QT dispersion in patients with chronic and advanced heart failure: Is it only a methodological problem?

Abstract

Aim: QT dispersion is a potential predictive marker for ventricular tachyarrhythmia events and sudden cardiac death (SCD). However, prior investigations on the prognostic value of QT dispersion in patients with chronic heart failure (CHF) have shown conflicting results. Therefore, the present study aims to assess the prognostic value of QT dispersion in patients with CHF. Material and Methods: A total of 66 patients with CHF (LVEF ≤35%, functional class NYHA II/III) were included in the study. Baseline ECG recording, Holter monitoring, equilibrium radionuclide ventriculography, and cardiopulmonary exercise test were carried out in all patients. Findings of the patients who experienced SCD group during the follow-up were compared with survivors. Results: Over 36.7 ± 11.7 months follow-up, 10 patients (7 of 10 with SCD) died, and 3 patients underwent cardiac transplantation. Mean heart rate (101 ± 23 vs. 81 ± 12bpm, p <0.006) and NHYA class (2.6 ± 0.5 vs. 2.0 ± 0.7; p <0.03) were significantly higher, and LVEF (16 ± 4 vs. 27 ± 8%, p <0.006) was significantly lower in the SCD group. No significant differences between the two groups were found for peak VO2 (13.6 ± 7.4 vs. 17.2 ± 5.8ml/kg/min, p =0.138), heart rate variability (88 ± 51 vs. 133 ± 59ms, p =0.059) and QT dispersion (88 ± 51 vs. 90 ± 35ms, p =0.089). Conclusions: Present findings indicate that in patients with chronic and advanced heart failure, both a decreased LVEF and increased heart rate but not QT dispersion provide predictive information on SCD.

Keywords

• QT dispersion
• heart failure
• prognosis
• mortality

Kronik ve ileri evre kalp yetmezliği hastalarında QT dispersiyonu: Sadece metodolojik sorun mu?

Abstract

Amaç: QT dispersiyonu ventriküler taşiaritmi ve ani kardiyak ölüm (AKÖ) olayları için potansiyel bir belirteçtir. Ancak, kronik kalp yetmezliği (KKY) olan hastalarda QT dispersiyonunun prognostik değeri üzerine yapılan önceki araştırmalar çelişkili sonuçlar göstermiştir. Bu çalışma, ileri evre KKY olan hastalarda QT dispersiyonunun prognostik değerini araştırmayı amaçlamaktadır. Gereç ve Yöntemler: Çalışmaya 66 ileri evre KKY olan hasta (sol ventriküler ejeksiyon fraksiyonu (SVEF) ≤%35, fonksiyonel sınıf NYHA II/III) dahil edildi. Tüm hastalarda başlangıçta EKG kaydı, holter monitörizasyonu, radyonüklid ventrikülografi ve kardiyopulmoner egzersiz testi yapıldı. Takip sırasında AKÖ grubu olan hastaların bulguları sağ kalanlarla karşılaştırıldı. Bulgular: Toplam 36,7 ± 11,7 ay üzerinde takipte, 10 hasta (7'sinde AKÖ) öldü ve 3 hastaya kalp nakli uygulandı. Ortalama kalp atış hızı (101 ± 23'e karşı 81 ± 12/dk., p <0,006) ve NHYA sınıfı (2,6 ± 0,5'e karşı 2,0 ± 0,7; p <0,03) anlamlı olarak daha yüksekti ve SVEF (16 ± 4'e karşı %27 ± 8, p <0,006) AKÖ grubunda anlamlı olarak daha düşüktü. Zirve VO2 (13,6 ± 7,4'e karşı 17,2 ± 5,8ml/kg/dk, p =0,138), kalp hızı değişkenliği (88 ± 51'e karşı 133 ± 59msn, p =0,059) ve QT dağılımı (88 ± 51'e karşı 90 ± 35msn, p =0,089) değerlerinde iki grup arasında anlamlı fark izlenmedi. Sonuç: Mevcut bulgular, ileri evre KKY olan hastalarda AKÖ riski açısından azalmış SVEF ve artmış kalp hızının istatiksel olarak anlamlı olduğunu, QT dispersiyonunun ise anlamsız öngörücü bilgi sağladığını göstermektedir.

Keywords

• kalp yetmezliği
• QT dispersiyonu
• prognoz
• mortalite

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