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Biomedical subjects

L A Cobb

Publications and source records attributed to L A Cobb.

At least 91 records · Page 5Linked to original sources
PubMed1981

Comparison of bretylium tosylate and lidocaine in management of out of hospital ventricular fibrillation: a randomized clinical trial.

Bretylium tosylate was compared with lidocaine hydrochloride as initial drug therapy in 146 victims of out of hospital ventricular fibrillation in a randomized blinded trial. An organized rhythm was achieved in 89 and 93 percent and a stable perfusing rhythm in 58 and 60 percent of the patients who received bretylium and lidocaine, respectively. After initiation of advanced life support, an organized rhythm was first established after an average of 10.4 minutes and 10.6 minutes in the two respective groups, requiring an average of 2.8 defibrillatory shocks in those who received bretylium and 2.4 in the lidocaine-treated patients. Comparable numbers of patients were discharged from the hospital: 34 percent of those given bretylium and 26 percent of the patients whose initial therapy was lidocaine. No instance of chemical defibrillation was observed with either drug. In this study, bretylium afforded neither significant advantage nor disadvantage compared with lidocaine in the initial management of ventricular fibrillation.

Bretylium Compounds↗
PubMed1981

Visualization of cardiac valve motion in man during external chest compression using two-dimensional echocardiography. Implications regarding the mechanism of blood flow.

Five patients who underwent cardiopulmonary resuscitation (CPR) were studied by two-dimensional echocardiography to assess valve motion. The mitral valve remained open throughout the entire compression-release cycle of CPR. The aortic valve opened during the compression phase of CPR and closed during the release phase. The pulmonic valve moved toward the closed position during the compression phase and the valve leaflets opened during release. Tricuspid valve leaflets never completely apposed, even during maximum chest compression, and they were widely open during release. Left ventricular dimensions did not change appreciably during CPR. These findings support the theory that forward blood flow during CPR depends on a generalized increase in intrathoracic pressure and not on direct compression of the heart itself. The left heart appears to act as a conduit for passage of blood, and mitral valve closure is not necessary for forward blood flow during CPR.

Adult↗
PubMed1980

Treatment of out-of-hospital cardiac arrests with rapid defibrillation by emergency medical technicians.

The survival rate for patients with out-of-hospital cardiac arrest is low in communities where emergency service is provided solely by emergency medical technicians. We trained such technicians in a suburban community of 79,000 to recognize and treat out-of-hospital ventricular fibrillation with up to three defibrillatory shocks without the use of medications or special airway protection. Outcomes from cardiac arrest due to underlying heart disease were determined during two periods: two years with standard care by emergency medical technicians and one year with defibrillator-trained technicians. During the period with standard care, four of 100 patients with cardiac arrest were resuscitated and discharged alive from the hospital, as compared with 10 of 54 patients during the period with defibrillator-trained technicians (P less than 0.01). In 12 of 38 patients with ventricular fibrillation, a stable perfusing cardiac rhythm followed defibrillatory shocks given by defibrillator technicians. The enhanced survival after cardiac arrest is encouraging, and further trials of defibrillation by emergency medical technicians are warranted.

Aged↗
PubMed1980

Management of out-of-hospital cardiac arrest. Failure of basic emergency medical technician services.

Survival after out-of-hospital cardiac arrest treated by emergency medical technicians (EMTs) with basic life support was studied in four communities with a combined population of 380,000. During a two-year period, 18 (6%) of 321 patients with cardiac arrest were resuscitated and ultimately discharged from the hospital. This figure is compared with 55 (22%) of 253 discharged in adjacent suburban communities with paramedic services. The evident factor accounting for the difference in survival rates was the time from collapse to receiving definitive care (advanced cardiac life support)--26 minutes in the EMT area compared to 7.8 minutes in the paramedic area.

Aged↗
PubMed1979

Bystander-initiated cardiopulmonary resuscitation in the management of ventricular fibrillation.

We assessed the influence of bystander-initiated cardiopulmonary resuscitation upon outcome in 316 consecutive patients treated for out-of-hospital ventricular fibrillation. Of 109 patients who received bystander-initiated cardiopulmonary resuscitation, 47 (43%) were ultimately discharged home. Of 207 patients for whom resuscitation was delayed until arrival of fire department personnel, 43 (21%) survived (P less than 0.001). Improved survival was largely due to a reduction in subsequent hospital mortality rather than to a higher rate of initially effective resuscitation. In a separate analysis of 118 patients treated at a single institution after resuscitation, the reduced hospital mortality reflected a decrease in deaths due to shock and to anoxic encephalopathy. In addition, neurologic dysfunction was significantly less common if bystanders had initiated cardiopulmonary resuscitation. Bystander participation in cardiopulmonary resuscitation represents an important adjunct to a rapid-response emergency care system.

Consciousness↗
PubMed1979

Platelet survival in patients previously resuscitated from out-of-hospital ventricular fibrillation.

Platelet survival times were measured in 11 ambulatory patients within 5 to 21 months of out-of-hospital ventricular fibrillation unassociated with acute myocardial infarction. The mean platelet survival time of 7.7 +/- 2.1 days was shortened when compared with 28 normal controls of similar age (9.0 +/- 1.0 days, p less than 0.03) but not different from 56 other patients with stable angina pectoris (6.85 +/- 1.81 days, p less than 0.2). One patient with a near normal survival time of 7.5 days experienced recurrent ventricular fibrillation without associated acute myocardial infarction 1 month following the platelet survival study. Although one platelet inhibitory agent, sulfinpyrazone, may lower the incidence of sudden cardiac death following acute myocardial infarction, the shortened platelet survival time in the group of patients experiencing out-of-hospital ventricular fibrillation did not distinguish them from others with coronary artery disease.

Aged↗
PubMed1978

Repolarization abnormalities in survivors of out-of-hospital ventricular fibrillation.

Survivors of out-of-hospital ventricular fibrillation (VF) are at high risk for recurrent VF, probably reflecting continued myocardial electrical instability. In this study 12-lead ECGs of 125 VF survivors with coronary heart disease were examined and compared to those of 98 ambulatory post-MI patients. The study was part of an effort to define clinical identifiers of patients likely to develop sudden cardiac death. Ventricular fibrillation survivors were commonly had premature ventricular complexes (PVCs):30% versus 13% (P less than 0.01). In addition, ECGs of VF survivors showed a significantly greater prevalence of ST-segment depression (46% versus 10%), T wave flattening (52% versus 26%), and QTc prolongation (35% versus 18%). It is proposed that these repolarization abnormalities represent asynchronous repolarization, which together with frequent PVCs, may set the stage for re-entrant ventricular dysrhythmias and ultimately VF. It is also possible that repolarization abnormalities together with premature ventricular contractions might serve as markers of patients with coronary heart disease who are at increased risk for sudden cardiac death.

Aged↗
PubMed1977

Myocardial imaging and radionuclide angiography in survivors of sudden cardiac death due to to ventricular fibrillation: preliminary report.

Twenty-one long-term survivors of out of hospital sudden cardiac death due to ventricular fibrillation underwent radionuclide angiography and myocardial imaging with thallium-201. In 13 patients images were obtained at rest and after maximal treadmill exercise; 11 of these 13 (85 percent) had an image defect in one or both studies. Eleven of the 21 patients (52 percent) had a defect in the image obtained at rest. The magnitude of myocardial image defects was typically great; some patients had an image abnormality without other clinical evidence (angina, S-T depression) of ischemia. The mean ejection fraction, assessed in 16 patients with radionuclide angiography, was 0.41 +/- 0.15 (standard deviation); in 5 of the 16 ejection fraction was normal (more than 0.50) and in 3 it was severely abnormal (less than 0.25). Thus, noninvasive radionuclide studies defined a broad spectrum of ischemic and ventriculographic abnormalities in survivors of sudden cardiac death. Further application of these noninvasive studies may identify those at high risk.

Adult↗
PubMed1976

A rapid response system for out-of-hospital cardiac emergencies.

We have reviewed several aspects of our initial 5 years' experience with an out-of-hospital emergency medical care system. This system is stratified and provides for rapid primary response and, when indicated, secondary response by specially trained paramedical personnel. Patient care is physician-supervised and closely monitored. Although considerable attention has been directed to acute complications of ischemic heart disease, particularly the problem of sudden cardiac death, the system is broadly based and responds to all medical emergencies. We are impressed with the ability of nonphysicians to acquire certain medical skills and judgment. Indeed, the effectiveness of this system is largely dependent on paramedical personnel. Such systems of prehospital emergency medical care will probably have an impact greater than that of hospital coronary care units in reducing the mortality from ischemic heart disease.

Coronary Care Units↗
PubMed1976

Angiographic findigs and prognostic indicators in patients resuscitated from sudden cardiac death.

Sixty-four patients with coronary artery disease (CAD) who had been resuscitated from out-of-hospital ventricular fibrillation (VF) underwent cardiac catheterization and angiography. The majority (72%) had a previous history of cardiovascular disease; in the remaining 28%, VF was the first manifestation of CAD. Advanced coronary atherosclerosis was a common finding; 94% of the patients had severe stenoses (70% or greater diameter narrowing) in one or more of the major coronary arteries, and most (70%) had ventricular wall contraction abnormalities. In over half of the patients, coronary anatomy was potentially suitable for complete revascularization. During an average follow-up period of 20.4 months, fourteen of the 64 patients developed a second episode of VF and/or died suddenly (VF/SD). In an attempt to identify characteristics which might be of prognostic value, the clinical, hemodynamic, and angiographic characteristics of this group were compared to those patients who had a single episode of VF and survived during follow-up. Patients who developed recurrent VF/SD had more triple vessel CAD (P less than 0.01), lower ejection fractions (P less than 0.05), and far more severe abnormalities of left ventricular contraction (P less than 0.001). These results indicate that angiographic findings can identify individuals at high risk for recurrent VF and also suggest that myocardial scarring may be an important factor in the initiation of ventricular fibrillation and in its recurrence.

Adult↗
PubMed1975

Recurrent ventricular fibrillation and modes of death in survivors of out-of-hospital ventricular fibrillation.

We examined the causes of death in patients previously resuscitated from out-of-hospital ventricular fibrillation. In 51 months, 234 patients were sucessfully resuscitated, hospitalized and discharged home. During follow-up observation, 89 episodes of recurrent ventricular fibrillation or death (or both) occurred, 64 of which (72 per cent) were unexpected, out-of-hospital circulatory arrests. Ventricular fibrillation occurred in 77 per cent of the 44 episodes in which the electrocardiogram was observed. Ten patients survived one or more episodes of recurrent ventricular fibrillation. Median time to recurrent ciruclatory arrest was 20 weeks after the preceding episode. Prodromal symptoms were infrequent, and activity levels were generally low at the time of cardiac arrest. Recurrent ventricular fibrillation of sudden death (or both) occurred predominantly when the initial episode was not associated with acute myocardial infarction. Patients resuscitated from ventricular fibrillation are susceptible to early recurrence, probably reflecting continuing myocardial electrical instability.

Adult↗