Momentary giant T‐waves hint the genesis of the electrocardiographic T‐wave in human

Background: Apical hypertrophic cardiomyopathy (apical HCM) is a less common subtype of HCM characterized by a focal thickening in the left ventricular apex. “Classic” ECG features have been described, however, apical HCM can persist for many years without detection. We investigated the relationship between ECG findings and echocardiographic morphometry in a large referral series of patients with apical HCM. Methods: We enumerated all patients diagnosed with apical HCM prior to Sept. 30, 2006 using the Mayo Clinic HCM database. We compared echocardiographic measures separately for patients with positive status for two ECG indices of left ventricular hypertrophy (LVH); the Sokolow-Lyon index and the Romhilt-Estes (RE) point-score. We also compared echocardiographic measurements in patients with and without negative T-waves in the precordial leads. Results: Apical HCM was detected in 177 patients (111 men and 68 women). Only 51% had positive Sokolow criteria and 51% had positive RE criteria. The agreement between Sokolow and RE status was high (agreement = 75.0%; kappa = 0.50; 95% CI = 0.38 – 0.62). In particular, Sokolow positive patients had increased LV ejection fraction (P = 0.02), and decreased LV end-systolic diameter (P = 0.03) compared with Sokolow negative patients. The prevalence of right atrial enlargement (47 vs. 28%; P = 0.02) and intracavity obstruction (22 vs. 8%; P = 0.01) were more common in Sokolow positive patients. Positive RE criteria was associated with a greater thickness of the basal septal and basal posterior walls (P = 0.001 and 0.02, respectively), and with a higher frequency of intracavity obstruction (21 vs. 9%; P = 0.04). Most patients (89%) exhibited at least one negative T-wave in the precordial leads; however, only 10% of patients had a negative T-wave of greater than 1.0 mV. We found that patients with an inverted T-wave larger than 0.4 mV (median) had a significantly increased LV ejection fraction (P = 0.03) compared with patients who had smaller or no negative T-waves. Conclusions: Among patients with apical HCM, nearly half do not have ECG evidence of LVH based on classic criteria and most do not have marked T-wave inversions. However, the majority did have at least a mild expression of negative T-waves.

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Physiological ECG Value for Polish Half-Bred Anglo-Arab Horses

Bulletin of the Veterinary Institute in Pulawy ◽

10.2478/v10213-012-0111-4 ◽

2012 ◽

Vol 56 (4) ◽

pp. 631-635 ◽

Cited By ~ 1

Keyword(s):

Heart Rate ◽

P Wave ◽

P Waves ◽

T Wave ◽

Duration Time ◽

Qt Intervals ◽

Electrocardiographic Examination ◽

Electrocardiographic Findings ◽

Almost All ◽

T Waves

Abstract The electrocardiographic examination was performed in 33 training horses (2-16 years of age, 11 males and 22 females). Einthoven and precordial leads (I, II, III, aVR, aVL, aVF, CV1, CV2, CV4) were used. The ECG was performed in resting horses and immediately after exercise (10 min walk, 15 min trot, 10 min canter) using a portable Schiller AT-1 3-channel electrocardiograph, with a paper speed of 25 mm sec-1 and a sensitivity of 10 mm.mV-1. The heart rate, wave amplitudes, and duration time were estimated manually. All horses presented a significant increase in heart rate after exercise (rest 43.83 ±10.33 vs. exercise 73.2 ±14.8). QT intervals were significantly shortened in most of the leads. In resting horses, all P waves in the lead I were positive and almost all II, III and CV4 leads were positive. Simple negative P wave dominated in aVR and only simple negative T wave was found in the leads I. The biphasic shape was observed. After exercise, the amplitude of P and T waves rose, however, clear changes were not observed in wave polarisation and form. In the absence of specific racial characteristics of the electrocardiogram in the Polish Anglo- Arabians, electrocardiographic findings can be interpreted according to ECG standards adopted for horses.

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Differences in the diagnostic value of various criteria of negative T waves for hypertrophic cardiomyopathy based on a molecular genetic diagnosis

Clinical Science ◽

10.1042/cs20060293 ◽

2007 ◽

Vol 112 (11) ◽

pp. 577-582 ◽

Cited By ~ 12

Author(s):

Tetsuo Konno ◽

Noboru Fujino ◽

Kenshi Hayashi ◽

Katsuharu Uchiyama ◽

Eiichi Masuta ◽

...

Keyword(s):

Hypertrophic Cardiomyopathy ◽

Molecular Genetic ◽

Genetic Diagnosis ◽

Diagnostic Value ◽

Left Ventricular ◽

Lower Sensitivity ◽

T Wave ◽

Accurate Definition ◽

Definition Of ◽

T Waves

Differences in the diagnostic value of a variety of definitions of negative T waves for HCM (hypertrophic cardiomyopathy) have not yet been clarified, resulting in a number of definitions being applied in previous studies. The aim of the present study was to determine the most accurate diagnostic definition of negative T waves for HCM in genotyped populations. Electrocardiographic and echocardiographic findings were analysed in 161 genotyped subjects (97 carriers and 64 non-carriers). We applied three different criteria that have been used in previous studies: Criterion 1, negative T wave >10 mm in depth in any leads; Criterion 2, negative T wave >3 mm in depth in at least two leads; and Criterion 3, negative T wave >1 mm in depth in at least two leads. Of the three criteria, Criterion 3 had the highest sensitivity (43% compared with 5 and 26% in Criterion 1 and Criterion 2 respectively; P<0.0001) and retained a specificity of 95%, resulting in the highest accuracy. In comparison with abnormal Q waves, negative T waves for Criterion 3 had a lower sensitivity in detecting carriers without LVH (left ventricular hypertrophy) (12.9% for negative T waves compared with 22.6% for abnormal Q waves). On the other hand, in detecting carriers with LVH, the sensitivity of negative T waves increased in a stepwise direction with the increasing extent of LVH (P<0.001), whereas there was less association between the sensitivity of abnormal Q waves and the extent of LVH. In conclusion, Criterion 3 for negative T waves may be the most accurate definition of HCM based on genetic diagnoses. Negative T waves may show different diagnostic value according to the different criteria and phenotypes in genotyped populations with HCM.

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Seismic T-Wave Observations at Dense Seismic Networks

Seismological Research Letters ◽

10.1785/0220200208 ◽

2020 ◽

Vol 91 (6) ◽

pp. 3444-3453

Author(s):

Catherine D. de Groot-Hedlin

Keyword(s):

Wave Propagation ◽

West Coast ◽

East Coast ◽

Seismic Energy ◽

Polarization Analysis ◽

The West ◽

P Waves ◽

Transverse Waves ◽

T Wave ◽

T Waves

Abstract Seismic T waves, which result from transformation of hydroacoustic to seismic energy at coastlines, were investigated for two strong earthquakes. A 2014 Caribbean event generated seismic T waves that were detected at over 250 seismometers along the east coast of the U.S., primarily at seismic stations operated by the USArray Transportable Array. A 2006 Hawaiian event generated seismic T waves observed at over 100 seismometers along the west coast. Seismic T-wave propagation was treated as locally 2D where the incoming hydroacoustic wavefronts were nearly parallel to the coastlines. Along the east coast, seismic T-wave propagation velocities were consistent with surface waves and a polarization analysis indicated that they were transverse waves, supporting their interpretation as Love waves. They were observed at inland distances up to 1134 km from the east coast. Along the west coast, the propagation velocity was over 5 km/s and a polarization analysis confirmed that the seismic T waves propagated as seismic P waves. Differences between the modes of propagation along the east and west coasts are attributed to differences in the slope and thickness of the sediment coverage at the continental slopes where hydroacoustic to seismic conversion takes place.

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Prolongation of Electrocardiographic T Wave Parameters Recorded during the Head-Up Tilt Table Test as Independent Markers of Syncope Severity in Children

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17186441 ◽

2020 ◽

Vol 17 (18) ◽

pp. 6441

Author(s):

Grażyna Markiewicz-Łoskot ◽

Ewelina Kolarczyk ◽

Bogusław Mazurek ◽

Marianna Łoskot ◽

Lesław Szydłowski

Keyword(s):

Vasovagal Syncope ◽

The Other ◽

Control Group ◽

Tilt Table Test ◽

Tilt Table ◽

T Wave ◽

Good Discriminator ◽

Wave Morphology ◽

Head Up Tilt ◽

T Waves

The head-up tilt table test (HUTT) with the upright phase is used to help determine an imbalance of the sympathetic nervous system that is related to abnormal electrocardiographic repolarization in children with vasovagal syncope (VVS) and also in patients with the long QT syndrome (LQTS). The study attempted to evaluate T wave morphology and QT and TpTe (Tpeak–Tend) intervals recorded in ECG during the HUTT for a more accurate diagnosis of children with VVS. The group investigated 70 children with a negative HUTT result: 40 patients with VVS and 30 healthy volunteers without syncope. The RR interval as well as TpTe, and QTc intervals were measured in lead V5 of electrocardiogram (ECG) on admission to the hospital and during three phases of the HUTT. In syncopal children, which included 23 children with bifid or flat T waves and 17 patients with normal T waves in the upright phase, the QTc and TpTe were longer (p < 0.001) compared to the other test phases and longer (p < 0.001) than in the control group, respectively, with the risk of arrhythmias. Only in the control group, the TpTe was shorter (p < 0.001) in the upright phase than in the other tilt phases. The TpTe in the upright phase (>70 ms) was a good discriminator, and was better than the QTc (>427 ms). Prolongation of electrocardiographic TpTe and QT intervals, in addition to the (abnormal T wave morphology recorded during the HUTT, are helpful for identifying VVS children more predisposed to ventricular arrhythmias with a latent risk of LQTS. Further studies are required to assess the value of these repolarization parameters in clinical practice.

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THE INFLUENCE OF DIGITALIS ON THE T WAVE OF THE HUMAN ELECTROCARDIOGRAM

Journal of Experimental Medicine ◽

10.1084/jem.21.6.593 ◽

1915 ◽

Vol 21 (6) ◽

pp. 593-603 ◽

Cited By ~ 38

Author(s):

Alfred E. Cohn ◽

Francis R. Fraser ◽

Ross A. Jamieson

Keyword(s):

Initial Curve ◽

T Wave ◽

T Waves

It has been shown in this investigation that digitalis, administered orally to patients, can modify the T wave in the electrocardiogram. When the T wave in the initial curve is directed upward, the first change noticed is a lowering, and the final change is an inversion of the wave. It is not only the wave itself, but that portion of the curve between the end of R and the end of T which is involved. Instances in which the initial T waves have other than upright forms are described and their behavior under the influence of digitalis has been indicated. This influence of digitalis on the T wave may be detected in thirty-six to forty-eight hours after the administration of digitalis has commenced; it may persist as long as twenty-two days after the administration has been stopped. Instances where it persisted only five days have been encountered. The unexpected length of duration of the sign probably explains why a second treatment with digitalis requires a smaller amount of the drug to produce the same effect, than the first.

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Inverted Takotsubo contractile pattern caused by pheochromocytoma with tall upright T-waves, but not typical deep T-wave inversion

International Journal of Cardiology ◽

10.1016/j.ijcard.2008.06.073 ◽

2010 ◽

Vol 139 (2) ◽

pp. e15-e17 ◽

Cited By ~ 9

Author(s):

Shinpei Kimura ◽

Wataru Mitsuma ◽

Masahiro Ito ◽

Hiromi Suzuki ◽

Yukio Hosaka ◽

...

Keyword(s):

T Wave ◽

Wave Inversion ◽

T Waves

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Do M-cells contribute significantly in T-wave morphology during normal and arrhythmogenesis conditions like short QT Syndrome?

10.1101/2020.05.28.121079 ◽

2020 ◽

Author(s):

Ponnuraj Kirthi Priya ◽

Srinivasan Jayaraman

Keyword(s):

Cell Types ◽

M Cells ◽

Short Qt Syndrome ◽

M Cell ◽

T Wave ◽

Wave Morphology ◽

Qt Syndrome ◽

Premature Beats ◽

Low Amplitude ◽

T Waves

AbstractAimsThis paper proposes to explain the mechanism of M-cells, particularly its role in the T-wave generation and its contribution to arrhythmogenesis in short QT syndrome 2 (SQTS2).MethodsA 2D transmural anisotropic ventricular model made up of three principal cell types were developed. Different setups in which: a) entire column of mid-myocardial (mid) cells, b) single island of cells c) two island of cells within the mid-layer d) single island of cells in endocardial (endo)-mid layer were considered as M-cells. These setups are stimulated to explain i) contribution of M-cells in T-wave morphology ii) arrhythmia generation phenomena under SQTS2 heterozygous gene mutation by creating pseudo ECGs from the tissue.ResultsFindings infer that setups with an entire layer of M-cells and a higher percentage of epicardial (epi) cells exhibit positive T-waves. Increasing the size of the island in M-cell island setups results in an increased positive T-peak. Placing the M-cell island in the bottom of the mid-layer produced low amplitude T-waves. Further, in two M-cell islands setup, a higher T-wave amplitude was observed when the islands are placed closer than far apart. Moving the M-cell island slightly into the endo layer increases the amplitude of the T-wave. Lastly, on including SQTS2 conditions and pacing with premature beats, an arrhythmia occurs only in those setups containing a layer of M-cells compared to M-cells island setup.ConclusionThese simulation findings paved the way for a better understanding of the M-cells functionality in T-wave morphology as well as promoting arrhythmogenesis under SQTS2 condition.

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Ca2+ Signaling Triggered by Shear-Autocrine P2X Receptor Pathway in Rat Atrial Myocytes

Cellular Physiology and Biochemistry ◽

10.1159/000495089 ◽

2018 ◽

Vol 50 (6) ◽

pp. 2296-2313 ◽

Cited By ~ 5

Author(s):

Joon-Chul Kim ◽

Min-Jeong Son ◽

Sun-Hee Woo

Keyword(s):

Shear Stress ◽

Membrane Potential ◽

Atp Release ◽

P2x Receptor ◽

Luciferase Assay ◽

Atrial Myocytes ◽

Patch Clamp Technique ◽

T Wave ◽

Connexin Hemichannels ◽

T Waves

Background/Aims: The atrium is exposed to high shear stress during heart failure and valvular diseases. We aimed to understand atrial shear-induced Ca2+ signaling and its underlying mechanisms. Methods: Pressurized micro-flow was applied to single rat atrial myocytes, and Ca2+ signal, membrane potential, and ATP release were assessed using confocal imaging, patch clamp technique, and luciferin-luciferase assay, respectively. Results: Shear stress (∼16 dyn/cm2) induced global Ca2+ waves (∼0.1 events/s) from the periphery to the center of cells in a transverse direction (“T-wave”; ∼145 μm/s). Pharmacological interventions and simultaneous recording of membrane potential and Ca2+ demonstrated that shear-induced T-waves resulted from action potential (AP)-triggered Ca2+ release from the sarcoplasmic reticulum. T-waves were not sensitive to inhibitors of known shear signaling mechanisms except connexin hemichannels and ATP release. Shear stress caused ATP release from these myocytes (∼1.1x10-17 moles/unit membrane, µm2); ATP release was increased by enhancement of connexin hemichannels and suppressed by inhibition of the hemichannels, but not affected by inhibitors of other ATP release pathways. Blockade of P2X receptor, but not pannexin or the Na+-Ca2+ exchanger, eliminated shear-induced T-wave initiation. Conclusion: Our data suggest that shear stress triggers APs and concomitant Ca2+ signaling via activation of P2X receptors by connexin hemichannel-mediated ATP release in atrial myocytes.

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