Heart rate turbulence in patients with chronic heart failure.

BACKGROUND Heart rate turbulence (HRT) has been shown to predict the prognosis after myocardial infarction (MI), but its prognostic value in patients with chronic heart failure (CHF) has not yet been well established. AIM To evaluate HRT in patients with CHF and assess the prognostic significance of HRT in this group. METHODS The study group consisted of 82 patients with CHF and left ventricular ejection fraction (LVEF) <35%. All the patients underwent 24-hour Holter monitoring (HM). The heart rate variability (HRV) and HRT parameters were assessed using HRT view software. Two HRT parameters - turbulence slope (TS) and turbulence onset (TO), were calculated. We analysed the clinical course and survival during a two-year follow-up (mean 25+/-9 months). RESULTS The patients were divided into three groups according to the HRT parameters. Group 1 (23 patients) with both normal TO and TS (TO <0%, TS >2.5 m/s), group 2 (30 patients) with abnormal TO or TS, group 3 (29 patients) with abnormal TO and TS (TO >0% and TS <2.5 m/s). Patients from group 1 was significantly younger. There were no differences between patients in aetiology, treatment and the frequency of ventricular premature beats. Significant correlations between HRV and HRT parameters were observed. The correlation was the strongest between TS and SDNN and LF. During the follow-up 9 patients died and 15 were hospitalised for non-fatal infarction or worsening of CHF. Using a multivariate logistic regression model, it was shown that TS <2.5 ms/RR interval, and non-sustained ventricular tachycardia (VT) significantly increased the risk of a serious cardiac events in CHF patients. CONCLUSION HRT parameters are often abnormal in patients with CHF. An abnormal turbulence slope (TS) and VT episodes are significantly associated with increased risk of cardiac complications in CHF.