Detection of elevated pulmonary capillary wedge pressure in elderly patients with various cardiac disorders by the Valsalva manoeuvre

In the present study, we assessed whether elevated (> or =15 mmHg) PCWP (pulmonary capillary wedge pressure) can be detected using the blood pressure response to the Valsalva manoeuvre in a group of elderly patients with various cardiac disorders, including atrial fibrillation and valvular heart disease, and healthy elderly controls. The Valsalva manoeuvre was performed in 93 patients (71+/-4 years) and 28 healthy controls (70+/-4 years) undergoing right-sided cardiac catheterization. Blood pressure was measured non-invasively with Finapres. PPR (pulse pressure ratio), the ratio of minimum pulse pressure during phase 2 and maximum pulse pressure during phase 1 of the Valsalva manoeuvre, was correlated with PCWP (r=0.63, P<0.001). The area under the receiver operator characteristic curve of PPR with elevated PCWP was 0.85 (P<0.001). For PPR=0.62, sensitivity for elevated PCWP was 80%, specificity was 79%, positive predictive value was 76% and negative predictive value was 83%. Correlation of PPR with PCWP and the ability of PPR to detect elevated PCWP was present in atrial fibrillation, heart failure and valvular heart disease. In conclusion, PPR is a sensitive and specific instrument to diagnose elevated PCWP non-invasively in a large group of elderly patients with various cardiac disorders. This makes the Valsalva manoeuvre a useful non-invasive tool for diagnosing heart failure, applicable in elderly patients with common cardiac disorders, such as atrial fibrillation and valvular heart disease.     

Lower body positive pressure by anti-G garment inflation: a suitable method to increase pulmonary capillary wedge pressure in healthy elderly subjects

In a study on non-invasive assessment of pulmonary capillary wedge pressure (PCWP), we sought a method to increase PCWP non-invasively. We hypothesized that inflation of an anti-G garment was suitable to increase PCWP non-invasively in healthy elderly subjects. In 20 subjects, aged 70 +/- 4 years (mean +/- SD), before, immediately after, and 4 min after anti-G garment inflation to 52 mmHg, PCWP and mean pulmonary artery pressure (MPAP) were measured with a Swan-Ganz catheter, and mean arterial blood pressure (MAP) with Finapres, in supine and semi-recumbent position. Supine, PCWP (mmHg, mean +/- SD) increased from 9.9 +/- 2.1 to 15.5 +/- 3.9** immediately after inflation and 13.4 +/- 3.7** at 4 min; semi-recumbent from 8.9 +/- 2.0 to 17.5 +/- 3.3** and 14.7 +/- 2.9** (*P<0.05, **P< 0.001 versus before inflation). MPAP (mmHg) increased after inflation: supine 16.9 +/- 2.3 to 22.3 +/- 4.6** and 20.6 +/- 3.9** and semi-recumbent 15.7 +/- 2.8 to 24.3 +/- 5.1** and 22.5 +/- 3.5**, suggesting that increased preload was the primary effect of anti-G garment inflation. Supine MAP (mmHg) increased from 96.0 +/- 11.3 to 101.4 +/- 13.4** and 100.5 +/- 12.7* and semi-recumbent from 102.0 +/- 8.9 to 108.3 +/- 11.4** and 106.0 +/- 11.3*, suggesting an effect of increased afterload as well. The latter was supported by an increase in total peripheral resistance (d s cm(-5)) from 1346 +/- 299 to 1441 +/- 384 after 4 min (P = 0.057) and from 1461 +/- 341 to 1532 +/- 406 (P = 0.054), supine and semi-recumbent respectively, while cardiac output remained unchanged. Complications did not occur. We conclude that in healthy elderly subjects, anti-G garment inflation is a safe, non-invasive, method to induce a significant increase in PCWP. Our findings justify its application in future studies in which non-invasive temporary increase in PCWP is required.     

Cardiovascular response to coughing: its value in the assessment of autonomic nervous control

1. The relationship between blood pressure and heart rate responses to coughing was investigated in 10 healthy subjects in three body positions and compared with the circulatory responses to commonly used autonomic function tests: forced breathing, standing up and the Valsalva manoeuvre. 2. We observed a concomitant intra-cough increase in supine heart rate and blood pressure and a sustained post-cough elevation of heart rate in the absence of arterial hypotension. These findings indicate that the sustained increase in heart rate in response to coughing is not caused by arterial hypotension and that these heart rate changes are not under arterial baroreflex control. 3. The maximal change in heart rate in response to coughing (28 +/- 8 beats/min) was comparable with the response to forced breathing (29 +/- 9 beats/min, P greater than 0.4), with a reasonable correlation (r = 0.67, P less than 0.05), and smaller than the change in response to standing up (41 +/- 9 beats/min, P less than 0.01) and to the Valsalva manoeuvre (39 +/- 13 beats/min, P less than 0.01). 4. Quantifying the initial heart rate response to coughing offers no advantage in measuring cardiac acceleratory capacity; standing up and the Valsalva manoeuvre are superior to coughing in evaluating arterial baroreflex cardiovascular function.     

Effect of naloxone on the defective autonomic control of heart rate in uraemic patients

The role of endogenous opioids on the reflex cardiovascular control of chronic uraemic patients was investigated. The opiate antagonist naloxone administered intravenously caused a significant increase in the abnormal Valsalva manoeuvre ratio in nine chronic uraemic patients, but it had no effect in six diabetic patients with normal renal function, whose response to the Valsalva manoeuvre was similar to that of chronic uraemic patients. Naloxone had no effect in eight normal subjects. The increase in the Valsalva ratio observed in uraemic patients was due to restoration of the parasympathetically mediated reflex bradycardia of the release phase of the manoeuvre. Naloxone did not modify supine and standing blood pressure and heart rate in any group. Endogenous opioids may be involved in the defective autonomic control of heart rate in uraemic patients.     

Cardiac autonomic dysfunction in obese subjects

1. The prevalence of cardiac autonomic alterations was evaluated in 23 obese subjects with body mass index 37.2 +/- 3.03 kg/m2 (mean +/- SD), compared with 78 controls with body mass index 22.5 +/- 2.6 kg/m2 (P less than 0.001). 2. Cardiac autonomic function was assessed by four standard tests (heart rate response to deep breathing and to the Valsalva manoeuvre, systolic blood pressure fall after standing and diastolic pressure rise during handgrip) and by the cross-correlation test, a new method of computerized analysis of respiratory sinus arrhythmia based on spectral analysis of electrocardiographic and respiratory signal. 3. Considering tests indicative of parasympathetic function, only the heart rate response to the deep breathing and the cross-correlation test were significantly lower in the obese than in the control group [deep breathing = 13.95 +/- 8.65 beats/min (mean +/- SD) vs 24.5 +/- 7.65, P less than 0.001; cross-correlation 4.28 +/- 0.74 units vs 5.14 +/- 0.63, P less than 0.001]. Deep breathing and/or cross-correlation were abnormal in 10 (43.5%) obese subjects (deep breathing: seven subjects, cross-correlation: eight subjects). No significant difference between groups was found for the response to the Valsalva manoeuvre: the Valsalva ratio was 1.69 +/- 0.45 in obese subjects and 1.88 +/- 0.33 in controls (P = NS). The Valsalva ratio was abnormal in three obese subjects. 4. No significant differences were found between groups for tests indicative of sympathetic function.(ABSTRACT TRUNCATED AT 250 WORDS)     

Short- and long-term reproducibility of autonomic measures in supine and standing positions

Autonomic nervous tests and heart rate variability (HRV) have been used to assess cardiac autonomic function and to evaluate long-term prognosis. The aim of this study was to evaluate the short- and long-term reproducibility of HRV parameters and autonomic nervous tests according to body position (supine or standing). The study group consisted of 26 healthy subjects. Autonomic nervous tests and HRV were performed twice during the day and the results were averaged. The protocol was then repeated 3 days after each examination and also after 6 and 24 months. Autonomic nervous tests included deep breathing, Valsalva manoeuvre and isometric muscle exercise (handgrip), as well as blood pressure and heart rate in response to standing. ECG recordings were taken for 10 min during spontaneous breathing for HRV analysis. We found that the reproducibility of some parameters of the autonomic nervous test were independent of body position [E/I ratio (heart rate response to deep breathing)], whereas other parameters were dependent on body position (Valsalva manoeuvre and blood pressure response to sustained handgrip). In addition, within-day measurements of those parameters varied from non-reproducible (Valsalva ratio, handgrip and blood pressure response to standing) to moderately reproducible [E/I ratio and 30/15 ratio (heart rate response to standing)]. Among the HRV parameters, we found that total power (TP), low (LF)- and high (HF)-frequency were reproducible not only for measurements made within the same day, but also during short- and long-term observations, and only the LF/HF ratio was dependent on body position. We conclude that only a few autonomic nervous tests are reproducible in the short- and long-term. Because HRV parameters obtained during spontaneous respiration showed high reproducibility for measurements made within the same day as well as in the short- and long-term, they should be used instead of autonomic nervous tests when long-term observations are carried out in a healthy population.     

Orthostatic circulatory control in the elderly evaluated by non-invasive continuous blood pressure measurement

1. Continuous orthostatic responses of blood pressure and heart rate were measured in 40 healthy and active elderly subjects over 70 years of age in order to assess the time course and rapidity of orthostatic cardiovascular adaptation in old age. 2. During the first 30 s (initial phase) the effects of active standing and passive head-up tilt closely resembled those observed earlier in younger age groups. Standing up was accompanied by a drop (mean +/- SD) in systolic and diastolic blood pressures of 26 +/- 13 mmHg and 12 +/- 18 mmHg, respectively, at around 10 s, and a subsequent rise up to 11 +/- 17 mmHg and 8 +/- 6 mmHg above supine values at around 20 s. The drop in blood pressure upon standing was accompanied by a transient increase in heart rate with a maximum of 13 beats/min, followed by a gradual decrease to 7 beats/min above supine levels. These characteristic transient changes were absent upon a passive head-up tilt. 3. After 1-2 min of standing (early steady-state phase) diastolic blood pressure and heart rate increased significantly after active and passive postural changes. On average, for all subjects systolic blood pressure tended to increase from control during 5-10 min standing, reaching a significant difference at 10 min. During standing, the largest increases in systolic blood pressure were found in subjects with the lowest supine blood pressures. 4. In conclusion, for the investigation of orthostatic circulatory responses in elderly subjects the following factors have to be taken into account: active versus passive changes in posture, the timing of the blood pressure reading, and the level of supine blood pressure.     

Intra-individual variability in postural blood pressure in the elderly

Orthostatic hypotension, an age-related phenomenon, has been associated with hypertension and body weight variability. To evaluate the relative contributions of blood pressure elevation and abnormalities in extracellular volume regulation to orthostatic hypotension, elderly institutionalized subjects (mean age = 87 +/- 7 years), taking no cardiovascular medications, underwent measurement of body weight (n = 15) and first morning supine and standing blood pressures (n = 19), 12-13 times per subject over a 2-4 week period. There was a wide day-to-day variability in postural systolic blood pressure change (coefficient of variation = 533%) and a strong negative correlation between each day's postural change in systolic blood pressure and basal supine blood pressure (r = -0.55, P less than 0.0001). There was no association between postural blood pressure change and heart rate response or body weight changes, which were very small over the duration of the study (coefficient of variation = 0.6%). Elderly individuals have intact homeostatic mechanisms for the control of standing pressure when basal blood pressure is normal. Postural hypotension in the elderly is a variable phenomenon related to elevations in basal blood pressure.     

Effect of intermediate-dose naloxone on cardiovascular and sympathoneural adjustments to exercise.

The effects of intermediate-dose naloxone on sympathetic nerve activity and cardiovascular adjustments to exercise were examined in two series of experiments. In the first series 10 normal male volunteers, mean age 28 +/- 5 (SD) years received i.v. naloxone, mean 0.28 +/- 0.6 mg/kg in 0.1 mg/kg aliquots 60-90 min after 45 min of submaximum treadmill exercise. Naloxone had no detectable effect on supine blood pressure, heart rate, plasma norepinephrine, or epinephrine concentrations or muscle sympathetic nerve burst frequency at rest or during the strain phase of the Valsalva manoeuvre, but decreased slightly sympathetic burst incidence at rest (p less than 0.05). In the second study, 8 of these subjects repeated the exercise protocol 15 to 20 min after 0.1 mg/kg i.v. naloxone. Supine blood pressure, heart rate, plasma norepinephrine and epinephrine concentrations before and 15 min after naloxone were virtually identical. A comparison of results from both study days did not reveal a naloxone effect on blood pressure during or up to 60 min after exercise, whereas the heart rate response to exercise was attenuated (p less than 0.002). Intermediate-dose naloxone has no apparent effects on blood pressure during and after exercise, attenuates the chronotropic response to exercise, and has only modest inhibitory effects on muscle sympathetic nerve activity.     

Autonomic responses to the Valsalva manoeuvre in healthy subjects

Summary. To assess normal autonomic haemodynamic responses to the Valsalva manoeuvre, 158 healthy unmedicated subjects, aged 25–60 years, were examined. For measurement of beat-to-beat blood pressure on a finger, the Finapres instrument was used. Phase-to-phase changes in instantaneous blood pressure and heart rate and the latency response between the end of a Valsalva manoeuvre and points on the resultant blood pressure and heart rate were calculated, and the reference limits for various indices were determined. Sex had no or only marginal effect on blood pressure or heart rate responses or latencies. Ageing was accompanied by a smaller decrease and smaller partial recovery of blood pressure during the strain, with attenuation of reflectory bradycardia, and lengthening of the latencies. It is concluded that age-related reference values should be applied in the interpretation of the Valsalva responses. The following responses should be analysed: mean blood pressure decrease and partial recovery during the strain (adrenergic vasoconstrictor function), reflectory bradycardia after the strain (parasympathetic function), and the latencies (sympathetic and parasympathetic function).     

Effects of a brief Valsalva manoeuvre on hemodynamic response to strength exercises

Strength training is a recommended measure against loss of strength and muscle mass because of age- or illness-induced inactivity. Strength exercises may impose heavy cardiovascular load by increasing heart rate and blood pressure. To increase strength efficiently, a heavy load has to be applied; this, however, leads to a spontaneous Valsalva manoeuvre, which additionally raises blood pressure. Avoidance of this manoeuvre is recommended. If the additional rise in arterial blood pressure caused by Valsalva manoeuvre is smaller than intrathoracic or intracranial pressures during this manoeuvre, Valsalva manoeuvre may actually protect arteries located in the thorax and in the brain by diminishing transmural pressure acting across these vessels. Effect of controlled breathing or brief Valsalva manoeuvre on arterial pressure at rest and during knee extension against 15-repetition maximum resistance was evaluated. In 12 healthy young men blood pressure was measured continuously and non-invasively, knee angle, speed of respiratory air or mouth pressure (MP) were continuously registered. Each combination of respiratory and exercise manoeuvres was repeated six times, for every of last three repetitions peak and trough systolic and diastolic pressure were determined. Strength exercises elevated peak pressures more than trough pressures, systolic more than diastolic. Valsalva manoeuvre increased only peak systolic and peak diastolic pressure. This increase was in average lesser than MP, thus rendering an argument in favour of protective role of brief Valsalva manoeuvre because of decline in transmural pressure acting on thoracic and possibly cerebral arteries. However, there was strong individual variability, and in few instances, arterial pressure increased because of brief Valsalva manoeuvre more than MP; thus in some subjects, the manoeuvre might enhance transmural pressure acting on thorax arteries.     

冠心病患者等长收缩运动时肺毛细血管嵌顿压升高的机理

用左右心导管观察10例典型劳力性心绞痛患者在极量等长收缩运动(IE)和IE加乏氏动作时的血液动力学反应及临床表现,并以冠状动脉气囊扩张成形术建立急、慢性冠状动脉供血不足以及正常冠状动脉的模型。结果表明进行极量前臂等长收缩运动和乏氏动作时肺毛细血管嵌顿压升高,其机理可能与胸腔内压的增高和主动脉压的增高有关而与心肌缺血无关。这解释了为何等长收缩运动试验的敏感性不高,也说明对心脏患者禁止IE和乏氏动作的概念应该加以修正。     

Power spectral analysis of heart rate and diastolic blood pressure variability in migraine with and without aura

Autonomic function in migraineurs during headache-free periods was studied by means of cardiovascular reflexes and power spectral analysis of heart rate and diastolic blood pressure variability. We examined 56 patients: 37 suffering from migraine without aura and 19 from migraine with aura. Cardiovascular responses to the tilt test and Valsalva manoeuvre showed a normal function of the overall baroreceptor reflex arc. Normal heart rate responses to valsalva manoeuvre and deep breathing suggested an intact parasympathetic function. Power spectral analysis of both heart rate and diastolic blood pressure variability in basal conditions and during orthostatic test showed similar sympathovagal interactions modulating cardiovascular control in migraine patients and in controls.     

The influence of posture,Valsalva manoeuvre and coughing on portal hypertension in cirrhosis

Percutaneous transhepatic catheterization of the portal venous system and pressure readings were performed in nineteen patients with cirrhosis of the liver and bleeding varices. Portal pressures were recorded in awake and mobile patients in supine, sitting and standing position, during sleep, ingestion of food, Valsalva manoeuvre and coughing. No significant differences were recorded in the different postures, during sleep or food intake. Four patients with hepatofugal portal blood flow had, however, lowest pressure in standing position. During Valsalva manoeuvre portal pressure was doubled, and it became fourfold during coughing. Elevations of this magnitude have not previously been reported. A relationship was found between portal pressure and size of varices.     

Age-related diminution of the cardiovascular autonomic responses: diagnostic problems in the elderly

Summary. To study the usefulness of standard cardiovascular autonomic reflex tests in the elderly, 224 healthy controls and 49 aged diabetic patients were examined. Based on the data obtained from healthy controls, age-related reference values for several autonomic indices were calculated and their usefulness was tested with aged diabetic patients. It was found (1) that in elderly subjects (aged 50 years) the indices based on heart rate differences are more suitable for the assessment the autonomic parasympathetic control than indices based on R/R interval ratios, (2) that the tests (and indices) of choice in the elderly subjects are the Valsalva manoeuvre (Valsalva difference and tachycardia difference) and the active orthostatic test (Max-Rest difference, immediate and later change in systolic blood pressure), (3) that the usefulness of the deep breathing test is limited in the elderly, (4) that such commonly used indices as the Valsalva ratio and the Max/Min ratio in orthostatic test are not useful in the elderly, and (5) that the isometric handgrip test is of little use in the assessment of the autonomic function in the elderly. In conclusion, standard cardiovascular autonomic reflex tests can be used in the assessment of autonomic function to some extent also in the elderly subjects. However, one must bear in mind the limitations in their applicability in that age group.,     

The influence of posture, Valsalva manoeuvre and coughing on portal hypertension in cirrhosis

Percutaneous transhepatic catheterization of the portal venous system and pressure readings were performed in nineteen patients with cirrhosis of the liver and bleeding varices. Portal pressures were recorded in awake and mobile patients in supine, sitting and standing position, during sleep, ingestion of food, Valsalva manoeuvre and coughing. No significant differences were recorded in the different postures, during sleep or food intake. Four patients with hepatofugal portal blood flow had, however, lowest pressure in standing position. During Valsalva manoeuvre portal pressure was doubled, and it became fourfold during coughing. Elevations of this magnitude have not previously been reported. A relationship was found between portal pressure and size of varices.     

In aged men,central vessel transmural pressure is reduced by brief Valsalva manoeuvre during strength exercise

A brief Valsalva manoeuvre, lasting 2–3 s, performed by young healthy men during strength exercise reduces transmural pressure acting on intrathoracic arteries. In this study, we sought to verify this finding in older men. Twenty normotensive, prehypertensive and moderately hypertensive otherwise healthy men 46–69 years old performed knee extensions combined with inspiration or with brief Valsalva manoeuvre performed at 10, 20 and 40 mmHg mouth pressure. Same respiratory manoeuvres were also performed at rest. Non‐invasively measured blood pressure, knee angle, respiratory airflow and mouth pressure were continuously registered. In comparison to inspiration, estimated transmural pressure acting on thoracic arteries changed slightly and insignificantly during brief Valsalva manoeuvre at 10 and 20 mmHg mouth pressure. At 40 mmHg mouth pressure, transmural pressure declined at rest (?8·8 ± 11·4 mmHg) and during knee extension (?12·1 ± 11·9 mmHg). This decline ensued, as peak systolic pressure increase caused by this manoeuvre, was distinctly <40 mmHg. Only a main effect of mouth pressure was revealed (P<0·001) and neither exercise nor interaction between these factors, what suggests that transmural pressure decline, depended mainly on intrathoracic pressure developed during brief Valsalva manoeuvre. Resting blood pressure did not influence the effect of brief Valsalva manoeuvre on transmural pressure.     

Systemic vascular resistance during brief withdrawal of angiotensin converting enzyme inhibition in heart failure

We tested the hypothesis that moderate increases in endogenous angiotensin II (Ang II) concentrations, induced by withdrawal of angiotensin converting enzyme inhibition (ACE-I) in patients with compensated heart failure (HF) on chronic medical therapy, do not increase or impair control of systemic vascular resistance (SVR). SVR was determined in supine and seated positions in 12 HF patients [NYHA class II-III; ejection fraction=0.29 +/- 0.03 (mean +/- SE)] and 9 control subjects. HF patients were investigated during high (n=11; withdrawal of ACE-I treatment for 24 h) and low (n=9; sustained ACE-I therapy) endogenous plasma Ang II concentrations. Withdrawal of ACE-I therapy in HF caused moderately increased Ang II concentrations of 30 +/- 5 pg/ml compared with 12 +/- 2 pg/ml in controls (p<0.05 vs. HF patients). Despite this, SVR was similar in HF (supine: 1503 +/- 159; seated: 1957 +/- 262 dyn s/cm5, p<0.05 vs. supine) and controls (supine: 1438 +/- 104; seated: 1847 +/- 127 dyn s/cm5, p<0.05 vs. supine). During sustained ACE-I therapy in HF, plasma Ang II concentrations were lower (6 +/- 2pg/ml, p<0.05 vs. withdrawal of ACE-I in HF) with no effect on supine SVR. However, the posture-induced increase in SVR in response to the seated position was attenuated. In conclusion, brief moderate increases in circulating plasma Ang II concentrations in compensated HF do not increase SVR compared to control subjects or impair control of SVR in response to a posture change.     

Tachycardia and coronary blood flow: non-invasive estimation during Valsalva manoeuvre and exercise

Summary. Simultaneous changes in cycle length and coronary blood flow were studied during Valsalva manoeuvre and supine cycloergometer exercise test in 10 male patients (mean age 4812 years) who had successfully undergone myocardial revascularization by surgical anastomosis of the left internal mammary artery on the left anterior descending coronary artery. Blood velocity curves in the left internal mammary artery were obtained by a non-invasive continuous-wave Doppler probe at rest, in the last phase of the expiratory effort of the Valsalva manoeuvre and at the maximum load attained during the exercise test. Mean arterial pressure by sphygmomanometer, and cardiac cycle length on the basis of Doppler recording were measured. Mean blood velocity, the length of the blood column entering the coronary bed at each cycle (cardiac cycle times mean velocity), an index of blood cell acceleration (the ratio of mean velocity to cardiac cycle), and an index of coronary resistance (the ratio of mean pressure to mean velocity), were calculated. For approximately the same change in cycle length, coronary resistance decreased in exercise, with an increased mean velocity, but increased in Valsalva, with no changes in mean velocity. The length of the blood column entering the coronary bed at each cycle was unchanged in exercise, with a marked increase in the acceleration index, while it decreased in Valsalva. Therefore, we hypothesize that tachycardia has a limiting effect on sympathetic coronary constriction in Valsalva when cardiac external work is decreased, and an additional vasodilatory effect on coronary bed in exercise when external work is increased.,     

Cardiovascular reflex responses in Bangladeshi and European subjects.

1. Cardiovascular responses to three different interventions, namely the Valsalva manoeuvre, deep breathing and a cold stimulus on the face, were studied in two ethnic groups (European and Bangladeshi) that have been shown to differ in the prevalence of hypertensive-vascular disease. The data obtained consisted of systolic blood pressure, diastolic blood pressure, mean blood pressure, heart rate measured by using a beat-by-beat non-invasive blood pressure monitor (the Finapres), forearm blood flow determined by venous occlusion plethysmography, and calculated forearm vascular resistance. 2. The resting haemodynamic status was similar in European and Bangladeshi subjects. However, Bangladeshi subjects showed a greater increase in heart rate, but only after 20 s into the Valsalva manoeuvre, and greater overshoots in mean blood pressure after the manoeuvre than the European subjects. Furthermore, after cold face stimulation the fall in forearm vascular resistance to baseline levels was delayed in Bangladeshi subjects relative to that in the European subjects. 3. There were no inter-group differences in the reflex bradycardia relative to mean blood pressure or in the cardiac baroreflex sensitivity estimated from systolic blood pressure and pulse interval after the Valsalva manoeuvre. In addition, values for the mean difference between maximum and minimum pulse intervals during deep breathing did not differ in Bangladeshi and European subjects. 4. These findings together suggest that, although cardiac vagal reflex responses appear similar in the two groups, sympatho-adrenal influences on the heart and vasculature may be greater in Bangladeshi subjects than in European subjects.