[Restoration of cardiac function following its arrest induced by potassium iodide after stimulation of the vagus nerve].
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Cardiovascular Physiological Phenomena↗
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[Hemodynamic analysis of cardiac function in patients with acute myocardial infarction].
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Adult↗
Effects of exercise training on myocardial fatty acid metabolism in rats with depressed cardiac function induced by transient ischemia.
The effects of exercise training on metabolic and functional recovery after myocardial transient ischemia were investigated in a rat model. Male Wistar Kyoto rats were subjected either to a 30-min left coronary artery occlusion followed by reperfusion or to a sham operation. At 4 weeks after operation, the rats were randomly assigned either to sedentary conditions or to exercise training for 6 weeks. In the ischemic rats, pinhole SPECT (single photon emission computed tomography) imaging with thallium-201 (201Tl) and 123I-(rho-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) showed a reduction of both myocardial perfusion and fatty acid metabolism in the risk zone of the left ventricle (LV). The LV was dilated and the ejection fraction was decreased after ischemic injury. The severity score showed a significant decrease on both 201Tl and BMIPP (201Tl, from 19.9+/-2.7 to 17.0+/-2.2, p<0.05; BMIPP, from 21.5+/-2.4 to 18.6+/-1.9, p<0.05) after exercise training in the ischemic trained rats, but did not change significantly in their sedentary counterparts. Plasma levels of free fatty acids normalized in the ischemic trained rats, but elevated in the ischemic sedentary rats (0.53+/-0.05 vs 0.73+/-0.06 mmol/L, p<0.05). Furthermore, the trained rats had a significant increase in LV stroke volume (0.25+/-0.02 vs 0.21+/-0.01 ml/beat, p<0.05) and adaptive cardiac hypertrophy. These findings demonstrate that adaptive improvements in myocardial perfusion, fatty-acid metabolism and LV function were induced by exercise training after transient ischemia.
Animals↗
Sex differences in cardiac function of a group of young adults.
Ballistocardiogram and carotid pulse recordings were made on a group of healthy young men and women aged 25--35 years. The recordings were subjected to a newly developed procedure for feature recognition and measurement (FRAM) by digital computer. Results from the FRAM were grouped according to sex of subjects tested and inspected for statistically significant differences in mean values of the many separate items calculated. There were marked differences between the men and women in those items most closely related to initial acceleration of blood in the aorta. It was hypothesized that the hyperdynamic values from the males were indicative of intrinsic functional differences between their myocardia and that of the females.
Adult↗
[Systolic time intervals by intratracheal pneumocardiogram and the effects of inhalation anesthetics on cardiac function using this technic].
Intratracheal pressure change due to cardiogenic oscillation was obtained by a high gain pressure transducer attached to the endotracheal tube while the patient was apneic during the operation. Such pressure change has been called as intratracheal pneumocardiogram (ITCG), which consists of wide waves and some spikes. Systolic time interval (STI) was obtained by measuring the intervals between certain spikes. The STIs measured by ITCG were compared with those by echocardiogram and by the conventional method. Also the effects of halothane, enflurane and isoflurane on cardiac performance were evaluated using the STI by ITCG. The STI measured by ITCG correlated well with that by echocardiogram, which indicated that the STI by ITCG was a useful noninvasive method to monitor the cardiac performance during general anesthesia. The STI by ITCG showed that the left ventricular ejection time (LVET) decreased in halothane and enflurane anesthesia. The pre-ejection period (PEP) and the PEP/LVET ratio increased in all three types of anesthesia. Especially the PEPs during halothane and enflurane at 1.8 MAC (minimum alveolar concentration) were greater than that of isoflurane. The results suggest that isoflurane has less cardiac depressive action than halothane and enflurane.
Adult↗
Magnetic resonance imaging of cardiac function and morphology in patients with transposition of the great arteries following Mustard procedure.
In order to assess the diagnostic possibilities of magnetic resonance imaging (MRI), 30 children (mean age 11.5 years) with d-transposition of the great arteries (TGA) corrected by the Mustard procedure were studied. Patient values were compared to those of 10 healthy volunteers. The most important postoperative abnormalities such as baffle leaks, systemic or pulmonary venous obstructions, left ventricular outflow tract (LVOT) stenosis and tricuspid regurgitation were assessed. Cardiac volumes and muscle mass were measured. Baffle leaks were found in 5 and obstruction of the baffle limbs in 6 patients. On gradient echo images 13 patients showed signs of LVOT stenosis and 12 tricuspid incompetence. Right ventricular end diastolic volumes in patients were significantly higher than the left ventricular volumes, but slightly lower than right ventricular volumes in the normals. In patients with TGA and ventricular septal defect (VSD) (n = 7) right ventricular (RV) volumes were found to be higher than in patients with intact ventricular septum (n = 23) and in normals. In contrast to the normal RV function of patients after Mustard surgery only patients with previous VSD showed a diminished RV ejection fraction. The muscular mass in TGA patients showed a ratio of 1.9:1 between right and left ventricles. In normals the ratio was 1:1.5. Magnetic resonance imaging allows a quantitative insight into the ventricular function and the morphology of the heart after inflow correction. Thus, it supplements the noninvasive evaluation of TGA patients.
Adolescent↗
Effects of ACE inhibition and angiotensin II type 1 receptor blockade on cardiac function and G proteins in rats with chronic heart failure.
1. Inhibition of the renin-angiotensin system (RAS) improves symptoms and prognosis in heart failure. The experimental basis for these benefits remains unclear. We examined the effects of inhibition of ACE or blockade of angiotensin II type 1 (AT1) receptor on the haemodynamics, cardiac G-proteins, and collagen synthesis of rats with coronary artery ligation (CAL), a model in which chronic heart failure (CHF) is induced. 2. Rats were orally treated with the ACE inhibitor trandolapril (3 mg kg(-1) day(-1)) or the AT1 receptor blocker L-158809 (1 mg kg(-1) day(-1)) from the 2nd to 8th week after CAL. CAL resulted in decreases in the left ventricular systolic pressure and its positive and negative dP/dt, an increase in the left ventricular end-diastolic pressure, and the rightward shift of the left ventricular pressure-volume curve. Long-term treatment with either drug improved these signs of CHF to a similar degree. 3. Cardiac Gsalpha and Gqalpha protein levels decreased, whereas the level of Gialpha protein increased in the animals with CHF. Long-term treatment with trandolapril or L-158809 attenuated the increase in the level of cardiac Gialpha protein of the animals with CHF without affecting Gsalpha and Gqalpha protein levels. Cardiac collagen content of the failing heart increased, whose increase was blocked by treatment with either drug. 4. Exogenous angiotensin I stimulated collagen synthesis in cultured cardiac fibroblasts, whose stimulation was attenuated by either drug. 5. These results suggest that blockade of the RAS, at either the receptor level or the synthetic enzyme level, may attenuate the cardiac fibrosis that occurs after CAL and thus affect the remodelling of the failing heart.
Angiotensin I↗
Circulatory shock following intravenous propoxyphene poisoning. An experimental study of cardiac function and metabolism in pentobarbital-anesthetized pigs.
The effects of continuously administered intravenous propoxyphene chloride (15 mg X min-1) on ECG, systemic, pulmonary and coronary circulations and myocardial oxygenation were investigated in eight pentobarbital-anesthetized pigs. Circulatory shock, defined as a systolic blood pressure below 60 mmHg (8.0 kPa) and a cardiac output of approximately 2.0 l X min-1 X m-2, occurred after 675 to 2025 mg propoxyphene chloride. At the time when shock occurred plasma concentrations of propoxyphene ranged from 9.6 to 15.3 micrograms X ml-1 which is within the range of the lethal concentration observed in man. Statistically significant decreases were observed for the following variables: maximum rate of rise of left ventricular pressure dP/dt (-90%), mean arterial pressure (-73%), heart rate (-46%), cardiac index (-58%), stroke volume index (-22%), left ventricular stroke work index (-85%), right ventricular stroke work index (-63%) and systemic vascular resistance (-50%). Mean pulmonary arteriolar occlusion pressure increased (+42%), whereas mean right atrial pressure and pulmonary vascular resistance remained unchanged. The arteriovenous oxygen difference increased (+53%) and total body oxygen consumption decreased (-35%). The following coronary variables decreased: coronary sinus blood flow (-57%), coronary vascular resistance (-65%), myocardial oxygen consumption (-68%), myocardial oxygen extraction (-26%) and myocardial lactate extraction (-28%). Prolongation of the ECG PQ and QRS intervals were recorded shortly before shock appeared, and all animals were in sinus rhythm till the last minute before death. The results indicate that intravenously administered propoxyphene besides being a powerful negative inotropic and chronotropic agent, is also a potent systemic and coronary vasodilator.
Anesthesia, General↗
["Functional cardiac symptoms"].
1. Symptoms which may afflict us include a characteristic chest pain, a typical palpitation, a special kind of breathlessness and a peculiar loss of consciousness. These symptoms differ from the symptoms produced by heart diseases. They are psychic in origin and the manifestation of a special state of mind. The misleading term "functional symptoms" should be abandoned. 2. The psychogenic symptoms are very frequent. 170 out of a non-selected group of 310 patients in a cardiological private practice complained of one or the other of these symptoms. In 107 of these patients the complaints were exclusively psychic in origin. More than half of all chest pains, 30% of all palpitations, a fourth of the breathlessness and 65% of all loss of consciousness belonged to this category. 3. Awareness that these symptoms are harmless, and that complete well-being is a rather rare and mostly shortlived gift, would appear to be helpful and is often followed by a considerable improvement in health. In other patients, however, more extensive psychotherapy appears to be needed.
Dyspnea↗
Measurement of cardiac function in conscious rats.
The goal of this study was to establish that 1. blood velocity profile in the rat aorta is parabolic, and 2. measure of left ventricular thickening fraction can be used in rats. Spontaneously hypertensive and normotensive Wistar Kyoto rats were instrumented with a 20-MHz pulsed Doppler flow probe around the thoracic aorta and a 20-MHz pulsed Doppler thickening probe on the left ventricle. Doppler frequency shifts were measured throughout the entire aorta diameter, and individual blood velocity profiles were constructed. It was demonstrated that blood velocity in the ascending aorta of rats is laminar; therefore, cardiac output can be measured using the pulsed Doppler method. In Wistar Kyoto rats, left ventricular thickening fraction was 24 +/- 1% and 25 +/- 1%, 2 and 3 weeks following surgery. In spontaneously hypertensive rats, left ventricular thickening fraction was 22 +/- 2%. Halothane depressed left ventricular thickening fraction, whereas isoproterenol increased left ventricular thickening fraction in conscious rats. Thus, pulsed Doppler technique is a valuable tool for evaluating cardiovascular function in conscious rats.
Analysis of Variance↗
[Complex ultrasonic examination in the diagnosis and evaluation of cardiac function in right-ventricular infarction].
Combined ultrasound investigation (two-dimensional, contrast, Doppler, Mechocardiography) was performed in 32 patients with acute myocardial infarction (AMI). Echo- and electrocardiographic evidence and clinical symptoms suggested AMI of both ventricles in 22 patients. Ten patients with AMI in the left ventricle only made up the control sample. Right cardiac compartments were probed to verify right-ventricular insufficiency. Right-ventricular involvement was confirmed by autopsy in 6 patients. Clinical signs of right-ventricular AMI were detected in 63.6% of second-group patients, and electrocardiographic signs of the same, in 54.6%. Asynergic areas were detected in right-ventricular wall of 90.5% of patients. In cases of right-ventricular AMI, right compartment section area was increased significantly, while right-ventricular evacuation fraction was as significantly reduced. Doppler echocardiography demonstrated a low right-ventricular rapid filling peak rate, as compared to the respective slow filling rate, an indirect indication of right-ventricular AMI. Combined ultrasound investigation is therefore an effective tool for the diagnosis of right-ventricular AMI and assessment of heart performance.
Adult↗
[Effects of various forms of myocardial protection on cardiac function, metabolism, and blood flow (author's transl)].
The myocardial protective effect of two cardioplegic solutions was studied after an ischemic period of 2 h in eight dogs. Group I received a high potassium solution (St. Thomas Hospital) and group II a sodium withdrawal solution with high colloid osmotic pressure (Eppendorf solution). With the exception of a prolonged myocardial K+ washout (10 min) in group I, which was presumably responsible for fibrillation in the early reperfusion period, no major metabolic or perfusion differences between the two groups were observed. After 30 min of reperfusion, postischemic LV function (-43%) and O2 uptake (-43%) were equally reduced in both groups.
Animals↗
Effects of single doses of radiation on cardiac function in the rat.
The hearts of rats were irradiated locally to single doses of X-ray in the range of 20-50 Gy. The mean latency period between treatment and death ranged from 550 +/- 12 days to 260 +/- 13 days for animals irradiated with doses of 20 and 50 Gy. The growth rate and cardiac output was followed for a period of 10 months after treatment. In irradiated animals, there was a delay in growth and the rate of growth plateaued at approximately 6 months after treatment. Cardiac output was measured by an external counting technique. There was a general decline in cardiac output at time intervals from 4 to 10 months after irradiation. This reduction in cardiac output was dose-dependent. A single dose of 30 Gy reduced the cardiac output to approximately 70% of the control value, 6 months after irradiation.
Animals↗
A prospective randomized trial of preoperative "optimization" of cardiac function in patients undergoing elective peripheral vascular surgery.
BACKGROUND: Previous investigations have suggested that preoperative invasive hemodynamic monitoring with "optimization" of cardiovascular function may favorably affect the outcome among patients undergoing peripheral vascular surgery. The purpose of this study was to evaluate the effect of preoperative optimization of hemodynamic parameters on outcome in patients undergoing aortic reconstruction (AR) or limb salvage procedures (LSP) in a randomized, prospective clinical trial. METHODS: All 72 patients who consented to participate in this study were admitted to the intensive care unit at least 12 hours before operation for placement of a pulmonary artery catheter (PAC). Patients who were randomized to the treatment group (n = 32) were "optimized" by adjusting their hemoglobin concentration, oxygen saturation (SaO2), cardiac output, or afterload until the mixed venous O2 saturation (SvO2) was at least 65%. The control group (n = 40) underwent placement of a PAC and had oxygen transport parameters measured without any attempt to optimize SvO2. RESULTS: There were no significant differences between the treatment and control groups with respect to age, gender, type of operation, initial Acute Physiology and Chronic Health Evaluation (APACHE) II score, SvO2, pulmonary artery occlusion pressure, or cardiac index. All treatment patients achieved an SvO2 of at least 65% before operation. Comparing the treatment and control groups, postoperative cardiovascular complications occurred in 25% versus 27%, intraoperative complications in 28% versus 20%, and death in 9% versus 5%, respectively. None of these differences was statistically significant as a whole or within the subgroups undergoing AR or LSP. CONCLUSIONS: These data suggest that preoperative optimization of cardiovascular function by using achievement of SvO2 above 65% as the end point does not result in any reduction of intraoperative or perioperative cardiac complications in patients undergoing PVS. Further studies with alternative assessments and manipulation of different cardiopulmonary parameters may yield additional information.
Aged↗
Effect of dobutamine on cardiac function in man: reciprocal roles of heart rate and ventricular stroke volume.
The cardiovascular effects of dobutamine ( 7 micrograms/kg . min iv) and of additional N-allyl-clonidine (St 567, alinidine; 0.3 mg/kg iv), a compound which selectively inhibits the chronotropic effects of various stimulants, were studied in 9 patients scheduled for major abdominal surgery. Dobutamine increased cardiac index (CI), mean arterial pressure (MAP), mean pulmonary artery pressure (MPAP), and heart rate, but failed to change the left ventricular stroke volume (LVSV) significantly. Alinidine decreased cardiac rate and increased LVSV index and left ventricular stroke work index (LVSWI), whereas CI, MAP, and MPAP remained virtually unaffected. Similar results were obtained when the combination of dobutamine and alinidine was given to 4 patients in neuroleptanesthesia. Thus, the decrease in preload which is associated wit tachycardia seems to modify the increase in LVSV in response to inotropic stimulation with dobutamine.
Adult↗
Adrenergic responsiveness is reduced, while baseline cardiac function is preserved in old adult conscious monkeys.
To examine the physiological deficit to adrenergic stimulation with aging, five younger adult (3 +/- 1 yr old) and nine older adult (17 +/- 1 yr old) healthy monkeys were studied after instrumentation with a left ventricular (LV) pressure gauge, aortic and left atrial catheters, and aortic flow probes to measure cardiac output directly. There were no significant changes in baseline hemodynamics in conscious older monkeys. For example, an index of contractility, the first derivative of LV pressure (LV dP/dt) was similar (3,191 +/- 240, young vs. 3,225 +/- 71 mmHg/s, old) as well as in isovolumic relaxation, tau (24.3 +/- 1.7 ms, young vs. 23.0 +/- 1.0 ms, old) was similar. However, inotropic, lusitropic, and chronotropic responses to isoproterenol (Iso; 0.1 micrograms/kg), norepinephrine (NE; 0.4 micrograms/kg), and forskolin (For; 75 nmol/kg) were significantly (P < 0.05) depressed in older monkeys. For example. Iso increased LV dP/dt by by 146 +/- 14% in younger monkeys and by only 70 +/- 5% in older monkeys. Iso also reduced tau more in younger monkeys (-28 +/- 7%) compared with older monkeys (-13 +/- 3%). Furthermore, peripheral vascular responsiveness to Iso, NE, For, and phenylephrine (PE; 5 micrograms/kg) was significantly (P < 0.05) reduced in older monkeys. For example, phenylephrine (5 micrograms/kg) increased total peripheral resistence by 69 +/- 4% in younger monkeys and by only 45 +/- 3% in older monkeys. Thus in older monkeys without associated cardiovascular disease, baseline hemodynamics are preserved, but adrenergic receptor responsiveness is reduced systemically, not just in the heart.
Adrenergic Agents↗
Heterozygous cellular glutathione peroxidase deficiency in the mouse: abnormalities in vascular and cardiac function and structure.
BACKGROUND: Oxidant stress has been implicated in the pathogenesis of atherothrombosis and other vascular disorders accompanied by endothelial dysfunction. Glutathione peroxidases (GPx) play an important role in the cellular defense against oxidant stress by utilizing glutathione (GSH) to reduce lipid hydroperoxides and hydrogen peroxide to their corresponding alcohols. Cellular GPx (GPx-1) is the principal intracellular isoform of GPx. We hypothesized that GPx-1 deficiency per se induces endothelial dysfunction and structural vascular abnormalities through increased oxidant stress. METHODS AND RESULTS: A murine model of heterozygous deficiency of GPx-1 (GPx(+/-)) was investigated to examine this hypothesis. Mesenteric arterioles in GPx-1(+/-) mice demonstrated vasoconstriction to acetylcholine compared with vasodilation in wild-type mice (maximal change in vessel diameter, -13.0+/-2.8% versus 13.2+/-2.8%, P<0.0001). We also noted an increase in the plasma and aortic levels of the isoprostane iPF(2alpha)-III, a marker of oxidant stress, in GPx-1(+/-) mice compared with wild-type mice (170.4+/-23 pg/mL plasma versus 98.7+/-7.1 pg/mL plasma, P<0.03; 11.7+/-0.87 pg/mg aortic tissue versus 8.2+/-0.55 pg/mg aortic tissue, P<0.01). Histological sections from the coronary vasculature of GPx-1(+/-) mice show increased perivascular matrix deposition, an increase in the number of adventitial fibroblasts, and intimal thickening. These structural abnormalities in the myocardial vasculature were accompanied by diastolic dysfunction after ischemia-reperfusion. CONCLUSIONS: These findings demonstrate that heterozygous deficiency of GPx-1 leads to endothelial dysfunction, possibly associated with increased oxidant stress, and to significant structural vascular and cardiac abnormalities. These data illustrate the importance of this key antioxidant enzyme in functional and structural responses of the mammalian cardiovascular system.
Animals↗
A modified myocardial performance (Tei) index based on the use of valve clicks improves reproducibility of fetal left cardiac function assessment.
OBJECTIVE: To determine whether a modified myocardial performance index (Mod-MPI) involving assessment of the movements (clicks) of the mitral valve (MV) and aortic valve (AV), improves intra- and interobserver agreement as compared to the previously reported method for MPI estimation. METHODS: The Mod-MPI was recorded by two experienced operators in the left cardiac chambers of 25 normally grown fetuses using pulsed Doppler ultrasonography. The isovolumetric contraction time (ICT) was measured from the closure of the MV to the opening of the AV, the ejection time (ET) from the opening to the closure of the AV, and the isovolumetric relaxation time (IRT) from the closure of the AV to the opening of the MV. The Mod-MPI was calculated as (ICT + IRT)/ET. In addition, the MPI was estimated without using the valve clicks (F-MPI) as previously described. Intra- and interobserver agreement were then analyzed for both modalities. RESULTS: There was a significantly lower intra- and inter-observer variability in the estimation of all time periods with the Mod-MPI than with the F-MPI (ICT: intra-observer, 9.9% vs. 13.9%; interobserver 9.9% vs. 15.6%; IRT: intraobserver, 9.9% vs. 14.8%; interobserver 10.4% vs. 18.3%; and ET: intraobserver, 4.5% vs. 6.1%; interobserver 2.8% vs. 5.2%, respectively). Intraclass correlation coefficient (IntraCC) for the Mod-MPI was 0.8 (95% confidence interval (95% CI), 0.56-0.9) and for the F-MPI, the IntraCC was 0.62 (95% CI, 0.26-0.84); P = 0.01. Agreement between observers using the Mod-MPI showed a mean difference of 0.0 with 95% limits of agreement (LA) -0.09 (95% CI, -0.1 to -0.075) to 0.09 (95% CI, 0.075-0.1) and for the F-MPI the mean difference was -0.01 with 95% LA -0.26 (95% CI, -0.3 to -0.22) to 0.25 (95% CI, 0.21-0.29). CONCLUSION: Calculation of the Mod-MPI based on Doppler echoes of the MV and AV clicks is associated with a lower variation and better inter- and intraobserver agreement than the previously used method for fetal cardiac evaluation.
Aortic Valve↗