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Query: UMLS:C0729233 (Thoracic)
 6,478 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anthracyclines are the most frequent cause of iatrogenic congestive heart failure ranging from acute reversible minor, irreversible reduction in the left ventricular ejection fraction and death despite preventive measures. Sensitive methods are needed to detect earliest preclinical cardiotoxicity along with the development of new protective agents. Thirty breast cancer patients were randomly treated with q 21 120 mg/m2 Epirubicin (EPI) x 3, alone (10 patients), or + ICRF-187 (1000 mg/m2) (10 patients) or + C0Q10 (50 mg/day) (10 patients) and monitored by Thoracic Electrical Bioimpedance (TEB) cardiography before (T0) and at the end of chemotherapy (T1), then at 1, 3, 6 months of follow up (F1, F2, F3). a) The group treated with EPI alone showed, between F1-F2, a significant (p < 0.05) decrease in Stroke Index (S1). Acceleration Index (ACI) and a significant (p < 0.05) increase in Systemic Vascular Resistance Index (SVRI), while between F2 and F3 it showed a significant (p < 0.05) recovery in S1 and ACI. b) The group treated with EPI + ICRF-187 showed, between F1 and F2 a significant decrease in S1 and ACI (p < 0.05, p < 0.01 respectively) and a significant (p < 0.05) increase in SVRI: between F2-F3 ACI had a significant (p < 0.05) recovery: c) The group treated with EPI +C0Q10 showed no modification in Sl, ACI, and SVRI during the study. The ejection Fraction (EF) remained unchanged during the study in all the groups. C0Q10 seems to prevent early decreases in cardiac performance and contractiling, thus avoiding an SVRI increase, while ICRF-187 did not. Since ICRF-187 acts by binding iron, we deem that the earliest cardiac involvement, may occur before iron overload; therefore the role of ICRF-187 and C0Q10 in acute or chronic heart toxicity was correlated with high-dose anthracycline and needs to be further investigated.
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PMID:Early detection of the anthracycline-induced cardiotoxicity. A non-invasive haemodynamic study. 906 98

Between January 1, 1992, and January 23, 1996, 111 consecutive patients with severe left ventricular dysfunction underwent isolated coronary artery bypass grafting. The ejection fraction in these patients ranged from 10% to 34% (mean 27.9% +/- 5.4%); in 18 patients the value was less than 20%. The high operative mortality rate (7.6% in Society of Thoracic Surgeons database) in this group of patients at high risk was targeted for reduction by provision of, in addition to the usual inotropic support, progressively more intensive metabolic and mechanical support. The metabolic support consisted of triiodothyronine; glucose, insulin, and potassium; aspartate/glutamate in the cardioplegic solution; and warm-cold-warm/antegrade-retrograde-antegrade cardioplegia. Mechanical support included liberal use of the intraaortic balloon pump, use of a new occlusive retrograde cardioplegia catheter, ultrafiltration to remove myocardial depressant factors, and, finally, delayed sternal closure. The operative mortality rate was 1.8% (2/111). Complications included reoperation because of bleeding (3.6%, 4/111), mediastinitis (1.8%, 2/111), and stroke (0.9%, 1/111) and there were no occurrences of new postoperative acute renal failure (0.0%, 0/111). The intensive care unit stay was 2.2 +/- 0.9 days with a length of stay in the hospital of 13.7 +/- 22.1 days. These techniques done before operation, intraoperatively, and postoperatively optimize the milieu of the depressed left ventricle by maximizing perioperative high-energy phosphate bonds; increasing the effectiveness of inotropic agents; unloading the left ventricle by chemical, metabolic, and mechanical support; and removing known myocardial depressant factors, which reduced the operative mortality rate to 1.8% compared with 7.6% as reported in the Society of Thoracic Surgeons' database.
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PMID:Minimal operative mortality in patients undergoing coronary artery bypass with significant left ventricular dysfunction by maximization of metabolic and mechanical support. 910 74

Thoracic impedance consists of a constant baseline component Z0 and a time-variable component delta Z which represents the impedance change related to the cardiac cycle. The maximum part of delta Z [(dZ/dt)max] represents the peak of the ascending aortic blood flow. Measurements of basal thoracic impedance are affected by structural and anatomical differences in the thorax related to sex and ageing. This component is a variable in the denominator of Sramek's formula which is used for calculating stroke volume. The aim of this study was to elucidate the question as to whether the age- and sex-related variation in basal impedance may affect bioimpedance measurements of stroke volume. The study comprised 111 healthy subjects (55 males and 56 females) of ages between 20 and 69 years, divided according to age decades into five groups each of males and females. Stroke volume index (SI), Z0 and (dZ/dt)max were measured in every subject, using transthoracic bioimpedance cardiography. Z0 and (dZ/dt)max had significantly higher values in females than in males in every age group except the oldest one in the case of Z0 and the oldest two groups in the case of (dZ/dt)max. Stroke index showed no significant sex difference, although the higher Z0 in females may underestimate the values of stroke index. Elevation of (dZ/dt)max in females may therefore reflect a positive relation to Z0 rather than higher flow rates. Since Z0 and (dZ/dt)max are variants in opposite positions in Sramek's formula (denominator and numerator, respectively), this functional relationship may keep the bioimpedance measurements from being affected by the sex- and age-related changes in Z0.
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PMID:Gender and age differences in transthoracic bioimpedance. 936 59

Since the first successful replacement of the aortic arch with perfusion of the head, various methods have been employed to preserve cerebral function during aneurysm operations. Although deep hypothermia was used for surgery of the aortic arch, as early as 1963, the introduction of prolonged circulatory arrest has simplified replacements of the aortic arch. Between October 1990 and September 1993, 69 patients underwent aortic arch replacement for aneurysmal disease at the Dept. of Cardio-Thoracic Surg., University of Vienna. 52 patients had an acute dissection Type A, 17 patients were operated on electively. The patients age (48 male, 21 female) ranged between 16 and 81 years. Primary diagnosis was hypertension (n=44), marfan (n=14), unknown (n=10) and trauma (n=1). Total cardiopulmonary bypass was established via femoral artery cannulation. All patients received Cortison and Thiopental for added cerebral protection. Deep hypothermia (12 degrees C), confirmed by 0-EEG, and circulatory arrest were induced in all patients. The aneurysm was opened longitudinally and a full thickness single patch or "island" of aortic wall, containing the origins of the three arch vessels, was constructed and anastomosed in a continuous fashion to an albumin coated graft. 68 patients survived the operation (intraoperative mortality 1%). The 30-day mortality was 23% (n=16). Twelve patients died of multiorgan failure, two patients of a stroke and two due to myocardial infarction. The mean cerebral circulatory arrest time was 32 minutes (range 11-61 min.). Our experience with aortic arch replacements using profound hypothermia and circulatory arrest supports our contention, that it is the method of choice in this very difficult surgical field.
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PMID:Operative management of aortic arch aneurysm using profound hypothermia and circulatory arrest. 1006 52

Thoracic electrical bioimpedance (TEB) is a harmless, noninvasive, user-friendly technology with wide patient acceptance. Stroke volume (SV) determination is important because it helps to define oxygen transport. Measurement of SV by TEB is rooted in concrete, basic electrical theory, as well as in theoretical models of electrical behavior of the human thorax and great thoracic vessels. This article is concerned with basic electrical theory as applied to TEB, signal acquisition, and the origin of the thoracic cardiogenic impedance pulse (delta Z). The appendix of the chapter features a more extensive overview of alternating current theory as applied to electrical bioimpedance.
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PMID:Electrophysiologic principles and theory of stroke volume determination by thoracic electrical bioimpedance. 1074 8

Hemodialysis (HD) causes rapid volume shifts and circulatory changes. In chronic renal failure (CRF) Na+/K+ATP-ase is depressed, whereas endogenous digoxin-like factor (EDLF) is elevated. Our aim was to characterize HD-induced cardiovascular adaptation and its possible links to Na+/K+ATP-ase and EDLF. Eleven children with CRF on HD (aged 14.7 +/- 3.7 years) and 11 healthy children were investigated for basic circulatory parameters. Thoracic impedance (Zo) and circulatory parameters were monitored by impedance cardiography (ICG) during HD. Erythrocyte Na+/K+ATP-ase and EDLF were measured before and after HD. Up to the loss of 6% of total body weight, Zo rose linearly with fluid removal, above this no further increase occurred. Heart rate and mean arterial pressure (MAP) were inversely related (r = -0.97); MAP rose in the first and decreased in the second part of HD. Systemic vascular resistance paralleled MAP, whereas stroke volume rapidly decreased, but stabilized in the second part of HD. The ratio of preejection period/ventricular ejection time (PEP/VET) correlated positively with HD duration (r = 0.92), suggesting diminished cardiac filling. Cardiac index (CI) remained stable. EDLF was high in uremia accompanied by depressed Na+/K+ATP-ase (P < 0.05 and P < 0.01, respectively). Following HD Na+/K+ATP-ase normalized. Correlation between Na+/K+ATP-ase activity and MAP was linear (r = 0.85). In conclusion, ICG during HD provides detailed information concerning circulatory adaptation resulting in stable CI, suggesting that the dialysis-induced hypovolemia is compensated by the centralization of the blood volume. Changes of Na+/K+ATP-ase indicate that dialyzable blood pressure-regulating substance(s) inhibit(s) the pump. However, lack of further correlation between Na+/K+ATP-ase, EDLF, and cardiovascular parameters indicates the complexity of the regulatory processes.
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PMID:Monitoring cardiovascular changes during hemodialysis in children. 1119 97

To facilitate international multicentre studies and quality control of infant pulmonary function measurements, the European Respiratory Society-American Thoracic Society (ERS-ATS) working group for infant lung function testing aims to develop specifications for standardized infant lung function equipment and software. However, a standardized test device is also needed to test whether existing infant lung function equipment is able to meet these requirements. The authors have built a "mechanical model baby" consisting of a linear pump which can reproduce prerecorded tidal flow waveforms with a precision of 0.5% (full stroke), enabling the simulation of tidal and forced flow patterns. This linear pump can be connected to a series of copper lung volumes (range 50-300 mL) with known time constants, so that lung volumes can be reproduced with a precision of +/-1% at frequencies 10-120bpm. Five airflow resistors were built using sinter material. When assessed using flows 0-300 mL.s(-1) all resistors showed a quasilinear pressure/ flow relationship, with slopes 1.0-5.6 kPa.L(-1).s. These resistances could be reproduced with a precision of +/-2.5%. The infant lung model can also be used to assess frequency responses of infant lung function equipment, since the pump is capable of delivering low amplitude volumes up to 20 Hz in a pseudorandom noise manner. In summary, based on error estimations, this infant lung model is able to test whether or not infant lung function equipment meets the requirements suggested by the European Respiratory Society-American Thoracic Society standardization group, that is: flow measurements within +/-2.5%, volume and resistance measurements within +/-5%, frequency response: magnitude attenuation <+/-10% and phase shift <+/-3 degrees at 10 Hz.
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PMID:The infant lung function model: a mechanical analogue to test infant lung function equipment. 1140 Oct 74

Off-pump coronary artery bypass technique or bypass graft surgery without the use of a heart-lung machine has been introduced in the last six years, and now comprises approximately 25 per cent of all coronary artery bypass surgery being done in the world. One of the goals of beating heart surgery is to eliminate the complications associated with the use of cardiopulmonary bypass. The use of all arterial conduits for coronary artery bypass graft has become more acceptable after experiences gained and reports of better long-term results. From January 2001 to December 21 2002 the authors performed 251 off-pump procedures. One hundred and nine of these cases were done utilizing all arterial conduits. The data was stratified using the US National Society of Thoracic Surgeons Cardiac Surgery Database pre-operative risk module and divided into 3 groups as suggested: Low risk group with a predicted mortality of 0-1 per cent (2 patients); Medium risk group with a predicted mortality of 2-9 per cent (87 patients), and High risk group with a predicted mortality of 10+ per cent (10 patients). The predicted mortality of the entire group was 4.5 per cent. There were 90 males and 19 females with a mean age of 60.2 +/- 10.7 years, with 15.6 per cent of them older than 70 years. Pre-operative co-morbidities included 1/4 of the patients who had ejection fraction (EF) of equal to or less than 0.4, 4.5 per cent had unstable angina, 1.6 per cent had urgent/emergent status, 26.6 per cent underwent re-operative procedure, 1 per cent had pre-operative serum creatinine more than 2 mg per cent, 4.8 per cent had a history of stroke, 20.2 per cent had a history of congestive heart failure, 45.2 per cent had a history of previous myocardial infarction, 10.7 per cent had a history of chronic obstructive pulmonary disease, 46.9 per cent had a history of diabetes, 62 per cent had hypertension, and 20 patients (18.3%) required intra aortic balloon pump. Intra-operative parameters revealed 3.7 +/- 1.3 grafts/patient. The left internal mammary artery (LIMA) was used to the left anterior descending (LAD) in 6.4 per cent, or sequential with the diagonals 93.6 per cent. The 30 days mortality was 3.6 per cent (4 cases). Further analysis revealed that pre-operatively, none of these 4 cases was in the low predicted (predicted mortality of 0-1%) risk group, 2 of them were in the medium (predicted mortality of 2-9%) and the other 2 were in the high predicted risk (predicted mortality of 10+%) group. The skin-to-skin time was 4.1 hours and there were two conversions to on-pump in this group. Post-operatively, the intubation time was 4.7 hours. There was no peri-operative myocardial infarction, one patient required dialysis, and no patient experienced stroke. There was no sternal wound or arm wound infection, 9.5 per cent experienced temporal sensation impairment at the site of the radial artery harvesting at one month. Re-operation for bleeding occurred in 3 cases, and thirteen patients (14.3%) developed new atrial fibrillation. The authors are no longer making a one-foot long incision and spread ten inches wide like in the old days'. With the less invasive approach lessened in the recent past, the authors have found the less invasive the incision the less the pain after surgery. Totally eliminating the leg incision has allowed the patient to get up and mobilize on the same afternoon, if the procedure was done in the morning. All of these approaches combined with the off-pump technique, as far as the authors are concerned, will provide those who need coronary arterial bypass graft the best operative procedure.
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PMID:Off-pump coronary bypass surgery and all arterial conduits: learning experience at Bangkok Heart Institute. 1286 64

The purpose of this study was to evaluate the overall outcome of repair of thoracic aortic lesions with endoluminal grafts. Patients were studied prospectively following the implantation of a thoracic endovascular device. Preoperative imaging was performed by helical computed tomography (CT), angiography, transesophageal ultrasonography, or magnetic resonance imaging. Procedures were performed in an endovascular surgical suite under general anesthesia. All patients were evaluated with CT and chest radiography at discharge and at 1, 6, and 12 months. From December 1999 to November 2001, thirty-two patients were enrolled in the study (mean age 62 years; 20 male and 12 female patients). Seventeen patients had dissections, five patients had ruptured aortic ulcer, five patients had traumatic ruptures, three patients had atherosclerotic aneurysms, and two patients had pseudoaneurysms. An American Society of Anesthesiology score of III or IV was evaluated in 22 (69%) patients. The procedure was performed under emergency conditions in 11 cases. All prostheses were implanted successfully. There were no conversions. Three patients (9%) presented with a neurologic event following the implantation procedure, which was lethal in one case (hemorrhagic stroke). Two other patients died during early follow-up of myocardial infarction and multiorgan failure. The early death rate was 9%. The mean follow-up was 13.5 months. During follow-up, the maximal diameter of the aorta shrunk (> or = 5 mm) in 9 (28%) patients, remained stable in 17 (53%) patients, and increased (> or = 5 mm) in 6 (19%) patients. All patients presenting with an increased diameter were initially treated for dissections. A type 1 endoleak was diagnosed on the discharge CT scan in one patient. It sealed spontaneously thereafter. A type 3 endoleak was diagnosed 3 months after the procedure in one patient. A complementary stent graft was implanted in two patients presenting with a dissection with persistent patent false lumen and aortic enlargement. Three patients died during follow-up (two aneurysm-related and one aneurysm-unrelated death). The morbidity and mortality rates reported in our series related to the preoperative morbid conditions of the patients treated. Thoracic aorta endografting is an alternative to open surgery in this subset of patients.
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PMID:Midterm results of endoluminal stent grafting of the thoracic aorta. 1558 26

The purpose of this study was to examine whether the heart rate (HR) deflection point (HRDP) in the HR-power relationship is concomitant with the maximal stroke volume (SV(max)) value achievement in endurance-trained subjects. Twenty-two international male cyclists (30.3 +/- 7.3 yr, 179.7 +/- 7.2 cm, 71.3 +/- 5.5 kg) undertook a graded cycling exercise (50 W every 3 min) in the upright position. Thoracic impedance was used to measure continuously the HR and stroke volume (SV) values. The HRDP was estimated by the third-order curvilinear regression method. As a result, 72.7% of the subjects (HRDP group, n = 16) presented a break point in their HR-work rate curve at 89.9 +/- 2.8% of their maximal HR value. The SV value increased until 78.0 +/- 9.3% of the power associated with maximal O(2) uptake (Vo(2 max)) in the HRDP group, whereas it increased until 94.4 +/- 8.6% of the power associated with Vo(2 max) in six other subjects (no-HRDP group, P = 0.004). Neither SV(max) (ml/beat or ml.beat(-1).m(-2)) nor Vo(2 max) (ml/min or ml.kg(-1).min(-1)) were different between both groups. However, SV significantly decreased before exhaustion in the HRDP group (153 +/- 44 vs. 144 +/- 40 ml/beat, P = 0.005). In the HRDP group, 62% of the variance in the power associated with the SV(max) could also be predicted by the power output at which HRDP appeared. In conclusion, in well-trained subjects, the power associated with the SV(max)-HRDP relationship supposed that the HR deflection coincided with the optimal cardiac work for which SV(max) was attained.
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PMID:Heart rate deflection point as a strategy to defend stroke volume during incremental exercise. 1561 21


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