Reversal of primary and pseudo-primary T wave abnormalities by ventricular pacing. A novel manifestation of cardiac memory
| Autor: | Carlos B. Álvarez, Pablo A. Chiale, Julio D. Pastori, Rubén Argüero Sánchez, Marcelo V. Elizari, Oscar Ianovsky, Mario D. Gonzalez, Hugo A. Garro, Luciano Faivelis |
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| Rok vydání: | 2009 |
| Předmět: |
Adult
Male medicine.medical_specialty Adolescent Heart Ventricles Action Potentials QT interval Risk Assessment Statistics Nonparametric QRS complex Electrocardiography Ventricular Dysfunction Left Young Adult Heart Conduction System Reference Values Physiology (medical) T wave Internal medicine medicine Ventricular outflow tract Humans cardiovascular diseases Mean T Wave Axis Aged medicine.diagnostic_test business.industry Body Surface Potential Mapping Cardiac Pacing Artificial Middle Aged Anesthesia Coronal plane Case-Control Studies cardiovascular system Cardiology Tachycardia Ventricular Female Electrical conduction system of the heart Cardiology and Cardiovascular Medicine business Follow-Up Studies |
| Zdroj: | Journal of interventional cardiac electrophysiology : an international journal of arrhythmias and pacing. 28(1) |
| ISSN: | 1572-8595 |
| Popis: | "Cardiac memory" refers to abnormal T waves (TW) appearing after transient periods of altered ventricular depolarization. The aim of the study was to test the hypothesis that in the presence of abnormal TW, short periods of tailored ventricular pacing (VP) can be followed by normalization of ventricular repolarization.Ten patients with normal TW (control group) and 18 patients with abnormal TW (study group) underwent 15 min of VP at a cycle length of 500 ms. In the control group, VP was performed from the right ventricular apex, and in the study group from right or left ventricular sites that resulted in paced QRS complexes of opposite polarity to that of the abnormal TW. Before and after VP, atrial pacing was maintained at a stable cycle length. Simultaneous 12-lead electrocardiography (ECG) was recorded before, during, and following VP to assess changes in TW polarity, amplitude, electrical axis, QTc interval, and QTc interval dispersion.As expected, VP was followed by memory-induced changes in TW in eight of ten patients in the control group. Mean T wave axis shifted from +60 degrees + or - 21.2 degrees to +23.5 degrees + or - 50.7 degrees (p = 0.01) in the frontal plane. In the study group, complete or partial normalization of TW occurred in 17 of 18 patients. Mean T wave axis shifted from -23.7 degrees + or - 22.9 degrees to +19.7 degrees + or - 34.7 degrees (p0.0002) in the frontal plane when paced from right ventricular outflow tract. The QTc interval shortened after VP both in the control group (424 + or - 25 vs. 399 + or - 27 ms; p = 0.007) and in the study group (446 + or - 26 vs. 421 + or - 22 ms; p0.0002). No significant changes were found in QTc interval dispersion.Transient changes in the sequence of ventricular activation may either induce or normalize abnormal TW. The background of preceding ventricular depolarization needs to be taken into account before determining the clinical significance of a given pattern of ventricular repolarization. |
| Databáze: | OpenAIRE |
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