Journal of electrocardiology
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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.
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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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Electrocardiographic low QRS voltage (LQRSV) has many causes, which can be differentiated into those due to the heart's generated potentials (cardiac) and those due to influences of the passive body volume conductor (extracardiac). Peripheral edema of any conceivable etiology induces reversible LQRSV, reduces the amplitude of the P waves and T waves, decreases the duration of P waves, QRS complexes, and QT intervals, and alters in turn the measurements of the signal-averaged electrocardiogram and T wave alternans, all with enormous clinical implications.
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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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Atrioventricular block is usually transient during the course of infectious myocarditis. We report the case of a patient presenting with complete infra-hisian atrioventricular block occurring in the setting of infectious myocarditis and in whom a pacemaker should be finally implanted. ⋯ Complete atrioventricular block persisted during the two years of follow-up despite otherwise complete regression of the myocarditis. We then discuss the main features of conduction disturbances complicating infectious myocarditis, including a list as complete as possible of all the causal agents possibly involved.