Differences in heart rate turbulence between patients with coronary artery disease and patients with ventricular arrhythmias but structurally normal hearts.

The term "heart rate turbulence" (HRT) indicates the physiologic changes in the sinus cycle that follow a ventricular premature complex; impaired HRT denotes abnormalities in cardiac autonomic function. To investigate whether HRT is impaired in patients with stable coronary artery disease (CAD), we studied 29 patients with documented CAD and frequent (>/=30/hour) ventricular premature complexes on Holter monitoring and 31 patients with frequent ventricular arrhythmias but normal hearts (NH-VA). HRT and heart rate variability analyses were analyzed on 24-hour Holter recordings. HRT variables differed significantly between the 2 groups (turbulence onset -0.20 +/- 1.7% vs -0.67 +/- 2.2%, p = 0.00001; turbulence slope 2.83 +/- 1.9 vs 10.83 +/- 7.4 ms/RR, p = 0.0001 in patients with CAD and NH-VA, respectively). The difference was independent of a history of previous myocardial infarction, left ventricular function, and age. Top quartile turbulence onset values (>-0.26%) and bottom quartile turbulence slope values (<2.12 ms/RR) had similar predictive power in discriminating between patients with CAD and NH-VA (positive predictive value 86.7%, negative predictive value 64.4% for both). Among heart rate variables, bottom quartile SD of all RR intervals values (<96.3 ms) only had the same power of HRT variables in discriminating between patients with CAD and NH-VA. Thus, our data show that HRT variables are impaired in patients with CAD patients versus those with NH-VA, indicating abnormalities in the control of short-term cardiac autonomic mechanisms resulting in decreased vagal activity with likely predominant sympathetic activity.