Critical Arrhythmias Research Articles

Detection of Heart Diseases Using Deep Learning Techniques

Electrocardiography is an effective tool for detecting heart diseases or predicting heart diseases,and previous researchers have approved it as an effective tool in diagnosis. This early diagnosis'sessential benefit is reducing deaths due to heart disease because the heart is the most criticalpart of the human body. From this Starting point, this paper used electrocardiography todiagnose and predict heart disease. A system that supports deep learning by using ConvolutionalNeural Network and the use of the most critical global data set approved by previous researcherswas proposed to diagnose or predict the four most critical pathological conditions, namely (STTabnormalities, myocardial infarction (MI), arrhythmias, and Conduction disturbances andabnormalities) The proposed system goes through three primary stages (processing,classification, and prediction), where CNN deep learning algorithms of the design the proposedsystem. The data set was used. PTB-XL for calculating healthy and infected samples forcomplete system training, testing, and prediction. The proposed system achieved good resultswith a sensitivity of 72.3%, a specificity of 73.90%, an accuracy of 91.33%, an accuracy of88.69%, and an f1 score of 92.51%.

Perioperative multivessel coronary artery spasm and cardiac arrest after cardiac surgery.

Postoperative coronary artery spasm, a rare but potentially fatal complication following cardiac surgery, warrants significant attention. This report discusses a 64-year-old male who suffered a severe coronary artery spasm leading to cardiac arrest following surgery. Initially stable, the patient rapidly developed critical ventricular arrhythmias and hypotension, resulting in cardiac arrest 4 h post-surgery. Emergency coronary angiography revealed extensive spasms, successfully managed with intracoronary nitroglycerine. This case stresses prompt recognition and management of coronary artery spasm after non-coronary cardiac procedures, underscoring coronary angiography's vital role in diagnosis and treatment.

Possible Mechanisms for Adverse Cardiac Events Caused by Exercise-Induced Hypertension in Long-Distance Middle-Aged Runners: A Review.

Sudden cardiac death (SCD) is rare among athletes. However, hypertrophic cardiomyopathy is the leading cause of SCD among those <35 years of age. Meanwhile, coronary artery disease (CAD) is the primary SCD cause among those ≥35 years of age. CAD-induced plaque ruptures are believed to be a significant cause of cardiovascular diseases in middle-aged individuals who participate in extreme long-distance running activities such as marathons. A total of 1970 articles related to EIH were identified using search terms. Out of these, 1946 studies were excluded for reasons such as arterial hypertension, exercise-induced pulmonary hypertension, the absence of exercise stress testing (EST), and a lack of relevance to EIH. The study analyzed 24 studies related to both long-distance runners with exercise-induced hypertension (EIH) and the general public. Among these, 11 studies were quasi-experimentally designed studies used in randomized controlled trials (RCTs) on long-distance runners with EIH. Additionally, 12 studies utilized cohort designs, and one study with a quasi-experimental design was conducted among the general population. Recent studies suggest that an imbalance between oxygen demand and supply due to ventricular hypertrophy may be the actual cause of cardiovascular disease, regardless of CAD. Exercising excessively over an extended period can reduce endothelial function and increase arterial stiffness, which in turn increases afterload and leads to an excessive increase in blood pressure during exercise. Exercise-induced hypertension (EIH), which increases the morbidity rate of resting hypertension and is a risk factor for cardio-cerebro-vascular diseases, is more prevalent in middle-aged long-distance runners than in runners from other age groups, and it increases the prevalence of critical arrhythmias, such as atrial fibrillation or ventricular arrhythmias. EIH is associated with angiotensin II activity, and angiotensin II receptor blockers show promising effects in middle-aged runners. Further, guidelines for preventing excessive participation in races and restricting exercise intensity and frequency would be useful. This review identifies EIH as a potential risk factor for cardiovascular diseases and describes how EIH induces SCD.

Detection of Ventricular Fibrillation Using Ensemble Empirical Mode Decomposition of ECG Signals

Ventricular fibrillation (VF) is a critical ventricular arrhythmia with severe consequences. Due to the severity of VF, it urgently requires a rapid and accurate detection of abnormal patterns in ECG signals. Here, we present an efficient method to detect abnormal electrocardiogram (ECG) signals associated with VF by measuring orthogonality between intrinsic mode functions (IMFs) derived from a data-driven decomposition method, namely, ensemble empirical mode decomposition (EEMD). The proposed method incorporates the decomposition of the ECG signal into its IMFs using EEMD, followed by the computation of the angles between subsequent IMFs, especially low-order IMFs, as the features to discriminate normal and abnormal ECG patterns. The proposed method was validated through experiments using a public MIT-BIH ECG dataset for its effectiveness in detecting VF ECG signals compared to conventional methods. The proposed method achieves a sensitivity of 99.22%, a specificity of 99.37%, and an accuracy of 99.28% with a 3 s ECG window and a support vector machine (SVM) with a linear kernel, which performs better than existing VF detection methods. The capability of the proposed method can provide a perspective approach for the real-time and practical computer-aided diagnosis of VF.

Prediction and Analysis of Heart Diseases Using Heterogeneous Computing Platform

The work in this paper helps study cardiac rhythms and the electrical activity of the heart for two of the most critical cardiac arrhythmias. Various consumer devices exist, but implementation of an appropriate device at a certain position on the body at a certain pressure point containing an enormous number of blood vessels and developing filtering techniques for the most accurate signal extraction from the heart is a challenging task. In this paper, we provide evidence of prediction and analysis of Atrial Fibrillation (AF) and Ventricular Fibrillation (VF). Long-term monitoring of diseases such as AF and VF occurrences is very important, as these will lead to occurrence of ischemic stroke, cardiac arrest and complete heart failure. The AF and VF signal classification accuracy are much higher when processed on a Graphics Processor Unit (GPU) than Central Processing Unit (CPU) or traditional Holter machines. The classifier COMMA-Z filter is applied to the highly-sensitive industry certified Bio PPG sensor placed at the earlobe and computed on GPU.

An intelligent health monitoring and diagnosis system based on the internet of things and fuzzy logic for cardiac arrhythmia COVID-19 patients

Background:During the COVID-19 pandemic, there is a global demand for intelligent health surveillance and diagnosis systems for patients with critical conditions, particularly those with severe heart diseases. Sophisticated measurement tools are used in hospitals worldwide to identify serious heart conditions. However, these tools need the face-to-face involvement of healthcare experts to identify cardiac problems. Objective:To design and implement an intelligent health monitoring and diagnosis system for critical cardiac arrhythmia COVID-19 patients. Methodology:We use artificial intelligence tools divided into two parts: (i) IoT-based health monitoring; and (ii) fuzzy logic-based medical diagnosis. The intelligent diagnosis of heart conditions and IoT-based health surveillance by doctors is offered to critical COVID-19 patients or isolated in remote locations. Sensors, cloud storage, as well as a global system for mobile texts and emails for communication with doctors in case of emergency are employed in our proposal. Results:Our implemented system favors remote areas and isolated critical patients. This system utilizes an intelligent algorithm that employs an ECG signal pre-processed by moving through six digital filters. Then, based on the processed results, features are computed and assessed. The intelligent fuzzy system can make an autonomous diagnosis and has enough information to avoid human intervention. The algorithm is trained using ECG data from the MIT-BIH database and achieves high accuracy. In real-time validation, the fuzzy algorithm obtained almost 100% accuracy for all experiments. Conclusion:Our intelligent system can be helpful in many situations, but it is particularly beneficial for isolated COVID-19 patients who have critical heart arrhythmia and must receive intensive care.

Arrhythmia Assessment With 30-day MCT Patch Challenges Traditional Holter Monitoring

<h3>Introduction</h3> : Delayed diagnosis of episodic and asymptomatic arrhythmias can lead to adverse outcomes, especially for patients in the outpatient setting. Ambulatory Holter monitoring has been a cornerstone for diagnosing arrhythmias. While a traditional Holter records ECG signal for 24-48 hrs, the mobile cardiac telemetry (MCT) patch allows real-time ECG monitoring for up to 30 days. An MCT patch provides the ability to analyze long-term ECG data in real-time for timely and improved diagnosis. <h3>Objective</h3> : This study aims to identify if cardiac monitoring with a 30-day MCT patch provides better patient outcome than with the 24-hr Holter. To do so, we compared the arrhythmia and ectopy diagnostic yield of both modalities. <h3>Methods</h3> : A retrospective study was designed to analyze data recorded from 14,514 patients (male-43%, female-57%, median age-64 years) who were prescribed to be monitored with Zywie ECG monitors (Zywie, Inc., Georgia). The mean ECG analyzable time from 12,974 patients who used Holter and 1,540 patients who used MCT patch was 18.60±1.07 hrs and 28.2±2.4 days, respectively. We evaluated data to find the incidences of ectopic beats, including premature atrial contraction (PAC) and premature ventricular contraction (PVC), and any of 5 arrhythmias, including, sinus bradycardia (SB), sinus tachycardia (ST), atrial fibrillation (AF), pause, and ventricular tachycardia (VT). <h3>Results</h3> : Fig.1 suggests that the mean arrhythmia diagnostic yield of 38.1% in 30-day MCT studies is significantly different from 29.1% in 24-hr Holter studies (<i>p< 0.001</i>). We also analyzed the dataset to identify patients in which at least one arrhythmia was identified excluding SB and ST events. We identified 25% critical arrhythmias (excluding SB and ST) in patients with MCT patches in contrast to 9.6% in Holter. Fig. 2 shows that PVC beats were identified in 85.9% and 65.7%, whereas PAC beats in 92.3% and 78.2% of MCT and Holter studies, respectively. <h3>Conclusion</h3> : Results demonstrate that 30-day monitoring with MCT patch provides a better diagnostic yield than 24-hr Holter monitoring. Timely diagnosis with MCT patch can aid in early therapeutic intervention resulting in better patient care.

VENTRICULAR TACHYCARDIA ELECTRICAL STORM AS A MANIFESTATION OF REVERSE VARIANT TAKOTSUBO CARDIOMYOPATHY

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Takotsubo cardiomyopathy (TTC) is a syndrome with transient systolic dysfunction in the absence of obstructive coronary arteries with the reverse variant being a rare entity (1,2). Here, we report a case of reverse TTC presenting with monomorphic ventricular tachycardia (VT) electrical storm. CASE PRESENTATION: A 76 year-old female with a history of recently diagnosed Stage IIIB lung adenocarcinoma presented to the emergency room with shortness of breath. On presentation, her vitals were: BP 134/82, pulse 120 beats/min, SPO2 93% in room air. Initial EKG showed no significant ST-T wave changes and normal QTc. Labs were significant for uptrending troponin from 0.8 to 4 ng/mL. Aspirin and heparin infusion were started for possible NSTEMI with a plan for catheterization. That night, she developed unstable, monomorphic VT (Figure 1). Consecutive synchronized cardioversions and amiodarone boluses were unsuccessful. Patient's VT terminated with repeated boluses of lidocaine followed by lidocaine infusion. Stat echocardiogram showed an ejection fraction of 25-30% with anterior and anteroseptal hypokinesis. Emergency cardiac catheterization revealed non-obstructive coronary arteries with akinesis of the basal wall and sparing of the apex suggesting reverse TTC (Figure 2). She was transferred to the critical care unit where she was transitioned to amiodarone infusion with no further VT episodes and was initiated on guideline-directed medical therapy. DISCUSSION: TTC usually occurs due to a surge of catecholamines leading to myocardial damage. The typical variant demonstrates apical ballooning with basal hypokinesis. Rarely, there may be basal hypokinesis with apical sparing, the reverse variant (2). Arrhythmias are uncommon in typical TTC and prior studies have indicated a low incidence of VT (3.2%) (3). There is sparse literature describing the incidence of VT or VT storm in the reverse variant. One of the postulated mechanisms for VT in TTC is transient QTc prolongation, however this remains controversial. (3). The incidence of arrhythmias is thought to be more prevalent during the acute phase leading to increased in-hospital mortality (3). Additionally, it remains uncertain whether prophylactic antiarrhythmics are beneficial in this population subset. Further studies are warranted to understand which variants of TTC develop critical arrhythmias. CONCLUSIONS: Reverse variant is a rare subset of TTC which can present with critical arrhythmias including VT storm. Awareness of this manifestation can help clinicians with early recognition and management of these critical arrhythmias. REFERENCE #1: Bybee KA., Prasad A. Stress-related cardiomyopathy syndromes. Circulation 2008;118(4):397–409. Doi: 10.1161/CIRCULATIONAHA.106.677625. REFERENCE #2: Templin C., Ghadri JR., Diekmann J., et al. Clinical Features and Outcomes of Takotsubo (Stress) Cardiomyopathy. New England Journal of Medicine 2015;373(10):929–38. Doi: 10.1056/NEJMoa1406761. REFERENCE #3: Pant S, Deshmukh A, Mehta K, et al. Burden of arrhythmias in patients with Takotsubo Cardiomyopathy (Apical Ballooning Syndrome). International Journal of Cardiology [Internet] 2013;170(1):64–68. Available from: https://doi.org/10.1016/j.ijcard.2013.10.041 DISCLOSURES: No relevant relationships by Anneka Hutton, source=Web Response No relevant relationships by Gagan Neupane, source=Web Response No relevant relationships by Enoemem Okpokpo, source=Web Response No relevant relationships by Bharadwaj Satyavolu, source=Web Response No relevant relationships by Raksha Sharma, source=Web Response No relevant relationships by Tracey Topacio, source=Web Response

Effect of Remote Cardiac Monitoring System Design on Response Time to Critical Arrhythmias.

In many hospitals across the country, electrocardiograms of multiple at-risk patients are monitored remotely by telemetry monitor watchers in a central location. However, there is limited evidence regarding best practices for designing these cardiac monitoring systems to ensure prompt detection and response to life-threatening events. To identify factors that may affect monitoring efficiency, we simulated critical arrhythmias in inpatient units with different monitoring systems and compared their efficiency in communicating the arrhythmias to a first responder. This was a multicenter cross-sectional in situ simulation study. Simulation participants were monitor watchers and first responders (usually nurses) in 2 inpatient units in each of 3 hospitals. Manipulated variables included: (1) number of communication nodes between monitor watchers and first responders; (2) central monitoring station location-on or off the patient care unit; (3) monitor watchers' workload; (4) nurses' workload; and (5) participants' experience. We performed 62 arrhythmia simulations to measure response times of monitor watchers and 128 arrhythmia simulations to measure response times in patient care units. We found that systems in which an intermediary between monitor watchers and nurses communicated critical events had faster response times to simulated arrhythmias than systems in which monitor watchers communicated directly with nurses. Responses were also faster in units colocated with central monitoring stations than in those located remotely. As the perceived workload of nurses increased, response latency also increased. Experience did not affect response times. Although limited in our ability to isolate the effects of these factors from extraneous factors on central monitoring system efficiency, our study provides a roadmap for using in situ arrhythmia simulations to assess and improve monitoring performance.

Enhanced detection of cardiac arrhythmias utilizing 14-day continuous ECG patch monitoring

BackgroundTo evaluate the performance of a single‑lead, 14-day continuous electrocardiogram (ECG) patch for the detection of arrhythmias compared to conventional 24-h monitoring. MethodsThis prospective clinical trial enrolled patients suspected of arrhythmias but not diagnosed by 12‑lead ECGs. Each patient underwent a 24-h Holter and 14-day ECG patch simultaneously. Seven types of arrhythmias were classified: supraventricular tachycardia (SVT, repetitive atrial beats >4 beats), irregular SVT without P wave (>4 beats), AF/AFL (irregular SVT without P wave ≥30 s), pause ≥3 s, atrioventricular block (AVB; Mobitz type II, third-degree, two to one or high degree AVB), ventricular tachycardia (VT), and polymorphic VT. ResultsA total of 158 patients were recruited (mean wear time:12.3 ± 3.2 days). The overall arrhythmia detection rate was higher with 14-day ECG patches (59.5%) compared to 24-h Holter (19.0%, P < 0.001). Up to 87.2% of arrhythmias recorded with 14-day ECG patches were not associated with symptoms. The 14-day ECG patch was associated with higher detection rates compared to the 24-h Holter in patients with SVT (52.5% versus 15.8%, P < 0.001), irregular SVT without P wave (12.7% versus 4.4%, P = 0.002), AF/AFL (9.5% versus 3.8%, P = 0.042), and critical arrhythmias (pause ≥3 s, AVB, VT, polymorphic VT) (16.5% versus 2.5%, P < 0.001). The 14-day ECG patch detected more than 2 types of arrhythmias in 5.1% of patients. No serious adverse events in patients wearing the 14-day ECG patch were reported. ConclusionsThe 14-day ECG patch outperformed 24-h Holter to detect overall, asymptomatic, critical and multiple arrhythmias. It is safe and has the potential to identify individuals with hidden arrhythmias, especially those with critical arrhythmias.

Abstract 17461: Efficacy of Long-Term Monitoring on Detecting Critical Cardiac Arrhythmias

Introduction: The ambulatory continuous ECG monitors can provide a comprehensive cardiac assessment in outpatient settings. Extended cardiac monitoring is often needed by physicians to assess the efficacy of treatment, evaluate symptoms, and to stratify patients at risk. In this study, we compare the impact of outpatient cardiac monitoring between 1-14 days and 15-30 days. Method: A retrospective analysis was done on ECG data collected from 2,679 patients using Zywie ECG monitors (Zywie, Inc., Georgia). These patients were monitored for 14-30 days. We evaluated three arrhythmias in this study: i) Atrial fibrillation (AF) of duration &gt;15s ii) Ventricular tachycardia (VT) consisting of more than 3 heartbeats iii) Pause of duration &gt;3s. We analyzed the first occurrence of arrhythmia episodes in every patient during their monitoring period. We identified at least one episode of AF in 486 patients, VT in 106 patients, and pause in 78 patients. Results: The incidence of the first episode of AF, VT, and pause was observed after 14 days of monitoring in 15.8%, 28.3%, and 23.1% patients, respectively (Figure 1). Furthermore, among the VT episodes, 85.3% episodes had a duration between 1-10s and 14.7% with a duration &gt;10s. Similarly, 76% of identified pauses had a duration between 3-4s, 12% between 4-5s, and 12% with a duration &gt;5s. Conclusion: The results demonstrate the incremental diagnostic yield of critical arrhythmic events when the monitoring is extended beyond 14 days. This study suggests that long-term outpatient monitoring can provide better diagnosis, especially for patients at a higher risk of developing critical arrhythmias.

Real Time Non-Invasive Hemodynamic Assessment of Ventricular Tachycardia

Hemodynamically unstable ventricular tachycardia (VT) is a critical cardiac arrhythmia associated with hemodynamic compromise that requires immediate cardioversion to prevent sudden cardiac death. Since unnecessary cardioverter defibrillators shocks damage the heart and increase the risk of mortality, the discrimination between unstable (i.e. requiring cardioversion) and stable (i.e. not requiring cardioversion) VT is of paramount importance. The aim of this study was to propose and assess non-invasive identification of hemodynamically unstable VT using photoplethysmography (PPG). Seventy-five (n = 75) episodes of VT were recorded in 14 patients undergoing invasive electrophysiological studies for VT catheter ablation. Invasive continuous arterial blood pressure (ABP), PPG and electrocardiogram (ECG) were simultaneously recorded. VTs were classified as unstable if during the first 10 seconds from onset, the mean ABP ( $\overline {P_{VT}}\mathrm { ) was $\overline {P_{VT}}\mathrm { mmHg or if $\text{P}_{\mathrm {VT}}$ dropped more than 30% with respect to a 10 seconds baseline (i.e. ratio $\text{R}_{\mathrm {ABP}} ). Five PPG morphological features were derived and compared to the heart rate from the ECG. PPG markers detected hemodynamically unstable VT with accuracy as high as 86% and were more accurate than the heart rate. The mean absolute slope was the best PPG parameter for classification of $\overline {P_{VT}}\mathrm { mmHg (AUC = 0.85, Sensitivity = 72%, Specificity = 86%) and $\text{R}_{\mathrm {ABP}} (AUC = 0.90, Sensitivity = 83%, Specificity = 89%) and it was automatically selected in the best two-variables logistic regression, for which AUC = 0.94. In conclusion, PPG analysis can accurately identify haemodynamically unstable VTs and has potential to enable optimization of VT therapy and reduce unnecessary and harmful cardioversion shocks.

Performance of Different Atrial Conduction Velocity Estimation Algorithms Improves with Knowledge about the Depolarization Pattern

Abstract Quantifying the atrial conduction velocity (CV) reveals important information for targeting critical arrhythmia sites that initiate and sustain abnormal electrical pathways, e.g. during atrial flutter. The knowledge about the local CV distribution on the atrial surface thus enhances clinical catheter ablation procedures by localizing pathological propagation paths to be eliminated during the intervention. Several algorithms have been proposed for estimating the CV. All of them are solely based on the local activation times calculated from electroanatomical mapping data. They deliver false values for the CV if applied to regions near scars or wave collisions. We propose an extension to all approaches by including a distinct preprocessing step. Thereby, we first identify scars and wave front collisions and provide this information for the CV estimation algorithm. In addition, we provide reliable CV values even in the presence of noise. We compared the performance of the Triangulation, the Polynomial Fit and the Radial Basis Functions approach with and without the inclusion of the aforementioned preprocessing step. The evaluation was based on different activation patterns simulated on a 2D synthetic triangular mesh with different levels of noise added. The results of this study demonstrate that the accuracy of the estimated CV does improve when knowledge about the depolarization pattern is included. Over all investigated test cases, the reduction of the mean velocity error quantified to at least 25 mm/s for the Radial Basis Functions, 14 mm/s for the Polynomial Fit and 14 mm/s for the Triangulation approach compared to their respective implementations without the preprocessing step. Given the present results, this novel approach can contribute to a more accurate and reliable CV estimation in a clinical setting and thus improve the success of radio-frequency ablation to treat cardiac arrhythmias.

Cardiac Arrhythmia Simulations for Comparing Remote Telemetry Monitoring Systems

To increase the potential for timely detection of cardiac events, hospitalized patients who are at risk for critical arrhythmias are put on telemetry to continuously monitor their heart rhythm. However, telemetry monitoring systems vary widely between hospitals, there are few guidelines for decisions regarding optimal practices, and few studies have compared the efficiency of different monitoring systems. Our goal was to determine the impact of different monitoring systems on the time to detect and respond to critical cardiac events. To this end, we compared the process of communicating a critical alarm to the patient’s nurse in 2 hospitals with different monitoring systems, to determine the most efficient system. We conducted in situ unannounced simulations of cardiac arrest in the 2 hospitals to measure the response times of monitor watchers and patient care unit staff. As expected, we found response times to be shorter in the hospital that had a more direct method for monitor watchers to contact patients’ nurses. In addition to the method for communicating arrhythmias, there are many other differences between the monitoring systems in the 2 hospitals that could also have affected response times. We are using discrete event simulation to develop computer simulation models of the hospitals that will allow us to take multiple factors into account when comparing them.

Epidemiology of patient monitoring alarms in the neonatal intensive care unit

ObjectiveTo characterize the rate of monitoring alarms by alarm priority, signal type and developmental age in a Level-IIIB Neonatal Intensive Care Unit (NICU) population.Study DesignRetrospective analysis of 2 294 687 alarm messages from Philips monitors in a convenience sample of 917 NICU patients, covering 12 001 patient-days. We stratified alarm rates by alarm priority, signal type, postmenstrual age (PMA), and birth weight (BW) and reviewed and adjudicated over 21 000 critical alarms.ResultsOf all alarms, 3.6% were critical alarms, 55.0% were advisory alarms, and 41.4% were device alerts. Over 60% of alarms related to oxygenation monitoring. The average alarm rate (±SEM) was 177.1±4.9 [median: 135.9; IQR: 89.2–213.3] alarms/patient-day; the medians varied significantly with PMA and BW (p<0.001) in U-shaped patterns, with higher rates at lower and higher PMA and BW. Based on waveform reviews, over 99% of critical arrhythmia alarms were deemed technically false.ConclusionsThe alarm burden in this NICU population is very significant; the average alarm rate significantly underrepresents alarm rates at low and high PMA and BW. Virtually all critical arrhythmia alarms were artifactual.

Contemporary Tools and Techniques for Substrate Ablation of Ventricular Tachycardia in Structural Heart Disease.

As we have witnessed in other arenas of catheter-based therapeutics, ventricular tachycardia (VT) ablation has become increasingly anatomical in its execution. Multi-modality imaging provides anatomical detail in substrate characterization, which is often complex in nonischemic cardiomyopathy patients. Patients with intramural, intraseptal, and epicardial substrates provide challenges in delivering effective ablation to the critical arrhythmia substrate due to the depth of origin or the presence of adjacent critical structures. Novel ablation techniques such as simultaneous unipolar or bipolar ablation can be useful to achieve greater lesion depth, though at the expense of increasing collateral damage. Disruptive technologies like stereotactic radioablation may provide a tailored approach to these complex patients while minimizing procedural risk. Substrate ablation is a cornerstone of the contemporary VT ablation procedure, and recent data suggest that it is as effective and more efficient that conventional activation guided ablation. A number of specific targets and techniques for substrate ablation have been described, and all have shown a fairly high success in achieving their acute procedural endpoint. Substrate ablation also provides a novel and reproducible procedural endpoint, which may add predictive value for VT recurrence beyond conventional programmed stimulation. Extrapolation of outcome data to nonischemic phenotypes requires caution given both the variability in substrate nonischemic distribution and the underrepresentation of these patients in previous trials.

Intraoperative management of liver transplant recipients having severe renal dysfunction: results of 42 cases.

PurposeWhereas continuous renal replacement therapy (CRRT) has been utilized during liver transplantation (LT), there was a lack of evidence to support this practice. We investigated the adverse events at the perioperative periods in recipients of LT who received preoperative CRRT without intraoperative CRRT.MethodsWe retrospectively reviewed medical records of adult patients (age ≥ 18 years) who received LT between December 2009 and May 2015. Perioperative data were collected from the recipients, who received preoperative CRRT until immediately before LT, because of refractory renal dysfunction.ResultsOf 706 recipients, 42 recipients received preoperative CRRT. The mean (standard deviation) Model for end-stage liver disease score were 49.6 (13.4). Twenty-six point two percent (26.2%) of recipients experienced the serum potassium > 4.5 mEq/L before reperfusion and treated with regular insulin. Thirty-eight point one percent (38.1%) of recipients were managed with sodium bicarbonate because of acidosis (base excess < −10 mEq/L throughout LT). All patients finished their operations without medically uncontrolled complications such as severe hyperkalemia (serum potassium > 5.5 mEq/L), refractory acidosis, or critical arrhythmias. Mortality was 19% at 30 day and 33.3% at 1 year.ConclusionAlthough intraoperative CRRT was not used in recipients with severe preoperative renal dysfunction, LT was safely performed. Our experience raises a question about the need for intraoperative CRRT.

Critical arrhythmia in postoperative cardiac children: Recognition and management.

Arrhythmias after pediatric cardiac surgery are common and can be life-threatening. They occur intraoperatively or may appear shortly after surgery during postoperative care. They require early management and specific intervention. In this review, we describe important critical arrhythmias that are encountered during postoperative management of children undergoing cardiac surgery. We review the diagnosis, management, and explain the role of epicardial electrocardiogram in diagnosing certain types of postoperative rhythm abnormalities seen during early period after pediatric cardiac surgery.

Reducing false asystole alarms in intensive care.

High rates of false monitoring alarms in intensive care can desensitize staff and therefore pose a significant risk to patient safety. Like other critical arrhythmia alarms, asystole alarms require immediate attention by the care providers as a true asystole event can be acutely life threatening. Here, it is illustrated that most false asystole alarms can be attributed to poor signal quality, and we propose and evaluate an algorithm to identify data windows of poor signal quality and thereby help suppress false asystole alarms. The algorithm combines intuitive signal-quality features (degree of signal saturation and baseline wander) and information from other physiological signals that might be available. Algorithm training and testing was performed on the MIMIC II and 2015 PhysioNet/Computing in Cardiology Challenge databases, respectively. The algorithm achieved an alarm specificity of 81.0% and sensitivity of 95.4%, missing only one out of 22 true asystole alarms. On a separate neonatal data set, the algorithm was able to reject 89.7% (890 out of 992) of false asystole alarms while keeping all 22 true events. The results show that the false asystole alarm rate can be significantly reduced through basic signal quality evaluation.

Prediction of New-Onset and Recurrent Atrial Fibrillation by Complete Blood Count Tests: A Comprehensive Systematic Review with Meta-Analysis

BackgroundAtrial fibrillation (AF) is one of the most critical and frequent arrhythmias precipitating morbidities and mortalities. The complete blood count (CBC) test is an important blood test in clinical practice and is routinely used in the workup of cardiovascular diseases. This systematic review with meta-analysis aimed to determine the strength of evidence for evaluating the association of hematological parameters in the CBC test with new-onset and recurrent AF.Material/MethodsWe conducted a meta-analysis of observational studies evaluating hematologic parameters in patients with new-onset AF and recurrent AF. A comprehensive subgroup analysis was performed to explore potential sources of heterogeneity.ResultsThe literature search of all major databases retrieved 2150 studies. After screening, 70 studies were analyzed in the meta-analysis on new-onset AF and 23 studies on recurrent AF. Pooled analysis on new-onset AF showed platelet count (PC) (weighted mean difference (WMD)=WMD of −26.39×109/L and p<0.001), mean platelet volume (MPV) (WMD=0.42 FL and p<0.001), white blood cell (WBC) (WMD=−0.005×109/L and p=0.83), neutrophil to lymphocyte ratio (NLR) (WMD=0.89 and p<0.001), and red blood cell distribution width (RDW) (WMD=0.61% and p<0.001) as associated factors. Pooled analysis on recurrent AF revealed PC (WMD=−2.71×109/L and p=0.59), WBC (WMD=0.20×109/L (95% CI: 0.08 to 0.32; p=0.002), NLR (WMD=0.37 and p<0.001), and RDW (WMD=0.28% and p<0.001).ConclusionsHematological parameters have significant ability to predict occurrence and recurrence of AF. Therefore, emphasizing the potential predictive role of hematological parameters for new-onset and recurrent AF, we recommend adding the CBC test to the diagnostic modalities of AF in clinical practice.