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Query: UMLS:C0344329 (collapse)
 28,634 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Torsade de pointes may occur as a complication of amiodarone therapy. We report a patient receiving amiodarone who was resuscitated from cardiovascular collapse and documented ventricular fibrillation. At subsequent electrophysiology study, while the patient was taking amiodarone therapy, monophasic action potentials with early after depolarisations were recorded which were not present when the patient was restudied 6 weeks after discontinuation of amiodarone. Early after-depolarisations may be important in the genesis of polymorphic ventricular tachycardia complicating amiodarone therapy.
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PMID:Sudden cardiac death while taking amiodarone therapy: the role of abnormal repolarization. 178 40

Among patients with ventricular fibrillation outside hospital seen by our mobile coronary care unit between 1967 and 1988, 28 were aged less than 40 years (range 12-39, mean 28). Coronary artery disease was present in 11 (39 per cent) and was the most common single cause, although none of these patients was aged less than 28 years. Of 15 patients with cardiac disease, only four (27 per cent) had previously sought medical advice. Nineteen patients (68 per cent) collapsed without preceding symptoms. Survival to reach hospital was significantly associated with bystander cardiopulmonary resuscitation and early defibrillation. Eleven patients (39 per cent) survived to hospital discharge, of whom seven remain alive after 2 1/2 to 21 1/2 years, five without symptoms. Thus, as demonstrated for older patients, coronary artery disease is an important cause of sudden death in this age group, and bystander cardiopulmonary resuscitation and early defibrillation are important for survival. Most of these patients collapse without warning and are not already known to have cardiac disease.
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PMID:Out-of-hospital ventricular fibrillation in patients under the age of 40 years and the long-term prognosis. 180 Oct 55

This study demonstrates the effect of different denominators on the survival rate from out-of-hospital cardiac arrest. We retrospectively analyzed data from a cardiac arrest surveillance system in King County, Washington during the years 1976 to 1988, and calculated survival rates using eight different definitions of denominators. The eight survival rates ranged from 16% to 49% discharge from hospital. The denominator for the lowest survival rate included all cases of cardiac arrest for whom emergency medical services personnel started cardiopulmonary resuscitation. The denominator for the highest survival rate included: all cases of presumed cardiac etiology; first recorded rhythm was ventricular fibrillation; collapse witnessed; cardiopulmonary resuscitation started by bystanders within 4 minutes; and definitive care provided within 8 minutes. The definition of cases included in the denominator can dramatically effect the resultant survival rate. There must be national and international agreement about definitions of denominators for valid cross community comparisons.
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PMID:Numerators, denominators, and survival rates: reporting survival from out-of-hospital cardiac arrest. 193 Mar 93

Hemodynamic stress testing was performed in four calves with a chronically implanted left ventricular assist device consisting of a double-valved pump interposed between the left ventricular apex and the descending thoracic aorta. The device was powered either pneumatically (n = 1) or with a transcutaneous energy transmission system (n = 3). Hemodynamic evaluation (cardiac output and right and left ventricular and pulmonary and carotid artery pressures) was carried out at baseline and during all hemodynamically stressed states. Atrial pacing and ventricular pacing to a heart rate of 140 beats/min resulted in no significant change in right or left heart filling pressures or cardiac output. Preload reduction with nitroprusside or transient inferior vena cava balloon occlusion resulted in a marked decrease in left ventricular pressure with preservation of mean arterial pressure. Phenylephrine administration resulted in a marked rise in mean arterial pressure with no change in cardiac output or filling pressure. Induction of ventricular fibrillation resulted in a decrease of mean left ventricular pressure to 11 +/- 8 mm Hg, but mean arterial pressure was maintained at greater than or equal to 50 mm Hg. It is concluded that a multicomponent, implantable, electrically powered assist system is capable of maintaining a normal cardiac output under a wide range of loading conditions and chronotropic states. Although this device is clearly preload dependent, it is capable of maintaining normal systemic pressures during conditions of severe left ventricular dysfunction and circulatory collapse.
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PMID:Hemodynamic evaluation of a chronically implanted, electrically powered left ventricular assist system: responses to acute circulatory stress. 196 Mar 30

The author presents a retrospective and complex pathomorphological analysis in 152 autopsy cases. Death was caused by different forms of cardiomyopathies. Aim of the study to reveal the frequency of pathology, causes and mechanisms of death. The prevailing frequency of dilated cardiomyopathy was established--106 cases, 0.88%. Hypertrophic and restrictive forms--32 (0.27%) and 14 (0.12%) of cases. the dominating cause of death (42.7%) was chronic cardiac failure. Other death causes were as follows: thrombosis and embolism--17.8%; arrhythmic collapse--13.2%; ventricular fibrillation--9.9%; acute left-ventricular failure--8.6%; real cardiogenic shock--7.8% of all cases of cardiomyopathies.
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PMID:[The causes and mechanisms of death in cardiomyopathies]. 228 61

Ventricular fibrillation (VF) is the first recorded arrhythmia in 75% of patients who have a sudden cardiovascular collapse. Rarely (1%) does sustained ventricular tachycardia (VT) alone cause collapse and unconsciousness. Whether all VF begins as VT is unknown. Early application of cardiopulmonary resuscitation and rapid defibrillation are essential to ensure survival and satisfactory neurologic recovery. During the last 2 years in Seattle, the initial resuscitation rate for VF was 269 of 447 patients (60%), with 114 of 447 patients (26%) surviving long-term. Survivors of VF have a high overall risk of recurrent VF, with many univariate risk factors identified: evidence of poor left ventricular function (history of congestive heart failure, prior myocardial infarction [MI] or low ejection fraction), extensive coronary artery disease, absence of a new MI (either Q wave or non-Q wave) with VF, male gender, advanced age, complex or high-frequency ventricular ectopy on Holter recording, inducibility at electrophysiologic study, exercise-induced angina or hypotension, and smoking. Classification of cardiac deaths as arrhythmic or nonarrhythmic is important in interpreting the therapeutic response. However, because many patients have chronic symptoms, timing of the onset of a new event is difficult. Furthermore, accurate timing of an event does not guarantee correct classification. Sudden death is not necessarily arrhythmic, nor is all arrhythmic death sudden. Total cardiac mortality may be a simpler and more relevant end point to measure the overall effect of antiarrhythmic therapy.
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PMID:Sudden arrhythmic cardiac death--mechanisms, resuscitation and classification: the Seattle perspective. 240 96

Acute fluoride poisoning is associated with sudden cardiac death by an unknown mechanism. Because F- binds to Ca2+ to cause marked hypocalcemia, lowered serum Ca2+ concentrations have been thought to be a major underlying factor in the ventricular irritability of F(-)-toxic patients. However, correction of the hypocalcemia does not prevent sudden death. Paradoxically, while decreasing extracellular Ca2+ levels, in vitro studies have shown F- increases intracellular Ca2+, which is thought to trigger Ca2+-dependent K+ channels and produce a K+ efflux. The K+ efflux may be important clinically, as patients with F- overdose can exhibit hyperkalemia shortly before cardiovascular collapse. In erythrocyte suspensions, we found that propranolol, which increases the sensitivity of the Ca2+-dependent K+ channels, exacerbates the efflux, and quinidine, which blocks the channel, prevents the efflux. In six dogs, 35 mg/kg of sodium fluoride given intravenously produced intractable ventricular fibrillation within 140 minutes. Four dogs given 200 mg of quinidine sulfate with the sodium fluoride developed no ventricular arrhythmias. The data indicate that F--induced hyperkalemia is important in sudden cardiac death following acute fluoride toxicity and that this hyperkalemia is mediated by Ca2+-dependent K+ channels.
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PMID:Fluoride-induced hyperkalemia: the role of Ca2+-dependent K+ channels. 244 37

This study evaluated the systemic toxicity, arrhythmogenicity, and mode of death of convulsant and supraconvulsant doses of lidocaine, bupivacaine, and ropivacaine. Experiments in awake dogs were designed to mimic the clinical situation of an accidental intravenous (IV) injection of local anesthetics. On the first experimental day, lidocaine (8 mg.kg-1.min-1), bupivacaine (2 mg.kg-1.min-1), and ropivacaine (2 mg.kg-1.min-1) were infused intravenously until seizures occurred (n = 6 for each group). The average dose and arterial plasma concentration at seizure onset was 20.8 +/- 4.0 mg/kg and 47.2 +/- 5.4 micrograms/mL for lidocaine, 4.31 +/- 0.36 mg/kg and 18.0 +/- 2.7 micrograms/mL for bupivacaine, and 4.88 +/- 0.47 mg/kg and 11.4 +/- 0.9 micrograms/mL for ropivacaine. The margin of safety between the convulsive and lethal doses was determined by administering two times the convulsive dose 24 h later. Two dogs given lidocaine died because of progressive hypotension, respiratory arrest, and finally cardiovascular collapse with an average peak plasma concentration (Cmax) of 469 micrograms/mL. No ventricular arrhythmias were observed in this group. Ventricular arrhythmias occurred in five of six dogs receiving bupivacaine. Four animals died because of hypotension, respiratory arrest, and cardiovascular collapse. One additional animal died because of ventricular fibrillation. The Cmax for bupivacaine was 70.1 +/- 14.6 micrograms/mL in nonsurvivors. In the ropivacaine group one animal died because of hypotension, respiratory arrest, and cardiovascular collapse (Cmax = 72.4 micrograms/mL). A surviving dog had transient premature ventricular contractions. Twenty-four hours later three times the convulsive dose was administered to the survivors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Comparative systemic toxicity of convulsant and supraconvulsant doses of intravenous ropivacaine, bupivacaine, and lidocaine in the conscious dog. 251 82

Four hundred sixty-three cases of cardiac arrest treated in the pre-hospital setting by advanced life support (ALS) or paramedic units in Monroe County, New York, were evaluated using Eisenberg's criteria, which define factors known to be critical for successful resuscitation. Forty-eight patients met the criteria of witnessed collapse and cardiopulmonary resuscitation (CPR) within four minutes and ALS within ten minutes, with the initial rhythm of ventricular fibrillation or pulseless ventricular tachycardia. Of these, 16 (33%) patients were discharged from the hospital. This compares to 12 of 415 (3%) patients discharged who did not meet the criteria. Of the 171 patients who suffered witnessed arrests of cardiac origin, 20 survived to be discharged. This represents a successful resuscitation rate of 12%. These percentages are within the range noted for other ALS services in the United States.
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PMID:Resuscitation of cardiac arrest victims by advanced life support units in Monroe County, New York. 259 61

Ambulance staff with advanced training in cardiopulmonary resuscitation and equipped with monitor/defibrillators were used as the initial responders to collapse calls within a medically based prehospital coronary care system. During 21 months, in a population of approximately 120,000, ambulance staff successfully resuscitated six patients from ventricular fibrillation; there were four long term survivors. The median response time of emergency ambulances to collapse calls was eight minutes compared with 20 minutes for the medically manned mobile coronary care unit. None of the patients resuscitated by ambulance staff would have survived if they had been dependent on the mobile coronary care unit acting alone. Nineteen other patients with important arrhythmias were referred for earlier medical management which in some cases may have saved lives. An additional eight long term survivors of out of hospital ventricular fibrillation were resuscitated by medical staff. The integration of paramedical with medical prehospital coronary care improved survival after out of hospital cardiac arrest.
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PMID:Integration of ambulance staff trained in cardiopulmonary resuscitation with a medical team providing prehospital coronary care. 260 56


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