|Modes of Operation||Timing of Support||Indication(s) for Use|
|Volume displacement pumps||Asynchronous||Rate of VAD is fixed and asynchronous to native QRS complex||Initiation of mechanical support, weaning from device, and during times of hemodynamic instability|
|Volume or automatic⁎||Asynchronous from native QRS complex, pumping is adjusted passively according to the left ventricular filling volume||Outpatient routine operation, exercise|
|External synchronous⁎||Synchronized to native QRS complex||Weaning from device|
|Rotary blood pumps||Fixed rate||Constant pump speed (rotations/min)||Initiation of mechanical support, weaning from device|
|Variable rate||Speed of pump adjusts to the activity level of patient and cardiac contractility||Outpatient routine operation, exercise|
VAD = ventricular assist device.
↵⁎ A backup device rate is needed when placing patients in either volume or external asynchronous modes of support. Backup rates are typically pre-set at 50 to 60 beats/min.