Prognostic value of heart rate turbulence and its relation to inflammation in patients with unstable angina pectoris

Heart rate turbulence (HRT) provided insights into cardiac autonomic function and predicted clinical outcome in patients with myocardial infarction. A relation between cardiac autonomic function and inflammation was shown in several clinical settings. To assess the prognostic impact of HRT and its relation with inflammation in patients with unstable angina pectoris (UAP), HRT parameters (turbulence onset [TO] and turbulence slope [TS]) were measured in 331 patients with UAP (age 66.4 +/- 10 years; 231 men) with premature ventricular complexes on electrocardiographic Holter monitoring. Total and cardiac mortality were assessed at the 6-month follow-up. The 6th (-1.52%) and 4th deciles (4.90 ms/RR) were the best prognostic cut-off values for TO and TS, respectively. TS <4.9 ms/RR was associated with hazard ratio (HRs) of 7.10 (95% confidence interval [CI] 2.68 to 18.8, p = 0.0001) and 8.02 (95% CI 2.73 to 23.6, p = 0.0002) for total and cardiac mortality, respectively. The same HRs for TO >-1.52% were 2.94 (95% CI 1.11 to 7.81, p = 0.03) and 3.33 (95% CI 1.13 to 9.79, p = 0.029), respectively. Patients with TO <-1.52% and TS >4.9 ms/RR showed very low risks of total and cardiac mortality (1.8% and 0.9%, respectively). TS <4.9 ms/RR was independently associated with total (HR 3.87, 95% CI 1.21 to 12.3, p = 0.02) and cardiac (HR 3.81, 95% CI 1.01 to 14.4, p = 0.048) mortality at multivariable analyses. Both TS (r = -0.29, p <0.001) and TO (r = 0.16, p = 0.005) showed significant correlation with serum C-reactive protein. Thus, HRT can be helpful for risk stratification of patients with UAP. The association between cardiac autonomic function and inflammation can be pathogenetically relevant in this clinical setting.