QT interval extracted from 30-minute short resting Holter ECG recordings predicts mortality in heart failure.

ABSTRACT

BACKGROUND: Prolonged repolarization duration is a significant total mortality (TM) predictor in post-myocardial infarction patients. AIM: We examined the clinical significance of QT interval that was extracted from a Short Resting Holter ECG (SRH ECG - 30-min duration) as a TM predictor in heart failure (HF) patients. METHODS: One hundred forty-five HF patients (male = 84%, mean age = 64 ± 12 years, mean LVEF = 33 ± 10%) underwent an SRH ECG recording for 30 min. These high-resolution ECG signals were analyzed and the QT interval was calculated and corrected according to the Fridericia formula. After 42.1 months, 26 patients died. RESULTS: Univariate analysis for Deceased and Living groups QTc455 ± 33 ms vs 441 ± 32 ms (p = 0.04), LVEF32 ± 10% vs 34 ± 9% (p < 0.5), Mean Heart Rate 73 ± 11 bpm vs 69 ± 12 bpm (p = 0.2), SDNN/HRV 45 ± 42 ms vs 41 ± 29 ms (p = 0.4), QRS 123 ± 26 ms vs 119 ± 29 ms (p = 0.5). Multivariate Cox regression analysis with model adjusted for QTc, Mean Heart Rate, LVEF, QRS, revealed that QTc-Fridericia interval was an independent TM predictor (H.R.1.017, 95% C.I. 1.003-1.030, p = 0.01). The cut-off point of 490 ms (90th percentile) in the same model presented HR 2.9 for TM (95%C.I. 1.066-7.882, p = 0.03). Kaplan Meier curves depicted a clear difference in survival between the two patients' groups (QTc Group≥490 ms vs QTc Group <490 ms). The curve diverge was important (log-rank, p = 0.02). CONCLUSION: A fast risk stratification approach with SRH ECG recording is an efficient method for flash evaluation of mortality risk in HF patients.