Cardiac Monitoring Devices Research Articles

Paroxysmal Atrial Fibrillation in Cryptogenic Stroke: an Overlooked Explanation?

Approximately one third of ischemic strokes are labeled cryptogenic because the etiology is unknown despite a thorough evaluation. Paroxysmal atrial fibrillation carries the same risk of ischemic stroke as persistent atrial fibrillation and has increasingly gained attention as a potential source of cryptogenic stroke. Recent trials utilizing long-term cardiac monitoring devices have demonstrated high rates of previously undetected paroxysmal atrial fibrillation in patients with cryptogenic stroke. Newly detected atrial fibrillation has subsequently changed treatment and increased the use of oral anticoagulation in these studies. Other trials have shown an increased risk of stroke and thromboembolism in patients with device-detected subclinical tachyarrhythmias. Together, these studies suggest an important relationship between episodes of paroxysmal atrial fibrillation and the risk of cryptogenic stroke, but further investigations are needed to guide diagnostic and therapeutic decisions.

A non-contact capacitance based electrocardiograph and associated heart-rate detection using enhanced Fourier interpolation method.

Cardio-vascular health monitoring has gained considerable attention in the recent years. Principle of non-contact capacitive electrocardiograph (ECG) and its applicability as a valuable, low-cost, easy-to-use scheme for cardio-vascular health monitoring has been demonstrated in some recent research papers. In this paper, we develop a complete non-contact ECG system using a suitable front-end electronic circuit and a heart-rate (HR) measurement unit using enhanced Fourier interpolation technique. The front-end electronic circuit is realized using low-cost, readily available components and the proposed HR measurement unit is designed to achieve fairly accurate results. The entire system has been extensively tested to verify its efficacy and test results show that the developed system can estimate HR with an accuracy of ±2 beats. Detailed tests have been conducted to validate the performance of the system for different cloth thicknesses of the subject. Some basic tests which illustrate the application of the proposed system for heart-rate variability estimation has been conducted and results reported. The developed system can be used as a portable, reliable, long-term cardiac health monitoring device and can be extended to human drowsiness detection.

Cardiological aspects of stroke prevention.

Many cardiac disorders and their treatment are associated with an increased risk for ischemic or hemorrhagic stroke, so it is important for cardiologists to be aware of recent advances in the field of stroke prevention. Atrial fibrillation (AF) is the most common cardiac disorder associated with a substantial risk for ischemic stroke (IS). The availability of implantable cardiac monitoring devices has substantially increased the detection rate of occult AF after IS. The 4 new oral anticoagulants have advantages when compared with warfarin, the standard therapy in AF to prevent IS, demonstrating a reduced risk for IS or intracerebral hemorrhage. Patients with cardiomyopathy, cardiac valve replacement, recent myocardial infarction, larger aortic arch atheroma and patent foramen ovale all have some level of increased risk for IS. The best approach for IS prevention in these disorders remains unsettled and varying approaches are recommended.

Are There the Antiarrhythmic Effects of Omega3 Polyunsaturated Fatty Acids in Cardiosurgical Patients?

Objective: to test the hypothesis that the perioperative use of omega3 polyunsaturated fatty acids (ω3PUFA) as intravenous infusion will reduce the risk of postoperative atrial fibrillation (POAF) in patients with coronary heart disease operated on under extracorporeal circulation. Subjects and methods. A doubleblind prospective controlled study was conducted in 39 patients who were randomized into two groups: 1) 18 patients were infused with ω3PUFA (Omegaven, Fresenius Kabi, Germany), beginning before inducing anesthesia in a dose of 200 mg/kg/day within the first 24 hours and 100 mg/kg/day on days 2 to 7 postsurgery; 2) 21 received placebo (Intralipid, Fresenius Kabi, Germany) in the equivalent dose. The primary end point was freedom from POAF during 2 months after surgery. POAF was examined using a subcutaneously implanted continuous cardiac rhythm monitoring device (Reveal XT, Medtronic, USA). Monitoring readings were taken on day 10 at 3, 6, 12, and 24 months following surgery. Results. POAF was observed in 4 (19%) patients in the placebo group and in 5 (27.8%) in the ω3PUFA group on days 10 postsurgery (p=0.88). During 2year followup, POAF was revealed in 5 (27.8%) patients in the control group and in 6 (35.3%) in the ω3PUFA group (p=0.9). The duration of POAF was associated with the risk of rehospitalizations for decompensated heart failure (regression coefficient, 0.24; standard error, 0.02; p<0.0001; R2=0.74). Conclusion. The results of the study do not support the efficiency of perioperatively using ω3PUFA to prevent POAF

Novel wireless devices for cardiac monitoring.

The digital revolution and the rapid development of smartphones, mobile connectivity, and social networking have changed the way we live. The average American is constantly connected via high bandwidth to a vast network of data and sophisticated digital platforms, with >90% of American adults owning a cell phone and 55% having a smartphone.1 The digital revolution has transformed virtually every industry and every facet of our personal lives but has been conspicuously absent from the world of medicine. Physicians and healthcare networks have been slow to adopt electronic medical records and to integrate medical data with the ubiquitous mobile device. Recently, however, novel devices for wireless monitoring have emerged and begun to be integrated with the care of the cardiac patient. We believe that the evolution of these wireless cardiac monitoring devices will mark a new era in medicine and a transition from population-level health care to individualized medicine in which suitable patients are equipped with advanced biosensors that, in turn, have their data processed through sophisticated algorithms to predict events before they occur. This review is meant to be a comprehensive overview of the novel wireless cardiac monitoring devices that are available, as well as the technologies that are currently under development and poised to revolutionize the way we practice cardiology. A comprehensive list of a number of devices that are currently available or under development is given in the Table for reference. View this table: Table. Comprehensive Overview of Existing Wireless Cardiac Monitoring Devices Cardiac arrhythmias such as atrial fibrillation are common and can be associated with adverse outcomes such as embolic stroke. Less common but more malignant rhythm disorders such as ventricular tachycardia can herald sudden cardiac death.2 The identification and management of arrhythmias in the patient with palpitations, syncope, a history of arrhythmia, or high risk for sudden …

A novel heart sound activity detection framework for automated heart sound analysis

In automated heart sound analysis and diagnosis, a set of clinically valued parameters including sound intensity, frequency content, timing, duration, shape, systolic and diastolic intervals, the ratio of the first heart sound amplitude to second heart sound amplitude (S1/S2), and the ratio of diastolic to systolic duration (D/S) is measured from the PCG signal. The quality of the clinical feature parameters highly rely on accurate determination of boundaries of the acoustic events (heart sounds S1, S2, S3, S4 and murmurs) and the systolic/diastolic pause period in the PCG signal. Therefore, in this paper, we propose a new automated robust heart sound activity detection (HSAD) method based on the total variation filtering, Shannon entropy envelope computation, instantaneous phase based boundary determination, and boundary location adjustment. The proposed HSAD method is validated using different clean and noisy pathological and non-pathological PCG signals. Experiments on a large PCG database show that the HSAD method achieves an average sensitivity (Se) of 99.43% and positive predictivity (+P) of 93.56%. The HSAD method accurately determines boundaries of major acoustic events of the PCG signal with signal-to-noise ratio of 5dB. Unlike other existing methods, the proposed HSAD method does not use any search-back algorithms. The proposed HSAD method is a quite straightforward and thus it is suitable for real-time wireless cardiac health monitoring and electronic stethoscope devices.

5 Surface Electrocardiogram Signals Variation with Posture in Normal Adults and in Adults with Congenital Heart Disease and its Clinical Implication

IntroductionAmbulatory cardiac monitoring devices and the novel subcutaneous ICD (SICD) sensing algorithms are based on the surface electrocardiograms (ECGs) parameters for detection and discrimination of arrhythmias. However the impact of...

The effects of family-friend visits on anxiety, physiological indices and well-being of MI patients admitted to a coronary care unit

ObjectiveTo investigate the effect of family-friend visits on anxiety, physiological indices and well-being of patients with acute myocardial infarction. MethodsA checklist was used to gather socio-demographic data and physiologic indices including blood pressure, heart rate, respiratory rate, and arterial oxygen saturation. The short-form of the Spielberger state anxiety inventory, a visual analog scale well-being and cardiac monitoring devices were used for collecting data. ResultsPatients exhibited a lower heart rate and respiratory rate in the normal range during the 10-min visiting period and within10 and 30 min after the visiting period. The arterial oxygen saturation increased in this period. After the visiting period, patients exhibited an increase in the sense of well-being and a decrease in the level of anxiety. ConclusionFamily-friend visits can improve MI patients' sense of well-being and decrease their anxiety. Moreover, the visits can help to keep the physiological indices within normal limits.

Simulation of Intraoperative Pacemaker Failure

Simulation of Intraoperative Pacemaker Failure

Ambulatory Cardiac Monitoring for Discharged Emergency Department Patients with Possible Cardiac Arrhythmias

IntroductionMany emergency department (ED) patients have symptoms that may be attributed to arrhythmias, necessitating outpatient ambulatory cardiac monitoring. Consensus is lacking on the optimal duration of monitoring. We describe the use of a novel device applied at ED discharge that provides continuous prolonged cardiac monitoring.MethodsWe enrolled discharged adult ED patients with symptoms of possible cardiac arrhythmia. A novel, single use continuous recording patch (Zio®Patch) was applied at ED discharge. Patients wore the device for up to 14 days or until they had symptoms to trigger an event. They then returned the device by mail for interpretation. Significant arrhythmias are defined as: ventricular tachycardia (VT) ≥4 beats, supraventricular tachycardia (SVT) ≥4 beats, atrial fibrillation, ≥3 second pause, 2nd degree Mobitz II, 3rd degree AV Block, or symptomatic bradycardia.ResultsThere were 174 patients were enrolled and all mailed back their devices. The average age was 52.2 (± 21.0) years, and 55% were female. The most common indications for device placement were palpitations 44.8%, syncope 24.1% and dizziness 6.3%. Eighty-three patients (47.7%) had ≥1 arrhythmias and 17 (9.8%) were symptomatic at the time of their arrhythmia. Median time to first arrhythmia was 1.0 days (IQR 0.2–2.8) and median time to first symptomatic arrhythmia was 1.5 days (IQR 0.4–6.7). 93 (53.4%) of symptomatic patients did not have any arrhythmia during their triggered events. The overall diagnostic yield was 63.2%ConclusionThe Zio®Patch cardiac monitoring device can efficiently characterize symptomatic patients without significant arrhythmia and has a higher diagnostic yield for arrhythmias than traditional 24–48 hour Holter monitoring. It allows for longer term monitoring up to 14 days.

Abstract 18775: Longterm Follow-Up After Surgical Ablation Therapy for Atrial Fibrillation Using an Implantable Cardiac Rhythm Monitoring Device

Objectives: After ablation, intermittent and symptom-based monitoring of the heart rhythm may not be reliable in identifying patients with ongoing atrial fibrillation (AF). For accuracy of rhythm surveillance after surgical ablation leadless implantable cardiac rhythm monitoring devices (ICM) were implanted. Methods: Surgically ablation of AF was accomplished following the Cox-Maze technique modified after Damiano. Lines were produced with bipolar radiofrequency using the AtriCure ® clamp. Continuity near the AV-valves was achieved applying the unipolar Isolator ® Pen. In each case concomitant cardiovascular procedures were necessary. At the end of the interventions the ICMs were implanted. Amiodaron was given for six and phenprocoumon for twelve postoperative months. Patient follow-up was conducted by means of transtelephonic transmission on a monthly basis. The attending physician in private practice got access to the remote monitoring. Results: A group of 27 patients were continuously monitored over a period of three years. Preoperatively, 15% of the patients had paroxysmal, 59% persistent and 26% permanent AF. Mean postoperative AF burden as indicated by ICM declined continuously over twelve months: From 35 to 7% (preoperative paroxysmal), 60 to 25% (preoperative persistent) and 83 to 64% (preoperative permanent). ). The treatment is less effective for patients with permanent AF and severe heart failure. Atrial flutter was detected in two patients. Symptomatic bradycardia necessitated two permanent pacemakers. Conclusion: Continuous heart rhythm monitoring with an ICM detected AF burden higher then expected. The duration of AF decreases significantly in the course of the first year only. After this period of time, anticoagulation could be reconsidered. Intensified heart rhythm follow-up and local medical networking can improve cardiac therapy.

Performance of an external transtelephonic loop recorder for automated detection of paroxysmal atrial fibrillation.

Although atrial fibrillation (AF) is the most commonly encountered arrhythmia, some of the properties make its detection challenging. In daily practice, underdiagnosis can lead to less effective treatment in prevention of stroke. Based on data from studies on treatment of AF, more intensive follow-up strategies, including 7-day Holter recording, 30-day event recording, and even implantable cardiac monitoring devices, are suggested. The study purpose is to evaluate the performance of a continuous single-channel loop recorder with automatic AF detection and transtelephonic electrocardiogram (ECG) transmission capabilities. A consecutive cohort of 153 patients admitted to the stroke unit with a presumptive diagnosis of ischemic cerebrovascular accident was screened for AF. Twenty-four-hour rhythm observation was performed using a single-channel external loop recorder (ELR) configured for automated AF detection. A total of 45 patients with a known history of AF, AF on the admission ECG, or incomplete registrations were excluded. Extensive additional frequency-based settings were used to establish a reference registration. In total, 2923 recordings were transmitted. We evaluated all events, of which 1190 were designated by the device as AF. The sensitivity, specificity, PPV, and NPV for identifying AF using the ELR were, respectively, 93%, 51%, 5%, and 99%. In this ELR validation study, the dedicated AF detection algorithm showed to be highly sensitive but not specific for AF. Applicability of an ELR might be limited for efficacious detection of AF, as manual verification is mandatory for a vast amount of recordings.

Is there a role for new oral anticoagulants as primary and secondary stroke prevention in atrial fibrillation and intracranial stenosis?

Ischemic strokes in patients with atrial fibrillation (AF) are due to a variety of mechanisms, and are not necessarily the result of cardiogenic embolism. Due to improvement in imaging technology the detection of extraand intracranial stenoses is noninvasively possible, and improvements of cardiac monitoring devices have increased the detection rate of previously unknown AF in stroke patients [1]. The coincidence of AF and cerebral atherosclerosis leads to therapeutic considerations as illustrated by the following example.

Follow-up after surgical ablation therapy for atrial fibrillation (AF) using an implantable cardiac rhythm monitoring device (ICM)

Follow-up after surgical ablation therapy for atrial fibrillation (AF) using an implantable cardiac rhythm monitoring device (ICM)

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Noncontact electrosurgical grounding – A useful and safe tool in the initial surgical management of thermal injuries

BackgroundElectrosurgical instruments – one of the useful and most-used instruments within the surgeon's armamentarium – are potentially dangerous by causing unanticipated direct burns; fire occurring as a result of electrosurgical instruments and electromagnetic interference with a pacemaker, defibrillator, or cardiac monitoring device. MethodsThe Mega 2000 Patient Return Electrode System produced by Megadyne Medical Products is a noncontact electrode designed to provide adequate electrical return to facilitate function of electrocautery devices. We used this noncontact device in 67 patients (28 women, 39 men) with large burns during their stay in our burn unit and in 11 of these patients (4 women, 7 men) for escharotomies during admission in our burn care. ResultsThe device functioned well in all cases, no additional cutaneous burns on the patients’ body were noticed. ConclusionThis paper is a review of our experience with this noncontact electrosurgical grounding in burn surgery highlighting its advantages comparing with the conventional electrosurgical instruments.

Recent Patents on Ultrasound Thickness Measurements in Medicine

Ultrasound, today, with non-invasive and non-destructive features, has taken place between most popular and widely used diagnostic tools. Being inexpensive and portable has made ultrasound a tool that is preferred widely in medical diagnostic applications. Ultrasound thickness measurement devices are based on A-mode scanning and echo-ranging principle. This study examines the patents related to ultrasonic thickness measurement systems which are widely used in diagnostic medicine. In this paper, it has been revealed that, these systems are used in various fields of medicine to carry out thickness measurement, even of very thin and delicate tissues, such as blood vessels, without requiring surgical intervention. Keywords: A-mode scanning, echo-ranging, non-invasive, thickness measurement, Ultrasound Thickness Measurements, diagnostic ultrasound, diagnostic medicine, ultrasound devices, Cardiac monitoring device, Noninvasive diagnostic system, acoustic pulse-echo ranging system, echography, ultrasound therapy, High frequency ultrasound sys, pacemaker system, pacemaker

Electromagnetic Interference of Cardiac Rhythmic Monitoring Devices to Radio Frequency Identification: Analytical Analysis and Mitigation Methodology

Increasing density of wireless communication and development of radio frequency identification (RFID) technology in particular have increased the susceptibility of patients equipped with cardiac rhythmic monitoring devices (CRMD) to environmental electro magnetic interference (EMI). Several organizations reported observing CRMD EMI from different sources. This paper focuses on mathematically analyzing the energy as perceived by the implanted device, i.e., voltage. Radio frequency (RF) energy transmitted by RFID interrogators is considered as an example. A simplified front-end equivalent circuit of a CRMD sensing circuitry is proposed for the analysis following extensive black-box testing of several commercial pacemakers and implantable defibrillators. After careful understanding of the mechanics of the CRMD signal processing in identifying the QRS complex of the heart-beat, a mitigation technique is proposed. The mitigation methodology introduced in this paper is logical in approach, simple to implement and is therefore applicable to all wireless communication protocols.

Prolonged Rhythm Monitoring for the Detection of Occult Paroxysmal Atrial Fibrillation in Ischemic Stroke of Unknown Cause

Atrial fibrillation (AF), commonly encountered in patients with ischemic stroke and transient ischemic attack (TIA), confers a 5-fold increased risk of ischemic stroke.1,2 AF-related strokes are associated with an ≈50% increased risk of disability and 60% increased risk of death at 3 months compared with strokes of other etiologies.3 Paroxysmal AF (PAF), a self-terminating recurrent form of cardiac arrhythmia that comprises between 25% and 62% of AF cases, may present as a brief single episode of arrhythmia or as clusters of abnormal rhythm of variable duration, sometimes evolving into a more persistent or permanent form.4 The self-terminating nature of PAF may lead to its underdiagnosis and consequent use of less effective treatment strategies (aspirin instead of oral anticoagulation) in poststroke patients. To address the underdiagnosis of PAF in patients with ischemic stroke and TIAs, several treatment guidelines have singled out the identification of PAF as an important goal after a stroke/TIA.5–8 The diagnosis of PAF, however, poses a challenge. Several features of AF (such as its brief duration, episodic frequency, and asymptomatic presentations) make its detection difficult and elusive to bedside screening measures, such as pulse monitoring and routine ECGs. To date, several studies have explored the use of prolonged noninvasive and invasive cardiac monitoring devices to identify AF but with variable success. After detection of AF, a cardioembolic mechanism is often inferred and anticoagulation occasionally prescribed for secondary stroke prevention. The routine use of cardiac monitoring to identify patients with PAF who will benefit from anticoagulation has been reported to be cost-effective.9 In this review, we provide an overview of the different methods of cardiac monitoring, summarize studies that investigated the incidence of PAF after stroke, and highlight gaps in our understanding of the pathogenic and prognostic significance of AF …

Prediction of Stroke Risk in Atrial Fibrillation, Prevention of Stroke in Atrial Fibrillation, and the Impact of Long-Term Monitoring for Detecting Atrial Fibrillation

Atrial fibrillation (AF) is a large public health problem that affects about 1% of the population in the United States. It confers an increased risk for stroke and thromboembolism, but the stroke risk is not equal in all patients. Further refinement in stratifying stroke risk in patients with AF will help in properly directing therapy for AF patients while minimizing adverse events. Warfarin is the first-line treatment for stroke reduction in patients with AF, but many new drugs are on the horizon that will significantly change practice. New and improved cardiac monitoring techniques and devices will help with detection of AF in those at risk for stroke and will assist in assessing which patients will most benefit from anticoagulation.