Summary:Heart rate variability (HRV) has become a popular method for the studies of physiologic mechanisms responsible for the control of heart rate fluctuations. in which the autonomic nervous system appears to play a primary role. Depression of HRV has been observed in many clinical scenarios. including autonomic neuropathy. heart transplantation, congestive heart failure, myocardial infarction (MI), and othct cardiac and noncardiac diseases. However, it is important to realize that clinical implication of HRV analysis has been clearly recognized in only two clinical conditions: ( 1 ) as a ptcdictor of risk of arrhythniic events or sudden cardiac death after acute MI, and ( 2 ) as a clinical marker of evolving diabetic neuropathy. Recently, its role in evaluation and nianagenient of heart failure has also been recognized. It is pertinenl to recognize the limitations of HRV ;IS far as its clinical utility at present is concerned. The methodology of HRV had remoined poorly standardized until the recent publication of the Special Repon of the Task Force of ESC/NASPE. and thus has been presenting difficulty in comparing earlier existing data. Also, determination of the exact sensitivity. specificity, and predictive value of HRV, as well as the normal values of standard measures in the general population, still require further investigation before better standards can be set for existing and future clinical applications. This article review\ the major concepts of HRV measurements. their clinical relevance, and the recent advances in this field.

SummaryBackground: Use of herbs and nutritional supplements (known as naturoceuticals) is increasing in the USA, with about 50% of Americans taking naturoceuticals and spending over $10 billion per year for them. This raises concerns regarding their use instead of proven therapies, their side effects, and drug interaction potential.Hypothesis: The study sought to characterize cardiology patients who used supplements and to examine whether their use was diagnosis or doctor dependent, whether it affected patients' compliance, and what supplements were used.Methods: In all, 187 patients attending our cardiology clinic were interviewed, examined, and followed for up to 1 year. The users and nonusers of naturoceuticals were compared.Results: Supplements were used in 106 patients (an average of 3.1 naturoceutical per patient). There were no significant differences in their use by gender, age, primary care doctor specialty, or cardiovascular medications prescribed (except for statins). Patients with a history of myocardial infarction, coronary revascularization, hyperlipidemia, and a family history of coronary artery disease were more likely to use the supplements. Average low-density lipoprotein (106 vs. 108 mg/dl), average blood pressure (132/77 vs. 138/78 mmHg), and average hemoglobin (Hb)A1c (8.7 vs. 7.7%) showed no statistically significant differences between users and nonusers. Patients most commonly took multivitamins, vitamin E, vitamin C, vitamin B, folate, garlic, calcium, coenzyme Q10, and gingko.Conclusion: This study indicates that naturoceutical use is widespread among cardiovascular patients and it is difficult to predict clinically who the users are. Fortunately, according to our limited compliance measures, it appears that the naturoceutical use has not affected patients' compliance with tradi-

Ischemic heart disease is the most common underlying cause of congestive heart failure, and thus aspirin (acetylsalicylic acid [ASA]) and angiotensin-converting enzyme (ACE) inhibitors are commonly used together for treatment in this setting. The issue of possible attenuation of the effect of ACE inhibitors by ASA has been an area of intense debate. Currently, it is perceived that a significant part of the beneficial effect of ACE inhibitors is related to augmentation of bradykinin levels, which among other effects stimulate the release of prostacyclin. Aspirin, on the other hand, inhibits the production of prostacyclin by blocking cyclooxygenase. Prostaglandins play an important endogenous vasodilatory role and counteract the enhanced peripheral vasoconstriction state in congestive heart failure. Thus, the counteracting effect of ASA on the augmentation of prostacyclin synthesis by ACE inhibitors could result in a potential reduction of the beneficial effects of the ACE inhibitor's and could be of great importance. This article reviews reports from large clinical trials pertaining to this issue and relates their findings to the currently available theoretical bases for support of the counteracting effect of ASA on augmentation of prostacyclin synthesis by ACE inhibitors. The clinical implications of such an interaction are discussed.