Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(I.) Toxicity of ionic coronary arteriography contrast media has been shown to depend on their cationic and anionic composition and their osmolality. Using a right coronary injection technique in the dog, the authors have shown a relationship between toxicity as manifested by occurrence of ventricular fibrillation and the presence of calcium binders in the contrast media. Sodium citrate and EDTA have been identified as the specific agents in certain contrast media that significantly increase the incidence of fibrillation in laboratory experiments. (II.) A deleterious synergism between water-soluble angiographic and urographic media and digitalis compounds has now been demonstrated, based on mortality studies (LD50) using bolus intravenous injections in white mice. The testing of a number of other classes of drugs for a similar effect has shown thus far that only the digitalis class exhibits this synergism. Surprisingly, the nonionic contrast medium, metrizamide, has been shown to have a greater synergistic effect with digitalis drugs than diatrizoate ionic media. (III.) In dog experiments under Nembutal anesthesia in which aortic flow, pulmonary artery and vein pressures, systemic arterial pressure, and EKG were monitored, left atrial pressure increases as soon as or before pulmonary artery pressure rises, even at low doses of ionic contrast media administered intravenously. This may indicate 1) flow to the left heart increases dramatically, or 2) there is a very early myocardial depression. The significance of the above findings and application to clinical practice will be discussed.
 ...
PMID:Cardiovascular radiology. Possible factors in intravascular contrast media toxicity. 720 28

1 The antidysrhythmic and haemodynamic effects of the aminosteroid, Org 6001, were studied in the rat anaesthetized with pentobarbitone. Mexiletine was used for comparison. 2 Both Org 6001 (2--10 mg/kg) and mexiletine (1 mg/kg) given intravenously antagonized the development of dysrhythmias evoked by acute coronary artery ligation in rats. 3 In antidysrhythmic doses, Org 6001 and mexiletine exerted only moderate and transient hypotension and depression of cardiac contractility (assessed from LV dP/dtmax). Org 6001 did, however, induce a more sustained bradycardia. 4 Effective oral doses of Org 6001 (20--100 mg/kg) were similar to those of mexiletine, disopyramide and propafenone. 5 Oral Org 6001 (100 mg/kg) was effective for 18 h whereas mexiletine (100 mg/kg) failed to protect against evoked dysrhythmias 3 h after dosing. 6 Org 6001 and mexiletine differed in their actions on ventricular fibrillation threshold (VFT). Org 6001 (100 mg/kg orally 12 h before ligation) prevented the decrease in VFT produced by coronary ligation whereas mexiletine (100 mg/kg orally) had no effect. When administered intravenously, mexiletine (but not ORg 6001) increased VFT in normal ventricular muscle.
 ...
PMID:Comparative antidysrhythmic and haemodynamic effects of orally or intravenously administered mexiletine and ORG 6001 in the anaesthetized rat. 731 87

This report describes a case of a patient with a history of classical angina of effort which developed into an unstable progressive syndrome. A 42-year-old-woman was admitted to the hospital because of resting angina pectoris. Examination revealed signs of septal subepicardial ischemia in the resting electrocardiogram and a positive ergometric test with marked depression of the S-T segment. Hemodynamic studies showed in the ventriculogram a clearly defined area of hypokinesis on the anterolateral segment of the ventricle and the coronariography revealed normal vessels. During exercise the patient developed anginal pain and an elevation of the S-T segment in a lead II electrocardiogram. During the pain episode, selective left and right coronariographies showed the presence of a severe spasm in the first portion of the anterior descending branch. In the course of one of the injections the patient developed ventricular fibrillation, this was reverted with a 400 watts/sec shock. The patient was discharged from the hospital a few days after and has been successfully treated with nitrates and calcium blocking agents. This case represents the first time that a coronary spasm in normal vessels has been adequately documented by us.
 ...
PMID:[Exercise-induced coronary artery spasm. Angiographic demonstration and results of medical treatment]. 732 47

General anesthetic agents can be divided on the basis of whether or not they "sensitize" the heart to the arrhythmogenic actions of catecholamines. There appear to be two separate means by which the catecholamines cause ventricular arrhythmias during anesthesia: one is related to a reduction in supraventricular driving rate caused both directly by the anesthetic and reflexly in response to the pressor effect of catecholamine injection; the other action (favoring ventricular fibrillation) is caused by direct anesthetic depression of the intraventricular conducting system. Of the anesthetics used today, halothane has the most pronounced cardiac sensitizing action. The same anesthetics can also be divided according to whether or not they stimulate sympathetic nervous system activity. Those that do (e.g., diethyl ether) abolish the barostatic reflexes. Those that do not (e.g. halothane) reset the barostatic reflexes to favor a reduced level of arterial pressure; they also tend to cause a reduction in sympathetic nervous activity efferent to the heart. Parasympathetic nervous actions are relatively insignificant. All general anesthetics cause myocardial depression at all concentrations that are clinically useful. The mechanism appears to involve a reduction in the Ca2+ available to the contractile elements. Exactly how anesthetics do this is unclear, but these drugs appear to decrease both the Ca2+ influx across the plasma membrane and the Ca2+ content of the sarcoplasmic reticulum.
 ...
PMID:Effects of anesthetics on the heart. 736 54

Holter system electrocardiograms were recorded for 617 patients who were treated at the Department of Cardiology, Tokai University Hospital. In cases of arrhythmia, ventricular premature contraction (VPC) was the most predominant, in 291 cases (69%) out of 423 with arrhythmia, followed by 59 (14%) with supraventricular premature contraction (SVPC), 23 (5.4%) with paroxysmal atrial tachycardia, 17 (4%) with second degree A-V block and 10 (2.3%) with transient atrial fibrillation (AF). In addition, nine (2.1%) cases of ventricular tachycardia (VT), one (0.2%) of transient ventricular fibrillation (VF) and one (0.2%) of third degree A-V block were found in particularly severe arrhythmia cases. Six out of nine cases of VT were cases of acute myocardial infarction (AMI) and all died suddenly while in the hospital or after discharge. Mild or moderate changes in ST-T were often observed even in normal subjects. Of the 617 cases, only 18 (2.9%) showed a significant elevation or depression of ST. Among these, three definitely had variant angina pectoris (Prinzmetal type). The above results indicate Holter EKGs are very useful for the diagnosis of arrhythmia and can also be used as a means of evaluating the prognosis in some cases, but there still are some problems in connection with its use for the diagnosis of ischemic heart disease except for the diagnosis of variant angina pectoris.
 ...
PMID:Holter system electrocardiographic studies on 617 cases. 738 65

1. Lignocaine (1 mg kg-1 min-1 infused intravenously for 30 min) greatly reduced the incidence of ventricular ectopic beats that resulted from acute coronary artery ligation in anaesthetized greyhound dogs. However, the incidence of ventricular fibrillation was only slightly reduced by this treatment which caused significant myocardial depression. 2. There is no good evidence from this study that lignocaine is a particularly effective prophylactic in acute myocardial infarction.
 ...
PMID:Prophylactic lignocaine and early post-coronary artery occlusion dysrhythmias in anaesthetized greyhounds. 747 Jul 64

The hemodynamic profile and antiarrhythmic properties of pirsidomine, a nitric oxide donor, were examined in pigs. Intravenous administration of pirsidomine (1 mg/kg) to chloralose-anesthetized open-chest pigs resulted in a decreased afterload, and a reduced myocardial contractility and myocardial oxygen consumption (assessed by rate-pressure product), with no alterations in heart rate. After induction of regional myocardial ischemia by occlusion of the left anterior descending coronary artery, pigs given pirsidomine experienced fewer ventricular ectopic beats (119 +/- 29) than control animals did (217 +/- 53; p < 0.05), seen primarily as a reduction in the number of couplets and triplets. Although the incidence of ventricular fibrillation was unaffected by pirsidomine, the time to onset of this arrhythmia was significantly prolonged by this intervention (21.3 +/- 0.9 min versus 16.1 +/- 2.5 min in controls; p < 0.05). Furthermore, the ST-segment depression seen throughout the 30-min occlusion period in controls was not sustained beyond 5 min postocclusion in pirsidomine-treated pigs. Taken together, and in the absence of an ex vivo antiplatelet effect with this dose of pirsidomine, these results suggest that the antiarrhythmic effect of pirsidomine lies in its hemodynamic effects, resulting in a reduction of ischemia. The ex vivo effect of pirsidomine on free radical generation from isolated leukocytes was also investigated. Luminol-enhanced chemiluminescence produced by leukocytes in response to phorbol myristate acetate was markedly depressed in cells isolated from blood withdrawn after administration of pirsidomine, compared with cells tested before drug administration.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Pirsidomine, a novel nitric oxide donor, suppresses ischemic arrhythmias in anesthetized pigs. 750 68

Low values of heart rate variability (HRV, a marker of vagal tone) and baroreflex sensitivity (BRS, a marker of vagal reflexes) identify patients at higher risk soon after myocardial infarction (MI). However, it is still unknown whether HRV and BRS correlate with malignant arrhythmias after the recovery from the transient post-MI autonomic disturbance. This study assessed whether HRV and BRS would differ in patients with malignant ventricular arrhythmias occurring long after MI compared with those in a control population. Twenty-eight patients entered the study: 14 patients with episodes of sustained ventricular tachycardia or ventricular fibrillation occurring more than 1 year after MI, age (mean +/- SEM) 64 +/- 2 years, and left ventricular ejection fraction 34% +/- 3% (VT/VF group) were compared with 14 similar patients with no ventricular tachycardia (control group). Mean RR interval was not different in the two groups (844 +/- 37 msec in VT/VF and 892 +/- 24 msec in control group). Also, no difference was found in any time- or frequency-domain measure of heart rate variability. However, patients in the VT/VF group had a significantly lower baroreflex sensitivity compared with patients in the control group (4.2 +/- 0.5 vs 8.0 +/- 1.1 msec/mm Hg, p = 0.008). Thus BRS but not HRV was reduced in patients with life-threatening ventricular arrhythmias occurring long after MI. A persistent depression of vagal reflexes may play a role in the occurrence of malignant arrhythmias, and analysis of BRS may potentially be helpful in the identification of patients at high risk long after myocardial infarction.
 ...
PMID:Baroreflex sensitivity, but not heart rate variability, is reduced in patients with life-threatening ventricular arrhythmias long after myocardial infarction. 766 Oct 63

Patients undergoing vascular surgery are at high risk of developing cardiac events in the perioperative period. The aim of the study was the evaluation of the predictive accuracy of transesophageal atrial pacing (TAP) in identifying patients at higher risk of developing major cardiac events (cardiac death, acute myocardial infarction, unstable angina, heart failure and sustained ventricular tachyarrhythmias). We studied 96 consecutive patients, 80 males and 16 females, median age 63, requiring arterial surgery (aortofemoral or aortoiliac bypass and thromboendoarterectomy, abdominal aneurysm resection and extracranial carotid thromboendoaterectomy). TAP was performed without cardioactive drugs in all patients, but one. After surgery CK and CKMB serial assessment and ECG recording were performed daily until the seventh postoperative day. Preoperatively all patients were admitted to the Intensive Care Unit and submitted to haemodynamic monitoring with Swan-Ganz catheter at least for 72 hours. Three patients did not undergo surgery because of severe ST depression during TAP. Thus, 93 patients (96.8% of the series) were the subject of this report. In the postoperative period only two events (2.1% of the patients) were recorded, one relapsing acute myocardial infarction and one ventricular fibrillation, both in patients with negative TAP. No death occurred. Our study shows a very low prevalence of major cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Evaluation of cardiac risk in patients undergoing major vascular surgery. Usefulness and limitations of transesophageal atrial pacing]. 788 92

Extracellular potassium rises rapidly during myocardial ischaemia, correlating with the onset of ventricular arrhythmias. The extracellular accumulation of potassium can induce abnormalities in both impulse conduction and impulse generation. Inhomogeneities of potassium conductance will elicit regional differences in action potential duration and repolarisation. The resulting spatial dispersion of refractory period will allow for fragmentation of impulse conduction on ensuing beats, the formation of irregular reentrant pathways and ventricular fibrillation. In a similar manner, the spread of injury current from the ischaemic tissue to surrounding normal tissue can trigger extrasystoles (depolarisation induced automaticity). It has been hypothesised that the activation of the ATP sensitive potassium channel contributes significantly to reductions in action potential duration and increases in extracellular potassium accumulation during myocardial ischaemia. ATP sensitive potassium channel antagonists prevent ischaemically induced reductions in action potential duration and the dispersion of refractory period but may induce oscillatory afterpotentials under some conditions (for example, calcium overload). In contrast, potassium channel agonists enhance the dispersion of refractory period ischaemia, which promotes the formation of re-entrant arrhythmias. The pharmacological modulation of the ATP sensitive potassium channels could therefore offer a novel approach for the management of cardiac arrhythmias in patients with ischaemic heart disease. In general, channel antagonists prevent ventricular fibrillation, while high (hypotensive) doses of channel agonists can induce malignant arrhythmias during ischaemia in animal models. However, recent evidence also suggests that potassium channel agonists may promote a better preservation of myocardial mechanical performance during reperfusion while ATP sensitive potassium channel antagonists exacerbate mechanical depression during ischaemia in experimental models.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Role of ATP sensitive potassium channel in extracellular potassium accumulation and cardiac arrhythmias during myocardial ischaemia. 792 77


<< Previous 1 2 3 4 5 6 7 8 9 10