Cardiac Monitoring Devices Research Articles

PHYSIOLOGIC INDICES OF PATIENTS BEFORE, DURING AND AFTER VISIT IN CORONARY CARE UNIT AT IMAM KHOMEINI HOSPITAL IN ARDEBIL

Physiologic indices of patients before, during and after visit in coronary care unit at Imam Khomeini hospital in Ardebil Kamrani, F. 1 * (MSN); Seyedjavadi, M. 2 (MSN); Abedsaeedi, Zh. 3 (PhD); Ezzati, Zh. 4 (MSN); Alavimajd, H. 5 (PhD); Hosseinian, A. 6 (MD) 1. Lecturer, Dept. of Medical-Surgical Nursing, Faculty of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2. Alumnus, Faculty of Nursing and Midwifery, Shahid Beheshti University of Medical Science, Tehran, Iran 3. Assistant Professor, Dept. of Medical-Surgical Nursing, Faculty of Nursing and Midwifery, Shahid Beheshti University of Medical Science, Tehran, Iran. 4. Lecture, Dept. of Medical-Surgical Nursing, Faculty of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 5. Associate Professor, Dept. of Biostatistics, Faculty of Paramedical, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 6. Cardiologist, Faculty of Medicine, Ardebil University of Medical Sciences, Ardebil, Iran. Abstract Background and aim Visit is an essential issue in hospitals and of patients' basic needs in coronary care units (CCUs). However, there is no evidence regarding its physiologic effects on them. The aim of this was to determine the physiologic indexes of patients before, during and after visit at CCU of Imam Khomeini Hospital in Ardebil. Materials and methods In this descriptive study, 50 patients with acute myocardial infarction were selected through convenience sampling method. A questionnaire and a cardiac monitoring device were used for data collection. Content method and calibration the device were used for validity and reliability of the tools respectively. ANOVA with repeated measurements was used for data analysis. Findings %72 of patients was male and %28 was female. Their mean age was 59.8. Significant differences were found between s ystolic, diastolic and mean arterial pressures; heart as well as respiratory rates; temperature; and oxygen saturation before, during and after the visits. Accordingly, the indexes increased significantly by the start of visits and turned back to the previous state after them with no significant difference in before-after amounts. Conclusion It seems that the physiologic indices of patients change in normal range during visits and return to their primary state after 30 minutes from the end of visits with no clinical importance. Keywords: Visit, Coronary Care Unit (CCU), Physiologic indexes. * Corresponding Author: Lecturer, Dept. of Medical-Surgical Nursing, Faculty of Nursing and Midwifery, Shahid Beheshti University of Medical Sciences, Tehran, Iran. E-mail: comruni1338@yahoo.com

Twenty-Four–Hour Holter Monitor Follow-Up Does Not Provide Accurate Heart Rhythm Status After Surgical Atrial Fibrillation Ablation Therapy

Twenty-four-hour Holter monitoring (24HM) is commonly used to assess cardiac rhythm after surgical therapy of atrial fibrillation (AF). However, this "snapshot" documentation leaves a considerable diagnostic window and only stores short-time cardiac rhythm episodes. To improve accuracy of rhythm surveillance after surgical ablation therapy and to compare continuous heart rhythm surveillance versus 24HM follow-up intraindividually, we evaluated a novel implantable continuous cardiac rhythm monitoring (IMD) device (Reveal XT 9525). Forty-five cardiac surgical patients (male 37, mean age 69.7+/-9.2 years) with a mean preoperative AF duration of 38+/-45 m were treated with either left atrial epicardial high-intensity focus ultrasound ablation (n=33) or endocardial cryothermy (n=12) in case of concomitant mitral valve surgery. Rhythm control readings were derived simultaneously from 24HM and IMD at 3-month intervals with a total recording of 2021 hours for 24HM and 220 766 hours for IMD. Mean follow-up was 8.30+/-3.97 m (range 0 to 12 m). Mean postoperative AF burden (time period spent in AF) as indicated by IMD was 37+/-43%. Sinus rhythm was documented in 53 readings of 24HM, but in only 34 of these instances by the IMD in the time period before 24HM readings (64%, P<0.0001), reflecting a 24HM sensitivity of 0.60 and a negative predictive value of 0.64 for detecting AF recurrence. For "real-life" cardiac rhythm documentation, continuous heart rhythm surveillance instead of any conventional 24HM follow-up strategy is necessary. This is particularly important for further judgment of ablation techniques, devices as well as anticoagulation and antiarrhythmic therapy.

Novel Implantable Device to Detect Cardiac Allograft Rejection

Allograft rejection remains the nemesis of solid organ transplantation. Soul Mate is a novel implantable wireless data transmission system that analyzes 9 intramyocardial electrogram parameters recorded from 4 or 6 configurations of 2 or 3 epicardial leads to detect allograft rejection. This study determined the ability of the Soul Mate to detect early rejection of transplanted hearts. Five dogs underwent heterotopic cervical heart transplantation and simultaneous implantation of the Soul Mate's Cardiac Rejection Monitoring Device. Dogs were initially immunosuppressed, but subsequent drug discontinuation allowed allograft rejection to appear. Allograft biopsies were performed at regular intervals to determine rejection grade, which was compared to a calculated rejection score determined as percent change from baseline of values for each intramyocardial electrogram. There was significant correlation between the biopsy results and the evolution of 5 parameters. The strongest correlation (r=0.939; P<0.001) was obtained using the "general median" parameter from 4 configurations, assessed 1 day before the biopsy, with a sensitivity of 85.7% and a specificity of 100% compared to the myocardial biopsy results. The Soul Mate allograft rejection monitoring system accurately detected transplanted heart rejection in a canine model noninvasively with continuous sampling. This proof-of-concept study suggests that the Soul Mate could be used to more intensely and more frequently monitor cardiac allografts for rejection.

Not feeling well [medical equipment spectrum allocation

The article discusses how Europe could learn from the US when it comes to wireless medical equipment. The distributed management of the frequency spectrum in Europe is negatively affecting the region, making decision-making processes lengthy and difficult. In the medical equipment arena, where the unlicensed ISM bands are not exclusive, this is beginning seriously to impede progress. In contrast, the US decided to allocate dedicated frequencies for healthcare applications, a process that led to the introduction of what is now known as the wireless medical telemetry service (WMTS). The FCC set aside the 608-614 MHz,1395-1400 MHz and 1429-1432 MHz frequency bands for WMTS. Usage is limited to authorised healthcare providers and is regulated, to facilitate sharing of the spectrum and to help prevent interference among users. WMTS does not extend to prescribing data modulation schemes, communication protocols, etc. This has proved beneficial for the medical equipment industry, as it is allowing OEMs to optimise the data communications schemes for the particular application in hand (for example in cardiac monitoring devices). It also allows medical OEMs to make use of existing technology and components (e.g. DECT baseband processors) to speed the development of next-generation equipment.

Electrosurgery in otolaryngology-head and neck surgery: principles, advances, and complications.

Electrosurgical instruments are routinely used in many applications by otolaryngologist-head and neck surgeons; and a complete description of their historical development, physics of operation, histological effects, and technological advancements is necessary for our specialty to take full advantage of this instrumentation. Because of the electrical current, heat production, and common use associated with these instruments, compounded by the complex environments in which they are used, potential complications must be considered and are likely underreported in the literature. This thesis describes the important aspects of electrosurgery along with a study of complications so otolaryngologists can use these instruments to their fullest potential while limiting complications. National survey of electrosurgical complications. A survey addressing potential complications of electrosurgery was developed based on a review of the electrosurgical and complications literature. The electrosurgical complications were organized in the following categories: 1) unanticipated direct burns as a result of the active electrode contacting some tissue unintentionally; 2) unintentional burns as a result of capacitive coupling where radiofrequency (RF) current passes through a metallic instrument (such as forceps) and burns tissue in contact with that metallic instrument; 3) fires occurring as a result of electrosurgical instruments; 4) electromagnetic interference with a pacemaker, defibrillator, or cardiac monitoring device; and 5) other complications not included in the previous categories. The survey was mailed to the 620 members of the Society of University of Otolaryngologists. Of the 620 surveys mailed, 35 were returned by the post office for lack of a forwarding address and 296 were returned completed for a response rate of 49.7%. The respondents performed a total of 99,664 cases in the previous year. During that year, 324 complications related to electrosurgical instruments were reported. These included 219 unanticipated direct burns, 48 burns as a result current flow through a metallic retractor or instrument (capacitative coupling), 13 grounding pad burns, 11 fires, 32 cases of electromagnetic interference, and 1 hair loss at an incision site as a result of a cutting electrosurgical instrument. Information regarding the circumstances surrounding these complications and outcome are presented. Electrosurgery has proliferated since its original application by William T. Bovie and Harvey Cushing in the 1920s. Because surgeons use this technology frequently, a thorough understanding of these instruments and their potential complications is critical to their safe and successful use. Electrosurgical units operate on basic fundamental principles of physics and involve the passage of electrical current through tissue to create the desired tissue effect. With knowledge of the history, physics, techniques, histological effects, and safety issues of electrosurgery, the field will continue to proliferate and electrosurgery will continue to assist surgeons in alleviating human suffering.

Rationale and specifications for an automatic cardiac arrest-driven alarm and 911 caller ID (ACADA/911)

The rationale and specifications for a permanent non-invasive cardiac monitoring device are described, including both an alarm and a device-initiated call (giving patient residence identification) to the emergency services number 911, if cardiac arrest is detected. This device may be useful for high-risk cardiac patients, who incur an unwitnessed cardiac arrest, by providing a prompt call and alarm for early initiation of bystander CPR, cardiac defibrillation (if necessary), advanced cardiac life-support, and early transfer of resuscitated patients to a hospital cardiac care unit. Unwitnessed cardiac arrest patients otherwise have a dismal prognosis because of prolonged circulatory arrest times and late initiation of defibrillation attempts. With out-of-home unwitnessed cardiac arrest, ACADA-911 specifications also include a cardiac arrest-triggered determination of the patient's location through a commercially inexpensive global positioning system device, whose output is transmitted to EMS via an attached cellular phone/priority call network. A randomized controlled study evaluation of the device is proposed.

Automated ventricular tachyarrhythmia recognition: a combination of cycle length and nonlinear dynamics measurements.

Cardiac monitoring devices such as external cardioverter defibrillators and ICU computerized ECG monitoring systems sense individual QRS complexes to detect and subclassify ventricular tachyarrhythmias. Many algorithms that evaluate ECG morphology mark individual QRS complexes so that specific waveform characteristics can be measured. QRS sensors miss a percentage of electrogram events, especially during fibrillatory rhythms; thus, a morphology algorithm that helps subclassify arrhythmias without marking individual electrogram events may be more robust and improve arrhythmia detection accuracy. Four nonlinear dynamics calculations were evaluated for detecting ventricular tachyarrhythmias and for subclassifying monomorphic ventricular tachycardia (MVT) and polymorphic ventricular tachycardia (PVT). Five-second epochs of normal (NML, n = 48), MVT (n = 58), and PVT (n = 75) rhythms were presented to a statistical discriminant function based on cycle length (CL), and its performance was compared to two other discriminant functions, one consisting of the nonlinear dynamics calculations and one consisting of a combination of all variables. The discriminant function based on nonlinear dynamics calculations and CL detected 100% of the ventricular tachyarrhythmias, and subclassified more (P < 0.001) MVT and PVT arrhythmias (90%) than that based on CL alone (71%). The nonlinear dynamics measurements used in this study significantly increased the subclassification accuracy of the CL-based discriminant function, and they were calculated from ECG signals without marking individual QRS complexes. Therefore, arrhythmia detectors that use nonlinear dynamics measurements may commit fewer classification errors due to QRS undersensing and aid therapy decisions when circumstances suggest that QRS sensing is inaccurate.

Lack of agreement between measurement of ejection fraction by impedance cardiography versus radionuclide ventriculography

To determine the limits of agreement between left ventricular ejection fraction estimated using systolic time intervals from impedance cardiography and left ventricular ejection fraction estimated by radionuclide ventriculography. A prospective study for diagnostic tests using radionuclide ventriculography as the criterion standard. A large military teaching hospital. Twenty ambulatory adults scheduled for radionuclide ventriculography. A regression equation to estimate ejection fraction from systolic time intervals is available in a widely used impedance-based cardiac monitoring device. The estimated ejection fraction is then used in an equation with stroke volume estimated by the same device to calculate an end-diastolic volume. We studied the agreement of the ejection fraction as estimated by this device with the ejection fraction estimated by radionuclide ventriculography by obtaining simultaneous estimates of ejection fraction over a broad range of adult patients. Twenty ejection fraction pairs were analyzed. The correlation of ejection fraction by impedance cardiography to ejection fraction by radionuclide ventriculography was significant (r2 = .55; p < .002). However, the mean difference between the technologies was -8.85%, with a standard deviation of the differences of 7.15%, resulting in a 95% confidence range for agreement of -23.2% to +5.5%. The 95% confidence range defining the limits of agreement between ejection fraction by impedance cardiography and ejection fraction by radionuclide ventriculography is not clinically acceptable. In the opinion of the authors impedance cardiography should not be used in place of radionuclide ventriculography for the assessment of ejection fraction at this time.