Heart Rate Systolic Blood Pressure Research Articles

Effects of heart rate on phasic Y-graft blood flow and flow reserve in patients with complete arterial myocardial revascularizaton: an intravascular Doppler catheter study.

It is not well established whether the blood flow of arterial composite Y-grafts can efficiently respond to the flow demand of the coronary system early postoperatively. The aim of this study was to evaluate if soon after the operation, arterial composite Y-grafts can increase blood flow in response to an increase in myocardial oxygen consumption (MVO2). Twenty-seven patients who received complete arterial myocardial revascularization using the left internal thoracic artery (LITA) and the radial artery (RA) as composite Y-graft gave their consent to a pre-discharge coronary angiography and intravascular flow velocity measurements using a Doppler guide wire. Flow measurements were performed in the LITA main stem, the distal LITA and the RA, both at rest and during atrial pacing at the 85% of the patient age-predicted maximum. The heart rate-systolic blood pressure product was considered as an indirect index of MVO2. Hyperemic flow was determined after injection of adenosine. The flow reserve (FR) was defined as the ratio of blood flow during maximal hyperemia (Qmax) to baseline flow (Qbasal). Atrial pacing increased MVO2 significantly (P<0.000). None of the patients developed ischemic S-T segment modifications or complained of chest pain. Q(basal) increased significantly in the LITA main stem (P=0.001), distal LITA (P=0.041) and RA (P=0.004) while Qmax did not change significantly. As a consequence, the FR decreased in the LITA main stem (P=0.002), distal LITA (P<0.000) and RA (P<0.000) but was not completely exhausted. Soon after the operation, arterial composite Y-grafts can significantly increase blood flow in response to conditions of increased MVO2, keeping normal the myocardial O2 supply-to-demand ratio.

Preventing increases in early-morning blood pressure, heart rate, and the rate-pressure product with controlled onset extended release verapamil at bedtime versus enalapril, losartan, and placebo on arising

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 with other times of the day. Methods We studied the effects of a chronotherapeutic delivery system of verapamil (controlled-onset extended release [COER]-24 system) dosed at bedtime versus conventional morning administration of both enalapril and losartan on the blood pressure (BP), heart rate, and the heart rate systolic BP product during the first 4 hours after awakening in a placebo-controlled, forced-titration trial. There were 357 men and women enrolled in the trial with an untreated sitting diastolic BP of 95 to 114 mm Hg and ambulatory daytime diastolic BP ≥85 mm Hg. Patients were randomized to either COER-verapamil hydrochloride each evening (240 mg titrated to 360 mg), enalapril each morning (10 mg titrated to 20 mg), losartan each morning (50 mg titrated to 100 mg), or placebo. Early morning assessments of BP, heart rate, and the heart rate systolic BP product were performed by use of 24-hour ambulatory recordings after 4 weeks (low dose) and 8 weeks (high dose) of therapy. Results Results were similar at weeks 4 and 8 for all treatment groups except that the magnitude of change was greater at week 8. After 8 weeks of treatment, reductions in early morning BP by COER-verapamil were significantly greater (−15/−10 mm Hg) than enalapril (−9/−7 mm Hg, P <.01) and losartan (−8/−5 mm Hg, P <.001). COER-verapamil also led to greater reductions in morning heart rate, the rate-pressure product, and the rate-of-rise of BP compared with the other 2 active treatment groups. Reductions in mean 24-hour BP were greater in patients treated with COER-verapamil compared with placebo and losartan, and similar to reductions in patients treated with enalapril. Conclusions Bedtime administration of an agent designed to parallel the circadian rhythm of BP and heart rate led to significantly greater early morning hemodynamic effects compared with other conventional once-daily antihypertensive agents dosed in the morning. (Am Heart J 2002;144:657-65.)

Blood pressure and urinary cations in a low-fat intake Chinese population sample

Background — The relationship between cation intake and blood pressure (BP) in populations with specific dietary habits such as a low fat intake, remains unclear. A low fat intake has been prevalent during human evolution.Methods — The average of 6 BP readings and heart rate (HR) recordings has been calculated. Dietary intake was measured using the 24h recall-method. A 24h urine sample was collected.Results — A highly significant correlation was found between the sodium/potassium ratio (Na/K), after adjustment for age, weight, height, heart rate, alcohol intake and sex and systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse pressure (PP). The same applies to the sodium/creatinine (Na/Cr) and potassium/creatinine (K/Cr) ratios, with a positive correlation for Na/Cr and a negative one for K/Cr.The partial regression coefficient was in absolute value about 4-5 times greater for K/Cr than for Na/Cr. Age correlates highly significantly and independently with both SBP and DBP.Conclusion — If a Na/K ratio of 1 is considered optimal, by achieving that goal mean SBP could be reduced by about 6 mm Hg and mean DBP by 3 mm Hg in this normotensive population.

Myocardial perfusion imaging findings and the role of adenosine in the warm-up angina phenomenon

OBJECTIVESThis study examined the roles of myocardial perfusion and adenosine in warm-up angina.BACKGROUNDIn warm-up angina, neither the role of an adenosine-mediated mechanism, as is found in experimental ischemic preconditioning, nor of increased myocardial perfusion is well defined.METHODSIn substudy A, a single-photon emission computed tomography (SPECT)-thallium-201 exercise test was performed by 12 subjects with ischemic heart disease on three occasions one week apart. The third test was preceded by a warm-up test. The extent of the thallium deficit and its intensity on the third test were compared with the baseline tests controlling for the heart rate-systolic blood pressure product (RPP) at thallium injection. In substudy B, 12 similar subjects did two successive exercise tests at two separate sessions and received the adenosine antagonist, aminophylline (intravenous 5 mg/kg bolus and 0.9 mg/kg/h infusion) at one session, and equivalent saline at the other session. Change in ischemic threshold (RPP at 1 mm ST segment depression) and in maximum ST depression adjusted for RPP were analyzed.RESULTSIn substudy A, despite a significant attenuation of electrocardiogram indexes of myocardial ischemia between the baseline and third (warmed-up) tests, the thallium extent deficits (20.8 ± 15.1% and 16.8 ± 12.4%) and intensity deficits (41.2 ± 12.6% and 39.3 ± 12.6%) did not differ significantly. In substudy B, the increase in ischemic threshold on re-exercise was unaffected by aminophylline. Adjusted maximum ST depression even decreased to a greater extent on re-exercise with aminophylline (by 51 ± 21%) than with saline (by 32 ± 19%) (p = 0.012).CONCLUSIONSWhile warm-up angina is associated with a significant attenuation of exercise electrocardiogram indexes of ischemia, it is unaccompanied by significant changes in SPECT perfusion and does not appear to be mediated by an adenosine-dependent mechanism since it is not blocked by aminophylline. Thus, its mechanism, which appears distinct from experimental ischemic preconditioning, remains unidentified.

The influence of the alpha2-adrenoceptor agonist, clonidine, on the EEG and on the MAC of isoflurane

We investigated the influence of intravenous clonidine 2, 4 and 6 microg kg-1 on the electroencephalogram and on the minimal alveolar concentration of isoflurane in 40 patients aged 20-60 years undergoing elective surgery. Minimal alveolar concentration was determined using the Dixon 'up-and-down' method. Thirty min after the clonidine infusion anaesthesia was induced with etomidate, 0.25 mg kg-1. Skin incision was made after stable end-tidal isoflurane concentrations had been maintained for at least 15 min. Clonidine caused significant decreases in the spectral edge (95%) and median power frequency of the electroencephalogram and in the bispectral index. The minimal alveolar concentration of isoflurane decreased in a dose-dependent manner from 1.32% (95% CI, 1.28%-1.36%) in the control group to 1.03% (0.9%-1.18%) in patients given clonidine 6 microg kg-1. Clonidine 4 and 6 microg kg-1 was associated with a moderate reduction in heart rate and arterial systolic blood pressure. We recommend the use of clonidine intravenously as an adjunct to general anaesthesia in a dose of 4 microg kg-1 given 15 min before induction of anaesthesia.

Effects of the repeated administration of adenosine and heparin on myocardial perfusion in patients with chronic stable angina pectoris

The mechanism by which ischemia stimulates angiogenesis is unknown. Adenosine is released during myocardial ischemia and may be a mediator of this process. Experimental data suggest that heparin may enhance this effect. The purpose of this open-labeled, placebo-controlled trial was to determine whether repeated intravenous administration of adenosine and heparin could mimic physiologic angiogenesis and reduce the amount of exercise-induced myocardial ischemia in patients with coronary artery disease. Subjects with chronic stable angina refractory to conventional medical therapy and not suitable for revascularization received either adenosine (140 μg/kg/min for 6 minutes) and heparin (10,000 U bolus), (n = 14), or placebo, (n = 7) daily for 10 days. All patients underwent baseline and follow-up exercise testing with thallium-201 single-photon emission computed tomography myocardial perfusion imaging. A semiquantitative assessment of the extent and severity of the perfusion abnormalities was calculated by 2 blinded investigators. There was no significant change in exercise duration or in the peak heart rate systolic blood pressure product associated with adenosine and heparin compared with placebo treatment. There was, however, a 9% reduction in the extent (60.6 ± 4.0 vs 54.9 ± 4.1, p = 0.03) and a 14% improvement in severity (41.5 ± 3.2 vs 35.7 ± 2.9, p = 0.01) of the myocardial perfusion abnormalities seen in patients who received adenosine and heparin compared with placebo. Thus, in this pilot study, repeated administration of adenosine and heparin reduced the amount of exercise-induced ischemia in patients with chronic stable angina refractory to conventional treatment.

Vasodilator therapy of hypertensive acute left ventricular failure: Comparison of captopril-prazosin with Hydralazine-isosorbide dinitrate

A prospective study to evaluate and compare the cardiorespiratory effects and clinical efficacy of the Neurohormonal inhibitors (Captopril 50 mg+prazosin 1 mg only) and direct arteriolar and venular dilators (Intravenous hydralazine 30 mg+oral isosorbide dinitrate 30 mg) used as vasodilator therapy, was undertaken in a randomized, single blind study in 17 Nigerian patients with hypertensive acute left ventricular failure. Both vasodilator regimes separately and significantly reduced the systolic and diastolic blood pressures ( P<0.001 ANOVA), heart rate ( P<0.001 ANOVA), and the respiratory rate ( P<0.05 ANOVA), the double product, but increased the peak expiratory flow rate ( P<0.05 ANOVA). However, the neurohormonal antagonists, captopril and prazosin ( n=9) caused a statistically significantly greater reduction in heart rate ( P<0.05 ANOVA) respiratory rate ( P<0.05 ANOVA) and induced a significantly greater increase in the self-paced exercise capacity, 24 h after initiation of treatment, ( P<0.02) compared to the hydralazine and isosorbide dinitrate combination ( n=8). Five of the nine patients on the neurohormonal antagonist therapy were ambulant at 24 h, compared to none of the eight patients receiving conventional venular and arteriolar dilators hydralazine and isosorbide dinitrate ( X 2=5.84 dfi P<0.05). There was a significant inverse correlation between the systolic blood pressure heart rate product, and the distance covered during symptom limited self paced exercise capacity ( r=−0.58, P=0.0146 ANOVA). One of eight patients in the hydralazine+isosorbide nitrate combination died, but there was no mortality in the captopril+prazosin group. These findings collectively suggest that captopril+prazosin combination may be a superior vasodilator therapy compared to hydralazine-isosorbide dinitrate, in hypertensive acute pulmonary oedema.

Effects of buspirone on plasma neurotransmitters in healthy subjects.

Buspirone is an anxiolytic drug which exerts several central effects. It antagonizes presynaptic inhibitory DA2 autoreceptors at dopaminergic neurons and acts as an agonist for 5-HT1A inhibitor autoreceptors at serotonergic cells. Thus, buspirone respectively enhances and depresses the firing rates of both type of neurons. At doses which correlate with dopaminergic stimulation, but not 5-HT inhibition, buspirone also increases the firing rates of the central noradrenergic cells. We measured levels of circulating neurotransmitters before and up to 240 minutes after the oral administration of 20 mg of buspirone in 32 healthy volunteers. Buspirone significantly increased levels of noradrenaline, dopamine, and free serotonin but did not affect levels of adrenaline, tryptophane, or platelet serotonin. Small but significant drops in systolic blood pressure and heart rate were observed after buspirone ingestion. Atropine administration before buspirone ingestion annulled the free serotonin increase as well as systolic blood pressure-heart rate decrease. We found significant positive correlations between noradrenaline and dopamine levels. The strength and significance of these correlations were increased by using the noradrenaline/adrenaline ratio instead of noradrenaline absolute values. This finding indicates that increases in both noradrenaline and dopamine arise from sympathetic nerves rather than the adrenal glands. We also found significant negative correlations between free serotonin increases and systolic blood pressure-heart rate decreases. Our results indicate that buspirone stimulates central sympathetic activity. These acute effects of buspirone are reflected in an increased peripheral neural sympathetic activity, but not adrenal sympathetic activity in healthy individuals. In addition, buspirone increases free serotonin plasma concentrations and decreases systolic blood pressure plus heart rate levels through mechanisms associated with parasympathetic activation.

Pulmonary Infiltrates in Neutropenic Patients With Acute Leukemia During Chemotherapy: Outcome and Prognostic Factors

To determine predictors of mortality from pulmonary infiltrates in neutropenic patients with acute leukemia during chemotherapy, and the significance of those factors related to the underlying malignancy and its therapy as well as of those related to the severity of the illness associated with pulmonary infiltrates. A historical cohort study. A university teaching hospital and tertiary referral center. Overall, 53 patients with neutropenia during chemotherapy and with first episodes of pulmonary infiltrates during a 4-year period were studied. Prognostic analysis included 38 variables. Multivariate analyses were performed by logistic regression. The survival rate from pneumonia was 57% (30/53). The following eight parameters were significantly associated with death in univariate analysis: comorbidity present; development of "late" pulmonary infiltrates (> or = 14 days after hospital admission); heart rate > or = 100 beats/min; a ratio heart rate/systolic blood pressure (HR/SBP) > or = 1.2; urea nitrogen > 7 mmol/L; radiographic score > or = 3; neutropenia < 1.0x10(9)/L at the treatment end point; and failed complete remission. In a multivariate model including only parameters available at diagnosis of pulmonary infiltrates, the presence of a ratio HR/SBP > or = 1.2 and of a radiographic score > or = 3 remained independently associated with death. In a second model also including the evolutionary parameter neutropenia < or = 1.0x10(9)/L at the treatment end point, both parameters remained significant together with neutropenia <1.0x 10(9)/L at the treatment end point. The presence of a ratio HR/SBP > or = 1.2 was a strong marker of early death. Both therapy- and malignancy-associated neutropenia as well as the severity of illness associated with pulmonary infiltrates are independent prognostic factors. Patients with a ratio HR/SBP > or = 1.2 at diagnosis of pulmonary infiltrates suffer from potentially reversible acute illness, are at risk for early death and, therefore, may be appropriate candidates for treatment in an ICU.

Relationship between Hyperinsulinemia and Ambulatory Blood Pressure Monitoring of Lean and Overweight Male Hypertensives

To elucidate the role of hypertension as part of a state of insulin resistance. Thirty-one uncomplicated hypertensive men not receiving antihypertensive treatment or who had been without treatment for a 4-week washout period and 10 lean normotensive controls were compared. Hypertensive men were divided according to their body mass index into three groups. All subjects came to the clinic for measurements of height, weight, hip and waist circumferences, and sitting blood pressure, and to begin 24 h ambulatory blood pressure monitoring. Plasma glucose and insulin levels were measured during a 2 h oral glucose (75 g)-tolerance test. For the hypertensive population as a whole, behaviors of studied variables among dippers (n = 18) and nondippers (n = 13) were determined. During oral glucose-tolerance testing blood glucose levels after 60 min and 120 min were significantly higher (P < 0.05) in members of the high body mass index group than they were in members of the low body mass index group. Insulin levels of members of the high and middle body mass index groups were higher than those of members of the low body mass index group after 60 min (P < 0.05 for both comparisons) and 120 min (P < 0.05 for both comparisons). The mean serum insulin level in members of the low body mass index group was significantly higher than that in normotensives after 30 min, 60 min and 120 min (P < 0.05 for all three comparisons). The mean serum insulin: plasma glucose ratio for men in the low BMI group was significantly higher than that for normotensives after 60 min and 120 min (P < 0.05 for both comparisons). Correlations of blood pressure and insulin levels were not significant. Levels of high-density lipoprotein cholesterol and triglycerides were lower in members of the group with high body mass index than they were in members of the group with low body mass index. Total cholesterol: high-density lipoprotein cholesterol ratio was higher for members of the high body mass index group than it was for members of the middle body mass index group. Weight, body mass index, casual systolic blood pressure, 24 h average systolic blood pressure and diastolic blood pressure, 0700-2300 h systolic blood pressure, and 24 h average heart rate-systolic blood pressure product of dippers were significantly lower than those of nondippers. These results suggest that hypertension and being overweight have additive effects increasing insulinemia and that being overweight is associated with a significantly lower nocturnal fall in blood pressure.

Anger Expression and Cardiovascular Reactivity to Mental Stress: A Spectral Analysis Approach

The cardiovascular reactivation to a recently described videogame task i.e. a maze test was evaluated in the time and frequency-domain using finger blood pressure (BP) measurement in 25 subjects on no medication, including 6 subjects with mild hypertension. Prior to BP measures subjects completed the items of the State-Trait Anger Expression Inventory questionnaire corresponding to the trait anger and anger expression scales. The BP recording session was divided into resting, test and recovery periods. A detrending procedure was applied to each recording prior to the fast Fourier transform. Systolic BP (SBP) and heart rate (HR) were increased during the test. The mid-frequency (MF,0.1 Hz) components of SBP and HR variability were also elevated during the stressful period. In resting conditions SBP levels of subjects with low trait anger was lower than in subjects with high trait anger (128i4 mmHg, n=14 versus 148i4 mmHg, n =l l, Pc0.01, Student t test). Nevertheless the average SBP increase due to the stress was of similar magnitude in these two subgroups(14 mmHg). A significant negative relationship was observed between anger-out expression score and the MF SBP variation(r=-0.46, PcO.05). A significant negative relation was found between anger-in mode of expression and the HR peak during the test(r=-0.43, PcO.05). In conclusion, our data suggest that individuals who are often in anger-provoking situations (high trait anger) should have heightened BP.Two different patterns of cardiovascular responses (SBP variability and HR levels) were observed for the outward and inward mode of expression of anger. This may reflect a different psychological control of HR levels and BP variability.

Cardiac Ischemia During Weaning From Mechanical Ventilation

In this prospective study, we measured the ST segments, heart rate-systolic BP product (RPP), respiratory rate to tidal volume ratio (RVR), and pulse oximetry saturations of patients in our medical/cardiac ICUs before and during weaning from mechanical ventilation. Ninety-three patients were enrolled with a mean age of 66.5 +/- 15.0 years (mean +/- SD), mean acute physiology and chronic health evaluation (APACHE) II score of 16.0 +/- 6.9, and mean duration of mechanical ventilation of 5.2 +/- 8.6 days. Forty-nine patients had coronary artery disease (CAD). Six of 93 patients (6.4%) experienced ECG evidence of ischemia during weaning. Five of these six had a precedent history of CAD and four failed initial weaning attempts (22% of patients with CAD who failed weaning). The RPP, for the group as a whole, increased significantly during weaning from 12.0 +/- 3.1 to 13.4 +/- 4.0 mm Hg.bpm.10(3) (p<0.01). The rate to volume ratio did not change significantly during weaning, except in the subgroup of patients who failed to wean, in whom it increased from 98.4 +/- 45.2 to 124.9 +/- 54.9 bpm/L (p<0.05). Oxygenation also decreased significantly from 0.98 +/- 0.02 to 0.96 +/- 0.03 and was significantly associated with weaning failure (risk ratio [RR]=3.9; 95% confidence interval [CI]=1.7 to 9.0). Thirty-seven patients failed the initial weaning attempt. Cardiac ischemia (RR= 1.8; 95% CI=1.0 to 3.4) and an increased RVR (RR=1.7; 95% CI=0.9 to 3.4) tended to increase the risk of weaning failure. Cardiac ischemia, although infrequent (6%) in the general population of weaning medical/cardiac ICU patients, should be considered in patients with CAD who fail to wean.

Maximal exercise hemodynamics and risk of mortality in apparently healthy men and women.

The purpose of this investigation was to determine the association of maximal exercise hemodynamic responses with risk of mortality due to all-causes, cardiovascular disease (CVD), and coronary heart disease (CHD) in a population of apparently healthy individuals. Study participants were 20,387 men (mean age = 42.2 yr) and 6,234 women (mean age = 41.9 yr), patients of a preventive medicine center in Dallas, TX, examined between 1971 and 1989. Maximal heart rate and maximal systolic blood pressure (SBP) measured during the maximal exercise test were related to risk of all-cause, CVD, and CHD mortality. During an average of 8.1 yr of follow-up, there were 348 deaths in men and 66 deaths in women. Among men, after adjustment for confounding variables, risks (and 95 percent confidence interval (CI)) of all-cause mortality for quartiles of maximal SBP, relative to the lowest quartile, were: 0.96 (0.70-1.33), 1.36 (1.01-1.85), and 1.37 (0.98-1.92) for quartiles 2-4, respectively. Similarly adjusted risks for maximal heart rate were: 0.61(0.44-0.85), 0.69 (0.51-0.93), and 0.60 (0.41-0.87). Similar results were seen for risk of CVD and CHD death. In women, similar trends in adjusted risks of all-cause and CVD mortality across maximal SBP and heart rate categories were observed. For maximal heart rate, a 35 bpm higher value was associated with a 36 percent decreased risk of CVD mortality in men (RR = 0.63,95 percent CI = 0.34-0.71) and an 8 percent lower risk in women (RR = 0.92,95 percent CI = 0.18-4.63). These results suggest that an exaggerated SBP or an attenuated heart rate response to maximal exercise may indicate an elevated risk for mortality in this apparently healthy population.

Resuscitation of the critically III in the ED: Responses of blood pressure, heart rate, shock index, central venous oxygen saturation, and lactate

To describe the simultaneous responses of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), heart rate (HR), shock index ( SI = HR SBP ), central venous oxyhemoglobin saturation (ScvO 2), and arterial blood lactate concentration (Lact) to resuscitation of critically ill patients in the emergency department (ED), an observational descriptive study was conducted in the ED of an urban teaching hospital. Thirty-six patients admitted from the ED to the medical intensive care unit were studied. Vital signs were measured immediately on arrival to the ED (phase 1). After initial resuscitation and stabilization, ie, HR between 50 and 120 beats/min and MAP between 70 and 110 mm Hg (phase 2), ScvO 2 and Lact were measured and additional therapy was given in the ED to increase ScvO 2 to >65% and decrease Lact to <2 mmol/L, if needed (phase 3). SBP, DBP, MAP, HR, SI, ScvO 2, and Lact were measured. Initial resuscitation increased SBP from 103 ± 39 to 118 ± 29 mm Hg ( P < .05) and MAP from 67 ± 35 to 82 ± 22 mm Hg ( P < .05) but did not affect DBP (53 ± 35 to 63 ± 22 mm Hg, P = NS), HR (110 ± 26 to 110 ± 22 beats/min, P = NS) or SI (from 1.3 ± 0.7 to 1.0 ± 0.3, P = NS) from phase 1 to phase 2. ScvO 2 remained <65% and/or Lact >2.0 mmol/L in 31 of 36 patients at phase 2, and additional therapy was required. Lact was decreased (from 4.6 ± 3.8 to 2.6 ± 2.5 mmol/L, P < .05) and ScvO 2 was increased (from 52 ± 18 to 65 ± 13%, P < .05) without significant additional changes in SBP, DBP, MAP, HR, or SI at phase 3. The in-hospital mortality was 14% for this group of patients. It was concluded that additional therapy is required in the majority of critically ill patients to restore adequate systemic oxygenation after initial resuscitation and hemodynamic stabilization in the ED. Additional therapy to increase ScvO 2 and decrease Lact may not produce substantial responses in SBP, DBP, MAP, HR, and SI. The measurement of ScvO 2 and Lact can be utilized to guide this phase of additional therapy in the ED.

Impact of echocardiographic left ventricular mass on mechanistic implications of exercise testing parameters

Electrocardiographic left ventricular (LV) hypertrophy has long been known to be associated with an abnormal ST-segment response to exercise; this association has been considered to represent a false-positive finding. There is a paucity of data relating echocardiographic LV mass to exercise ST-segment responses and other exercise parameters. As part of a routine evaluation, 1,408 men and 1,618 women from the Framingham Heart Study who were free of clinical cardiac disease underwent echocardiography and exercise treadmill testing according to the Bruce protocol at the same clinic visit. Abnormal ST-segment responses were defined both by standard criteria and the ΔT/heart rate index. LV mass was calculated from M-mode echocardiography. Echocardiographic LV hypertrophy was associated with an abnormal ΔST/heart rate index (in men, odds ratio [OR] 1.78, 95% confidence interval [CI] 1.05 to 3.01, p = 0.03; in women, OR 2.13, 95% CI 1.31 to 3.44, p = 0.002) but not with an abnormal response according to standard criteria. Echocardiographic LV hypertrophy was also associated with a lower likelihood of achieving an age-predicted target heart rate (in men, OR 0.45, 95% CI 0.31 to 0.65, p < 0.001; in women, OR 0.53, 95% CI 0.37 to 0.76, p < 0.001) and with a lower exercise capacity. Despite these associations, echocardiographic LV hypertrophy was associated with a higher peak heart rate-systolic blood pressure double product. In conclusion, echocardiographic LV hypertrophy is associated with an abnormal ST-segment response, a lower likelihood of achieving target heart rate, decreased exercise capacity, and an increased double product, which is a reflection of myocardial oxygen demand.

Combined arm exercise and dipyridamole stress thallium imaging for the detection of coronary artery disease

The safety and usefulness of combined isotonic-isometric arm exercise along with dipyridamolethallium 201 imaging for the detection of coronary artery disease (CAD) was tested in 50 patients. Dipyridamole (0.5 mg/kg) was injected i.v. for 4 minutes, followed by a 4-minute exercise of both arms. Fifty matched patients receiving dipyridamole only were imaged for comparison. Peak heart rate (mean 118 vs 77 b/minutes) and peak systolic and diastolic blood pressure were significantly higher in the exercised group. Evidence of myocardial ischemia, ST depression (82% vs 60%), Th-201 redistribution (85% vs 68%), and the target-to-background counts ratio were also more profound in this group, though side effects were fewer. It is concluded that arm exercise combined with dipyridamole-thallium imaging is safe and provides more reliable results in assessing CAD than dipyridamole alone followed by Th-201 imaging. It is therefore recommended for patients who are unable to perform lower limb exercise.

807-2 Effect of Age on Left Ventricular Diastolic Filling Patterns During Orthostatic Stress

Although numerous studies have demonstrated reduced early diastolic left ventricular (LV) peak filling velocity IE) and accentuated late filling velocity (A) with advancing age in the supine position, the effect of orthostatic stress on age-associated diastolic filling patterns is unknown. Accordingly, 30 healthy normotensive volunteers ages 19 to 90 years from the Baltimore Longitudinal Study of Aging underwent sequential Doppler echocardiography after 3 minutes each in the supine, seated, and standing positions. In the overall sample, standing was accompanied by an increase in heart rate (HR) of 8.8 ± 1.7 beats/min, and decreases in E(20.6 ± 2.7 cm/sl. A 150 ± 2.7 cm/s)and LV diastolic dimension (LVDD) (7.8 ± 0.8 mm), x ± SEM, each p &lt; 0.001 versus supine values. Systolic blood pressure (SBP) and atrial filling fraction (AFF) were unaffected by posture. Correlation coefficients versus age for relevant Doppler and hemodynamic variables are shown. E A E/A AFF HR SBP LVDD Supine -0.58 † 0.80 † -0.78 † 0.84 † 0.01 0.56 † -0.14 Sit -0.36 0.77 † -0.83 † 0.78 † -0.04 0.37 * -0.07 Stand -0.24 0.60 † -0.69 † 0.71 † -0.32 0.47 † 0.09 ΔSupine → Stand 0.53 † -0.46 † 0.56 † -0.17 -0.61 † 0.22 0.40 * * p &lt; 005 † p &lt; 001 Thus, orthostatic stress abolishes the reduction of E and attenuates the exaggerated A observed with advancing age in the supine position. probably because of the blunted standing-induced HR increase in older subjects. However, the supine age-associated increase in AFF is unaffected by orthostasis.

Acupuncture in angina pectoris: do psycho-social and neurophysiological factors relate to the effect?

We studied the effect of acupuncture in 49 patients with angina pectoris with focus on its relationship to psycho-social factors and changes in skin temperature, pain thresholds, and pain tolerance thresholds. No significant influence from patient expectation, social stress (strain) or profiles of the Minnesota Multiphasic Personality Inventory (MMPI) was found (all p > 0.1). Acupuncture slightly increased exercise tolerance (median 7%), the difference in Systolic Blood Pressure-Heart Rate Product between rest and maximal exercise (delta PRP) (median 3%), and the time to onset of pain (median 10%); decreased nitroglycerin consumption (median 58%) and anginal attack rate (median 38%). Improvement in exercise tolerance was significantly correlated to an improvement in delta PRP (correlation coefficient = 0.7; p < 0.0001) but not to time of myocardial ischemia (correlation coefficient = 0.1; p = 0.1). Compared with 28 patients with a less pronounced anti-anginal effect, the 21 patients with a pronounced effect had a significant increase in local skin temperature, but had no significant change in distant skin temperature and pain thresholds. It is concluded that acupuncture, due to hemodynamic alterations, might have a specific effect on angina pectoris in addition to drug treatments.

Effects of intravenous theophylline on exercise-induced myocardial ischemia: II. A concentration-dependent phenomenon

Objectives. The effects of varying concentrations of theophylline on exercise-induced myocardial ischemia were evaluated in patients with stable coronary artery disease.Background. Theophylline is a competitive antagonist of adenosine and may have potential as an anti-ischemic medication. It is not known whether these effects on myocardial ischemia are concentration dependent.Methods. In a double-blind, randomized, crossover manner, 11 patients received, at 1-week intervals, placebo and each of three theophylline doses by intravenous infusion for 45 min. Graded exercise testing was performed before randomization and immediately after each infusion. Concurrent anti-ischemic medications were withheld for 24 h before each exercise test. Serum theophylline concentrations achieved were 3.9 ± 1.0 mg/liter (low), 8.2 ± 1.8 mg/liter (medium) and 13.2 ± 2.3 mg/liter (high).Results. Compared with placebo, none of the three theophylline infusions produced a significant alteration in rest heart rate, blood pressure, mean frequency or severity of ventricular ectopic activity or noncardiac symptoms. The time to onset of ischemia was progressively increased, with medium and high concentrations achieving statistical significance. Similar patterns were observed for oxygen uptake and the heart rate-systolic blood pressure product at the onset of ischemia. Total exercise duration was significantly prolonged with the medium and high concentrations.Conclusions. It is concluded that administration of varying doses of theophylline before exercise produces a clinically significant and concentration-dependent improvement in the indicators of myocardial ischemia in patients with chronic stable coronary artery disease.

Effect of dipyridamole therapy on myocardial ischemia in patients with stable angina pectoris receiving concurrent anti-ischemic therapy

The effects of oral dipyridamole on exercise performance and anginal symptoms were evaluated in 15 men with stable angina pectoris. In a double-blind, randomized, crossover design, patients received 75 mg of dipyridamole or placebo every 8 hours for 2 weeks in addition to their previously prescribed cardiac medications. Graded exercise tolerance testing was performed twice before randomization, at the end of each treatment period, and after single-blind placebo washout. When compared with baseline tests, the time to onset of 0.1 mV ST-segment depression was similar between dipyridamole and placebo treatments (316 ± 89 vs 345 ± 102 seconds, respectively, p = not significant). No significant differences existed between treatments in the peak systolic blood pressure-heart rate product or in the duration of exercise. Angina pectoris occurred during all 3 baseline exercise tests in 7 of the 15 subjects; the time to onset of angina was unchanged by either treatment. Analysis of symptom diaries conducted in 13 patients revealed no significant alteration in reported anginal symptoms during dipyridamole treatment compared with placebo treatment (0.6 ± 0.9 vs 0.3 ± 0.4 episodes per week). Ambulatory electrocardiographic monitoring in 12 patients revealed few episodes of ischemia during daily activities with no alteration in frequency of episodes during treatment periods. Plasma concentrations of dipyridamole did not correspond with the outcomes of exercise testing. It is concluded that chronic oral dipyridamole therapy given in its usual clinical dose does not adversely affect exercise performance, daily anginal episodes or ambulatory ischemia in patients receiving concurrent antiischemic medication.