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At least 1,153 records · Page 64Linked to original sources
PubMed2000

[Local and general rest in the treatment of common low back pain].

The routine prescription of rest for patients with common low back pain is now widely questioned. Local rest using lumbar corsets and back supports is useful only in case of acute or extreme low back pain, in particular if trauma is involved. In chronic low back pain, such support should be used only to facilitate pursuit of an at-risk professional activity. In acute low back pain, general rest should be indicated by the intensity of pain and not prescribed as a treatment itself. General prolonged rest in acute low back pain has now been demonstrated to entail nefarious long-term effects. In the patient with chronic low back pain, general rest will favour loss of physical condition and exacerbate the difficulties socio-professional rehabilitation.

Acute Disease↗
PubMed2001

Usefulness of rest and forced perfusion scintigraphy (SPECT) to evaluate cardiotoxicity in acute carbon monoxide poisoning.

The aim of the study was to evaluate myocardial perfusion in acute carbon monoxide poisoned patients using rest and stress Tc 99m-MIBI SPECT scintigraphy. There were 29 study patients (15 men and 14 women) aged from 14 to 46 years poisoned acutely with CO at home. Measurement of COHb, blood lactate level, duration of exposure and ECG examination were performed on admission to the Clinic. The enzymes activity (ALT, AST, CBK) were evaluated after 24 hours. The first rest Tc99m-MIBI SPECT was performed in all patients two to five days after intoxication. Fifteen of the patients underwent the control examination: stress and rest scintigraphy six months after CO exposure. Moving track exercise according to the Bruce protocol was used in each the patients. The control rest scintigraphy was performed 48 hours after exercise. Abnormal, differently intensified scans were noted in all the subjects: 5 patients had a I degree of pathological changes, 7 patients had II degree, 16--III degree and 1 patient had a IV degree of pathological changes. In 14 of the patients with pathological scintigraphic scans the normal EKG curves were noted. The mean COHb level was 35.0 +/- 7.22%, the blood lactate concentration was 4.4 +/- 3.7 mmol/L. The average duration of exposure was 108.4 +/- 163.9 min. Effort related ischemia was not noted in 10 of the patients who underwent control examination. An improvement in rest scintigraphic scans was stated in 12, and no changes were observed in 3 of the controlled patients. Deterioration was not found in any patient. No correlation between ECG results and scintigraphic image of myocardium was found. Tc 99m-MIBI SPECT scintigraphy is a more sensitive method than electrocardiography and measurement of enzymes activity for the evaluation of CO cardiotoxicity in acute poisoning. The method enables evaluation of the localization and disease extent.

Adolescent↗
PubMed1997

Effects of 20 days of bed rest on physiological cross-sectional area of human thigh and leg muscles evaluated by magnetic resonance imaging.

The present study was to investigate the effects of 20 days of bed rest on morphological characteristics of lower limb skeletal muscles. Ten sedentary volunteers (5 males and 5 females) were participating in this study. Magnetic resonance imaging techniques were used to measure the physiological cross-sectional areas (PCSAs) of the major muscles and muscle groups of the lower limb. Consecutive images were taken from the right thigh and leg of subjects, and muscle volumes (MV), muscle length, and fiber length were calculated. PCSA of each muscle was determined as MV times the cosine of the angle of fiber pennation divided by fiber length. PCSA of knee extensor and flexor muscles were significant reduced during and after bed rest. MV and PCSA of individual muscles in the knee extensors decreased by -5.1 % to -8.0%. In knee flexors, MV and PCSA in biceps femoris (long head), semitendinosus, semimembranosus, and sartorius decreased during and after bed rest. MV and PCSA in medial and lateralis [correction of andateralis] gastrocnemius, and soleus were remarkably reduced by -9.4 to -10.3% after bed rest. The results suggest that there is a great variability of muscle atrophy in the lower limb muscle groups or individual muscle after bed rest and that the plantar flexors primarily affected.

Adult↗
PubMed1997

Effects of the renin-angiotensin-aldosterone system on the cardiovascular system during 20-days bed rest.

Long term change of renin-angiotensin-aldosterone system (RAAS) induced by bed rest and its effects on cardiovascular system are still controversial. The purpose of this study was to obtain a general conclusion on these questions by analyzing our two 20-days horizontal bed rest experiments in past two years with 18 subjects. Plasma renin activity and aldosterone were consistently increased during the bed rest, but angiotensin II was increased only during the early days. Decrease in urinary sodium excretion and increase in urinary potassium excretion were observed during day 3-8 and day 7-12, respectively. Mean arterial pressure increased during day 3-8. Pulse pressure was returned to pre-bed rest level by day 10 after an initial decrease. All these results indicated an activated RAAS and its active effects on cardiovascular and overall fluid regulating systems during our horizontal bed rest studies. Direct effect of change in gravitational force on renal pressure-sensitive cells or effects related to physical inactivity may explain our results.

Adult↗
PubMed1998

Free radicals generation by granulocytes from men during bed rest.

Phagocytes (granulocytes and macrophages) are one of the most important sources of reactive oxygen species (ROS) in the human body. A stimulated phagocyte reaches within a dozen of seconds the functional state known as the respiratory burst. This phenomenon includes three interrelated processes: 1) a several fold increase in the oxygen uptake, 2) generation of large amounts of ROS, and 3) stimulations of glucose metabolism via the pentose phosphate shunt. The main ROS generated during phagocytosis is the superoxide radical anion O2-. The reaction of dismutation of O2- generates hydrogen peroxide (H2O2). O2- and H2O2 do not have strong cytocidal proerties but are supbstrates for the generation of more active biologically ROS, especially the hydroxyl radical (OH) and hypochlorous acid (HOCl). A stimulated phagocyte (especially neutrophil) generates also vast amounts of nitric oxide (NO-). NO- may react with the superoxide radical anion forming peroxynitrate (ONOO-). Reactivity of ONOO- is comparable to that of the hydroxyl radical. ONOO- plays probably a very important role in the so-called oxygen-dependent killing mechanisms during phagocytosis. The role of NO- in the process of phagocytosis is unclear. However, NO-, apart from other biological functions, inhibits aggregation and adhesion of blood platelets. Morevover, it seems to participate in the slefregulation of granulocyte cativity (probably limiting excessive inflammative reaction). Excess of ROS generated by phagocytes may damage biologically important macromolecules. Membrane lipids are particularly vulnerable to peroxidation. It leads to alterations in membrane fluidity and permeability. ROS excreted to the environment of a phagocyte may impair functions of other morphotic elements of blood (erythrocytes and thromobcytes) in this way. Bed rest covers two conditions: 1) limitation of motoric activity (hypodynamia) and 2) restraining the pressure on bones along parallelly to their long axes (hypogravia). Under bed rest conditions organism is subject to many harmful changes. I.a., bed rest affects also leukocyte functions. However, we were not aware of any sutdies concerning the effect of bed rest on the respiratory burst of granulocytes. This study was aimed at an examination of the effect of bed rest on the generation of O; and H2O2 by neutrophils (PMNL).

Adult↗
PubMed1999

Plasma myostatin-immunoreactive protein is increased after prolonged bed rest with low-dose T3 administration.

It has been hypothesized that myostatin, a newly identified member of the transforming growth factor-beta (TGF-beta) family of proteins, acts as a negative regulator of skeletal muscle growth. Because bed rest induced muscle atrophy results from a decreased rate of muscle protein synthesis, we hypothesized that circulating levels of myostatin would be increased following prolonged bed rest. Twelve men (age, 35.8 +/- 4.6 yr; height, 175.7 +/- 2.3 cm; weight, 74.8 +/- 3.5 kg; mean +/- SE) were confined to bed for 25 days at 6 degrees head-down tilt while receiving triiodothyronine (T3; 50 micrograms/day) to accelerate protein loss. Total lean body and appendicular skeletal muscle mass were determined by dual energy x-ray absorptiometry (DEXA) before and after the bed rest period. Plasma myostatin-immunoreactive protein was measured in blood samples obtained after an overnight fast 5 days prior to, and on the 25th day of bed rest. Lean body mass decreased an average 2.2 kg (p < 0.0001). Appendicular skeletal muscle accounted for a majority of the lean body mass loss. On day 25 of bed rest, plasma myostatin-immunoreactive protein was 12% higher (p = 0.01) than measured at baseline. These data support the idea that myostatin regulates muscle growth in humans and that it may be a novel target for interventions aiming to reduce space flight induced muscle atrophy.

Adult↗
PubMed2003

Pregnancy outcome of threatened abortion with subchorionic hematoma: possible benefit of bed-rest?

BACKGROUND: Bleeding in the first trimester of pregnancy is a common phenomenon, associated with early pregnancy loss. In many instances a subchorionic hematoma is found sonographically. OBJECTIVE: To evaluate the possible benefit of bed-rest in women with threatened abortion and sonographically proven subchorionic hematoma, and to examine the possible relationship of duration of vaginal bleeding, hematoma size, and gestational age at diagnosis to pregnancy outcome. METHODS: The study group consisted of 230 women of 2,556 (9%) referred for ultrasound examination because of vaginal bleeding in the first half of pregnancy, who were found to have a subchorionic hematoma in the presence of a singleton live embryo or fetus. All patients were advised bed-rest at home; 200 adhered to this recommendation for the duration of vaginal bleeding (group 1) and 30 continued their usual lifestyle (group 2). All were followed with repeated sonograms at 7 day intervals until bleeding ceased, the subchorionic hematoma disappeared, or abortion occurred. The groups were compared for size of hematoma, duration of bleeding, and gestational age at diagnosis in relation to pregnancy outcome (spontaneous abortion, term or preterm delivery). RESULTS: The first bleeding episode occurred at 12.6 +/- 3.4 weeks of gestation (range 7-20 weeks) and lasted for 28.8 +/- 19.1 days (range 4-72 days). The women who adhered to bed-rest had fewer spontaneous abortions (9.9% vs. 23.3%, P = 0.006) and a higher rate of term pregnancy (89 vs. 70%, P = 0.004) than those who did not. There was no association between duration of vaginal bleeding, hematoma size, or gestational age at diagnosis of subchorionic hematoma and pregnancy outcome. CONCLUSIONS: Fewer spontaneous abortions and a higher rate of term pregnancy were noted in the bed-rest group. However, the lack of randomization and retrospective design of the outcome data collection preclude a definite conclusion. A large prospective randomized study is required to confirm whether bed-rest has a real therapeutic effect.

Abortion, Spontaneous↗
PubMed2003

Prognostic value of combined assessment of regional left ventricular function and myocardial perfusion by dobutamine and rest gated SPECT in patients with uncomplicated acute myocardial infarction.

UNLABELLED: Gated SPECT allows combined assessment of regional myocardial perfusion and left ventricular function. The aim of this study was to address the prognostic value of gated SPECT performed during dobutamine stress testing and during rest on patients with acute myocardial infarction treated with thrombolysis. METHODS: Eighty-eight consecutive patients with uncomplicated acute myocardial infarction who underwent predischarge (3-7 d after admission) dobutamine (5-40 microg/kg of body weight per minute in 3-min dose increments) and rest gated (99m)Tc-sestamibi SPECT were followed for a mean of 48 mo (range, 4-64 mo). RESULTS: Eighteen cardiac events (8 cardiac deaths and 10 nonfatal myocardial infarctions) occurred. Ischemia at dobutamine SPECT imaging (summed difference score or=>or= 1) was present in 60% of the patients. In patients without ischemia, there was a lower event rate (11%), compared with patients with mild ischemia (18%) and moderate-to-severe ischemia (40%) (P < 0.05). Patients with events showed also a higher summed difference score, compared with patients without events (2.3 +/- 1.6 vs. 1.3 +/- 1.6, P < 0.05). Independent predictors of events were the number of segments with preserved (99m)Tc-sestamibi uptake at rest and the number of akinetic or dyskinetic segments with preserved (99m)Tc-sestamibi uptake and preserved wall thickening (global chi(2) of the model, 13.6; P < 0.01). The assessment of the incremental prognostic value of variables added sequentially showed that the addition of the summed difference score added information to perfusion status at rest (P < 0.05). Combined assessment of regional myocardial perfusion and left ventricular function at rest further improved the model (P < 0.05). CONCLUSION: The present study indicated that predischarge (99m)Tc-sestamibi gated SPECT gives prognostic information on patients recovering from acute myocardial infarction. Patients with preserved systolic wall thickening should be regarded as a high-risk subgroup, requiring closer follow-up for appropriate treatment.

Dobutamine↗
PubMed1992

[Accommodative resting position and the effect of viewing distance on after-effects of accommodation and the pupil].

The resting position of accommodation is determined by the equilibrium established between sympathetic and parasympathetic tone. To accommodate for near objects is brought about by excitation of the parasympathetic, and distant objects call for excitation of the sympathetic system. To investigate accommodation and pupil after-effects following the 10 min visual task with stereoscopic three dimensional image, the measurements of the dynamic responses of accommodation and pupil were made. When the subjects worked at 0.4 m (closer than their resting state) and at 1 m corresponded to their resting positions, the response delay in accommodative relaxation occurred in each condition. When they worked at outside their resting position (1.5 m and 3 m viewing distances), the significant response delay in contraction in the groups of 1.5 m and 3 m, and the increases of accommodation error and the area of miosis were shown. There was a fact that the after-effect on accommodation and pupillary function was different between in the case of tasks given inside and outside their resting positions.

Accommodation, Ocular↗
PubMed1991

[Screening of single doses of the main antihypertensive drugs at rest and during various exercise tests in patients with hypertension].

The single doses of three reference antihypertensive drugs: corinfar (20 mg), anapriline (80 mg), and hypothiazide (50 mg) were screened on day 5 of drug administration at rest and during paired isometric and dynamic exercises in comparison to placebo. There was a significant decrease in blood pressures: systolic (SBP), diastolic (DBP), and mean (MBP) (p less than 0.01-0.001) at rest and during isometric and dynamic exercises after single doses of corinfar and hypothiazide versus placebo. A single dose of anapriline resulted in a significant reduction in SBP and MBP at rest and during dynamic exercise (p less than 0.05-0.001), in DBP at rest (p less than 0.05) and in an insignificant decrease in SBP, DBP, and MBP during isometric exercise and DBP during dynamic exercise. The agents were graded in terms of the effect of placebo from the mean group and individual hypotensive effects (by each blood pressure parameter). The resting dynamic exercise failed to yield some new evidence for determining the efficacy of corinfar and hypothiazide, whereas it was informative for anapriline with regard to SBP. With respect to SBP, DBP, and MBP, isometric exercise was informative for hypothiazide.

Adult↗
PubMed1991

Effects of 30-h sleep loss on cardiorespiratory functions at rest and in exercise.

The effects of 30-h sleep deprivation on cardiorespiratory function either at rest or in exercise were studied in 15 young healthy male volunteers. All subjects performed 1-min incremental exercise tests on a bicycle ergometer until exhaustion and endurance exercise tests at 3/4 of their maximal work rates. Arterialized venous blood samples were withdrawn at rest and during exercise tests to investigate the influence of sleep loss on blood gases. In addition, resting plasma catecholamine levels were also measured in ten subjects. The results showed that 1) resting heart rate, plasma catecholamine levels, and blood pH were decreased while minute ventilation (VI) and CO2 production (VCO2) were increased after 30 h of sleep loss (P less than 0.05), and 2) the maximal exercise performance was reduced by sleeplessness, as indicated by the decreases in the maximal heart rate, peak VI, peak VCO2, peak O2 consumption, and time to exhaustion (P less than 0.05). However, no significant changes in exercise endurance, arterialized venous pH, and PCO2 were found in exercise after sleep deprivation either. We therefore conclude that 30-h sleep loss alters cardiorespiratory function at rest and the ability to perform maximal exercise but not exercise endurance.

Adult↗
PubMed1990

A comparison of bed rest and immersion for treating the edema of pregnancy.

Bed rest and immersion both lead to a mobilization of extravascular fluid and thus reduce edema. This study compared three treatments for edema in healthy pregnant women in the third trimester: lateral supine bed rest at room temperature, sitting in a bathtub of waist-deep water at 32 +/- 0.5C with legs horizontal, and sitting immersed in shoulder-deep water at 32 +/- 0.5C with legs extended downward. Post-treatment diuresis was selected as the indicator of extravascular fluid mobilization. The mean (+/- SD) diuresis was 105 +/- 48, 161 +/- 155, or 242 +/- 161 mL/hour for bed rest, bathtub, and immersion tank, respectively (P less than .008, tank versus bed rest; P less than .05, tank versus bath). In all treatments, mean arterial pressure (MAP) declined from a baseline value of 88 +/- 9 to 77 +/- 10 mmHg 25 minutes into treatment and 77 +/- 11 mmHg at 50 minutes (both P less than .0001 compared with pre-treatment). Shoulder-deep immersion produced the greatest decline in MAP. Sodium clearance increased from 0.7 to 1.0 mEq/minute in all treatments (P less than .01). Serum sodium, potassium, creatinine, osmolarity, total protein, 6-keto prostaglandin F1 alpha, and plasma volume did not change significantly after the treatments. Serum prolactin declined significantly from 137.8 +/- 44 to 124 +/- 31 ng/mL after treatment; there was no difference among treatments. Immersion appears to be a safe and more rapid method than bed rest to mobilize extravascular fluid during pregnancy.

Adult↗
PubMed1989

Comparison of ventilatory and heart rate responses to hypoxia at rest and during light exercise in high school judo athletes.

Ventilatory and heart rate responses to hypoxia at rest and during light exercise (30W) were compared in 21 high school judo athletes. The results of ventilatory and heart rate responses to hypoxia were analyzed by the hyperbolic equations, VE = VO + AVE/(PETO2-CVE) and HR = HRO + AHR/(PETO2-CHR), respectively, where VE and HR are the observed ventilation and heart rate, VO and HRO the horizontal asymptote in ventilation and heart rate for infinite endtidal PO2 (PETO2), AVE and AHR the slope constants indicating the magnitude of hypoxic sensitivity, and CVE and CHR the vertical asymptote in PETO2 for infinite ventilation and heart rate. AVE was further recalculated after VE was normalized for a 70 kg body mass, using an allometric coefficient, and was defined as AVEN. The absolute magnitudes of hypoxic response in ventilation and heart rate at PETO2 40 mmHg were also determined as delta V40 = AVE/(40-CVE) and delta HR40 = AHR/(40-CHR), respectively. (1) The enhanced hypoxic ventilatory chemosensitivity previously found in heavy-weight judo athletes at rest was confirmed. However this characteristic disappeared with exercise. (2) It was also confirmed that there was no significant correlation between hypoxic heart rate sensitivity and body weight at rest. With exercise, this was found also to be the case. (3) On the other hand, when the hypoxic responses at rest were compared to those of the exercise studies, significant positive correlations were illustrated in both ventilatory and heart rate responsiveness. These results demonstrated that although ventilatory and heart rate responses did not quantitatively exhibit parallel change, the two activities did demonstrate a certain synergism between rest and exercise.

Adolescent↗
PubMed1989

[The influence of increased uterine resting tonus on renal sympathetic nerve activity in pregnant rabbit].

We have shown that an increase in uterine resting tonus causes an increase in maternal blood pressure and a decrease in renal blood flow, and a neural factor may control this phenomenon through a Utero-Renal Reflex in pregnant rabbits. To explore this possible neural factor, we examined the changes in renal sympathetic nerve activity (R-SNA) in late pregnant rabbits under urethane anesthesia. SNA was measured with a bipolar electrode and renal cortical blood flow (RBF) was measured by a thermocouple method. An increase in uterine resting tonus was made by inserting a small balloon into the uterine cavity on the ovarian or cervical side. An increase in resting tonus on the ovarian side caused an increase in maternal blood pressure, increases in R-SNA and renal vascular resistance (RVR), and a decrease in RBF. However, an increase in resting tonus on the cervical side resulted in an increase in maternal blood pressure, slight increases in R-SNA and RVR, and an increase in RBF. These data indicate that an increase in uterine resting tonus can stimulate R-SNA, which in turn causes the deterioration of renal circulation.

Animals↗
PubMed1988

Haemodynamic effects of atenolol and bopindolol at rest and during isometric exercise. A non-invasive study in healthy volunteers.

Circulatory effects of bopindolol, a new nonselective beta blocking agent with intrinsic sympathomimetic activity and atenolol were compared. After baseline and first dose measurements atenolol 25 mg twice daily and bopindolol 1 mg daily were given to 10 healthy young subjects. Haemodynamic measurements were made noninvasively using echocardiography and systolic time intervals. Clinical and circulatory indices were measured at baseline, after initial dose and after one week of regular treatment at rest and at isometric handgrip exercise (IE) (HG). Atenol reduced the heart rate from 62 bpm to 49 and blunted totally the HR increase during IE (p less than 0.01). Bopindolol caused a 10% fall in heart rate (NS) at rest and a 15% fall (p less than 0.05) during IE. BP fell by 6% after atenol administration and 4% after bopindolol (NS) at rest and similarly during IE. In contrast to bopindolol, atenolol caused small increases initially in left ventricular end-diastolic dimension (LVEDD) and left ventricular end-systolic dimension (LVESD). A 10% increase in FS was seen at rest after bopindolol administration (NS). With the fall in heart rate the estimated cardiac output (CO) also fell from 3.66 to 3.151/min (P less than 0.05) after atenolol but rose from 3.87 to 3.93 after bopindolol (NS) during chronic treatment. Consecutively the total peripheral resistance (TPR) was increased to some extent by atenolol, whereas bopindolol reduced it at rest and during IE. A similar response was also found in systolic time intervals PEP/LVET which were reduced during bopindolol administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1978

Influence of resting ECG abnormalities on the ECG response to maximal exercise in women suspected of coronary heart disease.

Coronary arteriographic data have been compared with the ECG response to a maximal exercise test in 53 women with typical or atypical complaints of angina pectoris (AP). All patients with factors known as influencing the repolarization at rest were eliminated and the cases were subdivided according to the presence of a normal (n=26) or abnormal (n=27) resting ECG. The sensitivity (88%) and specificity (81%) of the exertional ECG was not affected by the clinical history nor by the resting ECG data. False positive responses were frequent (32%), particularly among women with atypical AP (50%), but their prevalence was not influenced by the resting ECG data. We conclude that, even in the absence of drug therapy, non-specific resting ECG abnormalities do not influence the ECG response to exercise in women and that they cannot be considered as a factor contributing to the false positive responses: the latter appear to be related to the low prevalence of coronary artery disease in women.

Adult↗
PubMed1988

Comparison of the hemodynamic effects of five calcium channel blockers at rest and during exercise in essential hypertension.

Dihydropyridine and verapamil-like calcium channel blockers reduce blood pressure (BP) in essential hypertension (EH) but have different effects on heart rate (HR) at rest. This study compares the HR and hemodynamic responses to exercise of long-term treatment with nifedipine, nisoldipine, verapamil, tiapamil and diltiazem in five groups of patients with mild and moderate EH (diastolic BP ranging 100-120 mmHg). In a total of 76 patients (mean age 43 years) BP was measured intraarterially, cardiac output by dye dilution (Cardiogreen) and HR by electrocardiogram. Acutely HR and cardiac index (CI) rose (9 and 12%) while BP and total peripheral resistance index (TPRI) were reduced (9 and 19%). After one year calcium channel blockade intraarterial pressure at rest sitting fell from 172/105 to 150/91 mmHg (13%) and at 100 W exercise from 205/109 to 188/97 mmHg (10%). HR remained unchanged in the dihydropyridine groups (range +/- 3%) in all situations while it invariably fell (range 3 to 15%) in the groups treated with verapamil-like calcium blockers. The fall in HR was greater during exercise than at rest (mean 10% vs 6%). With these drugs stroke volume (SV) tended to increase (range 1 to 10%) while it remained unchanged in the dihydropyridine groups. Only minor changes were seen in CO. In all groups the TPRI fell, averaging 15% at rest and during exercise. Thus, the verapamil-like calcium blockers induce a negative chronotropic effect that is enhanced during work, but the cardiac pump function is preserved by a compensatory increase in SI. Independent on the cardiac responses both groups of calcium blockers lower BP by peripheral vasodilatation both at rest and during exercise.

Blood Pressure↗
PubMed1987

[Left ventricular function at rest and during exercise and the effects of propranolol in patients with hypertrophic cardiomyopathy].

To determine left ventricular function during the stress of exercise and to evaluate the effects of propranolol on it in patients with hypertrophic cardiomyopathy (HCM), the ECG-multigated blood pool cardiac scintigraphy was performed in 12 without (HNCM) and 10 with (HOCM) left ventricular outflow obstruction at rest and during bicycle ergometer loading. The results were compared to those in 13 normal subjects. 1. Control measurements: Resting and exercise heart rates and blood pressures did not significantly differ between patients with hypertrophic cardiomyopathy and normal subjects. Ejection fraction (EF) was normal or higher in HCM than in normal subjects at rest, but during exercise it failed to increase normally. The increment in cardiac output was half of the normal value. Responses of count-derived end-diastolic volume (EDV) and stroke volume (SV) were different between HOCM and HNCM. They were unchanged during exercise in HNCM and declined in HOCM. End-systolic volume (ESV) was unchanged in HNCM and slightly decreased in HOCM. Responses of the peak ejection rate (PER) and time to the peak ejection rate (TPE) were not significantly different from normal subjects. Left ventricular (LV) ejection time (ET) and TPE/ET were not different from normal subjects. The peak filling rate (PFR) was significantly higher than normal in HOCM at rest and during exercise. The time to peak filling rate was prolonged at rest in HOCM, but not during exercise. 2. Effects of propranolol: Heart rates significantly decreased especially after intravenous propranolol administration. Cardiac output (CO) and SV were unchanged. EDV and ESV increased significantly. The PER was unchanged. The PFR decreased, but not significantly. TPE, time to the PFR (TPF) and ET were prolonged. The ratio of TPE/ET decreased initially, but abruptly increased later. In conclusion, in the control state of HCM patients, the responses of LVEF, EDV and ESV to exercise were abnormal and CO remained half of the normal. There was no difference between patients with and without obstruction. The effect of propranolol on left ventricular function was more obvious in patients with obstruction than without obstruction, especially in ESV, EDV, PFR and TPF. Propranolol did not improve LV systolic and diastolic functions, but the double product decreased depending on the decrease of heart rate maintaining CO by Frank-Starling mechanism due to increased EDV, which may play a part in improving subjective complaints.

Administration, Oral↗