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

Abstract

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.

Detection of Premature Ventricular Contractions on a Ventricular Electrocardiogram for Patients With Left Ventricular Assist Devices

“…The v-ECG has generally been used for measuring the HR and has not been used for assessing heart irregularities (20)(21)(22). HR measurement can be used for the detection of ventricular tachycardia (VT) and ventricular fibrillation (VF), in which the HR changes dramatically.…”

“…These additional devices and lead wires severely burden LVAD patients, who are already required to carry an external controller and batteries (17). To enable patients to move freely and to eliminate the various external noise and motion artifacts, ECG electrodes and wires may be substituted with implantable electrodes and wires set on ventricular muscle (20)(21)(22). The ventricular electrocardiogram (v-ECG) is obtained through one or several electrodes directly located on the ventricular muscle and has been applied in patients with pacemakers, ICDs, and LVADs with high reliability.…”

“…The ventricular electrocardiogram (v-ECG) is obtained through one or several electrodes directly located on the ventricular muscle and has been applied in patients with pacemakers, ICDs, and LVADs with high reliability. However, the v-ECG has a different waveform from the conventional ECG and needs to be studied carefully to accurately analyze the heart's condition (22).…”