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Aim-To investigate whether uncomplicated chronic coronary artery disease causes changes in heart rate variability and if so, whether the heart rate variability pattern is diVerent from that described in patients with acute myocardial infarction. Methods-Heart rate variability was studied in 65 patients with angina who had no previous myocardial infarcts, no other diseases, and were on no drug that could influence the sinus node. Results were compared with 33 age matched healthy subjects. The diagnosis of coronary artery disease in angina patients was established by coronary angiography in 58, by thallium scintigraphy in six, and by exercise test only in one. Patients and controls were Holter monitored 24 hours outside hospital, and heart rate variability was calculated in the frequency domain as global power (GP: 0.01-1.00 Hz), low frequency peak (LF: 0.04-0.15 Hz), high frequency peak (HF: 0.15-0.40 Hz), LF/HF in ms 2 , and in the time domain as SDNN (SD of normal RR intervals), SDANN (SD of all five minute mean normal RR intervals), SD (mean of all five minute SDs of mean RR intervals), rMSSD (root mean square of diVerences of successive normal RR intervals) (all in ms), and pNN50 (proportion of adjacent normal RR intervals diVering more than 50 ms from the preceding RR interval) as per cent. Results-The mean age in patients and controls was 60.4 (range 32-81) and 59.1 (32-77) years, respectively (NS), the male/female ratio, 57/65 and 24/33 (NS), and the mean time of Holter monitoring, 23.0 (18-24) and 22.8 (18-24) hours (NS). Mortality in angina patients was 0% (0/65) at one year, 0% (0/56) at two years, and 3% (1/33) at three years. Compared with healthy subjects angina patients showed a reduction in GP (p = 0.007), HF (p = 0.02), LF (p = 0.02), SD (p = 0.02), rMSSD (p = 0.01), and pNN50 (p = 0.01). No significant diVerence was found in RR, LF/HF, SDNN, or SDANN. Conclusions-Uncomplicated coronary artery disease without previous acute myocardial infarction was associated with reduced high and low frequency heart rate variability, including vagal tone. SDANN and SDNN, expressing ultra low and very low frequencies which are known to reflect prognosis after acute myocardial infarction, were less aVected. This is in agreement with the good prognosis in uncomplicated angina in this study. (Heart 2000;83:290-294)

The anti-ischemic and anti-anginal effects of continuous TEA are superior to those of conventional therapy in the treatment of refractory unstable angina.

Background: Reduced heart rate variability (HRV) after acute myocardial infarction (AMI) indicates poor prognosis. HRV in patients with uncomplicated coronary artery disease is reduced, and an association with poor prognosis has been suggested. The mechanism of the HRV reduction is not known, but ischemia is a possibility. Aim: To evaluate, in angina patients with no prior AMI, no other disease and drug-free, if complete revascularization and thus important reduction of ischemia by means of PTCA influences HRV. Patients and Methods: Twenty-four-hour Holter recordings were performed at baseline prior to PTCA in 48 patients with angina and in 41 age-matched healthy control subjects. The recording was repeated 1 and 6 months after complete revascularization. In addition, HRV was registered during controlled respiration in the supine and standing positions and during cold pressure test at baseline in all angina patients and controls and in 17 consecutive angina patients 6 months after PTCA. Results: Compared to controls, angina patients had a significantly reduced mean RR interval (p = 0.02), SD (p = 0.003), rMSSD (p = 0.03), pNN50 (p = 0.03), total power (p = 0.003), low- (p = 0.004) and high-frequency peak (p = 0.04), but normal SDNN, SDANN and LF/HF. One and 6 months after PTCA, 42/46 and 32/40 follow-up patients, respectively, were free of angina. Six months after PTCA, there was a significant recovery of vagal modulation seen in the frequency domain during controlled respiration, but only nonsignificant trends in HRV parameters analyzed over 24 h. Conclusion: Patients with uncomplicated angina had reduced HRV, mainly affecting vagal activity, but normal low frequency variability associated with mortality. Complete revascularization caused a partial normalization of vagal modulation indicating that ischemia may be one of but not the only mechanism of the HRV reduction in uncomplicated chronic coronary artery disease.

FUNCK, R.C., ET AL.: Atrial Overdriving Is Beneficial in Patients with Atrial Arrhythmias: First Results of the PROVE Study. The AF Prevention by Overdriving (PROVE) trial is an ongoing prospective study of the effectiveness of atrial overdrive pacing combined with an Automatic Rest Rate function in the pre vention of atrial arrhythmias. All patients who have received a Talent DR 213 pacemaker are eligible for enrollment into the study. After a 1-month monitoring period, the patients are divided into two groups. Group I includes patients with > 2 appropriate mode-switch (MS) episodes, or 1 MS episode of > 10 min utes, and/or > 300 atrial runs of > 5 beats/month. Group II includes all other patients. The number and duration of atrial arrhythmias are measured the pacemaker's Automatic Interpretation and Data Analy sis software (AIDA). Patients' quality-of-life is measured by a validated functional status questionnaire. After having been grouped, the patients are randomly assigned, in a crossover design, to standard DDDR or overdrive pacing + Rest Rate, each programmed for a 3-month period. Preliminary results in 78 pa tients show a 34% reduction in the mean number of MS, and a mean 48% shortening of the overall dura tion of the episodes by overdrive pacing + Rest Rate, achieved by a mean 84% prevalence of atrial pac ing. Overdrive pacing + Rest Rate was well tolerated and associated with a slight improvement in quality-of-life. (PACE 2000; 23[Pt. II]-.1891-1893 atrial fibrillation, overdrive atrial pacing, atrial arrhythmias