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The evaluation of adult patients suspected of ST-segment elevation myocardial infarction (STEMI) includes a focused history and examination, 12-lead electrocardiogram (ECG), and cardiac serum marker analysis. The ECG plays a pivotal role in the early diagnosis and management of STEMI. A number of ECG entities in this patient population will present with ST-segment elevation and other electrocardiographic abnormalities which can mimic STEMI. In this article, we review the most frequent STEMI mimic patterns, highlight their ECG characteristics, and compare these individual ECG entities to the electrocardiographic abnormalities present with STEMI.

An unexpected major tsunami from the region near Sofu Seamount was observed on 8 October 2023. Sofu Seamount is located approximately 600 km from the coast of Japan. Due to far epicentral distances and the successive occurrence of seismic events, the conventional seismic analysis to reveal the accompanying seismic sequence cannot work well. We investigated high‐frequency teleseismic P and regional T waves from the accompanying seismic sequence during the tsunamigenic events near Sofu Seamount. Envelope shapes of teleseismic P and regional T waves were similar, indicating that T‐wave envelopes also reflected source properties of seismic sequence. During seismic events near Sofu Seamount, observed regional envelopes were characterized by weak body waves and large amplitude T waves with durations of 39–68 s. According to numerical simulations of seismic wave propagation using a realistic topography model, characteristics of T waves exhibit weak slope‐angle and strong source‐depth dependencies. Strong T waves with durations less than 60 s only appeared in results with sources at depths ≤0.5 km below the seafloor. We concluded that high‐frequency radiation of the accompanying seismic sequence during the tsunamigenic events near Sofu Seamount possibly occurred at shallower depths just below the seafloor. If seismic and tsunami sources coincide, shallower source depths might cause tsunamigenic uplifts. The observed peak seafloor uplifts and T‐wave amplitudes during tsunamigenic events were scaled. This result suggests the possibility of tsunami forecasting based on T‐wave amplitudes from submarine volcanoes. Plain Language Summary: On 8 October 2023, an earthquake sequence, which included 15 moderate‐size (magnitudes of 4.3–5) earthquakes, was observed in the region near Sofu Seamount. When a moderate‐size (M < 6) earthquake occurs in offshore regions, we generally observe no tsunami signals. However, during this earthquake sequence, an unexpected major tsunami was observed along the coast of Japan. To investigate tsunami sources near Sofu Seamount, we analyzed observed T waves at ocean‐bottom seismometers near the coast of southwest Japan. T waves are ocean acoustic waves and can effectively propagate at distances larger than several thousand kilometers. Observed T waves were significant compared with P waves, propagating through the subsurface. We also analyzed simulation results of high‐frequency seismic wave propagation from Sofu Seamount to the Japanese coast. Comparing simulation results with observed T waves allows us to constrain the depth of moderate‐size earthquakes. Because efficient T‐wave generation only appears in shallower sources, moderate‐size earthquakes should be located at depths ≤0.5 km below the seafloor, and such shallower seismic/deformation phenomena might cause observable tsunamis even for magnitudes ≤5. Key Points: We studied high‐frequency teleseismic P and regional T waves during tsunamigenic events near Sofu SeamountAccording to envelope shapes, accompanying seismic events during tsunamigenic events should be at depths ≤0.5 km below the seafloorShallow sources might cause tsunamigenic seafloor uplifts even for smaller seismic magnitudes [ABSTRACT FROM AUTHOR]

The evaluation of adult patients suspected of ST-segment elevation myocardial infarction (STEMI) includes a focused history and examination, 12-lead electrocardiogram (ECG), and cardiac serum marker analysis. The ECG plays a pivotal role in the early diagnosis and management of STEMI. A number of ECG entities in this patient population will present with ST-segment elevation and other electrocardiographic abnormalities which can mimic STEMI. In this article, we review the most frequent STEMI mimic patterns, highlight their ECG characteristics, and compare these individual ECG entities to the electrocardiographic abnormalities present with STEMI. [ABSTRACT FROM AUTHOR]

Abstract An electrocardiogram is a medical examination tool for measuring different patterns of heart blood flow circle either in the form of usual or non-invasive patterns. These patterns are useful for the identification of morbidity condition of the heart especially in certain conditions of heart abnormality and arrhythmia. Myocardial infarction (MI) is one of them that happened due to sudden blockage of blood by the cause of malfunction of heart. In electrocardiography (ECG) intensity of MI is highlighted on the basis of unusual patterns of T wave changes. Various studies have contributed for MI through T wave’s classification, but more to the point of T wave has always attracted the ECG researchers. Methodology. This Study is primarily designed for proposing the combination of latest methods that are worked for the solutions of pre-defined research questions. Such solutions are designed in the form of the systematic review process (SLR) by following the Kitchen ham guidance. The literature survey is a two phase’s process, at first phase collect the articles that were published in IEEE Xplore, Scopus, science direct and Springer from 2008 to 2023. It consist of steps; the first level is executed by filtrating the articles on the basis of keyword phase of title and abstract filter. Similarly, at two level the manuscripts are scanned through filter of eligibility criteria of articles selection. The last level belongs to the quality assessment of articles, in such level articles are rectified through evaluation of domain experts. Results. Finally, the selected articles are addressed with research questions and briefly discuss these selected state-of-the-art methods that are worked for the T wave classification. These address units behave as solutions to research problems that are highlighted in the form of research questions. Conclusion and future directions. During the survey process for these solutions, we got some critical observations in the form of gaps that reflected the other directions for researchers. In which feature engineering, different dependencies of ECG features and dimensional reduction of ECG for the better ECG analysis are reflection of future directions.

Objective: ST segment deviations around the isoelectric line are common findings in manifest cardiovascular disease. In athletes, ST elevation is common, while ST depression is considered rare. However, clinical studies in athletes have associated ST depression with myocardial fibrosis and fatty infiltration and ST elevation with pericarditis and myocarditis. This study aims to explore the association between resting ST segment deviations and resting heart rate, an indicator of training and autonomic tone and electrocardiography (ECG) markers of exercise training effect and cardiovascular health R and T wave amplitude. Design: Retrospective analysis of digitized ECG data. Setting: Institutional setting. Participants: Seven thousand eight hundred thirty-six (male athletes = 4592, female athletes = 3244) healthy asymptomatic athletes (14-35 years). Main outcome measures: A series of correlations and regressions were conducted between ST depression (<0.0 µV) and ST elevation (>0.0 µV), on R and T wave amplitudes, and heart rate in leads V2, V5, and aVF. Results: Positive correlations between ST elevation and R and T wave (S wave in V2) amplitudes and leads V5, V2, and aVF in male and female athletes (range of r = 0.1-0.54). In addition, there was a negative correlation between ST elevation and HR for male and female athletes. Finally, there was a negative correlation between ST depression and R wave and HR for male and female athletes in V5 ( P < 0.01). Conclusions: In athletes, ST segment elevation is correlated with R and T wave amplitudes and negatively correlated with HR. In addition, ST segment elevation is correlated with low heart rate, consistent with its higher prevalence in athletes. ST segment depression is not influenced by HR but is negatively associated with R and T wave amplitudes. [ABSTRACT FROM AUTHOR]

An electrocardiogram is a medical examination tool for measuring different patterns of heart blood flow circle either in the form of usual or non-invasive patterns. These patterns are useful for the identification of morbidity condition of the heart especially in certain conditions of heart abnormality and arrhythmia. Myocardial infarction (MI) is one of them that happened due to sudden blockage of blood by the cause of malfunction of heart. In electrocardiography (ECG) intensity of MI is highlighted on the basis of unusual patterns of T wave changes. Various studies have contributed for MI through T wave's classification, but more to the point of T wave has always attracted the ECG researchers. Methodology. This Study is primarily designed for proposing the combination of latest methods that are worked for the solutions of pre-defined research questions. Such solutions are designed in the form of the systematic review process (SLR) by following the Kitchen ham guidance. The literature survey is a two phase's process, at first phase collect the articles that were published in IEEE Xplore, Scopus, science direct and Springer from 2008 to 2023. It consist of steps; the first level is executed by filtrating the articles on the basis of keyword phase of title and abstract filter. Similarly, at two level the manuscripts are scanned through filter of eligibility criteria of articles selection. The last level belongs to the quality assessment of articles, in such level articles are rectified through evaluation of domain experts. Results. Finally, the selected articles are addressed with research questions and briefly discuss these selected state-of-the-art methods that are worked for the T wave classification. These address units behave as solutions to research problems that are highlighted in the form of research questions. Conclusion and future directions. During the survey process for these solutions, we got some critical observations in the form of gaps that reflected the other directions for researchers. In which feature engineering, different dependencies of ECG features and dimensional reduction of ECG for the better ECG analysis are reflection of future directions. [ABSTRACT FROM AUTHOR]

• Minor ECG abnormalities are prevalent in pediatric epilepsy patients without cardiac concerns. • Nonspecific ST segment and t wave abnormalities are the most common changes observed. • Of the clinical factors examined, only epilepsy duration is independently associated with ECG abnormalities. • The association may reflect cardiac changes as result of chronic epilepsy, which is consistent with the concept of the "epileptic heart". Cardiac abnormalities resulting from chronic epilepsy ("the epileptic heart") constitute a well-recognized comorbidity. However, the association of cardiac alterations with epilepsy duration remains understudied. We sought to evaluate this association using electrocardiogram (ECG). We prospectively enrolled children between 1 months and 18 years of age without known cardiac conditions or ion channelopathies during routine clinic visits. ECGs were categorized as abnormal if there were alterations in rhythm; PR, QRS, or corrected QT interval; QRS axis or morphology; ST segment or T wave. An independent association between ECG abnormalities and epilepsy duration was evaluated using multivariable logistic regression modeling. 213 children were enrolled. 100 ECGs (47%) exhibited at least one alteration; most commonly in the ST segment (37, 17%) and T wave (29, 11%). Children with normal ECGs had shorter epilepsy duration as compared to those with ECG abnormalities (46 [18–91] months vs. 73 [32–128 months], p = 0.004). A multivariable logistic regression model demonstrated that increasing epilepsy duration was independently associated with the presence of ECG abnormalities (OR=1.09, 95% CI=1.02–1.16, p = 0.008), adjusted for seizure frequency, generalized tonic-clonic/focal to bilateral tonic-clonic seizures as the predominant seizure type, and number of channel-modifying anti-seizure medications. Increasing epilepsy duration was also independently associated with the presence of ST/T wave abnormalities (OR=1.09, 95% CI=1.01–1.16, p = 0.017), adjusted for the same covariates. Increasing epilepsy duration is independently associated with the presence of minor ECG abnormalities. Additional studies are needed to evaluate whether this finding may represent a manifestation of the "epileptic heart". [ABSTRACT FROM AUTHOR]

Background: Twelve‐lead electrocardiogram (ECG) is a common and inexpensive tool for the diagnostic workup of patients with suspected cardiovascular disease, both in clinical and epidemiological settings. The present study was designed to evaluate ECG abnormalities in Mashhad population. Methods: ECGs were taken as part of MASHAD cohort study (phase1) and were coded according to the Minnesota coding criteria. Data were analyzed using SPSS. Results: Total 9035 ECGs were available for final analysis including 3615 (40.0%) male and 5420 (60.0%) female. Among ECG abnormalities precordial Q wave, major T‐wave abnormalities, inferior Q wave, sinus bradycardia, and left axis deviation were the most prevalent abnormalities. The frequency of precordial and inferior Q wave, inferior QS pattern, major and minor ST abnormalities, major and minor T abnormalities, Wolff‐Parkinson‐White and Brugada pattern, sinus bradycardia, sinus tachycardia, left axis deviation, ST elevation, and tall T wave were significantly different between two genders. Moreover, the frequency of Q wave in precordial and aVL leads, QS pattern in precordial and inferior leads, major and minor T‐wave abnormalities, Wolff‐Parkinson‐White, atrial fibrillation, sinus bradycardia, left axis deviation, and ST elevation were significantly different in different age groups. A comparison of the heart rate, P‐wave duration, and QRS duration between men and women indicated that there was a significant difference. Conclusions: Our finding indicated that the prevalence ECG abnormalities are different between men and women and also it varied in different age groups. [ABSTRACT FROM AUTHOR]

Abstract Background Twelve‐lead electrocardiogram (ECG) is a common and inexpensive tool for the diagnostic workup of patients with suspected cardiovascular disease, both in clinical and epidemiological settings. The present study was designed to evaluate ECG abnormalities in Mashhad population. Methods ECGs were taken as part of MASHAD cohort study (phase1) and were coded according to the Minnesota coding criteria. Data were analyzed using SPSS. Results Total 9035 ECGs were available for final analysis including 3615 (40.0%) male and 5420 (60.0%) female. Among ECG abnormalities precordial Q wave, major T‐wave abnormalities, inferior Q wave, sinus bradycardia, and left axis deviation were the most prevalent abnormalities. The frequency of precordial and inferior Q wave, inferior QS pattern, major and minor ST abnormalities, major and minor T abnormalities, Wolff‐Parkinson‐White and Brugada pattern, sinus bradycardia, sinus tachycardia, left axis deviation, ST elevation, and tall T wave were significantly different between two genders. Moreover, the frequency of Q wave in precordial and aVL leads, QS pattern in precordial and inferior leads, major and minor T‐wave abnormalities, Wolff‐Parkinson‐White, atrial fibrillation, sinus bradycardia, left axis deviation, and ST elevation were significantly different in different age groups. A comparison of the heart rate, P‐wave duration, and QRS duration between men and women indicated that there was a significant difference. Conclusions Our finding indicated that the prevalence ECG abnormalities are different between men and women and also it varied in different age groups.

Background: The optimal way to determine repolarization time (RT) from the intracardiac unipolar electrogram (UEG) has been a topic of debate for decades. RT is typically determined by either the Wyatt method or the "alternative method," which both consider UEG T-wave slope, but differently. Objective: To determine the optimal method to measure RT on the UEG. Methods: Seven pig hearts surrounded by an epicardial sock with 100 electrodes were Langendorff-perfused with selective cannulation of the left anterior descending (LAD) coronary artery and submersed in a torso-shaped tank containing 256 electrodes on the torso surface. Repolarization was prolonged in the non-LAD-regions by infusing dofetilide and shortened in the LAD-region using pinacidil. RT was determined by the Wyatt (tWyatt) and alternative (tAlt)methods, in both invasive (recorded with epicardial electrodes) and in non-invasive UEGs (reconstructed with electrocardiographic imaging). tWyatt and tAlt were compared to local effective refractory period (ERP). Results: With contact mapping, mean absolute error (MAE) of tWyatt and tAlt vs. ERP were 21 ms and 71 ms, respectively. Positive T-waves typically had an earlier ERP than negative T-waves, in line with theory. tWyatt -but not tAlt-shortened by local infusion of pinacidil. Similar results were found for the non-invasive UEGs (MAE of tWyatt and tAlt vs. ERP were 30 ms and 92 ms, respectively). Conclusion: The Wyatt method is the most accurate to determine RT from (non) invasive UEGs, based on novel and historical analyses. Using it to determine RT could unify and facilitate repolarization assessment and amplify its role in cardiac electrophysiology. [ABSTRACT FROM AUTHOR]

Background: The optimal way to determine repolarization time (RT) from the intracardiac unipolar electrogram (UEG) has been a topic of debate for decades. RT is typically determined by either the Wyatt method or the “alternative method,” which both consider UEG T-wave slope, but differently.Objective: To determine the optimal method to measure RT on the UEG.Methods: Seven pig hearts surrounded by an epicardial sock with 100 electrodes were Langendorff-perfused with selective cannulation of the left anterior descending (LAD) coronary artery and submersed in a torso-shaped tank containing 256 electrodes on the torso surface. Repolarization was prolonged in the non-LAD-regions by infusing dofetilide and shortened in the LAD-region using pinacidil. RT was determined by the Wyatt (tWyatt) and alternative (tAlt) methods, in both invasive (recorded with epicardial electrodes) and in non-invasive UEGs (reconstructed with electrocardiographic imaging). tWyatt and tAlt were compared to local effective refractory period (ERP).Results: With contact mapping, mean absolute error (MAE) of tWyatt and tAlt vs. ERP were 21 ms and 71 ms, respectively. Positive T-waves typically had an earlier ERP than negative T-waves, in line with theory. tWyatt -but not tAlt-shortened by local infusion of pinacidil. Similar results were found for the non-invasive UEGs (MAE of tWyatt and tAlt vs. ERP were 30 ms and 92 ms, respectively).Conclusion: The Wyatt method is the most accurate to determine RT from (non) invasive UEGs, based on novel and historical analyses. Using it to determine RT could unify and facilitate repolarization assessment and amplify its role in cardiac electrophysiology.

Intervals of low-quality photoplethysmogram (PPG) signals might lead to significant inaccuracies in estimation of pulse arrival time (PAT) during polysomnography (PSG) studies. While PSG is considered to be a "gold standard" test for diagnosing obstructive sleep apnea (OSA), it also enables tracking apnea-related nocturnal blood pressure fluctuations correlated with PAT. Since the electrocardiogram (ECG) is recorded synchronously with the PPG during PSG, it makes sense to use the ECG signal for PPG signal-quality assessment. (1) Objective: to develop a PPG signal-quality assessment algorithm for robust PAT estimation, and investigate the influence of signal quality on PAT during various sleep stages and events such as OSA. (2) Approach: the proposed algorithm uses R and T waves from the ECG to determine approximate locations of PPG pulse onsets. The MESA database of 2055 PSG recordings was used for this study. (3) Results: the proportions of high-quality PPG were significantly lower in apnea-related oxygen desaturation (matched-pairs r c = 0.88 and r c = 0.97, compared to OSA and hypopnea, respectively, when p < 0.001) and arousal ( r c = 0.93 and r c = 0.98, when p < 0.001) than in apnea events. The significantly large effect size of interquartile ranges of PAT distributions was between low- and high-quality PPG (p < 0.001, r c = 0.98), and regular and irregular pulse waves (p < 0.001, r c = 0.74), whereas a lower quality of the PPG signal was found to be associated with a higher interquartile range of PAT across all subjects. Suggested PPG signal quality-based PAT evaluation reduced deviations (e.g., r c = 0.97, r c = 0.97, r c = 0.99 in hypopnea, oxygen desaturation, and arousal stages, respectively, when p < 0.001) and allowed obtaining statistically larger differences between different sleep stages and events. (4) Significance: the implemented algorithm has the potential to increase the robustness of PAT estimation in PSG studies related to nocturnal blood pressure monitoring. [ABSTRACT FROM AUTHOR]

Macromastia is associated with symptoms related to postural changes and decreased mobility. Breast reduction surgery (BRS) is the treatment of choice for these patients. Anatomical and structural changes in body posture and habitus might cause changes in electrocardiography (ECG). In this study, we aimed to evaluate the outcome of BRS on ECG changes of the patients after surgery. Study population included 33 female patients who had undergone BRS. ECG records of every patient before procedure and 6 months after procedure were analyzed retrospectively. Patients were naïve of known cardiac diseases and the patients did not have any known arrhythmia. The mean age of the study population was 40.8 ± 9.6. Total removed breast tissue from both sides was 1493 (1052–2138) mL, as 800 (513–1093) mL removed from right side and 740 (519–1050) mL removed from left side. There were significant changes in ECG of the patients in post-operative period. Atrial conduction parameters such as, PR duration (p<.001), Pmax duration (p<.001) and P wave dispersion (p<.001) were significantly decreased post-operatively. Additionally, ventricular conduction parameters such as, TPe duration (p<.001), TPe/QT (p=.013) and TPe/QTc (p=.005) ratios were found significantly decreased in ECGs of the patients. BRS as a treatment for macromastia does not only improve posture and mobility of the patients and also have positive impact on cardiac conductions. In patients those had BRS, atrial and ventricular conductions detected by ECG recordings were improved after surgery. [ABSTRACT FROM AUTHOR]

Purpose: The Tpeak-Tend interval of the T wave has emerged as a new electrocardiographic marker of increased transmural dispersion of ventricular repolarization. We aimed to determine the presence of cardiac conduction system disorders in patients with systemic arterial hypertension (SAH) who have altered Tpeak-Tend interval of the T wave. Methods: The 67 patients with SAH were divided into two groups. Those with prolonged (= 77 ms) Tpeak-Tend intervals, 21 (31%) patients were in the study group. Those with normal (< 77 ms) Tpeak-Tend intervals, 46 (69%) patients were in the control group. Alteration of ventricular repolarization manifested as a prolongation of the Tpeak-Tend interval was detected by computerized electrocardiographic analysis tools. Results: The median value of QRS complex duration was significantly wider in the study group as compared to the control group (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). There was a significantly greater incidence of left anterior hemiblock in the study group (14% vs. 0% p < 0.04). The median value of the QTc interval was significantly greater in the study group (440 ± 26 vs. 422 ± 15 p < 0.01). There was a significantly greater incidence of patients with prolonged QTc interval in the study group (33% vs. 11% p < 0.02). The median value of the Tpeak-Tend interval was significantly greater in the study group (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), as well as, the Tpeak-Tend/QTc ratio in the study group (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). Conclusion: There is a significantly greater ventricular repolarization disorders and abnormalities of the cardiac conduction system in SAH patients who possess altered Tpeak-Tend interval of the T wave. [ABSTRACT FROM AUTHOR]

Background: Wearable technologies for monitoring cardiovascular parameters, including electrocardiography (ECG) and impedance cardiography (ICG), propose a challenging research subject. The expectancy for wearable devices to be unobtrusive and miniaturized sets a goal to develop smarter devices and better methods for signal acquisition, processing, and decision-making. Methods: In this work, non-standard electrode placement configurations (EPC) on the thoracic area and single arm were experimented for ECG signal acquisition. The locations were selected for joint acquisition of ECG and ICG, targeted to suitability for integrating into wearable devices. The methodology for comparing the detected signals of ECG was developed, presented, and applied to determine the R, S, and T waves and RR interval. An algorithm was proposed to distinguish the R waves in the case of large T waves. Results: Results show the feasibility of using non-standard EPCs, manifesting in recognizable signal waveforms with reasonable quality for post-processing. A considerably lower median sensitivity of R wave was verified (27.3%) compared with T wave (49%) and S wave (44.9%) throughout the used data. The proposed algorithm for distinguishing R wave from large T wave shows satisfactory results. Conclusions: The most suitable non-standard locations for ECG monitoring in conjunction with ICG were determined and proposed. [ABSTRACT FROM AUTHOR]

We herein report an 80-year-old man showing a downsloping TP segment together with an increase in the height of the T wave in the precordial leads on a standard 12-lead electrocardiogram (ECG). Separately, an 87-year-old woman showed only a downsloping TP segment in the precordial leads on a standard 12-lead ECG. Neither patient reported chest pain or dyspnea when ECGs was obtained. This downsloping TP segment in the precordial leads on the standard 12-lead ECG is thought to be due to a cardiac impulse-tapping artifact. Differential diagnoses are also discussed.

Continuous electrocardiographic (ECG) monitoring remains crucial during surgery in infants and children. Although generally uncommon in pediatric-aged patients, ECG changes may occasionally be indicative of a variety of myocardial pathologies including anomalous origin of coronary arteries, ventricular hypertrophy, myocarditis, hypothermia, drug effects, electrolyte abnormalities, acid-base disturbances or conduction system disorders such as Wolff-Parkinson-White and Brugada syndrome. Distinguishing between pathologic and non-pathologic conditions impacting the ECG must be considered so that appropriate interventions are provided to prevent perioperative morbidity and mortality. We report a case of a 2-year-old child who exhibited ST segment depression and increased R wave amplitude during general anesthesia. Although the anesthetic care was uneventful and the patient was otherwise asymptomatic, immediate postoperative workup including echocardiogram revealed previously undiagnosed hypertrophic cardiomyopathy. The occurrence of intraoperative ST-T wave changes in this patient underscores the need for a high index of suspicion for underlying cardiac pathology, even in the absence of overt clinical manifestations. This case highlights the importance of intraoperative ECG monitoring in pediatric patients, explores the causes of ST-T wave changes, reviews similar cases in the literature, and proposes a pathway for perioperative evaluation., Competing Interests: None to declare., (Copyright 2024, Gadelsayed et al.)

Identification of arrhythmogenic right ventricular cardiomyopathy (ARVC) during childhood is challenging due to the lack of specific ECG manifestation. We report chronological ECG alteration before several years of the ARVC onset in two affected children. Their ECG at the age of 6 years was almost normal for their age, and their chronological ECGs exhibited inversion of T wave in inferior leads, which are typical for ARVC, developed at younger age than that in precordial leads. In addition, the leftmost T‐wave inversion in the precordial lead shifted toward the left in our patients, which is a sharp contrast to its physiological transition. [ABSTRACT FROM AUTHOR]

The risk stratification and early interventions are necessary in patients with hypertrophic cardiomyopathy (HCM), as life-threatening arrhythmia (LTA) is a leading cause of death. This study aimed to explore whether an interval between the peak of the T wave to the end terminal of the T wave (Tp-e), which represents ventricular repolarization dispersion, could predict the risk for LTA in children with HCM. We analyzed electrocardiography at the first and last visits in children (aged < 15 years) with HCM, and compared Tp-e interval and the ratio of Tp-e interval to QT interval (Tp-e/QT) between children with and without LTA. We studied 25 children with HCM. During the follow-up of 85 (38–146) months, there were 7 children with LTA. The 5-year sudden cardiac death (SCD) risk was 1.4 (1.1–2.5) %, which suggested that our cohort consisted of patients at a lower risk for SCD. Age was significantly older in children with LTA compared to those without it (12.5 vs.1.0 years, P = 0.037), although sex, the presence of family history and symptoms at diagnosis, the maximum left ventricular wall thickness Z-score did not differ between the groups. At the last electrocardiography before LTA, corrected Tp-e interval and Tp-e/QT ratio were significantly greater in patients with LTA compared to those in patients without LTA (corrected Tp-e: 103 vs. 78 ms, P = 0.020; Tp-e/QT: 0.28 vs. 0.22, P = 0.046). Corrected Tp-e and Tp-e/QT ratio cutoff values of 91 ms and 0.28 yielded as the predictors for LTA with sensitivity of 85% and 72%, specificity of 71% and 89%, respectively. Prolonged absolute and corrected Tp-e intervals and an increase in the Tp-e/QT ratio can be useful predictors for LTA in children with HCM. We offer temporal assessments of ventricular repolarization dispersion to stratify the risk for the development of LTA/SCD among children with HCM. [ABSTRACT FROM AUTHOR]

Abstract Background aVR lead is often neglected in routine clinical practice largely because of its undefined clinical utility specifications. Nevertheless, positive T-wave in aVR lead has been reported to be associated with poor clinical outcomes in some cardiovascular diseases. This study aimed to prospectively investigate the prognostic value and clinical utility of T-wave amplitude in aVR lead in patients with acute ST-elevation myocardial infarction (STEMI). Methods A total of 340 STEMI patients admitted to a tertiary heart center were consecutively included. Patients were categorized into four strata, based on T wave amplitude in aVR lead in their admission ECG (i.e.

Abstract Identification of arrhythmogenic right ventricular cardiomyopathy (ARVC) during childhood is challenging due to the lack of specific ECG manifestation. We report chronological ECG alteration before several years of the ARVC onset in two affected children. Their ECG at the age of 6 years was almost normal for their age, and their chronological ECGs exhibited inversion of T wave in inferior leads, which are typical for ARVC, developed at younger age than that in precordial leads. In addition, the leftmost T‐wave inversion in the precordial lead shifted toward the left in our patients, which is a sharp contrast to its physiological transition.

Background: Acute coronary occlusion results in increased T-wave amplitude and ST-segment elevation in the ECG leads facing the ischemic region.Material and Methods: We performed continuous ECG recording in 34 patients during balloon occlusion of the left anterior descending (LAD), left circumflex (LCx) and right coronary artery (RCA). Delta (Δ) ST and ΔT amplitudes were calculated by subtracting the preinflation values from the values measured during balloon inflation.Results: Occlusion of the LAD resulted in greater increase in the amplitude of the T wave than of the ST segment in lead V2 (ΔT +3.4 mm, inter-quartile range [IQR] 1-6 mm; ΔST +1.4 mm, 0.5-3 mm). During RCA occlusion, ΔST and ΔT didn't differ significantly. LCx occlusion resulted in significant differences between ΔST and ΔT in all leads, except aVF and V3-V4. In two patients (LCx), we observed a biphasic ST-T response: an initial negative change of the T-wave amplitude was followed by a positive change in leads V1-V2. In leads II, III, aVF and V4-V6, there was an initial positive change, followed by a final negative change towards the end of the occlusion.Conclusion: Continuous 12‑lead ECG recording during balloon occlusion of the LCx resulted in significant differences between the ΔST and ΔT values in all leads except aVF and V3-V4. LAD and RCA occlusion resulted in less evident differences between the ST-segment and T-wave changes. A change in polarity of T-wave changes during balloon occlusion (initial negative and final positive change, or vice versa) proved to be a rare finding. [ABSTRACT FROM AUTHOR]

Background: Altered ventricular depolarization due to manifest accessory pathway conduction (ie, Wolff-Parkinson-White syndrome) leads to repolarization abnormalities that persist after pathway ablation. The term T-wave memory (TWM) has been applied to these changes, as the postablation T-wave vector "remembers" the pre-excited QRS vector. In adults, these abnormalities can be misinterpreted as ischemia leading to unnecessary interventions. To date, no comprehensive studies have evaluated this phenomenon in the pediatric population.Objective: The purpose of this study was to define TWM in the pediatric population, identify preablation risk factors, and delineate the timeline of recovery.Methods: Pre- and postablation electrocardiograms (ECGs) in patients ≤25 years were analyzed over a 5-year period. Frontal plane QTc interval, T-wave axis, QRST angle, and T-wave inversions were used to identify patients with TWM. Univariate analysis was performed to determine the association of preablation ECG features with the outcome of TWM.Results: TWM was present in 42% of pediatric patients, with resolution occurring within 3 months of ablation. Preablation QRS axis <0° was a strong predictor of TWM (odds ratio [OR] 15.2; 95% confidence interval [CI] 5.7-40), followed by posteroseptal pathway location (right posteroseptal-OR 8.9; 95% CI 4.2-18.8; left posteroseptal-OR 6.1; 95% CI 1.7-22.3). The degree of pre-excitation had a modest association with the development of TWM. No adverse events were observed.Conclusion: TWM is less common in children compared to adults, and normalization occurred within 3 months postablation. The most predictive features for the development of TWM include a leftward pre-excited QRS axis and posteroseptal pathway location. [ABSTRACT FROM AUTHOR]

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody, a dermatomyositis (DM)-specific antibody, is strongly associated with interstitial lung disease (ILD). Patients with idiopathic inflammatory myopathy (IIM) who are anti-MDA5 antibody positive [anti-MDA5 (+)] often experience chest symptoms during the active disease phase. These symptoms are primarily explained by respiratory failure; nevertheless, cardiac involvement can also be symptomatic. Thus, the aim of this study was to investigate cardiac involvement in anti-MDA5 (+) DM. A total of 63 patients with IIM who underwent electrocardiography (ECG) and ultrasound cardiography (UCG) during the active disease phase from 2016 to 2021 [anti-MDA5 (+) group, n = 21; anti-MDA5-negative (-) group, n = 42] were enrolled in the study, and their clinical charts were retrospectively reviewed. The ECG and UCG findings were compared between the anti-MDA5 (+) and anti-MDA5 (-) groups. All anti-MDA5 (+) patients had DM with ILD. The anti-MDA5 (+) group showed more frequent skin ulcerations and lower levels of leukocytes, muscle enzymes, and electrolytes (Na, K, Cl, and Ca) than the anti-MDA5 (-) group. According to the ECG findings obtained during the active disease phase, the T wave amplitudes were significantly lower for the anti-MDA5 (+) group than for the anti-MDA5 (-) group (I, II, and V4–6 lead; p < 0.01; aVF and V3, p < 0.05). However, the lower amplitudes were restored during the remission phase. Except for the E wave, A wave and Sep e’, the UCG results showed no significant differences between the groups. Four patients with anti-MDA5 (+) DM had many leads with lower T wave and cardiac abnormalities (heart failure, diastolic dysfunction, myocarditis) on and after admission. Though anti-MDA5 (+) patients clinically improved after immunosuppressive therapy, some of their ECG findings did not fully recover in remission phase. In conclusion, anti-MDA5 (+) DM appears to show cardiac involvement (electrical activity and function) during the active phase. Further studies are necessary to clarify the actual cardiac condition and mechanism of these findings in patients with anti-MDA5 (+) DM.

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody, a dermatomyositis (DM)-specific antibody, is strongly associated with interstitial lung disease (ILD). Patients with idiopathic inflammatory myopathy (IIM) who are anti-MDA5 antibody positive [anti-MDA5 (+)] often experience chest symptoms during the active disease phase. These symptoms are primarily explained by respiratory failure; nevertheless, cardiac involvement can also be symptomatic. Thus, the aim of this study was to investigate cardiac involvement in anti-MDA5 (+) DM. A total of 63 patients with IIM who underwent electrocardiography (ECG) and ultrasound cardiography (UCG) during the active disease phase from 2016 to 2021 [anti-MDA5 (+) group, n = 21; anti-MDA5-negative (-) group, n = 42] were enrolled in the study, and their clinical charts were retrospectively reviewed. The ECG and UCG findings were compared between the anti-MDA5 (+) and anti-MDA5 (-) groups. All anti-MDA5 (+) patients had DM with ILD. The anti-MDA5 (+) group showed more frequent skin ulcerations and lower levels of leukocytes, muscle enzymes, and electrolytes (Na, K, Cl, and Ca) than the anti-MDA5 (-) group. According to the ECG findings obtained during the active disease phase, the T wave amplitudes were significantly lower for the anti-MDA5 (+) group than for the anti-MDA5 (-) group (I, II, and V4–6 lead; p < 0.01; aVF and V3, p < 0.05). However, the lower amplitudes were restored during the remission phase. Except for the E wave, A wave and Sep e', the UCG results showed no significant differences between the groups. Four patients with anti-MDA5 (+) DM had many leads with lower T wave and cardiac abnormalities (heart failure, diastolic dysfunction, myocarditis) on and after admission. Though anti-MDA5 (+) patients clinically improved after immunosuppressive therapy, some of their ECG findings did not fully recover in remission phase. In conclusion, anti-MDA5 (+) DM appears to show cardiac involvement (electrical activity and function) during the active phase. Further studies are necessary to clarify the actual cardiac condition and mechanism of these findings in patients with anti-MDA5 (+) DM. [ABSTRACT FROM AUTHOR]

Introduction: Drug-induced block of the hERG potassium channel could predispose to torsade de pointes, depending on occurrence of concomitant blocks of the calcium and/or sodium channels. Since the hERG potassium channel block affects cardiac repolarization, the aim of this study was to propose a new reliable index for non-invasive assessment of drug-induced hERG potassium channel block based on electrocardiographic T-wave features.Methods: ERD30% (early repolarization duration) and TS/A (down-going T-wave slope to T-wave amplitude ratio) features were measured in 22 healthy subjects who received, in different days, doses of dofetilide, ranolazine, verapamil and quinidine (all being hERG potassium channel blockers and the latter three being also blockers of calcium and/or sodium channels) while undergoing continuous electrocardiographic acquisition from which ERD30% and TS/A were evaluated in fifteen time points during the 24 h following drug administration ("ECG Effects of Ranolazine, Dofetilide, Verapamil, and Quinidine in Healthy Subjects" database by Physionet). A total of 1320 pairs of ERD30% and TS/A measurements, divided in training (50%) and testing (50%) datasets, were obtained. Drug-induced hERG potassium channel block was modelled by the regression equation BECG(%) = a·ERD30% + b·TS/A+ c·ERD30%·TS/A + d; BECG(%) values were compared to plasma-based measurements, BREF(%).Results: Regression coefficients values, obtained on the training dataset, were: a = -561.0 s-1, b = -9.7 s, c = 77.2 and d = 138.9. In the testing dataset, correlation coefficient between BECG(%) and BREF(%) was 0.67 (p < 10-81); estimation error was -11.5 ± 16.7%.Conclusion: BECG(%) is a reliable non-invasive index for the assessment of drug-induced hERG potassium channel block, independently from concomitant blocks of other ions. [ABSTRACT FROM AUTHOR]

Background: aVR lead is often neglected in routine clinical practice largely because of its undefined clinical utility specifications. Nevertheless, positive T-wave in aVR lead has been reported to be associated with poor clinical outcomes in some cardiovascular diseases. This study aimed to prospectively investigate the prognostic value and clinical utility of T-wave amplitude in aVR lead in patients with acute ST-elevation myocardial infarction (STEMI). Methods: A total of 340 STEMI patients admitted to a tertiary heart center were consecutively included. Patients were categorized into four strata, based on T wave amplitude in aVR lead in their admission ECG (i.e. < − 2, − 1 to − 2, − 1 to 0, and ≥ 0 mV). Patients' clinical outcomes were also recorded and statistically analyzed. Results: In-hospital mortality, re-hospitalization, and six-month-mortality significantly varied among four T wave strata and were higher in patients with a T wave amplitude of ≥ 0 mV (p 0.001–0.002). The groups of patients with higher T wave amplitude in aVR, had progressively increased relative risk (RR) of in-hospital mortality (RRs ≤ 0.01, 0.07, 1.00, 2.30 in four T wave strata, respectively). T wave amplitude in the cutoff point of − 1 mV exhibited a sensitivity and specificity of 95.83 (95% CI 78.88–99.89) and 49.68 (95% CI 44.04–55.33). Conclusion: Our study demonstrated a significant association of positive T wave in aVR lead and adverse clinical outcomes in STEMI patients. Nevertheless, the clinical utility of T-wave amplitude at aVR lead is limited by its low discriminative potential toward prognosis of STEMI. [ABSTRACT FROM AUTHOR]

Strong recent clinical evidence links the presence of prominent oscillations of ventricular repolarization in the low-frequency range (0.04-0.15 Hz) to the incidence of ventricular arrhythmia and sudden death in post-MI patients and patients with ischaemic and non-ischaemic cardiomyopathy. It has been proposed that these oscillations reflect oscillations of ventricular action potential duration at the sympathetic nerve frequency. Here we review emerging evidence to support that contention and provide insight into possible underlying mechanisms for this association. [ABSTRACT FROM AUTHOR]

BackgroundT-peak to T-end interval (Tp-e) is an independent marker of sudden cardiac death. Modulation of Tp-e by sympathetic nerve activation and circulating norepinephrine is not well understood. The purpose of this study was to characterize endocardial and epicardial dispersion of repolarization (DOR) and its effects on Tp-e with sympathetic activation.Methods and resultsIn Yorkshire pigs (n=13), a sternotomy was performed and the heart and bilateral stellate ganglia were exposed. A 56-electrode sock and 64-electrode basket catheter were placed around the epicardium and in the left ventricle (LV), respectively. Activation recovery interval, DOR, defined as variance in repolarization time, and Tp-e were assessed before and after left, right, and bilateral stellate ganglia stimulation and norepinephrine infusion. LV endocardial and epicardial activation recovery intervals significantly decreased, and LV endocardial and epicardial DOR increased during sympathetic nerve stimulation. There were no LV epicardial versus endocardial differences in activation recovery interval during sympathetic stimulation, and regional endocardial activation recovery interval patterns were similar to the epicardium. Tp-e prolonged during left (from 40.4±2.2 ms to 92.4±12.4 ms; P

Chest pain is still representing one of the most common and serious presentations to the emergency department worldwide. ECG is a crucial tool in evaluating patients with chest pain; however, only around 50% of patients with acute coronary syndrome (ACS) will have a diagnostic ECG upon their presentation; the rest may either have a completely normal ECG or what is called nonspecific ST segment and T wave (NSSTTW) changes, hence it is essential to recognize the subtle ECG changes and know its significance. One of the ECG changes that can be easily missed is when the T wave in V1 is upright, especially when it is either a Tall Upright T wave (TTV1) or a New Tall Upright T-wave (NTTV1). Although upright T wave in lead V1 can be a normal variant, it has been linked in a few studies and observations to cardiovascular disease, especially myocardial ischemia. In this article, we are trying to highlight the importance of this subtle ECG change in predicting cardiovascular disease through a concise review of the available evidence on this topic. [ABSTRACT FROM AUTHOR]

Cardiac arrhythmias are common heart diseases and generally cause sudden cardiac death. Electrocardiogram (ECG) is an effective tool that can reveal the electrical activity of the heart and diagnose cardiac arrhythmias. We propose detection of P waves based on QRST cancellation zero-one substitution. After preprocessing, the QRST segment is determined by detecting the Q wave start point and T wave end point separately. The Q wave start point is detected by digital analyses of the QRS complex width, and the T wave end point is detected by computation of an indicator related to the area covered by the T wave curve. Then, we determine whether the sampled value of the signal is in the interval of the QRST segment and substitute zero or one for the value to cancel the QRST segment. Finally, the maximum amplitude is selected as the peak of the P wave in each RR interval of the residual signal. The average detection rate for the QT database was 97.67%. [ABSTRACT FROM AUTHOR]

Background: T wave inversion in leads with ST-segment elevation after reperfusion therapy is considered a sign of reperfusion. However, the significance of T wave inversion on presentation before the initiation of reperfusion therapy is unclear. Aim of the Work: The current study aimed to assess whether the initial T wave morphology in the electrocardiographic (ECG) at presentation can predict patency of the left anterior descending artery (LAD) in patients with acute anterior ST segment elevation myocardial infarction (STEMI) before undergoing primary percutaneous coronary interventions (PCIs). Methods: This study included ninety patients who presented to the emergency department with acute anterior ST-elevation MI. We excluded patients with bundle branch block, postcoronary artery bypass grafting patients, patients with paced rhythm, and patients who received thrombolytic therapy. The T wave morphology in the 2 leads with maximal ST-segment elevation on the presenting ECG was identified as one of the three morphologies, positive T waves (T+; initial positive deflection ≥0.5 mm above the isoelectric line), biphasic T waves (T+/−; where the T wave initially showed a positive deflection above the ST segment afterward followed by a negative deflection ≥0.5 mm below the isoelectric line), and negative T waves (T−; where the T wave initially showed a negative deflection ≥0.5 mm below the isoelectric line without showing any initial positive deflection). Then, according to the results of the initial angiography, patients were classified into spontaneous reperfusion (SR) (those with thrombolysis in MI [TIMI] II or TIMI III flow in the infarct-related artery [IRA] prior to intervention) or non-SR (those with TIMI 0 or TIMI I flow in the IRA prior to intervention). Results: Ninety consecutive patients (77 males and 13 females) presented by STEMI and treated by primary PCI at cath lab of Ainshams University Hospitals (a 24/7 tertiary referral center for primary PCI) between January 2015 and March 2016 were included in this study, of which 40 patients (44.4%) had positive T waves (T+), 34 patients (37.8%) had negative T waves (T−), and 16 patients (17.8%) had biphasic T waves (T+/−). Initial angiogram showed that 18 patients had SR and 72 patients had no SR. With regard to T wave morphology, negative T waves were significantly present in SR group (66.7% vs. 30.6%, P = 0.004), whereas positive T waves were predominantly present in non-SR (50% vs. 22.2%, P = 0.033). Conclusions: For SR of LAD in anterior STEMI patients, prior to primary PCI, T wave inversion had a good sensitivity of 66.7%, a specificity of 69.4%, and a good negative predictive value of 89.29%.

Irregular heartbeat results in heart diseases. Cardiac deaths are most seen across the globe. Detecting the heart problems in early stage can reduce the death rate. Electrocardiogram (ECG) is one of the most popular method for diagnosing different arrhythmias. Arrhythmia means irregular activity of heart or abnormal heart rhythm. In this paper, cardiac signal peaks P-wave, QRS complex and T-wave are detected for classifying the type of arrhythmia. These are the main components of ECG signal. P-wave is of very small duration, it is ex-plains about the atrial depolarization. The QRS complex may include combination of Q-wave, R-wave, and S-wave. But every QRS complex may not contain Q-R-S waves. It explains about ventricular depolarization. Whereas T wave is about ventricular re-polarization. S-Golay filter is used for denoising. This is used for smoothing the data which thereby, increases the precision of data without distortion of signal tendency. The patient data is collected from MIT-BIH Arrhythmia database for analysis. The simulation is done in Matlab software. [ABSTRACT FROM AUTHOR]

Background: Inverted T waves in the electrocardiogram (ECG) have been associated with coronary heart disease (CHD) and mortality. The pathophysiology and prognostic significance of T‐wave inversion may differ between different anatomical lead groups, but scientific data related to this issue is scarce. Methods: A representative sample of Finnish subjects (n = 6,354) aged over 30 years underwent a health examination including a 12‐lead ECG in the Health 2000 survey. ECGs with T‐wave inversions were divided into three anatomical lead groups (anterior, lateral, and inferior) and were compared to ECGs with no pathological T‐wave inversions in multivariable‐adjusted Fine–Gray and Cox regression hazard models using CHD and mortality as endpoints. Results: The follow‐up for both CHD and mortality lasted approximately fifteen years (median value with interquartile ranges between 14.9 and 15.3). In multivariate‐adjusted models, anterior and lateral (but not inferior) T‐wave inversions associated with increased risk of CHD (HR: 2.37 [95% confidence interval 1.20–4.68] and 1.65 [1.27–2.15], respectively). In multivariable analyses, only lateral T‐wave inversions associated with increased risk of mortality in the entire study population (HR 1.51 [1.26–1.81]) as well as among individuals with no CHD at baseline (HR 1.59 [1.29–1.96]). Conclusions: The prognostic information of inverted T waves differs between anatomical lead groups. T‐wave inversion in the anterior and lateral lead groups is independently associated with the risk of CHD, and lateral T‐wave inversion is also associated with increased risk of mortality. Inverted T wave in the inferior lead group proved to be a benign phenomenon. [ABSTRACT FROM AUTHOR]

Electrocardiography (ECG) remains an irreplaceable tool in the management of the patients with myocardial infarction, with evaluation of the QRS and ST segment being the present major focus. Several ECG parameters have already been proposed to have prognostic value with regard to both in-hospital and long-term follow-up of patients. In this review, we discuss various ECG parameters other than ST segment changes, particularly with regard to their in-hospital prognostic importance. Our review not only evaluates the prognostic segments and parts of ECG, but also highlights the need for an integrative approach in big data to re-assess the parameters reported to predict in-hospital prognosis. The evolving importance of artificial intelligence in evaluation of ECG, particularly with regard to predicting prognosis, and the potential integration with other patient characteristics to predict prognosis, are discussed. [ABSTRACT FROM AUTHOR]

Background: Positive T wave in lead aVR (TaVR) has been associated with increased risk of adverse events in patients with various cardiovascular diseases.Objective: The purpose of this study was to investigate the prevalence and prognostic significance of positive TaVR in patients with hypertrophic cardiomyopathy (HCM).Methods: This study investigated 421 consecutive patients with HCM (177 women; age 51.1 ± 14.9 years). Admission electrocardiogram was examined for the presence of a positive TaVR. The primary endpoint was defined as a composite of major arrhythmic events (MAEs), which included sudden cardiac death, sustained ventricular tachycardia or fibrillation, or appropriate implantable cardioverter-defibrillator therapy. Cardiovascular mortality and all-cause death were evaluated as secondary endpoints.Results: During median follow-up period of 6.0 years (interquartile range 4.0-11.6 years), 53 patients (12.6%) experienced the primary endpoint. On multivariable competing analysis, after adjusting for other confounding factors, the presence of positive TaVR was found to be an independent and strong predictor of the primary composite endpoint. Time-dependent receiver operating characteristic analysis, net reclassification index, and integrated discrimination improvement showed that the addition of positive TaVR to conventional HCM risk factors improved prediction of arrhythmic events. However, in subgroup analysis, a positive TaVR lost statistical significance in patients with apical HCM but remained significant in patients with all other hypertrophy patterns.Conclusion: Positive TaVR is associated with MAE in HCM patients, independent of and incremental to traditional risk factors. [ABSTRACT FROM AUTHOR]

Fetal heart rate (FHR) variability (FHRV) and ST segment morphology are potential clinical indices of fetal well-being during labor. -Adrenergic stimulation by circulating catecholamines has been hypothesized to contribute to both FHRV and ST segment morphology during labor, but this has not been tested during brief repeated fetal hypoxemia that is characteristic of labor. Near-term fetal sheep (0.85 gestation) received propranolol (-adrenergic blockade; n =10) or saline (n= 7) 30 min before being exposed to three 2-min complete umbilical cord occlusions (UCOs) separated by 3-min reperfusions. T/QRS ratio was calculated throughout UCOs and reperfusion periods, and measures of FHRV (RMSSD, SDNN, and STV) were calculated between UCOs. During the baseline period, before the start of UCOs, propranolol was associated with reduced FHR, SDNN, and STV but did not affect RMSSD or T/QRS ratio. UCOs were associated with rapid FHR decelerations and increased T/QRS ratio; propranolol significantly reduced FHR during UCOs and was associated with a slower rise in T/QRS ratio during the first UCOs, without affecting the maximal rise or T/QRS ratio during the second and third UCO. Between UCOs propranolol reduced FHR and T/QRS ratio but did not affect any measure of FHRV. These data demonstrate that circulating catecholamines do not contribute to FHRV during labor-like hypoxemia. Furthermore, circulating catecholamines did not contribute to the major rise in T/QRS ratio during labor-like hypoxemia but may regulate T/QRS ratio between brief hypoxemia. [ABSTRACT FROM AUTHOR]

Background: Noncompaction cardiomyopathy (NCCM) is a relatively rare cardiac abnormality with high rates of mortality and morbidity. T-wave amplitudes during ventricular repolarization in lead aVR (TaVR) have been reported to be associated with the prognosis of various cardiovascular diseases. This study sought to investigate the prevalence and prognostic role of positive TaVR in patients with NCCM.Methods: We evaluated consecutive 161 patients with NCCM (65.8% men, mean age 42.5 ± 15.2 years old). Presentation electrocardiogram was assessed regarding classical parameters as well as T-wave amplitudes in lead aVR. The primary endpoint was defined as composite lethal arrhythmic events, including sudden cardiac death, ventricular fibrillation, or sustained ventricular tachycardia or appropriate implantable cardioverter-defibrillator shock. Heart failure requiring hospitalization, cardiovascular death, and all-cause mortality were also investigated as secondary endpoints.Results: Patients with positive TaVR showed higher rates for arrhythmic events, hospitalization for heart failure, and death compared with patients without it. In multivariate Cox model, after adjusting for other known clinical and electrocardiographic risk factors, the positive TaVR was found to be a strong independent predictor of primary endpoint (HR: 4.8, 95% CI: 1.2-19.3; p = .025) and all-cause death (HR: 3.5, 95% CI: 1.0-12.1; p = .045).Conclusion: Our findings revealed that positive TaVR is significantly and independently associated with adverse outcomes in NCCM patients. This unique ECG criterion in the often ignored lead provides incremental information beyond what is available with other traditional risk factors. [ABSTRACT FROM AUTHOR]

The electrocardiogram (ECG) morphology determines the overall activity of the heart and is the most widely used tool in the diagnostic processes. T wave is a crucial wave component that reveals very useful information regarding various cardiac disorders. In this paper we have proposed a novel T wave detection technique based on adaptive window and simple decision rule. The proposed technique uses two-stage median filters followed by the Savitzky-Golay filter at the pre-processing stage to remove the noises in the ECG signal. The QRS complex is detected for locating the T wave as a reference in one ECG cycle. An R-R interval based window is considered for detecting the T wave, and decision logic depends on the iso-electric line value. The proposed technique is tested on the QT database and self-recorded dataset for its performance evaluation. In the present work, the results achieved for T wave detection sensitivity (Se), positive predictivity (+P), detection error rate (DER), and accuracy (Acc) on the QT database are Se = 97.57%, +P = 99.63%, DER = 2.78%, and Acc = 97.22% with an average time error of (3.468 ± 5.732) ms. The proposed technique shows Se = 99.94%, +P = 99.94%, DER = 0.01%, and Acc = 99.89% on the self-recorded dataset. The proposed technique is also capable of detecting both the upward and downward T wave efficiently in the ECG signal. [ABSTRACT FROM AUTHOR]