Journal of electrocardiology
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Case Reports
Wellens syndrome associated with prominent anterior QRS forces: an expression of left septal fascicular block?
Wellens syndrome is a clinical-electrocardiographic entity also referred to as left anterior descending (LAD) coronary T-wave syndrome or acute coronary T-wave syndrome. It is a complex of symptoms and signals indicating the existence of an undesirable condition secondary to critical high-grade proximal stenosis of the LAD coronary artery characterized by the association of prior history of acute coronary syndrome with little or no elevation of markers of myocardial damage (unstable angina) and characteristic electrocardiographic changes consistent with subepicardial anterior ischemic pattern (persistently symmetrical, deep negative and broad-based T waves) or plus-minus T waves with inversion of the terminal portion in the LAD coronary artery territory (V1 through V5 or V6). We present a case of a variant of Wellens syndrome that reveals association and, transitorily, the criteria described in literature for left septal fascicular block.
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The effects of three common limb electrode placement configurations on ECG signal morphology were examined, including the standard electrode placement of the electrodes on the extremities, the Mason-Likar placement, and the Lund placement. A non-traditional asymmetric configuration of placing the LA electrode on the upper arm with the RA electrode on the torso (below the clavicle) was also investigated. A series of 16-lead ECGs were acquired from 150 subjects representing a broad range of diseases. ⋯ Over half (13 of 25) of the ECGs exhibiting criteria for inferior infarct in the standard configuration had that criteria erased when the electrodes were moved to the Mason-Likar positions. The largest single effect on the ECG resulted from moving the LA electrode from the shoulder to the clavicle. The asymmetric configuration with the RA electrode on the torso and the LA electrode on the upper arm may offer some compromise between noise and faithfulness to the standard configuration in noisy environments such as exercise testing or monitoring.
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An important subset of patients (approximately 10%) with chest pain and ST-segment elevation on initial electrocardiogram (ECG) do not have acute coronary occlusion. In our experience, 5% of women presenting with chest pain and ST-segment elevation are proven to have the newly recognized syndrome of tako-tsubo (stress) cardiomyopathy (TC). Patients with TC present with clinical and electrocardiographic features mimicking ST-segment elevation anterior myocardial infarction due to left anterior descending (LAD) occlusion. ⋯ In conclusion, patients with TC frequently present with anterior ST-segment elevation, which cannot be reliably distinguished from that of acute LAD occlusion. In TC, the combination of minimal troponin release, absent delayed hyperenhancement on cardiac magnetic resonance imaging (in most of patients), and return to normal LVEF is consistent with the presence of significant myocardial stunning. The ECG evolution of progressive T-wave inversion, QTc interval lengthening, and R-wave reappearance could be the electrophysiologic manifestation of an underlying stunned myocardium in this condition.
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Clinical Trial
Investigating the effect of sotalol on the repolarization intervals in healthy young individuals.
The dissociation between a drug-induced increase of the QT interval prolongation and an increased risk for ventricular arrhythmias has been suggested by academic investigators and regulatory agencies. Yet, there are no alternative or complimentary electrocardiographic (ECG) techniques available for assessing the cardiotoxicity of novel compounds. In this study, we investigated a set of novel ECG parameters quantifying the morphology of the T-loop. In a group of healthy individuals exposed to sotalol, we compared their drug-induced changes to the drug-induced prolongations of the QTc, QTc apex and T-peak to T-end intervals. ⋯ This study describes the sotalol-induced changes of the T-loop morphology in healthy individuals based on novel vectocardiographic parameters. These observations might help in improving the next generation of ECG markers for the evaluation of drug cardiotoxicity.
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Magnetic resonance imaging using the delayed contrast-enhanced (DE-MRI) method can be used for characterizing and quantifying myocardial infarction (MI). Electrocardiogram (ECG) score after the acute phase of MI can be used to estimate the portion of left ventricular myocardium that has infarcted. There are no comparison of serial changes on ECG and DE-MRI measuring infarct size. ⋯ In conclusion, the Selvester QRS scoring system is in half of the patients with reperfused first time MI in good accordance with DE-MRI in identifying a decrease or no change in the extent of left ventricle occupied by infarction in the acute and chronic phases.