Osman Can YONTAR, Gözde YONTAR, Ahmet TÜTÜNCÜ, Kemal KARAAĞAÇ, Erhan TENEKECİOĞLU, Alper KARAKUŞ, Mehmet MELEK

Olanzapin Kullanımı QT İntervali Normal Ölçülen Hastalarda T Dalga Tepe- T Dalga Sonlanım Noktaları İntervalini Uzatır

Amaç: Antipsikotik ilaçların QT intervalini uzatarak ani kardiyak ölüme yol açabildikleri uzun süredir bilinmektedir. İkinci nesil antipsikotikler, düşük aritmik etkileri nedeniyle birinci nesilden daha güvenli olarak değerlendirilmektedir. Olanzapin en sık kullanılan ikinci nesil antipsikotiklerden birisidir ancak QT intervaline olan etkisi için çelişkili veriler mevcuttur. Yapılan çalışmalar, 12-kanal elektrokardiyogramda T dalga tepe noktasından sonlanım noktasına kadar ölçülen intervalin (Tp-e) uzamasının ventriküler aritmogenezin belirteci olduğunu göstermektedir. Çalışmamızın amacı, olanzapin tedavisi altındaki hastaların ventriküler repolarizasyon anormalliklerini Tp-e, Qt ve QTc intervalleri ve Tp-e/QT oranı kullanarak değerlendirmektir. Materyal ve Metot: Hasta kayıtları retrospektif olarak incelendi. En az 3 aydır olanzapin kullanmakta olan şizofreni hastalarının EKG'leri incelendi.Yaş ve cinsiyet uyumlu kontrol grubu da karşılaştırma için gruba dahil edildi. Yüzeyel EKG'lerin dijital ortamda bilgisayar programıyla QT, QTc ve Tp-e intervalleri ölçüldü. Bulgular: Her iki grubun demografik özellikleri benzerdi. Hastaların kullandığı Ortalama günlük olanzapin dozu 20,3±7 mg idi. Her iki grup QT (371,8±55,4 vs. 362,61±34,7; p=0,440) ve QTc (455,98±49,3 vs. 434,48±43,724; p=0,077) intervalleri açısından farksızdı. Ancak Tp-e intervali olanzapin kullanan hastalarda anlamlı olarak uzamış bulundu (89,5±31,8 vs. 76,4±9,8; p=0,039). Sonuç: T dalgası tepe noktası-sonlanım noktası intervali, sol ventrikül transmural repolarizasyon dispersiyonunun göstergesi ve ventriküler aritmogenez belirteci olarak kabul edilmektedir. Tp-e/QT ise daha yeni bir parametre olup aynı defektlere işaret etmektedir. Bulgularımız, yalnızca olanzapin tedavisi alan hastalarda sağlıklı bireylere göre uzamış Tp-e intervali ve daha yüksek Tp-e/QT (p=0,041) göstermiştir. Antipsikotikler QT intervalini uzatmayabilir, ancak sadece Tp-e segmentindeki uzama da repolarizasyon heterojenitesine işaret edebilir. Tp-e ve Tp-e/QT ölçümlerinin antipsikotik olanzapin kullanan hastalarda ventriküler aritmi riskinin belirteci olabileceğini düşünüyoruz.

Anahtar Kelimeler:

Tp-e, aritmi, olanzapin

Olanzapıne Usage Prolongs T Wave Peak To T Wave End Segment In Patıents Wıth Normal QT Interval

Background: Antipsychotic drugs are long known to cause prolongation in QTinterval which is a marker of increased risk for sudden cardiac death. Studies indicate that prolongation of the interval between the peak and end of the T wave (Tpeak to Tend, Tp-e) on the 12-lead ECG, is a marker of ventricular arrhythmogenesis. The aim of this study was to assess ventricular repolarization in patients who are on antipsychotic therapy by using Tp-e, QTand QTc interval and Tp-e/QTratio. Material and Method: Patient records were retrospectively analyzed. Electrocardiogram of 31 patients, who were on antipsychotic drug therapy (olanzapine) at least 3 months, were obtained and scanned. T wave peak to end interval, QT and corrected QT (QTc) intervals and some other ECG intervals were measured. Electrocardiograms of age and sex matched 31 healthy control individuals were also analyzed for comparison. Patients with critical coronary stenosis, moderate or severe valve disease, left and/or right heart failure, left and/or right ventricle hypertrophy, atrial fibrillation, right or left bundle block or patients who got pacemaker or ICD implanted were excluded. Results: Both groups' baseline characteristics were similar. Mean olanzapine dose for patients was 20,3±7 mg. Both groups did not differ in QT (371,8±55,4 vs. 362,61±34,7; p=0,440) and QTc (455,98±49,3 vs. 434,48±43,724; p=0,077) interval measurements. However, patients who were on olanzapine had significantly longer Tp-e (89,5±31,8 vs. 76,4±9,8; p=0,039) than controls. Discussion: T wave peak to end interval is a measure of transmural dispersion of repolarization in the left ventricle and accepted as a surrogate for increased ventricular arrhythmogenesis risk. Tp-e/QTis a relatively new marker which also indicates repolarization defects. Antipsychotic drugs are claimed to be responsible for QT prolongation and increase risk for Torsades de pointes. Our findings show that patients who are on olanzapine treatment alone, have significantly longer Tp-e and higher Tp-e/QT(0,23 vs. 0,21; p=0,041) than healthy controls. Antipsychotics may not prolong QT interval, however; may cause repolarization heterogeneity and lengthen the Tp-e segment of whole QT interval. Tp-e and Tp-e/QT are suggestive surrogates of ventricular arrhythmogenesis risk in patients who are on antipsychotic drugs.

Keywords:

Tp-e, arrhythmia, olanza,

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