Coronary heart rate

One of the most important research advances since World War II is the delineation of the chief mechanism of the etiologic effect of dietary lipid on atherogenesis. This has been the demonstration - as illustrated in the last three figures - that populations differing in habitual intake of saturated fat and cholesterol also differ markedly in serum cholesterol levels, i.e., interpopulation levels of these two sets of variables are highly correlated. So also are dietary saturated fat-cholesterol intake and coronary heart rates, and serum cholesterol level and coronary heart disease rates. 

Nicorandil. Nicorandil is a potassium channel opener that can lower blood pressure 21, 20, and 29 mm Hg after single oral doses of 10, 20, and 30 mg, respectively (250). There are no significant changes ia heart rate. Headache is the primary side effect. Nicorandil has potent coronary vasodilator effects. It causes sustained vasodilation of arteriolar resistance and venous capacitance blood vessels, thus reduciag cardiac preload and aftedoad. 

We examined the effects of selective activation of histamine Hj receptors on coronary hemodynamics in two groups patients with atypical chest pain and normal coronary arteries, and patients with vasospastic angina [48]. Selective Hj receptor stimulation was achieved by infusing histamine intravenously (0.5 pg/kg/min) for 5 min after pretreatment with cimetidine to antagonize the H2 receptors. Heart rate was kept constant (100 beats/min) by coronary sinus pacing. 

In a third study the time course of the effects of intravenous and intracoronary injections of cysteinyl leukotrienes on metabolic parameters and systemic and coronary hemodynamics was examined in patients with normal coronary arteries [32]. LTD4 (3 nmol, injected into the left coronary artery) induced an early (20 s), transient fall in mean arterial pressure paralleled by rises in heart rate and plasma levels of epinephrine and norepinephrine, all of which had returned to baseline by 10 min. CVR rose at 10 and 15 min and myocardial oxygen extraction at 15 min. Thus, small doses of cysteinyl leukotrienes may induce both an early, transient fall in mean arterial pressure, with secondary sympathoadrenergic activation, and a later increase in small coronary arteriolar resistance. 

Contraindications are the same as for immunotherapy for inhalant allergy, but are relative in nature because of the life-saving potential of venom immunotherapy. Elderly patients, especially with preexisting cardiovascular disease, are at a high risk to develop severe or even fatal anaphylaxis [26]. Therefore, venom immunotherapy is often recommended in patients over 50-60 years of age. Since (3-blocker treatment is associated with a significantly increased survival rate in patients with coronary heart... 

YuXC et al. (2001) Cardiac effects of the extract and active components of Radix stephaniae tetrandrae II. Myocardial infarct, arrhythmias, coronary arterial flow and heart rate in the isolated perfused rat heart. Life Sci 68(25) 2863-2872... 

Gailis, M. and Nguyen, M.-H. (1975). The effect of sulphydryl reagents on the heart rate and coronary flow of the isolated perfused guinea pig heart. Arch. Int. Pharmacodyn. Ther. 218, 19-28. 

Increased oxygen demand secondary to increased heart rates and blood pressure has been hypothesized to lead to myocardial infarction (especially in patients with fixed coronary disease) and/or ventricular arrhythmias. In patients with no history of cardiac disease, cocaine is thought to induce acute isehemie complications via vasospasm of the coronaries (Ascher et al. 1988). In addition, Virmani et al. (1988) have reported a 20 percent incidence of myocarditis thought to be secondary to accumulated microvascular injuries. 

The results were that income inequality was strongly associated with lack of social trust, and that states with high levels of social mistrust had higher age-adjusted rates of total mortality (level of social trust explained 18% of variance in total mortality, under their regression). Lower levels of social trust were associated with higher rates of most major causes of death, including coronary heart disease, malignant neoplasms, cerebrovascular disease, unintentional injury, and infant mortality. 

The benefits result from blockade of //j receptors in the myocardium, which reduces heart rate, myocardial contractility, and BP, thereby decreasing myocardial oxygen demand. The reduced heart rate increases diastolic time, thus improving ventricular filling and coronary artery perfusion. 

A volume of 100 pmol P cyclo(Cys-Ile) reduced heart rate by 12.14% (P= 0.0022) 30 min after perfusion with the drug. Cyclo(Cys-Val) reduced the heart rate by 8.11% (P= 0.0021). Cyclo(Cys-Ile) reduced coronary flow rate by 92.34% (P= 0.00012) 30 min after perfusion with the drug, while cyclo(Cys-Val) reduced coronary flow rate by 84.05% (P= 0.00014). 

During ventricular pressure experiments the heart rate was kept constant by pacing. Even with the heart rate constant, both DKPs displayed a decrease in coronary flow. Cyclo(Cys-Ile) was found to decrease coronary... 

An extension of the Seven Countries Study, by Ancel Keys and colleagues, indicated the particular importance of the flavonoids. During the study, which was reported in 1980, random samples of the food eaten by the participants were taken and stored for future analysis. When this was done, it was found that the average intakes of the antioxidants vitamin E, P-carotene and vitamin C were not related to the 25-year coronary heart disease mortality rates. In contrast, the intake of flavonoids was inversely related to the mortality. 

The subsequent conversion of HMG-CoA into MVA involves a two-step reduction of the thioester group to a primary alcohol (see Section 7.11), and provides an essentially irreversible and rate-limiting transformation. Drug-mediated inhibition of this enzyme, HMG-CoA reductase (HMGR), can be used to regulate the biosynthesis of the steroid cholesterol. High levels of blood cholesterol are known to contribute to the incidence of coronary heart disease and heart attacks. 

Pharmacology Sympathomimetic agents produce -adrenergic stimulation (vasoconstriction), - -adrenergic stimulation (increase myocardial contractility, heart rate, automaticity, and AV conduction), and 2-adrenergic activity (peripheral vasodilation). Dopamine also causes vasodilation of the renal and mesenteric, cerebral, and coronary beds by dopaminergic receptor activation. 

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