Reliable trigger of direct cardiac potential for stable drive control of ventricular assist device

A drive control method with direct cardiac potential trigger for a ventricular assist device (VAD) was evaluated in various conditions in an experimental model. A pneumatic VAD was implanted as a support bypass between the left ventricular apex and the ascending aorta in eight animals. The hemodynamic parameters and pump output were monitored. Two tips of a bipolar electrode were set on the RV ( n =3) or on the RV and LV ( n =5) for recording direct cardiac potential. The counter-pulsation drive of the VAD was applied by using the R wave in the standard electrocardiogram (ECG) or the direct cardiac potential as an ECG trigger. As special conditions with various artifacts on the ECG, electromusculogram, arrhythmia, irregular ventilation, and passive vibration (simulation of exercise) were set for assessing the ECG trigger modes. Artifacts of irregular ventilation and passive vibration made the drive control poor under standard ECG trigger and caused incomplete control in the case of direct cardiac potential trigger by using the RV bipolar electrode. In contrast, direct cardiac potential trigger by using the RV and LV bipolar electrode maintained the counter-pulsation control of the VAD well in all conditions of this study. The results suggest that this counter-pulsation control with direct cardiac potential trigger might be one of the control methods for various VADs of the next generation.