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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of hydrocortisone on left ventricular force-velocity relations, systolic length-tension curves, and diastolic pressure-volume curves (compliance) were determined before and 30 and 60 minutes after a 1 hour period of normothermic ischemic cardioplegia. Five dogs were given no hydrocortisone, 5 dogs 150 mg. per kilogram of hydrocortisone immediately after aortic unclamping, and 5 dogs 150 mg. per kilogram of hydrocortisone 20 minutes before clamping. Thirty minutes after unclamping, there was a 45 per cent decrease in contractility (p less than 0.005). At 60 minutes, there was a significant improvement (p less than 0.025), although a 32 per cent depression persisted. There were no differences among the three groups (p less than 0.05). Dogs not given hydrocortisone before clamping, compliance decreased 18 per cent (p less than 0.05), and in those given hydrocortisone immediately after unclamping, compliance decreased 28 per cent (p less than 0.025). The decreases in compliance in the hydrocortisone-treated dogs were significantly less (p less than 0.05) than the decreases observed in the dogs not given hydrocortisone.
J Thorac Cardiovasc Surg 1975 Sep
PMID:Effects of myocardial ischemia on ventricular compliance. Protective role of hydrocortisone. 116 38

Chronic left ventricular-atrial regurgitation (LVAR) was created in 8 dogs by means of an external conduit so that the effects of acute correction of regurgitation on the mechanics of left ventricular performance could be studied in detail. LVAR of 46 to 77 per cent of the total left ventricular (LV) output was associated with a depression of the LV inotropic state (downward displacement of the stress-velocity relationship, reduction in V max), reduced forward flow, and signs of cardiac failure. Acute occlusion of the shunt (analogous to return of mitral valvular competence) in the anesthetized, open-chest animal resulted in a statistically significant increase in the integrated LV systolic wall stress (afterload), which averaged 18 per cent. In the dog with greatest depression of the LV inotropic state, the increase in afterload was associated with a decrease in forward flow. Occlusion of the shunt had no significant effect on the inotropic state. This model of mitral regurgitation appears to be useful in assessing the effect of chronic LVAR on cardiac performance and may explain the hemodynamic deterioration observed in some patients with severe mitral regurgitation following valve replacement.
J Thorac Cardiovasc Surg 1975 Sep
PMID:Experimental mitral regurgitation: effects on left ventricular function before and after elimination of chronic regurgitation in the dog. 116 39

As shown by the inotropic changes, the sympathetic discharge on the heart, is selectit syndrome. In the steady state the electrocardiogram shows flat, diphasic, or "tucked' T waves. Mental stimulation or isoproterenol, and, respectively, pain or beta blockade induce changes of the repolarization phase divergent from steady state. The former causes ST depression and deep T-wave inversion and the latter fully normalizes the repolarization phase. It is concluded that the electrical activity of the heart is directly influenced by the adrenergic drive in this disorder, and that different stressful factors can alter the repolarization phase in opposite ways in relation to the influence of the stimulus on the cardiac sympathetic tone.
Cardiovasc Res 1975 May
PMID:Stress-induced and sympathetically-mediated electrocardiographic and circulatory variations in the primary hyperkinetic heart syndrome. 117 81

In order to assess the long-term effects of cardiopulmonary bypass (CPB) in combination with pupular methods of myocardial protection, 37 dogs were placed on CPB for 100 minutes with the use of a bubble oxygenator without hemodilution. A separate group (I) of eight normal dogs served as a control for assessment of hemodynamic changes. The operative groups were as follows: II, continuous coronary perfusion with an empty, beating heart for 60 minutes at 35 degrees C.; III, hypothermic anoxic arrest (aortic occlusion) for 60 minutes with topical cold saline lavage (4 degrees C.); IV, anoxic arrest for 60 minutes at 35 degrees C. Subgroups of Groups III and IV received intracoronary perfusion with Ringer's lactate or Sacks' solution during aortic occlusion and were compared with those animals receiving no perfusion. Survival in Groups II and III was significantly better than in Group IV (82 and 92 per cent vs. 45 per cent). Coronary perfusion with Ringer's lactate or Sack's solution did not influence survival. The 23 survivors from all groups underwent left heart catheterization and LV cineangiography 5 months after operation. All three operative groups had significant elevation of LVEDP and depression of maximum developed dp/dt when compared with normal dogs. Ejection fraction was significantly depressed in Groups III and IV, and there was evidence of left ventricular hypokinesia and/or akinesia in all three operative groups. Differences in function between Groups II, III, and IV were not significant. The use of intracoronary solutions during anoxic arrest did not significantly influence these functional alterations. Evidence of subendocardial fibrosis was found in each of the operative groups, with the most marked changes found in the normothermic arrest group. Moderate fibrosis was present, however, in some survivors in both the continuous coronary perfusion and topical hypothermic arrest groups. These data indicate that although survival is greatly enhanced when coronary artery perfusion or topical hypothermia is used, neither method prevents chronic deterioration in ventricular function nor the development of subendocardial fibrosis.
J Thorac Cardiovasc Surg 1975 Dec
PMID:Long-term morphologic and hemodynamic evaluation of the left ventricle after cardiopulmonary bypass. A comparison of normothermic anoxic arrest, coronary artery perfusion, and profound topical cardiac hypothermia. 118 84

Depressed postoperative myocardial performance (low output syndrome) requiring inotropic drugs or balloon counterpulsation is due to subendocardial ischemic damage. Before July, 1972, we needed inotropic drugs in 30 to 52 per cent of 189 patients undergoing coronary revascularization or aortic or mitral valve replacement in whom we used ischemic arrest, profound topical hypothermia, and ventricular fibrillation. The mortality rate ranged from 10 to 17 per cent. Our experimental studies show that morbidity and death in such cases are caused by ischemic injury to the heart resulting from inadequate myocardial protection during bypass. Based on these experimental studies, we have, since July, 1972, employed the following principles clinically: (1) Maintain beating empty heart whenever possible; (2) maintain adequate coronary perfusion pressure (less than 80 mm. Hg); (3) avoid extreme hemodilution; (4) avoid ventricular fibrillation; (5) avoid prolonged hypothermic arrest, limiting ischemic periods to less than 15 minutes; (6) repay myocardial ischemic oxygen debt with total (vented) bypass; and (7) optimize DPTI/TTI (supply/demand ratio) pre- and postoperatively. These principles were followed in 189 consecutive operations, and postoperative inotropic drugs were needed in only 12. The principles were violated in 4 of the 12 patients (6 per cent), and 5 others had identifiable causes of myocardial depression; low output syndrome was unexplained in only 3 patients (1.7 per cent).
J Thorac Cardiovasc Surg 1975 Dec
PMID:Depressed postoperative cardiac performance. Prevention by adequate myocardial protection during cardiopulmonary bypass. 118 89

Eighty of 654 patients studied because of chest pain were found to have normal coronary arteriography. Fifty of these completed submaximal treadmill exercise studies. The purpose of this study was to determine whether treadmill electrocardiography could obviate the need for coronary arteriography in the evaluation of patients with undiagnosed chest pain. Of patients studied, 22% had typical angina pectoris, while 78% had atypical chest pain. The resting electrocardiogram was normal in 58% of patients, while 42% showed repolarization abnormalities. Submaximal treadmill testing was normal in 64%, incomplete in 12%, and demonstrated classic ischemic S-T depression in 24%. Our findings of 24% positive studies in patients with normal vessels and 12% incomplete tests suggest that stress electrocardiography may be of limited value in predicting the morphologic state of the coronary arteries in patients with undiagnosed chest pain.
Cathet Cardiovasc Diagn 1975
PMID:Exercise stress testing in patients with chest pain and normal coronary arteriography: with review of the literature. 122 21

Treadmill exercise test results were studied in 93 patients with chest pain who had received digitalis therapy or had nonspecific ST-T changes in the resting electrocardiogram. Results of the treadmill test were correlated with the findings of coronary angiography. A positive treadmill result was defined as horizontal or down-sloping ST segment depression greater than or equal to 1.0 mm. Of the 40 patients with no or insignificant coronary artery disease, 15 had taken digitalis; 4 of the 15 demonstrated a positive response on the treadmill test. Of the 53 patients with coronary artery disease, 21 had taken digitalis; 15 of the 21 displayed a positive response. Among the remaining 32 not on digitalis, 20 had a positive response. The specificity of the treadmill exercise test was 96% in patients with coronary artery disease not on digitalis and whose resting electrocardiogram showed nonspecific ST changes. The specificity of the treadmill test in patients who had received digitalis was 73%. Sensitivity was 63% and 71%, respectively. By utilizing more stringent criteria in the interpretation of the treadmill exercise test (greater than or equal to 1.5 mm ST depression), among the patients on digitalis only 6.7% (1/15) with normal coronary arteries and 48% (10/21) with coronary artery disease had a positive response. With the use of the latter criterion the test was specific in 93% (14/15) of the patients and is usually indicative of coronary artery disease.
Cathet Cardiovasc Diagn 1975
PMID:Treadmill exercise testing in the presence of digitals therapy or nonspecific ST-T changes: correlation with coronary angiography. 122 34

A heart model in dogs was developed to evaluate quantitatively the extent to which left ventricular chamber size could be reduced and yet retain residual mechanical function to perform adequately as a pump. In 9 animals placed on right heart bypass perfusion to control systemic flows; left ventricular performance was estimated from high-fidelity left ventricular pressure and aortic flowmeter recordings and from lateral plane left ventricular angiograms. Studies were made during unrestricted left ventricular filling at varying cardiac outputs and with inflation of a balloon in the left ventricular cavity at a physiological cardiac output. As compared with control data (cardiac output 1.4 L. per minute), balloon inflation to 18.7 ml. caused an increase in total left ventricular end-diastolic volume (from 35.4 to 44.3 ml., p less than 0.001) and left atrial pressure (from 7.8 to 21.2 mm. Hg; p less than 0.001); it also caused a reduction in left ventricular stroke work (from 12.5 to 8.1 Gm.-M., P LESS THAN 0.005) ANd max. dp/dt (from 2,487 to 1,320 mm. Hg per second, p less than 0.05). Importantly, left ventricular stroke volume was unchanged. When compared with preload augmentation (with the balloon deflated), the magnitude of depression of cardiac performance caused by balloon inflation was more fully appreciated (left ventricular stroke work, max. dp/dt, and ejection fraction reduced 69, 61, and 45 per cent, respectively). Even so, with appropriate compensations, principally by the Frank-Starling mechanism, up to 42 per cent of the left ventricular cavity volume could be functionally eliminated with retention of adequate mechanical performance. Such data may have implications regarding the extent of resections possible in patients undergoing surgery for left ventricular aneurysm.
J Thorac Cardiovasc Surg 1976 Feb
PMID:Functional reductions in left ventricular volume. Minimum chamber size consonant with effective hemodynamic performance. 124 44

Short-term results of aggressive surgical management were compared with results of medical management in forty-three patients with preinfarction angina admitted to the coronary-care unit (CCU) over an 18 month period. These patients were selected from 1,609 consecutive admissions to the CCU because they met strict criteria for preinfarction angina: severe chest pain at rest, ST-segment elevation or depression during pain which subsided rapidly after cessation of pain, and normal serum enzymes (CPK, SGOT, and LDH). Twenty-three patients had coronary angiography, done with operating room and pump standby. One patient, who had total occlusion of the left main coronary artery, died during the study. Twenty-one of the remaining patients were considered surgical candidates, and were treated immediately after angiography with 1 to 3 vein bypass grafts. There was one late postoperative death and, of the 20 survivors, 2 had ECG evidence of acute myocardial infarction and one had mild angina at time of discharge. In contrast, of the 21 patients treated medically, 13 sustained acute MI, resulting in 8 instances of congestive heart failure and 4 cases of ventricular fibrillation. Four patients died in cardiogenic shock. With the use of rigid criteria, a small subgroup of patients with variant angina at high risk of developing AMI has been identified and categorized as having preinfarction angina. Our experience suggests that aggressive surgery immediately following coronary angiography offers a lower incidence of MI, morbidity, and death than does medical management.
J Thorac Cardiovasc Surg 1976 Jan
PMID:Management of preinfarction angina. Evaluation and comparison of medical versus surgical therapy in 43 patients. 124 46

The electrophysiological effects of increasing molar concentrations of ajmaline were studied in isolated cardiac tissue, including sino-atrial node and Purkinje fibre. Ajmaline produced significant shortening of the plateau of Purkinje fibre action potential associated with marked depression of dV/dt and directly measured conduction velocity. A negative chronotropic effect was noted both in the sinus node and in spontaneously beating Purkinje fibres. Ajmaline's major electrophysiological effect appears to be depression of Purkinje fibre conduction velocity.
Cardiovasc Res 1976 Jan
PMID:Electrophysiological effects of ajmaline in isolated cardiac tissue. 125 92


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