Validation of Cardiac Output as Reported by a Permanently Implanted Wireless Sensor

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
Michael Tree ◽  
Jason White ◽  
Prem Midha ◽  
Samantha Kiblinger ◽  
Ajit Yoganathan
Keyword(s):  
Heart Failure ◽  
Cardiac Output ◽  
Measurement Accuracy ◽  
Circulatory System ◽  
Left Heart Failure ◽  
Mock Circulatory System ◽  
System A ◽  
Reference Flow ◽  
Relevant Range

The CardioMEMS heart failure (HF) system was tested for cardiac output (CO) measurement accuracy using an in vitro mock circulatory system. A software algorithm calculates CO based on analysis of the pressure waveform as measured from the pulmonary artery, where the CardioMEMS system resides. Calculated CO was compared to that from reference flow probe in the circulatory system model. CO measurements were compared over a clinically relevant range of stroke volumes and heart rates with normal, pulmonary hypertension (PH), decompensated left heart failure (DLHF), and combined DHLF + PH hemodynamic conditions. The CardioMEMS CO exhibited minimal fixed and proportional bias.

scholarly journals In vitro study of trileaflet polytetrafluoroethylene conduit and its valve-in-valve transformation

2020 ◽  
Vol 30 (3) ◽  
pp. 408-416 ◽  
Author(s):  
Te-I Chang ◽  
Kang-Hong Hsu ◽  
Chi-Wen Luo ◽  
Jen-Hong Yen ◽  
Po-Chien Lu ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Stent Graft ◽  
Peak Pressure ◽  
Circulatory System ◽  
Valve Design ◽  
Mock Circulatory System ◽  
Valved Conduit ◽  
Valve In Valve ◽  
In Vitro Performance

Abstract OBJECTIVES Handmade trileaflet expanded polytetrafluoroethylene valved conduit developed using the flip-over method has been tailored for pulmonary valve reconstruction with satisfactory outcomes. We investigated the in vitro performance of the valve design in a mock circulatory system with various conduit sizes. In our study, the design was transformed into a transcatheter stent graft system which could fit in original valved conduits in a valve-in-valve fashion. METHODS Five different sizes of valved polytetrafluoroethylene vascular grafts (16, 18, 20, 22 and 24 mm) were mounted onto a mock circulatory system with a prism window for direct leaflets motion observation. Transvalvular pressure gradients were recorded using pressure transducers. Mean and instant flows were determined via a rotameter and a flowmeter. Similar flip-over trileaflet valve design was then carried out in 3 available stent graft sizes (23, 26 and 28.5 mm, Gore aortic extender), which were deployed inside the valved conduits. RESULTS Peak pressure gradient across 5 different sized graft valves, in their appropriate flow setting (2.0, 2.5 and 5.0 l/min), ranged from 4.7 to 13.2 mmHg. No significant valve regurgitation was noted (regurgitant fraction: 1.6–4.9%) in all valve sizes and combinations. Three sizes of the trileaflet-valved stent grafts were implanted in the 4 sizes of valved conduits except for the 16-mm conduit. Peak pressure gradient increase after valved-stent graft-in-valved-conduit setting was <10 mmHg in all 4 conduits. CONCLUSIONS The study showed excellent in vitro performance of trileaflet polytetrafluoroethylene valved conduits. Its valved stent graft transformation provided data which may serve as a reference for transcatheter valve-in-valve research in the future.

Analysis of an Artificial Ventricle and Mock Circulatory System

1977 ◽  
Vol 99 (4) ◽  
pp. 184-188 ◽  
Author(s):  
K. M. High ◽  
J. A. Brighton ◽  
A. D. Brickman ◽  
W. S. Pierce
Keyword(s):  
Artificial Heart ◽  
Circulatory System ◽  
Experimental Tests ◽  
Mean Flow ◽  
Actual System ◽  
Mock Circulatory System ◽  
System A ◽  
The Mean ◽  
Artificial Ventricle ◽  
Good Agreement

A mathematical model is developed for calculating the pressures and flows in an artificial heart, its pneumatic drive unit, and a mock circulatory system. The system is divided into convenient subsystems to facilitate the analysis, and each subsystem is then analyzed separately. The set of independent equations developed is solved on a computer and corresponding experimental tests are made on the actual system. A comparison of the experimental and computer results shows good agreement for the mean flow rate through the pump and also for several instantaneous pressures and flow rates in the system.

In Vitro Study of Flow Regulation for Pulmonary Insufficiency Using Diode Valves

2007 ◽  
Author(s):  
Tiffany A. Camp ◽  
Stephanie Hequembourg ◽  
Richard S. Figliola ◽  
Tim McQuinn
Keyword(s):  
Pulmonary Valve ◽  
Pulmonary Regurgitation ◽  
Circulatory System ◽  
In Vitro Study ◽  
Pulmonary Insufficiency ◽  
Pressure Gradients ◽  
Right Heart ◽  
Mock Circulatory System ◽  
The Right

The operating pressures in the right heart are significantly lower than those of the left heart and with marked differences in the circulation impedances. The pulmonary circulation shows a tolerance for mild regurgitation and pressure gradient [1]. Pulmonary regurgitation fractions on the order of 20% and transvalvular pressure gradients of less than 25mm Hg are considered mild [4]. Given this tolerance, we examine the concept of using a motionless valve to regulate flow in the pulmonary position. In a previous study, the use of fluid diodes was shown to be a promising concept for use as a pulmonary valve [2]. In this study, we test two different diode designs. For each diode valve, flow performance was documented as a function of pulmonary vascular resistance (PVR) and compliance. Tests were done using a pulmonary mock circulatory system [3] over the normal adult range of PVR and compliance settings.

scholarly journals To Balloon or Not to Balloon? The Effects of an Intra-Aortic Balloon-Pump on Coronary Artery Flow during Extracorporeal Circulation Simulating Normal and Low Cardiac Output Syndromes

2021 ◽  
Vol 10 (22) ◽  
pp. 5333
Author(s):  
Philippe Reymond ◽  
Karim Bendjelid ◽  
Raphaël Giraud ◽  
Gérald Richard ◽  
Nicolas Murith ◽  
...  
Keyword(s):  
Heart Failure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Coronary Artery ◽  
Coronary Blood Flow ◽  
Low Cardiac Output ◽  
Coronary Artery Flow ◽  
Artery Flow

ECMO is the most frequently used mechanical support for patients suffering from low cardiac output syndrome. Combining IABP with ECMO is believed to increase coronary artery blood flow, decrease high afterload, and restore systemic pulsatile flow conditions. This study evaluates that combined effect on coronary artery flow during various load conditions using an in vitro circuit. In doing so, different clinical scenarios were simulated, such as normal cardiac output and moderate-to-severe heart failure. In the heart failure scenarios, we used peripheral ECMO support to compensate for the lowered cardiac output value and reach a default normal value. The increase in coronary blood flow using the combined IABP-ECMO setup was more noticeable in low heart rate conditions. At baseline, intermediate and severe LV failure levels, adding IABP increased coronary mean flow by 16%, 7.5%, and 3.4% (HR 60 bpm) and by 6%, 4.5%, and 2.5% (HR 100 bpm) respectively. Based on our in vitro study results, combining ECMO and IABP in a heart failure setup further improves coronary blood flow. This effect was more pronounced at a lower heart rate and decreased with heart failure, which might positively impact recovery from cardiac failure.

135 In vitro antithrombogenic testing for centrifugal blood pumps using a mock circulatory system

2008 ◽  
Vol 2007.20 (0) ◽  
pp. 275-276
Author(s):  
Osamu MARUYAMA ◽  
Daisuke SUGIYAMA ◽  
Yosuke TOMARI ◽  
Ryo KOSAKA ◽  
Masahiro NISHIDA ◽  
...  
Keyword(s):  
Circulatory System ◽  
Mock Circulatory System ◽  
Blood Pumps

Aortic Pressure Estimation With Electro-Mechanical Circulatory Assist Devices

1993 ◽  
Vol 115 (2) ◽  
pp. 187-194 ◽  
Author(s):  
J. F. Gardner ◽  
M. Ignatoski ◽  
U. Tasch ◽  
A. J. Snyder ◽  
D. B. Geselowitz
Keyword(s):  
Initial Conditions ◽  
Circulatory System ◽  
Time History ◽  
Aortic Pressure ◽  
Operating Conditions ◽  
Observer Performance ◽  
Mean Deviation ◽  
Mock Circulatory System ◽  
The Mean

An adaptive technique for the estimation of the time history of aortic pressure (from applied voltage and position feedback) has been designed, implemented, and bench tested using the Penn State Electric Ventricular Assist Device (EVAD). This method, known in the field of automatic control as a dynamic observer, utilizes gains which were determined using experimental data collected while the EVAD was running on a mock circulatory system. An adaptive scheme provides the observer with a method of changing its initial conditions on a stroke-by-stroke basis which improves observer performance. In both determining the feedback gains and developing the adaptation scheme, a range of beat rates and pressure loads was taken into account to yield satisfactory observer performance over a range of operating conditions. The observer was implemented, its performance was verified in vitro and results are reported. In the six experimental operating conditions, the beat rate ranged from 56-104 beats per minute (bpm) and the span of the mean systolic aortic pressure was 10.7-18.7 kPa (80–140 mmHg). For these cases, the mean deviation between the actual and estimated aortic pressure during the latter two-thirds of systole was 0.41 kPa (3.1 mmHg).

scholarly journals TMAO, a seafood-derived molecule, produces diuresis and reduces mortality in heart failure rats

2020 ◽  
Author(s):  
Marta Gawrys-Kopczynska ◽  
Marek Konop ◽  
Klaudia Maksymiuk ◽  
Katarzyna Kraszewska ◽  
Ladislav Derzsi ◽  
...  
Keyword(s):  
Heart Failure ◽  
Hydrostatic Stress ◽  
Oral Treatment ◽  
Circulatory System ◽  
Correlation Spectroscopy ◽  
Sprague Dawley ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Contracting Heart

ABSTRACTBackgroundThere is an ongoing debate whether trimethylamine-oxide (TMAO), a molecule present in seafood and a derivate of microbiota metabolism, is beneficial or harmful for the circulatory system. Interestingly, deep-water animals accumulate TMAO that protects proteins such as lactate dehydrogenase (LDH) against high hydrostatic pressure. We hypothesized that TMAO may benefit the circulatory system by protecting cardiac LDH exposed to hydrostatic stress (HS) produced by contracting heart.Methods and ResultsMale, 6-week-old, Sprague-Dawley (SD, n=40) and Spontaneously-Hypertensive-Heart-Failure (SHHF n=18) rats were divided into either Water or TMAO oral treatment. After 56 weeks, half of Water and TMAO SD rats were given isoprenaline (ISO) to produce catecholamine stress. In vitro, LDH with or without TMAO was exposed to HS (changes in pressure 0-250mmHg x 280min−1) and was evaluated using fluorescence correlation spectroscopy. After 58 weeks of the treatment survival was 100% in SD-Water, SD-TMAO, ISO-TMAO and 90% in ISO-Water. In SHHF-Water survival was 66% vs 100% in SHHF-TMAO. In general, TMAO-treated rats showed higher diuresis and natriuresis. In comparison to SHHF-Water, SHHF-TMAO showed significantly lower diastolic arterial blood pressure, plasma NT-proBNP and expression of angiotensinogen and AT1 receptors in the heart. In separate experiments, intravenous TMAO but not vehicle or urea significantly increased diuresis in SD. In vitro, exposure of LDH to HS with or without TMAO did not affect the protein structure.ConclusionsTMAO reduces mortality in SHHF rats that is associated with diuretic, natriuretic and hypotensive effects. HS produced by the contracting heart is neutral for cardiac LDH structure.

scholarly journals Heart Failure in Infancy and Childhood

2019 ◽  
Vol 16 (1-2) ◽  
pp. 1-10
Author(s):  
Dan G. McNamara
Keyword(s):  
Heart Failure ◽  
Cardiac Output ◽  
Surgical Repair ◽  
Left Heart ◽  
Oxygen Utilization ◽  
Left Heart Failure ◽  
Circulating Blood Volume ◽  
Infancy And Childhood ◽  
Cardiovascular Surgeon ◽  
Rapid Relief

Recognition of heart failure, especially left heart failure is often more difficult in the infant than the medical management. Treatment of failure is aimed at: Rapid relief of congestion in vital organs such as the lung and Improving the oxygen supply to deprived organs. Basically the plan should be aimed at increasing cardiac output, decreasing circulating blood volume and preventing conditions which call for increased oxygen utilization. For patients with pulmonary edema attention is directed at improving ventilation as much as in improving cardiac output. Heart failure in the infant may now be treated with greater optimism and hope than was justified ten years ago. Some infants recover entirely with no further treatment needed while others recover sufficiently to reach the cardiovascular surgeon in a reasonable state for definitive surgical repair.

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