Heart Rate Systolic Blood Pressure Research Articles

Effects of Foot-Massage on Mood and Autonomic Nervous System and the Interaction with Personality

Massage is often used to reduce psychological distress or to improve local circulation, but, the effects of massage are neither stable nor consistent. The purpose of this study was to evaluate effects of foot-massage on mood and autonomic nervous system in highly stressed students, and the interaction with personality. We selected highly stressed students by scores of daily hassles scale and profile of mood states (POMS). We employed POMS and visual analogue scale to assess mood, and employed heart rate variability, systolic and diastolic blood pressure (BP), and baroreflex sensitivity to assess autonomic nervous function. Repeated measures analysis of variance (ANOVA) revealed increase of vigor and comfortableness, and decrease of diastolic BP after foot-massage. To evaluate the interaction with personality, repeated measures ANOVA was applied to two groups (low- and high-) divided by the score of clinical scale of Minnesota Multiphasic Personality Inventory (MMPI). High-Pa group (considered to be sensitive in human relationships) showed significant decrease of tension-anxiety after the massage,but low-Pa did not. Low-Si group (considered to be socially active) showed significant decrease of angerhostility and fatigue after the massage, but high-Si did not. And low-Ma group (considered to be temperate and adjusting slowly) showed remarkable decrease of diastolic BP after the massage, but high-Ma did not. These results suggest that foot-massage would generally raise vigor and comfortableness, and decrease diastolic BP, however, the effects would be different from person to person, and beneficial effects to reduce tension-anxiety, anger-hostility and fatigue can be expected dependent on their personality.

Abstract 498: Increased Blood Pressure Variability and Baroreflex Impairment in Patients With End-stage Renal Disease Undergoing Hemodialysis

Background: Patients with end-stage renal disease (ESRD) undergoing hemodialysis are susceptible to the development of autonomic dysfunction, which is associated with an increased risk of sudden death. Experimental and clinical evidence suggest a crucial role of autonomic dysfunction for both, the progression of renal disease and for the high rate of cardiovascular events in these patients. In the present study, we evaluated the heart rate variability (HRV), the blood pressure variability (BPV) and the baroreflex sensitivity (BRS) in ESRD patients undergoing hemodialysis and normal controls. Methods: Nine ESRD patients undergoing hemodialysis (mean age 53.4±10.2 years, 4 male) and nine age-matched healthy controls (mean age 52.8±10.2 years, 4 male) were assessed. Non−invasive curves of blood pressure (BP) were recorded continuously (Finometer ®) for 10 minutes, at rest, in the supine position. The heart rate variability (HRV) and systolic blood pressure variability (BPV) were estimated in the time and frequency domain (spectral analysis). The BRS was quantified by alpha index. Statistical analyzes were performed by Student's t test and the results were expressed as mean ± standard deviation. Results: ESRD patients presented lower HRV in time domain than healthy controls (SDNN: 25.8±10.7 vs. 44.6±11.7 ms, p<0.01; VAR NN: 768.3±607.4 vs. 2113.9±1261.6 ms 2 , p=0.01). All frequency domain analyzed indexes, i.e., total power (361.9±297.0 vs. 1227.2±696.3 ms 2 , p<0.01), high-frequency (181.8±128.7 vs. 358.7±179.8 ms 2 , p=0.047), low-frequency (55.1±44.2 vs. 444.6±389.9 ms 2 , p=0.02) and very-low-frequency (72.5±75.1 vs. 279.2±119.5 ms 2 , p<0.01) of HRV were lower in ESRD patients. The BPV was higher in ESRD patients when compared to controls (VAR PAS: 98.4±72.0 vs. 35.4±21.4 ms 2 , p=0.03) and BRS was lower in ESRD patients (alpha index: 4.34±3.05 vs. 7.56±2.50 ms/mmHg, p<0.02). Conclusion: ESRD patients undergoing hemodialysis presents reduced HRV, increase in BPV and reduced baroreflex sensitivity. These impairments may be associated with mortality in ESRD.

Short-term outcomes in patients with Takotsubo cardiomyopathy: an age- and gender matched comparison to patients with acute coronary syndrome

Purpose: Clinical presentation of Takotsubo cardiomyopathy (TTC) mimics acute coronary syndromes (ACS). While ACS is a life-threatening condition, TTC is usually regarded as a non-fatal cardiomyopathy with a favorable long-term outcome. Severe complications have been reported in patients with TTC in the acute stage, however systematic data are lacking. Therefore, the aim of the present study was to assess the short-term outcome in patients with TTC compared to patients with ACS. Methods: 584 patients were included in the present study. 292 consecutive patients with TTC were identified according to the Mayo Clinic Diagnostic criteria and compared to an age- and gender matched control population with ACS. Medical records were evaluated from the International Takotsubo-Registry at the University Hospital of Zurich and the Zurich Acute-Coronary-Syndrome Registry from 2002-2012. Clinical profile and in-hospital mortality as well as cardiogenic shock rate were analyzed. Results: On admission, patients with TTC presented with a significantly higher heart rate (p<0.001) and lower systolic blood pressure compared to patients with ACS (p=0.02). In addition, left ventricular ejection fraction was significantly reduced (p<0.001) and end-diastolic pressure elevated (p=0.006) in comparison to patients with ACS. We did not observe any differences in resuscitation and catecholamine administration between the two groups on acute presentation (p=n.s). The prevalence of cardiogenic shock (TTC 12% vs. ACS 10.3%, p=n.s.) and death (TTC 4.1% vs. ACS 4.1%, p=n.s.) were not significantly different between the two groups. Conclusion: Our study demonstrates that TTC is a potentially life-threatening disease with the same short-term outcomes compared to patients with ACS. Therefore, intensive monitoring and early treatment must be considered in such patients.

EPLERENONE ATTENUATES MYOCARDIAL FIBROSIS IN THE ANGIOTENSIN II-INDUCED HYPERTENSIVE MOUSE: INVOLVEMENT OF OSTEOPOTIN INDUCED BY NADPH OXIDASE

EPLERENONE ATTENUATES MYOCARDIAL FIBROSIS IN THE ANGIOTENSIN II-INDUCED HYPERTENSIVE MOUSE: INVOLVEMENT OF OSTEOPOTIN INDUCED BY NADPH OXIDASE

RESEACH ON THE EXERCISE TESTING COMPARE TO THE RESULT OF CORONARYGRAPHY IN PATIENTS WITH CHEST PAIN

Objective and Materials: The research was conducted on 60 patients with chest pain (average age: 56.67 ± 9.28, oldest is 79 and youngest is 36). Patients were applied exercise testing for orient diagnose coronary disease, especially for assessment the sensitivity and the specific of ST/R rate in diagnosing cardiac muscle local ischemia and to compare with the result of coronarygraphy. Results: There were 17 patients with possitive exercise testing result (28.3%) and possitive exercise testing result (71.7%). The risk factors of patients with chest pain took 88.3%, in which serum lipid disorder was 76.7%, hypertension was 60.0%, obesity (48.3%), smoking (40.0%) and diabetes (23.3%). There was no statistic significant difference between coronarygraphy(-) and coronarygraphy(+), p&gt;0.05. There was statistic significant difference about heart rate parameters, exercise capacity, double multiply (HRxTA), HR recovery and systolic blood pressure between two groups of specific chest pain and nonspecific chest pain, p&lt;0.05. There was statistic significant difference between the index of exercise testing and coronarygraphy result, p&lt;0.05. Exercise testing by bicycle in diagnosing coronary disease has the sensitivity, the specific, the accuracy, positive forecast value and negative forecast value was 59.09%, 89.47%, 78.33%, 76.47%, 79.07%, respectively. The R wave in diagnosing coronary disease has the sensitivity, the specific, the accuracy, positive forecast value and negative forecast value was 77.27%, 23.68%, 43.33%, 36.96%, 64.29%, respectively. The rate ST/R in diagnosing coronary disease has the sensitivity, the specific, the accuracy, positive forecast value and negative forecast value was 50.00%, 94.74%, 78.33%, 84.62%, 76.60%, respectively.

Hemodynamic Changes During the Anhepatic Phase in Pediatric Patient With Biliary Atresia Versus Glycogen Storage Disease Undergoing Living Donor Liver Transplantation

ObjectiveThe aim of this study was to compare the hemodynamic changes caused by clamping of the inferior vena cava and portal vein in biliary atresia (BA) versus glycogen storage disease (GSD) patients undergoing living-donor liver transplantation (LDLT) without venovenous bypass. MethodsWe reviewed retrospectively the anesthesia charts of pediatric LDLT patients. Age, weight, height, blood loss, blood product use and fluid replacement between groups were compared with Mann-Whitney test, and systolic blood pressure (SBP), heart rate (HR), central venous pressure (CVP) before clamping of the inferior vena cava, and 4 measurements during anhepatic phase and 5 minutes after reperfusion were compared with analysis of variance. ResultsOne hundred four BA patients (GI) and 12 GSD patients (GII) showed mean total blood loss among GI to be more than among GII, but the blood products and crystalloids infused during the operation were not significantly different. The changes of SBP, HR, and CVP after clamping of the IVC were significantly different between groups. CVP of GII was lower than GI, indicating that venous return among GII was more affected, subsequently showing lower SBP and higher HR. ConclusionsTotal clamping of the inferior vena cava resulted a greater decrease in CVP in GII with subsequently lower SBP and faster HR compared with GI.

Diet and exercise training reduce blood pressure and improve autonomic modulation in women with prehypertension

Despite mortality from heart disease has been decreasing, the decline in death in women remains lower than in men. Hypertension (HT) is a major risk factor for cardiovascular disease. Therefore, approaches to prevent or delay the onset of HT would be valuable in women. Given this background, we investigated the effect of diet and exercise training on blood pressure (BP) and autonomic modulation in women with prehypertension (PHT). Ten women with PHT (39 ± 6 years, mean ± standard deviation) and ten with normotension (NT) (35 ± 11 years) underwent diet and exercise training for 12 weeks. Autonomic modulation was assessed through heart rate (HR) and systolic BP (SBP) variability, using time and frequency domain analyses. At preintervention, women with PHT had higher SBP (PHT: 128 ± 7 vs. NT: 111 ± 6 mmHg, p < 0.05) and lower HR variability [standard deviation of normal-to-normal beats (SDNN), PHT: 41 ± 18 vs. NT: 60 ± 19 ms, p < 0.05]. At post-intervention, peak oxygen consumption and muscular strength increased (p < 0.05), while body mass index decreased in both groups (p < 0.05). However, SBP decreased (118 ± 8 mmHg, p < 0.05 vs. preintervention) and total HR variability tended to increase (total power: 1,397 ± 570 vs. 2,137 ± 1,110 ms(2), p = 0.08) only in the group with PHT; consequently, HR variability became similar between groups at post-intervention (p > 0.05). Moreover, reduction in SBP was associated with augmentation in SDNN (r = -0.46, p < 0.05) and reduction in low-frequency power [LF (n.u.); r = 0.46, p < 0.05]. In conclusion, diet and exercise training reduced SBP in women with PHT, and this was associated with augmentation in parasympathetic and probably reduction in sympathetic cardiac modulation.

Vital signs and estimated blood loss in patients with major trauma: Testing the validity of the ATLS classification of hypovolaemic shock

Aim The Advanced Trauma Life Support (ATLS) system classifies the severity of shock. The aim of this study is to test the validity of this classification. Methods Admission physiology, injury and outcome variables from adult injured patients presenting to hospitals in England and Wales between 1989 and 2007 and stored on the Trauma Audit and Research Network (TARN) database, were studied. For each patient, the blood loss was estimated and patients were divided into four groups based on the estimated blood loss corresponding to the ATLS classes of shock. The median and interquartile ranges (IQR) of the heart rate (HR) systolic blood pressure (SBP), respiratory rate (RR) and Glasgow Coma Score (GCS) were calculated for each group. Results The median HR rose from 82 beats per minute (BPM) in estimated class 1 shock to 95 BPM in estimated class 4 shock. The median SBP fell from 135 mm Hg to 120 mm Hg. There was no significant change in RR or GCS. Conclusion With increasing estimated blood loss there is a trend to increasing heart rate and a reduction in SBP but not to the degree suggested by the ATLS classification of shock.

Testing the validity of the ATLS classification of hypovolaemic shock

Aim The Advanced Trauma Life Support system classifies the severity of shock. The aim of this study is to test the validity of this classification. Methods Admission physiology, injury and outcome variables from adult injured patients presenting to hospitals in England and Wales between 1989 and 2007 and stored on the Trauma Audit and Research Network (TARN) database, were studied. Patients were divided into groups representing the four ATLS classes of shock, based on heart rate (HR) systolic blood pressure (SBP), respiratory rate (RR) and Glasgow Coma Score (GCS). The relationships between variables were examined by classifying the cohort by each recorded variable in turn and deriving the median and interquartile range (IQR) of the remaining three variables. Patients with penetrating trauma and major injuries were examined in sub-group analyses. Results In blunt trauma patients grouped by HR, the median SBP decreased from 128 mm Hg in patients with HR < 100 BPM to 114 mm Hg in those with HR > 140 BPM. The median RR increased from 18 to 22 bpm and the GCS reduced from 15 to 14. The median HR in hypotensive patients was 88 BPM compared to 83 BPM in normotensive patients and the RR was the same. When grouped by RR, the HR increased with increasing RR but there were no changes in SBP. Conclusion In trauma patients there is an inter-relationship between derangements of HR, SBP, RR and GCS but not to the same degree as that suggested by the ATLS classification of shock.

Hemodynamic variables during stress testing can predict referral to early catheterization but failed to show a prognostic impact on emerging cardiac events in patients aged 70 years and older undergoing exercise 99mTc-sestamibi myocardial perfusion scintigraphy

The aim of the present study was to evaluate the prognostic value of hemodynamic variables during ergometric stress testing for (99m)Tc-sestamibi myocardial perfusion scintigraphy (MPS) as compared to several patient-related variables and MPS results with regard to referral to early coronary angiography (<3 months after MPS; CA) as well as cardiac event (CE) free survival in a study population aged > or =70 years. About 90 patients aged > or =70 years (74.5 +/- 3.6 years) who underwent ergometric stress/rest MPS were included in this study. About 19 hemodynamic variables during stress testing were assessed. Semiquantitative visual interpretation of MPS images were performed and Summed-Stress-(SSS), Summed-Difference-, and Summed-Rest-Scores were calculated. Emerging CE comprised myocardial revascularization and -infarction as well as cardiac-related death. Multivariate logistic regression analyses were performed for evaluation of independent prognostic impact of hemodynamic-, MPS- and clinical-variables with regard to referral to early catheterization as well as emerging CE. Kaplan-Meier survival- and log rank analyses were calculated for assessment of CE free survival. History of CAD (Odds ratio; OR: 99.3), low rest heart rate (OR: 14.9) and low peak systolic blood pressure (OR: 15.4) during ergometric stress testing as well as pathological SSS (OR: 48.4) were significantly associated with referral to CA. History of ischemic ECG (OR: 4.7) and pathological SSS (OR: 3.7) independently predicted emerging CE and were associated with a lower CE free survival. In patients aged > or =70 years, CA is independently predicted by clinical variables, pathological results of MPS and hemodynamic variables. In contrast, hemodynamic response to stress testing failed to show any predictive impact on emerging CE.

Alcohol's Role on the Reliability of Clinical Examination to Rule Out Pelvic Fractures

The objective of this study was to determine if clinical examination accurately ruled out pelvic fractures in intoxicated patients sustaining blunt trauma A prospective comparison of intoxicated (blood alcohol level [BAL] greater than 0.08 g/dL) to nonintoxicated (BAL less than 0.08 g/dL) patients sustaining blunt trauma was performed between February 2004 and March 2007. Clinical factors were compared and subset analysis performed in which patients with factors known to compromise the clinical examination were excluded. Two hundred ninety-six intoxicated patients were compared with 1071 nonintoxicated patients. Intoxicated patients were younger and more often male. Intoxicated patients had a higher heart rate (97.1 beats/min +/- 17.9 vs 91.4 beats/min +/- 18.7, P < 0.0001) and lower systolic blood pressure (136.2 mmHg +/- 21.2 vs 141.9 mmHg +/- 26.6, P = 0.0005) than nonintoxicated patients. Intoxicated patients had a lower incidence of pelvic fracture (6.1 vs 10.6%). In subset analysis, the majority of the intoxicated patients did not have exclusion factors on examination and could be evaluated (66.6%). There were eight pelvic fractures diagnosed in this group and no missed injuries on clinical examination (sensitivity 100%). Clinical examination was not compromised by intoxication. Routine pelvic x-rays are not needed in the alert, intoxicated patient sustaining blunt trauma.

Effects of chronic smoking on exercise tolerance and on heart rate-systolic blood pressure product in young healthy adults

Smoking is a major cause of cardiovascular disease and mortality. Smoking-related deaths in Greece account for 23%, whereas 41% of young Greeks are smokers, the highest percentage in Europe. The purpose of this study was to examine the effects of chronic smoking on the rate-pressure product and exercise tolerance in young, healthy male smokers. Forty-two smokers and 51 nonsmokers were selected from a population of 543 students based on their age, sex, body mass index, physical fitness, smoking habit and health status. All participants were tested with the standard Bruce treadmill protocol. The rate-pressure product was obtained at rest and during exercise at a given submaximal workload. The evaluation of exercise tolerance was based on peak workload achieved and maximal exercise test duration. The smokers had a higher rate-pressure product at rest (P<0.001) due to their higher resting heart rate (P<0.001). Resting values of blood pressure did not differ significantly between the two groups. During exercise, smokers had a greater rate-pressure product (P<0.001), mainly due to their significantly higher systolic blood pressure (P=0.008). The smokers had a higher submaximal heart rate (P=0.005), but the differences in heart rate between groups were reduced for smokers during exercise when compared to rest. The smokers' exercise tolerance was impaired and their maximal exercise test duration time was significantly shorter (P<0.001). Chronic smoking was found to affect young male smokers' cardiovascular fitness, impairing the economy and decreasing the capacity of their circulatory system.

‘Warm-up’ phenomenon in diabetic patients with stable angina treated with diet or sulfonylureas

Classic sulfonyloureas (SUs) are known to attenuate ischaemic preconditioning. Gliclazide is an SU agent believed to be more protective. We assessed the effects of diet, glibenclamide, or gliclazide on the warm-up effect in type 2 diabetic patients with stable angina. The study group consisted of 64 men, aged 54+/-5 years: 17 patients without diabetes (G I) and 47 diabetic patients: 16 patients treated with glibenclamide (G II), 16 with gliclazide (G III) and 15 patients treated with diet (G IV). After the baseline positive exercise test (ET1), all patients reexercised after 30-min rest (ET2). We analysed exercise duration (ED, s), time to 1 mm ST depression (T-STD, s), max STD (mm), heart rate-systolic blood pressure product at 1 mm STD, or ischaemic threshold (mmHg/min x 100) and the total ischaemic time (s). In G I, all analysed variables improved significantly during ET2 relative to ET1. Glibenclamide (G II) completely abolished the protective effect of exercise-induced ischaemia because only ED increased during ET2 (431 vs. 451, P<0.05). In G III, however, ED (486 vs. 537, P<0.001), T-STD (364 vs. 388, P<0.05) and max STD (2.5 vs. 2.0, P<0.05) improved significantly during ET2, whereas ischaemic threshold and total ischaemic time did not (PNS). In G IV, similar to G I, all variables improved significantly during ET2 relative to ET1. Warm-up effect is preserved in diabetic patients with stable angina treated with diet, partially preserved in gliclazide-treated and abolished in glibenclamide-treated patients.

Baroreflex mechanisms in major depression

Background Recent studies have shown that depressive disorder is associated with impaired baroreceptor or baroreflex sensitivity, which is proposed to be a predisposing factor for sudden death in patients with manifest cardiac disease. These studies have not evaluated the afferent and efferent components of the cardiac baroreflex loop or other baroreflex mechanisms that regulate target processes (cardiac metabolism and blood pressure variability) related to the impairment. The objective of this study was to gain more insight into autonomic functioning in depressive disorder to more fully examine the potential basis for increased cardiac mortality. Methods The subjects were 28 women and men with unipolar major depression who were taking antidepressant medications and who were in partial remission and free of cardiovascular or other serious disease, and 28 healthy control subjects matched for sex, age, and ethnicity. The two samples were compared for negative affective dispositions (anger expression, hostility, defensiveness, anxiety), spontaneous (closed-loop) baroreflex activity, heart rate, heart rate variability, systolic blood pressure, and heart rate-systolic blood pressure double product under resting conditions. Results Depressed patients showed a general disposition to anger suppression coupled with higher hostility and anxiety, and lower defensiveness. The patients showed higher general sympathetic activity (high levels of blood pressure, low-frequency heart rate variability) and lower parasympathetic-related activity (high heart rate and reduced high frequency heart rate variability) with affected cardiac metabolism estimated by the double product. Depressed patients had lower baroreflex sensitivity related to a higher gain of the afferent component of the baroreflex without respective gain adjustment of its efferent component (reflex gain ‘de-afferentation’). It was coupled with a compensatory higher number of effective baroreflex reactions (reflex gating ‘re-afferentation’). Antidepressant agents and depressed mood had additional independent effects on baroreflex sensitivity through the efferent component of the cardiac baroreflex loop. Conclusions The data indicate that different baroreflex components and mechanisms may be impaired in patients with depression and may contribute to their increased cardiac risk.

Reply to Kargar and Aazami

We thank Kargar and Aazami [1] for their interest in our recent article on flow dynamics and wall shear stress (WSS) in the left internal thoracic artery (LITA) [2]. In this study we show that the LITA has a marked adaptability to flow dynamics with a clear propension to adequate WSS and crosssectional area to flow requirements. Two modifications take place into proximal LITA used as a composite Y-graft: (1) a ‘passive’ increase in blood flow due to the lower resistance of the parallel vascular circuit represented by the Y-graft, as expressed by the Kirchoff’s 2nd law, and (2) an ‘active’ increase of proximal LITA diameter related to the higher average peak velocity and blood flow that stimulate the synthetic and secretory functions of endothelial cells, modulating the production of nitric oxide and endothelin-1 to obtain proximal LITA dilatation. Finally also the flow pattern could have a role in the production of vasoactive substances by vascular endothelial cells, presenting the proximal part of LITAY-graft a diastolic-predominant peak of flow velocity, probably related to the reduced vascular resistance of the parallel vascular circuit. In conclusion our study shows that in composite Y-graft the proximal LITA is able to actively adapt its dimension to the flow demand, probably through the release of endothelial vasoactive mediators, consequence of higher values of WSS. This process of adaptation begins immediately after the operation because of the passive increase of blood flow due to the lower vascular resistance of the Y-graft system. Kargar and Aazami seem to be skeptical about the adaptability of the LITA to increased myocardial blood flow requirements. However we have shown that soon after the operation the LITA used as a Y-graft can significantly increase blood flow in response to conditions of increased MVO2, keeping normal the O2 supply-to-demand ratio. We obtained these data measuring blood flow in Y-graft both at rest and during atrial pacing at the 85% of the patient age-predicted maximum, considering the heart rate-systolic blood pressure product an indirect index of MVO2 [3]. Both the afore mentioned functional data and the favourable clinical results coming from LITA used as a Y-graft [4] should comfort Kargar and Azami about the safety and afficacy of the LITA in Y-graft configuration. We thank again Kargar and Aazami for their interest in our paper.

Effect of repetitive hypoxic apnoeas on baroreflex function in humans

Baroreflex function is impaired in patients with obstructive sleep apnoea. We tested the hypothesis that short-term exposure to repetitive hypoxic apnoeas (RHA) produces prolonged impairment in baroreflex function. Baroreflex function was determined using the modified Oxford technique in 14 subjects (26 +/- 1 years). Baroreflex sensitivity (BRS) was quantified from the R-R interval-systolic blood pressure (BP; cardiovagal BRS), heart rate-systolic BP (HR BRS) and muscle sympathetic nerve activity (MSNA)-diastolic BP (sympathetic BRS) relations. RHA involved subjects performing repetitive end-expiratory apnoeas (20 s) every minute for 30 min during intermittent hypoxia to accentuate oxygen desaturation. After RHA, BP and MSNA at rest were elevated. BRS was measured approximately 7 (Post 1), approximately 30 (Post 2) and approximately 50 min (Post 3) after RHA to provide insight into the temporal pattern of responses. Cardiovagal BRS (16.8 +/- 1.3, 16.5 +/- 1.6, 17.6 +/- 2.0 and 17.4 +/- 1.5 ms mmHg(-1) for Pre, Post 1, Post 2 and Post 3, respectively), HR BRS (-1.1 +/- 0.1, -1.1 +/- 0.1, -1.3 +/- 0.1 and -1.4 +/- 0.1 beats min(-1) mmHg(-1)) and sympathetic BRS (-4.5 +/- 0.6, -4.4 +/- 0.7, -3.7 +/- 0.5 and -4.7 +/- 1.0 arbitrary units (au) beat(-1) mmHg(-1)) were unchanged by RHA. In contrast, the operating points of the baroreflexes were shifted rightward (to higher levels of BP) and upward (to higher levels of heart rate and MSNA) after RHA (P < 0.05). Time control studies performed in five additional subjects showed no change in any of the measured variables over time. Collectively, these data indicate that short-term exposure to RHA shifts ('resets') the baroreflex stimulus-response curve to higher levels of BP without influencing BRS for extended periods of time.

Androgen Receptor Gene Knockout Male Mice Exhibit Impaired Cardiac Growth and Exacerbation of Angiotensin II-induced Cardiac Fibrosis

Androgen has anabolic effects on cardiac myocytes and has been shown to enhance left ventricular enlargement and function. However, the physiological and patho-physiological roles of androgen in cardiac growth and cardiac stress-induced remodeling remains unclear. We aimed to clarify whether the androgen-nuclear androgen receptor (AR) system contributes to the cardiac growth and angiotensin II (Ang II)-stimulated cardiac remodeling by using systemic AR-null male mice. AR knock-out (ARKO) male mice, at 25 weeks of age, and age-matched wild-type (WT) male mice were treated with or without Ang II stimulation (2.0 mg/kg/day) for 2 weeks. ARKO mice with or without Ang II stimulation showed a significant reduction in the heart-to-body weight ratio compared with those of WT mice. In addition, echocardiographic analysis demonstrated impairments of both the concentric hypertrophic response and left ventricular function in Ang II-stimulated ARKO mice. Western blot analysis of the myocardium revealed that activation of extracellular signal-regulated kinases (ERK) 1/2 and ERK5 by Ang II stimulation were lower in ARKO mice than those of WT mice. Ang II stimulation caused more prominent cardiac fibrosis in ARKO mice than in WT mice with enhanced expression of types I and III collagen and transforming growth factor-beta1 genes and with increased Smad2 activation. These results suggest that, in male mice, the androgen-AR system participates in normal cardiac growth and modulates cardiac adaptive hypertrophy and fibrosis during the process of cardiac remodeling under hypertrophic stress.

Effects of graded-release diltiazem versus ramipril, dosed at bedtime, on early morning blood pressure, heart rate, and the rate-pressure product

Background Therapeutic agents for the treatment of hypertension may differ in their efficacy during the early morning period, a time when both morbid and mortal cardiovascular events are increased compared to other times of the day. Methods We studied the effects of a graded-release delivery system of diltiazem (diltiazem HCL extended release tablets) versus ramipril, both dosed at bedtime, on blood pressure (BP), heart rate, and the heart rate-systolic BP product during the first 4 hours after awakening in a double-blind, titration-to-effect trial. There were 261 men and women enrolled in the trial with an untreated sitting diastolic BP of 90 to 109 mm Hg and ambulatory daytime diastolic BP of 85 to 109 mm Hg. Patients were randomized to either diltiazem extended release (ER) tablets each evening (240 mg titrated to 360 mg and to 540 mg) or ramipril each evening (5 mg titrated to 10 mg and to 20 mg). Early morning assessments of BP, heart rate, and the heart rate-systolic BP product were performed using 24-hour ambulatory recordings after 10 weeks of therapy. Results In each therapeutic group, 76% of patients were titrated to the highest possible dose. After 10 weeks of treatment, reductions in early morning BP by diltiazem ER tablets were significantly greater (−18/−15 mm Hg) than reductions by ramipril (−13/−8 mmHg , P < .005 for systolic BP and P < .001 for diastolic BP). Diltiazem ER tablets also led to greater reductions in morning heart rate and the heart rate-pressure product compared to ramipril. Reductions in mean 24-hour diastolic BP, heart rate, and the rate-pressure product were greater in patients treated with diltiazem ER tablets compared to ramipril, while reductions in 24-hour systolic BP were similar in each group. The observed adverse effects were not serious and incidences were similar for the 2 treatment groups. Conclusions These data demonstrate that bedtime administration of diltiazem ER, an agent designed to parallel the circadian rhythm of BP and heart rate, led to significantly greater early morning hemodynamic effects compared to the angiotensin-converting enzyme inhibitor ramipril, also dosed in the evening.

The effect of ventilation on spectral analysis of heart rate and blood pressure variability during exercise

Heart rate variability (HRV) and systolic blood pressure variability (BPV) during incremental exercise at 50, 75, and 100% of previously determined ventilatory threshold (VT) were compared to that of resting controlled breathing (CB) in 12 healthy subjects. CB was matched with exercise-associated respiratory rate, tidal volume, and end-tidal CO(2) for all stages of exercise. Power in the low frequency (LF, 0.04-0.15 Hz) and high frequency (HF, >0.15-0.4 Hz) for HRV and BPV were calculated, using time-frequency domain analysis, from beat-to-beat ECG and non-invasive radial artery blood pressure, respectively. During CB absolute and normalized power in the LF and HF of HRV and BPV were not significantly changed from baseline to maximal breathing. Conversely, during exercise HRV, LF and HF power significantly decreased from baseline to 100% VT while BPV, LF and HF power significantly increased for the same period. These findings suggest that the increases in ventilation associated with incremental exercise do not significantly affect spectral analysis of cardiovascular autonomic modulation in healthy subjects.

Exercise Reduces Myocardial Workload in Female Spontaneously Hypertensive Rats

1094 The pressure overload associated with chronic hypertension negatively impacts both myocardial structure and function. Myocardial workload is augmented to combat the increased afterload associated with chronic hypertension. The increased workload induces pathological, concentric hypertrophy, a condition in which mortality is doubled. PURPOSE: To examine how exercise training impacts myocardial workload in hypertension. Methods: Twenty-three, 16-week old female spontaneously hypertensive rats (SHR) were randomly placed into a low intensity treadmill exercise training group (EX, n = 12; 20 m/min, 1 hr/day, 5 d/wk for 12 weeks) or kept sedentary (n = 11). Systolic blood pressure (SBP) and heart rate (HR) were collected bi-weekly utilizing the tail-cuff occlusion method. Rate pressure product (RPP) was calculated utilizing the following equation; RPP = SBP * HR. M-mode imaging of the parasternal 2-D short axis view was used to obtain left ventricular anterior wall (AW) and posterior wall (PW) thickness during both systole and diastole along with left ventricular enddiastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD). Results: At 28-weeks of age, despite similar SBP values (SED; 178 ± 10.9 vs. EX; 175 ± 10.7 mmHg, p = 0.2) both HR (SED; 520 ± 17.7 vs. EX; 470 ± 45.8 bpm, p<0.05) and RPP (SED; 92935 ± 7709.6 vs. EX; 82282 ± 9924.5, p<0.05) were significantly lower in the EX group. In addition, despite similar heart weights (SED; 1.18 ± .14 vs. 1.25 ± .12 grams, p = 0.15) both end diastolic AW thickness (SED; 1.77 ± .13 vs. EX; 1.94 ± .13 mm, p<0.05) and PW thickness (SED; 1.63 ± .08 vs. EX; 1.85 ± .24 mm, p<0.05) were significantly greater in the EX group with similar patters existing during systole. LVEDD (SED; 6.33 ± .41 vs. EX; 6.17 ± .78 mm, p = 0.28) and LVESD (SED; 2.90 ± .69 vs. EX; 2.62 ± .75 mm, p = 0.18) were similar between SED and EX groups. Conclusion: Exercise training attenuated both HR and RPP. In addition, exercise training increased both AW and PW thickness at similar SBP and LVEDD, resulting in a diminished LV diastolic wall stress. These exercise induced physiologic adaptations may protect the myocardium from the deleterious remodeling pattern that occurs with chronic hypertension. Supported by: Research Incentive Fund, Temple University