A prospective clinical, scintigraphic, angiographic and functional evaluation of patients after inferior myocardial infarction with and without right ventricular dysfunction

To elucidate the functional and prognostic significance of right ventricular dysfunction after acute inferior wall myocardial infarction, 74 consecutive patients with inferior infarction were prospectively evaluated with gated equilibrium blood pool imaging at rest, submaximal exercise thallium-201 scintigraphy and coronary angiography before hospital discharge. In addition, symptom-limited stress thallium-201 scintigraphy was performed in 61 patients at 3 months, and all patients were followed up clinically for 23 +/- 15 months. Utilizing predetermined radionuclide angiographic criteria, 47 patients (Group I) had normal right ventricular function, 12 patients (Group II) had mild to moderate dysfunction and 15 patients (Group III) had severe right ventricular dysfunction. There were no significant differences among the groups with regard to age, history of prior myocardial infarction, peak creatine kinase values, maximal Killip functional class, number or type of in-hospital complications, left ventricular ejection fraction, prevalence of multivessel disease or the distribution and severity of disease affecting the infarct-related vessel. Exercise tolerance as assessed by treadmill time, blood pressure-heart rate product and peak work load in METS was comparable among the three groups, both before hospital discharge and at 3 month follow-up. No differences in indicators of exercise-induced ischemia were noted among the groups, including the prevalence of redistribution thallium-201 defects, ST segment depression or symptoms of chest pain. Finally, cardiac mortality, reinfarction rate and the incidence of medically refractory angina pectoris were similar in the three groups. Thus, right ventricular dysfunction after acute inferior wall myocardial infarction does not appear to limit exercise tolerance or identify a subgroup of patients at higher risk for recurrent cardiac events.     

Virtual Reality Rehabilitation With Functional Electrical Stimulation Improves Upper Extremity Function in Patients With Chronic Stroke: A Pilot Randomized Controlled Study

Objective

To compare virtual reality (VR) combined with functional electrical stimulation (FES) with cyclic FES for improving upper extremity function and health-related quality of life in patients with chronic stroke.

Maximal revascularization (reperfusion) in intact conscious dogs after 2 to 5 hours of coronary occlusion.

Acute infarction was produced in intact conscious dogs by inflating a previously implanted balloon cuff around the left anterior descending coronary artery was occluded in 26 control dogs and reperfused by deflating the balloon cuff after 2 hours of occlusion in 19 dogs (group II) and after 5 hours in 11 dogs (group III). Serial studies were performed and repeated after 48 hours and 7 days. All three groups revealed hemodynamic and metabolic deterioration with coronary occlusion and infarct production. Immediately after reperfusion, arrhythmias developed in groups II and III and persistent ventricular tachycardia was present 2 to 3 hours after reperfusion in 74 percent of animals in group II and 82 percent of those in group III compared with 6 percent and 13 percent incidence rates at corresponding times in control dogs. Q waves developed in 83 percent of animals in group II and 100 percent of those in group III but in only 12 and 27 percent of control animals at corresponding times. Hemodynamic deterioration was accelerated in the postreperfusion period in both groups II and III. Angiographic assessment revealed improvement in 42 percent of dogs in group II, but in none of those in group III after reperfusion. Myocardial oxygen extraction diminished to subnormal levels after reperfusion, indicating either reactive hyperemia or shunting effect. Mortality was not significantly influenced by reperfusion. Infarct size was more than 15 percent of ventricular mass in 92 percent of control dogs and in 100 percent of dogs in group III, but in only 50 percent of those in group II. The data indicate that reperfusion in conscious dogs representing early, noninvasive maximal revascularization under ideal circumstances fails to prevent deterioration or death; instead it hastens the development of arrhythmias and myocardial injury. Reperfusion, although deleterious in the first hours, can reduce infarct size if performed after 2 hours, but not after 5 hours, of occlusion.     

A method for large-scale, high-yield isolation of canine pancreatic islets of Langerhans

A modified collagenase digestion method is described for the isolation of large numbers of islets from the canine pancreas (approximately 3,500 islets/g). The islets isolated by this technique remained viable and released insulin in response to secretagogues after one week of maintenance in tissue culture. Islets isolated from a single donor pancreas were re-implanted into the spleen of the same animal made diabetic by subtotal pancreatectomy and two injections fo streptozotocin. Hyperglycemia was corrected in two dogs and decreased in a third dog followed for 30 days. The islet isolation method is described, therefore, provides a sufficiently large yield of viable islets from one donor pancreas to correct or improve diabetes in a recipient animal.     

Plasma antidiuretic hormone in acute respiratory failure

The role of antidiuretic hormone (ADH) in the pathogenesis of renal impaired water excretion in acute respiratory failure has not been clearly delineated. Plasma sodium concentration and plasma ADH levels (radioimmunoassay) were therefore serially measured in 13 patients with acute respiratory failure (10 with acute exacerbations of chronic lung disease and three with acute lung disease) and eight “control” patients admitted to the intensive care unit with suspected myocardial infarction. None of the patients had systemic hemodynamic, hepatic or renal dysfunction. ADH levels were significantly elevated in patients with acute respiratory failure (15.1 ± 5.2 pg/ml versus 5.7 ± 1.9 pg/ml, p < 0.05) when compared with levels in control patients. The elevated ADH levels occurred despite significantly lower plasma sodium concentration (133 ± 1 meq/liter versus 138 ± 2 meq/liter, p < 0.05) compared with control values. Moreover, markedly increased ADH values (range 1.1 to 13.0 pg/ml) were often encountered in patients with acute respiratory failure despite significant hyposmolality (263 to 275 mOsm/kg H₂O). This was not observed in any control patients. These results suggest that patients with acute respiratory failure are susceptible to water retention and hyposmolality due to nonosmotic release of antidiuretic hormone.     

Myocardial perfusion imaging in humans by contrast echocardiography using polygelin colloid solution

This study evaluated the myocardial contrast effect and safety of polygelin colloid solution selectively injected into the coronary arteries in 25 patients during two-dimensional echocardiography. Six patients (group I) had selective intracoronary injections of nonagitated and 19 (group II) of hand-agitated polygelin colloid solution. Myocardial contrast was seen on two-dimensional echocardiographic cross sections in three patients of group I and in all patients of group II; in 16 patients it was also seen on M-mode echocardiograms. The contrast effect lasted for 15 to 60 seconds. The intensity of myocardial opacification was not significantly influenced by the amount of polygelin colloid solution injected, heart rate or cardiac size. The total number of contrast-enhanced segments after right and left coronary artery injections delineated the entire cross-sectional area in any given view. None of the patients developed symptoms during or immediately after the injections. One patient had transient second degree atrioventricular block after a right coronary wedge injection, one patient showed a QRS axis shift and two others had transient T wave changes. There were no aortic blood pressure changes and no significant serum enzyme (creatine kinase [CK], CK-MB fraction, glutamic oxaloacetic transaminase) elevation or alterations of left ventricular function assessed echocardiographically. It is concluded that hand-agitated polygelin colloid solution is a useful and safe intracoronary contrast agent for delineating myocardial perfusion areas on two-dimensional echocardiography in humans.     

Effects of beta 1-selective and nonselective beta-adrenoceptor blockade during exercise conditioning in healthy adults

The interaction of beta 1-selective (cardioselective) and nonselective beta-adrenoceptor blockade with exercise conditioning was investigated in 30 healthy adult persons. A double-blind protocol was used and the effects of atenolol (100 mg/day), propranolol (80 mg twice daily), and placebo were studied by treadmill testing (Bruce protocol) before and after a 2-month supervised program of dynamic exercise. Exercise tolerance was assessed by time and work performed to exhaustion. Subjects who received propranolol, but not those who received atenolol or placebo, showed an acutely impaired exercise tolerance after drug administration but before training (-8 +/- 4%, p less than 0.05). All 3 groups showed significantly improved exercise capacity following training after drug treatment had been discontinued (atenolol, 22 +/- 6% improvement; propranolol, 13 +/- 6%; placebo, 10 +/- 3%). However, when tested while still receiving medication, subjects who received propranolol failed to show significant improvement in exercise capacity. In contrast, patients who received atenolol and placebo improved significantly. The data indicate that enhancement of maximal work capacity by exercise conditioning can occur despite administration of either beta 1-selective or nonselective beta-adrenoceptor antagonists. However, the fatiguing effects of propranolol that were evident when work performance during propranolol therapy was compared with work performance while not receiving propranolol before the training program persists after training and may limit the net improvement in work capacity induced by exercise conditioning compared with the pretraining state.     

Hyperosmolar hyperglycemic nonketotic syndrome. Report of 22 cases and brief review

In a series of 22 patients with the hyperosmolar hyperglycemic nonketotic syndrome managed during a five-year period in a community hospital setting, 21 patients were known to be diabetic and only six patients were in coma. The overall mortality was 36.3 percent, and seven of the eight deaths were explained by associated nonmetabolic causes. In this study, hyperosmolarity was not related to coma or to final outcome of treatment. Patients were managed with relatively small amounts of fluid, and the type of fluid used did not influence the final outcome.