Electrocardiographic Telemetry Research Articles

Abstract 14830: Digital Central Monitoring Units Reduce Telemetry Alert Burden and Improve Clinician Alert Response Metrics

Introduction: Cardiac electrocardiographic telemetry is guided by AHA Practice Standards and is associated with improved patient outcomes. Cardiac telemetry digital central monitoring units (dCMU) optimize telemetry performance by facilitating alert dispatches and providing processes for quality improvement. Hypothesis: Implementation of dCMU would result in a reduced number of alerts transmitted to bedside staff and improved alert management. Methods: From May 2022 to March 2023, alerts were collected and analyzed at 6 hospitals transitioned from standard telemetry practice to dCMU. Standard practice includes monitor technicians reviewing alerts and waveforms, ranking alerts and manually contacting clinicians. The dCMU platform organizes and ranks clinical alerts after which a CMU tech dispatches alerts to a mobile app. The bedside clinician receives the alert, patient data, and real time waveform for contextual analysis. The alert is marked “handled” when the provider accepts the message. If the message is not accepted, the alert enters an escalation pathway. The dCMU platform also contains performance analyzing software which guides process improvement. Results: Alert counts and characteristics were collected and analyzed during an 11-month period. Comparing a 30-day baseline period to the last 30-day post-implementation period, dispatched alerts to clinician devices decreased 35.5% - from 5,032 to 3,246 alerts per day and the rate of notifications handled by providers increased 88% - from 42% to 78.8% of all dispatched alerts (Figure 1). The total time that patients were in alert state decreased 32.4% - from 31,930 to 21,576 minutes per day. Conclusions: The introduction of dCMU structured and streamlined the telemetry dispatch process leading to reduced alert burden and improved bedside clinician alert handling. Further studies are necessary to determine the effects of dCMU dispatch control on patient outcomes compared to standard telemetry practice.

Seven day continuous ambulatory electrocardiographic telemetric study with pocket electrocardiographic recording device for detecting hydroxychloroquine induced arrhythmias.

Objective:The use of hydroxychloroquine (HCQ) for COVID-19 treatment and prophylaxis raised issues concerning its cardiac safety owing to the possibility of QT prolongation and arrhythmias. There was no study on long-term electrocardiographic telemetry monitoring of patients taking HCQ. We planned a continuous electrocardiographic Holter telemetry of these patients for 7 days.Material and Methods:Health care workers taking HCQ as pre exposure prophylaxis and patients on HCQ were monitored using seven day Holter electrocardiographic telemetry with continuous beat to beat analysis. Telemetry can instantly convey any arrhythmic event or significant QT prolongation to the medical faculty.Results:Twenty-five participants with a mean age of 42.4 ± 14.1 years were included in the study; 40% were females. Twenty percent of participants needed to stop HCQ. Four patients developed QT prolongation >500 ms and needed to stop HCQ, one patient had accelerated idioventricular rhythm and stopped treatment, and one had short episodes of atrial fibrillation. No malignant arrhythmia or ventricular arrhythmia, or torsade de pointis were noted. No episode of significant conduction disturbance and arrhythmic death was noted. Baseline mean QTc was 423.96 ± 32.18 ms, mean QTc corrected at 24 h was 438.93 ± 37.95, mean QTc was 451.879 ± 37.99 at 48 h, and change in baseline mean QTc to max QTc was 30.74 ± 21.75 ms at 48 h. All those who developed QTc prolongation >500 ms were greater than 50 years of age.Conclusion:Ambulatory telemetry ECG monitoring detects early QT prolongation, and stopping drugs prevents malignant arrhythmias. HCQ seems to have less risk of QT prolongation in young, healthy individuals.

Cardiomyocyte Deletion of Bmal1 Exacerbates QT- and RR-Interval Prolongation in Scn5a+/ΔKPQ Mice

Circadian rhythms are generated by cell autonomous circadian clocks that perform a ubiquitous cellular time-keeping function and cell type-specific functions important for normal physiology. Studies show inducing the deletion of the core circadian clock transcription factor Bmal1 in adult mouse cardiomyocytes disrupts cardiac circadian clock function, cardiac ion channel expression, slows heart rate, and prolongs the QT-interval at slow heart rates. This study determined how inducing the deletion of Bmal1 in adult cardiomyocytes impacted the in vivo electrophysiological phenotype of a knock-in mouse model for the arrhythmogenic long QT syndrome (Scn5a+/ΔKPQ). Electrocardiographic telemetry showed inducing the deletion of Bmal1 in the cardiomyocytes of mice with or without the ΔKPQ-Scn5a mutation increased the QT-interval at RR-intervals that were ≥130 ms. Inducing the deletion of Bmal1 in the cardiomyocytes of mice with or without the ΔKPQ-Scn5a mutation also increased the day/night rhythm-adjusted mean in the RR-interval, but it did not change the period, phase or amplitude. Compared to mice without the ΔKPQ-Scn5a mutation, mice with the ΔKPQ-Scn5a mutation had reduced heart rate variability (HRV) during the peak of the day/night rhythm in the RR-interval. Inducing the deletion of Bmal1 in cardiomyocytes did not affect HRV in mice without the ΔKPQ-Scn5a mutation, but it did increase HRV in mice with the ΔKPQ-Scn5a mutation. The data demonstrate that deleting Bmal1 in cardiomyocytes exacerbates QT- and RR-interval prolongation in mice with the ΔKPQ-Scn5a mutation.

Development and Validation of an Automated Algorithm to Detect Atrial Fibrillation Within Stored Intensive Care Unit Continuous Electrocardiographic Data: Observational Study.

BackgroundAtrial fibrillation (AF) is the most common arrhythmia during critical illness, representing a sepsis-defining cardiac dysfunction associated with adverse outcomes. Large burdens of premature beats and noisy signal during sepsis may pose unique challenges to automated AF detection.ObjectiveThe objective of this study is to develop and validate an automated algorithm to accurately identify AF within electronic health care data among critically ill patients with sepsis.MethodsThis is a retrospective cohort study of patients hospitalized with sepsis identified from Medical Information Mart for Intensive Care (MIMIC III) electronic health data with linked electrocardiographic (ECG) telemetry waveforms. Within 3 separate cohorts of 50 patients, we iteratively developed and validated an automated algorithm that identifies ECG signals, removes noise, and identifies irregular rhythm and premature beats in order to identify AF. We compared the automated algorithm to current methods of AF identification in large databases, including ICD-9 (International Classification of Diseases, 9th edition) codes and hourly nurse annotation of heart rhythm. Methods of AF identification were tested against gold-standard manual ECG review.ResultsAF detection algorithms that did not differentiate AF from premature atrial and ventricular beats performed modestly, with 76% (95% CI 61%-87%) accuracy. Performance improved (P=.02) with the addition of premature beat detection (validation set accuracy: 94% [95% CI 83%-99%]). Median time between automated and manual detection of AF onset was 30 minutes (25th-75th percentile 0-208 minutes). The accuracy of ICD-9 codes (68%; P=.002 vs automated algorithm) and nurse charting (80%; P=.02 vs algorithm) was lower than that of the automated algorithm.ConclusionsAn automated algorithm using telemetry ECG data can feasibly and accurately detect AF among critically ill patients with sepsis, and represents an improvement in AF detection within large databases.

Macrophage migration inhibitory factor increases atrial arrhythmogenesis through CD74 signaling

Macrophage migration inhibitory factor (MIF), a pleiotropic inflammatory cytokine, is highly expressed in patients with atrial fibrillation (AF). CD74 (major histocompatibility complex, class II invariant chain) is the main receptor for MIF. However, the role of the MIF/CD74 axis in atrial arrhythmogenesis is unclear. In this study, we investigated the effects of MIF/CD74 signaling on atrial electrophysiological characteristics and determined its underlying mechanisms. Confocal fluorescence microscopy, patch clamp, and western blot analysis were used to study calcium homeostasis, ionic currents, and calcium-related signaling in MIF-treated HL-1 atrial cardiomyocytes with or without anti-CD74 neutralized antibodies treatment. Furthermore, electrocardiographic telemetry recording and echocardiography were obtained from mice treated with MIF. Compared with controls, MIF-treated HL-1 myocytes had increased calcium transients, sarcoplasmic reticulum (SR) calcium content, Na+/Ca2+ exchanger (NCX) efflux rate, calcium leak, transient outward potassium current, and ultra-rapid delayed rectifier potassium current. Furthermore, MIF could induce expression of SR Ca2+ATPase, NCX, phosphorylation of ryanodine receptor 2 (RyR2), and activation of calcium/calmodulin kinase II (CaMKII) when compared with control cells. MIF-mediated electrical dysregulation and CaMKII-RyR2 signaling activation were attenuated through blocking of CD74. Moreover, MIF-injected mice had lesser left atrium fractional shortening, greater atrial fibrosis, and atrial ectopic beats than control (nonspecific immunoglobulin treated) or MIF combined with anti-CD74 neutralized antibody-treated mice. Consequently, our study on MIF/CD74 signaling has pointed out a new potential therapeutic intervention of AF patients with MIF elevation.

Usefulness of Trends in Continuous Electrocardiographic Telemetry Monitoring to Predict In-Hospital Cardiac Arrest

Survival from in-hospital cardiac arrest (IHCA) due to pulseless electrical activity/asystole remains poor. We aimed to evaluate whether electrocardiographic changes provide predictive information for risk of IHCA from pulseless electrical activity/asystole. We conducted a retrospective case-control study, utilizing continuous electrocardiographic data from case and control patients. We selected 3 consecutive 3-hour blocks (block 3, 2, and 1 in that order); block 1 immediately preceded cardiac arrest in cases, whereas block 1 was chosen at random in controls. In each block, we measured dominant positive and negative trends in electrocardiographic parameters, evaluated for arrhythmias, and compared these between consecutive blocks. We created random forest and logistic regression models, and tested them on differentiating case versus control patients (case block 1 vs control block 1), and temporal relation to cardiac arrest (case block 2 vs case block 1). Ninety-one cases (age 63.0 ± 17.6, 58% male) and 1,783 control patients (age 63.5 ± 14.8, 67% male) were evaluated. We found significant differences in electrocardiographic trends between case and control block 1, particularly in QRS duration, QTc, RR, and ST. New episodes of atrial fibrillation and bradyarrhythmias were more common before IHCA. The optimal model was the random forest, achieving an area under the curve of 0.829, 63.2% sensitivity, 94.6% specificity at differentiating case versus control block 1 on a validation set, and area under the curve 0.954, 91.2% sensitivity, 83.5% specificity at differentiating case block 1 versus case block 2. In conclusion, trends in electrocardiographic parameters during the 3-hour window immediately preceding IHCA differ significantly from other time periods, and provide robust predictive information.

Clinical Pearls

Complications of delirium are widely known and can contribute to significant morbidity and mortality. However, delirium is under-recognized and undetected in 30% to 75% of cases. Further, studies have shown that nurses have inadequate knowledge of delirium risk factors and consequences and that some nurses believe delirium screening is unnecessary.Blevins and colleagues tested the effectiveness of an educational intervention on nurses’ knowledge of delirium and delirium risk factors. The intervention included a video, didactic instruction, case study analyses, and bedside screening instruction with return demonstration. They found the following:Although further research on various instructional methods is needed to determine the best strategies, the authors recommend ongoing education to maintain accurate screening.See Article, pp 270–278Items that are often touched in the hospital setting may contain microbes that contribute to nosocomial infections. Most surfaces can be effectively disinfected following standards set by the manufacturer. However, items with complex, intricate surfaces are more difficult to clean and may serve as reservoirs for bacteria.Risteen and colleagues studied the effectiveness of 0.5% hydrogen peroxide wipes on blood pressure cuffs and electrocardiographic telemetry leads, as compared with the cleaning of hard, smooth surfaces. They found the following:The hydrogen peroxide wipes were adequate for blood pressure cuffs but not for telemetry leads. The authors advocate an emphasis on thorough cleaning of all surfaces, including ones that are smooth and hard.See Article, pp 322–327Mortality rates of adult patients in the intensive care unit (ICU) are high. Most families recover from their bereavement, but some experience complicated grief. Research on bereavement experiences has identified some family issues with the experience, but most studies were done outside of the United States and may present differences.Jones and colleagues interviewed families of patients who had died in the medical-surgical or cardiac ICU within the past 13 months. They found the following 3 main themes:Although bereavement care needs to be individualized, findings show that patients’ families would like support both during and after the ICU experience. The authors remind practitioners to be aware of the impact they have on patients’ families.See Article, pp 312–321Alcohol withdrawal syndrome (AWS) is a medical condition with significant symptoms. The 2 most commonly used AWS assessment tools are The Clinical Institute Withdrawal Assessment (CIWA-Ar) and the Minnesota Detoxification Scale (MINDS). The MINDS has been validated with patients in the intensive care unit (ICU) but the CIWA-Ar has not, and this has led to mismanagement of AWS treatment when transitioning a patient from the ICU to a non-ICU setting.Littlefield and colleagues compared the CIWA-Ar and a modified MINDS tool in order to compare the similarities and found the following:The authors state that the results of this study can advance the care of patients with AWS and be used to improve protocols for patients’ transition from the ICU to other hospital units.See Article, pp 280–286

Disinfection of Blood Pressure Cuffs and Electrocardiographic Telemetry Leads With 0.5% Hydrogen Peroxide Wipes.

Disinfection of frequently touched surfaces in the hospital is critical for providing safe care. Because of their complex intricate surfaces, blood pressure cuffs and electrocardiographic telemetry leads may be harder than other equipment to disinfect. To determine the effectiveness of 0.5% hydrogen peroxide wipes in cleaning and disinfecting inpatient hospital surfaces, including hook and loop (Velcro) fasteners of blood pressure cuffs and electrocardiographic telemetry leads. A prospective study of an inpatient telemetry unit was designed to measure the persistence of a UV indicator and the presence of bacterial colonization on electrocardiographic telemetry leads and blood pressure cuffs. Call buttons and patient trays were used as control surfaces, because they are often touched but are easy to disinfect via standard practices. A total of 392 samples were collected between July 11 and August 3, 2016, and cultured for microorganisms. Among the cultures, 247 (63%) had at least 1 colony-forming unit. After adjustments in a multivariable analysis, odds of a contaminated surface (≥ 10 colony-forming units) after final cleaning with 0.5% hydrogen peroxide wipes were 3.70 times greater for patient trays than for blood pressure cuffs (P = .03) and 3.80 times greater for telemetry leads than for blood pressure cuffs (P = .04). The UV indicator persisted longer on blood pressure cuffs and telemetry leads than on patient trays or call buttons (P < .001). Wipes with 0.5% hydrogen peroxide adequately disinfect blood pressure cuffs but not telemetry leads.

Preservation of conductive propagation after surgical repair of cardiac defects with a bio-engineered conductive patch

Both stable and biodegradable biomaterials have been used to surgically repair congenital cardiac defects. However, neither type of biomaterial can conduct electrical activity. We evaluated the conductivity and efficacy of a newly synthesized conductive polypyrrole-chitosan (Ppy+Chi) gelfoam patch to support cardiomyocyte (CM) viability and function in vitro and to surgically repair a cardiac defect in vivo. Ppy+Chi was incorporated into gelfoam (Gel) to form a 3-dimensional conductive patch. In vitro, patch characteristics were evaluated and biocompatibility and bioconductivity were investigated by culturing neonatal rat CMs on the patches. In vivo, a full-thickness right ventricular outflow tract defect was created in rats and the patches were implanted. Four weeks after patch repair, cardiac electrical activation and conduction velocity were evaluated using an optical mapping system. In vitro, the Ppy+Chi+Gel patch had a higher mean breaking stress than the Gel or Chi+Gel patches, and the highest conductivity. None of the patches altered cell growth. The Ca2+ transient velocity of CMs cultured on the Ppy+Chi+Gel patch was 2.5-fold higher than that of CMs cultured on the Gel or Chi+Gel patches. In vivo, optical mapping at 4 weeks post-implantation demonstrated that Ppy+Chi+Gel patch-implanted hearts had faster conduction velocities, as measured on the epicardial surface. Continuous electrocardiographic telemetry did not reveal any pathologic arrhythmias after patch implantation. Ex-vivo patch conductivity testing also revealed that the Ppy+Chi+Gel patch was more conductive than the Gel and Chi+Gel patches. The Ppy+Chi+Gel patch was biocompatible, safe and conductive, making it an attractive candidate for a new biomaterial platform for cardiac surgical repair to preserve synchronous ventricular contraction.

Development of alternative diagnostic feature system in the cardiology decision support systems

The trend towards an increase in the production of Ukrainian digital electrocardiographic telemetry systems such as transtelephonic digital 12-channel electrocardiograph complex “Telecard” identified the need to create intelligent automated cardiac decision support systems. The basis of these systems is the morphologic analysis of electrocardiograms, which represent biomedical signals with locally concentrated features. The system of alternative diagnostic features based on the method proposed by the authors of the morphological analysis of biomedical signals with locally concentrated features to provide additional graphical information in the diagnosis of one of the most common cardiac arrhythmias - ventricular arrhythmia is developed. Representation of the electrocardiogram in two-dimensional space of alternative features, as well as hodograph is proposed. Differences between the ECG-hodographs for normal ECG and ECG with different arrhythmias of right and left ventricles, as well as multifocal ventricular arrhythmia are analyzed. It was found that a graphical representation of an electrocardiogram in the alternative feature space allows the physician to visually perform the classification of different types of ventricular arrhythmia, which in combination with the classical analysis of ECG on the time axis increases the reliability of diagnostics.

The cardiomyocyte molecular clock regulates the circadian expression of Kcnh2 and contributes to ventricular repolarization.

Sudden cardiac death (SCD) follows a diurnal variation. Data suggest the timing of SCD is influenced by circadian (~24-hour) changes in neurohumoral and cardiomyocyte-specific regulation of the heart's electrical properties. The basic helix-loop-helix transcription factors brain muscle arnt-like1 (BMAL1) and circadian locomotor output control kaput (CLOCK) coordinate the circadian expression of select genes. We sought to test whether Bmal1 expression in cardiomyocytes contributes to K(+) channel expression and diurnal changes in ventricular repolarization. We used transgenic mice that allow for the inducible cardiomyocyte-specific deletion of Bmal1 (iCSΔBmal1(-/-)). We used quantitative polymerase chain reaction, voltage clamping, promoter-reporter bioluminescence assays, and electrocardiographic telemetry. Although several K(+) channel gene transcripts were downregulated in iCSΔBmal1(-/-)mouse hearts, only Kcnh2 exhibited a robust circadian pattern of expression that was disrupted in iCSΔBmal1(-/-) hearts. Kcnh2 underlies the rapidly activating delayed-rectifier K(+) current, and the rapidly activating delayed-rectifier K(+) current recorded from iCSΔBmal1(-/-) ventricular cardiomyocytes was ~50% smaller than control ventricular myocytes. Promoter-reporter assays demonstrated that the human Kcnh2 promoter is transactivated by the coexpression of BMAL1 and CLOCK. Electrocardiographic analysis showed that iCSΔBmal1(-/-) mice developed a prolongation in the heart rate-corrected QT interval during the light (resting) phase. This was secondary to an augmented circadian rhythm in the uncorrected QT interval without a corresponding change in the RR interval. The molecular clock in the heart regulates the circadian expression of Kcnh2, modifies K(+) channel gene expression, and is important for normal ventricular repolarization. Disruption of the cardiomyocyte circadian clock mechanism likely unmasks diurnal changes in ventricular repolarization that could contribute to an increased risk of cardiac arrhythmias/SCD.

Renal dysfunction and the risk of postoperative atrial fibrillation after cardiac surgery: role beyond the CHA2DS2-VASc score.

To investigate whether renal dysfunction is a useful predictor of postoperative atrial fibrillation (POAF) after cardiac surgery. We also aimed to determine whether the addition of renal dysfunction into the scoring system could improve diagnostic accuracy of the CHA2DS2-VASc score to predict POAF. The study prospectively enrolled 350 consecutive patients who underwent cardiac surgery. Echocardiography was performed before cardiac surgery. Renal dysfunction was defined as estimated glomerular filtration rate < 60 mL min(-1) 1.73 m(-2). All patients were monitored with continuous electrocardiographic telemetry for the occurrence of POAF until the day of hospital dismissal. Postoperative atrial fibrillation occurred in 103 of 350 patients (29%). Patients with POAF was associated with longer intensive care unit stay compared with those without POAF (3.7 ± 2.2 vs. 3.1 ± 1.4 days, P = 0.002). Both the CHA2DS2-VASc score and renal dysfunction were independent predictors of POAF in multivariate analysis. Renal dysfunction can further stratify patients with a CHA2DS2-VASc score of 0 or 1 into two groups with different POAF rates (3.1% vs. 68.8%, P < 0.001). A new scoring system (R-CHA2DS2-VASc score) derived by assigning an additional point representing renal dysfunction to the CHA2DS2-VASc score could improve its predictive accuracy. The area under the receiver operating characteristic curve increased from 0.68 to 0.71 (P < 0.001). Furthermore, the rate of left ventricular diastolic dysfunction also increased with increasing renal dysfunction. Renal dysfunction, associated with left ventricular diastolic dysfunction, was a significant risk factor for POAF after cardiac surgery and may improve the diagnostic accuracy of the CHA2DS2-VASc score.

Prediction of Atrial Fibrillation After Off-Pump Coronary Artery Bypass Grafting Using Preoperative Total Atrial Conduction Time Determined on Tissue Doppler Imaging

Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery and results in increased health-care utilization. This study identified new transthoracic echocardiographic predictors of POAF using an index of the total atrial conduction time derived on tissue Doppler imaging (PA-TDI duration) in patients undergoing off-pump coronary artery bypass grafting (OPCAB). A total of 88 patients undergoing isolated OPCAB were enrolled. They were examined preoperatively on transthoracic echocardiography with tissue Doppler evaluations and monitored postoperatively with continuous electrocardiographic telemetry for 7 days. POAF occurred in 35 patients (39.8%). Patients with POAF had a significantly longer duration of hospital stay than those without (44.9±6.2 vs. 37.3±3.3 days, P=0.04). Multivariate analysis showed that PA-TDI duration (odds ratio [OR], 1.11; 95% confidence interval [CI]: 1.06-1.16; P=0.0001) and left atrial volume index (LAVI; OR, 1.11; 95% CI: 1.02-1.20; P=0.01) were independent predictors of POAF. Moreover, PA-TDI duration was more reliable, given an area under the receiver operating characteristic curve of 0.85 (sensitivity, 74.3%; specificity, 86.8%). PA-TDI duration was an independent predictor of POAF following OPCAB. Awareness of risk of POAF may lead to the prevention of POAF, a rapid response to POAF, shortened hospital stay, and improved prognosis.

Preoperative Tissue Doppler Imaging-Derived Atrial Conduction Time Can Predict Postoperative Atrial Fibrillation in Patients Undergoing Aortic Valve Replacement for Aortic Valve Stenosis

Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery and may result in stroke or heart failure and poor prognosis. This study aimed to evaluate a novel index of total atrial conduction time derived from the P-wave onset (lead II) to the peak A' wave on tissue Doppler imaging (PA-TDI duration). The PA-TDI duration was compared with previously reported predictors of POAF, and the optimal cutoff value of PA-DTI was calculated in patients undergoing aortic valve replacement (AVR) for AV stenosis (AS). METHODS AND RESULTS: We enrolled 63 patients undergoing isolated AVR. They underwent transthoracic echocardiography with TDI preoperatively and were monitored postoperatively with continuous electrocardiographic telemetry for 7 days. The hospital stay was significantly longer in the 41 patients with POAF than in the 22 without POAF (33.8±19.7 vs. 24.1±8.1 days, P=0.03). Multivariate analysis revealed that PA-TDI duration (odds ratio [OR], 1.07; 95% confidence interval [CI], 1.02-1.13; P=0.0072) and age (OR, 1.14; CI, 1.03-1.28; P=0.016) were significant independent predictors of POAF. Receiver-operating characteristic curve analysis showed the optimal cutoff values of PA-TDI duration and age were 147.3 ms and 74 years, respectively. The PA-TDI duration was an independent predictor of POAF after AVR for AS. Patients with PA-TDI duration >147 ms should be considered high risk and treated appropriately to improve outcomes.

Microbial Colonization of Electrocardiographic Telemetry Systems Before and After Cleaning

Nosocomial infections caused by multidrug-resistant organisms are commonly associated with longer hospital stays up to 12 to 18 days and annual estimated costs of $5.7 billion to $6.8 billion. One common mode of transmission is cross-contamination between patients and providers via surface contaminants on devices such as telemetry systems. To determine the effect of a cleaning protocol on colonization of surface contaminants on electrocardiographic telemetry systems in 4 cardiovascular step-down units and to compare colonization in medical vs surgical units. A prospective, randomized, case-controlled study (the Descriptive Evaluation of Electrocardiographic Telemetry Pathogens [DEET] study) was designed to evaluate microbial colonization on telemetry systems before and after cleaning with sodium hypochlorite wipes. Each randomly selected telemetry system served as its own control. Nurses used a standardized culture technique recommended by personnel in infection control. Colonization before and after cleaning was analyzed by using the McNemar test and frequency tables. A standard cost-comparison analysis was conducted. A total of 30 telemetry systems in medical units and 29 in surgical units were evaluated; 41 telemetry systems (69%) were colonized before the intervention, and 14 (24%) were colonized after it (P < .001). Before cleaning, surface organisms were present in 14 instances (35%) in surgical units and in 27 instances (66%) in medical units (P < .001). The cleaning strategy was cost-effective. The cleaning intervention was effective, and cost-comparison analysis supported implementing a cleaning strategy for reusable leads rather than investing in disposable leads.

Interference of Cardiac Pacemaker and Implantable Cardioverter-Defibrillator Activity During Electronic Dental Device Use

The authors conducted a study to determine if electromagnetic interference of cardiac pacemaker and implantable cardioverter-defibrillator (ICD) activity occurs during the operation of electronic dental devices. The authors tested nine electronic dental devices in vitro to assess their ability to interfere with the function of two pacemakers and two ICDs as determined by electrocardiographic telemetry. The pacing activity of both pacemakers and the dual-chamber ICD were inhibited during operation of the battery-operated composite curing light at between 2 and 10 centimeters from the generator or leads. The use of the ultrasonic scaler interfered with the pacing activity of the dual-chamber pacemaker at between 17 and 23 cm from the generator or leads, the single-chamber pacemaker at 15 cm from the generator or leads and both ICDs at 7 cm from the leads. The operation of the ultrasonic cleaning system interfered with the activity of the dual-chamber pacemaker at between 15 and 23 cm from the generator or leads, and of the single-chamber pacemaker at 12 cm. Operation of the electric toothbrush, electrosurgical unit, electric pulp tester, high- and low-speed handpieces, and an amalgamator did not alter pacing function. Select electronic dental devices interfere with pacemakers' and ICDs' sensing and pacing activity in vitro. Use of the ultrasonic scaler, ultrasonic cleaning system and battery-operated composite curing light may produce deleterious effects in patients who have pacemakers or ICDs.

Abrupt Termination of an Ethanol Regimen Provokes Ventricular Arrhythmia and Enhances Susceptibility to the Arrhythmogenic Effects of Epinephrine in Rats

Pathologists examining victims of sudden unexpected death encounter alcoholics more often than expected; alcohol may play a role in sudden arrhythmic death. Here we determine whether a pattern of alcohol consumption, chronic ethanol intake, and withdrawal increases the incidence of malignant ventricular arrhythmia and modulates susceptibility to the arrhythmogenic potential of sympathetic stimulation from an epinephrine test in rats. Male Wistar rats were treated with a continuous ethanol liquid diet for 7 weeks, and then subjected to 1-day withdrawal or 21-day abstinence. Ventricular ectopy was evaluated by 24-hour electrocardiographic telemetry recording; whole-body sympathetic activation, cardiac sympathovagal balance, and susceptibility to ventricular arrhythmia induced by sympathetic stimulation were evaluated based on blood noradrenalin metabolite concentrations, heart rate variability, and a 3-step epinephrine test. Ventricular arrhythmia and related death were observed only in rats at 1 day of withdrawal, but not in nonalcoholic, continuous ethanol intake or 21-day abstinence rats. One-day withdrawal after a 7-week continuous ethanol regimen elevated circulating noradrenalin metabolite levels and induced cardiac sympathovagal imbalance. Deaths related to the epinephrine test and ventricular arrhythmia induced by low doses of epinephrine were observed only in 1-day withdrawal rats. However, all anomalies were normalized by 21-day abstinence. Abrupt termination of a 7-week continuous ethanol regimen is sufficient to enhance the whole-body sympathetic activation and cardiac sympathovagal imbalance that contribute to ventricular arrhythmia and sudden death in alcoholic rats. Those providing medical care for alcoholics, including in cases of legal imprisonment, should be aware of the possibility of enhanced susceptibility to sudden arrhythmic death due to the abrupt termination of a chronic ethanol regimen.

Relationship Between Integrated Backscatter and Atrial Fibrosis in Patients with and Without Atrial Fibrillation Who Are Undergoing Coronary Bypass Surgery

The purpose of this study was to investigate the relationship between the integrated backscatter (IBS) and atrial fibrosis, with and without atrial fibrillation (AF), in patients who are undergoing coronary bypass grafting (CABG). A total of 74 patients (18 preoperative AF, 56 sinus rhythm [SR]) with coronary artery disease undergoing CABG were included. The IBS of the left atrium (LA) posterior wall was acquired from transthoracic echocardiographic examination before surgery. Samples from the LA appendage were collected after opening the pericardium and quantitative assessment of atrial fibrosis was performed with collagen volume fraction (CVF). Postoperative AF was monitored with electrocardiographic telemetry in-hospital. There was a positive relationship between age, IBS of the left atrial posterior wall indexed by pericardium (IBS%), and CVF by multivariate linear regression analysis (r = 0.612, p = 0.034; r = 0.887, p < 0.001 respectively). The value of IBS%, LA dimension (LAD), and CVF values were higher in patients with preoperative AF than in patients with preoperative SR (p < 0.001, p < 0.01, p < 0.001, respectively). The value of age, IBS%, and CVF in patients with postoperative AF were higher than in patients without postoperative AF (p = 0.029, p < 0.001, p = 0.001 respectively). IBS of the LA posterior wall indexed by pericardium provides an objective quantitative measure of atrial fibrosis and correlates with postoperative AF in patients undergoing CABG surgery.

Seizure-like Activity and Other Adverse Events While Using Propofol: A Retrospective Observational Study of 38,575 Sequential Endoscopies in an Outpatient Gastrointestinal Endoscopy Center

Purpose: To examine the occurrence of seizure-like activity and other adverse events during propofol-mediated gastrointestinal endoscopies. Background: Propofol is a fast acting hypnotic, with action on GABA receptors. In recent years propofol has increasingly been administered for sedation during endoscopic procedures. Multiple studies have identified the propofol-related cardiopulmonary complications. More recently there have been case reports describing seizure like activity (SLA) in propofol-mediated sedation. However, reports of SLA during gastrointestinal endoscopy are scarce. Methods: This is a retrospective observational study from a single outpatient practice comprised of 18 U.S. gastrointestinal endoscopists. Data was collected from January 2005 to May 2007. A total of 38,575 sequential endoscopic procedures were performed using propofol, administered by nurse anesthetists. Procedures included both, esophagogastroduodenoscopies and colonoscopies. ASA classes for patients undergoing endoscopy ranged from I-III. Standard monitoring with pulse oximetry, automated sphygmomanometry, and electrocardiographic telemetry was performed. All adverse events related to propofol administration were recorded. Results: The number of propofol administered endoscopic procedures performed over a twenty-nine month period was 38,575, with a total of 107 (0.277%) anesthesia related complications. A total of 71 (0.18%) cardiopulmonary complications: 5 (0.013%) apnea/hypoxia, 23 (0.06%) possible aspirations, 11 (0.029%) laryngospasms, 2 (0.005%) hypotension 10 (0.026%) hypertension episodes, 17 (0.044%) arrhythmias, and 3 (0.0078% chest pain). SLA was identified in 1 (0.0026%) patient. A sample of 190 patients over a five-day consecutive period was evaluated to calculate the mean dose of propofol given during procedures. The mean dose of propofol was 254 ± 78 mg (range of 60–600 mg). The one patient who had SLA received a total of 150 mg. The SLA occurred during induction with propofol, the patient remained conscious through the episode. Once resolved, the procedure was completed without further incident. Conclusion: Propofol can be safely administered for gastrointestinal endoscopy. Seizure like activity is an extremely rare occurrence when utilizing propofol for sedation in patients undergoing gastrointestinal endoscopy, irrespective of dosage.

Rapid Analysis of Electrocardiograms: A Self-Study Program, 3rd Edition

Rapid Analysis of Electrocardiograms: A Self-Study Program, 3rd Edition Author: STEIN, Emanuel, MD, MPH, FACP (Eastern Virginia Medical School) Bibliographic Data: (ISBN: 0-683-30656-1, Lippincott Williams & Wilkins, 1999, $32.95) 390 pages, soft cover Audiences: Cardiology Residents, Medical Students Subjects: Cardiology, Coronary Care Other Info: The book contains black-and-white illustrations. DESCRIPTION: This is a description of basic electrocardiography written for all members of the health profession. It is divided into three sections, one on basic electrocardiography, a self-assessment section, and an appendix. PURPOSE: The purpose is to provide a firm foundation in the interpretation of electrocardiography. This is a very important concept since electrocardiography is such a common test and is used widely. AUDIENCE: The author has written this book for beginners in electrocardiography whether they be medical students, medical residents, nurses, or electrocardiographic telemetry technicians. This is the author’s third book in the area. FEATURES: Basics in electrocardiography are covered. Each step is well illustrated and is followed by two questions for the student. Calculation of QRS axis is particularly well written. There is a significant addition to earlier editions in the self-assessment electrocardiographic text. This is based on the American College of Cardiology certification examination in electrocardiography. ASSESSMENT: This book is recommended for beginners in electrocardiography. It is well written, has many clear illustrations, and a good self-assessment electrocardiographic test. There are also further comments in the appendix regarding electrocardiographic concepts such as aberrancy, re-entry, concealed conduction, the rule of bigeminy, and others. The 57 references listed are some of the vintage papers in electrocardiography. SCORE: Weighted Numerical Score: 97 - *****