Uma Questão à Espera de ser Esclarecida: Efeito de Fármacos Prolongadores de QT no Intervalo Tp-e
| Autor: | Emrah Erdal, Mehmet Dogan, Omer Yiginer |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Male
Bradycardia lcsh:Diseases of the circulatory (Cardiovascular) system medicine.medical_specialty Doenças Cardiovasculares Eletrocardiologia Context (language use) QT interval Electrocardiography Death Sudden Torsades de Pointes Internal medicine medicine Humans Psychotropic /drugs therapeutic Repolarization In patient Letter to the Editor Psychotropic Drugs business.industry Heart medicine.disease Surgery Obstructive sleep apnea Morte Súbita Electrophysiology lcsh:RC666-701 Cardiovascular Diseases Fibrilação Atrial Ventricular Fibrillation Cardiology Interval (graph theory) Female Psicotópicos/uso terapêutico medicine.symptom Cardiology and Cardiovascular Medicine business |
| Zdroj: | Arquivos Brasileiros de Cardiologia, Volume: 104, Issue: 6, Pages: 507-508, Published: JUN 2015 Arquivos Brasileiros de Cardiologia, Vol 104, Iss 6, Pp 507-508 (2015) Arquivos Brasileiros de Cardiologia |
| ISSN: | 0066-782X |
| Popis: | We read the article ‘Impact of Psychotropic Drugs on QT Interval Dispersion in Adult Patients’ by Claudio et al. with great interest1. They investigated in this study the effects of psychotropic drugs on QT interval (QTI), corrected QT interval (QTc), and QT dispersion (QTd). They concluded that psychotropic drugs increased QTd and QTc interval. QTd is the most frequently used non-invasive method to quantify electrical myocardial heterogeneity. However, there are variable results in studies related to QTI due to the technical limitations in measurements2. It is well-known that the reproducibility of QTI measurements is low both in manual and automatic measurements2. In this study, the measurements were performed digitally by four cardiologists using the Preview software with a magnification of 300%. We appreciated the method used in this study in order to obtain more accurate data. It is recommended that measurements be done digitally at least by two cardiologists2. Quantifying electrical myocardial heterogeneity and transmural dispersion of repolarization (TDR) was introduced in the beginning of 2000’s3. The myocardium comprises 3 distinct myocyte types - namely, endocardial, epicardial, and midmyocardial M cells3. Although these myocytes are morphologically similar, they exhibit different electrophysiological characteristics. M cells have typically the longest action potential. Furthermore, when myocardium is exposed to conditions prolonging the repolarization phase, such as bradycardia or agents, the action potential duration of the M cells are more prolonged than in the other cells3. While repolarization of the epicardial region ends at the peak of T-wave, repolarization phase of M cells ends at the end of T wave3. Therefore, the time between the peak and end of the T wave is called Tp-e interval, as an index of TDR. The role of the TDR in the prediction of possible life‑threatening arrhythmic events has been demonstrated in the Brugada, short-QT and long-QT syndromes and coronary artery disease3. Previously, we showed that TDR was increased in patients with obstructive sleep apnea and chronic arsenic exposure4,5. However, there is no study investigating the effects of QT prolonging drugs on TDR. The repolarization phase of myocytes in midmyocardial and endocardial layers may be more influenced by the drugs. In this context, psychotropic drugs may be increasing QT interval duration via Tp-e interval prolongation. In conclusion, it seems that adding the data related to Tp-e interval to the study results might have completely illuminated the effects of psychotropic drugs on electrical heterogeneity of myocardium in many respects. |
| Databáze: | OpenAIRE |
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