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

Intraoperative mapping of the specialized atrioventricular conduction system was performed in 47 patients during cardiac surgery. Specialized conduction tissue electrograms were identified in 37, and atrioventricular conduction preserved in 92%. Specialized conduction tissue was identified in 27 patients with atrioventricular canal defect: complete heart block was avoided in 25. Conduction tissue was located in six of 12 patients with complex transpositions; atrioventricular conduction was preserved in all six. Other lesions in which the technique was useful were Ebstein's anomaly and single atrium. Limitations to the technique are 1) deep hypothermia and circulatory arrest; 2) interruption in atrioventricular conduction during mapping; 3) inadequate exposure and access to probable sites of conduction tissue; 4) variation of size and spatial relations of individual malformations; and 5) limited time for identification of unusually located conduction tissue. Indications for use of this technique include patients with both forms of atrioventricular canal, complex transpositions, atrioventricular discordance, single ventricle and single atrium.
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PMID:Intraoperative recording of specialized atrioventricular conduction tissue electrograms in 47 patients. 75 7

Electrocardiographic and electron microscopic alterations in the myocardium were investigated in rats subjected to hypothermia with and without injection of dextran. Twenty-two animals were divided into four groups and studied. The first group of five rats served as the control group. The second group of six rats, which were subjected to total body hypothermia developed arrhythmia (from first degree atrioventricular block to complete heart block) at a mean rectal temperature of 18 degrees C., with prolongation of P,P-R, and QRS duration, as well as a marked separation of intercalated discs, articularly at the level of the fascia adherens. The third group of six rats was subjected to hypothermia and to an injection of dextran. The resulting threshold temperature tthe temperature at which the arrhythmia appeared) was lower (16 degrees C.) than in the preceding group (p less than 0.005), but neither advanced atrioventricular block nor remarkable subcellular structural changes developed. The fourth group of five rats was sacrificed 18 to 24 hours following recovery from hypothermia and, at that time, showed no significant electrocardiographic or electron microscopic alterations.
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PMID:Myocardium of hypothermic rats with and without administration of dextran. Electrocardiographic and electron microscopic studies. 116 Mar 53

One hundred fifty seven consecutive octogenarians (mean age +/- standard deviation, 82.4 +/- 1.9 years) underwent coronary artery bypass grafting with hypothermia (mean temperature, 21.8 degrees +/- 1.8 degrees C), hyperkalemic cardioplegia, and cardiopulmonary bypass in a 9-year period. Sixty-six percent were male. Preoperatively, 115 patients (73%) were in New York Heart Association functional class IV, with the remainder being in either class III (23%) or class II (4%). Twenty percent of the patients had major complications including postoperative hemorrhage (15), sepsis (9), cerebrovascular accident (6), third-degree heart block (5), renal failure requiring dialysis (1), and pulmonary embolism (1). The 30-day or in-hospital mortality rate was 7.0%. Mean total hospital stay was 26.1 +/- 17.9 days. One-year and 5-year actuarial survival rates were 85% and 62%, respectively. Higher mortality was seen to be associated with New York Heart Association class IV, left ventricular ejection fraction less than 0.40, and lesser values for cardiac output and cardiac index. At the 6-month postoperative follow-up, 73% of the survivors reported that their general health had improved as compared with before operation. This experience demonstrates that for select octogenarians with unmanageable angina pectoris, coronary artery bypass grafting is an effective therapeutic option.
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PMID:Morbidity and mortality after coronary artery bypass in octogenarians. 203 31

Myotonia is defined as a persistent contraction of skeletal muscles after their stimulation. This contracture is not prevented or relieved by regional anaesthesia or muscle relaxants. The sensitivity to non-depolarizing muscle relaxants is usually normal. Suxamethonium, neostigmine, hypothermia, a rise in kalaemia should be avoided. There have been case reports of malignant hyperthermia in patients with myotonia congenita. Dystrophia myotonica is the second most frequent of the inherited muscle diseases, after Duchenne's dystrophy. The severity of the disease is due more to the muscular atrophy and the multiple organ involvement than to the abnormal contraction. Atrioventricular heart block and dysrhythmias are more common than heart failure. Prolonged apnoea and pneumonia are the main risks of anaesthesia. In severe cases, exists a restrictive respiratory insufficiency which is preceded by a fall in the maximum expiratory pressure. Dysphagias and inefficient coughing may occur early. An increased susceptibility to hypnotic drugs and opiates is a common feature. Spontaneous sleep apnoeas should be sought before anaesthesia, especially by using pulse oximetry. The anaesthetic implications are reemphasized.
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PMID:[Anesthesia in myotonia]. 253 24

Between October 1984 and January 1993, seven children of Jehovah's Witnesses underwent corrective open-heart surgery for congenital defects, on cardiopulmonary bypass (CPB). Age at surgery ranged from three months to 6.5 years, and weight ranged from 4.2 kg to 23.2 kg, with two children weighing less than 10 kg. The principal cardiac anomalies were tetralogy of Fallot (two), double outlet right ventricle (one), subaortic stenosis (one), transposition of the great arteries and ventricular septal defect (one), atrial septal defect and congenital heart block (one), and congenital mitral regurgitation (one). Hypothermic CPB was used in all seven operations with crystalloid priming of the extracorporeal circuit. CPB was based on our standard perfusion protocols. All surgical procedures were done without the use of blood or blood products. The mean preoperative haematocrit (Hct) was 40.9% (range 31.0-47.8%). The mean lowest intraoperative Hct was 17.3% (range 15.0-24.3%), whereas the immediate post-CPB Hct was 19.6% (range 15.3-24.0%). The Hct progressively increased to 29.2% (range 21.0-34.2%) on the first postoperative day, and 32.3% (range 24.2-38.3%) at the time of discharge. There was no hospital mortality, and the mean hospital stay was 10 days (8-13 days). We report the safe repair of complex open-heart surgery in children, without blood transfusion, even in small infants. The successful management of these patients requires meticulous attention to surgical and perfusion technique, and sound postoperative management.
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PMID:Bloodless open-heart surgery in infants and children. 798 63

The development of open-heart surgery has been reviewed beginning with general body hypothermia and inflow stasis, then continuing with extracorporeal circulation by controlled cross-circulation. The successes with the latter technique stimulated rapid development of the simple disposable highly effective bubble oxygenator for extracorporeal circulation to permit correction of virtually all forms of congenital and acquired heart disease. For the few conditions not amenable to corrective procedures, heart replacement became a practical reality. The creation of chronic heart block in the early operations had a very deleterious effect upon survival until highly effective electrical pacing was developed.
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PMID:The Society Lecture. European Society for Cardiovascular Surgery Meeting, Montpellier, France, September 1992. The birth of open-heart surgery: then the golden years. 804 65

The long-term results of primary closure for large ventricular septal defects (VSDs) in infants under 1 year of age with severe symptoms were studied over a period of more than 10 years. Between January, 1971 and March, 1982, 49 infants underwent primary closure of a VSD through a right ventriculotomy using complete cardiopulmonary bypass with mild hypothermia. There were four hospital deaths but no late deaths. Two of four infants with residual shunts had a left ventricular-right atrial shunt which necessitated reoperation. Surgical heart block occurred in two infants who recovered sinus rhythm in the late period. The cardiothoracic ratio decreased from 60.5% preoperatively to 50.6% in the late postoperative period. Examination by cardiac catheterization revealed that the pulmonary-to-systemic pressure ratio (Pp/Ps) of 23 patients with a Pp/Ps of over 0.75 fell from 0.89 +/- 0.09 preoperatively to 0.42 +/- 0.12 by 1 month postoperatively, then to 0.27 +/- 0.05 in the late postoperative period. The latest values for the cardiac index and left ventricular ejection fraction were 3.4 l/min per m2 and 64.4%, respectively. More than 10 years after their operation, all the survivors were growing normally and maintaining a good quality of life, which supports our recommendation that primary repair should be performed in the first year of life for infants with large VSDs.
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PMID:Long-term results of primary closure for ventricular septal defects in the first year of life. 805 7

While the development of pharmacological cardioplegic solutions for myocardial protection during cardiopulmonary bypass (CPB) have significantly lengthened the safe operating time for cardiac surgical procedures, the introduction of hypothermic hyperkalemic cardioplegia (CPG) has markedly increased the incidence of postoperative arrhythmias and conduction abnormalities. Using a customized modification of a computerized mapping system, we have developed a large animal porcine model of CPB that is exquisitely sensitive to the electrophysiological (EP) derangements imposed by ischemia and cardiac arrest. This model is able to measure spatial and temporal parameters of ventricular activation with high resolution, using an array of up to 84 epicardial electrodes that can be reproducibly placed on the surface of the heart utilizing known epicardial anatomical markers (e.g., coronary arteries). With this system we have measured the spectrum of clinically observed EP disturbances caused by CPG, from slowed intraventricular conduction to complete heart block. Compared to the control group of hypothermia alone, 2 hours of crystalloid CPG arrest had a significant slowing effect on ventricular activation (p < 0.05). CPG was accompanied, in each animal, by profound changes in the spatial distribution of ventricular activation and persistent slowing of ventricular activation. Traditional EP parameters of effective refractory period and pacing threshold were unchanged by CPG. Smaller temporal and spatial changes were observed in the control group, but were always reversed by 90 minutes of warm reperfusion. We conclude that CPG induces injury of the specialized conducting system and, to a lesser degree, the myocardium. This model will afford us the opportunity to test new methods of CPG to further improve myocardial preservation during CPB.
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PMID:Electrophysiological consequences of hypothermic hyperkalemic elective cardiac arrest. 846 98

The goals for repairing complete atrioventricular canal (atrioventricular septal defect) are ventricular septation, atrial septation, mitral valve reconstruction, and tricuspid valve reconstruction. Complications to avoid are heart block, residual septal defects, and dysfunctional atrioventricular valves. The surgical repair of atrioventricular canal has undergone major advances over the past 40 years. Excellent short- and long-term results have been achieved with both the single-patch technique and the two-patch technique. The single-patch technique is accomplished by dividing the common valve leaflets into their respective tricuspid and mitral components, suspending them from a single patch used to close the atrial and ventricular septal defects. The two-patch technique uses a prosthetic patch for the ventricular septal defect, a pericardial patch for the atrial septal defect, and suture closure of the anterior mitral cleft. Other variables include the use of deep hypothermia and circulatory arrest, mitral cleft closure, interrupted versus continuous suturing technique, and age at operation. Perhaps more important than the applied method is that the operation be properly executed to ensure defect closure and competent valves. We review our experience in 120 patients using the two-patch technique with special reference to the technical aspects of the operation. The two-patch technique of repair with routine cleft closure as evaluated by intraoperative transesophageal echocardiography results in a low surgical mortality, a low incidence of permanent heart block, and competent atrioventricular valves.
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PMID:The two-patch technique for complete atrioventricular canal. 910 23

With the loyal support of the chair of Surgery, Dr. Owen H. Wangensteen, the University of Minnesota cardiac surgery program led the way at the dawn of cardiac surgery when Dr F. John Lewis performed the first open heart surgery in the world using hypothermia while repairing an atrial septal defect on September 2, 1952. Soon after, Dr C. Walt Lillehei performed the first repair of a ventriculoseptal defect in the world using cross-circulation on March 26, 1954. Collaborating with Dr Richard DeWall in 1955, they developed the DeWall-Lillehei bubble oxygentor which was used at the University of Minnesota and many other centers worldwide for years to come, making open heart surgery safe and tractable. Dr Vincent Gott, a resident working in the laboratory of Lillehei, developed a method to treat complete heart block using ventricular pacing with a Grass physiological stimulator, and this led to a collaboration with Earl Bakken, founder of the Medtronic Corporation, to develop a temporary pacemaker. The program was fertile ground for many notable trainees, including Dr Norman Shumway, the "Father of Heart Transplant", and Dr Christiaan Barnard who performed the first heart transplant in the world. The collegial and forward thinking nature of the cardiac surgery program continues in the current training program today.
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PMID:Great Institutions in Cardiothoracic Surgery: The University of Minnesota. 2828 78


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