Heart Rate Variability: A possible machine learning biomarker for mechanical circulatory device complications and heart recovery

Cardiovascular disease continues to be the number one cause of death in the United States, with heart failure patients expected to increase to \u3e8 million by 2030. Mechanical circulatory support (MCS) devices are now better able to manage acute and chronic heart failure refractory to medical therapy, both as bridge to transplant or as bridge to destination. Despite significant advances in MCS device design and surgical implantation technique, it remains difficult to predict response to device therapy. Heart rate variability (HRV), measuring the variation in time interval between adjacent heartbeats, is an objective device diagnostic regularly recorded by various MCS devices that has been shown to have significant prognostic value for both sudden cardiac death as well as all-cause mortality in congestive heart failure (CHF) patients. Limited studies have examined HRV indices as promising risk factors and predictors of complication and recovery from left ventricular assist device therapy in end-stage CHF patients. If paired with new advances in machine learning utilization in medicine, HRV represents a potential dynamic biomarker for monitoring and predicting patient status as more patients enter the mechanotrope era of MCS devices for destination therapy

ECG Arrhythmias and Technical Alarms during Left Ventricular Assist Device (LVAD) Therapy and its Potential Impact on Alarm Fatigue

AbstractBackground: During alarm fatigue, true alarms can go unnoticed placing patients at risk for untoward outcomes. Patients with a left ventricular assist device (LVAD) may create challenges during electrocardiographic (ECG) monitoring due to technical alarms (i.e., artifact, ECG leads off), noise and vibrations associated with LVADs, and being able to tolerate some arrythmias. Clinical Nurse Specialists play a central role in and developing evidenced based strategies to improve alarm safety with the ultimate goal of improving patient outcomes. Purpose/Aim: In this case series, we analyze three patients being treated with an LVAD device in the cardiac intensive care unit (ICU) and determine: 1) the number and type of audible arrhythmia alarms; 2) the number of true versus false arrhythmias; 3) the number, type and duration of technical alarms; and 4) report alarm burden. Methods: Secondary analysis using data from the University of California, San Francisco (UCSF) Alarm Study. Results: There were a total of 547 arrhythmia alarms and 98% were false. There were 25,232 technical alarms. Of 514 total hours of ECG monitoring, technical alarms occurred for 65.9 (13%) hours. Alarm burden of 50.15 alarms per monitored hour in the ICU. Conclusion: Audible arrhythmia alarms are common in LVAD patients, and the vast majority are false. Importantly, none of the arrhythmia alarms led to an untoward event (i.e., code blue or death). Technical alarms are also very common and occur for hours during routine ECG monitoring. Continuous ECG monitoring creates unique challenges in LVAD patients. Future studies are needed to explore strategies, both clinical and algorithm bases, to improve the accuracy of arrhythmia detection and minimize technical alarms in LVAD patients

LVAD Occlusion Condition Monitoring Using Boost Classification Trees

Cardiac related diseases are a serious health risk for adults. Consequently, therapies exist to treat these aliments such as heart transplant and medication. Heart transplant remains the gold standard for treating severe heart failure, however left ventricular assistive devices, a cardiac blood pump, are become a viable long term treatment. Unfortunately, with the benefits of these devices come risks of clot formation. These occlusions can cause strokes, further cardiac damage, or even death. Therefore, it is critical that these occlusions be detected as early as possible. This work presents an expanded method to non-invasively monitor the condition of a Thoratec HeartMate II ventricular assist device through the application of a boosted classification tree. In addition, both inflow and outflow blockages measured at aorta and pump locations were experimentally tested on a cardiac phantom. The proposed method presents a potential outpatient diagnostic method that may assist experienced cardiologists in their treatment of LVAD patients

Outcomes of patients after successful left ventricular assist device explantation: a EUROMACS study

Aims: Sufficient myocardial recovery with the subsequent explantation of a left ventricular assist device (LVAD) occurs in approximately 1–2% of the cases. However, follow-up data about this condition are scarcely available in the literature. This study aimed to report the long-term outcomes and clinical management following LVAD explantation. Methods and results: An analysis of the European Registry for Patients with Mechanical Circulatory Support was performed to identify all adult patients with myocardial recovery and successful explantation. Pre-implant characteristics were retrieved and compared with the non-recovery patients. The follow-up data after explantation were collected via a questionnaire. A Kaplan–Meier analysis for freedom of the composite endpoint of death, heart transplantation, LVAD reimplantion, or heart failure (HF) relapse was conducted. A total of 45 (1.4%) cases with myocardial recovery resulting in successful LVAD explantation were identified. Compared with those who did not experience myocardial recovery, the explanted patients were younger (44 vs. 56 years, P < 0.001), had a shorter duration of cardiac disease (P < 0.001), and were less likely to have ischaemic cardiomyopathy (9% vs. 41.8%, P < 0.001). Follow-up after explantation could be acquired in 28 (62%) cases. The median age at LVAD implantation was 43 years (inter-quartile range: 29–52),

Individualized Biventricular Epicardial Augmentation Technology in a Drug-Induced Porcine Failing Heart Model

For treatment of advanced heart failure, current strategies include cardiac transplantation or blood-contacting pump technology associated with complications, including stroke and bleeding. This study investigated an individualized biventricular epicardial augmentation technology in a drug-induced porcine failing heart model. A total of 11 pigs were used, for the assessment of hemodynamics and cardiac function under various conditions of support pressures and support durations (n = 4), to assess device positioning and function by in vivo computer tomographic imaging (n = 3) and to investigate a minimally invasive implantation on the beating heart (n = 4). Support pressures of 20-80 mmHg gradually augmented cardiac function parameters in this animal model as indicated by increased left ventricular stroke volume, end-systolic pressures, and decreased end-diastolic pressures. Strong evidence was found regarding the necessity of mechanical synchronization of support end with the isovolumetric relaxation phase of the heart. In addition, the customized, self-expandable implant enabled a marker-guided minimally invasive implantation through a 4cm skin incision using fluoroscopy. Correct positioning was confirmed in computer tomographic images. Continued long-term survival investigations will deliver preclinical evidence for further development of this concept

RPM and flow modulation for a continuous flow left ventricular assist device to increase vascular pulsatility : a computer simulation, mock circulation, and in-vivo animal study.

Purpose: Continuous flow (CF) left ventricular assist devices (LVAD) support diminishes vascular pressure pulsatility. Despite its recent clinical success and reliability, CF LVAD support has been associated with adverse events including gastrointestinal bleeding, aortic valve insufficiency, and hemorrhagic strokes. To overcome these limitations, we have developed flow/RPM modulation algorithms to provide vascular pulsatility using a CF LVAD. Methods: The effects of timing and synchronizing the CF LVAD flow/RPM modulation to the native ventricle, modulation amplitude, and modulation widths were studied on the native ventricle and vasculature using computer simulation, mock loop, and animal model studies. A total of over 100 combinations of flow modulation algorithms to modulate CF LVAD flow/RPM were tested for partial and full LVAD support modes. Results: Modulation of CF LVAD flow/RPM resulted in an increased arterial pressure pulsatility of up to 50 mmHg during asynchronous modulation and 20 mmHg during synchronous modulation. Synchronous CF LVAD RPM modulation allowed for a range of reduced left ventricular external work (LVEW) as compared to un-modulated CF LVAD support conditions. Full support co-pulsation (high RPM during systole, low RPM during diastole) created greater pulse pressures as compared to counter pulsation (high RPM during diastole, low RPM during systole). However, all full support modulation timings yielded higher pulse pressure than normal full support CF LVAD flow at low ventricular contractilities. Importantly, reduction in LVEW and increase in pulsatility may be adjusted to user-defined values while maintaining the same average CF LVAD flow rate. Conclusions: These LVAD flow/RPM modulations may reduce the incidence of adverse events associated with the CF LVAD therapy by increasing vascular pulsatility and reducing vascular impedance. Further, these methods of CF LVAD flow/RPM modulation may enable tailored unloading of the native ventricle to provide rest and rehabilitation (maximal unloading to rest followed by gradual reloading to wean), which may promote sustainable myocardial recovery

Modeling andsimulationofspeedselectiononleftventricular assist devices

The control problem for LVADs is to set pump speed such that cardiac output and pressure perfusion are within acceptable physiological ranges. However, current technology of LVADs cannot provide for a closed-loop control scheme that can make adjustments based on the patient\u27s level of activity. In this context, the SensorART Speed Selection Module (SSM) integrates various hardware and software components in order to improve the quality of the patients\u27 treatment and the workflow of the specialists. It enables specialists to better understand the patient-device interactions, and improve their knowledge. The SensorART SSM includes two tools of the Specialist Decision Support System (SDSS); namely the Suction Detection Tool and the Speed Selection Tool. A VAD Heart Simulation Platform (VHSP) is also part of the system. The VHSP enables specialists to simulate the behavior of a patient?s circulatory system, using different LVAD types and functional parameters. The SDSS is a web-based application that offers specialists with a plethora of tools for monitoring, designing the best therapy plan, analyzing data, extracting new knowledge and making informative decisions. In this paper, two of these tools, the Suction Detection Tool and Speed Selection Tool are presented. The former allows the analysis of the simulations sessions from the VHSP and the identification of issues related to suction phenomenon with high accuracy 93%. The latter provides the specialists with a powerful support in their attempt to effectively plan the treatment strategy. It allows them to draw conclusions about the most appropriate pump speed settings. Preliminary assessments connecting the Suction Detection Tool to the VHSP are presented in this paper

Current management of patients with severe acute peripartum cardiomyopathy: practical guidance from the Heart Failure Association of the European Society of Cardiology Study Group on peripartum cardiomyopathy

No abstract available

A multidisciplinary approach for the emergency care of patients with left ventricular assist devices: A practical guide

The use of a left ventricular assist device (LVAD) as a bridge-to-transplantation or destination therapy to support cardiac function in patients with end-stage heart failure (HF) is increasing in all developed countries. However, the expertise needed to implant and manage patients referred for LVAD treatment is limited to a few reference centers, which are often located far from the patient's home. Although patients undergoing LVAD implantation should be permanently referred to the LVAD center for the management and follow-up of the device also after implantation, they would refer to the local healthcare service for routine assistance and urgent health issues related to the device or generic devices. Therefore, every clinician, from a bigger to a smaller center, should be prepared to manage LVAD carriers and the possible risks associated with LVAD management. Particularly, emergency treatment of patients with LVAD differs slightly from conventional emergency protocols and requires specific knowledge and a multidisciplinary approach to avoid ineffective treatment or dangerous consequences. This review aims to provide a standard protocol for managing emergency and urgency in patients with LVAD, elucidating the role of each healthcare professional and emphasizing the importance of collaboration between the emergency department, in-hospital ward, and LVAD reference center, as well as algorithms designed to ensure timely, adequate, and effective treatment to patients with LVAD. Copyright © 2022 Cameli, Pastore, Mandoli, Landra, Lisi, Cavigli, D'Ascenzi, Focardi, Carrucola, Dokollari, Bisleri, Tsioulpas, Bernazzali, Maccherini and Valente