Relationship of the T-wave Tpeak-Tend interval with conduction system disorders in arterial hypertension / Relación del intervalo Tpico-Tfinal de la onda T con trastornos del sistema de conducción en hipertensión arterial

Abstract 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.

Resumen Objetivo: El intervalo Tpico-Tfinal de la onda T es un marcador electrocardiográfico de la dispersión transmural aumentada de la repolarización ventricular. Investigamos la presencia de trastornos del sistema de conducción cardíaca en pacientes con hipertensión arterial sistémica (HA) que poseen alterado el intervalo Tpico-Tfinal de la onda T. Métodos: Los 67 pacientes con HA fueron divididos en dos grupos. Aquellos con intervalos de Tpico-Tfinal prolongados (≥ 77 ms), 21 (31%) pacientes (grupo de estudio). Aquellos con intervalos normales (< 77 ms) Tpico-Tfinal, 46 (69%) pacientes (grupo control). Los intervalos Tpico-Tfinal fueron medidos por herramientas de análisis electrocardiográfico computarizado. Resultados: El valor mediano de la duración del complejo QRS fue significativamente más amplio en el grupo de estudio (110 ± 12 ms vs. 94 ± 8 ms p < 0.001). Hubo una incidencia significativamente mayor de hemibloqueo anterior izquierdo en el grupo de estudio (14% vs. 0% p < 0.04). El valor mediano del intervalo QTc fue significativamente mayor en el grupo de estudio (440 ± 26 vs. 422 ± 15 p < 0.01). Hubo una incidencia significativamente mayor de pacientes con intervalo QTc prolongado en el grupo de estudio (33% vs. 11% p < 0.02). El valor mediano del intervalo Tpico-Tfinal fue significativamente mayor en el grupo de estudio (84 ± 5 ms vs. 65 ± 4 ms p < 0.001), así como el cociente Tpico-Tfinal/QTc (0.19 ± 0.1 vs. 0.16 ± 0.1 p < 0.001). Conclusión: Existe una alteración de la repolarización ventricular significativamente mayor y anomalías del sistema de conducción cardíaca en pacientes con HA que poseen alteración del intervalo Tpico-Tfinal de la onda T.

Giant fibroma of left ventricular apex with T wave inversion: 2 cases report and literature review / 中国综合临床

Objective:To investigate the clinical features, diagnostic methods and treatments of left ventricular apical fibroma.Methods:The clinical manifestations, ECG, imaging features and treatment plans of 2 patients with giant fibroma of left ventricular apex diagnosed in September 2020 and May 2022 were analyzed retrospectively, and the related literature was reviewed.Results:Both patients had slight chest distress and discomfort after activities. The ECG showed T-wave inversion of different degrees, which were misdiagnosed as “myocarditis” and “coronary heart disease” respectively. The cardiac magnetic resonance imaging and echocardiography showed left ventricular apical mass. Coronary artery stenosis was not found in coronary angiography. One patient required conservative treatment, and there was no significant change in clinical symptoms and tumor size in the follow-up for half a year; Another patient underwent cardiac mass removal, and the pathological examination after operation confirmed that it was cardiac fibroma, and there was no recurrence in the follow-up 2 years.Conclusion:Fibroma of left ventricular apex is a rare cardiac tumor, which is easy to be missed and misdiagnosed, and is one of the rare causes of T-wave inversion. Cardiac magnetic resonance imaging, CT and echocardiography are commonly used imaging methods to diagnose cardiac fibroma, and surgical resection is an effective treatment.

12-lead electrocardiogram for orthostatic hypertension in children and its clinical significance / 中国基层医药

Objective:To investigate the 12-lead electrocardiogram findings and their clinical significance in children with orthostatic hypertension (OHT), providing evidence for clinical diagnosis and treatment of OTH.Methods:Thirty-four children with OHT who received diagnosis and treatment in the Zhuji Second People's Hospital from January 2017 to December 2019 were included in the OHT group. An additional 34 healthy children who concurrently received routine physical examination were included in the control group. Both groups of children underwent a 12-lead electrocardiogram in lying and standing positions. The changes in ST-segment and T-wave amplitudes in the lying position relative to the standing position were compared between the two groups.Results:The changes in T-wave amplitude of leads II, V 5, and V 6 in the OHT group were (0.07 ± 0.11) mV, (0.13 ± 0.12) mV, and (0.14 ± 0.11) mV, respectively, which were significantly higher than those in the control group [(0.02 ± 0.07) mV, (0.05 ± 0.06) mV, (0.03 ± 0.04) mV, t = 2.24, 3.48, 5.48, P = 0.029, 0.001, < 0.001). There were no significant differences in the changes in T-wave amplitude of other leads between the two groups (all P > 0.05). There was no significant difference in change in ST-segment amplitude on 12-lead electrocardiogram images between the two groups (all P > 0.05). The area under the curve of the changes in T-wave amplitude of leads II and V 5 in predicting OHT in children was 0.596 and 0.672 respectively, the sensitivity was 64.71% and 55.88%, respectively, and the specificity was 70.59% and 61.76%, respectively. The changes in T-wave amplitude of leads II and V 5 had low efficacy in predicting OHT in children. The area under the curve of the change in T-wave amplitude of lead V 6 in predicting OHT in children was 0.738, and the sensitivity and specificity were 76.47% and 67.65%, respectively. The change in T-wave amplitude of lead V 6 had moderate efficacy for predicting OHT in children. Conclusion:The changes in T-wave amplitude of lead V 6 on the electrocardiogram image taken in the lying position relative to the standing position are of certain value in predicting OHT in children. The 12-lead electrocardiogram can provide important evidence for clinical prediction and diagnosis of OHT in children.

Significance of Abnormal T Waves in Acute Coronary Syndrome without ST Changes in ECG

T-wave abnormalities are common electrocardiographic occurrences in patients with acute coronary syndromes. The clinical and electrocardiographic course and angiographic findings in patients with evolving inverted or biphasic T waves have not been fully elucidated. Patients with abnormal T waves associated with unstable angina represent a subgroup with a high probability of near total obstruction of coronary artery and myocardial dysfunction. In the present study we describe a subgroup of patients with myocardial ischemia who during the acute Ischemic phase did not develop elevation but only biphasic or inverted T waves in the ECG and had >90% stenosis of 1 or more coronary arteries. Methods: The study comprised 125 patients presented with unstable angina pectoris. Patients’ characteristics, Electrocardiographic Data, Cardiac enzymes and Coronary angiography findings were obtained. Collected data was analyzed and sensitivity, specificity, positive predictive value, significance of test (p value) were calculated using appropriate statistical method. Results: Of the 125 patients deep symmetrical and sustained T-wave inversions were present in 72 patients & biphasic T-waves in 28 patients. 125 patients underwent coronary angiography, 92(74%) patients had >90% stenosis of 1 or more coronary arteries; sensitivity of abnormal T waves for significant stenosis was 90%, specificity 92%, positive predictive value 97.83 % and p value <0.001. Conclusion: We have identified a subgroup of patients with critical obstruction of coronary artery in patients with unstable angina and non diagnostic ECG T-wave abnormalities are significant electrocardiographic occurrences in patients with acute coronary syndromes and frequently associated with coronary artery obstruction

Sedative and electrocardiographic effects of low dose dexmedetomidine in healthy cats / Efeitos sedativos e eletrocardiográficos da baixa dose de dexmedetomidina em gatos saudáveis

In feline veterinary practice sedation is often needed to perform diagnostic or minimally invasive procedures, minimize stress, and facilitate handling. The mortality rate of cats undergoing sedation is significantly higher than dogs, so it is fundamental that the sedatives provide good cardiovascular stability. Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist utilized in cats to provide sedation and analgesia, although studies have been utilized high doses, and markedly hemodynamic impairments were reported. The aim of this study was to prospectively investigate how the sedative and electrocardiographic effects of a low dose of DEX performing in cats. Eleven healthy cats were recruited; baseline sedative score, systolic arterial pressure, electrocardiography, and vasovagal tonus index (VVTI) were assessed, and repeated after ten minutes of DEX 5μg/kg intramuscularly (IM). A smooth sedation was noticed, and emesis and sialorrhea were common adverse effects, observed on average seven minutes after IM injection. Furthermore, electrocardiographic effects of a low dose of DEX mainly include decreases on heart rate, and increases on T-wave amplitude. The augmentation on VVTI and appearance of respiratory sinus arrhythmia, as well as sinus bradycardia in some cats, suggesting that DEX enhances parasympathetic tonus in healthy cats, and therefore will be best avoid in patients at risk for bradycardia.(AU)

Na rotina clínica da medicina veterinária felina a sedação é frequentemente requerida para realização de procedimentos diagnósticos ou minimamente invasivos, para minimizar o estresse e facilitar o manuseio dos pacientes. A taxa de mortalidade de gatos submetidos à sedação é mais elevada do que em cães, por esse motivo, é fundamental que os sedativos confiram estabilidade hemodinâmica. A dexmedetomidina (DEX) é um α2-agonista utilizado em felinos para promover sedação e analgesia, porém os estudos têm utilizado doses elevadas, e com isso prejuízos hemodinâmicos importantes foram relatados. O objetivo desta investigação foi avaliar os efeitos sedativos e eletrocardiográficos da baixa dose de DEX em gatos. Para tal, onze felinos saudáveis foram recrutados, foram obtidos valores basais para escore de sedação, pressão arterial sistólica e eletrocardiografia, além do índice de tônus vaso vagal (ITVV). Após dez minutos da aplicação intramuscular (IM) de DEX 5μg/kg todos os exames foram repetidos. Após a DEX, sedação suave foi detectada, e a êmese e sialorreia foram efeitos adversos comuns, observados em média 7 minutos após a injeção IM. Ademais, os principais efeitos eletrocardiográficos foram redução na frequência cardíaca e aumento na amplitude da onda T. O ITVV mais elevado e surgimento de arritmia sinusal respiratória, bem como bradicardia sinusal em alguns gatos, sugerem que a DEX eleva o tônus parassimpático, e por esse motivo deve ser utilizada com cautela em pacientes com predisposição à bradicardia.(AU)

Influence of percutaneous coronary intervention on T-wave peak-end interval in coronary heart disease patients and its warning value on sudden cardiac death / 中国基层医药

Objective@#To investigate the influence of percutaneous coronary intervention on T-wave peak-to-interval and its value of early warning of sudden cardiac death in patients with coronary artery disease.@*Methods@#From January 2013 to December 2014, 90 patients with coronary heart disease who underwent percutaneous coronary intervention in the Second Affiliated Hospital of Zhejiang University of Traditional Chinese Medicine were selected as observation group.And at the same time, 90 patients with normal coronary angiography in our hospital were selected as control group.Tp-Te (T-wave peak to end-time limit in ECG) and Tp-Te/QT (Tp-Te) were compared between the observation group and the control group.The ratio of the period to the QT interval, Tp-Te/ (heart rate corrected T-peak period), Tp-Te, Tp-Te/QT, Tp-Te/ before and after treatment in the observation group, and treatment Tp-Te, Tp-Te/QT, Tp-Te/ in the group with and without ventricular arrhythmia and sudden cardiac death were observed.@*Results@#Before treatment, the Tp-Te[(116.47±26.81)ms], Tp-Te/QT[(0.29±0.06)] and Tp-Te/[(131.78±36.23)ms] in the observation group were higher than those in the control group -Te(78.69±22.73)ms, Tp-Te/QT (0.21±0.04), Tp-Te/ (100.49±32.96)ms] (t=10.197, 10.525, 6.061, all P<0.05). After treatment, the Tp-Te[(94.78±11.34)ms], Tp-Te/QT[(0.24±0.04)], Tp-Te/[(108.62±20.18)ms] in the observation group were lower than those before treatment (t=7.069, 6.558, 5.298, all P<0.05). At 6 months after operation, the Tp-Te and Tp-Te/ were significantly lower than postoperative 24h[(99.89±21.64)ms, (117.35±32.47)ms](t=1.984, 2.166, all P<0.05). After treatment, the Tp-Te[(118.87±30.92)ms], Tp-Te/QT [(0.29±0.08)], and Tp-Te/[(135.73±37.29)ms] in ventricular arrhythmia patients with sudden cardiac death were higher than those without sudden cardiac death[(95.13±26.38)ms, (0.25±0.06), (106.36±30.14)ms] (t=3.012, 2.171, 3.226, all P<0.05).@*Conclusion@#T-Te, Tp-Te/QT, Tp-Te/ T-peak peak-to-interphase indicators can be used to predict the degree of coronary artery ischemia and disease, but also for cardiovascular diseases such as ventricular arrhythmias and sudden cardiac death.The index adverse events play a certain role in early warning and have clinical research value.

Microvolt T-wave alternans complemented with electrophysiologic study for prediction of ventricular tachyarrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy: a long-term follow-up study / 中华医学杂志(英文版)

Background@#The long-term predicted value of microvolt T-wave alternans (MTWA) for ventricular tachyarrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) remains unclear. Our study explored the characteristics of MTWA and its prognostic value when combined with an electrophysiologic study (EPS) in patients with ARVC.@*Methods@#All patients underwent non-invasive MTWA examination with modified moving average (MMA) analysis and an EPS. A positive event was defined as the first occurrence of sudden cardiac death, documented sustained ventricular tachycardia (VT), ventricular fibrillation, or the administration of appropriate implantable cardioverter defibrillator therapy including shock or antitachycardia pacing.@*Results@#Thirty-five patients with ARVC (age 38.6 ± 11.0 years; 28 males) with preserved left ventricular (LV) function were recruited. The maximal TWA value (MaxValt) was 17.0 (11.0–27.0) μV. Sustained VT was induced in 22 patients by the EPS. During a median follow-up of 99.9 ± 7.7 months, 15 patients had positive clinical events. When inducible VT was combined with the MaxValt, the area under the curve improved from 0.739 to 0.797. The receiver operating characteristic curve showed that a MaxValt of 23.5 μV was the optimal cutoff value to identify positive events. The multivariate Cox regression model for survival showed that MTWA (MaxValt, hazard ratio [HR], 1.06; 95% confidence interval [CI], 1.01–1.11; P = 0.01) and inducible VT (HR, 5.98; 95% CI, 1.33–26.8; P = 0.01) independently predicted positive events in patients with ARVC.@*Conclusions@#MTWA assessment with MMA analysis complemented by an EPS might provide improved prognostic ability in patients with ARVC with preserved LV function during long-term follow-up.

Influence of percutaneous coronary intervention on T－wave peak－end interval in coronary heart disease patients and its warning value on sudden cardiac death / 中国基层医药

Objective To investigate the influence of percutaneous coronary intervention on T －wave peak－to－interval and its value of early warning of sudden cardiac death in patients with coronary artery disease .Methods From January 2013 to December 2014,90 patients with coronary heart disease who underwent percutaneous coronary intervention in the Second Affiliated Hospital of Zhejiang University of Traditional Chinese Medicine were selected as observation group.And at the same time,90 patients with normal coronary angiography in our hospital were selected as control group.Tp－Te ( T－wave peak to end －time limit in ECG) and Tp －Te／QT ( Tp －Te) were compared between the observation group and the control group.The ratio of the period to the QT interval ,Tp－Te／(heart rate corrected T－peak period),Tp－Te,Tp－Te／QT,Tp－Te／ before and after treatment in the observation group,and treatment Tp－Te,Tp－Te／QT,Tp－Te／ in the group with and without ventricular arrhythmia and sudden cardiac death were observed.Results Before treatment,the Tp－Te[(116.47 ±26.81) ms],Tp－Te／QT [(0.29 ±0.06)] and Tp－Te／[(131.78 ±36.23)ms] in the observation group were higher than those in the control group [Tp－Te(78.69 ±22.73) ms,Tp－Te／QT (0.21 ±0.04),Tp－Te／ (100.49 ±32.96) ms] ( t＝10.197,10.525,6.061, all P ＜0.05).After treatment,the Tp －Te [(94.78 ±11.34) ms], Tp －Te／QT [(0.24 ±0.04)],Tp－Te／[(108.62 ±20.18) ms] in the observation group were lower than those before treatment (t＝7.069,6.558,5.298,all P＜0.05).At 6 months after operation,the Tp－Te and Tp－Te／ were significantly lower than postoperative 24h[(99.89 ±21.64) ms,(117.35 ±32.47) ms] (t＝1.984,2.166,all P＜0.05).After treatment,the Tp－Te[(118.87 ±30.92) ms],Tp－Te／QT [(0.29 ±0.08)],and Tp －Te／ [(135.73 ±37.29)ms] in ventricular arrhythmia patients with sudden cardiac death were higher than those without sudden cardiac death [(95.13 ±26.38)ms,(0.25 ±0.06),(106.36 ±30.14) ms] ( t＝3.012,2.171,3.226,all P＜0.05).Conclusion T－Te,Tp－Te／QT,Tp－Te／ T－peak peak－to－interphase indicators can be used to predict the degree of coronary artery ischemia and disease ,but also for cardiovascular diseases such as ventricular arrhythmias and sudden cardiac death.The index adverse events play a certain role in early warning and have clinical research value.

Early T-wave inversion in anterior leads predict patency of the anterior descending artery in ST-segment elevation myocardial infarction / La onda T invertida temprana en derivaciones anteriores predice permeabilidad de la arteria descendente anterior en infarto agudo de miocardio con elevación del segmento ST

Abstract: Introduction: T-wave inversion has always been considered as a natural progression sign of the non-perfunded myocardial infarction, however it is also seen after early succesful reperfusion via fibrinolysis or primary angioplasty; its role in predicting auto-reperfusion has not been established. Objective: Assess the patency of the infarct-related artery (IRA) in patients presenting with early (< 3 hours of symptoms onset) T-wave inversion (TWI) in leads with ST-segment elevation (STE) myocardial infarction (STEMI). Methods: We retrospectively analyzed 432 patients admitted at the emergency department of the National Cardiology Institute in Mexico City with a diagnosis of STEMI who arrived within three hours of symptoms onset and underwent primary percutaneous coronary intervention (p-PCI) from October 2005 to November 2015. Clinical data, electrocardiogram (ECG) and angiographic data were reviewed. The subjects were divided in two groups: those with TWI and those with positive T waves (PTW). Results: 386 (89.3%) patients presented with PTW and 46 (10.6%) with TWI. The presence of early TWI in anterior leads predicted patency of the anterior descending artery (LAD) (18 [69.2%] vs 41 [24%]; p < 0.001) but not in other arteries. Conclusions: The presence of early TWI in anterior leads with STE is associated with patency of the LAD. This relationship was not found in other infarct-related arteries.(AU)

Resumen: Introducción: La onda T invertida siempre se ha considerado como progresión natural de un infarto de miocardio no reperfundido, sin embargo, también se puede observar posterior a fibrinólisis o angioplastia primaria exitosas, su rol en predecir autorreperfusión no ha sido establecido. Objetivo: Valorar la permeabilidad de la arteria culpable del infarto (ACI) en pacientes que se presentan con onda T invertida (OTI) temprana (menos de tres horas de inicio de síntomas) en derivaciones con elevación del segmento ST (IAMCEST). Métodos: Se analizaron 432 pacientes de forma retrospectiva que fueron admitidos al Servicio de Urgencias del Instituto Nacional de Cardiología en la Ciudad de México con diagnóstico de IAMCEST dentro de las primeras tres horas de inicio de los síntomas y que fueran llevados a angioplastia primaria de octubre de 2005 a noviembre de 2015. Se revisaron datos clínicos, electrocardiogramas y angiografías coronarias. Los sujetos fueron divididos en dos grupos: aquéllos con OTI y aquéllos con onda T positiva (OTP). Resultados: Se presentaron 386 (89.3%) pacientes con OTP y 46 (10.6%) con OTI. La presencia de OTI temprana en derivaciones anteriores predijo permeabilidad de la descendente anterior (DA) (18 [69.2%] vs 41 [24%]; p < 0.001) pero no en las otras arterias. Conclusión: La presencia de OTI tempranas en derivaciones anteriores con elevación del segmento ST se asocia a permeabilidad de la DA. Este hallazgo no fue encontrado en otras arterias culpables de infarto.(AU)

Distribution Features of Microvolt T-wave Alternation in Coronary Artery Disease Patients With MTWA Changes After Revascularization / 中国循环杂志

Objective: To explore the distribution features of microvolt T-wave alternation(MTWA) through exercise stress test (EST) in coronary artery disease (CAD) patients with MTWA changes after revascularization. Methods: MTWA was measured in pre-cordial ECG leads in 326 patients with suspected CAD. Based on coronary angiography and coronary CTA, the patients were divided into 4 groups: ① Control group, patients without coronary stenosis, n=101, ② Coronary stenosis<50％ group, n=99, ③ 50％ ≤ Coronary stenosis<70％ group, n=53 and ④ Coronary stenosis ≥ 70％ group, n=73; MTWA was compared among different groups. 95 patients with coronary stenosis ≥ 50％were further divided into 2 subgroups: R (right coronary)stenosis ≥ 50％ subgroup, n=23 and LAD (left anterior descending branch) stenosis ≥ 50％ subgroup, n=72; MTWA was respectively compared to Control group. In addition, MTWA was collected from 103 patients with percutaneous coronary intervention (PCI) as PCI group, MTWA was compared to Coronary stenosis ≥ 70％ group. Results: MTWA was obviously higher in Coronary stenosis ≥ 70％ group than the other 3 groups, all P<0.01. Compared with Control group, Rstenosis ≥ 50％ subgroup had increased MTWA in V4-V6 pre-cordial leads, P<0.05; LAD stenosis≥50％ subgroup had increased MTWA in V1-V2 pre-cordial leads, P<0.01. Compared with Coronary stenosis ≥ 70％group, PCI group showed reduced MTWA, P<0.01. Conclusion: CAD patients with severe coronary stenosis (≥70％) had increased MTWA; MTWA distribution in body surface was approximately corresponding to coronary stenosis site and PCI may decrease MTWA in CAD patients.

Can you interpret the ECG under stress?

Stress (Takotsubo) cardiomyopathy (SC) is a cardiomyopathy characterised by transient myocardial dysfunction, commonly triggered by a surge in catecholamine. Electrocardiographic features may mimic other conditions, such as myocardial infarction. We presented two cases of SC and reviewed the electrocardiographic features of this disease entity.

Distorsión morfológica isquémica de la onda T en la centellografía de perfusión miocárdica con estrés vasodilatador / Ischemic T wave distortion associated with vasodilator-stress myocardial perfusion imaging

Los protocolos que utilizan vasodilatadores para inducir isquemia en la centellografía de perfusión miocárdica han demostrado una exactitud diagnóstica elevada e incidencia muy baja de complicaciones graves. Sin embargo, el significado fisiológico y valor diagnóstico de diversas alteraciones electrocardiográficas asociadas al estrés vasodilatador ha sido escasamente evaluado más allá del segmento ST. Describimos cinco pacientes que presentan distorsión morfológica de la onda T en derivaciones electrocardiográficas torácicas asociada a diversos defectos de perfusión, discutiendo los potenciales aportes de estos cambios al diagnóstico y cuantificación de la isquemia miocárdica en los estudios de imagen que utilizan estrés con vasodilatadores.

The protocols using vasodilators to induce ischemia on myocardial perfusion scintigraphy have shown a high diagnostic accuracy and a very low incidence of serious complications. However, the physiological significance and diagnostic value of various electrocardiographic changes associated with vasodilator stress has not been deeply evaluated beyond the ST-segment. Five clinical cases presenting morphological distortion of the T-wave in electrocardiographic chest leads associated with varying degrees of perfusion defects are described, discussing potential contributions of these changes to the diagnosis and quantification of myocardial ischemia in imaging studies using vasodilator stress.

T wave

The T wave in a surface electrocardiogram (ECG) indicates the diastolic phase in the cardiac cycle. Even though the cellular basis of T-wave morphology in surface ECG remains unclear in clinical cardiology, the morphology may be determined by the transmural voltage gradient during the repolarization period that underlies the changes in the T wave and QT interval. The heterogeneous distribution of electrophysiological activity across the heart is essential for normal cardiac function. However, excessive heterogeneity may contribute to arrhythmogenesis and sudden cardiac death. This paper will provide an overview of T wave genesis and the contribution to action potential duration (APD), in which ion channels are involved in the repolarization period, with special emphasis on K+ channels involved in phase 3 repolarization. These channels are primarily Kv11.1 (hERG1), Kv7.1 (KCNQ1), and Kir2.1 (KCNJ2), which are the α-subunits responsible for conducting I(Kr), I(Ks), and I(K1). Changes in the T wave and QT interval that are affected by both functional loss and gain of these currents are associated with various arrhythmogenic diseases. This review also briefly discusses arrhythmogenesis in diseases that are manifested by changes in the T wave and QT interval.

The assessment of cardiovascular function in obesity children / 临床儿科杂志

ObjectivesTo assess the cardiovascular function in obese children.MethodsA total of 30 obese children and 50 age- and sex-matched normal weight children were enrolled and treadmill test was performed. Exercise tolerance, the time to target heart rate and continuous T-wave alternans (TWA) during treadmill test were compared between two groups. ResultsCompared with normal weight children, the exercise tolerance was decreased and the time to target heart rate was shortened, while the incidence of continuous TWA was increased in obese children and there was signiifcant difference between two groups (P<0.01).ConclusionsObesity may lead to cardiovascular dysfunction in childhood which should be concerned.

The normal variations in heart rate and QRS complex of healthy individuals in different age groups.

Background: Electrocardiography is the only practical method of recording the electrical behavior of the heart. It is often an independent marker of myocardial disease and occasionally the only indication of the pathologic process. Therefore the present study has been undertaken to find out the degree of normal variations in healthy individuals in different age groups. Methods: This study was conducted after the institutional ethical clearance and informed written consent from all the subjects belongs to age group of 18 to 40 years of either sex. All the ECG was taken in resting and supine position using BPL CARDIART 308 machine. The body weight, the QRS duration, QRS axis, P wave duration, P wave voltage, P wave axis in the frontal plane, QTc interval, T wave voltage and QRS-T angle was calculated. The values are expressed as mean and the percentile was calculated in each parameters. Results: The weight ranges from 56.37 ± 6.53 kg. QRS duration ranged from 0.04 to 0.12 seconds mean of 0.064 seconds. QRS voltage in V6 varied from 0.30 to 2.1 mv with a mean of 1.14 mv. The QTc interval was 0.31 to 0.47 seconds mean was 0.39 seconds. QRS-T angle varied from 0° to 70° with a mean of 30.9°. Conclusion: The study provides the frequency distribution and other statistical data when applied to all components of ECG which are commonly assessed during investigations of healthy young individuals. Having knowledge of these normal variants will be helpful in arriving at correct diagnosis.

The characteristics of T wave alternans in aortic stenosis in school-aged children / 临床儿科杂志

Objective To explore the characteristics of T wave alternans (TWA) in aortic stenosis (AS) in school-aged children. Methods TWA was analyzed in 15 AS patients and 60 age-matched normal children using Microvolt T-Wave Alternans and the incidence of sustained TWA was compared between two groups. Myocardial ischemia during treadmill test was studied in sustained TWA and non-sustained TWA in AS patients. Results Compared with normal children, the incidence of sustained TWA was signiifcantly increased in AS group (P<0.01). In AS school-aged patients, the incidence of myocardial ischemia is higher in sustained TWA than in non-sustained TWA during treadmill test (P<0.05). Conclusions AS school-aged children have electrophysiologic basis for sunstained TWA. TWA is closely related to myocardial ischemia during treadmill test. Sustained TWA could be used as an important electrophysiologic index to assess the cardiac function in children with AS.

Assessment of the age range, where juvenile T inversion pattern in right precordial leads of an ECG changes to the adult upright T wave pattern.

Objective: To determine the age range, where juvenile T inversion pattern in right precordial leads (V1 to V4) in an ECG changes to the adult upright T wave pattern Method: A descriptive cross-sectional study was done in children aged 5 years and above referred to the paediatric cardiology clinic, Teaching Hospital Karapitiya from January 2012 to April 2013. Inclusion criteria were: children with no cardiac lesion or a haemodynamically insignificant cardiac lesion after a full cardiac evaluation.The cohort was divided into six age groups and the presence of juvenile and adult ECG patterns were evaluated. Results: A total number of 1039 children were enrolled. At the age of 13 years 50% depicted both juvenile and adult ECG patterns. At the age range of 13-15 years 78 (60%) of a total of 130 showed the adult ECG pattern compared to 99 (44.4%) of a total of 223 at 11-13 years (X2=8.0; p=0.005). Even after 13 years of age the juvenile ECG pattern persisted in 30-40% of children. Conclusions: Transition of the juvenile T inversion pattern in right precordial leads in an ECG to the adult upright T wave pattern occurs predominantly at the age range of 13-15 years. Presence of juvenile T inversion pattern in an ECG after 13-15 years can be a normal finding as well as may be a pre-symptomatic diagnosis of a cardiomyopathy. Although it is normal to have a juvenile ECG pattern above 13 years it is advisable to perform an echocardiographic evaluation on children above 13 years with juvenile T inversion pattern which may lead to early diagnosis of cardiomyopathy.

Effect of Atorvastatin on E.C.G changes in Coronary artery disease.

E.C.G is the most widely used test for both the diagnosing and estimating the prognosis of CAD. ST segment and T wave changes are most commonly evaluated parameters of E.C.G. Atorvastatin have found to decrease ischemic events apart from its hypolipidemic effect. The main objective of this open prospective randomized, controlled study was to evaluate the effect of addition of atorvastatin to conventional antianginal treatment on ST segment and T wave changes on E.C.G. The study was conducted for duration of 2 months in 30 patients of CAD (15 in each group). Group A was started on conventional antianginal treatment and group B was started on Atorvastatin 20 mg once a day at night in addition to conventional treatment. The ECG changes were recorded after 15, 30, 45 and 60 days using 12 lead E.C.G. At the end of the study, no significant difference was found in E.C.G changes between the group A and group B. A slight improvement in ST segment changes in group B patients was observed but the effect was statistically not significant. So, addition of atorvastatin to conventional antianginal treatment did not have a significant effect on reversal of ischemic changes on ECG in patients of CAD.

The value of T wave alternans in prediction of ventricular arrhythmias in post-op TOF children / 临床儿科杂志

Objective To explore the value of T wave alternans (TWA) in prediction ventricular arrhythmias in post-op TOF children. Methods The characteristics of TWA were retrospectively analyzed in 36 post-op TOF patients and 120 age-matched normal children. The relationship of sustained TWA and ventricular arrhythmias was also analysed. Results Compared with normal children, the incidence of sustained TWA was significantly increased in post-op TOF group (χ2=6.98, P<0.05). In post-op TOF patients, the incidence of ventricular arrhythmia was much higher when sustained TWA was present (χ2=10.41, P<0.05). Conclusions There exists electrophysiological basis for ventricular arrhythmia in post-op TOF children. Sustained TWA has important value in prediction of ventricular arrhythmia of post-op TOF.

Evaluation of regional myocardial mechanical dysfunction of left ventricle in female patients with ECG T-wave inversion using velocity vector imaging / 中华超声影像学杂志

Objective To evaluate regional myocardial mechanical dysfunction of left ventricle in patients with ECG T-wave inversion using echocardiographic velocity vector imaging.Methods One hundred nineteen female patients with T wave inversion divided into three groups:V1-6 T-wave inversion group(52 patients),V1-4 Twave inversion group (33 patients),V3-6 T-wave inversion group (34patients),while selected 44 healthy women in control group.Peak systolic radial strain (SRSmax) and strain rate (SRSrmax),peak systolic circumferential strain (SCSrmax) and strain rate (SCSmax) were derived and compared from three short-axis views of left ventricle at 18 wall segments using a dedicated Syngo VVI software and workstation,and the depth of T-wave inversion in different precordial lead was measured and correlated with mechanics parameters between four groups.Results In V1-6 T-wave inversion group,each mechanical variable of anteroseptal,anterior,anterolateral and inferolateral walls decreased (P ＜0.05-0.01).In V1-4 T-wave inversion group each mechanical variable of anteroseptal,anterior and inferoseptal walls declined (P ＜0.05-0.01).In V3-6 T-wave inversion group four mechanical variables(i.e.,SRSmax SRSr SCSmax and SCSrmax) of anteroseptal,anterior,anterolateral and inferolateral walls reduced,mainly at basal segment (P ＜0.05-0.01).The ventricular segments of reduced SRSmax,SRSrmax and SCSrmax in V1-6 T-wave inversion group and of SRSrmax in V3-6 T-wave inversion group were more than those in V1-4 T-wave inversion group (P ＜0.05-0.01).In V1-6 T-wave inversion group,negative correlationships between radial mechanical variables of anteroseptal wall and the depths of V4 and V5 lead T-wave inversion were found (r =-0.29--0.37,P ＜0.05-0.01).Otherwise a positive correlationships between SCSmax of anterolateral wall and the depth of V3 lead T-wave inversion were established (rs =0.44,P =0.01) in V1-4 T-wave inversion group.Conclusions There is a regional myocardial dysfunction of LV in female patients with ECG T-wave inversion.The extent of electrical repolarization abnormality is correlated to the severity of regional myocardial dysfunction.