Journal of electrocardiology
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Randomized Controlled Trial Clinical Trial
QT dispersion increases during intubation in patients with coronary artery disease.
Anesthetic drugs have been shown to increase QT interval, however data regarding their effects on QT dispersion (QTd) are scarce, especially in patients with coronary artery disease (CAD). We tested whether induction of Anesthesia with thiopental and etomidate would increase QTd in patients with CAD. Thirty American Society of Anesthesiologists (ASA) physical status I-II patients without CAD were randomly allocated to groups I (n = 15) and II (n = 15) and 30 ASA physical status III patients with CAD were randomly allocated to groups III (n = 15) and IV (n=15). ⋯ Likewise, QT dispersion also increased during intubation in patients with CAD induced with etomidate (from 41.5 +/- 17.2 ms to 80.0 +/- 33.6 ms; P <.001). There was no increase in QT dispersion in patients without known CAD. QT dispersion seems to be increased during the intubation period in patients with CAD regardless of the induction agents used.
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Case Reports
Reversible left ventricular dysfunction "takotsubo" cardiomyopathy related to catecholamine cardiotoxicity.
An 80-year-old female was admitted for a persistent consciousness disturbance. Electrocardiography revealed ST-segment elevation in leads II, III, aVf, and V3-V6. Coronary angiography demonstrated normal arteries, while left ventriculography revealed asynergy of apical akinesis and basal hyperkinesis. ⋯ Within 24 days, the asynergy improved without any specific treatment, but the giant negative T waves were present on the electrocardiogram. The plasma norepinephrine and brain natriuretic peptide levels on the first hospital day were 2.9ng/mL and 906pg/mL, respectively. The left ventricular dysfunction appeared to be induced by the exposure to high-level plasma catecholamines. (123)I-metaiodobenzyl guanidine scintigraphy also revealed transient dysfunction of the cardiac catecholamine dynamics.
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Comparative Study
Assessment of the RR versus QT relation by a new symbolic dynamics method. Gender differences in repolarization dynamics.
A new method based on symbolic dynamics was applied to assess RR-QT dynamics and to compare gender differences. Segments of 10,000 RR and QT from the night were selected. The values of RR and QT were coded as follows. ⋯ In discriminant analysis, when QTc was ignored in the model, the RR-QT dynamics separated genders with 67% accuracy (chi(2) = 9.1, P <.003). RR-QT dynamics can be analyzed with symbolic dynamics methods. The gender differences in repolarization are not only due to QTc duration alone but also result from the dependence of the duration of QT on the RR duration.
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Case Reports
Electrocardiographic demonstration of intermittent left bundle branch block because of the "linking" phenomenon.
The authors describe a patient who showed intermittent left bundle branch block at a slow heart rate. The perpetuation of left bundle branch block is suggested because of rate dependent bundle branch block and trans-septal retrograde concealed penetration by the contralateral bundle as it is resolved by a premature ventricular extrasystole. This phenomenon is called "linking." This case report aims to present and emphasize this interesting phenomenon.