Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cardiac Conditions”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources
PubMedDate not supplied

The "response" in behavior theory.

The term "response" is a basic one in behavior theory, particularly reflex theory, but its definition is not clear. The origin of the term in the common vocabulary has affected its later extensions in the analysis of behavior. Some contemporary theorists accept the existence of two "types" of response, coordinating one with the Pavlovian conditioning procedure, the other with the operant conditioning procedure of the so-called "contingent" variety. Reservations are expressed here about such distinctions between response classes and conditioning paradigms, emphasizing the difficulties that arise from certain conventions and inadequacies in current definitions and conceptions of "response". The critical nature of the problem for behavior theory is illustrated once again by the recent laboratory finding that a familiar and accepted conditional reflex, that of the "conditioned cardiac CR," can be fractionated into "parts" and is therefore perhaps no longer to be treated as a single unitary "response".

Animals↗
PubMed1975

Cardiac performance during pregnancy: serial evaluation using external systolic time intervals.

Indirect systolic time indices were used to evaluate serial changes in left ventricular function during pregnancy in 13 normal patients and five patients with compensated cardiac conditions. Changes in both groups tended to parallel each other. In both groups, serial LVET index decreased, PEP index increased, and PEP/LVET ratio increased. Q-S2 index decreased in the normal group in midpregnancy and was inconsistent in the cardiac group. In the immediate postpartum period, LVET index returned to baseline values but PEP and PEP/LVET remained increased in both groups. Results of multiple comparison tests demonstrated that the largest (or smallest) value of each systolic time interval during pregnancy was observed in either the periods of the weeks 28 to 34 or 34 to 38. No significant differences were noted in intergroup comparison between the normal and cardiac groups. These data suggest that consistent changes in cardiac function may be determined during pregnancy by the noninvasive technique of indirect systolic time interval evaluation. These changes may reflect a change in left ventricular contractility, preload or afterload. The differences may persist even in the immediate postpartum period when cardiac output and heart rate have decreased to normal, suggesting residual changes in intrinsic left ventricular function. In patients with compensated heart disease, indirect tests of left ventricular function generally reflect the changes in normal pregnant women.

Adolescent↗
PubMed2004

Sudden cardiac death in the young in Sweden: electrocardiogram in relation to forensic diagnosis.

OBJECTIVES: To study electrocardiogram (ECG) in relation to forensic diagnosis in young persons who suffered a sudden cardiac death (SCD) in Sweden during 1992-99. DESIGN: A register study of a national database of forensic medicine in Sweden, selecting all cases of SCD 15-35 years of age. In this group, 12-lead ECGs and clinical data were searched for in military conscription and medical records. The ECGs were re-analysed and classified according to the Minnesota code criteria. SETTING: The whole nation of Sweden. SUBJECTS: Sudden cardiac death victims (66 individuals), 15-35 years of age, where it was possible to obtain an ECG recording. RESULTS: We observed major or minor ECG abnormalities in 82% of the subjects. The most common changes were T wave abnormalities (35%), ST segment changes (32%) and conduction defects (20%). The ECGs were evaluated as pathological in 50% of the cases, more often in arrhythmogenic right ventricular cardiomyopathy (88%) and hypertrophic cardiomyopathy (82%). Cardiac-related symptoms were seen in 76% of the total group and there was a family history of a similar cardiac condition in 18%. CONCLUSIONS: Pathological ECGs were common in young SCD victims, in spite of being taken many years before death. An ECG could help identify prospective victims of SCD, and should always be taken in cases with possible cardiac-related symptoms or a family history of SCD. The pathological ECGs were often found in connection with routine screening at military enlistment for men, which raises the question of a routine screening in the young, including women.

Adolescent↗
PubMed1978

Locus of control and cardiac response to reaction time, mental arithmetic, and time-estimation tasks.

In Exp. 1 subjects, classified on the basis of locus of control scores, performed both reaction time and mental arithmetic tasks. In Exp. 2, similarly classified subjects were required to estimate the duration of a signal with feedback following each trial. Between-groups comparisons in Exp. 1 showed no differences on heart rate or performance measures. This does not support an explanation of differential heart rates during cardiac conditioning based upon cognitive styles of "rejecting" or "accepting" stimuli. Similar comparisons in Exp. 2 indicated significant differences for heart rate and proficiency in time estimation. These differences suggest greater task involvement for internally controlled subjects on feedback tasks, with cardiac acceleration a function of that involvement.

Attention↗
PubMed2007

Determinants of endurance exercise capacity in the heat in prepubertal boys.

The goal of this study was to identify factors which limit exercise endurance in hot ambient conditions in prepubertal boys. Eight healthy non-acclimatized, highly physically active prepubertal boys performed steady load cycling at approximately 65 % peak VO (2) to exhaustion in both cool (19.6 +/- 0.6 degrees C, 66.4 +/- 11.0 % relative humidity) and hot (31.0 +/- 0.3 degrees C, 56.9 +/- 2.0 % relative humidity) environmental conditions. Cardiac output, oxygen uptake, rectal temperature (T (re)), rating of perceived exertion (RPE), blood pressure, and calculated arterial venous oxygen difference were obtained serially in each testing session, and percent dehydration was calculated from body weight loss. Endurance time was significantly shorter in the hot condition (29.30 +/- 6.19 minutes versus 41.38 +/- 6.30 minutes in the cool room). No significant differences in circulatory markers or hydration status were observed either during testing or between cycling thermal conditions. Rate of rise of T (re) was greater during exercise in the heat, but no significant difference in T (re) between conditions was observed at exhaustion. Mean values of RPE were consistently greater during exercise in the heat, but these differences did not reach statistical significance. These findings support the concept that rises in core temperature and/or brain perception (RPE) rather than circulatory insufficiency may be the critical factors defining limits to exercise in the heat.

Blood Pressure↗
PubMed1992

Incidence of sudden athletic deaths between 1985 and 1990 in Marion County, Indiana.

Relatively little information is available concerning the incidence of sudden death in athletes in the United States. The present study provides annual incidence rates of sudden athletic deaths in Marion County, Indiana, home of Indianapolis, the "amateur sports capital of the world." The overall incidence was 0.04% (18 athletic deaths in 44,481 forensic necropsies). This incidence varied slightly over the 6-year study period: 1985 (0.06%), 1986 (0.03%), 1987 (0.04%), 1988 (0.09%), 1989 (0%), 1990 (0.01%). Of the 18 sudden athletic deaths, 88% were cardiac in origin. A retrospective analysis of preparticipation screening efforts suggests that most of the cardiac conditions responsible for death could have been detected.

Adolescent↗
PubMed1993

[Infectious endocarditis, risk factors, prevention. Research group for infectious endocarditis and jury of the consensus conference].

Infective endocarditis, resulting from deposition of circulating microorganisms during a period of bacteremia on damaged endothelial heart valves, remains a serious disease. Its overall incidence did not decline in recent years, 24 cases/year/million inhabitants, in France. This can be explained by a modification of the type of underlying cardiac conditions with regression of rheumatic fever and increase of degenerative heart diseases, prosthetic valves and mitral valve prolapse. The risk of bacterial seeding on a damaged valve remains difficult to evaluate, the highest risk being for patients with prosthetic valve, previous infective endocarditis and cyanotic congenital heart disease. A case-control study, done in 1991, confirmed that procedures are risk factors for infective endocarditis and that the multiplicity of procedures increases the risk. A French consensus conference on the prophylaxis of infective endocarditis has updated the recommendations for antibiotic prophylaxis. Two groups of cardiac patients were identified, based on the incidence and the severity of endocarditis occurring in patients with these conditions, 1) patients considered at risk which require specific prophylaxis, and 2) patients considered non at risk which do not require antibiotic prophylaxis. Procedures which require antibiotic prophylaxis are dental procedures and specific gastrointestinal and urologic procedures. As complex protocols are associated with poor compliance by practitioners and patients, the jury has aimed for simplicity and feasibility.

Anti-Bacterial Agents↗
PubMed1983

[Use of digitalis in geriatrics: is it effective on the heart in sinus rhythm?].

The therapeutic activity of digitalis in cardiac failure is linked to its positive inotropic effect on the myocardium and its ability to control cardiac activity in atrial fibrillation. Chronic stimulation with digoxin in aged subjects with sinus rhythm, however, is of debatable utility Reference is made to a series of 35 subjects (mean age 76.5 yr) in sinus rhythm, 30 of whom had been taking digoxin for over 3 yr. Clinical and instrumental parameters were assessed and heart function was classified according to the NYHA arrangement. Subjects were randomly placed in two groups matched for sex, age and cardiac condition. The first group received digoxin, the second a placebo. No significant differences between the two groups were noted over a 3-month period. In keeping with the recent literature, it is felt that digitalis is not necessary for the dynamic cardiac control of aged subjects in sinus rhythm. In addition, it is suggested that hydrosaline retention in such subjects can be controlled by restriction of salt intake, rest and diuretics.

Aged↗
PubMed1995

Delayed development of conditioned heart rate responses to auditory stimuli in the rat.

This study examined heart rate responses to an auditory conditioned stimulus during development in the rat. The unconditioned stimulus (US) in all experiments was an acoustic startle stimulus. The conditioned stimulus elicited a monophasic bradycardia in animals 21 days of age and older, but no response in younger animals. These results are strikingly similar to an earlier study that used shock as the US (Campbell & Ampuero, 1985). Further, the conditioned cardiac response in adults was found to be mediated entirely through activation of the parasympathetic division of the autonomic nervous system (ANS) even though the US unconditionally activates the sympathetic system at that age. The delayed development of several different forms of conditioned fear is discussed.

Acoustic Stimulation↗
PubMed2004

Effect of remifentanil infusion rate on stress response to the pre-bypass phase of paediatric cardiac surgery.

BACKGROUND: Opioids are used routinely to eliminate the stress response in the pre-bypass phase of paediatric cardiac surgery. Remifentanil is a unique opioid allowing a rapidly titratable effect. No data are available regarding a suitable remifentanil dose regimen for obtunding stress and cardiovascular responses to such surgery. METHODS: We recruited 49 infants and children under 5 yr old who were randomized to receive one of four remifentanil infusion rates (0.25, 1.0, 2.5, or 5.0 micro g kg(-1) min(-1)). Blood samples were obtained at induction, pre-surgery, 5 min after opening the chest, and immediately pre-bypass. Whole blood glucose was measured at all time points while cortisol and neuropeptide Y (NPY) were measured in the first and last samples. Heart rate and arterial pressure were also recorded. RESULTS: There was a significant increase in whole blood glucose 5 min after opening the chest and pre-bypass (P=0.009, P=0.002) in patients receiving remifentanil 0.25 micro g kg(-1) min(-1), but not in those receiving higher doses. Increased remifentanil dosage was associated with reduced plasma cortisol during surgery (P<0.001). Baseline NPY showed considerable variation and there was no association between pre-bypass NPY and remifentanil dose. There was a significantly higher heart rate at the pre-bypass stage of surgery in the remifentanil 0.25 micro g kg(-1) min(-1) group compared with higher doses (P=0.0006). Four out of five neonates with complex cardiac conditions showed severe bradycardia associated with remifentanil. CONCLUSIONS: In infants and children under 5 yr, remifentanil infusions of 1.0 micro g kg(-1) min(-1) and greater can suppress the glucose increase and tachycardia associated with the pre-bypass phase of cardiac surgery, while 0.25 micro g kg(-1) min(-1) does not. Remifentanil should be used with caution in neonates with complex congenital heart disease.

Analgesics, Opioid↗
PubMed1993

Validating risk-adjusted mortality as an indicator for quality of care.

Risk-adjusted mortality is perhaps the most commonly referenced outcome indicator for assessments of hospital quality. While mortality rate possesses considerable intuitive appeal as a quality indicator, scientific evidence concerning its appropriateness for this purpose is mixed. In this paper, we use a computerized discharge database to model mortality risks for patients hospitalized for three different conditions: cardiac disease (ischemic heart disease, coronary artery disease, angina, and left ventricular aneurysm), acute myocardial infarction, and septicemia. We then use a database of peer review quality findings to determine whether the ratio of observed to expected deaths in each of these conditions relates validly to quality. The results of our analyses provide strong support for the validity of one of our mortality indicators, weak support for another, and no support for the third. We conclude that before inferences about hospital quality are made using any risk-adjusted mortality indicator, the validity of the quality/outcome relationship must be established explicitly for that measure.

Adult↗
PubMed2002

End tidal CO(2) is reduced during hypotension and cardiac arrest in a rat model of massive pulmonary embolism.

BACKGROUND: We investigated the effect of massive pulmonary embolism (MPE) on end tidal CO(2) (etCO(2)) and tested two hypotheses: (1) that etCO(2) can distinguish massive PE from hemorrhagic shock and (2) that PE with cardiac arrest reduces etCO(2) during resuscitation to a greater extent than arrhythmic cardiac arrest. METHODS: Anesthetized, mechanically ventilated rats (N=10 per group), were subjected to either graded PE (latex microspheres), or graded hemorrhagic shock to produce a final mean arterial blood pressure, (MAP) of 40 mmHg; a third group was subjected to surgical/anesthetic control conditions. Cardiac arrest was induced by the following methods: intravenous injection of a large bolus of microspheres in the PE group, aortic puncture in the hemorrhage group, and intravenous tetrodotoxin (TTX) to produce arrhythmic cardiac arrest in the control group. RESULTS: At a MAP of 40 mmHg, etCO(2) was significantly decreased in the PE group (18.3+/-1.9 torr) compared with both the hemorrhage (24.3+/-1.3) and the control group (35.0+/-1.3 torr; ANOVA P<0.001). The decreased etCO(2) occurred coincident with an increase in alveolar dead space fraction in the PE group. In the first minute of ventilation after cardiac arrest, the etCO(2) was significantly decreased in the PE group (6.5+/-0.9) versus both hemorrhage (16.5+/-1.1) and TTX (34.2+/-2.4 torr). CONCLUSIONS: Massive PE with shock decreases the etCO(2) and increases the dead space fraction to a greater extent than hemorrhagic shock at the same MAP. Cardiac arrest from PE is associated with extremely low etCO(2) readings during CPR.

Analysis of Variance↗
PubMed2002

Transfusion practices for elective orthopedic surgery.

BACKGROUND: Use of blood conservation techniques in elective surgery reduces the risk of infection and transfusion reactions that result from using allogeneic blood products. We examined the transfusion practice and blood conservation strategies for elective orthopedic procedures in 19 Canadian hospitals. METHODS: We reviewed the medical records of patients who underwent total hip or knee joint arthroplasty between June 1998 and January 1999 in a convenience sample of 19 hospitals to determine the pre- and postoperative hemoglobin concentrations, concurrent medical conditions, participation status in an autologous blood donation program, use of other blood conservation techniques, and occurrence of allogeneic and autologous transfusions. Patients were considered eligible for autologous blood donation if they weighed at least 25 kg, were in good general health without major cardiac conditions and had a hemoglobin concentration of at least 110 g/L. RESULTS: We reviewed 4535 medical records. Of the 4422 patients whose eligibility status was known, 2561 (57.9%) were eligible to participate in an autologous blood donation program. Only 842 (18.6%) of the patients predonated blood. Patients who did not predonate blood were older (mean age 70.1 v. 63.8 years) and were more likely to have concomitant medical conditions (60.3% v. 37.9%) than those who did predonate. Overall, 30.6% (95% confidence interval [CI] 29.1%-32.1%) of the patients who did not predonate blood received allogeneic transfusions. For patients who predonated, the rate of allogeneic transfusion was 14.1% (95% CI 11.8%-16.5%). The frequency with which blood conservation techniques other than autologous blood donation were used was minimal (in 2.4% of all cases). INTERPRETATION: The use of blood conservation techniques among hospitals in Canada remains low. Only a minority of eligible patients participated in an autologous blood donation program.

Aged↗
PubMed2002

Functional and psychological recovery during intensive hospital rehabilitation following cardiac surgery in the elderly.

UNLABELLED: The recovery process in the elderly after cardiac surgery is influenced not only by clinical cardiac conditions, but also by comorbidity, cognitive decline and disability. We evaluated the relationship between clinical objective and self-perceived factors and their influence on functional recovery in 204 consecutive, over-70s pts who were admitted into an intensive hospital rehabilitation program following cardiac surgery. The variables taken into consideration were: comorbidity (Charlson index), length of hospital stay and complications in cardiac surgery and rehabilitation, disability (nursing needs score index), functional status (6-min walking test), left ventricular EF, number of training sessions, self-perceived health status (EuroQol questionnaire), emotional impairment (anxiety/depression, CBA-2.0/interview). RESULTS: Functional capacity: the distance walked was 198 +/- 103 m at admission and 287 +/- 121 m at discharge (p < 0.0001). Only the nursing needs score index resulted as a weak, independent predictor of the distance walked at admission (r2 = 0.14, p < 0.001, beta = 0-.21), which (beta = 0.49), together with complications during rehabilitation (beta = -0.15), self-perceived health status at discharge (beta = 0.15) and number of training sessions (beta = 0.20), was independently correlated with the distance walked at time of discharge (r2 = 050, p < 0.0001). Patients mood: anxiety correlated with depression. Emotional scores did not correlate with functional measures. Patients self-perceived health status: only the nursing needs score index was a weak, independent predictor of well-being at entry (r2 = 0.15, p < 0.0001, beta = -0.29), which, in turn, was the only predictor of perception at discharge (r2 = 0.33, p < 0.0001, beta = 0-.42). CONCLUSIONS: In an intensive hospital rehabilitation program following cardiac surgery in patients over 70 a) there was no correlation between clinical and psychological variables; b) anxiety and depression were associated, but neither influenced the recovery process nor correlated to health status perception; c) functional impairment was strongly influenced by nursing needs which also affected the self-perceived health status; d) both functional and perception recovery were influenced by disability at time of admission and reacted positively after rehabilitation.

Age Factors↗
PubMed2006

Anaesthesia for caesarean section in patients with cardiac disease.

This review contains material sourced from Med-Line and Pub-Med, search year 2002-2004. Material selected was pertaining to common cardiac ailments in pregnancy. Congenital cardiac problems i.e. Tetralogy of Fallot (TOF), Atrial Septal Defect (ASD), Ventricular Septal Defect (VSD), Eisenmengers syndrome, valvular heart disease, i.e. mitral stenosis, mitral regurgitation, aortic stensois and aortic regurgitation are discussed. Other cardiac conditions associated with pregnancy are pulmonary hypertension and peri-partum cardiomyopathy. Arrhythmias during pregnancy, vary from isolated premature to supra-ventricular and ventricular tachycardia, management is similar to non-pregnant patients. This review summarizes the current management of a parturient with cardiac disease requiring surgical delivery. Regional anaesthesia techniques are preferred as reflected in the current literature for patient with cardiac disease with minor alterations such as slow establishment of epidural for caesarean section or continuous spinal anaesthesia with very small incremental doses of local anaesthesia, maintaining the patient's SVR with vasopressors and fluid, monitoring of the fluid regimen with CVP and in some cardiac function with Swan Ganz catheter. Patients with Eisenmenger syndrome, pulmonary hypertension, should be advised to avoid pregnancy. In conclusion with vast advancements in obsterics care, improvements in cardiac surgery, many patients with cardiac disease can now be safely delivered surgically by skillful anaesthesiologists who are aware of the common potential intra-operative problems and the ability to respond to undesired events immediately.

Anesthesia, Obstetrical↗
PubMed1978

Physiological effects of lowered blood oxygen affinity in dogs.

Ten adult Labrador retrievers were studied under control conditions and while blood oxygen affinity was lowered by intravenous infusions of glycolytic intermediates. Blood P50 was increased from 32.4 +/- 1.3 mm Hg (mean +/- SD) to 34.3 +/- 1.2 mm Hg, a highly significant increase (P less than 0.001). Blood oxygen capacity, mixed venous oxygen tension and arterial PCO2 were not significantly different in the two conditions. Cardiac output (Q) was lower with the higher P50 (89 +/- 16 ml/kg/min) than in the control state (111 +/- 31 ml/kg/min) but the difference was not statistically significant. The arteriovenous oxygen concentration difference (CaO2 - C-V(O2)) was significantly increased (P less than 0.05) from 4.4 +/- 0.6 vol % to 4.9 +/- 0.8 vol %. Oxygen consumption, the product of Q and (CaO2 - C-V(O2)), was the same in the two conditions: 4.9 +/- 1.3 ml/kg/min (control) versus 4.4 +/- 0.9 ml/kg/min. The animals responded to lowered blood oxygen affinity with increased oxygen extraction by peripheral tissues and a concomitant, although not statistically significant, fall in cardiac output.

Animals↗
PubMed2001

Measurements of hyperpolarized gas properties in the lung. Part III: (3)He T(1).

Hyperpolarized (3)He spin-lattice relaxation was investigated in the guinea pig lung using spectroscopy and imaging techniques with a repetitive RF pulse series. T(1) was dominated by interactions with oxygen and was used to measure the alveolar O(2) partial pressure. In animals ventilated with a mixture of 79% (3)He and 21% O(2), T(1) dropped from 19.6 sec in vivo to 14.6 sec after cardiac arrest, reflecting the termination of the intrapulmonary gas exchange. The initial difference in oxygen concentration between inspired and alveolar air, and the temporal decay during apnea were related to functional parameters. Estimates of oxygen uptake were 29 +/- 11 mL min(-1) kg(-1) under normoxic conditions, and 9.0 +/- 2.0 mL min(-1) kg(-1) under hypoxic conditions. Cardiac output was estimated to be 400 +/- 160 mL min(-1) kg(-1). The functional residual capacity derived from spirometric magnetic resonance experiments varied with body mass between 5.4 +/- 0.3 mL and 10.7 +/- 1.1 mL. Magn Reson Med 45:421-430, 2001.

Animals↗
PubMed1993

In vivo deleterious effects of a right shift of the HbO2 curve during hypoxemia.

We investigated the influence of a right shift of the oxyhemoglobin dissociation curve on tissue oxygenation in two groups of anesthetized rabbits subjected to short periods of graded hypoxia: Group 1 (n = 5) with elevated P50 due to increased RBC 2,3-diphosphoglycerate and adenosine triphosphate and Group 2 (n = 5) with normal P50. Hemoglobin fell progressively in all animals due to blood letting for necessary measurements. During 16% inspired O2 (FIO2), both groups remained stable. During 13% FIO2, arterial pO2 was the same in both groups, but only in Group I did it fall below the crossover point (C.O.P.), which was raised by the high P50. Arterial pH and arterial-venous O2 content difference remained within the normal range in both groups throughout the experiment. During 13% FIO2, animals with high P50 showed a fall in cardiac output and oxygen consumption while animals with normal P50 remained stable. We postulate that when systemic O2 content is sufficiently reduced and tissue O2 extraction is maximal, the O2 needs of the myocardium perfused with a pO2 below the C.O.P. cannot be met: under these conditions cardiac output and systemic O2 consumption fall, presumably due to a reduction in coronary blood flow.

2,3-Diphosphoglycerate↗