Heart Rhythm In Patients Research Articles

Association Between Serum Levels of Nicotinamide-Adenine Dinucleotide Phosphate Oxidase 2 and the Development of Atrial Fibrillation After Isolated Coronary Artery Bypass Grafting: A Prospective Pilot Study.

To investigate the levels of nicotinamide-adenine dinucleotide phosphate oxidase 2 (NOX2) in serum and pericardial drainage samples in the early stage after coronary artery bypass grafting (CABG) and determine whether NOX2 is predictive of postoperative atrial fibrillation (POAF). This prospective pilot study involved 152 adults without history of atrial fibrillation who underwent first-time elective isolated CABG. Serum and pericardial fluid samples were simultaneously obtained from patients at baseline and 4, 12, and 24h post operation. NOX2 levels were determined using enzyme-linked immunosorbent assays. The heart rhythm of patients was continuously monitored through a Holter monitor until discharge. Logistic regression and receiver-operating characteristic (ROC) curve analyses were performed, as appropriate. Fifty-one patients (33.6%) experienced in-hospital POAF. NOX2 concentration in serum and pericardial drainage samples was increased after surgery, reached its peak at 12h, and gradually declined thereafter toward the baseline levels by 24 h. At 12h, patients with POAF had higher levels of serum NOX2 than those without (3.96 ± 0.35 vs. 3.70 ± 0.75μg/mL, respectively, p = 0.004). There were no discernible differences in pericardial NOX2 between the 2 groups. Multivariate analysis revealed that serum NOX2 at 12 h post operation was the strongest independent predictor of POAF (odds ratio: 2.179, 95% confidence interval: 1.084-4.377). The area under the ROC curve of the POAF predictive model was 0.732 (95% confidence interval: 0.654-0.801). Serum NOX2 may be useful in the identification of POAF. Larger studies are warranted to substantiate these findings.

Omega-3 Fatty Acids and Heart Rhythm, Rate, and Variability in Atrial Fibrillation.

Background Previous randomized control trials showed mixed results concerning the effect of omega-3 fatty acids (n-3 FAs) on atrial fibrillation (AF). The associations of n-3 FA blood levels with heart rhythm in patients with established AF are unknown. The goal of this study was to assess the associations of total and individual n-3 FA blood levels with AF type (paroxysmal versus nonparoxysmal), heart rate (HR), and HR variability in patients with AF. Methods and Results Total n-3 FAs, eicosapentaenoic acid, docosahexaenoic acid, docosapentaenoic acid, and alpha-linolenic acid blood levels were determined in 1969 patients with known AF from the SWISS-AF (Swiss Atrial Fibrillation cohort). Individual and total n-3 FAs were correlated with type of AF, HR, and HR variability using standard logistic and linear regression, adjusted for potential confounders. Only a mild association with nonparoxysmal AF was found with total n-3 FA (odds ratio [OR], 0.97 [95% CI, 0.89-1.05]) and docosahexaenoic acid (OR, 0.93 [95% CI, 0.82-1.06]), whereas other individual n-3 FAs showed no association with nonparoxysmal AF. Higher total n-3 FAs (estimate 0.99 [95% CI, 0.98-1.00]) and higher docosahexaenoic acid (0.99 [95% CI, 0.97-1.00]) tended to be associated with slower HR in multivariate analysis. Docosapentaenoic acid was associated with a lower HR variability triangular index (0.94 [95% CI, 0.89-0.99]). Conclusions We found no strong evidence for an association of n-3 FA blood levels with AF type, but higher total n-3 FA levels and docosahexaenoic acid might correlate with lower HR, and docosapentaenoic acid with a lower HR variability triangular index.

Internet of things in health care: case of cardiovascular diseases in Congo Brazzaville

In this paper, we present the implementation of a system to prevent cases of cardiovascular disease by allowing patients to have optimal monitoring at a lower cost every day. To achieve this, a system containing a connected cardiogram was designed through telecommunications and digital technology. The results obtained are encouraging insofar as this system facilitates the permanent monitoring of the evolution of heart rhythm in patients. It also enables telemedicine for all doctors, physists and professors in Africa, as the number of specialists is very low. But broadband usage in Africa is about 46%; in Congo Brazzaville, for example, it is 5%, with internet costs very high compared to international offers and the Congolese minimum wage. This work is an important detail to take into account in the development of our work in order to reduce the costs of this digital surveillance as much as possible.

Prevalence of pathological arrhythmia in patients triaged to “cardiac arrhythmia” in the emergency department: a preliminary study

BackgroundSymptoms caused by cardiac arrhythmia are common problems that lead to presentation to the emergency department. However, the prevalence of pathological heart rhythm in patients triaged for cardiac arrhythmia in the emergency department remains up to now unknown.Methods and resultsIn this retrospective study, patients triaged for cardiac arrhythmia admitted to the interdisciplinary emergency department of the Ludwig-Maximilians University Hospital in Munich within 1 year were included. Subsequently, cardiac rhythm in the 12-lead electrocardiogram, clinical presentation, admission rate, and diagnosis at discharge was analyzed. A total of 558 out of 39,798 patients were triaged for cardiac arrhythmia. Of these 42.3% of patients showed a pathological heart rhythm on the initial electrocardiogram (66.9% atrial fibrillation, 16.5% atrial flutter, 16.5% others). About 80% presented in emergency severity index III (many resources are needed without critical vitals) conditions. Sixty-two percent of the pathological electrocardiogram group and 60% of the sinus rhythm group of patients were admitted to the hospital, and 34.7% with pathological electrocardiogram underwent invasive investigations (16.8% in the sinus rhythm group). In 43.4% of patients, the diagnosis of cardiac arrhythmia was already known from previous medical contacts.ConclusionA total of 1.8% of patients who presented to our interdisciplinary emergency department were triaged for cardiac arrhythmia. With 49.5%, the hospital admission rate was quite high but the patients presented to the emergency department in our cohort were rarely in critical condition. As a high percentage of our cohort had a history of cardiac arrhythmia, better outpatient management is needed for these patients to reduce emergency department visits and save resources.

Differences in Treating Patients with Palpitations at the Primary Healthcare Level Using Telemedical Device Savvy before and during the COVID-19 Pandemic.

Background: Palpitations are one of most common reasons why a patient visits a general practitioner (GP) and is referred to a cardiologist. Coronavirus disease 2019 (COVID-19) has been associated with new-onset arrhythmias, which are difficult to diagnose at the primary healthcare level during pandemic-related lockdown periods. Methods: A total of 151 patients with a complaint of heart rhythm disorder were included from before and during the COVID-19 pandemic, as well as after the start of vaccination, in this cohort retrospective study. We used a telemedical device—namely, a personal electrocardiographic (ECG) sensor called Savvy—to investigate heart rhythm in patients. The primary outcome of the study was to evaluate the number of actual heart rhythm disorder patients and any differences that infection with or vaccination for COVID-19 had on patients handled in a primary healthcare setting. Results: We found a heart rhythm disorder in 8.6% of patients before the COVID-19 pandemic and in 15.2–17.9% of patients during the COVID-19 pandemic, where the difference was statistically significant (p = 0.002). During the COVID-19 pandemic, we found a heart rhythm disorder in almost 50% of patients that had tested positive for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 virus) more than one month ago. After the vaccinations started, we also found a heart rhythm disorder in almost 50% of non-vaccinated patients. Conclusions: Using a telemedical approach or remote consultation is a useful method, at the primary healthcare level, for diagnosing and treating patients with palpitations during times of lockdown.

Features of endothelial function and autonomic regulation of heart rhytm in patients with vasospastic angina

BACKGROUND: The clinical features of vasospastic angina are well known, but pathogenesis remains a subject of discussion. Changes in the autonomic regulation of coronary artery tone and endothelial function that contribute to the development of vasospasm are not well understood. The data on the subject from the published studies are contradictory.
 AIM: To evaluate features of endothelial function and autonomic regulation of heart rhythm in patients with vasospastic angina.
 MATERIALS AND METHODS: The study included 16 patients with proven vasospastic angina. All the patients have been evaluated for the heart rate variability at rest and vegetative tests (deep breathing, and active standing tests). Endothelial function has been assessed in terms of reactive hyperemia index by peripheral arterial tonometry using an Endo-PAT 2000 device.
 RESULTS: The baseline of the total heart rate variability was borderline with the normal parameters SDNN 50 (32.5; 50) ms in the patients with vasospastic angina. There were 14 patients who have demonstrated an imbalance of the autonomic nervous system at rest, mainly due to an increase of parasympathetic influences. The appropriate reaction of the autonomic nervous system, characterized by an increase of vagal influences, has been determined in 13 patients in the deep-breathing test. A paradoxical reaction, characterized by an increase of vagal influences on the heart rhythm, has been registered in 13 patients in the active standing tests. Endothelial dysfunction has been observed in half of the studied patients. Furthermore, a combination of both pathophysiological mechanisms, i.e., endothelial and autonomic dysfunctions have been observed in all the patients with a reduced reactive hyperemia index.
 CONCLUSIONS: According to the results of our study, the parasympathetic influences of the autonomic nervous system on the heart rhythm were predominant in the patients with vasospastic angina, which is not typical for coronary heart disease. All the patients had autonomic or endothelial dysfunction. A combination of both pathophysiological mechanisms has been observed in half of the examined patients.

Clinical Characteristics and Complications in Patients Undergoing Permanent Pacemaker Implantation

Abstract Background: Pacemakers are electronic impulse generators that are implanted to restore a regular heart rhythm in patients with symptomatic bradycardia. A large body of epidemiological data on permanent pacemaker implantation (PPI) originates from developed countries with minimal data from developing regions, especially sub-Saharan Africa. This study aims to describe patient demographics, clinical indications, short-term and long-term complications in patients undergoing PPI at the Charlotte Maxeke Johannesburg Academic Hospital, which is a large urban public teaching hospital in Johannesburg, South Africa. Methods: We retrospectively reviewed in-patient and out-patient medical records of consecutive patients who underwent index PPI over ten years (January 2009 to November 2018). Results: The study cohort comprised of 565 patients, of which 325 (57.52%) were female. The median age at first PPI was 71.8 [interquartile range: 61.7–78.8] years. The indications for pacemaker implantation were atrioventricular (AV) block in 417 (73.81%) and sinus node dysfunction in 114 (20.18%). A total of 40 (7.08%) patients experienced PPI-related complications. Lead dislodgement was the most common complication occurring in 16 (3.05%) patients. Females were 3.8 times more likely to experience a complication [odds ratio (OR): 3.80; 95% CI: 1.40–10.32, P = 0.009]. Conclusion: In this study, AV block was the most common indication for PPI, and the complication rate was found to be 7.08%. Furthermore, the risk of developing a complication was significantly higher in females.

Variability of heart rhythm in patients with myocardial infarction with Q wave with standard therapy and nutritive support with organic selenium

Aim. Assessment if the interrelation of the levels of selenium, parameters of heart rate variability (HRV), biochemical and rheological characteristics of blood in patients with Q-myocardial infarction (Q-MI) taking standard medicinal therapy and dietary correction with organic selenium in different stages of the disease.
 Materials and Methods. An open comparative clinical study was conducted with involvement of 90 patients (the average age 58.31.4, of them 71 men and 19 women) diagnosed with acute coronary syndrome with elevation of Q-segment with outcome into Q-MI. The patients were divided to two comparable groups: control group that received standard therapy, and the main group that additionally received dietary product enriched with organic selenium. In acute, subacute and cicatrization stages, the dynamic series of RR intervals were recorded and mathematically analyzed on Varicard 2.51 complex, some biochemical parameters of blood, selenium status, rheological properties of blood were assessed.
 Results. In the stage of hospital treatment, reduction of the heart rate (from 68.81.7 to 64.01.3 beat/min; p0.05) was recorded in the main group. The initial level of SDNN in both groups was within the critical range (25.01.3 msec), and stress index (SI) several time exceeded the norm (1356.2390.6 conv.un.); by the end of the observation both parameters did not achieve normal values in both groups. The coefficient of variation (CV) stayed below normal values throughout the whole treatment period, although in the dynamics it showed some tendency to growth. The spectrum power of the curve enveloping the dynamic series of RR intervals (HF) almost twice increased in the control group (р0.05). Correlation analysis of the interrelation of biochemical parameters of blood, coagulogram and selenium of blood serum with different parameters of mathematical analysis of the heart rhythm revealed interrelations of different levels and direction.
 Conclusion. Use of dietary product rich in selenium having a positive effect on the trophotropic functions of an organism, in complex with standard therapy, reduces tension of adaptation mechanisms and enhances adaptation potential of an organism that improves the prognosis and reduces risks.

Variability of heart rhythm in patients with viral cirrhosis depending on types of portal blood flow

The paper analyzes the results of examinations of 24 patients with viral cirrhosis of classes B and C according to Child-Pugh criteria. The control group consisted of 16 healthy patients. Patients with viral cirrhosis were divided into 2 groups: 1 group consisted of 14 patients with pseudonormokinetic type of portal blood flow; Group 2-10 patients with hyperkinetic type of portal blood flow with predominant acceleration of the linear velocity in the portal vein. The average age of patients was 35.2 ± 7.4 years. Left ventricular myocardium mass and left ventricular myocardium mass index were determined in all the patients; the diameter and the maximum linear velocity in the main portal vein were measured using an Artida pro Toshiba apparatus, Japan. Heart rate variability was studied at rest and in active orfhostasis using the «Neuro-Soth)program, Ivanovo. it was found that in patients with liver cirrhosis the sympathetic effects of the autonomic nervous system predominated, which coincided with the literature data. It was also shown that in patients with the pseudonormokinetic type of portal blood flow these effects were more pronounced. The relationship between HRV indices and the formation of left ventricular hypertrophy in patients with pseudo-normokinetic type of portal blood flow was revealed.

Efecto agudo del consumo de yerba mate (Ilex paraguariensis) sobre el ritmo cardíaco en pacientes derivados para estudio Holter

The consumption of yerba mate (YM) (Ilex paraguariensis) is common in South America and is now used all over the world. It contains many bioactive substances that can be beneficial. There is also the opinion that it may have harmful effects on heart rhythm, but no studies have been found on this. The aim of this study was to evaluate the acute effect of YM on heart rhythm in patients referred for a Holter study. A before and after pseudo-experimental clinical study was conducted by performing a Holter on 50 habitual users of YM, and another one after 24 without YM consumption. The use of other products that could interfere was also controlled. The mean age of the subjects was 55±15 years, and 52% were women. At least one vascular risk factor was found in 78%, with 44% structural heart disease, and 90% taking cardiovascular medication. The heart rate (HR) with and without YM was similar. Only the minimum hourly HR was lower when taking YM (61±10 vs. 63±9, P=.021). There was no significant difference in the incidence of sustained or non-sustained arrhythmias, or in ventricular extrasystoles. The total number of supra-ventricular premature beats was higher without YM (952±3,538 vs. 1,294±5,201, P=.014) and also the maximum hourly (86±302 vs. 107±360, P=.032). There was no difference in HR variability. In cardiology patients, usual users of YM, habitual consumption was not associated with significant changes in HR or an increase in the incidence of arrhythmias. There was less ectopic supraventricular activity.

Совместная динамика синхронизации низкочастотных колебаний в вегетативной регуляции кровообращения и показателей вариабельности ритма сердца у пациентов после операций с искусственным кровообращением в раннем послеоперационном периоде

Совместная динамика синхронизации низкочастотных колебаний в вегетативной регуляции кровообращения и показателей вариабельности ритма сердца у пациентов после операций с искусственным кровообращением в раннем послеоперационном периоде

Influence of additional risk factors on the antihypertensive efficacy of eprosartan and telmisartan in patients with essential hypertension

Objective. The aim of this study is to determine the effect of additional risk factors on blood pressure parameters, cardiovascular remodeling and the state of vegetative balance of the heart rhythm in patients with stage II essential hypertension (EH) under treatment with eprosartan and telmisartan.Materials and methods. The study included 100 patients with stage II essential hypertension (EH), 1–2 degrees with a low and moderate risk of developing cardiovascular complications. The smoker's status was 30.0 %, hypercholesterolemia more than 5 mmol/l – 69.0 %, overweight and obesity – 82.0 % of patients with EH. By randomisation, half of the patients received eprosartan in a daily dose of 600 mg, the rest received telmisartan at a daily dose of 80 mg for 6 months. Before the start of treatment and after 6 months of therapy, all the patients were subjected to the evaluation of general physical examinations, calculation of body mass index, determination of serum TC level, ECG Holter monitoring with analysis of heart rate variability, ambulatory blood pressure monitoring, echocardiography and duplex pulsed wave dopplerography of extracranial and intracranial vessels. Two weeks before the study, the patients did not take any antihypertensive drugs. Results. In patients with EH with additional risk factors using of eprosartan for 6 months is accompanied by a significant decrease in office SBP by 30.0 %, DBP by 21.6 %, PBP by 41.4 % and avg. BP by 25.5 %, regression of myocardial hypertrophy and improvement of diastolic function of the left ventricle. Eprosartan demonstrated a high antihypertensive efficacy on the effect on SBP in patients with EH with the presence/absence of tobacco smoking. However, the effect of eprosartan on DBP was better in patients with EH who do not have the status of a smoker. All the patients with EH, regardless of the presence or absence of an elevated level of total cholesterol, reached the target level of SBP under the influence of eprosartan. The antihypertensive effect of eprosartan against SBP was independent of the presence/absence of obesity in patients with EH. Eprosartan resulted in a significant increase in the maximum linear velocity in the left internal carotid artery by 2.8 % and in the vertebrobasilar region by 24.3 %. The total power of the spectrum under the influence of treatment significantly increased by 14.3 %.Antihypertensive therapy with telmisartan within half a year causes a significant decrease in office SBP by 24.8 %, DBP by 20.0 %, PBP by 31.8 %, avg. BP by 22.2 % In patients with EH who have/do not have the status of smoker and in all 100 % of patients with normal and elevated total cholesterol telmisartan was equally effective in achieving the target level of SBP. Obesity or its absence also did not significantly affect the effectiveness of antihypertensive therapy with telmisartan in patients with EH. Telmisartan, like eprosartan, causes regression of left ventricular hypertrophy. Telmisartan has a positive effect on carotid blood flow and does not affect the blood flow of the vertebrobasilar region. There were no changes in the parameters of the vegetative balance under the influence of telmisartan.Conclusion. In patients with EH with additional factors of cardiovascular risk using both eprosartan and telmisartan for half a year is accompanied by a significant decrease in blood pressure, regression of myocardial hypertrophy and improvement of diastolic function of the left ventricle, improvement of blood flow in the carotid region. In contrast to telmisartan, eprosartan increases the total power of the heart rate variability spectrum and does not affect the level of total cholesterol. The influence of telmisartan on the blood flow in the vertebrobasilar region is absent. Smoking, obesity, hypercholesterolemia do not reduce the antihypertensive efficacy of telmisartan and eprosartan against SBP and DBP. However, eprosartan is less effective in reducing DBP in patients with EH who smoke.

Arrhythmia recurrence in patients following cardiac surgery with concomitant therapy of atrial fibrillation – Experience of our cardiac center

IntroductionSurgical treatment of atrial fibrillation (AF) is a common and time-proven treatment method for this type of arrhythmias both as a separate procedure and as a procedure related to cardiac surgery for another indication (concomitant procedure). Patients experience arrhythmia recurrence despite highly efficient surgical treatment. These arrhythmias are often resistant to pharmacological treatment (due to an extensive fibrous substrate); therefore, electroanatomical mapping accompanying catheter ablation is significantly more effective. The arrhythmogenic fibrous substrate is a result of both a primary cardiac disease (an underlying disease causing atrial dilation) and surgical intervention (incision, cannula insertion sites, MAZE lines with a renewed spread of electrical signal in these blocks). Method and patientsElectroanatomical mapping and ablation were performed in 92 patients with arrhythmia recurrence following concomitant surgical treatment for AF between January 2010 and November 2015. The Cox maze procedure was performed using a disposable cryoablation catheter. The heart rhythm in patients following radiofrequency ablation procedure was monitored in half-year intervals (24-h Holter ECG, 7-day loop recorder, in some patients also by means of implanted pacemakers or implantable loop recorders). The average left atrial size (PLAX) was 50mm, 59% of patients underwent mitral valve surgery, 54% of patients had tricuspid valve surgery, 16% were operated for congenital developmental disorders, in 17% of patients, repeated cardiac surgery was performed. The above-mentioned facts show that these are patients with an extensive arrhythmogenic substrate. ResultsThe Cox maze procedure resulted in an extensive fibrous arrhythmogenic substrate in the atrium (arrhythmia recurrence following the maze procedure is more often regular atrial tachycardias while AF is predominant among arrhythmias for which the maze procedure was indicated). All patients had a follow-up visit after 12 months, 80% of patients presented for a follow-up visit after 24 months. Early recurrence after ablation (within 3 months following the procedure) was found in 21% of patients. Early recurrence after ablation was statistically significantly related to arrhythmia recurrence within 12 months (p=0.003) and arrhythmia recurrence within 24 months (p=0.003). 73% of patients had no recurrent AF or atrial tachycardia (AT) after 12 months and 53% after 24 months. A total of 146 arrhythmias were ablated, i.e. 1/3 of patients had more than 1 arrhythmia. These were persistent AF found in 24% of patients, paroxysmal AF seen in 13% of patients and regular AT detected in 53% of patients. More than one half of regular AT originated in LA (as perimitral atrial flutter in most cases). Remaining arrhythmias originated from the right atrium (as typical atrial flutter in half of the cases). 57% of patients had a renewed spread of signal in the mitral isthmus (ablation of the coronary sinus was necessary in 1/3 of patients). No domination in the number of reconnections was found for any of the pulmonary veins. The finding of a significantly reduced signal amplitude in the entire LA was associated with a higher risk of acute ablation failure (p=0.001). Acute ablation failure was associated with a higher risk of arrhythmia recurrence after 12 months (p=0.07). There was a trend of a higher AT incidence originating from the RA in patients who underwent surgery for a congenital heart defect (p=0.06). The diagnosis of arterial hypertension was associated with a higher risk of arrhythmia recurrence (p=0.13). The finding of persistent AF on ECG (compared to other findings, i.e. paroxysmal AF and regular AT) before ablation did not increase the risk of recurrence after ablation. ConclusionIn patients after cardiac surgery, catheterization performed to treat arrhythmia recurrence is a effective method of subsequent treatment, despite an extensive arrhythmogenic substrate. A rather large number of AT cases originate from the right atrium, in particular in patients after surgery for congenital heart defects. Patients with a significantly reduced signal in the larger part of the atrium due to an extensive arrhythmogenic substrate present the most complicated cases.

Cardiovascular Catheter With an Expandable Origami Structure

Interventional catheter ablation treatment is a noninvasive approach for normalizing heart rhythm in patients with arrhythmia. Catheter ablation can be assisted with magnetic resonance imaging (MRI) to provide high-contrast images of the heart vasculature for diagnostic and intraprocedural purposes. Typical MRI images are captured using surface imaging coils that are external to the tissue being imaged. The image quality and the scanning time required for producing an image are directly correlated to the distance between the tissue being imaged and the imaging coil. The objective of this work is to minimize the spatial distance between the target tissue and the imaging coil by placing the imaging coil directly inside the heart using an expandable origami catheter structure. In this study, geometrical analysis is utilized to optimize the size and shape of the origami structure and MRI scans are taken to confirm the MRI compatibility of the structure. The origami expandable mechanism could also be applied to other medical device designs that require expandable structures.

Inappropriate bradycardia in Ebola virus disease.

As part of French assistance for the outbreak of Ebola virus disease in west Africa, a military treatment center for infected healthcare workers was deployed in Conakry, Guinea. Although some cases of bradycardia have been reported since the first Ebola outbreak, they have never been documented to our knowledge. We studied heart rhythm in patients with Ebola virus disease to analyze inappropriate bradycardia and discuss its mechanism. Nine patients who tested positive for Ebola were admitted in March 2015. Baseline clinical data were noted at admission and twice a day during follow-up, and laboratory analyses (with troponin testing) were performed. At admission, patients had no or moderate tachycardia (pulse=82±27 bpm). Among them, a 32-year-old midwife admitted on her fourth day of symptoms had marked bradycardia: 43 bpm. ECG showed sinus bradycardia with no conduction disturbances or repolarization anomalies; findings were similar for the three other patients with bradycardia (<60 bpm). During follow-up, her pulse gradually increased, as it did for the other three; all four recovered. Despite several factors likely to promote tachycardia, we observed no or only moderate tachycardia in all patients with Ebola. In our study, ECG recorded sinus rhythm, without significant node dysfunction or atrioventricular block. In the absence of any evidence of myocarditis, we discuss the possibility of a central nervous system cause, associated with encephalitis. We observed relative or marked bradycardia in our patients infected with Ebola. We hypothesize that its causal mechanism was encephalitis.

Sensorless cardiac phase detection for synchronized control of ventricular assist devices using nonlinear kernel regression model.

Recently, driving methods for synchronizing ventricular assist devices (VADs) with heart rhythm of patients suffering from severe heart failure have been receiving attention. Most of the conventional methods require implanting a sensor for measurement of a signal, such as electrocardiogram, to achieve synchronization. In general, implanting sensors into the cardiovascular system of the patients is undesirable in clinical situations. The objective of this study was to extract the heartbeat component without any additional sensors, and to synchronize the rotational speed of the VAD with this component. Although signals from the VAD such as the consumption current and the rotational speed are affected by heartbeat, these raw signals cannot be utilized directly in the heartbeat synchronization control methods because they are changed by not only the effect of heartbeat but also the change in the rotational speed itself. In this study, a nonlinear kernel regression model was adopted to estimate the instantaneous rotational speed from the raw signals. The heartbeat component was extracted by computing the estimation error of the model with parameters determined by using the signals when there was no effect of heartbeat. Validations were conducted on a mock circulatory system, and the heartbeat component was extracted well by the proposed method. Also, heartbeat synchronization control was achieved without any additional sensors in the test environment.

Uncoupling of cardiac and respiratory rhythm in atrial fibrillation.

Rearranged origin of heart rhythm in patients with atrial fibrillation (AF) influences the regulation of the heart and consequently the respiratory rhythm, and the bidirectional interaction of these rhythms not documented. Hence, we examined coupling of the RR interval and the respiration (Resp) signal by coherence, Granger causality and the cross-sample entropy method of time series analysis in patients with AF and a healthy control group. In healthy subjects, the influence of respiration on cardiac rhythm was found as increased coherence at the breathing frequency (BF) range, significantly stronger interaction and synchrony from Resp to RR than from RR to Resp. On the contrary, in patients with AF, coherence at BF diminished, there were no causal interactions between signals in both directions, which resulted in equally great asynchrony between them. In AF, the absence of full functionality of the sinoatrial node, as an integrator of neural cardiac control, resulted in diminished vagal modulation of heart periods and consequently impaired bidirectional cardio-respiratory interaction.

Варіабельність ритму серця у хворих з ішемічною хворобою серця: вплив епідуральної анестезії

У статті описано зміни варіабельності ритму серця під впливом епідуральної анестезії в пацієнтів з ішемічною хворобою серця і практично здорових осіб, які зазнали оперативних втручань із приводу пахових гриж. Виявлено особливості впливу бупівакаїну та ропівакаїну на динаміку змін спектральних і статистичних показників варіабельності ритму серця в періопераційний період, проаналізовано їх характер в активний і пасивний періоди спостереження.

THE SUCCESS OF HEART RATE VARIABILITY BIOFEEDBACK PARAMETERS IN PERSONS WITH DIFFERENT LEVELS OF BLOOD PRESSURE

The aim was to determine the nature of cardiovascular reactions during a single session of heart rate variability (HRV) biofeedback in order to increase vagal effects on heart rhythm in patients with different initial levels of blood pressure (BP). 33 people with normal blood pressure (group I), 20 people with uncorrected arterial hypertension (AH) grade 1-2 (group II) and 22 people with AH grade 1-2 taking antihypertensive drugs (group III) were observed. The parameters of heart rate variability (HRV), BP and pulse aximetry in the initial stage, during a single HRV biofeedback session and after this session in order to increase the total power of the HRV spectrum (each stage 5 min). In patients of group II low success of HRV biofeedback session, a high sympathetic reactivity and reduced oxygen blood saturation were determined. A reactivity of vagal mechanism is more pronounced in persons of group III than in those of group II. It is reflected in a significant increase in their total power of the HRV spectrum compared to the initial values and in uptrend saturation levels during the biofeedback session. The ability to HRV biofeedback in order to increase the total power of the HRV spectrum for standard short recording (5 min) can be seen as a test to determine the safety reserves of vagal autonomic cardiovascular regulation in persons with increased blood pressure.

To the issue of normalizing the heart rhythm in patients with mitral valve disease complicated by atrial fibrillation

Aim. To examine an opportunity of sinus rhythm recovery in patients with mitral valve disease and atrial fibrillation (AF) by the means of surgery and concomitant procedures. Methods. 180 patients with AF who underwent mitral valve surgery using cardiopulmonary bypass in 2007-2011 were examined. Patients’ mean age was 52.5±0.5 years, 71 (39.4%) were male, 109 (60.6%) - female. Patients were divided into 3 groups: 22 patients with paroxysmal AF were included in Group I. 109 patients with persistent AF who underwent mitral valve surgery only were allocated to the Group II. 49 patients with persistent AF who underwent additional pulmonary vein isolation (radiofrequency ablation) were included in the Group III. Results. 83 (46.1%) of patients had single mitral valve disease, 62 (34.4%) of patients had multiple valve disease with involvement of tricuspid valve, 21 (11.7%) of patients had multiple valve disease with involvement of aortic valve, 21 (11.7%) of patients had all abovementioned valves involved. Mean arrhythmia duration was 36.3±3.8 months. Sinus rhythm was restored during the surgery in 16 (72.7%) patients of the Group I, in 60 (55.0%) patients of the Group II, in 41 (83.7%) patients of the Group III. Sinus rhythm was still registered at the discharge in 14 (63.6%), 19 (17.4%) and 13 (26.5%) respectively. Conclusion. It is possible to recover and hold regular rhythm in early postoperative period in more than 60% of cases in patients who underwent surgery for mitral valve disease and concomitant paroxysmal AF. Simultaneous radiofrequency ablation performed in patients with persistent AF increases sinus rhythm recovery rate in first day after surgery.