Myocardial Electrical Instability Research Articles

Fragmented QRS in patients with preeclampsia.

This study aims to investigate the prevalence, clinical correlates, and prognostic implications of fragmented QRS complexes (fQRS) in pregnant women with preeclampsia (PE), shedding light on the potential role of electrocardiographic markers in identifying cardiac involvement in hypertensive disorders of pregnancy. Patients with PE and age-matched low-risk control patients were recruited at a tertiary hospital between January 2015 and January 2023. A comprehensive assessment, including heart rate, PR duration, QRS duration, corrected QT duration, and fragmented QRS, was conducted by 12-lead electrocardiography. Baseline clinical characteristics, laboratory parameters, and electrocardiographic findings were compared between the study groups. 128 preeclampsia patients and 122 age- and comorbidity-matched controls were included in the study. The prevalence of fQRS was significantly higher in preeclamptic women compared to normotensive controls (14.1% vs. 3.3%, p = 0.04). ALT levels of pregnant women with preeclampsia and without preeclampsia groups were 43,77 (35.25-48.22) and 23,18 (13.75-33.00) (p: 0.038), respectively. In univariate regression analyses, Na and fragmented QRS were found to be associated with preeclampsia. (p: 0.016 and 0.009, respectively). After multivariable adjustment for variables, Na and fragmented QRS remained strongly associated with preeclampsia (OR: 4.787 (1.556-14.720), p: 0.06; 0.941 (0.893-0.992), p: 0.023, respectively). This study provides compelling evidence of an association between preeclampsia and fragmented QRS complexes, implicating electrolyte imbalances and hemodynamic stress as potential contributors to myocardial electrical instability in hypertensive disorders of pregnancy. Further research is warranted to validate these findings and improve risk stratification and clinical outcomes in affected women. Number: 2023/4705 Retrospectively Registered.

Applied Cardio-Oncology in Hematological Malignancies: A Narrative Review.

Applied cardio-oncology in hematological malignancies refers to the integration of cardiovascular care and management for patients with blood cancer, particularly leukemia, lymphoma, and multiple myeloma. Hematological cancer therapy-related cardiotoxicity deals with the most common cardiovascular complications of conventional chemotherapy, targeted therapy, immunotherapy, chimeric antigen receptor T (CAR-T) cell and tumor-infiltrating lymphocyte therapies, bispecific antibodies, and hematopoietic stem cell transplantation. This narrative review focuses on hematological cancer-therapy-related cardiotoxicity's definition, risk stratification, multimodality imaging, and use of cardiac biomarkers to detect clinical and/or subclinical myocardial dysfunction and electrical instability. Moreover, the most common cardiotoxic profiles of the main drugs and/or therapeutic interventions in patients with hematological malignancies are described thoroughly.

Connexin43, A Promising Target to Reduce Cardiac Arrhythmia Burden in Pulmonary Arterial Hypertension.

While essential hypertension (HTN) is very prevalent, pulmonary arterial hypertension (PAH) is very rare in the general population. However, due to progressive heart failure, prognoses and survival rates are much worse in PAH. Patients with PAH are at a higher risk of developing supraventricular arrhythmias and malignant ventricular arrhythmias. The latter underlie sudden cardiac death regardless of the mechanical cardiac dysfunction. Systemic chronic inflammation and oxidative stress are causal factors that increase the risk of the occurrence of cardiac arrhythmias in hypertension. These stressful factors contribute to endothelial dysfunction and arterial pressure overload, resulting in the development of cardiac pro-arrhythmic conditions, including myocardial structural, ion channel and connexin43 (Cx43) channel remodeling and their dysfunction. Myocardial fibrosis appears to be a crucial proarrhythmic substrate linked with myocardial electrical instability due to the downregulation and abnormal topology of electrical coupling protein Cx43. Furthermore, these conditions promote ventricular mechanical dysfunction and heart failure. The treatment algorithm in HTN is superior to PAH, likely due to the paucity of comprehensive pathomechanisms and causal factors for a multitargeted approach in PAH. The intention of this review is to provide information regarding the role of Cx43 in the development of cardiac arrhythmias in hypertensive heart disease. Furthermore, information on the progress of therapy in terms of its cardioprotective and potentially antiarrhythmic effects is included. Specifically, the benefits of sodium glucose co-transporter inhibitors (SGLT2i), as well as sotatercept, pirfenidone, ranolazine, nintedanib, mirabegron and melatonin are discussed. Discovering novel therapeutic and antiarrhythmic strategies may be challenging for further research. Undoubtedly, such research should include protection of the heart from inflammation and oxidative stress, as these are primary pro-arrhythmic factors that jeopardize cardiac Cx43 homeostasis, the integrity of intercalated disk and extracellular matrix, and, thereby, heart function.

Individual typological approach to the analysis of the body function of medical students

Aim. Rationale of the individual typological approach in the analysis of the body function of medical students.Material and methods. In students with moderate (Group I) and high (II Group) dominance of central regulation, with moderate (III Group) and high (IV Group) predominance of autonomous regulation, a comparative analysis of heart rate variability parameters, the functional state of the myocardium and the central nervous system was carried out.Results. We found that 53,3% of group III students had no deviations in myocardial function. There were the maximum values of nervous response stability (2,0 [1,5-2,3] units) and functional capability of the nervous system (3,3, [2,7-3,5] units) relative to students of other groups, as well as the formation of normal and slightly reduced mental performance (93,6%), satisfactory biological adaptation (33,3%). In group II students, relative to group III students, there were an increase in the "myocardium" index by 1,2 times, "rhythm" index by 1,8-1,9 times, T wave alternans by 1,3 times and myocardial electrical instability by 2 times, as well as a decrease in nervous system stability by 2,5 times, its functionality by 1,7 times, the formation of reduced performance (55,6%) and unsatisfactory biological adaptation (35,2%). In group IV students, the functional state was characterized by heart rhythm dysregulation (94,1%), borderline myocardial function deviations (76,5%), and a 1,7-fold decrease in nervous reaction stability and 1,3-fold decrease functional capability of the nervous system relative to group III students, reduced performance (38,5%) and unsatisfactory biological adaptation (58,8%).Conclusion. Differentiation of students depending on the individual typological characteristics of the autonomic heart rate regulation makes it possible to identify students at risk with a pronounced dominance of autonomous and central heart rate regulation, which becomes the starting point for the implementation of differentiated methods of wellness education.

Arrhythmias in patients with acute ST-elevation myocardial infarction induced by various risk factors during the first day after myocardial reperfusion by primary percutaneous coronary intervention

Introduction. Acute coronary syndrome, in particular acute ST-elevation myocardial infarction (STEMI), is often accompanied by complex hemodynamically significant arrhythmias and conduction disorders. Such patients have a worse prognosis compared to patients with sinus rhythm. Arrhythmias in patients with STEMI are facilitated by the presence of comorbidities such as arterial hypertension, diabetes mellitus, obesity, and post-COVID-19 syndrome. The aim of the study. To elucidate the nature of arrhythmias in patients with acute STEMI induced by various risk factors during the first day after myocardial reperfusion by primary percutaneous coronary intervention. Materials and methods. The study involved 50 patients aged 45 to 83 years (average age – 63,4 ± 9,6 years; men – 70,97 %, women – 29,03 %), who were treated during 2021-2023 at the cardiology and reperfusion therapy department of Cardio-vascular center of ʺSaint Panteleimon Hospital in Lvivʺ and the infarction department of ʺLviv Regional Clinical Cardiological Centerʺ. The patients under investigation were subjected to daily electrocardiogram (ECG) monitoring for 24 hours after stenting of the infarct-related coronary artery, using a 7-channel ECG recorder Solvaig 06000.7 with computer processing of the recording using the DiaCard2 software. The obtained material was further subjected to software packages Microsoft Excel 2022, Statistica 10. Results. It was established that among supraventricular rhythm disturbances the most common were premature contractions, the average number of which per patient was significantly higher in the presence of obesity. Similarly high it was in post COVID-19 patients, as well as in those with hypertension. In post-coronavirus infection and in hypertension cases, extrasystoles were often in the form of pairs, triplets, bigemia, and trigemia; paroxysms of supraventricular tachycardia were also recorded in these patients. Among the ventricular arrhythmias also the most frequent were premature cardiac contractions, significantly more oftenly recorded in patients with hypertension and those experienced COVID-19; only in these patients were documented extrasystoles in the form of pairs, triplets, bigeminy, trigeminy, runs of ʺR to Tʺ, which are currently considered as harbingers of life-threatening ventricular arrhythmias. In the presence of hypertension and post-COVID-19, episodes of unstable ventricular tachycardia were also observed. Conclusions. In patients with STEMI, both supraventricular and ventricular premature contractions and episodes of supraventricular and unstable ventricular tachycardia are quite common during the first day after primary percutaneous coronary intervention with infarct-related coronary artery stenting, which is evidence of myocardial electrical instability. The nature of rhythm disturbances in the presence of hypertension and post-COVID-19 is prognostically unfavorable and indicates a higher risk of lifethreatening arrhythmias in these patients. Myocardial revascularization should be supplemented with optimal medical treatment in order to prevent the adverse cardiovascular events in post-STEMI patients. Further research should be directed toward elucidation of predictive value of detected arrhythmias with respect to the occurrence of unfavorable cardiovascular events in the early and long-term post-infarction period.

Abstract 11663: T Wave Alternans: A Clue in Plain Sight

Introduction: T-wave alternans (TWA) refers to the beat-to-beat variability in T-wave amplitudes or polarity on surface ECGs, and can signify susceptibility to malignant ventricular arrhythmias (VA). Aims: We present a case to emphasize the pathophysiology and clinical significance of this ECG finding. Case description: A 52 year-old female with history of HIV presents with shortness of breath and is treated for heart failure. In the ED, she has witnessed syncope and is found to have VT that progresses to VF. Resuscitation efforts are successful and include amiodarone loading. Figure 1A demonstrates baseline ECG on admission with a QTc of 495 ms. A few days later, an ECG reveals QTc of 696 ms with TWA (figure 1B). Shortly after, she develops polymorphic VT in the setting of long-short sequences and an R on T trigger (figure 1C) that is terminated with cardioversion. Review of pre-admission ECGs reveals that QTc prolongation occurred after initiation of a retroviral regimen that included rilpivirine and worsened with amiodarone. Both medications are discontinued, and she is eventually discharged with a QTc of 450 ms. Early theories for TWA's mechanism hypothesized that dispersion of refractoriness resulted in depolarization through alternating pathways and thus this phenomenon. Recent understanding further suggests that TWA occurs as a result of cellular alternans and variation in action potential duration due to dysregulation of repolarization. If discordant repolarization alternans ensues, whereby neighboring cells repolarize in opposite phases (long-short, short-long), the resultant repolarization gradient and heterogeneity in cellular repolarization serves as the substrate for VA; if a premature beat encounters refractory myocardium and unidirectional block occurs, a re-entrant excitation tachycardia can be initiated. Conclusions: TWA on ECG suggests myocardial electrical instability as a result of cellular repolarization inhomogeneity.

Analysis of the results of functional diagnostic studies of the cardiovascular system in children after surgical correction of congenital heart defects

Objective. To evaluate the features of the cardiovascular system in children after surgical correction of congenital heart defects revealed by functional diagnostic studies.Materials and methods. A functional diagnostic examination of the cardiovascular system (CVS) was performed in 43 children aged 5 to 17 years with the main clinical diagnosis: “Congenital heart disease” (CHD), of which 33 children of the main group (MG) had corrected CHD, in 10 children of the comparison group (CG) CHD correction was not performed due to the presence of certain contraindications. Patients were on a routine examination and treatment for CHD in the cardio-rheumatology department of the institution “Gomel Regional Children’s Clinical Hospital” in the period 2020-2022.Results. Based on the statistical processing of the results of the study, which included an assessment of clinical and anamnestic data and indicators of functional diagnostic methods for examining the CVS in children with CHD, the need for a comprehensive cardiological examination in children with this pathology was established, regardless of the method of performed surgical intervention. It was found that the majority of children with corrected CHD on the ECG had rhythm and conduction disturbances, as well as combined arrhythmias, and one third of the patients had cardiac complaints. According to the Holter monitoring (HM) and bicycle ergometry (BEM) tests, the children showed signs of electrical instability of the myocardium and a decrease in the adaptive reserves of the cardiovascular system.Conclusion. Children with corrected CHD require a comprehensive functional and diagnostic examination, which makes it possible to identify an “arrhythmogenic substrate” and establish signs of myocardial electrical instability, thereby optimizing the tactics of treatment and rehabilitation of this group of patients.

Indicators of myocardial electrical instability during high-dose atorvastatin therapy in patients after acute myocardial infarction in combination with COVID-19

Indicators of myocardial electrical instability during high-dose atorvastatin therapy in patients after acute myocardial infarction in combination with COVID-19

Electrocardiographic patterns of autonomic dysfunction in the diagnosis of autonomic neuropathy in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus poses a serious threat to the health of people worldwide. Despite active detection and stringent measures to control and treat diabetes, the condition leads to a variety of complications, including autonomic neuropathy, resulting in autonomic cardiac denervation associated with an increased risk of painless myocardial ischemia and sudden cardiac death. However, digital verification by finding electrocardiographic (ECG) patterns of autonomic dysfunction is possible.
 The available literature on ECG patterns of myocardial electrical instability, which reflect autonomous myocardial dysfunction, was summarized. A literature review of scientific papers on ECG diagnosis of autonomic myocardial dysfunction in patients with type 2 diabetes mellitus over the past 5 years was performed using PubMed and eLIBRARY data.
 Among different ECG patterns that reflect autonomic dysfunction, the most common is the investigation of heart rhythm variability, which is based on the mathematical analysis of respiration rate intervals. The simplest variables are used to obtain a series of statistical indicators such as SDANN, RMSSD, NN50, and pNN50. A new and understudied ECG pattern of autonomic dysfunction is heart rate turbulence (HRT), which is a short-term rhythm change that develops in response to a ventricular extrasystole. The extrasystole is followed by a short episode of sinus tachycardia lasting several cardiac cycles, which is followed by a longer episode of bradycardia. These heart rate fluctuations are based on baroreflex compensation of intracardiac hemodynamic changes. Two parameters are estimated to characterize the HRT: turbulence onset and turbulence slope. A specific marker of autonomic dysfunction is the rate of cardiac rhythm recovery after controlled exercise. A recovery rate of 12 beats per first minute was associated with an increased risk of all-cause mortality, whereas a reduction in recovery rate of 40 beats per 2 min was found to be a strong independent risk factor for all-cause mortality.
 An imbalance in the tone of sympathetic and parasympathetic systems underlies all the described indicators. Therefore, a risk-stratifying significance of autonomic dysfunction markers in a wide range of pathologies, including peptic ulcer disease, gallstone disease, hypertension, chronic heart failure, chronic obstructive pulmonary disease, bronchial asthma, thyreopathies, and anemias apart from type 2 diabetes mellitus, exists. This explains the high sensitivity of tests, while having a low positive predictive value and specificity. The ease of performing tests dictates the need for further study of the features of autonomic dysfunction markers in patients with type 2 diabetes mellitus, since these markers are associated with a high risk of painless myocardial ischemia and sudden cardiac death.
 Currently, several ECG patterns (heart rate variability, HRT, and heart rate recovery rate) reflect autonomous myocardial dysfunction. The patterns enable early detection of autonomous neuropathy in patients with type 2 diabetes mellitus, which will allow timely diagnosis and adequate therapy. However, further study is required due to their low specificity to identify the peculiarities in specific nosological forms.

Parameters Of Myocardial Electrical Instability In Patients After Myocardial Infarction Comorbid With A Novel Coronavirus Infection (COVID-19)

Objective — This article aims to assess parameters of myocardial electrical instability and arrhythmic events in patients after myocardial infarction (MI), with and without ST-segment elevation, comorbid/noncomorbid with a novel coronavirus infection (COVID-19) using a long-term electrocardiographic (ECG) monitoring. Methods — The study included 64 subjects: 25 (39%) patients with MI comorbid with COVID-19 (MI+C group) and 39 (61%) patients with MI noncomorbid with a novel coronavirus infection (MI group). The mean age of patients was 54.3±6.8 years. A long-term ECG monitoring for 97.4 (95% CI 77.9-115.2) hours was performed with Astrocard®-Telemetry system (Meditek JSC, Russia), starting from the 4th day of MI. Rhythm and conduction disorders, along with ischemic episodes were recorded; an analysis of ventricular late potentials, heart rate turbulence, and QT dispersion was carried out. Results — There were no differences in the frequency of delayed afterdepolarizations in MI and MI+C groups: 15-28% and 18-33% of patients, respectively. An analysis of turbulence parameters did not reveal statistically significant differences between the groups. Such arrhythmic events as frequent supraventricular extrasystole and life-threatening arrhythmias (ventricular extrasystole of grade 4A and higher sensu B. Lown and M. Wolf) were recorded significantly more often in the MI+C group than in the MI group: 48% vs. 20.5% (p=0.021) and 24% vs. 5.1% (p=0.026), respectively. Conclusion — The novel coronavirus infection (COVID-19) exacerbates myocardial electrophysiological heterogeneity in the acute cardiovascular event and is associated with an increase in clinically significant arrhythmic events.

Capabilities of long-term ECG monitoring in patients with myocardial infarction: the longer, the better?

Background. In modern cardiology, 24-hour electrocardiogram (ECG) monitoring has a high diagnostic value, but this method has a number of disadvantages in detecting episodes of unstable life-threatening arrhythmias. An increase in ECG monitoring duration allows expanding the possibilities of diagnosing life-threatening arrhythmias.Objective. To study the possibilities of long-term ECG monitoring (48–120 hours) in the detection of life-threatening arrhythmic events and parameters of myocardial electrical instability in patients with ST-segment elevation myocardial infarction (STEMI).Design and methods. The study included 71 STEMI patients. All patients from the 4th day of STEMI underwent multi-day ECG monitoring in 3 leads using a telemetric ECG recording complex with an average recording duration of 90.4 ± 30.2 hours. The analysis of episodes of myocardial ischemia, rhythm and conduction disturbances, turbulence and heart rate variability, late ventricular potentials and dispersion of the QT interval within 5 days was carried out.Results. Long-term monitoring allowed detecting high-grade ventricular extrasystoles. Analysis of episodes of myocardial ischemia in the postinfarction period revealed significant differences in the data of 120h-ECG monitoring in comparison with 24h-ECG. Multiday ECG monitoring made it possible to detect dysfunction of the autonomic regulation of cardiac activity in patients 2 times more often.Conclusion. A comprehensive assessment of the possibilities of multi-day ECG monitoring is a promising direction in predicting severe arrhythmias in patients in the postinfarction period.

PECULIARITIES OF HEART RHYTHM DISORDERS AND VENTRICULAR REPOLARIZATION STATUS IN PATIENTS WITH MYOCARDIAL INFARCTION WITHOUT ELEVATION OF SEGMENT ST DEPENDING ON THE INDICATORS OF STRUCTURAL REMODELING OF THE LEFT VENTRICLE

SUMMARY. Despite advances in the treatment of acute myocardial infarction in most developed countries, this pathology remains the leading cause of morbidity and mortality. The search for opportunities to predict the development of complications, study of remodeling processes and their impact on the development of electrical instability of the myocardium is currently considered as a promising area of non-invasive diagnosis of myocardial infarction. The aim – to establish the features of cardiac arrhythmias and the condition of ventricular repolarization in patients with NSTEMI depending on the indicators of structural remodeling of the left ventricle. Material and Methods. We conducted a comprehensive study of 200 patients with NSTEMI aged 38 to 80 years. All patients were examined according to the current protocol of diagnosis and treatment of patients with acute coronary syndrome without ST-segment elevation and daily Holter ECG monitoring was performed for 3–5 days after hospitalization. Results. An increase in the left ventricular myocardial mass index and a change in the geometric model are associated with an increase in the probability of developing myocardial electrical instability, in particular extrasystoles of any topic and paroxysmal tachycardia. At the same time, changes in structural remodeling indicators did not reveal correlations with ventricular repolarization disorders in the early NSTEMI period. Conclusions. Evaluation of the indicators of structural remodeling of the ventricular myocardium in the early period of NSTEMI allows to predict the risk of electrical instability of the myocardium and to carry out appropriate preventive measures.

Factors of Cardiovascular Risk in Drivers of Locomotive Crews of Railway Transport with Ventricular Arrhythmias

AIM: This study aimed to assess cardiovascular risk factors in drivers and assistant drivers of railway engine crews with ventricular rhythm disorders.
 MATERIALS AND METHODS: The study included 120 patients aged 39 to 61 years (mean age M SD: 50.4 4 years), who were distributed into two groups with and without ventricular rhythm disorders. All participants underwent 12-lead daily ECG monitoring with assessment of noninvasive markers of myocardial electrical instability (circadian profile, QT interval, late ventricular potentials, T-wave alternation, rhythm variability). Traditional factors of cardiovascular risk, the employment period in the profession, and the level of personal and situational anxiety on Spielbergers state-trait anxiety inventory (STAI) were evaluated.
 RESULTS: In Group 1, in comparison with Group 2, significant differences were revealed in the duration of the PQ interval (during the day and at night) and the indicators of late ventricular potentials (RMS 40 and TotQRSF). When analyzing risk factors, elevated indices of total blood cholesterol were registered in both groups, and the risk on the SCORE scale was at a moderate level. In the group of workers with ventricular rhythm disorders, higher indicators of total blood cholesterol and the frequency of smoking and alcohol consumption were established. In individuals with ventricular rhythm disorders, a significant relationship was detected between the number of registered single monomorphic ventricular extrasystoles and the age of the employee (r = 0.3, р 0.05), and blood pressure level (r = 0.3, р 0.05), and the relationship between the level of anxiety and the registration of single supraventricular extrasystoles was established (r = 0.3, р 0.05). In the Group 2, a significant correlation was revealed between the number of registered single supraventricular extrasystoles and age (r = 0.2, р 0.05), the employment period in the profession of a driver (r = 0.2, р 0.05), the blood pressure level (r = 0.2, р 0.05), and the level of anxiety on the STAI (r = 0.3, р 0.05).
 CONCLUSIONS: Drivers of railway engine crews with ventricular rhythm disorders are characterized by a higher level of total blood cholesterol and a higher frequency of smoking and alcohol consumption. They have significant changes in the duration of the PQ interval (during the day and at night) and indicators of late ventricular potentials (RMS 40 and TotQRSF) according to Holter monitoring. The relationship of the number of ventricular rhythm disorders with age and the office values of systolic and diastolic blood pressure is noted in drivers of engine crews of railway transport.

PECULIARITIES OF HEART RHYTHM DISORDERS AND VENTRICULAR REPOLARIZATION STATUS IN PATIENTS WITH MYOCARDIAL INFARCTION WITHOUT ST SEGMENT ELEVATION DEPENDING ON THE INDICATORS OF STRUCTURAL REMODELING OF THE LEFT VENTRICLE

Resume. Despite advances in the treatment of acute myocardial infarction in most developed countries, this pathology remains the leading cause of morbidity and mortality. The search for opportunities to predict the development of complications, study of remodeling processes and their impact on the development of electrical instability of the myocardium is currently considered as a promising area of ​​non-invasive diagnosis of myocardial infarction. Aim. To establish the features of cardiac arrhythmias and the condition of ventricular repolarization in patients with NSTEMI depending on the indicators of structural remodeling of the left ventricle. Materials and methods. We conducted a comprehensive study of 200 patients with NSTEMI aged 38 to 80 years. All patients were examined according to the current protocol of diagnosis and treatment of patients with acute coronary syndrome without ST-segment elevation and daily Holter ECG monitoring was performed for 3-5 days after hospitalization. Results. An increase in the left ventricular myocardial mass index and a change in the geometric model are associated with an increase in the probability of developing myocardial electrical instability, in particular extrasystoles of any topic and paroxysmal tachycardia. At the same time, changes in structural remodeling indicators did not reveal correlations with ventricular repolarization disorders in the early NSTEMI period. Conclusions. Evaluation of the indicators of structural remodeling of the ventricular myocardium in the early period of NSTEMI allows to predict the risk of electrical instability of the myocardium and to carry out appropriate preventive measures.

Relationship between electrical myocardial instability and postinfarction remodeling in patients with ST-segment elevation myocardial infarction.

Aim To study the clinical value of markers for myocardial electrical instability in combination with echocardiographic parameters for predicting the risk of cardiovascular complications (CVC) in the postinfarction period.Material and methods This study included 118 patients with ST segment elevation myocardial infarction (STEMI) and hemodynamically significant stenosis of one coronary artery. A percutaneous coronary intervention (PCI) with stenting of the infarct-related artery was performed for all patients. On day 7-9 and at 24 and 48 weeks after the treatment, ECG Holter monitoring was performed, which included analyses of ventricular late potentials, dispersion of QT interval duration, heart rate turbulence (HRT) and variability (HRV), and heart chronotropic load (HCL). At baseline and during postinfarction week 12, all patients underwent echocardiography with calculation of indexes of end-diastolic volume (iEDV) and end-systolic volume (iESV) to verify the signs of left ventricular (LV) myocardial remodeling. The criteria for LV pathological remodeling included increases in iEDV >20 % and/or iESV >15 % at 12 weeks after STEMI. The group without remodeling, R(-), consisted of 79 (67 %) patients and the group with signs of LV pathological remodeling, R(+), consisted of 39 (33 %) patients. Quality of life and achieved endpoints were evaluated during 144 weeks.Results By week 48 in group R(-), the stabilization of electrical processes in the myocardium was more pronounced as indicated by a decrease in HFLA by 12 % (р=0.004) and by a fourfold increase in RMS (р=0.047). Only in this group, the baroreflex sensitivity restored; pathological ТРС decreased from 20 to 5% (p=0.002) by the end of the active treatment. Stabilization of the repolarization phase duration in various parts of the myocardium was more active in patients without pathological remodeling as shown by decreases in disp QTa (р=0.009), disp QTe (р=0.03), sd QTa (р=0.006), and sd QTe (р=0.009). This was not observed in the group R(+). The recovery of vagosympathetic balance due to leveling the sympathetic component also was more effective in the group R(-), which was reflected in increased spectral and temporal HRV indexes (р<0.05). Both groups showed reduced HCL values at 24 weeks (р=0.047 and р=0.006); however, the HCL regression remained also at 48 weeks only in the group R(-) (р=0.006). Group R(-) patients reported higher quality of life (р=0.03) than group R(+) patients. Endpoints were achieved more frequently in the group R(+): 87.1 % vs. 27.8 % (odds ratio, 11.8; 95 % confidence interval, 4.6-30.8; р=0.00001).Conclusion Pathological myocardial remodeling in early postinfarction period is associated with electrophysiological instability of the myocardium, which results in the development of CVC and low quality of life in patients with STEMI.

Sympatho-adrenergic mechanisms in heart failure: new insights into pathophysiology.

The sympathetic nervous system is activated in the setting of heart failure (HF) to compensate for hemodynamic instability. However, acute sympathetic surge or sustained high neuronal firing rates activates β-adrenergic receptor (βAR) signaling contributing to myocardial remodeling, dysfunction and electrical instability. Thus, sympatho-βAR activation is regarded as a hallmark of HF and forms pathophysiological basis for β-blocking therapy. Building upon earlier research findings, studies conducted in the recent decades have significantly advanced our understanding on the sympatho-adrenergic mechanism in HF, which forms the focus of this article. This review notes recent research progress regarding the roles of cardiac β2AR or α1AR in the failing heart, significance of β1AR-autoantibodies, and βAR signaling through G-protein independent signaling pathways. Sympatho-βAR regulation of immune cells or fibroblasts is specifically discussed. On the neuronal aspects, knowledge is assembled on the remodeling of sympathetic nerves of the failing heart, regulation by presynaptic α2AR of NE release, and findings on device-based neuromodulation of the sympathetic nervous system. The review ends with highlighting areas where significant knowledge gaps exist but hold promise for new breakthroughs.

Electric myocardial inhomogeneity and stroke: connection and specifics

Abstract Funding Acknowledgements Type of funding sources: None. Background. The inconsistency of the literature data on the influence of different hemispheric localization of Cerebrovascular accident (CVA) on the development of cardiac arrhythmias suggests the expediency of further study of the so-called "zones" of the cerebral cortex associated with electrical instability of the myocardium. It is known that dispersion of QT interval and fragmented myocardial activity belong to the markers of electrical instability of the heart and are associated with arrhythmogenesis. The aim of the study. To study the severity of abnormalities of the parameters of electrical instability of myocardium in right and left hemispheric stroke localization in patients with hypertension. Material and methods. 111 patients with left hemispheric localization of ischemic stroke and 75 patients with right hemispheric stroke were examined. Hemorrhagic stroke was observed in 17 patients in the left hemisphere and in 13 patients in the right hemisphere. The average age was 58,2 ± 7,48 years. For all strokes, men prevailed (64% vs. 36%). For the first day of the stroke, all patients were evaluated for QT dispersion and fragmented myocardial activity on the device "Polyspectro-8EX" (Russia). Research results. Evaluation of the parameters of electrical instability of myocardium in patients with stroke revealed more pronounced disorders in hemorrhagic stroke of left hemispheric localization (Table 1). In ischemic stroke, the severity of electrophysiological parameters, reflecting the instability of the myocardium depending on the hemispheric localization, indicates the absence of differences. Conclusions. 1.The most pronounced disturbances in the parameters of electrical stability of the myocardium is observed in hemorrhagic stroke. 2.The severity of myocardial electrical instability in ischemic stroke is not associated with the localization of the focus.

The role of fibrosis biomarkers in predicting the development of myocardial electrical instability (a literature review)

The aim. To analyze scientific researches on studying the biomarkers of fibrosis based on a review of the most recent publications for the possibility to predict electrical myocardial instability development. In total, 101 sources of literature related to the role of fibrosis biomarkers in the past 5 years were analyzed. The review of the literature has shown that myocardial fibrosis іs considered to be an arrhythmogenic substrate for ventricular arrhythmias, as it provides structural and functional disorders of the cardiac electrical activity. Markers of fibrosis, which are measured in cardiac pathology, allow determining the risk of electrical myocardial instability, which is a pathophysiological mechanism underlying sudden arrhythmic death. Conclusions. Markers of fibrosis such as aldosterone, galectin-3 and transforming growth factor-β1, which are measured in heart failure, hypertension, metabolic syndrome, myocardial infarction, atrial fibrillation, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, have been found to predict myocardial electrical instability. Prediction of myocardial electrical instability in patients with hypertension and coronary heart disease based on studies of the association between frequent ventricular arrhythmias and plasma biomarkers of fibrosis (aldosterone, galectin-3, and transforming growth factor-β1) has not been discussed in the literature.

A Digital Electrocardiographic System for Assessing Myocardial Electrical Instability: Principles and Applications.

The aim of the study was to develop an ECG hardware and software system for monitoring electrical instability of the myocardium and to assess the diagnostic and prognostic capabilities of this setup in a cardiology clinic.Materials and Methods.The Intecard 7.3 software and hardware system developed in this study makes it possible to measure fluctuations of the ECG amplitude-time parameters using the beat-to-beat mode. Intecard 7.3 evaluates a number of ECG markers that reflect electrical instability of the myocardium. Among them are the fragmented QRS complex, the spatial QRS-T angle, the T-wave alternans, the duration, and dispersion of the QT interval, the turbulence and acceleration/deceleration of the heart rhythm.Clinical trials of Intecard 7.3 were carried out with 734 patients with ischemic heart disease or cardiomyopathy and 112 healthy individuals.Results.Intecard 7.3 reliably identifies fragmented QRS complexes by detecting short spikes of <25 ms in the ascending parts of the Q, R, and S waves. The QRS-T angle is determined from the reference amplitudes of the R and T waves in leads avF, V2, V5, and V6. Digital precision processing of the ECG signal improves its accuracy to microvolts and microseconds.The software was designed to measure the T-wave amplitude in each of 300–500 cardiobeats; T-wave alternans was estimated by the moving average method. In a typical cardiobeat, the QT dispersion was calculated based on 12 ECG leads. From the sequence of RR intervals, turbulence, and deceleration of the heart rhythm were determined.During the observation period of 5.0 [2.1; 5.9] years, 90 out of 734 patients (12.3%) experienced adverse cardiovascular events (ACVE). In this period, the myocardial electrical instability was recorded in patients with ACVE more frequently than in those without ACVE. Thus, the frequency of fragmented QRS was 72.2±4.7 vs 16.8±1.5% (p<0.01), the values of the QRS-T angle were 128 [55; 101] vs 80 [53; 121]° (p<0.001), the T-wave alternans — 36.9 [15.5; 62.1] vs 21.9 [10.2; 30.7] μV (p<0.005), the QT interval — 408 [383; 438] vs 376 [351; 400] ms (p<0.001), the QT dispersion — 76 [57; 96] vs 64 [50; 92] ms (p<0.005), respectively. In patients with ACVE, the threshold that triggers pathological rhythm turbulence was higher (>0%) than that in healthy controls (p<0.001); the deceleration of the heart rhythm was reduced from 19.2 [2.2; 38.0] to 8.8 [4.0; 16.8] ms (p<0.05).A personalized model for ACVE risk stratification has been developed. In this model, the area under the ROC curve was 0.856; sensitivity — 75%; specificity — 78%; predictive accuracy — 77%.Conclusion.Using the ECG markers of myocardial electrical instability, the Intecard 7.3 system allows one to predict life-threatening ventricular tachyarrhythmias and sudden cardiac death with an accuracy of 77%. The non-invasiveness, high productivity, and reasonable cost ensure the availability of this predictive technology in all levels of healthcare.

Program «Smart ECG – ranolazin» - own experience and world approach

Purpose - comprehensive analysis of the world approach of the use of ranolazine in various clinical trials and the introduction of the program "Smart ECG" to assess the effectiveness of ranolazine.Matherial and methods. Evaluation of European guidelines, analysis of global randomized clinical trials of the ranolazine use, presentation of our own trial: we examined 40 patients with Q wave myocardial infarction (STEMI), were instituted basic therapy according to the modern recommendations which contained interventional treatment with restoration of patency of a heart attack-conditioned coronary artery, double antiplatelet therapy, statins, β-adrenergic blocker, angiotensin-converting enzyme inhibitors, aldosterone antagonists with addition of ranolazine (group I, 30 patients diagnosed STEMI), control - group II, 10 patients with STEMI, who received basic therapy without addition of ranolazine. Results. Analysis of clinical trials (CARISA, MARISA, ERICA, TERISA, MERLIN-TIMI, RIVER-PCI, RIMINI-TRIAL) proved the effectiveness of ranolazine as an antianginal and anti-ischemic drugs. The use of own program «Smart ECG» demonstrates the positive effect of ranolazine on STEMI and requires further implementation.Conclusion. In the European Society of Cardiology guidelines of the management of stable angina pectoris, ranolazine is given a class IIa (level of evidence B) recommendation as a second-line treatment to reduce angina frequency and improve exercise tolerance in subjects who cannot tolerate, have contraindications to, or whose symptoms are not adequately controlled by β- adrenergic blockers, calcium channel blockers and long-acting nitrates. In subjects with baseline low heart rate and low blood pressure, ranolazine may be considered as a first-line drug to reduce angina frequency and improve exercise tolerance - class IIa (level of evidence C) recommendation. Own study, which partially reflects the global approach according to the analyzed clinical studies, demonstrates the positive effect of ranolazine for patients with STEMI - analogue scale EQ–VAS indicates a positive effect, positive influence on the markers of electrical myocardial instability: decreasing of the probability of cases of SDNN decrease, depression of QT and maybe increase of ratio of maximum velocity for differentiated T wave.