Differences In Rate-pressure Product Research Articles

The effects of rate pressure product at admission on cardiopulmonary function during hospitalization in patients with acute myocardial infarction

ABSTRACT Objective This study aimed to analyze the correlation between the rate pressure product (RPP) and cardiopulmonary function during hospitalization in patients with acute myocardial infarction (AMI). Methods A total of 362 patients with AMI were selected for the study, and the median admission RPP was used as the cutoff point to divide the patients into a low-RPP group (n = 181) and a high-RPP group (n = 181). The relationship between the RPP at admission and the cardiopulmonary function during hospitalization was analyzed. Results The patients in the high-RPP group had a higher body mass index (BMI) (p = 0.014), a higher prevalence of combined hypertension and diabetes mellitus (p < 0.001), a lower incidence of smoking (p = 0.044), and a higher incidence of oscillatory ventilation (6.1% vs. 1.7%, p = 0.029). The differences in RPP at rest, during warm-up, and within 1 and 4 minutes of recovery were statistically significant between the two groups (p < 0.01 on each occasion), while the differences in anaerobic threshold (AT) and watt max (Max) were not statistically significant (p > 0.05 for both). The patients in the low-RPP group had higher oxygen uptake (VO2 [AT]: 14.9 ± 3.4 vs. 14.2 ± 3.6, p = 0.048) and (VO2peak [Max]:18.2 ± 3.8 vs. 17.3 ± 3.8, p = 0.020). The RPP at admission was negatively correlated with VO2 (AT) and VO2peak (p < 0.05) using the regression Equation VO2peak = 33.682 + (−0.012 * RPP at admission/100) + (−0.105 * Age) + (−0.350 * BMI), while there was no correlation between the RPP at admission and VO2 (AT) (p = 0.149). Conclusion The RPP at admission was negatively correlated with cardiopulmonary function during hospitalization in patients with AMI. Patients with a high RPP were more likely to have a combination of obesity, hypertension, diabetes mellitus, and reduced oxygen uptake during exercise, while a high RPP at admission appeared to affect their cardiovascular response indicators during exercise.

Rate pressure product and its association with body mass index and blood groups in young adults

Background: Increased body mass index (BMI) and adiposity are considered a major health hazards. Overweight and obesity are associated with numerous diseases. Obesity independently can lead to the development of various health problems or can potentiate health problems in association with other risk factors. According to the scientific data available, people of different blood groups of the ABO system are susceptible to certain specific diseases. Rate pressure product (RPP) is one of the valuable markers of cardiac function. Increased RPP, an index of myocardial work stress, is an indicator of cardiovascular risk. Aim and Objective: The present study is taken up to find out the association between RPP, BMI, and ABO blood groups. Materials and Methods: A total of 143 subjects participated in the study. BMI was calculated using Quetelet’s index and categorized based on consensus for Asian population. Blood grouping was done by slide agglutination technique and subjects were grouped into A, B, AB, and O blood groups. RPP was calculated as product of systolic blood pressure and heart rate. Data collected were analyzed using suitable statistical tests. Results: There is a statistically significant difference in RPP of males and females, with males having a higher RPP (P = 0.037) and statistically significant association between gender and RPP (P = 0.044); 60% of males had a raised RPP. There is no statistically significant difference in RPP across BMI categories (P = 0.939) and no statistically significant association between BMI and RPP (P = 0.512). Although not statistically significant, RPP was higher in AB blood group in males and was lower in O blood group in females. There was no statistically significant correlation between blood groups and RPP in both male and female young adults. Conclusions: Males have higher RPP. There is no difference in RPP across BMI categories and no significant association between BMI and RPP. There is no association between blood groups and RPP in young adults.

Cardiorespiratory Fitness and Its Relationship with Health Risk Factors Among University Students: A Comparison Between Iran and Italy

Background: Cardiorespiratory Fitness (CRF) and its associated modifiable and non-modifiable health risk factors are very important in clinical studies. Objectives: This study aimed to compare health risk factors affecting CRF between Iranian and Italian male and female exercise science students. The correlation between VO2max and these factors was also evaluated. Methods: The sample consisted of 87 sport science students from the University of Milan (25 males and 17 females) and the University of Mazandaran (20 males and 25 females) aged 23.69 ± 1.95 years. The level of Physical Activity (PA) and body composition indices were obtained as health risk factors. Then, CRF was assessed by the Bruce test. Rate Pressure Product (RPP), blood pressure, and Heart Rate (HR) were measured before, in the end, and six minutes after the end of the test. Results: Statistical analyses revealed significant differences in RPP, Systolic Blood Pressure (SBP) during exercise, resting SBP, and Waist-to-Height Ratio (WHtR) between Iranian and Italian males and significant differences in Waist-to-Hip Ratio (WHR) and body fat percentage between Iranian and Italian females (P &lt; 0.05). The relationships between VO2max and resting RPP, resting HR, heart rate recovery, step counts, and vigorous PA were significant in all groups (P &lt; 0.05). Conclusions: As an assessment of VO2max, CRF is associated with hemodynamics and health risk factors. Age, sex, ethnicity, lifestyle, and culture of people in different geographical regions can affect health risk factors.

A study on rate pressure product in south Indian pregnant women with anaemia

Background: Anaemia is a cause of serious concern and contributes to a significantly higher maternal mortality. Rate Pressure Product (RPP) is a major determinant of myocardial oxygen consumption and blood flow. There is an increase in oxygen demand in anemia. Thus, in the present study, we have compared the difference in RPP between a normal pregnant women and pregnant women with anemia.Methods: A total of 180 pregnant women (normal pregnant woman - 90 and pregnant woman with anaemia - 90) belonging to different trimesters of pregnancy were included in the study. Age, height, and weight were recorded, and their body mass index was calculated. The systolic blood pressure, diastolic blood pressure, heart rate was recorded and RPP was calculated.Results: There was a significant increase in RPP in pregnant woman with anaemia in all three trimesters of pregnancy, but the significant increase was more in the third trimester.Conclusions: The present study shows that there is an increase in RPP in pregnant woman with anaemia and they are more prone to hemodynamic stress and cardiovascular risks, especially in their third trimester of pregnancy. This hemodynamic change may be taken into account to prevent the cardiovascular complications associated with anemia in pregnancy. Thus, RPP can be used as a sensitive non-invasive simple marker for early diagnosis of cardiovascular disease in pregnant woman.

Abstract 17321: Race Differences in Hemodynamic Responses to Acute Mental Stress and the Role of Depressive Symptoms

Introduction: Increased hemodynamic responses to psychological stress have been associated with adverse CAD events. African Americans (AA) have worse CAD outcomes than other groups. Heightened hemodynamic responses to stress may play a role. Our hypothesis was that AA would have higher hemodynamic reactivity to a standardized mental stress compared to Non-African Americans (NAA). Methods: We evaluated 574 patients (163 AA) with CAD, who underwent a standardized mental stress challenge. Hemodynamics were obtained at rest, during stress (speaking task), and during recovery. The rate-pressure product (RPP) was calculated as systolic blood pressure (SBP) x heart rate (HR). Hemodynamic reactivity was evaluated as the difference in RPP at rest and during stress. Depressive symptoms were measured with the Beck Depression Inventory-II (BDI). Results: As compared to NAA, AA patients were younger, had lower education and income, and higher prevalence of diabetes, obesity, hypertension, smoking, and depressive symptoms (BDI mean scores 9.8 vs. 7.6, p= 0.003). AA patients had higher blood pressure during all three periods (Table). However, hemodynamic reactivity with stress was significantly lower in AA than NAA (RPP reactivity 3114 vs 3620, p= 0.02). Adjusting for baseline RPP, age, gender and smoking did not substantially alter the association. However, after adjusting for depressive symptoms, the association was attenuated by 23% (p=0.16). BMI, diabetes and beta-blocker use had minimal additional explanatory role. In the final model, baseline RPP, depressive symptoms and BMI were significantly associated with a lower RPP reactivity (p&lt;0.01). Conclusion: AA patients with CAD, compared with NAA, have elevated blood pressure throughout mental stress, but tend to have blunted hemodynamic reactivity to stress. Depressive symptoms, which are more elevated among AA, play a role in this different response to stress and may be implicated in the higher CAD risk of this group.

RE-EVALUATION OF TWO-DIMENSIONAL STRAIN IN THE PATIENTS WITH TYPE 2 DIABETES MELLITUS

ObjectivesBased on the ventricular-arterial coupling, the longitudinal strain (LS) of myocardium in the patients with type 2 diabetes mellitus (DM) were discussed in detail.MethodsEighty patients with DM were divided into...

AGING AND GENDER EFFECTS ON RATE-PRESSURE PRODUCT: AN INDEX OF MYOCARDIAL OXYGEN CONSUMPTION

Objectives: There are aging associated alterations in cardiac structure, metabolism, function. Evidence suggests alterations in myocardial metabolism contribute to the development, progression of heart failure. Hence it is essential to be aware of the impact of healthy aging on myocardial oxygen consumption. Rate-Pressure Product (RPP) is simple, non-invasive, easily measurable index of MVO2. Seeking the effect of aging, we measured RPP, in apparently healthy men and women of different age groups. To know the influence of gender we compared the RPP in men and women in each age group. Methods : A total 152 healthy subjects (91 men, 61 women) were classified by age into four groups. Studies included recording of anthropometric parameters, physiological parameters, brachial systolic and diastolic blood pressure and ECG. Rate-Pressure Product was calculated. Results: Subjects of both genders showed an age related (18-65 years) decline of resting heart rate. Healthy men showed a gradual decline of rate pressure product from 18-65 years. Healthy young women between 20-35 years showed higher rate pressure product compared to men. Below 20 years RPP was lower in women compared to men. Between 35-54 years the gender differences in RPP diminished. Beyond 55 years RPP was higher in women compared to men. Conclusion : Varying influence of aging on myocardial oxygen consumption observed in men and women. Healthy aging is associated with decline in myocardial oxygen consumption in men. In women no significant variation observed. In each age group gender differences in myocardial oxygen consumption observed.

Respostas cardiovasculares ao exercício resistido são afetadas pela carga e intervalos entre séries

the control of cardiovascular responses during resistance exercise (RE) is important for patient safety. to investigate the influence of repetition maximum (RM) and rest interval between sets (RI) on heart rate (HR), systolic blood pressure (SBP) and rate-pressure product (RPP) during RE. twenty healthy subjects (26 ± 5 years of age) underwent RE protocols involving three sets of leg press (6 and 12 RM) and RI proportional to the contraction time (1:3 and 1:5). The HR was checked on a continuous basis by using a cardiotachometer and the SBP was checked at the end of the sets, via a protocol validated by the auscultatory method. the HR was influenced by the workload (p = 0.008) and sets (p < 0.001), but not by the RI (p = 0.087). The SBP suffered from the isolated effect of the number of sets (p < 0.001) and RI (p = 0.017), but not from the workload (p = 0.95). The RPP rose in direct proportion to the workload (p = 0.036) and sets (p < 0.001), but in inverse proportion to the RI (p = 0.006). In 6 RM protocols, the variation in the HR was higher for RI = 1:3 (Δ = 11.2 ± 1.1 bpm) than for RI = 1:5 (Δ = 4.5 ± 0.2 bpm; p = 0.002), but there was no difference for 12 RM (Δ 1:3 = 21.1 ± 2.2 bpm; Δ 1:5 = 18.9 ± 2.0 bpm, p = 0.83). The RI influenced the variation in SBP in all loads (6 RM - Δ 1:3 = 10.6 ± 0.9 mmHg, Δ 1:5 = 6.6 ± 0.7 mmHg; p = 0.02 and 12 RM - Δ 1:3 = 15.2 ± 1.1 mmHg, Δ 1:5 = 8.4 ± 0.7 mmHg; p = 0.04). The RPP rose in proportion to the workload (p = 0.036) and to the sets (p < 0.001), but in inverse proportion to the RI (p = 0.006). With RI = 1:3, there was difference in RPP for 6 RM (Δ = 2,892 ± 189 mmHg.bpm) and 12 RM (Δ = 4,587 ± 300 mmHg.bpm; p = 0.018), but not with RI = 1:5 (6 RM: Δ = 1,224 ± 141 mmHg.bpm, 12 RM: Δ = 2,332 ± 194 mmHg.bpm; p = 0.58). regardless of the workload, an increased RI was associated with lower cardiovascular responses during RE, especially of SBP.

A TEN MINUTES RESTING INTERVAL AFTER SMOKING SHOULD BE TAKEN FOR SAFTY EXERCISE PRESCRIPTION

We aimed to investigate the acute effects of cigarette smoking on cardiovascular systems during exhaustive exercise, comparing different time conditions of smoking exposure. Study subjects consisted of 3 male and 2 female habitual smokers (S; 25.0±3.4 yrs), and 2 male and 3 female non-smokers (NS; 22.7±1.8 yrs). All the participants performed symptom-limited maximal graded exercise on a cycle ergometer under three various conditions; non-smoking(control),5 min. after(S5) and 10 min.after(S10) smoking a cigarette. Heart rate(HR) and blood pressure(BP) were recorded every one-minute before, through, and after exercise. Rate pressure product(RPP), which is often used a parameter of myocardial oxygen uptake, was also calculated using obtained HR and systolic blood pressure(SBP). As to acute responses of HR or BP, both S and NS did not show significant differences among control, S5 and S10 with each other. In NS, however. ANOVA demonstrated significant differences in RPP after 8min.pedaling, the RPP of S5(27,900±4,174bpm.mmHg) was higher than those of control(24,028±3,952bpm. mmHg, p < 0.05) and of S10(24,532±2,627bpm. mmHg, p < 0.05) respectively. This intensity of emiently increased RPP appearance was equaled to 10.7±1.7METs, that is, also just above the anaerobic threshold(AT) levels in all the subjects. It is accepted that the cardiovascular risks derived from exercise stress tends to be higher over the AT point, where sympathetic tone just begin to be alerted. This finding observed in NS is thought to be due to combined effects of not only exercise but smoking only one cigarette. It also suggests that even in habitual smokers who are accustomed to the exposure of nicotine and carbon monoxide, higher demanded exercise immediately after smoking lager amount of cigarettes would be considered strenuous to cardiovascular systems. From the viewpoint of preventive cardiology, we insist on being keen to RPP response above the AT level intensity. In conclusion, at least 10 minutes resting interval after smoking should be taken for the safety exercise prescription.

Cardiovascular Response During ECT: A Cross-Over Study Across Stimulus Conditions

This study examined the effect of stimulus conditions on rate pressure product (RPP) during ECT. Seizure duration as well as baseline, ictal, and postictal RPP were recorded in 28 patients who received ECT under four stimulus conditions (unilateral threshold, unilateral suprathreshold, bilateral threshold, and bilateral suprathreshold). Seizure duration did not differ between the stimulus conditions. RPP significantly rose from baseline under every stimulus condition. Both ictal and postictal RPP values were different between stimulus conditions (one-way repeated-measure analysis of variance). Pair-wise comparisons showed that unilateral threshold ECT produced significantly lower RPP than unilateral suprathreshold and bilateral suprathreshold ECT conditions. The selective differences in RPP during ECT as well as their correspondence with the known therapeutic potency of ECT under these stimulus conditions suggest that RPP may be a potential index of ECT's therapeutic potency.

Evaluation of rate‐pressure product in obese children

The purpose of this study was to evaluate the relationship between rate-pressure product (RPP) and degree of obesity in 511 obese 7 and 12 year old Chinese children. Obesity was assessed by anthropometry and skinfold thickness. The children were defined obese by relative weight (RW) > 120%. Bodyweight (W) and height (H) were used to derive body mass index (W/H2). Brachial systolic and diastolic pressures in these children were measured by cuff sphygmomanometry. RPP was calculated by the formula: heart rate x mean arterial pressure. More obese children (RW > or = 150%) had greater mean RPP (7 year old: 6389 vs 5976 beats/min x mmHg, P < 0.05; 12 year old: 7024 vs 6686 beats/min x mmHg) than those with RW < 150%. Children in the upper 25 percentiles of RPP had significantly larger BMI (7 and 12 year olds) and RW (12 year olds), thicker biceps, triceps and subscapular skinfolds (12 year olds) (P < 0.01-< 0.05). The results indicate that RPP is, to some extent, related to the degree of obesity in obese children. The differences in RPP may imply varying degrees of hemodynamic stress to the heart. Whether such differences may contribute to the long-term development of cardiovascular morbidity in more obese individuals is uncertain.

Effects of double administration of nicardipine of the cardiovascular response to tracheal intubation in hypertensive patients.

The efficacy of intravenous nicardipine in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation was studied in 20 hypertensive patients. Ten patients received intravenous 1 mg of nicardipine 1 min before induction (N1 group). The other ten received 1 mg of nicardipine 1 min before induction and an additional 1 mg just before laryngoscopy (N2 group). In the N1 group, arterial pressure and heart rate increased significantly after tracheal intubation. In the N2 group, arterial pressure did not increase but heart rate increased more than that in N1 group. There was no significant difference in rate pressure product between the two groups.

Myocardial oxygen supply and lactate metabolism during marked arterial hypoxaemia.

Myocardial O2 delivery and changes in myocardial lactate metabolism during marked hypoxaemia (PaO2 5-5.4 kPa, Sa O2 70-75%) produced by 12% O2 breathing were studied in 12 healthy subjects at rest and during supine exercise up to maximal intensity. Blood for O2 and lactate analyses was sampled from catheters in an artery (a) and the coronary sinus (cs) and coronary sinus blood flow (CSBF) was measured by thermodilution. Lactate metabolism was evaluated in a subgroup of the subjects using i.v. infusion of [14C]lactate. At rest and during submaximal exercise up to heart rate 156 beats min-1 myocardial O2 uptake (MQO2) was maintained at the same level during hypoxaemia as during normoxaemia. This was achieved at rest mainly by a more complete O2 extraction, during exercise entirely by greater CSBF. During maximal exercise CSBF was 35% greater during hypoxaemia than normoxaemia, while there was no difference in cs O2 saturation. Maximal MQO2 was smaller during hypoxaemia than normoxaemia in spite of no difference in rate pressure product. The a-cs difference of lactate was reduced during hypoxaemia and there was a significant myocardial release of lactate, as calculated from [14C]lactate data, during hypoxaemic exercise, but not during hypoxaemic rest or normoxaemic rest and exercise. It is concluded that the heart has a coronary flow reserve of about 35%, which can be utilised under hypoxaemia. When this reserve is insufficient to supply the myocardium with oxygen lactate is produced to cover part of the myocardial ATP regeneration.

Potassium channel activators cromakalim and celikalim (WAY-120,491) fail to decrease myocardial infarct size in the anesthetized canine.

The cardioprotective effects of the K channel activator drugs celikalim (WAY-120,491) and cromakalim were studied in a canine model of myocardial infarction consisting of 90 min of ischemia and 5 h of reperfusion. Intracoronary infusion of cromakalim and celikalim at 0.2 microgram/kg/min beginning 10 min before occlusion of the left circumflex coronary artery and continuing throughout the duration of the reperfusion period appeared to exacerbate ischemic injury. Infarct size (percent of risk area) was 27.7 +/- 5.6% in vehicle control animals (n = 5), 40.3 +/- 6.2% for cromakalim (n = 5) and 55.7 +/- 6.4% (p less than 0.05 vs. vehicle) for celikalim-treated animals (n = 5). When these compounds were administered intravenously, using doses shown to increase total coronary flow in nonoccluded control animals, no exacerbation of ischemic injury was observed. Anatomic infarct size was 32.8 +/- 7.1% for vehicle animals (n = 5) and 32.6 +/- 13.3 and 30.9 +/- 9.8% for cromakalim- (n = 6) and celikalim-treated (n = 5) animals, respectively. Intravenous diltiazem decreased myocardial infarct size to 16.3 +/- 7.3% (n = 5) of area at risk (p = NS vs. vehicle). The anatomic area at risk was similar in all three treatment groups, and no significant differences in rate-pressure product were observed. Results of this study suggest that K-channel-activating drugs such as cromakalim and celikalim may not be effective agents in the acute therapeutic management of myocardial ischemic injury.

Xanthine oxidase inhibition does not limit canine infarct size.

Evidence supporting the role of xanthine oxidase in myocardial reperfusion injury is based on studies with pharmacological interventions used to inhibit enzyme function. Controversy exists, however, regarding the true role of xanthine oxidase in reperfusion injury. This study was performed to determine whether xanthine oxidase inhibition limits myocardial injury due to coronary artery occlusion and reperfusion. Anesthetized dogs underwent coronary artery occlusion (90 minutes) and reperfusion (6 hours). Oxypurinol (28 mg/kg) or amflutizole (30 mg/kg), chemically unrelated inhibitors of xanthine oxidase, or vehicle was infused intravenously 15 minutes before and 3 hours after reperfusion. Regional myocardial blood flow was determined with radiolabeled microspheres. Infarct size was determined with the tetrazolium method. Myocardial infarct size (percent of risk region) was less in oxypurinol-treated dogs, 32 +/- 16%, compared with that of the control group, 46 +/- 15%. Infarct size for the amflutizole-treated dogs, 40 +/- 21%, was not significantly different from that of the control group. There were no differences in rate-pressure product or collateral blood flow to account for differences in infarct size. Uric acid concentration in the coronary venous plasma increased after reperfusion in the dogs treated with vehicle but not in the drug-treated dogs. Xanthine oxidase inhibition was demonstrated in each of the drug treatment groups, but only oxypurinol limited the extent of myocardial injury. Previously reported cardioprotective effects of allopurinol, noted to occur only when the drug was administered chronically, may be related to a property of oxypurinol, a major metabolite of allopurinol. The beneficial effect of oxypurinol is unrelated to inhibition of superoxide formation during xanthine oxidase-catalyzed oxidation of xanthine and hypoxanthine.

A useful canine model of ischemic myocardium with coronary retrograde flow diversion, and its application for the study of allopurinol on myocardial infarct size.

This study was undertaken to evaluate the usefulness of a canine ischemic heart model achieved by coronary retrograde flow (RF) diversion, and to examine the effect of allopurinol on the myocardial infarction. The left anterior descending coronary artery (LAD) was occluded for 90 min followed by 4h reperfusion. Group 1 (n = 9) was a simple LAD occlusion group. In group 2 (n = 8), retrograde flowing blood from the distal of the occluded LAD was simultaneously diverted during LAD occlusion. In group 3 (n = 8), allopurinol was administered 60 min before ischemia with RF diversion followed by its continuous infusion. Infarcted myocardium was determined by triphenyl tetrazolium chloride staining and myocardium at risk by the dye double perfusion technique. RF diversion significantly reduced not only regional myocardial blood flow (RBF) (0.21 +/- 0.05 ml/min/g in group 1 vs 0.05 +/- 0.01 ml/min/g in group 2; p less than 0.05) but also its variance (p less than 0.01). Furthermore, the infarct size (infarct/risk ratio) in the allopurinol treated group was significantly reduced without any significant difference in rate pressure product, risk size or RBF (89.4 +/- 4.0% in group 2 vs 48.9 +/- 4.5% in group 3; p less than 0.01). We conclude that the canine RF diversion model is useful for myocardial infarct study because of the minimizing of the difference of collateral flow, and that canine myocardial xanthine oxidase may produce free radicals which take part in myocardial injury after reperfusion.

The effect of nitroglycerin ointment on exercise-induced angina: A multicenter trial

The efficacy of nitroglycerin ointment was determined by treadmill exercise testing through a randomized, double-blind crossover trial with placebo in 22 patients with chronic stable exertional angina. On different days, 3 cm of nitroglycerin ointment (NGO, 18 mg) and placebo ointment were applied over the epigastric region, followed by the exercise test 1 hour later. The maximal exercise time was 459 +/- 124 seconds after application of placebo and 510 +/- 113 seconds after application of NGO, and the exercise time to 1 mm of ST-segment depression was significantly extended to 297 +/- 110 seconds after placebo and 366 +/- 134 seconds after NGO (p less than 0.01, p less than 0.001, respectively). ST-segment depression at the endpoint of exercise was significantly reduced from 2.4 +/- 1.2 mm to 1.5 +/- 0.7 mm after application of NGO (p less than 0.01). There was no difference in rate-pressure product at the endpoint of exercise between placebo and NGO. Adverse reactions were elicited in 5 of 22 patients. The results of this present study suggest that NGO is effective in the treatment of exertional angina.

COMPARISON OF HAEMODYNAMIC EFFECTS OF METOCURINE AND PANCURONIUM IN PATIENTS WITH CORONARY ARTERY DISEASE

The haemodynamic effects of large bolus doses of metocurine 0.45 mg kg-1 and pancuronium 0.1 mg kg-1 were compared in patients with coronary artery disease anaesthetized with diazepam, anileridine and nitrous oxide. Hypotension occurred more frequently after metocurine and was a result of a decrease in systemic vascular resistance. After pancuronium there was no increase in arterial pressure or heart rate, but a small increase in cardiac index. The decrease in heart rate after metocurine was the principal cause of the statistically significant difference in cardiac index between the two groups. Contrary to previous findings, metocurine did not attenuate circulatory responses to tracheal intubation. During surgical stimulation, two of the 10 patients of the pancuronium group developed significant ST segment depression and three patients had a rate-pressure product greater than 12 000 mm Hg beat min-1. However, the difference in rate-pressure product between the groups was not statistically significant.

Evidence for emotionally-induced coronary arterial spasm in patients with angina pectoris.

Twelve executives with typical angina pectoris, given a 12-minute quiz, designed to be psychologically stressful, responded with ST depressions of greater than or equal to 1.0 mm. Each of these patients was given an exercise tolerance test on an upright bicycle to induce an amount of ST depression equivalent to that observed during the quiz. A statistical analysis was made of the products of the heart rate and the systolic blood pressure (rate-pressure product), at the onset of equivalent ST depression on both tests. At the maximal ST depression during the quiz, the mean rate-pressure product was 181 +/- 64 (SD) X 10(2), and at an equivalent ST depression during exercise it was 225 +/- 54 X 10(2); the mean difference was 44 +/- 40 X 10(2). Inasmuch as the rate-pressure product is an index of myocardial oxygen consumption, the differences in rate-pressure product suggest that myocardial ischaemia occurred at a lower myocardial oxygen consumption during emotional stress than during exercise. If equivalent degrees of ST depression during exercise and the quiz are indicative of equivalent ischaemia, than a relative reduction in coronary blood flow during emotional stress, probably by coronary spasm, may be postulated as the most reasonable explanation for these observations.