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Updated: Oct 4, 2026
Implantation of Left Ventricular Assist Device (LVAD) in Juvenile Landrace Swine: A LVAD Implantation Model of Pediatric Heart Failure
Published on: January 16, 2026
Physiologic analysis of cardiac cycle in an implantable impeller centrifugal left ventricular assist device
1Department of Surgery, National Taiwan University, Taipei, Taiwan, Republic of China.
Insights
This study investigated the relationship between the cardiac cycle and the Taita No.1 left ventricular assist device (T-LVAD). Optimal T-LVAD control was achieved at 14V, enhancing physiologic effectiveness during the cardiac cycle.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Medical Devices
Background:
- Left ventricular assist devices (LVADs) are crucial for managing heart failure.
- Understanding the interaction between LVADs and the native cardiac cycle is vital for optimizing device performance and patient outcomes.
- Nonpulsatile centrifugal LVADs require careful control to synchronize with physiological heart rhythms.
Purpose of the Study:
- To determine the physiologic relationship between the cardiac cycle and the Taita No.1 left ventricular assist device (T-LVAD).
- To evaluate the impact of variable pump control voltages on T-LVAD flow during different phases of the cardiac cycle.
- To identify optimal control parameters for physiologically effective T-LVAD function.
Main Methods:
- A chronic animal study was conducted using 2 healthy calves implanted with the T-LVAD.
- The T-LVAD was surgically implanted connecting the left ventricle to the aorta.
- Measurements included electrocardiogram, outflow pressure, T-LVAD flow, and speed, analyzed across four defined cardiac cycle stages at varying voltages (10-18V).
Main Results:
- The sensing current of the T-LVAD was inversely related to pump speed within a cardiac cycle.
- T-LVAD flow varied across the four cardiac cycle stages.
- The highest flow ratio (MVC-AVC/AVC-MVC) was observed when the T-LVAD operated at 14V.
Conclusions:
- The study successfully elucidated the physiologic relationship between the cardiac cycle and the T-LVAD.
- Analysis of the flow ratio during the cardiac cycle provides a method for optimizing T-LVAD control.
- A control voltage of 14V appears to yield the most physiologically effective performance for the T-LVAD in this model.
Abstract:
The purpose of this study was to determine the physiologic relationship between the cardiac cycle and the nonpulsatile impeller centrifugal Taita No.1 left ventricular assist device (T-LVAD) in a chronic animal study. The relationship of the cardiac cycle, pump flow, aortic pressure, left ventricle pressure, and pump power were analyzed by 5 phases in 4 stages. The isovolumetric ventricular phase is from mitral valve closure (MVC) to aortic valve opening (AVO) and is called Stage 1. The ejection phase is from AVO to aortic valve closure (AVC) and is called Stage 2. The isovolumetric relaxation phase is from AVC to MVC and is called Stage 3. The passive filling and atrial contraction phase is from MVC to mitral valve opening (MVO) and called Stage 4. Based on evidence from the physiologic volume change of the left ventricle, the change of pump flow of the T-LVAD in a cardiac cycle by variable voltages of pump control was evaluated using animal models. After left posteriolateral thoracotomy via the fifth intercostal space under general anesthesia, the nonpulsatile centrifugal T-LVAD was implanted into 2 healthy calves. The inflow of the T-LVAD was inserted into the left ventricle through the mitral valve via the left atrial appendage. The arterial blood pressure waveform was measured and recorded on the outflow of the T-LVAD. The 4 phases of a cardiac cycle were defined as MVC-AVO (Stage 1), AVO-AVC (Stage 2), AVC-MVO (Stage 3) and MVC-MVO (Stage 4) according to the outflow pressure of the outflow of the T-LVAD and differential pressure between the outflow and inflow of the T-LVAD. We carried out the real-time waveform measurement for electrocardiogram, the outflow pressure, the T-LVAD flow and the speed, as well as open loop and constant voltage (V). In a cardiac cycle, the sensing current of the T-LVAD was inverse to the speed. The flow of the T-LVAD at the 4 stages was measured individually and analyzed with different control voltages from 10 to 18 V. The highest flow ratio of MVC-AVC/AVC-MVC was noted when the T-LVAD worked on 14 V. By using analysis methodology of the flow ratio of a cardiac cycle, the optimal physiologically effective control of the T-LVAD might be achieved.
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