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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 53 patients with mitral- or aortic-mitral valve disease, the content of ATP and lactate of the papillary muscles resected at the time of valve replacement was investigated at the beginning of ischemic arrest and at the time of reperfusion. Profound body hypothermia (25 degrees C) and injection cardioplegia using magnesium-aspartate-procaine were applied for myocardial protection. In hypertrophic papillary muscles the myocardial ATP content decreased at a slower rate (ATP decay 12% of the initial value after 60 minutes of ischemia) than in normal papillary muscles obtained from patients with isolated mitral stenosis (ATP decay 33% of the initial value after 40 minutes of ischemia). 20% of the patients required temporary inotropic circulatory support postoperatively for 12 to 88 hours. The ATP content of the papillary muscles of these patients differed only little from those, in who no myocardial failure occurred. However the myocardial lactate levels were higher in patients in whom a low cardiac output state evolved.
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PMID:[Behaviour of ATP and lactate in human papillary muscle during profound hypothermia and injection cardioplegia with magnesium-asparatate-procaine (author's transl)]. 75 Dec 88

The isovolumic relaxation time (IVRT) is an important noninvasive index of left ventricular diastolic function. Despite its widespread use, however, the IVRT has not been related analytically to invasive parameters of ventricular function. Establishing such a relationship would make the IVRT more useful by itself and perhaps allow it to be combined more precisely with other noninvasive parameters of ventricular filling. The purpose of this study was to validate such a quantitative relationship. Assuming isovolumic relaxation to be a monoexponential decay of ventricular pressure (pv) to a zero-pressure asymptote, it was postulated that the time interval from aortic valve closure (when pv = p(o)) until mitral valve opening (when pv = left atrial pressure, pA) would be given analytically by IVRT = tau[log(p(o))-log(pA)], where tau is the time constant of isovolumic relaxation and log is to the base e. To test this hypothesis we analyzed data from six canine experiments in which ventricular preload and afterload were controlled nonpharmacologically. In addition, tau was adjusted with the use of beta-adrenergic blockade and calcium infusion, as well as with hypothermia. In each experiment data were collected before and after the surgical formation of mitral stenosis, performed to permit the study of a wide range of left atrial pressures. High-fidelity left atrial, left ventricular, and aortic root pressures were digitized, the IVRT was measured from the aortic dicrotic notch until the left atrioventricular pressure crossover point, and tau was calculated by nonlinear least-squares regression.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Isovolumic relaxation time varies predictably with its time constant and aortic and left atrial pressures: implications for the noninvasive evaluation of ventricular relaxation. 144

Similarly as in all war-ravaged countries of Europe, in Czechoslovakia, too, cardiosurgery did not begin being systematically developed until after 1945. Patent ductus arteriosus was first treated surgically in this country in 1947, the year 1951 saw the launching of surgical therapy for mitral stenosis (commissurotomy on the closed heart), 1955 - the introduction into clinical practice of open-heart surgery for simple heart defects (DSS, pulmonary artery stenosis and aortic stenosis) with the patient in 28 degrees C hypothermia and with the blood circulation arrested for brief periods of time. In the years 1958-1959, four Czechoslovak cardiosurgical centres began to provide surgical treatment for congenital and acquired heart defects in extracorporeal circulation. Considering the war-inflicted material and personnel shortcomings prevailing in those times, Czechoslovak cardiosurgery managed relatively soon to attain the standard of cardiosurgery of the western countries, thus testifying to the viability of the country's post-war health care services. At present, there are six cardiosurgical centres in this country systematically engaged in the surgical treatment of congenital and acquired heart defects and providing the diagnosis and surgical correction of heart defects on a professional scale equal to that in countries with advanced health care systems. While the care provided at Czechoslovak cardiosurgical centres is comparable in terms of quality, the productivity of those centres leaves much to be desired. Ways and means of coping early with this inadequacy are looked for with the help of the Ministry of Health.
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PMID:Czechoslovak cardiosurgery. 207 Jun 91

During the development of methods to protect the heart from ischaemic injury, attention has been focused on protection of the left ventricle. In an attempt to assess right heart preservation. 55 consecutive patients undergoing open heart surgery were studied. Mean aortic cross-clamp time was 59.3 +/- 29.4 min. Temperature probes were inserted into the right atrium (RA), right ventricle (RV), and left ventricle (LV). During cardioplegia, the mean myocardial temperatures of RA, RV and LV were 19.1 degrees +/- 4.1 degrees C, 12.7 degrees +/- 4.8 degrees C and 7.3 degrees +/- 3.4 degrees C, respectively. Of the LV temperature measurements, 67.2% were 10 degrees C or lower. By contrast, 94.1% of RA measurements and 58.5% of RV measurements were above 10 degrees C. The inhomogeneity of chamber temperatures was observed irrespective of the patient's disease or age and whether the atrium or right ventricle were open or not. Hearts with mitral regurgitation (MR), in contrast to mitral stenosis and stenoinsufficiency, had higher LV temperatures, similar to those in the RV. We conclude that there is uneven hypothermia among the three cardiac chambers during hypothermic cardioplegic arrest, regardless of disease states except MR and regardless of age and procedure performed.
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PMID:Uneven myocardial hypothermia among cardiac chambers during hypothermic myocardial preservation. 226 42

Craniocerebral hypothermia was used during open-heart surgery in 69 patients with mitral stenosis (hospital mortality rate 2.9%). Indications for open-heart surgery (left atrial thrombosis, mitral valve calcinosis, onset of traumatic mitral insufficiency) were determined intraoperatively during closed mitral commissurotomy. Some pathophysiological peculiarities of craniocerebral hypothermia were studied. A decrease in brain temperature and total oxygen consumption (up to 27.7% of the basic metabolism level) has been observed. Prolongation (up to 25 min) of major vessel occlusion had no negative effect on the patients' condition, postoperative complications and lethality. Craniocerebral hypothermia is considered to be a safe and effective technique indicated in case of emergency for open-heart surgery.
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PMID:[Emergency craniocerebral hypothermia in the management of open mitral commissurotomy]. 239 75

During the mitral valve replacement on a 48-year-old male with mitral valve stenosis, ST-T changes (ST elevation and T inversion) suddenly appeared just before the start of cardiopulmonary bypass. Myocardial ischemia was suspected before we noticed the cardioplegic solution (about 10 degrees C) had been dripping on the surface of the right ventricle by mistake for about five minutes. After pouring warm saline over the myocardial surface, the EKG returned to normal within ten minutes. In this case, there appeared the elevation of the J point which is characteristic of profound hypothermia and is easily mistaken as myocardial ischemia because of ST segment elevation. It is very important to observe even a trivial intraoperative action which is not directly related with the operative procedure.
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PMID:[Intraoperative ST-T changes resembling myocardial ischemia due to accidental myocardial cooling]. 272 25

Twenty five consecutive patients with complete atrioventricular canal (CAVC) underwent one-stage operation from April 1981 to Aug. 1987. Average ages at operation was 18 months (2 to 72) and average weight was 7.0 kg (2.8 to 13.8). Fifteen patients were infants and fifteen had Down syndrome. Conventional cardiopulmonary bypass with pulsatile bypass pump (PBP) and moderate hypothermia at 28 degrees C was utilized in all patients. Single patch technique (SPT) was adopted for initial five patients and two patch technique for the latter twenties. Two patients died perioperatively (operative mortality 8.0%), one of whom from mitral stenosis after SPT and the other from misdiagnosis of large subpulmonary VSD. There was no hospital death. Mean pulmonary artery pressure (mPA), pulmonary systolic pressure to systemic systolic pressure ratio (Pp/Ps) and pulmonary vascular resistance index (PVRI) were decreased remarkably from preoperative values of 56 +/- 14 mmHg, 0.92 +/- 0.13 and 6.2 +/- 4.9 WU.m2 to postoperative of 31 +/- 16 mmHg (p less than 0.001), 0.54 +/- 0.20 (p less than 0.001) and 4.6 +/- 4.0 WU.m2 (NS), respectively. Six patients had residual pulmonary hypertension in which mPA was more than 40 mmHg. One patient who was complicated with severe mitral regurgitation due to dehiscence of suture line and torn chordae had mitral valve replacement. Mean follow-up period was 26 months (5 to 63). The mean weights of 67%N at operation catched up with 87%N 3 years after operation. There were two late deaths, 4 and 20 months after operation between age at operation, both of whom had residual pulmonary hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Total repair of complete atrioventricular canal: relationship between age at operation and late results]. 276 5

To evaluate intraoperative changes in myocardial performance during valvular operations, ventricular functional measurements were obtained in 16 patients before and after elective cardiac valvular replacement. Six patients had mitral regurgitation, four had mitral stenosis, and six had calcific aortic stenosis; all patients underwent isolated mitral or aortic valve replacement. Cold potassium crystalloid cardioplegia, topical hypothermia, and low-flow systemic hypothermia were employed uniformly. Just before and 10 minutes after cardiopulmonary bypass was discontinued, left ventricular pressure and volume data were recorded at four to five different steady-state levels of filling produced by blood infusion or withdrawal from the aortic cannula (mean end-diastolic pressure range, 10-22 mm Hg; mean end-diastolic volume range, 120-168 ml). Portable first-pass radionuclide ventriculography and simultaneous micromanometry were used for construction of left ventricular pressure-volume loops from which stroke work and end-diastolic volume were calculated. Two-dimensional transesophageal echocardiograms also were recorded, and epicardial pacing maintained heart rate as constant as possible. As compared with prebypass measurements, echocardiographic left ventricular wall volume changed insignificantly after the valvular procedures (178-181 ml/m2, p greater than 0.5). The stroke work-end-diastolic volume relationship before and after operation was highly linear in all studies (mean = 0.97). The slope and x intercept of this relationship did not change significantly after operation, indicating a stable level of left ventricular function (from 12.7 x 10(4) to 10.0 x 10(4) ergs/ml and from 67 to 57 ml, respectively; p greater than 0.3).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Assessment of left ventricular functional preservation during isolated cardiac valve operations. 280 86

A total of 102 patients aged 65 to 78 years underwent valvular replacement between 1975 and 1980. Calcific aortic stenosis was, by far, the commonest lesion (54 cases), followed by mitral stenosis (16 cases), mitral incompetence (14 cases), aortic incompetence (10 cases) and double valve lesions (8 cases). Sixty four patients underwent aortic valve replacement with 7 early deaths (10,9 p. 100). There were 30 mitral valve replacements with 7 deaths (23,3 p. 100) and 8 patients had double valve surgery with 4 deaths (50 p. 100). Aorto-coronary bypass grafting was associated in 25 cases with a 20 p. 100 mortality. Changes in the technique of peroperative myocardial protection have considerably reduced early mortality which has fallen from over 20 p. 100 to 2,9 p. 100 since the use of cardioplegia with local and systemic hypothermia. There was a higher surgical mortality in patients with poor left ventricular function, cardiomegaly and severe symptomatic incapacity. Non-fatal postoperative complications were common (50 p. 100 of survivors). There were 12 late deaths, 75 p. 100 of which were related to cardiovascular causes. The actuarial survival rate was 65,5 +/- 6 p. 100, 5 years after surgery. When operative mortality was excluded, the 5 year survival rate of the operated patients did not differ from that of the general populations of the same age (79,8 p. 100). Only 5 of our patients were lost to follow-up. Of the survivors, 95,5 p. 100 were asymptomatic or improved by at least one functional grade after an average postoperative period of 30 months. The incidence of late haemorrhagic complications in patients on anticoagulants was 11 p. 100.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Valve replacement in aged patients. Risk and remote results]. 641 7

The left ventricular myocardium excised from 14 patients who had mitral stenosis and who underwent mitral valve replacement was examined, and myocardial fibrosis was quantitated in relation to cardiac function. Conventional mitral valve replacement was performed with cold potassium-induced cardioplegia associated with systemic hypothermia (28 degrees C rectal temperature) and topical cooling. All 14 patients had perivascular fibrosis; the amounts ranged from 16% to 54% of the whole tissue excised. The mean left ventricular end-diastolic volume index (LVEDVI) determined by M-mode echocardiography increased significantly (p less than 0.001) from 66.9 +/- 4.6 ml/m2 preoperatively to 79.0 +/- 2.9 ml/m2 postoperatively. The difference between preoperative and postoperative LVEDVIs was significantly correlated (p less than 0.01) to the percentage of myocardial fibrosis (r = 0.72), in that the index increased postoperatively when myocardial fibrosis was more than 35% and decreased when fibrosis was less than 35%. After mitral valve replacement, the mean ejection fraction increased when fibrosis was less than 35% of whole tissue (+0.12 +/- 0.04) and decreased when fibrosis was greater than 35% (-0.02 +/- 0.02, p less than 0.01). No measured preoperative hemodynamic parameters were predictive of prognosis. These data suggest that the degree of myocardial fibrosis is related to left ventricular performance after mitral valve replacement.
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PMID:Relationship between left ventricular morphology and postoperative cardiac function following valve replacement for mitral stenosis. 684 53


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