p6a-p6d) from a second pressure sensor (6a-6d), which is arranged in the extracorporeal blood processing apparatus to detect pressure variations in the fluid; wherein the processing block is configured to process the first and the second pressure signals (p6a-p6d) for generation of the time- sequence of parameter values, and wherein the detection criterion for cardiac arrest is set to detect a disappearance of the pressure pulsations originating from the heartbeats in both of the first and second pressure signals (p6a-p6d).