Self-reported influences of hopelessness, health literacy, lifestyle action, and patient inertia on blood pressure control in a hypertensive emergency department population.

BACKGROUND: In response to almost universally recorded poor blood pressure (BP) control rates, we developed a novel health paradigm model to examine the mindset behind BP control barriers. This approach, termed patient inertia (PtInert), is defined as an individual's failure to take responsibility for health conditions and proactive change. METHODS: PtInert was evaluated through a survey instrument conducted in 85 subjects with a prior history of hypertension seen in an emergency department. The survey tool encompassed the Wide Range Achievement Test 4, the brief symptom inventory, and a PtInert questionnaire. RESULTS: Fifty percent of patients reported slight psychological distress (psychosomatic > anxiety > depression), with 61% possessing hopelessness surrounding complications from high BP no matter their actions. An unanticipated finding was that patients who had a low reading proficiency (83.1 + 16.4 Wide Range Achievement Test 4 standard score) self-reported high levels of hypertension health literacy. Less than half of patients transferred this health literacy into lifestyle changes in diet, exercise, and medication adherence. Although patients felt that they could control their BP and frequently thought about better BP control, 55% of the subjects had uncontrolled hypertension (>140/90 mm Hg). CONCLUSION: Hypertensive patients visiting our emergency department perceive themselves to have adequate hypertension health-related literacy that was not transferred into hypertension health protective behavioral practices. Psychological distress and a sense of hopelessness surrounding BP control contribute to the lack of protective behavioral health practices. Further evaluations of PtInert methods to promote successful proactive change and adherence warrant further study.

Beneficial versus harmful effects of Angiotensin (1-7) on impulse propagation and cardiac arrhythmias in the failing heart.

INTRODUCTION: The presence of Angiotensin (1-7) (Ang 1-7) and ACE 2 in the ventricle of cardiomyopathic hamsters as well as the influence of Ang (1-7) on membrane potential, impulse propagation and cardiac excitability were investigated. METHODS: Histology and immunochemistry were used to demonstrate the presence of Ang (1-7) and ACE 2 in the ventricle of cardiomyopathic hamsters. Measurements of transmembrane potentials, conduction velocity and refractoriness were made using conventional intracellular microelectrodes. The influence of Ang (1-7) on sodium pump current was investigated in voltageclamped myocytes isolated from the ventricle. RESULTS: The results indicated the presence of Ang (1-7) and ACE 2 in myocytes of cardiomyopathic hamsters. Moreover,Ang (1-7) (10(-8) M) hyperpolarised the heart cell, increased the conduction velocity, and reduced transiently the action potential duration. The cardiac refractoriness was also increased by the heptapeptide, an effect in part reduced by an inhibitor of mas receptor. These findings indicate that Ang (1-7) has important antiarrhythmic properties. However, the beneficial effects of Ang (1-7) are dose-dependent because at higher concentration (10(-7) M) the heptapeptide elicited an appreciable increase of action potential duration and early-after depolarisations. Since losartan (10(-7) M) did not counteract this effect of the high dose of the heptapeptide, it is possible to conclude that activation of AT(1)-receptors is not involved in this effect of Ang (1-7). To investigate the mechanism of the hyperpolarising action of Ang (1-7) the influence of the heptapeptide on the sodium potassium pump current was studied in myocytes isolated from the ventricle of cardiomyopathic hamsters. The peak pump current density was measured under voltage clamp using the whole cell configuration. The results indicated that Ang (1-7) (10(-8) M) enhanced the electrogenic sodium pump, an effect suppressed by ouabain (10(-7) M). CONCLUSIONS: Ang (1-7) has beneficial effects on the failing heart by activating the sodium pump, hyperpolarising the cell membrane and increasing the conduction velocity. These effects as well as the increment of refractoriness indicate that Ang (1-7) has antiarrhythmic properties. At higher concentrations (10(-7) M), however, the heptapeptide induced early-after depolarisations which leads to the conclusion that an optimal generation of Ang (1-7) must be achieved to permit a protective role of Ang (1-7) on cardiac arrhythmias.

Increased hypothalamic angiotensin-(1-7) levels in rats with aortic coarctation-induced hypertension.

Since angiotensin (Ang) (1-7) injected into the brain blocked Ang II pressor actions in rats made hypertensive by aortic coarctation (CH), we examined systemic and tissue angiotensin peptide levels, specifically concentrating on the hypothalamic Ang-(1-7) levels. Plasma, heart and kidney isolated from CH rats showed increased levels of Ang I, Ang II and Ang-(1-7) compared with the normotensive group, with Ang II being the predominant peptide in heart and kidney. In the hypothalamus, equimolar amounts of Ang II and Ang-(1-7) were found in the sham group, whereas only Ang-(1-7) levels increased in CH rats. We conclude that aortic coarctation activates systemic and tissue renin-angiotensin system. The increased central levels of Ang-(1-7) in the CH rats suggest a potential mitigating role of this peptide in central control of the hypertensive process.

Hypertension-linked decrease in the expression of brain gamma-adducin.

Gene profiling data coupled with adducin polymorphism studies led us to hypothesize that decreased expression of this cytosolic protein in the brain could be a key event in the central control of hypertension. Thus, our objectives in the present study were to (1) determine which adducin subunit gene demonstrates altered expression in the hypothalamus and brainstem (two cardioregulatory-relevant brain areas) in two genetic strains of hypertensive rats and (2) analyze the role of adducins in neurotransmission at the cellular level. All three adducin subunits (alpha, beta, and gamma) were present in the hypothalamus and brainstem of Wistar Kyoto (WKY) and spontaneously hypertensive (SH) rats. However, only the gamma-adducin subunit expression was 40% to 60% lower in the SH rat compared with WKY rat. A similar decrease in gamma-adducin expression was observed in the hypothalamus and brainstem of the renin transgenic rat compared with its normotensive control. Losartan treatment of the SH rat failed to normalize gamma-adducin gene expression. A hypertension-linked decrease of gamma-adducin was confirmed by demonstrating a decrease in gamma-adducin expression in hypothalamic/brainstem neuronal cultures from prehypertensive SH rats. Neuronal firing rate was evaluated to analyze the role of this protein in neurotransmission. Perfusion of a gamma-adducin-specific antibody caused a 2-fold increase in the neuronal firing rate, an effect similar to that observed with angiotensin II. Finally, we observed that preincubation of neuronal cultures for 8 hours with 100 nmol/L angiotensin II caused a 60% decrease in endogenous gamma-adducin and was associated with a 2-fold increase in basal firing rate. These observations support our hypothesis that a decrease in gamma-adducin expression in cardioregulatory-relevant brain areas is linked to hypertension possibly by regulating the release of neurotransmitters.