Effect of aprindine on heart rate variability indices in patients with ischemic heart disease

Background: Decreased heart rate variability indices (HRV) are associated w ith untoward outcome of patients with ischemic heart disease (IHD). Most cl ass I antiarrhythmic agents decrease HRV, but aprindine (a new class I anti arrhythmic agent) is reported to increase HRV in patients without ischemia. Hypothesis: The study was undertaken to determine whether aprindine might i ncrease HRV in patients with MD. Methods: To investigate the effect of aprindine on HRV in patients with MD, we performed 24-h ambulatory electrocardiogram (ECG) at the end of placebo and aprindine (60 mg daily) treatment phases on 38 patients with MD and at least isolated premature ventricular contractions (PVC). The study protoco l utilized a single blind, 4-week, placebo-controlled design. Heart rate va riability from ambulatory ECG included SDNN (ms), SDANN (ms), SD (ms), rMSS D (ms), pNN50 (%); frequency analysis of HRV consisting of total (ms, 0.01- 1.00 Hz), low (ms, 0.04-0.15 Hz), and high (ms, 0.15-0.40 Hz) components. Results: Study patients were divided into three groups according to the sev erity of IHD and antiarrhythmic efficacy of aprindine. Group 1 consisted of 15 patients with angina with single-vessel disease, and Group 2 was compos ed of 10 patients with either multivessel disease or post myocardial infarc tion; PVCs decreased in both groups as a result of aprindine treatment. Gro up 3 consisted of 13 patients who showed no decreased PVC after aprindine t reatment. RMSSD increased, and pNN50 and high-frequency spectra tended to i ncrease in Group 1, while SD, rMSSD, pNN50, and total and low-frequency spe ctra decreased in Group 3; no significant changes were observed in Group 2. Aprindine significantly augments vagal activity, as reflected by the incre ase of rMSSD, pNN50, and high-frequency spectra in mild MD. Conclusion: These salutary effects are less in more severe MD, but aprindin e does not aggravate HRV. Thus, if there are salutary effects on arrhythmia s and no proarrhythmic effects, aprindine could be prescribed to patients w ith IHD without concern about decreasing HRV.