Lead aVR Research Articles

Electro‐anatomically confirmed sites of origin of ventricular tachycardia and premature ventricular contractions and occurrence of R wave in lead aVR: A proof of concept study

AbstractBackgroundThe R wave in lead aVR, during the wide QRS complex tachycardia, is commonly observed in a ventricular tachycardia (VT) arising from certain locations in the ventricles.ObjectivesThis was a retrospective and a proof of concept study to correlate the sites of origin of VT and premature ventricular contractions (PVCs) with the occurrence of R wave in lead aVR.MethodsPatients with VT or high density of PVCs were included. Surface and intracardiac electrograms were recorded during the arrhythmia. VTs and PVCs arising from the inferior, inferolateral, or apical region of the ventricles were grouped into Zone 2. Those arising from the other areas of the ventricles were grouped into Zone 1.ResultsSixty‐four patients were included in the study. The mean age was 57 years. There were 47 males. Among 64 patients with VT or PVCs, 28 patients had an R wave in aVR (43.7%), In 26 of 28 patients with an R wave in aVR, the site of origin of the arrhythmia was in Zone 2. The R wave in aVR was absent in 36 patients, 34 of whom had the origin of arrhythmia focus in Zone 1. The presence of an R wave in aVR correctly identified Zone 2 as a site of origin of the arrhythmia with high sensitivity (93%) and specificity (94%).ConclusionsThe presence of an R wave in aVR during wide QRS complex tachycardia or PVC is a valuable observation for identifying the site of origin of the arrhythmia and hence in distinguishing supraventricular tachycardia with aberrancy from VT.

Simultaneous ST-elevation in lead augmented vector right (aVR) and III in non-ST-elevation acute coronary syndromes.

The value of ST-elevation in lead augmented vector right (aVR) remains controversial in clinical practice. This study aimed to investigate the association of simultaneous ST-elevation in lead aVR and III with angiographic findings and clinical outcomes in patients with non-ST-elevation acute coronary syndromes (NSTEACS). In this observational study, patients who had been diagnosed with NSTEACS and presented with ST-elevation in lead aVR and without ST-elevation in any other two contiguous leads were enrolled from January 2018 to June 2019. Demographic, baseline clinical, angiographic and interventional characteristics as well as clinical outcomes were collected and recorded on standardized case report forms. A total of 157 patients meeting the criteria were finally enrolled in this study and classified into two groups according to the presence of ST-elevation in lead III. Patients in the two groups were similar in average age and previous history of hypertension, diabetes mellitus, hyperlipidemia, chronic kidney disease, stroke, and peripheral vascular diseases (all P>0.05). Patients with ST-elevation in lead III tended to present with myocardial hypertrophy in the echocardiography (P=0.02). The cases with ST-elevation in lead III showed higher high sensitivity troponin T (hs-TnT; P=0.08) and creatinine kinase MB isoenzyme (CK-MB; P<0.01) whereas those without ST-elevation in lead III showed higher N-terminal pro brain natriuretic peptide (NT-proBNP; P=0.02). Of note, patients with ST-elevation in lead III presented with more ST-depression in multiple leads [especially in lead I, augmented vector left (aVL), V3-V6] as well as higher degree of ST-depression (all P<0.05) and were more likely to develop multi-vessel and left main trunk (LM) lesions (P=0.04), with 20% of the cases having a LM lesion and 60% having triple vessel lesions. Patients with ST-elevation in lead III were at increased risk of 3-year major adverse cardiovascular events (MACEs), despite no significant statistical difference between the two groups (hazard ratio =1.29; P=0.26). The NSTEACS cases with simultaneous ST-elevation in lead III and aVR tended to present with more multiple leads with ST-depression, higher degree of ST-depression, and more LM or multi-vessel lesions, suggesting a broader range of severe myocardial ischemia. The concurrent presentation of ST-elevation in lead III and aVR may play a vital role in the diagnosis, risk-stratification, and prediction of poor prognosis during the management of NSTEACS patients.

Understanding ST equivalents on ECG part II

In reality, many acutemyocardial infarction patients with ST deviations observed in other conditions in which the characteristics of these ECG do not meet the criteria of STEMI. They are called: ST equivalents. STEMI equivalents represent coronary occlusion without meeting the traditional STE criteria and are equally important to recognize in a timely fashion. Emergency physicians must know to involve interventional cardiologists for patients with dynamic ECG changes, persistent ischemic chest pain, hemodynamic instability, and STEMI equivalent patterns that require emergent PCI to minimize morbidity and mortality. This is the reason why we would like to propose this review to present some common ST equivalents for physicians and cardiologists to apply to the clinical practice. These are: de Winter ST/T complex, Wellens syndromes, ST-elevation in lead AVR, LBBB with Sgarbossa criteria, isolated posterior MI, T waves upright in V1. This review is the part two of the topic.

Prevalence and determinants of low QRS voltages and QRS fragmentation in children and adolescents undergoing sports pre-participation screening.

Low QRS voltages (LQRSV) in limb leads and QRS fragmentation (FQRS) are possible electrocardiographic signs of myocardial fibrosis and cardiomyopathy, but they are not listed in current criteria for interpreting athlete's electrocardiogram (ECG). We investigated the prevalence and determinants of LQRSV and FQRS in a cohort of young apparently healthy athletes undergoing pre-participation screening (PPS). We analysed a consecutive series of 2140 ECG obtained during PPS of young athletes (mean age 12.5 ± 2.6 years, 7-18-year-old, 49% males). The peak-to-peak QRS voltage was measured in all limb leads, and LQRSV were defined when maximum value was <0.5 mV. Fragmented QRS morphologies were grouped into five patterns. Lead aVR was not considered. Maximum peak-to-peak QRS voltage in limb leads was 1.4 ± 0.4 mV, similar between younger and older athletes, but significantly lower in females than males (1.35 ± 0.38 mV vs. 1.45 ± 0.42 mV; P < 0.001). There was a weak correlation between maximal QRS voltages and body mass index (BMI), but not with type of sport or training load. Only five (0.2%) individuals showed LQRSV. At least one fragmented QRS complex was identified in 831 (39%) individuals but excluding the rSr' pattern in V1-V2, only 10 (0.5%) showed FQRS in ≥2 contiguous leads. They were older than those without FQRS, but did not differ in terms of gender, BMI, type of sport, or training load. Low QRS voltages in limb leads and FQRS in ≥2 contiguous leads excluding V1-V2 are rare in young apparently healthy athletes and are not related to the type and intensity of sport activity. Therefore, they may require additional testing to rule out an underlying disease particularly when other abnormalities are present.

Prognostic Value of ST-segment Deviation in Lead aVR in Electrocardiogram in Acute Myocardial Infarction

Background: Acute myocardial infarction (AMI) remains a significant cause of morbidity and mortality worldwide, necessitating effective risk stratification tools for improved management. ST-segment deviation in lead augmented vector right (aVR) has emerged as a potential prognostic marker in AMI, but its clinical relevance in the Indian context requires further investigation. Materials and Methods: We conducted a single-center prospective observational study among patients admitted with AMI to assess the prognostic value of ST-segment deviation in lead aVR. Patients were categorized based on the presence or absence of ST-segment deviation in lead aVR, and demographic, clinical, and angiographic characteristics were compared between groups. Follow-up evaluations were performed to assess left ventricular ejection fraction (LVEF) and the incidence of ventricular tachycardia (VT). Results: The study enrolled 110 patients, categorizing them by ST-segment deviation in lead aVR. Patients with ST elevation in lead aVR showed higher moderate LVEF dysfunction (31%–40%) than those with isoelectric ST segments (P = 0.0058). Conversely, patients with ST depression in lead aVR had increased preserved ejection fraction compared to those with an isoelectric ST segment (P = 0.0414). &lt;50% ST-segment resolution postpercutaneous coronary intervention (PCI) was more common among non-ST-segment elevation myocardial infarction (NSTEMI) patients. The incidence of VT was higher in ST elevation in lead aVR (P = 0.0045). Significant differences in ST-segment resolution after PCI (P = 0.0117) between STEMI and NSTEMI patients were noted. Conclusion: ST-segment deviation in lead aVR serves as a valuable prognostic marker in AMI, correlating with adverse outcomes such as moderate LVEF dysfunction and increased risk of VT. Furthermore, its association with ST-segment resolution post-PCI highlights its role in assessing reperfusion success and guiding management strategies. These findings underscore the importance of ST-segment deviation in lead aVR for risk stratification and personalized management in AMI patients.

Early predictors of severe left main and/or three-vessel disease in patients with non-ST-segment elevation myocardial infarction: A dual-center retrospective study.

Early detection of patients concomitant with left main and/or three-vessel disease (LM/3VD) and high SYNTAX score (SS) is crucial for determining the most effective revascularization options regarding the use of antiplatelet medications and prognosis risk stratification. However, there is a lack of study for predictors of LM/3VD with SS in patients with non-ST-segment elevation myocardial infarction (NSTEMI). We aimed to identify potential factors that could predict LM/3VD with high SS (SS > 22) in patients with NSTEMI. This dual-center retrospective study included a total of 481 patients diagnosed with NSTEMI who performed coronary angiography procedures. Clinical factors on admission were collected. The patients were divided into non-LM/3VD, Nonsevere LM/3VD (SS ≤ 22), and Severe LM/3VD (SS > 22) groups. To identify independent predictors, Univariate and logistic regression analyses were conducted on the clinical parameters. A total of 481 patients were included, with an average age of 60.9 years and 75.9% being male. Among these patients, 108 individuals had severe LM/3VD. Based on the findings of a multivariate logistic regression analysis, the extent of ST-segment elevation observed in lead aVR (OR: 7.431, 95% CI: 3.862-14.301, p < .001) and age (OR: 1.050, 95% CI: 1.029-1.071, p < .001) were identified as independent predictors of severe LM/3VD. This study indicated that the age of patients and the extent of ST-segment elevation observed in lead aVR on initial electrocardiogram were the independent predictive factors of LM/3VD with high SS in patients with NSTEMI.

Conditional generative adversarial network driven variable-duration single-lead to 12-lead electrocardiogram reconstruction

The standard 12-lead ECG can represent the cardiac status from twelve different perspectives, while the single-lead ECG just involves a single view, so it is challenging for the single-lead ECG to provide information as rich as the 12-lead ECG. Therefore, this study adopts the improved generative adversarial network (GAN) framework to model the potential mapping relation between single-lead and 12-lead ECG. Taking a heartbeat (1024 points) in lead I as input, in which the R-peak aligning strategy will be used for variable-duration reconstruction. The average correlation coefficients(CC) between the generated and the real signals are 0.742 at the heartbeat level and 0.744 at the segment level, and the CC in lead aVR could be up to 0.91 at the segment level. This study demonstrates that the generated 12-lead ECG signals effectively retain pathological features, thereby providing valuable multi-scale diagnostic information. To assess the efficacy of the diagnostic information derived from the generated signals, this study employs the arrhythmia classifiers for both single-lead and 12-lead ECG, achieving accuracy of 0.71 and 0.81, and macro-F1 scores of 0.66 and 0.77. For the generated 12-lead ECG, the accuracy and macro-F1 for arrhythmia classification could be 0.74 and 0.70, successfully bridging the gap between the single-lead ECG and the 12-lead ECG. In addition, the supplement experiments for other cases have been shown and compared. The source code is available at https://github.com/Zehui-Zhan/12-lead-reconstruction.git.

High Intercostal Space Twelve-Lead ECG in Arrhythmogenic Cardiomyopathy

The value of high intercostal spaces of lead V1 and V2 is analyzed in arrhythmogenic cardiomyopathy. In this ECG writing technique a localized right precorial QRS prolongation and right precordial T-wave inversion can be demonstrated. In normal intercostal spaces only electroanatomic scar and myocardial atrophy documented in lead aVR was present.

Genetic evidence for T-wave area from 12-lead electrocardiograms to monitor cardiovascular diseases in patients taking diabetes medications.

Aims Many studies indicated use of diabetes medications can influence the electrocardiogram (ECG), which remains the simplest and fastest tool for assessing cardiac functions. However, few studies have explored the role of genetic factors in determining the relationship between the use of diabetes medications and ECG trace characteristics (ETC). Methods Genome-wide association studies (GWAS) were performed for 168 ETCs extracted from the 12-lead ECGs of 42,340 Europeans in the UK Biobank. The genetic correlations, causal relationships, and phenotypic relationships of these ETCs with medication usage, as well as the risk of cardiovascular diseases (CVDs), were estimated by linkage disequilibrium score regression (LDSC), Mendelian randomization (MR), and regression model, respectively. Results The GWAS identified 124 independent single nucleotide polymorphisms (SNPs) that were study-wise and genome-wide significantly associated with at least one ETC. Regression model and LDSC identified significant phenotypic and genetic correlations of T-wave area in lead aVR (aVR_T-area) with usage of diabetes medications (ATC code: A10 drugs, and metformin), and the risks of ischemic heart disease (IHD) and coronary atherosclerosis (CA). MR analyses support a putative causal effect of the use of diabetes medications on decreasing aVR_T-area, and on increasing risk of IHD and CA. ConclusionPatients taking diabetes medications are prone to have decreased aVR_T-area and an increased risk of IHD and CA. The aVR_T-area is therefore a potential ECG marker for pre-clinical prediction of IHD and CA in patients taking diabetes medications.

Electrocardiographic Variants of Ventricular Predominance in Arrhythmogenic Cardiomyopathy

Desmoglein-2 and Desmocollin-2 mutations cause different types of arrhythmogenic cardiomyopathy either dominant right, biventricular or dominant left forms. These two mutations present with myocardial cell necrosis and calcification [1,2]. Signs of electrocardiographic right ventricular hypertrophy can be found in more than 50% [3] besides typical ECG criteria of arrhythmogenic cardiomyopathy like right precordial epsilon waves and T-wave inversions [4], QRS fragmentation [5], localized right precordial QRS prolongation [6], terminal activation delay [7], and large Q-waves, small R-waves and T-wave inversion in lead aVR [8].

STEMI and Thyroid Storm: A Case Report of Thyrotoxicosis-Induced Cardiomyopathy

Thyrotoxicosis-induced cardiomyopathy is a rare but potentially fatal form of non-ischemic cardiomyopathy that warrants immediate medical intervention. A 51-year-old female with no known disease sought consultation because of severe chest pain accompanied by easy fatigability and palpitation. Upon arrival at the ED, there was persistence of chest pain accompanied by vomiting, tachycardia and hypotension. ECG showed STEMI in the lead aVR, and she eventually underwent coronary angiogram, which revealed normal coronary arteries. Ancillaries showed severe hyperthyroidism with a Burch – Wartofsky score of 50. There was an elevated NT-proBNP level, and echocardiogram showed a reduced EF of 28.7% with dilated LV and global hypokinesia. She was hooked to a norepinephrine and dobutamine drip and immediately initiated a hyperthyroid regimen, specifically methimazole, propranolol, and steroids. She was admitted to the critical care unit where initiation of SGLT-2 inhibitor and spironolactone were administered as part of the heart failure regimen. When she was out of thyroid storm, a sestamibi myocardial perfusion scan was requested, which showed normal results with improved EF. The goals of management in thyrotoxicosis-induced cardiomyopathy are early initiation of heart failure regimen, medication to prevent further ventricular remodeling, and treatment of thyroid storm. Early recognition and prompt administration of hyperthyroid treatment leads to a decreased burden of the patient’s disease and a good overall prognosis.

Novel electrocardiographic criteria may render possible the more accurate recognition of cardiac amyloidosis.

The early diagnosis of cardiac amyloidosis (CA) is paramount, since there are effective therapies that improve patient survival. The diagnostic accuracy of classical electrocardiographic (ECG) signs, such as low voltage, pseudoinfarct pattern, and conduction disturbances in the diagnosis of CA, is inferior to that of the echocardiographic myocardial deformation criteria; therefore, our aim was to find more accurate novel ECG criteria for this purpose. We tested the diagnostic value of five novel ECG criteria, two of them devised by us, in 34 patients with confirmed CA (20 transthyretin amyloidosis and 14 AL amyloidosis) and 45 control patients with left ventricular hypertrophy on echocardiography due to hypertension, valvular aortic stenosis and hypertrophic cardiomyopathy. The following novel ECG criteria, that suggested CA, were tested: QRS amplitude in lead I<0.55mV (I<0.55); QRS amplitude in lead aVR<0.5mV (aVR<0.5); average QRS amplitude of leads I+aVR<0.575mV [(I+aVR)<0.575]; average QRS amplitude of leads I+aVR/average QRS amplitude of leads V1-4<0.375 [(I+aVR)/(V1-4)<0.375]; average QRS amplitude of leads I+aVR/longest intrinsicoid deflection in leads I,aVL,V1-6<0.0115 [(I+aVR)/I,aVL,V1-6ID<0.0115]. The I<0.55, aVR<0.5, (I+aVR)<0.575, (I+aVR)/(V1-4)<0.375, (I+aVR)/I,aVL,V1-6ID<0.0115 test accuracy (TA) were 81%, 84.8%, 82.3%, 84.8%, and 83.3%, respectively; the sensitivity (SE): 76.5%, 82.4%, 85.3%, 82.4%, and 76.9%; specificity (SP): 84.4%, 86.7%, 80%, 86.7%, and 87.5%; positive predictive values (PPV): 78.8%, 82.4%, 76.3%, 82.4%, and 80%; negative predictive values (NPV): 82.6%, 86.7%, 87.8%, 86.7%, and 85.4%; area under curve (AUC) values: 0.8922, 0.8794, 09016, 0.8824, and 0.8462 were respectively. These parameters of the novel ECG criteria were at least as good as those reported by other authors in the literature of the qualitative (TA: 67%, SE: 80%, SP: 34%, PPV: 75%, NPV: 42%, AUC: 0.57) and quantitative apical sparing (TA: 64-80%, SE: 66-81.3%, SP: 55-78.3%, PPV: 33-83.9%, NPV: 41-75%, AUC: 0.62-0.68) and left ventricular ejection fraction/global longitudinal strain >4.1 (TA: 77%, SE: 93%, SP: 38%, PPV: 79%, NPV: 69%, AUC: 0.65) echocardiographic criteria. Among the classical criteria, the low voltage in limb leads criterion was present most frequently (in 73.5%) in patients with CA, with slightly worse diagnostic value than the novel ECG criteria (TA: 78.5%, SE: 73.5%, SP: 82.2%, PPV: 75.8%, NPV: 80.4%). The novel ECG criteria [mostly the aVR<0.5, (I+aVR)/(V1-4)<0.375] seem at least as reliable in the diagnosis of CA as the best echocardiographic myocardial deformation criteria and might be used either together with the echocardiographic criteria or as stand-alone criteria to diagnose CA in the future.

Importance of Positive T-wave in Lead aVR and Major Adverse Cardiac Events in Patients with ST Elevation Myocardial Infarction: A Cohort Study

Introduction: It is well known that ST-Segment Elevation Myocardial Infarction (STEMI) is a significant contributor to both illness and death on a global scale. An Electrocardiogram (ECG) is an easily accessible bedside tool for diagnosing acute myocardial infarction. The T wave is usually negative in lead aVR (augmented unipolar right arm lead). However, a positive T wave in lead aVR has been shown to be associated with adverse in-hospital outcomes in patients with Acute Coronary Syndrome (ACS). Aim: To examine whether a positive T wave in lead aVR can be used as an indicator to predict Major Adverse Cardiac Events (MACE) during the hospital stay in patients with STEMI. Materials and Methods: A cohort study was performed at Shri BM Patil Medical College, Hospital and Research Centre, Vijayapura, involving patients admitted with STEMI. A total of 98 newly diagnosed ST-segment elevation patients were classified into two groups: Group A (positive T wave) in lead aVR with an amplitude of ≥ 0 mV, and Group B (negative T wave) in lead aVR with an amplitude of ≤0 mV. The hospital stays of STEMI patients were evaluated for adverse cardiac events. Chi-square test was used to assess relationships between categorical variables. Results: A total of 98 patients were evaluated, among which two were excluded. Hence, among 96 patients considered, 25 were females and 71 were male, with average ages of 57 years in Group A and 55 years in Group B. Among the 96 patients, 34 had positive T waves (35.4%) and 62 had negative T waves (64.5%) in lead aVR. The study revealed significantly higher rates of in-hospital MACE (heart failure, pulmonary oedema, and arrhythmias) in patients with positive T waves (Group A) in lead aVR, with p-values &lt;0.05, which were statistically significant. Conclusion: The present study showed that a positive T wave in lead aVR is a valuable and cost-effective tool for predicting inhospital MACE in patients with STEMI. Utilising this simple and readily available ECG measurement could support clinicians in detecting high-risk patients who require closer monitoring and more aggressive interventions, potentially leading to improved patient outcomes and resource allocation.

The "Neglected aVR Lead": Kounis Syndrome of MINOCA Type, Severe Left Main or 3-Vessel Disease and Type A Dissecting Ascending Aortic Aneurysm.

The "Neglected aVR Lead": Kounis Syndrome of MINOCA Type, Severe Left Main or 3-Vessel Disease and Type A Dissecting Ascending Aortic Aneurysm.

Percutaneous coronary intervention in patients admitted with acute coronary syndrome within 6 months after COVID-19 (retrospective single-center study)

BACKGROUND: Assessing clinical manifestations in patients during the period of destabilization of the course of coronary artery disease after COVID-19 coronavirus infection remains a clinical problem. Identifying features of coronary artery lesions in such patients will help to prevent the development of complications and may influence the tactics of active dynamic monitoring.&#x0D; AIM: To evaluate the structure of coronary artery lesions and clinical manifestations in patients with acute coronary syndrome that developed within 6 months after COVID-19 new coronavirus infection.&#x0D; MATERIALS AND METHODS: A comparative analysis of the results of coronary artery stenting in 157 patients admitted with acute coronary syndrome has been carried out. The 1st group included 69 patients who had COVID-19 (vaccinated — 24.6%) during the 6 months preceding acute coronary syndrome; in the 2nd — 88 patients without a history of COVID-19 (vaccinated — 42%). All the patients had drug-eluting stents implanted in the infarct-related artery. Long-term results have been observed in 151 (96.2%) patients.&#x0D; RESULTS: Before the development of acute coronary syndrome, dispnoe was more often observed in patients of the 1st group (36; 52%) than in patients of the 2nd group (13; 14.8%). There were no focal neurological symptoms in the patients of both groups. Dizziness more often preceded acute coronary syndrome in the patients of the 1st group (26; 38.2%) compared to the control group (5; 5.7%). Decreased motivation and fatigue were detected in 27 (67.5%) patients in the 1st group, which was more common than in the 2nd group (13; 32.5%). Acute coronary syndrome with ST elevation was treated in 47 % and 38.6% of the patients in the 1st groups and the 2nd, respectively. The development of acute coronary syndrome with ST segment elevation with previous clinical manifestations of post-covid syndrome in the 1st group was observed in 95.8%, whereas in the absence of post-covid syndrome in 53.3%. The mean value of LVEF in patients who had COVID-19 was 55.9 ± 14%, which was significantly lower than in the patients in the control group (63.2 ± 5.5%; р 0.001). During the course of coronavirus infection in the patients in the first group, lung damage of degrees I–II according to CT scan data was observed in 76.8% of the patients and in 23.2% of degrees III–IV. The frequency of lesions of the circumflex branch in the 1st group was 15.9%, in the 2nd — 11.4% (р = 0.403); of the right coronary artery — 33.3%, and 22.7% (р = 0.41); of the diagonal branch — 5.8%, and 3.4% (р = 0.47); of the left main coronary artery — 5.8%, and 6.8% (р = 0.79), of the left anterior descending branch — 52.2%, and 35.2% (р = 0.033), respectively. The incidence of vasospastic angina in the 1st group was 53.6%, in the 2nd — 15.9% (р 0.0001). ST segment elevation in lead AVR as a manifestation of subendocardial ischemia was registered in the 1st group — 40.6%, the 2nd — 11.4% (р 0.0001). All the patients had drug-eluting stents implanted in the infarct-related artery. Overall survival (in-hospital and long-term) was 100% for the first group and 100 % for the second one.&#x0D; CONCLUSIONS: In the structure of coronary arteries lesions after COVID-19 new coronavirus infection in patients with acute coronary syndrome, damage to the anterior interventricular artery dominates (52.2%). The likelihood of having a left anterior descending lesion during the development of acute coronary syndrome with ST segment elevation in patients who have had COVID-19 is 1.5 times higher. The structure of clinical manifestations after COVID-19 in patients before the development of acute coronary syndrome is dominated by shortness of breath (52 %) and decreased motivation and fatigue (67.5 %).

Giant U Wave: Tanda Bahaya yang Harus Dikenali dalam Praktik Klinik Primer

Introduction: Detection of hypokalaemia by ECG accompanied by detailed history and physical examination will greatly facilitate diagnosis, initiate potassium correction therapy, and prevent further complications due to various cardiac arrhythmias and neurological dysfunctions. Case: A 40-year-old man with weakness in both leg muscles since last night, starting from the legs up to the thighs. Initial ECG showed sinus rhythm with a heart rate at 80 bpm, first-degree heart block (PR interval 240 ms); Q wave in III lead; “apparent” prolonged QTc interval at 551 ms; ST segment depression in I, II, and V3-V6 leads; ST segment elevation in aVR lead; T-wave inseparable from large U wave formed giant U wave that remarkedly seen in V2-V4 leads. Laboratory tests revealed very low serum potassium at 1.94 mmol/L Conclusion: In severe hypokalaemia, T and U waves will merge and form a giant U wave. Emergency and primary physicians should be familiar with the ECG changes of hypokalaemia, especially the giant U wave.

Comparing the Frequency of Left Main Stem Disease Among Patients with ST Elevation in AVR Lead

Background: Coronary artery disease (CAD) is one of the leading causes of mortality worldwide with similar prevalence in Pakistan. The main objective of the study is to compare the frequency of left main stem disease among patients with STelevation in aVR. Methods:This cross-sectionalstudywas conducted inDepartment of cardiology,Punjab institute of cardiology,Lahore. Sample size of 151 cases is calculated with 95% confidence level,7%margin of error and taking expected percentage of LMS is 74.2%. The data was collected through non probability consecutive sampling technique. Results: Mean age of the study population was 55.54±10.1 years. Majority of the cases were male 117(77.5%)and 34(22.5%) were female which were less in quantity. Mean body mass index was 28.61±2.58. Conclusion: Majority of the cases developed left mainstem disease who have been diagnosed with STelevation in aVR. A significant difference of the diabetic versus non diabetic was observed who have been noted for LMS disease.

Predictive factors for type A aortic dissection mortality based on electrocardiogram parameters and clinical presentations.

Aortic dissection is a rare but potentially lethal disorder and may be associated with electrocardiogram (ECG) changes. In this study, we aim to investigate ECG-related parameters alongside clinical presentations of type A aortic dissection to come up with the predictive factors for the severity of the disease and its mortality rate. In this retrospective study, 201 patients with type A aortic dissection were studied between March 2015 and March 2020. Two expert cardiologists blinded to the diagnosis studied former and new patients' ECGs and recorded changes. Two-hundred and one patients, including 143 (71.1%) men and 58 (28.9%) women, presented with acute dissection of the aorta, were studied. Forty-four (21.8%) and 84 (41.7%) patients had ST-segment elevation and depression in ECG, respectively. Bivariate analysis revealed that higher heart rate (p=0.006), longer QTc (p=0.044), and ST-segment elevation in aVR lead (p=0.044) were associated with mortality in the patients. Multivariate regression showed higher heart rate (OR=1.022, CI=1.003-1.041, p=0.012) and ST-segment elevation in aVR (OR=4.854, CI=2.255-10.477, p<0.001) were independently associated with increased odds of mortality in aortic dissection patients. ROC curve analysis showed heart rate equal to or >60 per minute (AUC=0.625, sensitivity=86%, specificity=10%, p=0.019) and ST-segment elevation in aVR >0.5mm (AUC=0.854, sensitivity=75%, specificity=92%, p<0.001) were associated with a higher mortality rate. Heart rate equal or >60 and ST-segment elevation >0.5mm in aVR lead can be used as predictive factors for mortality of patients with type A aortic dissection.

Electrocardiographic characteristics of right-bundle-branch-block premature ventricular complexes predicting absence of left ventricular scar in athletes with apparently structural normal heart.

Left ventricular scar is an arrhythmic substrate that may be missed by echocardiography and diagnosed only by cardiac magnetic resonance (CMR), which is a time-consuming and expensive imaging modality. Premature ventricular complexes (PVCs) with a right-bundle-branch-block (RBBB) pattern are independent predictors of late gadolinium enhancement (LGE) but their positive predictive value is low. We studied which electrocardiographic features of PVCs with an RBBB pattern are associated with a higher probability of the absence of an underlying LGE. The study included 121 athletes (36 ± 16 years; 48.8% men) with monomorphic PVCs with an RBBB configuration and normal standard clinical investigations who underwent CMR. LGE was identified in 35 patients (29%), predominantly in those with PVCs with a superior/intermediate axis (SA-IntA) compared to inferior axis (IA) (38% vs. 10%, P = 0.002). Among patients with SA-IntA morphology, the contemporary presence of qR pattern in lead aVR and V1 was exclusively found in patients without LGE at CMR (51.0% vs. 0%, P < 0.0001). Among patients with IA, the absence of LGE correlated to a narrow ectopic QRS (145 ± 16 vs. 184 ± 27 msec, P < 0.001). Among athletes with apparently idiopathic PVCs with a RBBB configuration, the presence of a concealed LGE at CMR was documented in 29% of cases, mostly in those with a SA-IntA. In our experience, the contemporary presence of qR pattern in lead aVR and V1 in PVCs with RBBB/SA-IntA morphology or, on the other hand, a relatively narrow QRS in PVCs with an IA, predicted absence of LGE.

The Application of a New, Modified Algorithm for the Differentiation of Regular Ventricular and Pre-excited Tachycardias.

The three-step Brugada group algorithm is the only published electrocardiographical (ECG) algorithm for differentiating ventricular tachycardia (VT) from pre-excited tachycardia (PXT) as a cause of regular wide QRS complex tachycardia (WCT). This study aimed to improve the diagnostic accuracy of the Brugada group algorithm. This study modified the Brugada group algorithm by adding a new aVR lead criterion (initial positive deflection in lead aVR and the QRS complex area above the baseline is greater than the area below the baseline). The Brugada group algorithm and the new, modified four-step algorithm in 300 WCT ECGs (241 VTs, 59 PXTs) was applied. If any of the criteria were fulfilled, VT was diagnosed; if none were fulfilled, a diagnosis of PXT was established. The test accuracy, VT diagnosis sensitivity, and negative predictive value (NPV) of the new, modified algorithm were significantly greater than that of the Brugada group algorithm: test accuracy 220 of 300 (73%) vs 182 of 300 (61%); sensitivity 73% vs 55% (p<0.001 for both); NPV 40% vs 31% (p=0.0205). The VT diagnosis specificity of the Brugada group algorithm was greater than that of the new, modified algorithm (83% vs 75%; p=0.019). There was no significant difference between the new, modified and Brugada group algorithms in the positive predictive values (92% vs 93%, respectively) for a VT diagnosis, and positive and negative likelihood ratio values (2.87 vs 3.26; 0.36 vs 0.54, respectively). The new, modified algorithm proved to be more sensitive for the differentiation of VT from PXT than the Brugada group algorithm.