High Arrhythmic Risk Research Articles

RISK PREDICTION FOR ARRHYTHMIA IN PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

The aim: To evaluate P-wave dispersion (PwD), as an independent predictor of atrial fibrillation, corrected QT interval dispersion (cQTD), the noninvasive marker of ventricular arrhythmia and sudden cardiac death, investigate the atrial electromechanical delay in patients with COPD and assess their relation with the severity of the disease. Materials and methods: We prospectively enrolled consecutive patients with newly diagnosed COPD (n = 53, age 41.2 ± 6.8 years), compared with an age-matched healthy control group (n = 51, age 40.9 ± 6.5 years). A standard 12-lead electrocardiogram of each patient was analyzed for PwD and сQTD. Atrial electromechanical delay was analyzed by echocardiographic tissue Doppler imaging. The difference between PAs-PAl, PAs-PAt, and PAl-PAt were defined as left intra-atrial, right intra-atrial, and interatrial electromechanical delays (EMD), respectively. Results: PwD was higher in COPD patients than in control subjects (39.47 ± 3.12 ms vs. 30.29 ± 3.17 ms, p < 0.05). In comparison between control group and COPD subgroups (mild, moderate and severe), there was a statistically significant difference among these free groups in terms of PwD. Subgroup analyses showed that this difference was mainly due to patients with severe COPD. Regarding cQTD, there was a statistically significant increase in COPD patients 57.92 ± 3.43 ms vs 41.03 ± 5.21 ms, p < 0.05 respectively. PAs, PAl and PAt durations, right intra-atrial and interatrial EMD were also significantly longer in COPD patients (p < 0.05). Furthermore, there were significant negative correlations between FEV1 and PwD (r = – 0.46, p < 0.05), right intra-atrial (r = – 0.39 ms, p < 0.05), interatrial EMD ( r = – 0.35 ms, p < 0.05) and cQTD (r = – 0.32, p < 0.05). Conclusions: Atrial conduction time, such as inter- and intra-atrial EMD intervals, PwD and cQTD were longer than in healthy controls and correlated with the severity of COPD. These parameters offer a non-invasive and cost-effective assessment method for detecting patients at high risk of arrhythmia. Nevertheless, further prospective investigations on this issue are required.

Impact of Obstructive Sleep Apnoea on Rate of Dysrrhythmia and Outcome in Stroke Admissions on the Medical Service of Jos University Teaching Hospital

Obstructive sleep apnoea (OSA) is said to be associated with stroke and can be modulated to advantage. Given its impact on atrial fibrillation (AF), a predictor of severity and poor stroke outcome, we decided to study the relationship of OSA with arrhythmias and outcome in stroke patients admitted on our service. Stroke patients admitted and confirmed by neuro-imaging were examined physically, underwent 24 hour Holter monitoring and assessed for severity, dependency and survival status by 4 weeks after admission. They had arterial blood saturation checked between 10 pm and 2 am. Saturation < 90% defined OSAS and it was correlated with presence of arrhythmias, severity of stroke and outcome measures. Ninety four patients (52 M, 42 F) were enrolled. Ten, 6 M 4 F had OSA with a mean age of 56.00±16.80 years. AF was more associated with OSA to a statistically significant extent (chi-square=7.453, p=0.006). When it comes to mortality or whether patient was still on admission or had been discharged by 4 weeks, presence of OSA made an obvious difference. (chi-square=16.202. p=0.001). Those with OSA were more dependent 4 weeks after admission and had more severe stroke, but the difference missed statistical significance. In conclusion, OSA in stroke patients is fraught with a high risk of arrhythmias in which presence strokes are more severe with poorer outcomes. Appropriate management of OSA in patients at risk of stroke or after the ictus is bound to mitigate the burden and consequences of stroke.

R-Wave Singularity: A New Morphological Approach to the Analysis of Cardiac Electrical Dyssynchrony.

R-wave singularity (RWS) measures the intermittence or discontinuousness of R waves. It has been broadly used in QRS (QRS complex of electrocardiogram) detection, electrocardiogram (ECG) beats classification, etc. In this article, we novelly developed RWS to the analysis of QRS morphology as the measurement of ventricular dyssynchrony and tested the hypothesis that RWS could enhance the discrimination between control and acute myocardial infarction (AMI) patients. Holter ECG recordings were obtained from the Telemetric and Holter ECG Warehouse database, among which database Normal was extracted as normal controls (n = 202) and database AMI (n = 93) as typical subjects of autonomic nervous system dysfunction and cardiac electrical dyssynchrony with high risk for cardiac arrhythmias and sudden cardiac death. Experimental results demonstrate that RWS measured by Lipschitz exponent calculated from 5-min Holter recordings was significantly less negative in early AMI and late AMI than that in Normal subjects for overall, elderly, and elderly male groups, which suggested the heterogeneous depolarization of the ventricular myocardium during AMI. Receiver operating characteristic curve analyses show that combined with heart rate variability parameters, Lipschitz exponent provides higher accuracy in distinguishing between the patients with AMI and healthy control subjects for overall, elderly, elderly male, and elderly female groups. In summary, our study demonstrates the significance of using RWS to probe the cardiac electrical dyssynchrony for AMI. Lipschitz exponent may be valuable and complementary for existing cardiac resynchronization therapy and autonomic nervous system assessment.

Electrophysiological and anatomical factors determine arrhythmic risk in acute myocardial ischaemia and its modulation by sodium current availability.

Acute myocardial ischaemia caused by coronary artery disease is one of the main causes of sudden cardiac death. Even though sodium current blockers are used as anti-arrhythmic drugs, decreased sodium current availability, also caused by mutations, has been shown to increase arrhythmic risk in ischaemic patients. The mechanisms are still unclear. Our goal is to exploit perfect control and data transparency of over 300 high-performance computing simulations to investigate arrhythmia mechanisms in acute myocardial ischaemia with variable sodium current availability. The human anatomically based torso-biventricular electrophysiological model used includes representation of realistic ventricular anatomy and fibre architecture, as well as ionic to electrocardiographic properties. Simulations show that reduced sodium current availability increased arrhythmic risk in acute regional ischaemia due to both electrophysiological (increased dispersion of refractoriness across the ischaemic border zone) and anatomical factors (conduction block from the thin right ventricle to thick left ventricle). The asymmetric ventricular anatomy caused high arrhythmic risk specifically for ectopic stimuli originating from the right ventricle and ventricular base. Increased sodium current availability was ineffective in reducing arrhythmic risk for septo-basal ectopic excitation. Human-based multiscale modelling and simulations reveal key electrophysiological and anatomical factors determining arrhythmic risk in acute ischaemia with variable sodium current availability.

Abstract 16730: Computerized Prediction of Avoidable Serum Potassium Testing in Critically Ill Cardiac Patients

Introduction: Electrolytes are frequently monitored among critically ill patients, especially among cardiac patients due to higher risk of arrhythmias. However, a percentage of these blood draws may potentially be saved. To date, no studies have investigated strategies to safely reduce the density of electrolyte monitoring in critically ill patients. Hypothesis: We hypothesized that machine learning models can identify potentially avoidable blood draws for serum potassium (K) among pediatric patients following cardiac surgery. Methods: We retrospectively reviewed data of all patients admitted to the CICU at Boston Children’s Hospital during 2010-2018, having a length of stay ≥4 days and ≥2 recorded serum K measurements. We collected variables related to K homeostasis, including serum chemistry, hourly K intake, diuretics, and urine output. Using established machine learning techniques (Random Forest classifiers and hyperparameters) we created models predicting whether a patient’s K would be normal or abnormal based on the most recent K level, medications administered, urine output, and markers of renal function. We developed multiple models based on different age categories and temporal proximity of the most recent K measurement. We assessed the predictive performance of the models using an independent test set. Results: Of the 7,269 admissions (6,196 patients) included, 95,674 serum K was measured on average of 1 (IQR 0-1) time per day. 96% of patients received at least one dose of IV diuretic and 83% received a form of K supplementation. Our models predicted a normal K value with a median positive predictive value of 0.90. A median percentage of 2.1% measurements (mean 2.5%, IQR 1.3%-3.7%) were incorrectly predicted as normal when they were abnormal. A median percentage of 0.0% (IQR 0.0%-0.4%) were incorrectly predicted as normal while being critically low or high. A median of 27.2% (IQR 7.8%-32.4%) of samples were correctly predicted to be normal and could have been potentially avoided. Conclusions: Machine-learning methods can be used to accurately predict avoidable blood tests for serum K in critically ill pediatric patients. A median of 27.2% of samples could have been saved, with decreased costs and risk of infection or anemia.

Evidence-based Management of Arrhythmogenic Right Ventricular Cardiomyopathy in Pregnancy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder resulting in fibrofatty replacement of the myocardium. Genetic mutations in genes encoding for desmosome proteins result in a ventricular myocardium prone to arrhythmias and heart failure. Although ARVC is known for a few decades, most of the outcomes in pregnancy are reported recently. Pregnancy leads to significant physiological changes with excess mechanical stress on the myocardium. All the retrospective studies suggest that pregnancy is well tolerated in these patients despite the high risk of arrhythmias and heart failure. Our review focuses on the most up-to-date evidence on the management of ARVC patients during the antepartum and postpartum period.

Worse Prognosis in Brugada Syndrome Patients With Arrhythmogenic Cardiomyopathy Features.

This study aimed to assess the presence of echocardiographic and electrocardiographic similarities in patients with Brugada syndrome (BrS) and arrhythmogenic cardiomyopathy (AC) and the prevalence and prognostic value of AC structural/electrical features in patients with BrS. BrS and AC are genetic cardiac diseases with high risk for sudden cardiac death. Although BrS and AC display different features, previous reports suggest a phenotypic overlap. We acquired clinical data, electrocardiogram, and transthoracic echocardiography in patients with BrS and AC. We assessed the presence of AC diagnostic criteria according to the 2010 AC task force criteria for right ventricular outflow tract (RVOT), fractional area change, depolarization, and repolarization in the patients with BrS. We compared arrhythmic outcome in BrS patients with and without AC structural/electrical criteria. A total of 116 BrS and 141 AC patients were included. AC electrical features were present in 28 (24%) BrS patients and structural features in 97 (84%) BrS patients. BrS patients with an RVOT or depolarization AC criterion showed a trend towards worse severe arrhythmia-free survival compared to BrS patients without (p=0.05). The criterion for RVOT dilation showed high sensitivity and improved detection of arrhythmic BrS patients when added to type 1 electrocardiogram pattern and syncope (area under the curve 0.73 [95% confidence interval: 0.59 to 0.87] vs. area under the curve 0.79 [95% confidence interval: 0.69 to 0.90]); p=0.009). In this large cohort comparison, Brugada syndrome (BrS) and arrhythmogenic cardiomyopathy patients had phenotypic overlap. The presence of arrhythmogenic cardiomyopathy diagnostic criteria in BrS patients was associated with a trend towards higher arrhythmic risk. The right ventricular outflow tract dilation criterion improved detection of arrhythmic BrS patients.

QTc prolongation during antiviral therapy in two COVID‐19 patients

What is known and objectiveAcquired long QT syndrome secondary to drug‐induced QT prolongation and torsades de pointes has been reported for antiviral drugs. However, no studies have reported an association between corrected QT (QTc) prolongation and antiviral therapy in patients with novel coronavirus disease (COVID‐19).Case descriptionWe present two cases from our institution in which patients with COVID‐19 experienced QTc prolongation during treatment with antiviral therapy. Lopinavir/ritonavir, together with gender and drug‐drug interactions, may have contributed to the induction of QTc prolongation in those patients.What is new and conclusionCo‐administration of QT‐prolonging medications and drugs interfering with the metabolism of those medications must be considered in patients with COVID‐19. Careful analysis of electrocardiograms for QTc duration should be performed at baseline and during antiviral therapy to identify individuals at high risk of arrhythmias.

P1113Patchy localisation of late gadolinium enhancement associated with ventricular arrhythmia in dilated cardiomyopathy

Abstract Funding Acknowledgements None Introduction Myocardial fibrosis detected using late gadolinium enhancement(LGE) on cardiac magnetic resonance(CMR) imaging holds prognostic value in dilated cardiomyopathy(DCM). Recent reports have demonstrated the localisation of LGE to be promising predictors of ventricular arrhythmic (VA).Aim: To determine the localisation of LGE associated with high risk of VA in DCM patients. Methods: Retrospective review of consecutive DCM patients(n = 85) implanted with an implantable cardioverter defibrillator(ICD) at a single tertiary centre between 2011-2018. All patients with insufficient follow-up data, cardiac channelopathies, primary valvular pathology and congenital heart disease were excluded from analysis(n = 11). Details of VA occurrence were obtained from medical and pacing notes. VA was defined as VA causing haemodynamic compromise or appropriate device therapy (anti-tachycardia pacing/shock). Localisation of LGE was defined as midwall, patchy, subepicardial or transmural. Left ventricular ejection fraction(LVEF) &amp;lt;35% was defined as severely impaired function. Results:74 DCM patients implanted with an ICD were identified for analysis; LGE was observed in 18(60%) VA and 29(66%) non-VA patients(p = 0.6). There was no observed difference in mean age for patients with and without LGE (68 ± 10 vs. 65 ± 10 years,p = 0.07). A significant difference was seen between localisation and VA (p = 0.04), with patchy LGE demonstrating a higher arrhythmic risk(p = 0.005). There was no association between LVEF and LGE(p = 0.2) however, a significant difference was seen in LVEF and arrhythmic risk, with a more severely impaired LV function seen in patients without VA(p = 0.01). Conclusion:This study has demonstrated a patchy LGE localisation to be strongly associated with ventricular arrhythmia in DCM. Whilst this is a valuable tool in risk stratification, a prospective study with a larger population is required to confirm the validity of this finding. Moreover, an additional method will need to be considered to identify high risk patients without LGE. Ventricular Arrhythmia (n = 30) No Ventricular Arrhythmia (n = 44) P Value Male(%) 20(67%) 24(55%) p = 0.29 Age(Mean ± SD) 65 ± 12 65 ± 10 p = 0.36 LGE Midwall 10(56%) 24(83%) p = 0.04 Subepicardial 1(5.5%) 2(7%) p = 0.85 Transmural 1(5.5%) 2(7%) p = 0.85 Patchy 6(33%) 1(3%) p = 0.005 LVEF &amp;lt;35% 23(77%) 42(95%) p = 0.01

Use of Chloroquine and Hydroxychloroquine in COVID-19 and Cardiovascular Implications: Understanding Safety Discrepancies to Improve Interpretation and Design of Clinical Trials.

Author(s): Oren, Ohad; Yang, Eric H; Gluckman, Ty J; Michos, Erin D; Blumenthal, Roger S; Gersh, Bernard J

Analysis of QT Dispersion, Corrected QT Dispersion, and P-Wave Dispersion Values in Alcohol Use Disorder Patients With Excessive Alcohol Use.

To identify the changes in QT dispersion (QTd), corrected QTd (QTcd), and P-wave dispersion (Pd) values with long-term alcohol abuse that could lead to severe ventricular arrhythmia, atrial fibrillation, and sudden death in alcohol use disorder (AUD) patients with excessive alcohol use. This cross-sectional study included 48 individuals diagnosed with AUD based on DSM-5 criteria. Patients with a history of psychiatric diseases were not included. The control group comprised 48 individuals with no psychiatric diagnosis who did not abuse alcohol or other substances. Participants with body mass index > 24.9 kg/m² were excluded. Twelve-derivation electrocardiograms (ECG) were obtained from all participants. The mean ± SD age was 44.35 ± 10.24 years in the AUD group and 40.90 ± 13.45 years in the control group. There was no significant difference between the groups based on age (P = .108). There was a significant difference between the groups based on smoking status (P = .000). The mean ± SD period of alcohol use was 20.71 ± 12.04 years, and the alcohol intake was 5.88 ± 1.65 units/d. The AUD group demonstrated elevations in all ECG measures (QTd: 46.56 vs 26.67 ms, QTcd: 54.25 vs 30.88 ms, Pd: 44.69 vs 28.54 ms, all P = .000). AUD patients with excessive alcohol use had a higher risk of arrhythmia and sudden death compared to the control group. Consideration of ECG and referral to cardiologic examinations would contribute to the follow-up and health of patients with AUD.

P1427 Mechanical dispersion assessed with echocardiography versus scar characterization with cardiac magnetic resonance to predict malignant arrhythmia in cardiac resynchronization therapy patients

Abstract Background Recent data have shown that scar characterization with late gadolinium enhancement magnetic resonance (LGE-CMR) is useful to predict malignant arrhythmic events in a cardiac resynchronization therapy (CRT) population. On the other hand, echocardiography 2D strain parameters (such as mechanical dispersion – MD) have been recently suggested as a predictor of ventricular arrhythmia (VA). Purpose To compare the usefulness of strain echocardiography and MR scar parameters to predict VA and sudden cardiac death (SCD) in CRT patients (pa). Methods 110 pa undergoing CRT implant were included. A 2D strain echo and a 3D LGE-CMR were performed before the implant. In the echocardiographic exam, left ventricle ejection fraction (LVEF), global longitudinal strain (GLS), mechanical dispersion (MD) and delta contraction time were quantified. Regarding LGE-CMR, scar mass, border zone (BZ) mass and the presence of BZ channels were assessed with specific software. The primary endpoint was the presence of SCD or appropriate implantable cardioverter-defibrillator therapy at long-term follow-up (FU). Results The primary outcome occurred in 23 pa (20.9%) during a mean FU of 53.5 ± 10.4 months. In these pa, MD was significantly increased (130.3 ± 55.5ms vs. 102.0 ± 45.1ms, p &amp;lt; 0.05) whereas LVEF, GLS and delta contraction time were not significantly different. All LGE-CMR parameters were significantly increased in PA with events. At multivariate analysis, both MD and LGE-CMR parameters were independent predictors of malignant arrhythmia (table). The MD cut-off value for prediction of VA was 80.88 ms, with 91.3% sensitivity and 36.8% specificity. The figure shows the Kaplan-Meier curves. Regarding LGE-CMR parameters, the cut-off value, sensitivity, and specificity were 13.8g/82.6%/81.6% for scar mass, 5.54g/85.7%/81.8% for BZ mass, and 90.9%/82.1% for presence of BZ channels. Conclusions MD and LGE-CMR scar parameters are independent predictors of VA and SCD in CRT. Due to its high sensitivity, MD could be used to identify pa at high arrhythmic risk that could benefit from a more complex and specific LGE-CMR study. Multivariate analysis Model 1 Model 2 Model 3 HR (95% CI) p HR (95% CI) p HR (95% CI) p Basal LVEF 1.01 (0.94-1.09) 0.731 1 (0.93-1.07) 0.974 1.04 (0.97-1.11) 0.273 MD (ms) 1.01 (1.00-1.02) 0.043 1.01 (1.00-1.02) 0.017 1.01 (1.00-1.02) 0.003 BZ mass (g) 1.08 (1.05-1.11) &amp;lt;0.001 Presence of BZ channels 18.39 (4.26-79.51) &amp;lt;0.001 Scar mass (g) 1.06 (1.04-1.08) &amp;lt;0.001 LVEF: left ventricle ejection fraction; MD:mechanical dispersion; BZ:border zone Abstract P1427 Figure. Kaplan-Meier curves

P186 In search of lost time

Abstract Arrhythmogenic right ventricular dysplasia (ARVD) is one of the most difficult to diagnose and manage of the cardiomyopathies. Physical exercise can be a contributing factor and may accelerate the progression of the disease. We present the case of a 49-year-old, a former professional football player, with a history of cardiac arrest in 2011 by ventricular tachycardia (VT) (normal coronary arteries). Between 2011 and 2019 the patient didn"t present for reevaluation and resumed endurance sports activity in spite of doctor recommendation. In 2019 he was directed to our clinic for a syncope followed by constrictive anterior chest pain and palpitations, the clinical expression of a VT with LBBB morphology and inferior axis, most likely originated in the RVOT, for which cardioversion was required. Upon admission, the patient was hemodynamically and respiratory stable, at sinus rhythm 60/min with left anterior hemiblock and negative T waves in V1-V2. Biologically, myocardial and hepatic cytolysis enzymes were within normal limits, with mild hypokalemia. Echocardiography showed significant dilatation of RV and RVOT with RV dysfunction (TAPSE 16 mm, FAC 20%, s" 8.6 cm/s). LV was nondilated, with normal systolic function and kinetic, but with trabeculation of the apex. To confirm the diagnosis of ARVD, cardiac MRI was performed and confirmed fat infiltration in the RV free wall with biventricular involvement. Given the high arrhythmic risk (two resuscitated VT episodes, syncope), a two-chamber ICD was implanted, without immediate post-procedural complications. In the second postprocedural day, the patient suddenly installed important epigastric pain with thoracic irradiation. The ECG showed sensing and pacing malfunction and radioscopy showed evidence of ventricular probe displacement. The echocardiography confirmed the myocardial perforation. Emergency surgery by median thoracotomy was performed, with successful extraction of the electrode and myocardial suture. Postoperative progression was favorable under treatment with beta-blocker and amiodarone. A subcutaneous ICD will be implanted as soon as available. In conclusion, this case is a very particular one. First of all, we’ve documented two distinct phases in the evolution of the ARVD (electrical phase – 2011 and structural phase - 2019). Moreover, by resuming endurance sports activity and in concordance with the literature data, we can only assume that the progression of the disease was accelerated and the arrhythmic risk was greater. Complications related to probe stability are common in this population, but myocardial perforation is a very rare and dangerous one. The therapeutic management of patients with ARVD has evolved over the years and continues to be an important challenge. To further improve risk stratification and treatment of patients, more information is needed on the natural history, long-term prognosis, and risk assessment. Abstract P186 Figure. Echocardiografic and MRI aspect

P275 Feasibility and accuracy of the automated quantification of two- and three-dimensional left ventricular ejection fraction and its role in the arrhythmic risk stratification of organic heart disease

Abstract BACKGROUND New automated approaches for left heart chamber quantification based on adaptive analytics algorithms have been introduced for both two- (2DE) and three-dimensional (3DE) echocardiography. These algorithms measure a left ventricular ejection fraction (LVEF) and reduce the intra- and inter-observer variability associated with the conventional manual tracing of LV endocardial borders. However, the clinical utility of these algorithms in the sudden cardiac death (SCD) risk stratification of patients with organic heart disease remains to be clarified. PURPOSE We sought to test the feasibility and the accuracy of two automated algorithms that measure 2DE and 3DE LVEF in patients with impaired LV systolic function and to define the cut-off values for fully automated 2DE and 3DE LVEF that could predict major arrhythmic events (MAE). We wanted also to assess the feasibility of replacing manual 2DE and semi-automated (SA) 3DE LVEF with fully-automated (FA) 2DE and 3DE LVEF respectively, in the stratification of high arrhythmic risk patients. METHODS We prospectively enrolled 240 patients (63 ± 13 years, 81% men) with both ischemic and non-ischemic cardiomyopathy with 2DE LVEF &amp;lt; 50%, no previous MAE or coronary artery revascularization &amp;lt; 90 days, after at least 3 months of optimal medical therapy for heart failure. MAE were defined as SCD, resuscitated cardiac arrest (CA), ventricular fibrillation, sustained ventricular tachycardia and appropriate ICD shocks. The risk detection cut-off values for 2DE and 3DE FA LVEF were computed using the maximally selected rank statistics method. In order to predict the risk of MAE we created four different risk models, including both clinical characteristics (age, NYHA class, aetiology of the LV dysfunction) and imaging-derived data (2DE manual LVEF, 2DE FA LVEF, 3DE SA LVEF and 3DE FA LVEF), analyzed by a ROC curve. RESULTS During a 27 ± 25months follow-up period, 31 patients (13%) presented MAE including SCD (n= 22; 9%), resuscitated CA (n = 3; 1%) and appropriate ICD shocks (n = 6; 2%). Both 2DE and 3DE FA LVEF showed high feasibility (92% and 95%, respectively), and good agreement with conventional LVEF (2DE mean difference 4 ± 7%, and 3DE mean difference 4 ± 7%). We identified two FA LVEF cut-offs for the MAE detection: 2DE &amp;lt;39% (p = 0.006) and 3DE &amp;lt;37% (p = 0.005). The model including the 2DE FA LVEF showed an area under the curve (AUC) larger than the one including conventional 2DE LVEF (0.83 vs 0.80). Conversely, the AUC obtained with FA 3DE LVEF model was slightly lower than the one obtained using SA 3DE LVEF model (0.80 vs 0.84). CONCLUSIONS Both 2DE and 3DE FA LVEF are feasible and accurate alternative to the conventional (manual) or SA endocardial border tracing. The use of specific FA 2DE LVEF cut-off values showed a comparable predictive power in the MAE risk stratification compared to the conventional one with the advantage of very low intra- and inter-observer variability.

Clinical significance of postoperative atrial arrhythmias in patients who underwent lung transplantation.

Background/AimsAtrial arrhythmia (AA) occasionally occurs after lung transplantation (LT); however, risk factors for AA and their impact on clinical outcomes are inconsistent. We aimed to investigate the incidence, predisposing factors, and clinical outcomes of AA after LT.MethodsWe retrospectively evaluated 153 consecutive patients who underwent LT between January 2010 and August 2016. An AA episode was defined as a documented atrial fibrillation (AF), atrial flutter, or atrial tachycardia on 12-lead electrocardiography or episodes lasting ≥ 30 seconds on telemetry monitoring.ResultsThe mean follow-up time was 22.0 ± 19.1 months. Postoperative AA occurred in 46 patients (30.1%) after LT. Patients with postoperative AA were older, had larger body surface area, and had an increased incidence of paroxysmal AF prior to transplantation, idiopathic pulmonary fibrosis, and postoperative tracheostomy than patients without AA. Preoperative right atrial pressure (RAP) (odds ratio [OR], 1.19; p = 0.005) and longer periods of mechanical ventilation (OR, 1.03; p = 0.008) were found to be independent risk factors for AA after surgery. Development of AA was a significant predictor of long-term overall mortality (hazard ratio, 2.75; p = 0.017).ConclusionsPatients with elevated preoperative RAP and long-term ventilator care had a higher risk of AA after LT. Further, AA after LT was associated with poor long-term survival.

High arrhythmic risk in antero-septal acute myocardial ischemia is explained by increased transmural reentry occurrence

Acute myocardial ischemia is a precursor of sudden arrhythmic death. Variability in its manifestation hampers understanding of arrhythmia mechanisms and challenges risk stratification. Our aim is to unravel the mechanisms underlying how size, transmural extent and location of ischemia determine arrhythmia vulnerability and ECG alterations. High performance computing simulations using a human torso/biventricular biophysically-detailed model were conducted to quantify the impact of varying ischemic region properties, including location (LAD/LCX occlusion), transmural/subendocardial ischemia, size, and normal/slow myocardial propagation. ECG biomarkers and vulnerability window for reentry were computed in over 400 simulations for 18 cases evaluated. Two distinct mechanisms explained larger vulnerability to reentry in transmural versus subendocardial ischemia. Macro-reentry around the ischemic region was the primary mechanism increasing arrhythmic risk in transmural versus subendocardial ischemia, for both LAD and LCX occlusion. Transmural micro-reentry at the ischemic border zone explained arrhythmic vulnerability in subendocardial ischemia, especially in LAD occlusion, as reentries were favoured by the ischemic region intersecting the septo-apical region. ST elevation reflected ischemic extent in transmural ischemia for LCX and LAD occlusion but not in subendocardial ischemia (associated with mild ST depression). The technology and results presented can inform safety and efficacy evaluation of anti-arrhythmic therapy in acute myocardial ischemia.

THE ROLE OF HEMOLYSIS IN THE EMERGENCE OF HEART RHYTHM DISORDERS AFTER CORONARY BYPASSING

The operation of coronary shunting in patients with coronary heart disease leads to the development of various complications in the postoperative period, the most frequent are heart rhythm disturbances.Purpose. To establish the connection of intraoperative hemolysis (IOH) with the development of cardiac rhythm disturbances in patients with coronary artery disease after coronary shunting in con-ditions of cardiopulmonary bypass (CB).Material and research methods. The assessment of the degree of IOH was made by the level of free hemoglobin [Hb] In the blood plasma at the beginning of the operation, immediately after the patient was connected to the CB device and 15 minutes before removal from the CB, using the HemoCue Plasma / Low Hb analyzer. According to the degree of IOH, patients (n = 123) are divided into 3 groups (gr.) in accordance with free [Hb]: gr.1 - ≤0,1 g/l; gr.2 - &gt; 0.1 g/l and &lt;0,5 g/l; gr.3 - ≥0,5g/l. Were used the following instrumental methods of investigation: electrocardiography, 24-hour ECG mon itoring. Was analyzed the frequency of heart rhythm disturbances in patients after coronary shunting with various levels of IOH in the perioperative (during the operation and during the first days after it) and in the early (up to 1 month) periods.Results. Arrhythmias were observed in 2.3% of patients of the 1st group, in 11.9% - the 2nd group, in 52.6% - the 3rd group. Associations were noted between [Hb]. In plasma at the end of cardio-pulmonary bypass and the frequency of arrhythmias (rs=0,70, p&lt;0.001). The share of life-threatening and hemodynamically significant arrhythmias in the study period in the group with a high degree of IOH accounted for about half of all arrhythmias that occur, which is significantly more than in the group without IOH and with low IOH, p &lt;0.001.Conclusion.The operation of coronary artery bypass surgery in conditions of artificial blood circu-lation leads to the development of arrhythmias in the postoperative period in 22% of patients with ischemic heart disease. A significant proportion of these are arrhythmias that pose a threat to the pa-tient’s life and arrhythmias, causing hemodynamic disturbances and hypoperfusion of vital organs. The largest number of patients with cardiac rhythm disturbances after coronary artery bypass graft-ing was observed in the group with the level of free hemoglobin in the blood plasma of 0.5 g/l or more (p &lt;0.001), which indicates the relationship between the occurrence of arrhythmias and the degree of intraoperative hemolysis. The high risk of arrhythmias in patients with coronary heart dis-ease after coronary artery bypass surgery is determined when the content of free hemoglobin is more than 0.85 g/l. One of the ways to assess the risk of heart rhythm disturbances should be to determine the level of free hemoglobin in the blood plasma of patients in the intraoperative period of coronary artery by-pass grafting, which is necessary for the timely prevention and correction of possible hemodynamic disorders.

Electrical properties of the myocardium in patients with arterial hypertension combined with subclinical hypothyroidism

Late atrial and ventricular potentials are non-invasive electrocardiographic criteria for presence of high arrhythmic readiness and risk of life-threatening arrhythmias. The electrical properties of the myocardium in patients with stage II arterial hypertension (AH) combined with subclinical hypothyroidism have not been studied previously.Aim. To study the changes of electrical properties of the atrial and ventricular myocardium in patients with AH combined with subclinical hypothyroidism.Materials and methods. The criteria for inclusion in the study were the presence of stage II AH without thyroid gland pathology and combined with subclinical hypothyroidism (SH) (for patients of the main group). Depending on the level of thyroid-stimulating hormone (TSH), the AH patients were divided into 2 groups – with normal (0.4–4.0 mU/ml) and moderately elevated level of TSH (4.0–15.6 mU/l, with normal levels of thyroid hormones).The group of patients with AH without SH included 92 patients (women – 81.52 % (75), men – 18.48 % (17)); the group of patients with AH with concomitant SH included 30 patients (women – 86.7% (26), men – 13.3 % (4)). All patients underwent 24-h BP monitoring and ECG (combined ECG and BP monitor “Kardiotechnica-04-AD-3”,St. Petersburg,Russia). A 40 Hz cutoff filter was used recording in the X, Y, Z orthogonal leads. Data were processed with the help of a program Statistica 6.0. Data were presented as the median and inter-quartile range of Me (25 %; 75 %).Results. In AH patients without concomitant subclinical hypothyroidism, unlike in relatively healthy patients, late atrial potential predominance was seen (63 % vs. 84 %; P = 0.0419) with a 16.4 times (P = 0.018) increase in the number of premature atrial contractions. Also, in patients with AH without concomitant subclinical hypothyroidism late ventricular potentials (LVPs) occurred 5.7 times more often (6 % vs. 34 %, P = 0.0302) and were associated with a significant (P = 0.004) increase in the number of premature ventricular contractions per day in this category of patients.In SH patients with a concomitant subclinical hypothyroidism, unlike in relatively healthy individuals, atrial ectopic activity was significantly more predominant (LAP was found in 87 %; versus 63 %, P = 0.0498), which was accompanied by a logical 27.2 times (P = 0.038) increase in the number of premature atrial contractions and ventricular ectopic activity. Changes in the electrical properties of the ventricles were accompanied by an increase in the percentage of detected LVPs (77 % versus 6 %, P = 0.0001), which was associated with a significant (P = 0.001) increase in the number of premature ventricular contractions per day in this category of patients (441.53 ± 1414.97 versus 0.00 ±0.00 inalmost healthy subjects, P = 0.001).AH patients with and without concomitant SH did not differ from each other in terms of indexes characterizing late atrial potentials. There was also no statistically significant difference in the number of premature atrial contractions (P = 0.527), paired premature atrial contractions (P = 0.449), salvos of atrial premature contractions (P = 0.314). However, in AH patients with concomitant SH there was a significant increase in the ectopic activity of the ventricles – LVPs were found in 77 % vs. 33 % in individuals without SH (P = 0.0001), changes in the electrical properties of ventricles in AH patients with concomitant SH were also associated with an increase in the number of premature ventricular contractions by 6.69 times (from 42.56 ± 36.96 to 441.53 ± 1414.97, P = 0.026) compared with the same index in patients with AH without concomitant SH, indicating the negative effect of SH on the electrical properties of the ventricles.Conclusions. In patients with stage II arterial hypertension in comparison to relatively healthy subjects, indicators that characterize the late potentials of the atria and ventricles are significantly changed, which is accompanied by an increase in the number of supraventricular and ventricular rhythm disorders. Subclinical hypothyroidism causes an additional pro-arrhythmic effect on the ventricular myocardium in arterial hypertension.

Acute effect of a peritoneal dialysis exchange on electrolyte concentration and QT interval in uraemic patients.

Hemodialysis (HD) sessions induce changes in plasma electrolytes that lead to modifications of QT interval, virtually associated with dangerous arrhythmias. It is not known whether such a phenomenon occurs even during peritoneal dialysis (PD). The aim of the study is to analyze the relationship between dialysate and plasma electrolyte modifications and QT interval during a PD exchange. In 15 patients, two manual PD 4-h exchanges were performed, using two isotonic solutions with different calcium concentration (Ca++1.25 and Ca1.75++mmol/L). Dialysate and plasma electrolyte concentration and QT interval (ECG Holter recording) were monitored hourly. A computational model simulating the ventricular action potential during the exchange was also performed. Dialysis exchange induced a significant plasma alkalizing effect (p < 0.001). Plasma K+ significantly decreased at the third hour (p < 0.05). Plasma Na+ significantly decreased (p < 0.001), while plasma Ca++ slightly increased only when using the Ca 1.75++mmol/L solution (p < 0.01). The PD exchange did not induce modifications of clinical relevance in the QT interval, while a significant decrease in heart rate (p < 0.001) was observed. The changes in plasma K+ values were significantly inversely correlated to QT interval modifications (p < 0.001), indicating that even small decreases of K+ were consistently paralleled by small QT prolongations. These results were perfectly confirmed by the computational model. The PD exchange guarantees a greater cardiac electrical stability compared to the HD session and should be preferred in patients with a higher arrhythmic risk. Moreover, our study shows that ventricular repolarization is extremely sensitive to plasma K+ changes, also in normal range.

Left ventricular geometry correlates with early repolarization pattern in adolescent athletes.

Some forms of early ECG repolarization QRS pattern (ERp) with J-point elevation of 0.1mV in two contiguous inferior and/or lateral leads with or without ST-elevation are potentially associated with a higher arrhythmic risk in adults. We assessed the prevalence of ERp among non-professional adolescent athletes and correlated it with age, sex, ethnicity, and structural and electric cardiac parameters. We retrospectively analyzed 414 ECGs obtained from young athletes referred to our center from 2006 to 2017. We found ERp in 22% of cases. In the ERp group, we found a greater percentage of black athletes, a higher systolic blood pressure, and lower heart rate (HR) compared with the group without ERp. This pattern was less frequent in female athletes. In athletes with ERp, the occurrence of ventricular ectopic beats was less frequent and QRS-duration was shorter. They also exhibited greater (a) ECG-based left ventricular hypertrophy (LVH), (b) left ventricular mass, and (c) relative wall thickness (RWT), suggesting a tendency to concentric geometry. At logistic regression analysis, we found that HR (OR 0.98 [0.96-0.99] P=.013), QRS-duration (OR 0.96 [0.94-0.99], P=.003), LVH (OR 1.09 [1.05-1.12], P<.001), and RWT (OR 1.08 [1.01-1.16] P=.032) were significant predictors of ERp incidence. ERp is quite common in adolescent athletes and correlates with concentric LV remodeling. Specific clinical and ECG-findings related to training such as lower HR, LVH, and QRS-duration are also predictors of ERp. In adolescent non-professional athletes, ERp is a benign finding associated with some structural and electric cardiac modifications induced by training.