Clinical Covariates of Abnormal Heart Rate Turbulence in Coronary Patients

Background: The aim of this study is to evaluate the association between heart rate turbulence (HRT) parameters and clinical characteristics of coronary artery disease (CAD) patients.

Methods And Results: In 122 patients (mean age 62 +/- 9 years) with angiographically documented CAD, 24-hour Holter monitoring with HRT analysis was performed to evaluate turbulence onset (TO) and turbulence slope (TS). There was a significant correlation between TO and TS (P =-0.31; P < 0.001). According to quartile values, TO >or=-0.37% and TS <or= 4.25 ms/RR were considered as abnormal in this patient population. Average values of TO were higher and TS lower in patients over 60 years, in patients with a past history of myocardial infarction and in those with EF < 40%. Considering pharmacotheraphy, higher (better) values of TS were observed in patients on statins, nitrates, and beta-blockers while lower TS values were noted in patients on calcium blockers. Patients with abnormal parameters of HRT compared to group with normal HRT values were characterized by features of more advanced CAD: age over 60 years (75% vs 49%), past history of MI (75% vs 64%), and EF < 40% (25% vs 3%). Multivariate analysis revealed age > 60 years (OR 1.27; P = 0.002) and EF < 40% (OR 1.39; P = 0.001) as independent clinical factors associated with abnormal HRT parameters.

Conclusions: HRT parameters are influenced by clinical characteristics and pharmacotherapy of studied patients with TS more than abnormal TO depending on clinical characteristics of patients. Advanced age, prior myocardial infarction and left ventricular dysfunction are key factors influencing values of HRT parameters.