The role of electrocardiography in the elaboration of a new paradigm in cardiac resynchronization therapy for patients with nonspecific intraventricular conduction disturbance

Cardiac resynchronization therapy （CRT） is associated with a favorable outcome only in patients with left bundle branch block （LBBB） pattern and in patients with a QRS duration 〉 150 ms, in patients with non-LBBB pattern with a QRS duration of 120-150 ms usually is not beneficial. After adjusting for QRS duration, QRS morphology was no longer a determinant of the clinical response to CRT. In contrast to the mainstream view, we hypothesized that the unfavorable CRT outcome in patients with non-LBBB and a QRS duration of 120-150 ms is not due to the QRS morphology itself, but to less dyssynchrony and unfavorable patient characteristics in this subgroup, such as more ischemic etiology and greater prevalence of male patients compared with patients with LBBB pattern. Further, the current CRT technique is devised to eliminate the dyssynchrony present in patients with LBBB pattern and inappropriate to eliminate the dyssynchrony in patients with non-LBBB pattern. We also hypothesized that electrocardiography may also provide information about the presence of interventricular and left intraventricular dyssynchrony and the approximate location of the latest activated left ventricular （LV） region. To this end, we devised new ECG criteria to estimate interventricular and LV intraventricular dyssynchrony and the approximate location of the latest activated LV region. Our preliminary data demonstrated that the latest activated LV region in patients with nonspecific intraventricular conduction disturbance （NICD） pattern might be at a remote site from that present in patients with LBBB pattern, which might necessitate the invention of a novel CRT technique for patients with NICD pattern. The application of the new interventricular and LV intraventricular dyssynchrony ECG criteria and a potential novel CRT technique might decrease the currently high nonresponder rate in patients with NICD pattern.

Bipolar Esophageal Electrocardiography by Using Standard Limb Leads

The ear-xiphisternum distance (EXD, the distance from the low edge of the ear to the xiphisternal basis in supine position) was used as a reference value for esophageal catheter insertion. ECGs recorded in the esophagus with bipolar electrocardiography using standard limb lead (ESLL) and conventional unipolar lead (ECUL) were compared. 112 patients with sinus rhythm and 76 patients during paroxysmal supraventricular tachycardia (PSVT) whose P-wave and QRS complex did not overlap were studied. The results suggested that in sinus rhythm the amplitude of the P-wave in ESLL was larger and the T-wave was smaller than in ECUL. During PSVT, the P-wave was much clear and higher in each lead of ESLL than that in ECUL. The ideal range of esophageal ECG recording was situated between the end of EXD and 6. 5 cm proximal to it.

Antenatal Noninvasive Fetal Electrocardiography:A Literature Review

Fetal heart rate(FHR)monitoring is one of the central parts of obstetric care.Ultrasound-based technologies such as cardiotocography(CTG)remain the most common method for FHR monitoring.The CTG’s limitations,including subjective interpretation,high interobserver variability,and the need for skilled professionals,led to the development of computerized CTG(cCTG).While cCTG demonstrated advantages,its superiority over visual interpretation remains inconclusive.This has prompted the exploration of alternatives like noninvasive fetal electrocardiography(NIFECG).This review explores the landscape of antenatal FHR monitoring and the need for remote FHR monitoring in a patient-centered care model.Additionally,FHR monitoring needs to evolve from the traditional approach to incorporate artificial intelligence and machine learning.The review underscores the importance of aligning fetal monitoring with modern healthcare,leveraging artificial intelligence algorithms for accurate assessments,and enhancing patient engagement.The physiology of FHR variability(FHRV)is explained emphasizing its significance in assessing fetal well-being.Other measures of FHRV and their relevance are described.It delves into the promising realm of NIFECG,detailing its history and recent technological advancements.The potential advantages of NIFECG are objective FHR assessment,beat-to-beat variability,patient comfort,remote prolonged use,and less signal loss with increased maternal body mass index.Despite its promise,challenges such as signal loss must be addressed.The clinical application of NIFECG,its correlation with cCTG measures,and ongoing technological advancements are discussed.In conclusion,this review explores the evolution of antenatal FHR monitoring,emphasizing the potential of NIFECG in providing reliable,home-based monitoring solutions.Future research directions are outlined,urging longitudinal studies and evidence generation to establish NIFECG’s role in enhancing fetal well-being assessments during pregnancy.

Optimization of atrioventricular delay by surface electrocardiography during dual chamber pacing

Background Nominal atrioventricular （AV） interval in dual chamber pacemaker （DDD） is not the best AV delay in the majority of patients with atrioventricular block. To find a simple method for optimizing AV delay adjustment, we assessed surface electrocardiography （ECG） for optimizing AV delay during dual chamber pacing. Methods DDD pacemakers were implanted in 46 patients with complete, or almost complete, AV block. Optimal AV delay was achieved by programming an additional delay of 100 ms, to the width of intrinsic P wave or to the interval between pacing spike to the end of P wave on surface ECG. Leit ventricular （LV） end diastolic and end systolic volumes, ejection fraction and diastolic parameters were measured by Doppler echocardiography during both nominal and optimal AV delay pacing.Results Compared to nominal AV delay setting, LV end diastolic volume increased [to （53.2±11.3） ml from （50.2 ± 10.2） ml, P〈0.05], end systolic volume decreased [to （26.1 ± 9.0） ml from （27.9 ± 8.2） ml, P〈0.05] during adjusted AV delay pacing, resulting in an increase in LV ejection fraction [to （68.2±5.3）% from （64.5±4.3）%, P〈0.05]. LV diastolic filling and isovolumic relaxation time were not significantly changed.Conclusion Optimization of AV delay by surface ECG is a simple method to improve LV systolic function during dual chamber pacing.

Contribution of Quick Sequential Organ Failure Assessment Score Combined with Electrocardiography in Risk Stratification of Patients with Acute Pulmonary Embolism

Background： The quick Sequential Organ Failure Assessment （qSOFA） score emerged recently. We investigated its contribution to risk stratification in acute pulmonary embolism （PE） by combining with electrocardiography （ECG）. Methods： Acute PE patients diagnosed in Beijing Chao-Yang Hospital, Capital Medical University, from 2008 to 2018 were retrospectively studied and divided into high- and low-risk groups by imaging and biomarkers. The ECG scores consisted oftachycardia, McGinn-White sign （S1Q3T3）, right bundle branch block, and T-wave inversion of leads V1-V3. A new combination of qSOFA scores and ECG scores by logistic regression for predicting high-risk stratification patients with acute PE was evaluated by a receiver operating characteristic curve. Results： Totally 1318 patients were enrolled, including 271 in the high-risk group and 1047 in the low-risk group. A combination predictive scoring system named qSOFA-ECG = qSOFA score ＋ ECG score was created. The optimal cutoffvalue for qSOFA-ECG was 2, and the sensitivity, specificity, positive predictive value, and negative predictive value were 81.5%, 72.3%, 43.2%, and 93.8%, respectively. For predicting high-risk stratification and reperfusion therapy, the qSOFA-ECG is superior to PE Severity Index （PESI） and simplified PESI. Conclusions： The qSOFA score contributes to identify acute PE patients with potentially hemodynamic decompensation that need monitoring and possible reperfusion therapy at the emergency department arrival when used in combination with ECG score.

Radial Pulse and Electrocardiography Modulation by Mild Thermal Stresses Applied to Feet: An Exploratory Study with Randomized, Crossover Design

Objective:To investigate the changes in radial pulse induced by thermal stresses(TSs).Methods:Sixty subjects were enrolled.Using an open-label,2x2 crossover randomization design,both feet of each subject were immersed in 15%:water for cold stress(CS)and in 40 X:water for heat stress(HS)for 5 min each.Radial pulse,respiration and electrocardiogram(ECG)signals were recorded before,during and immediately after the TSs.Results:The an alysis of heart rate variability revealed that CS in creased the low-freque ncy(LF)and high-frequency(HF)components(P<0.05)and that HS reduced the LF and HF components(P<0.01).Both TSs reduced the normalized LF,increased the normalized HF,and reduced the LF/HF ratio.The differences in the ECG signals were more dominant during the TS sessions,but those in the radial pulse signals became more domi nant immediately after the TS sessi ons.CS decreased the pulse depth(P<0.01)and in creased the radial augme ntation in dex(P<0.1),and HS in creased the pulse pressure(P<0.1)and sube ndocardial viability ratio(P<0.01).There were no significant differences in pulse rate during the three time sequences of each TS.The respiration rate was increased(P<0.1),and the pulse rate per respiration(P/R ratio)was significantly decreased(P<0.05)with CS.The HF region(10-30 Hz)of the pulse spectral density was suppressed during both TSs.Conclusions:CS induced vasoconstriction and sympathetic reactions,and HS induced vasodilation and parasympathetic reacti ons.Based on defi nitions used in pulse diag no sis,we made the novel discoveries that the pulse became slower(decreased P/R ratio),more floating and tenser under CS and that the HF region of the spectral power decreased significantly under both TSs.

Research on the driver fatigue early warning model of electric vehicles based on the fusion of EMG and ECG signals

Electric vehicles have been rapidly developing worldwide due to the use of new energy.However,at the same time,serious traffic accidents caused by driver fatigue in emergency situations have also drawn widespread attention.The lack of datasets in real vehicle test environments has always been a bottleneck in the research of driver fatigue in electric vehicles.Therefore,this study establishes a dataset from real vehicle test,applies the Bayesian optimization support vector machine(BOA-SVM)algorithm to take features of electromyography(EMG)and electrocardiography(ECG)signals as input and develop an early warning model for driving fatigue detection.Firstly,the driver’s EMG and ECG signals are collected through real vehicle testing experiments and then combined with the driver’s subjective fatigue evaluation scores to establish the dataset.Secondly,the study establishes a driver fatigue early warning model for emergency situations.Time-domain and frequency-domain features are extracted from the EMG signals.Principal component analysis(PCA)is applied for dimensionality reduction of these features.The experimental results show that based on the input of dimensionality reduced EMG features and ECG features,the BOA-SVM algorithm achieved an accuracy of 94.4%in classification.

SVEAT score outperforms HEART score in patients admitted to a chest pain observation unit

BACKGROUND Timely and accurate identification of subgroup at risk for major adverse cardiovascular events among patients presenting with acute chest pain remains a challenge.Currently available risk stratification scores are suboptimal.Recently,a new scoring system called the Symptoms,history of Vascular disease,Electrocardiography,Age,and Troponin(SVEAT)score has been shown to outperform the History,Electrocardiography,Age,Risk factors and Troponin(HEART)score,one of the most used risk scores in the United States.AIM To assess the potential usefulness of the SVEAT score as a risk stratification tool by comparing its performance to HEART score in chest pain patients with low suspicion for acute coronary syndrome and admitted for overnight observation.METHODS We retrospectively reviewed medical records of 330 consecutive patients admitted to our clinical decision unit for acute chest pain between January 1st to April 17th,2019.To avoid potential biases,investigators assigned to calculate the SVEAT,and HEART scores were blinded to the results of 30-d combined endpoint of death,acute myocardial infarction or confirmed coronary artery disease requiring revascularization or medical therapy[30-d major adverse cardiovascular event(MACE)].An area under receiving-operator characteristic curve(AUC)for each score was then calculated.C-statistic and logistic model were used to compare RESULTS A 30-d MACE was observed in 11 patients(3.33%of the subjects).The AUC of SVEAT score(0.8876,95%CI:0.82-0.96)was significantly higher than the AUC of HEART score(0.7962,95%CI:0.71-0.88),P=0.03.Using logistic model,SVEAT score with cut-off of 4 or less significantly predicts 30-d MACE(odd ratio 1.52,95%CI:1.19-1.95,P=0.001)but not the HEART score(odd ratio 1.29,95%CI:0.78-2.14,P=0.32).CONCLUSION The SVEAT score is superior to the HEART score as a risk stratification tool for acute chest pain in low to intermediate risk patients.

Significance of lead aVR in acute coronary syndrome

The 12-lead electrocardiogram(ECG)is a crucial tool in the diagnosis and risk stratification of acute coronary syndrome(ACS).Unlike other 11 leads,lead aVR has been long neglected until recent years.However,recent investigations have shown that an analysis of ST-segment shift in lead aVR provides useful information on the coronary angiographic anatomy and risk stratification in ACS.ST-segment elevation in lead aVR can be caused by(1)transmural ischemia in the basal part of the interventricular septum caused by impaired coronary blood flow of the first major branch originating from the left anterior descending coronary artery;(2)transmural ischemia in the right ventricular outflow tract caused by impaired coronary blood flow of the large conal branch originating from the right coronary artery;and(3)reciprocal changes opposite to ischemic or non-ischemic ST-segment depression in the lateral limb and precordial leads.On the other hand,ST-segment depression in lead aVR can be caused by transmural ischemia in the inferolateral and apical regions.It has been recently shown that an analysis of T wave in lead aVR also provides useful prognostic information in the general population and patients with prior myocardial infarction.Cardiologists should pay more attention to the tracing of lead aVR when interpreting the12-lead ECG in clinical practice.

Cardiac involvement in Duchenne and Becker muscular dystrophy

Duchenne and Becker muscular dystrophy(DMD/BMD) are X-linked muscular diseases responsible for over 80% of all muscular dystrophies. Cardiac disease is a common manifestation,not necessarily related to the degree of skeletal myopathy; it may be the predominant manifestation with or without any other evidence of muscular disease. Death is usually due to ventricular dysfunction,heart block or malignant arrhythmias. Not only DMD/BMD patients,but also female carriers may present cardiac involvement. Clinically overt heart failure in dystrophinopathies may be delayed or absent,due to relative physical inactivity. The commonest electrocardiographic findings include conduction defects,arrhythmias(supraventricular or ventricular),hypertrophy and evidence of myocardial necrosis. Echocardiography can assess a marked variability of left ventricular dysfunction,independently of age of onset or mutation groups. Cardiovascular magnetic resonance(CMR) has documented a pattern of epicardial fibrosis in both dystrophinopathies' patients and carriers that can be observed even if overt muscular disease is absent. Recently,new CMR techniques,such as postcontrast myocardial T1 mapping,have been used in Duchenne muscular dystrophy to detect diffuse myocardial fibrosis. A combined approach using clinical assessment and CMR evaluation may motivate early cardioprotective treatment in both patients and asymptomatic carriers and delay the development of serious cardiac complications.

Arrhythmia risk in liver cirrhosis

Interactions between the functioning of the heart and the liver have been described, with heart diseases affecting the liver, liver diseases affecting the heart, and conditions that simultaneously affect both. The heart is one of the most adversely affected organs in patients with liver cirrhosis. For example, arrhythmias and electrocardiographic changes are observed in patients with liver cirrhosis. The risk for arrhythmia is influenced by factors such as cirrhotic cardiomyopathy, cardiac ion channel remodeling, electrolyte imbalances,impaired autonomic function, hepatorenal syndrome, metabolic abnormalities, advanced age, inflammatory syndrome, stressful events, impaired drug metabolism and comorbidities. Close monitoring of cirrhotic patients is needed for arrhythmias, particularly when QT intervalprolonging drugs are given, or if electrolyte imbalances or hepatorenal syndrome appear. Arrhythmia risk may persist after liver transplantation due to possible QT interval prolongation, persistence of the parasympathetic impairment, post-transplant reperfusion and chronic immunosuppression, as well as consideration of the fact that the transplant itself is a stressful event for the cardiovascular system. The aims of the present article were to provide a review of the most important data regarding the epidemiology, pathophysiology, and biomarkers of arrhythmia risk in patients with liver cirrhosis, to elucidate the association with long-term outcome, and to propose future research directions.

Prevalence of linked angina and gastroesophageal reflux disease in general practice

AIM： To evaluate the association between gastroesophageal reflux diseases （GERD） and coronary heart diseases. METHODS： One thousand nine hundred and seventy consecutive patients who attended our hospital were enrolled. All of the patients who first attend our hospital were asked to respond to the F-scale questionnaire regardless of their chief complaints. All patients had a careful history taken, and resting echocardiography （ECG） was performed by physicians if the diagnostic necessity arose. Patients with ECG signs of coronary artery ischemia were defined as ST- segment depression based on the Minnesota code. RESULTS： Among 712 patients （36%） with GERD, ECG was performed in 171 （24%）, and ischemic changes were detected in eight （5%）. Four （50%） of these patients with abnormal findings upon ECG had no chest symptoms such as chest pain, chest oppression, or palpitations. These patients （0.6%; 4/712） were thought to have non-GERD heartburn, which may be related to ischemic heart disease. Of 281 patients who underwent ECG and did not have GERD symptoms, 20 （7%） had abnormal findings upon ECG. In patients with GERD symptoms and ECG signs of coronary artery ischemia, the prevalence of linked angina was considered to be 0.4% （8/1970 patients）.CONCLUSION： The present study suggested that ischemic heart disease might be found although a patient was referred to the hospital with a complaint of GERD symptoms. Physicians have to be concerned about missing clinically important coronary artery disease while evaluating patients for GERD symptoms.

Exercise-induced left bundle branch block: an infrequent phenomenon: Report of two cases

Exercise-induced left bundle branch block(EI-LBBB)is infrequent phenomenon.We present two patients with angina pectoris who developed EI-LBBB during exercise tolerance test.The first patient with typical angina pectoris had significant obstructive coronary artery disease(CAD)requiring percutaneous coronary intervention of multiple lesions including placement of drug eluting stents.The second patient had atypical chest pain without signs of CAD at all.EI-LBBB occurred at a heart rate of 80 bpm and 141 bpm in the first and second patient,respectively.EI-LBBB remained visible through the test till the recovery period in the first patient at a heart rate of 83 bpm and disappeared at 96bpm in the second patient.Both patients with this infrequent phenomenon are discussed and the literature is reviewed.

Diagnosis of chest pain with foregut symptoms in Chinese patients

AIM:To evaluate the diagnosis of chest pain with foregut symptoms in Chinese patients. METHODS:Esophageal manometric studies, 24-h introesophageal pH monitoring and 24-h electrocardiograms(Holter electrocardiography)were performed in 61 patients with chest pain. RESULTS:Thirty-nine patients were diagnosed with non-specific esophageal motility disorders(29 patients with abnormal gastroesophageal reflux and eight patients with myocardial ischemia).Five patients had diffuse spasm of the esophagus plus abnormal gastroesophageal reflux(two patients had concomitant myocardial ischemia),and one patient was diagnosed with nutcracker esophagus. CONCLUSION:The esophageal manometric studies, 24-h intra-esophageal pH monitoring and Holter electrocardiography are significant for the differential diagnosis of chest pain,particularly in patients with foregut symptoms.In cases of esophageal motility disorders,pathological gastroesophageal reflux may be a major cause of chest pain with non-specific esophageal motility disorders.Spasm of the esophageal smooth muscle might affect the heart-coronary smooth muscle,leading to myocardial ischemia.

ECG stress test induced atrial ischemia in a patient with old inferior myocardial infarction due to a distal coronary artery lesion

A 78-year-old man with a history of mitral valve prolapse underwent echocardiography during his cardiological check-up examination in 2011 in a symptom-free stage. Echocardiography revealed akinesis of the inferior septum and inferobasal free wall as a novel finding suggesting a distal right coronary artery （RCA） lesion （Figure 1）. The systolic left ventricular function was normal. Earlier echocardiographies did not show wall motion abnormalities.

CLINICAL SIGNIFICANCE OF COMPLETE LEFT BUNDLE BRANCH BLOCK IN DILATED CARDIOMYOPATHY

Clinical, electrocardiographic and echocardiographic findings in 64 patients with dilated cardiomyopathy were retrospectively studied. Compared with 51 patients without complete left bundle branch block (CLBBB), 13 patients with CLBBB had higher New York Heart Association (NYHA) functional class (P<0. 05), increased left ventricular end-diastolic and end-systolic diameters (P<0. 002) and myocardial mass (P<0. 02). severe mitral regurgitation (P<0. 01) and higher mortality rate (P<0. 04). Multivariate stepwise regression analysis revealed that the presence of CLBBB was an independent prognostic factor for patients with dilated cardiomyopathy.

Current applications of big data and machine learning in cardiology

Machine learning (ML) is a software solution with the ability of making predictions without prior explicit programming, aiding in the analysis of large amounts of data. These algorithms can be trained through supervised or unsupervised learning. Cardiology is one of the fields of medicine with the highest interest in its applications. They can facilitate every step of patient care, reducing the margin of error and contributing to precision medicine. In particular, ML has been proposed for cardiac imaging applications such as automated computation of scores, differentiation of prognostic phenotypes, quantification of heart function and segmentation of the heart. These tools have also demonstrated the capability of performing early and accurate detection of anomalies in electrocardiographic exams. ML algorithms can also contribute to cardiovascular risk assessment in different settings and perform predictions of cardiovascular events. Another interesting research avenue in this field is represented by genomic assessment of cardiovascular diseases. Therefore, ML could aid in making earlier diagnosis of disease, develop patient-tailored therapies and identify predictive characteristics in different pathologic conditions, leading to precision cardiology.

Acoustic cardiography to improve detection of coronary artery disease with stress testing

AIM:To assess if performance of 12-lead exercise tolerance testing(ETT) can be improved by simultaneous acoustic cardiography and to compare the diagnostic performances of electrocardiography(ECG) during ETT and acoustic cardiography for detection or exclusion of angiographically proven coronary artery disease(CAD).METHODS:We conducted an explorative study with retrospective data analysis using a convenience sample of consecutive patients(n = 59,mean age:62 years) from an outpatient clinic in Switzerland,who were referred for ETT by their general practitioner on suspicion of CAD,and in whom,coronary angiography was carried out.Measurements included sensitivity,specificity,likelihood ratios and receiver operating characteristic curves.A standard,symptom-limited,12-lead ECG exercise tolerance test was performed by independent persons with simultaneous acoustic cardiography and subsequent cardiac angiography for determination of significant CAD.RESULTS:Thirty-four of the 59 adult subjects(58%) had a final diagnosis of CAD by angiography,and in 25 subjects,CAD was excluded by angiography.Sensitivity/specificity of ST segment depression in the group was 29%/92%,whereas the most powerful acoustic cardiographic parameter was the strength of the fourth heart sound(S4),with corresponding sensitivity/specificity of 53%/92%.The disjunctive combination of the S4 and ST depression had sensitivity/specificity of 68%/84%.CONCLUSION:In this preliminary pilot study,the use of acoustic cardiography alone during ETT or disjunctively with ST depression has been shown to be a simple and convenient method for the detection of CAD,which was superior to ST depression on the standardized ECG.

Repetitive narrow QRS tachycardia in a 61-year-old female patient with recent palpitations

A 61-year-old female patient suffering from recent onset palpitations and dyspnea on exertion with hypertension and mitral valve prolapse in her past history came to our outpatient department. Echocardiography revealed a mild mitral valve prolapse, slightly decreased left ventricular （LV） function （LV ejection fraction： 51%） and a mild mitral regurgitation.

Conduction system disorders and electro-cardiographic findings in COVID-19 deceased patients in 2021,Shiraz,Iran

BACKGROUND Cardiac conduction disorders and electrocardiographic(ECG)changes may occur as a manifestation of coronavirus disease 2019(COVID-19),especially in severe cases.AIM To describe conduction system disorders and their association with other electrocardiographic parameters in patients who died of COVID-19.METHODS In this cross-sectional study,electrocardiographic and clinical data of 432 patients who expired from COVID-19 between August 1st,2021,and December 1st,2021,in a tertiary hospital were reviewed.RESULTS Among 432 patients who died from COVID-19,atrioventricular block(AVB)was found in 40(9.3%).Among these 40 patients,28(6.5%)suffered from 1st degree AVB,and 12(2.8%)suffered from complete heart block(CHB).Changes in ST-T wave,compatible with myocardial infarction or localized myocarditis,appeared in 189(59.0%).Findings compatible with myocardial injury,such as fragmented QRS and prolonged QTc,were found in 91 patients(21.1%)and 28 patients(6.5%),respectively.In patients who died of COVID-19,conduction disorder was unrelated to any underlying medical condition.Fragmented QRS,axis deviation,and ST-T changes were significantly related to conduction system disorder in patients who died of COVID-19(P value<0.05).CONCLUSION Conduction system disorders are associated with several other ECG abnormalities,especially those indicative of myocardial ischemia or inflammation.Most patients(73.14%)who died of COVID-19 demonstrated at least one ECG abnormality parameter.Since a COVID-19 patient's ECG gives important information regarding their cardiac health,our findings can help develop a risk stratification method for at-risk COVID-19 patients in future studies.