Electrocardiographic Methods Research Articles

The Clinical Relevance of ECG Parameters in the Prediction of Cardiac Mortality: A Comprehensive Review

About half of all heart disease deaths are caused by cardiac arrest, making it one of the major causes of mortality in prosperous countries. When confronted with potentially fatal arrhythmias, implanted preventive cardioverter defibrillators significantly improve survival chances. However, this is only possible if high-risk patients who are prone to spontaneous cardiac arrest are identified beforehand. The current analysis examines the most recent findings regarding the use of surface electrocardiogram (ECG) data to predict sudden cardiac arrest. Here, we provide a comprehensive overview of the literature on non-invasive ECG techniques for predicting these kinds of cardiovascular crises. Several electrocardiographic risk stratification methods, including T-wave alternans, signal-averaged ECG, T-peak-to-end variation, early repolarization, an extension of the QT interval, QRS duration, QRS cluster patterns, and Holter monitoring, have been reviewed and analysed. These ECG results have shown to be useful as first screening instruments. Nonetheless, no single ECG measure has shown to be an effective technique for classifying individuals based on their risk of sudden cardiac arrest to date. Nevertheless, one or more of these prospective SEM metrics might potentially be important in intricate risk categorization schemes.

Electrocardiographic approach strategies in patients with Parkinson disease treated with deep brain stimulation.

Deep brain stimulation (DBS) is an interdisciplinary and reversible therapy that uses high-frequency electrical stimulation to correct aberrant neural pathways in motor and cognitive neurological disorders. However, the high frequency of the waves used in DBS can interfere with electrical recording devices (e.g., electrocardiogram, electroencephalogram, cardiac monitor), creating artifacts that hinder their interpretation. The compatibility of DBS with these devices varies and depends on factors such as the underlying disease and the configuration of the neurostimulator. In emergencies where obtaining an electrocardiogram is crucial, the need for more consensus on reducing electrical artifacts in patients with DBS becomes a significant challenge. Various strategies have been proposed to attenuate the artifact generated by DBS, such as changing the DBS configuration from monopolar to bipolar, temporarily deactivating DBS during electrocardiographic recording, applying frequency filters both lower and higher than those used by DBS, and using non-standard leads. However, the inexperience of medical personnel, variability in DBS models, or the lack of a controller at the time of approach limit the application of these strategies. Current evidence on their reproducibility and efficacy is limited. Due to the growing elderly population and the rising utilization of DBS, it is imperative to create electrocardiographic methods that are easily accessible and reproducible for general physicians and emergency services.

Ventricular Arrhythmias in Left Ventricular Assist Device Patients-Current Diagnostic and Therapeutic Considerations.

Left ventricular assist devices (LVAD) are used in the treatment of advanced left ventricular heart failure. LVAD can serve as a bridge to orthotopic heart transplantation or as a destination therapy in cases where orthotopic heart transplantation is contraindicated. Ventricular arrhythmias are frequently observed in patients with LVAD. This problem is further compounded as a result of diagnostic difficulties arising from presently available electrocardiographic methods. Due to artifacts from LVAD-generated electromagnetic fields, it can be challenging to assess the origin of arrhythmias in standard ECG tracings. In this article, we will review and discuss common mechanisms, diagnostics methods, and therapeutic strategies for ventricular arrhythmia treatment, as well as numerous problems we face in LVAD implant patients.

Electrocardiographic, biochemical, and scintigraphic evidence for the cardioprotective effect of paricalcitol and vitamin D3 on doxorubicin-induced acute cardiotoxicity in rats.

We aimed to investigate the possible cardioprotective effects of paricalcitol (PR), its vitamin Dreceptor agonist, and vitamin D3 (VIT-D3) on an experimental model of doxorubicin (DX) cardiotoxicity by 99mTc-PYP scintigraphy, electrocardiographic (ECG) and biochemical methods. Forty-two male Wistar/Albino rats (250‒300 g; aged 10‒12 weeks) were randomly separated into six groups, namely into control (CN), doxorubicin (DX), paricalcitol (PR), vitamin D3 (VIT-D3), paricalcitol + doxorubicin (PR+DX), and vitamin D3 + doxorubicin (VIT-D3+DX) groups. Cardiotoxicity was induced by three doses of DX (18 mg/kg, i.p.) at 24-hour intervals on days 18, 19 and 20. PR (0.5 ug/ kg, i.p) and VIT-D3 (5,000IU/kg, i.p) were injected for 20 days before and after the application of DX (18 mg/kg, i.p.). On day 21 of the experiment, biochemical parameters [tumor necrosis factor TNF-alpha (TNF-α); interleukin-6 (IL-6), nitric oxide (NO), and cardiac troponin T(cTnT)], as well as ECG and scintigraphic (99mTc-PYP) features were assessed. Compared to CN, DX significantly raised TNF-α, IL-6, and NO in heart tissue, cTnT in serum, 99mTc-PYP uptake in the myocardium, and ECG parameters, specifically QRS complex duration, QT interval duration, and ST-segment amplitude, while also reducing heart rate (p<0.001). Pretreatment with PR and VIT-D3 mitigated these abnormalities produced by DX in the heart (p<0.001). Results show that vitamin Dreceptor agonist paricalcitol and vitamin Dprotect against DX-induced cardiotoxicity through anti-inflammatory and antioxidant effects (Fig. 4, Ref. 59). Text in PDF www.elis.sk Keywords: paricalcitol, doxorubicin, vitamin D, ECG, 99mTc-PYP scintigraphy, cardiotoxicity, inflammation.

Clinical magnetocardiography: the unshielded bet-past, present, and future.

Magnetocardiography (MCG), which is nowadays 60 years old, has not yet been fully accepted as a clinical tool. Nevertheless, a large body of research and several clinical trials have demonstrated its reliability in providing additional diagnostic electrophysiological information if compared with conventional non-invasive electrocardiographic methods. Since the beginning, one major objective difficulty has been the need to clean the weak cardiac magnetic signals from the much higher environmental noise, especially that of urban and hospital environments. The obvious solution to record the magnetocardiogram in highly performant magnetically shielded rooms has provided the ideal setup for decades of research demonstrating the diagnostic potential of this technology. However, only a few clinical institutions have had the resources to install and run routinely such highly expensive and technically demanding systems. Therefore, increasing attempts have been made to develop cheaper alternatives to improve the magnetic signal-to-noise ratio allowing MCG in unshielded hospital environments. In this article, the most relevant milestones in the MCG's journey are reviewed, addressing the possible reasons beyond the currently long-lasting difficulty to reach a clinical breakthrough and leveraging the authors' personal experience since the early 1980s attempting to finally bring MCG to the patient's bedside for many years thus far. Their nearly four decades of foundational experimental and clinical research between shielded and unshielded solutions are summarized and referenced, following the original vision that MCG had to be intended as an unrivaled method for contactless assessment of the cardiac electrophysiology and as an advanced method for non-invasive electroanatomical imaging, through multimodal integration with other non-fluoroscopic imaging techniques. Whereas all the above accounts for the past, with the available innovative sensors and more affordable active shielding technologies, the present demonstrates that several novel systems have been developed and tested in multicenter clinical trials adopting both shielded and unshielded MCG built-in hospital environments. The future of MCG will mostly be dependent on the results from the ongoing progress in novel sensor technology, which is relatively soon foreseen to provide multiple alternatives for the construction of more compact, affordable, portable, and even wearable devices for unshielded MCG inside hospital environments and perhaps also for ambulatory patients.

Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration

BackgroundEarly coronary occlusion detection by portable personal device with limited number of electrocardiographic (ECG) leads might shorten symptom-to-balloon time in acute coronary syndromes. ObjectivesThe purpose of this study was to compare the accuracy of coronary occlusion detection using vectorcardgiographic analysis of a near-orthogonal 3-lead ECG configuration suitable for credit card-size personal device integration with automated and human 12 lead ECG interpretation. MethodsThe 12-lead ECGs with 3 additional leads (“abc”) using 2 arm and 2 left parasternal electrodes were recorded in 66 patients undergoing percutaneous coronary intervention prior to (“baseline”, n = 66), immediately before (“preinflation”, n = 66), and after 90-second balloon coronary occlusion (“inflation”, n = 120). Performance of computer-measured ST-segment shift on vectorcardgiographic loops constructed from “abc” and 12 leads, standard 12-lead ECG, and consensus human interpretation in coronary occlusion detection were compared in “comparative” and “spot” modes (with/without reference to “baseline”) using areas under ROC curves (AUC), reliability, and sensitivity/specificity analysis. ResultsComparative “abc”-derived ST-segment shift was similar to two 12-lead methods (vector/traditional) in detecting balloon coronary occlusion (AUC = 0.95, 0.96, and 0.97, respectively, P = NS). Spot “abc” and 12-lead measurements (AUC = 0.72, 0.77, 0.68, respectively, P = NS) demonstrated poorer performance (P < 0.01 vs comparative measurements). Reliability analysis demonstrated comparative automated measurements in “good” agreement with reference (preinflation/inflation), while comparative human interpretation was in “moderate” range. Spot automated and human reading showed “poor” agreement. ConclusionsVectorcardiographic ST-segment analysis using baseline comparison of 3-lead ECG system suitable for credit card-size personal device integration is similar to established 12-lead ECG methods in detecting balloon coronary occlusion.

Wireless Single-Lead versus Standard 12-Lead ECG, for ST-Segment Deviation during Adenosine Cardiac Stress Scintigraphy.

Wearable wireless electrocardiographic (ECG) monitoring is well-proven for arrythmia detection, but ischemia detection accuracy is not well-described. We aimed to assess the agreement of ST-segment deviation from single- versus 12-lead ECG and their accuracy for the detection of reversible ischemia. Bias and limits of agreement (LoA) were calculated between maximum deviations in ST segments from single- and 12-lead ECG during 82Rb PET-myocardial cardiac stress scintigraphy. Sensitivity and specificity for reversible anterior-lateral myocardial ischemia detection were assessed for both ECG methods, using perfusion imaging results as a reference. Out of 110 patients included, 93 were analyzed. The maximum difference between single- and 12-lead ECG was seen in II (-0.019 mV). The widest LoA was seen in V5, with an upper LoA of 0.145 mV (0.118 to 0.172) and a lower LoA of -0.155 mV (-0.182 to -0.128). Ischemia was seen in 24 patients. Single-lead and 12-lead ECG both had poor accuracy for the detection of reversible anterolateral ischemia during the test: single-lead ECG had a sensitivity of 8.3% (1.0-27.0%) and specificity of 89.9% (80.2-95.8%), and 12-lead ECG a sensitivity of 12.5% (3.0-34.4%) and a specificity of 91.3% (82.0-96.7%). In conclusion, agreement was within predefined acceptable criteria for ST deviations, and both methods had high specificity but poor sensitivity for the detection of anterolateral reversible ischemia. Additional studies must confirm these results and their clinical relevance, especially in the light of the poor sensitivity for detecting reversible anterolateral cardiac ischemia.

A Longer Tpeak-Tend Interval Is Associated with a Higher Risk of Death: A Meta-Analysis.

A noninvasive tool for cardiovascular risk stratification has not yet been established in the clinical routine analysis. Previous studies suggest a prolonged Tpeak-Tend interval (the interval from the peak to the end of the T-wave) to be predictive of death. This meta-analysis was designed to systematically evaluate the association of the Tpeak-Tend interval with mortality outcomes. Medline (via PubMed), Embase and the Cochrane Library were searched from 1 January 2008 to 21 July 2020 for articles reporting the ascertainment of the Tpeak-Tend interval and observation of all-cause-mortality. The search yielded 1920 citations, of which 133 full-texts were retrieved and 29 observational studies involving 23,114 patients met the final criteria. All-cause deaths had longer Tpeak-Tend intervals compared to survivors by a standardized mean difference of 0.41 (95% CI 0.23-0.58) and patients with a long Tpeak-Tend interval had a higher risk of all-cause death compared to patients with a short Tpeak-Tend interval by an overall odds ratio of 2.33 (95% CI 1.57-3.45). Heart rate correction, electrocardiographic (ECG) measurement methods and the selection of ECG leads were major sources of heterogeneity. Subgroup analyses revealed that heart rate correction did not affect the association of the Tpeak-Tend interval with mortality outcomes, whereas this finding was not evident in all measurement methods. The Tpeak-Tend interval was found to be significantly associated with all-cause mortality. Further studies are warranted to confirm the prognostic value of the Tpeak-Tend interval.

High risk of ventricular repolarization abnormalities among hemodialytic end-stage renal disease patients.

Patients with chronic renal disease (CKD) are at a significantly elevated risk for ventricular arrhythmia. Several electrocardiographic (ECG) methods can be used to assess the ventricular arrhythmia risk on the standard 12-lead ECG.

Midterm postoperative outcomes of different types of surgical reconstruction of sinus venosus atrial septal defects with anomalous pulmonary venous connection: The Results of Prospective Cohort Study.

Sinus venosus atrial septal defects (SVASDs) constitute a substantial part of atrial septal defects and are usually characterized by anomalous pulmonary venous connection (APVC), causing complications like sinus node dysfunction and arrhythmias. Several surgical approaches are used for treating SVASDs in pediatric patients, including single- and two-patch techniques. The study aimed to prospectively evaluate and compare the safety and efficacy of these two methods with different follow-up periods. Ten patients aged 1-8 years with SVASDs and partial APVC were enrolled in the study at Bhanubhai and Madhuben Patel Cardiac Centre, Karamsad, India, between December 2018 and October2021. The single-patch (sandwich-patch) technique was used in two patients, whereas the two-patch (dual-patch) technique with autologous pericardium was used in seven. Safety was assessed as the absence of complications in the follow-up periods of 6 months, 1, and 2 years, whereas efficacy was estimated by the preserved sinus rhythm and the development of arrhythmias. Electrocardiographic and echocardiographic methods were used to evaluate both parameters. No deaths, reoperations, pulmonary vein, and superior vena cava (SVC) stenosis or phrenic nerve palsy were observed among the 10 patients in the three follow-up periods. Sinus rhythm was arrested in two of the seven patients who underwent two-patch repair, whereas no rhythm disturbances occurred in those who underwent single-patch repair. Both techniques used in SVASD repair with autologous pericardium proved to cause the smaller rate of complications in midterm postsurgical phase. However, there is a potentially great risk of the development of sinus node malfunction after the application of the two-patch technique. Therefore, methods avoiding sinus node interference are preferred in patients with partial APVC involving SVC.

New Electrocardiographic Methods Based on the Standard 12-Leads Ecg: Bipolar Precordial Leads

New Electrocardiographic Methods Based on the Standard 12-Leads Ecg: Bipolar Precordial Leads

OR46. Increased of Ventricular Repolarization Abnormalities in Hemodialytic End-Stage Renal Disease

Abstract Background and Aims Cardiac or ventricular arrhythmia risks, including sudden cardiac death, are highly increased in patients with CKD, especially when reaching end-stage renal disease (ESRD). Several electrocardiographic (ECG) methods can be used to assess ventricular arrhythmia risk on the standard 12-lead ECG. This study aimed to evaluate ventricular repolarization abnormalities in patients with hemodialytic ESRD. Methods and Results Fifty-three patients with hemodialytic ESRD and thirty-two pre-dialytic CKD as controls were enrolled in the study. ECG parameters: QT, QTc, Tp-e, Tp-e/QT, and Tp-e/QTc were measured manually using callipers on ECG recordings from all participants. The normality of the data was analyzed with the Shapiro-Wilk test. The independent-samples T-test for normal distribution and the Mann-Whitney U test for abnormal distribution were used for analysis. Mean age in hemodialytic and pre-dialytic groups were 46.6±11.5 and 56.1±10.6 years old, respectively. Mean creatinine serum in hemodialytic and pre-dialytic groups were 9.9±4.7 and 2.4±0.7 mg/dL. Ventricular repolarization abnormalities in hemodialytic compared to pre-dialytic group: QTc (448.2±33.9 vs. 427.9±31.3 msec, p = 0.007), Tp-e (80[40:130] vs. 70[40:120] msec, p = 0.022), Tp-e/QT (0.23±0.06 vs. 0.20±0.05, p = 0.043) were found to be significantly different. While QT (360.4±47.8 vs. 355.9±36.6 msec, p = 0.646) and Tp-e/QTc (0.18[0.08:0.33] vs. 0.16[0.09:0.25], p = 0.196) were increased in hemodialytic group but not significantly different. Conclusion Ventricular repolarization abnormalities were found to be increased in patients with hemodialytic end-stage renal disease. Measuring ECG parameters of ventricular repolarization may help to identify risk for arrhythmogenesis and sudden cardiac death.

Some features of changes in the performance of the circulatory system and their relationship in qualified athletes in relationship

The evaluation of the peculiarities of changes in the indicators of the functioning of the cardiovascular system and their relationships in 53 qualified athletes at the stages of long- term training was carried out. The aim of the study was to identify changes in the functional state of the cardiovascular system and the peculiarities of their relationship in skilled athletes in connection with long training. Electrocardiographic and statistical methods were used. The ECG results of the study of athletes revealed signs of impaired automaticity, excitation, conductivity, mainly by the type of blockade of the right leg of the His bundle, contractility. Their frequency and severity increased due to the duration of training. Similar changes were found for a combination of changes. Of particular note is the detection of myocardial hypertrophy and bradycardia, the number of which and their combination also increases due to the duration of training. The results dictate the need to include mandatory echocardiography, and in the case of bradycardia - atropine tests, in the list of studies during medical monitoring

Electrocardiographic and imaging methods in risk stratification of sudden cardiac death in patients with chronic heart failure

Ventricular arrhythmias (in particular, episodes of ventricular fibrillation and paroxysmal ventricular tachycardia) are associated with a significant increase in the risk of sudden cardiac death (SCD) in patients with chronic heart failure (CHF). The most widely used strategy for stratification of SCD risk in patients with CHF uses low left ventricular ejection fraction as the main criterion, but modern epidemiological studies confirm the need to search for new SCD markers, in particular, electrocardiographic and imaging ones. The most reasonable and promising is an integrated approach that implies a combination of sequential use of non-invasive and invasive techniques, which makes it possible to improve the identification of high-risk individuals who need an invasive strategy to prevent SCD, but who do not always meet the “classical” criteria for ICD implantation.

A review of the literature on the accuracy, strengths, and limitations of visual, thoracic impedance, and electrocardiographic methods used to measure respiratory rate in hospitalized patients.

BackgroundRespiratory rate (RR) is one of the most important indicators of a patient's health. In critically ill patients, unrecognized changes in RR are associated with poorer outcomes. Visual assessment (VA), impedance pneumography (IP), and electrocardiographic‐derived respiration (EDR) are the three most commonly used methods to assess RR. While VA and IP are widely used in hospitals, the EDR method has not been validated for use in hospitalized patients. Additionally, little is known about their accuracy compared with one another. The purpose of this systematic review was to compare the accuracy, strengths, and limitations of VA of RR to two methods that use physiologic data, namely IP and EDR.MethodsA systematic review of the literature was undertaken using prespecified inclusion and exclusion criteria. Each of the studies was evaluated using standardized criteria.ResultsFull manuscripts for 23 studies were reviewed, and four studies were included in this review. Three studies compared VA to IP and one study compared VA to EDR. In terms of accuracy, when Bland–Altman analyses were performed, the upper and lower levels of agreement were extremely poor for both the VA and IP and VA and EDR comparisons.ConclusionGiven the paucity of research and the fact that no studies have compared all three methods, no definitive conclusions can be drawn about the accuracy of these three methods. The clinical importance of accurate assessment of RR warrants new research with rigorous designs to determine the accuracy, and clinically meaningful levels of agreement of these methods.

Predictive value of frontal QRS-T angle after cardiac resynchronization therapy

ObjectiveIt is practical and useful to detect patients who benefit from cardiac resynchronization therapy (CRT) by electrocardiographic (ECG) methods. In this study, the predictive role of the frontal QRS-T angle and other ECG parameters was evaluated in CRT responder patients. MethodSeventy-seven consecutive patients with left ventricular ejection fraction (LVEF) ≤ 35%, New York Heart Association (NYHA) classes II-III, ambulatory class IV and normal sinus rhythm, who had complete left bundle branch block and were treated with CRT were included in this study. Patients were classified as “CRT responders” and “CRT non responders” according to their LVEF improvement. The frontal QRS-T angle was calculated as the absolute value of the difference between the QRS and T wave axes [frontal QRS-T angle = (QRS axis-T axis)]. ResultsThe mean age of the patients was 64.5 ± 9.1 years, and the average follow-up was 28 (12–47) months. The post-implantation LVEF was higher in the patients CRT responders group (p < 0.001). Post–implantation frontal QRS-T angle (p = 0.003), QRS duration (p = 0.008) and cQT interval (p = 0.012) values were much shorter in the CRT responder group. Multivariable regression analyses showed that the frontal QRS-T angle and age were independent risk factors for CRT response (p = 0.009). The results of the receiver operating characteristic curve analyses (ROC) showed that the predictive optimal cut-off value of CRT response for the frontal QRS-T angle was <135 degrees (AUC: 0.69, 95% CI 0.575–0.814, p = 0.004). ConclusionThe narrowed frontal QRS-T angle (<135 degrees), QRS duration and cQT interval were associated with CRT response in heart failure patients. The frontal QRS-T angle can be an independent predictor of CRT response.

MO758DIAGNOSTIC ACCURACY OF ELECTROCARDIOGRAPHIC METHODS OF ESTIMATION OF LEFT VENTRICULAR HYPERTROPHY IN A HAEMODIALYSIS POPULATION

Abstract Background and Aims Left ventricular hypertrophy is common in end stage renal disease (ESRD) and haemodialysis. Its association with cardiovascular outcomes has been demonstrated. In this study we evaluated the diagnostic accuracy of electrocardiographic methods of calculating LVH compared to Real Time 3- Dimensional Echocardiogram (RT3DE) which we used as a surrogate gold standard test. Method This study was performed as a post-hoc analysis of a sub-group of patients enrolled into the Salford Kidney Study (SKS). Patients included into this analysis are from the sub-group of SKS previously known as the CRISIS-HD cohort. All adult haemodialysis patients at Salford Royal NHS Foundation Trust, UK or one of its satellite units are considered for inclusion. In this study we examined the sensitivity, specificity, positive predictive value and negative predictive value of Sokolow – Lyon and Romhilt –Estes methods in comparison to RT3DE. Results The final sample comprised 44 patients. The vast majority were Caucasian (39 patients). The mean age of the patients was 62 ± 13 years and mean time on dialysis 5.1 ± 2.9 years. The sensitivity of both ECG methods for diagnosis of LVH was very low. This was the case for the whole sample and also for individual groups. Romhilt – Estes was marginally better than Sokolow – Lyon and that was especially the case for male patients. Conclusion Our study shows that ECG methods for assessment of LVH that rely on voltage criteria have very low sensitivity and unreliable specificity compared to RT3DE and also conventional M –Mode echocardiography. As a result, they could not be reliably used as a quick and inexpensive method of LVH estimation in clinical practice in the case of haemodialysis patients.

Ischemic stroke in a patient with interatrial block: Is it only a coincidence or a clear relationship?

Atrial fibrillation (AF) can be detected in nearly 25% of all patients with stroke by sequentially combining different electrocardiographic methods. Prediction of early cardio-embolic stroke remain a permanent challenge in everyday practice. The early identification of an increased risk for atrial fibrillation episodes (which are frequently asymptomatic) is essential for the prevention of cardioembolic events. One of the noninvasive modalities of atrial fibrillation prediction is represented by the electrocardiographic P-wave analysis. This includes study and diagnosis of interatrial conduction block. Our short case report presents a case with ischemic cortico-sottocortical stroke involving capsulo and caudo regions in a woman patient with interatrial block as realized by electrocardiographic P analysis.

P931Assosiation of the levels of galectin-3 and MMP-1 with the type of myocardial dyssynchrony in patients with heart failure and concomitant type 2 diabetes mellitus

Abstract Background Myocardial dyssynchrony leads to heart remodeling and the progression of heart failure (HF) in patients with type 2 diabetes mellitus. Studying the mechanisms of the development of myocardial dyssynchrony can help in timely diagnosis and treatment. Aims To study the association of the level of galectin-3 and matrix metalloproteinase 1 (MMP-1) and the type of myocardial dyssynchrony in patients with heart failure and concomitant type 2 diabetes mellitus. Methods 98 patients with heart failure and concomitant type 2 diabetes mellitus were examined, average age (67.45 + 10.32) years. Patients were divided into two groups due to the presence or absence of myocardial dyssynchrony: the first group: with myocardial dyssynchrony (n = 56), the second group: patients without myocardial dyssynchrony ( n = 42). All patients were examined for electrical (enhanced QRS ≥ 120 ms) and mechanical myocardial dyssynchrony using echocardiographic and electrocardiographic methods for assessing intraventricular, interventricular, atrioventricular and combined myocardial dyssynchrony, as well as serum concentration of fibrosis markers - galectin-3 and MMP-1. The determination of percentage of interstitial collagen volume fraction (CVF) was performed in both groups. Results To determine the levels of fibrosis markers depending on the presence of diabetes, the results of patients with myocardial dyssynchrony (n = 56) were compared with the results of the control group without myocardial dyssynchrony (n = 42). In patients with myocardial dyssynchrony, there was an increase in the levels of galectin-3 (7.49 + 0.6 ng / ml) and CVF (7.6 ± 4.03%), a decrease in MMP-1 (0.46 + 0.2 ng / ml ) compared with the group without myocardial dyssynchrony (p &amp;lt;0.05). An increase in galectin-3 levels was observed in the presence of combined forms of myocardial dyssynchrony. In patients with a combination of intraventricular, interventricular, or atrioventricular myocardial dyssynchrony (n = 28), the levels of galectin-3 (9.03 + 0.3 ng / ml) and CVF (8.04 + 1.6%) were the highest; in patients with isolated forms of myocardial dyssynchrony, the levels of galectin-3 (6.67 + 0.2 ng / ml) and CVF (6,93 + 1,4%) were significantly lower. MMP-1 was greater in patients with isolated forms of myocardial dyssynchrony (0.78 + 0.2 ng / ml), compared with patients with combined forms of myocardial dyssynchrony (0.2 + 0.01 ng / ml) (p &amp;lt;0.05 ). Conclusions An association is observed between myocardial dyssynchrony and the levels of galectin-3 and MMP-1 in the blood. These findings are important for prognostic implications and require further research.

Variability Inter-observer between Three Methods of Electrocardiographic (Conventional, Computerized and Computerized Printed) on Healthy Cats

Background: Electrocardiography is an exam widely used in feline medicine. It consists of recording the electrical activity of the heart in waves representing myocardial depolarization and repolarization. Two electrocardiographic evaluation methods are employed in dogs and cats: computerized and conventional. However, possible differences in ECG results performed by the different methods have been reported. This paper aims to evaluate the observer's interference in the interpretation of the electrocardiographic exams and possible differences between the methods: conventional single channel, computerized screen and computerized printed of healthy cats.Materials, Methods &amp; Results: Electrocardiographic tracings were obtained from 58 healthy cats, aged between 1 and 10 years-old, of both sexes, of the Persian and mixed breed and therefore interpreted by four observers with similar degree of experience. The examinations were performed in a sequential manner, the computerized method first, and then the conventional method. The animals were gently contained in the right lateral decubitus position. The tracings obtained by the conventional method were printed on thermally sensitive graph paper. The computerized method was performed in computer by means of specific software (TEB® ECGPC version 6.2), being the waves delimited by the observer. The tracings were also printed by means of a jet printer, and also interpreted. The morphology of P waves, QRS complexes and T waves were analyzed in the derivations: I, II, III, aVR, aVL and aVF. Heart rate, amplitude and duration of the P, QRS and T waves, PR, QT and heart rate (HR) intervals were calculated in derivation II. Mean electric axis was determined in leads I and III. Comparing the methods, there was a difference observed in the values of P and R waves, QRS complex, QT and PR intervals and T wave polarity. The interpretation of the evaluators presented statistical differences in the duration of the P wave, QRS, QT and HR. The three methods used presented differences during the mean of the interpretation of the evaluators.Discussion: Some factors such as the positioning of the animal and the use of chemical containment may influence the electrocardiographic tracings, as well as variations between electrocardiographic devices. In our study, the non-use of sedation and the use of the same equipment in all animals reduced the variability of the results. The interpretation of the computerized method printed and on the screen presented different results which can be explained by the reduced human visual capacity when compared to the computers. It is known that the interpretation of different tracings by the observers might influence the results of the examination. The evaluators of the present study evaluated the same tracings, but there was a difference in the interpretation of the observers. Regarding the methods, there was a difference between the three methods evaluated in relation to the ST segment. The computerized on-screen method demonstrated in its totality isoelectric ST segments that represent normal pattern for the species. The conventional and computerized printed methods presented results of elevation in ST segments that represent alterations in the diagnosis. There was a difference between the measurements performed by different observers, however this fact did not influence the results of the tests, since the parameters remained within the normality standards for species. It can be concluded that the variation between observers and among the three methods evaluated suggests that the ST segment interpretation is subtle and less influenced when performed in the computerized method.