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Biomedical subjects

I Wiener

Publications and source records attributed to I Wiener.

89 records · Page 5Linked to original sources
PubMed1981

Release of cholecystokinin in man: correlation of blood levels with gallbladder contraction.

Although it is generally assumed that release of cholecystokinin (CCK) is the chief mechanism by which a fatty meal causes contraction of the gallbladder, measured release of CCK and gallbladder contraction have never been correlated. We have achieved this correlation in eight adult male volunteers, by means of a specific radioimmunoassay for CCK and by ultrasonographic imaging of the gallbladder. This study validates our CCK radioimmunoassay and correlates measured concentrations of CCK with changes in gallbladder size measured by ultrasonographic examination. Basal concentrations of CCK (82.6 +/- 10.4 pg/ml) rose significantly to a maximum of 411.1 +/- 79.9 pg/ml at 16 minutes after intraduodenal instillation of medium-chain triglyceride (Lipomul). Mean basal volume of the gallbladder was 34.6 cm3; maximum reduction of gallbladder volume (to one-third of original) was achieved at 18 minutes. Elevated CCK concentrations began to fall toward basal, and the gallbladder began to refill at 25 minutes. Results obtained after oral ingestion of Lipomul provide similar results. Linear regression analysis demonstrated excellent correlation between concentrations of CCK and gallbladder size during both contraction and relaxation phases. Future study of this correlation may be useful in patients with manifest dysfunction of the gallbladder, as well as in individuals known to be at risk of gallbladder disease.

Adult↗
PubMed1981

Spontaneous termination of circus movement tachycardia using an atrioventricular accessory pathway: incidence, site of block and mechanisms.

The incidence, mechanisms and sites of block of spontaneous termination of circus movement tachycardia (CMT) using an atrioventricular accessory pathway (AP) were analyzed in 24 consecutive patients (17 with Wolff-Parkinson-White syndrome and seven with a concealed AP) who were not receiving antiarrhythmic drugs. Spontaneous termination of tachycardia occurred in 10 patients (105 episodes). A reduced "safety margin" of tachycardia was the only factor that was significantly more common in the patients who manifested spontaneous termination (p less than 0.01). The site of spontaneous block was located in the AP in six patients (50 episodes), atrioventricular node (AVN) in six patients (37 episodes) and His-Purkinje system (HPS) in three patients (18 episodes). At least 14 mechanisms leading to block in the tachycardia circuit were identified. Labile conduction during tachycardia occurred at multiple sites (AVN, His bundle, bundle branches, and AP). Analysis of the duration of tachycardia before spontaneous termination showed a characteristic time pattern for block at each site, consistent with the autonomic and electrophysiologic changes that occur after induction of tachycardia. Spontaneous termination of CMT using an AP is a common phenomenon. Many mechanisms are involved, which are often complex and dependent on interplay of the electrophysiologic characteristics of the components of the tachycardia circuit.

Adolescent↗
PubMed1980

Initiation and termination of ventricular tachycardia by supraventricular stimuli. Incidence and electrophysiologic determinants as observed during programmed stimulation of the heart.

In 7 of 43 patients in whom a sustained ventricular tachycardia could be induced during programmed electrical stimulation by a single ventricular premature stimulus, an identical tachycardia could also be initiated by a single atrial premature stimulus. This phenomenon was observed only in those patients in whom the ventricular tachycardia could be induced by a single ventricular extrastimulus having a prematurity index (ratio between the longst ventricular premature stimulus interval resulting in tachycardia and th duration of the basic cycle length of the paced ventricular rhythm) above 54 percent. No single instance of initiation of ventricular tachycardia by atrial premature stimuli was observed in patients with a ventricular prematurity index below 54 percent or requiring more than one consecutive ventricular extrastimulus to have tachycardia initiated. Other features of patients showing initiation of ventricular tachycardia by atrial premature stimuli were a right bundle branch block configuration of the QRS complex during tachycardia in all seven patients and a relatively slow rate during tachycardia. In one patient ventricular tachycardia was terminated by a conducted atrial premature stimulus.

Adult↗
PubMed1980

Pericardiodiaphragmatic hernia.

Twenty-seven reported cases of pericardial diaphragmatic hernia are reviewed and another case is added. This entity may be congenital or traumatic in origin, the latter being more frequent at a ratio of 2:1. All patients except one were male and the mean age at diagnosis was 40 years. The patients were usually symptomatic, the most frequent complaints being of cardiac or respiratory origin. Pneumoperitoneum may be diagnostic although chest roentgenograms and contrast studies may suggest the diagnosis. Computed axial tomography and echocardiography may prove useful in the future. We believe the anterior abdominal approach is preferable to the transthoracic approach in reducing the hernia and repairing the defect because it affords better exposure and easier accessibility to other intraabdominal disease and can easily be converted into a median sternotomy if needed. The stomach and transverse colon became herniated most frequently and in only three cases was a sac found. The defect involves the central leaflet of the diaphragm and primary repair generally results in a good prognosis.

Adolescent↗
PubMed1980

Comprehensive clinical electrophysiologic studies in the investigation of documented or suspected tachycardias. Time, staff, problems and costs.

To assess time, staff, problems and costs involved in clinical electrophysiologic studies for documented or suspected tachycardia, 33 consecutive cases were analyzed prospectively. At least seven staff members were used for each study. Insertion of catheters required 24--105 minutes (mean 63 +/- 20 minutes). Programmed stimulation required 12--210 minutes (mean 87 +/- 38 minutes). Total fluoroscopy times were 6--67 minutes (mean 22 +/- 15 minutes). Each study used 360--2100 feet (mean 1260 +/- 390 feet) of recording paper. Detailed analysis of tracing took 1--11 hours (mean 5 +/- 2.5 hours). Delays occurred during electrophysiologic study in 25 cases (76%), with multiple causes of delay in 14 cases (42%). These were caused by 1) difficulty in obtaining venous access (five patients); 2) difficult initial catheter placement (15 cases); 3) repositioning of catheters during stimulation (17 cases); 4) sustained atrial fibrillation (four cases). Coronary sinus catheterization was achieved from the groin in 21 of 27 cases (78%) in whom a sustained attempt was made. The approximate cost of each study was greater than $800. Our data show that clinical electrophysiologic studies in the investigation and management of tachycardia are difficult, time-consuming and expensive.

Adolescent↗
PubMed1980

Pacing techniques in the treatment of tachycardias.

Pacemakers are playing an increasing role in the management of patients with tachycardia. Pacing to prevent tachycardia must be differentiated from pacing to terminate tachycardia. Pacing is of proven value in preventing ventricular tachycardia that occurs in the setting of complete heart block or the setting of drug-induced QT interval prolongation and may be valuable in some other patients with nonsustained ventricular tachycardia. Pacing termination has found its greatest use as an alternative to cardioversion in patients with atrial flutter, especially those with suspected digitalis toxicity or sick sinus syndrome or patients after cardiac surgery. Implanted pacemakers that can be activated by the patient are a promising area or investigation for the termination of tachycardias that are recurrent and debilitating despite medical therapy.

Arrhythmias, Cardiac↗
PubMed1979

Regional effects of propranolol on intraventricular conduction in coronary artery disease.

In canines, propranolol slows conduction in acutely ischemic, but not in normal tissues. To determine propranolol effects on conduction in patients with coronary artery disease, we studied 7 patients after left anterior descending coronary artery bypass graft surgery. Bipolar electrodes were placed in the atrium, left ventricle (in the left anterior descending distribution), and right ventricle. On postoperative day 7, 3 mg propranolol were given intravenously. At a constant artrially paced rate, conduction intervals were measured from the earliest onset of the QRS in 3 simultaneously recorded surface electrocardiogram (ECG) leads to the major deflection of the electrogram recorded from each ventricle. Ten minutes after injection, conduction in the left ventricle was slowed by 4 +/- 0.3 msec (10 +/- 0.9%) and in the right ventricle by 0.4 +/- 0.3 msec (1 +/- 0.9%). QRS duration changed -1 msec (-0.8%). Stimulus to Q, a measure of propranol effect on A-V conduction, changed 16 +/- 2%. The difference in propranolol effects on left and right ventricles was significant (p less than 0.001). We suggest that in patients with coronary artery disease (1) propranolol has local anesthetic effects in slowing conduction; (2) the effects of propranolol vary with the region of ventricular myocardium; and (3) propranolol slows conduction more in the left than right ventricle. This difference may be due to potentiation of drug effects in left ventricular tissue that is abnormal due to chronic coronary artery disease.

Adult↗
PubMed1979

Prognostic value of echocardiographic evaluation of septal function in acute anteroseptal myocardial infarction.

To determine the clinical usefulness of echocardiography in patients with anteroseptal myocardial infarction, echocardiograms were performed within 24 hours of admission on 40 patients with acute transmural anteroseptal myocardial infarction. Twenty-one patients had normal septal motion and septal systolic thickening, and 19 patients had abnormalities of one or both of these measurements. Of the 21 patients who had normal septal motion and thickening, only five developed congestive heart failure, none developed bundle branch block, and none died. Of the 19 patients with abnormal septal motion and/or thickening, 17 developed congestive heart failure (p less than .001), seven developed bundle branch block (p less than .001), and six died (p less than .001). Therefore, (1) electrocardiographic evidence of septal infarction does not correlate with abnormalities of the portion of septum seen on echocardiogram, and (2) patients with anteroseptal myocardial infarction and abnormalities of the septum on echocardiogram have more complications and a higher in-hospital mortality rate. These patients may have more extensive myocardial infarction predisposing to pump failure and possibly involving the conduction system.

Aged↗
PubMed1979

Reciprocal tachycardias using accessory pathways with long conduction times.

Three patients with reentrant tachycardia are described who had an accessory pathway with a very long conduction time that was incorporated in the tachycardia circuit. The accessory pathway was able to conduct in one direction only, in retrograde manner in two patients and in anteriograde manner in the remaining patient. Evidence is presented that reveals that in the first two patients the accessory pathway was septally located, had completely bypassed the normal atrioventricular (A-V) conduction system, had properties of decremental conduction, and had an atrial exit close to the coronary sinus and a ventricular exit relatively far from the atrioventricular A-V ring. In the third patient, who manifested wide QRS complex during tachycardia, the ventricular end of the accessory pathway seemed to be located close to the right ventricular apex. The atrial end of the pathway could not be localized exactly.

Adult↗
PubMed1979

Human pulmonary dirofilariasis presenting as a solitary pulmonary nodule.

A case of human pulmonary dirofilariasis had positive serologic testing postoperatively. Increased awareness of this entity as a cause of solitary pulmonary nodules may lead to preoperative serologic and intradermal testing, and to the possibility of arriving at a preoperative diagnosis.

Diagnosis, Differential↗
PubMed1979

Electrophysiological studies in patients with the Wolf-Parkinson-White syndrome.

Electrophysiologic studies in patients with the Wolff-Parkinson-White (WPW) syndrome are performed for diagnostic and therapeutic reasons. Surface electrocardiographic leads plus intracardiac electrograms from different locations are stimultaneously recorded. Programmed electrical stimulation of the heart permits confirmation of pre-excitation in questionable cases and assessment of the mechanism of the arrhythmias which these patients develop as well as their therapeutic approach. The most frequent form of paroxysmal regular tachycardia observed in WPW is based on an AV-junctional re-entry mechanism utilizing the accessory pathway in the retrograde direction. The second clinically relevant arrhythmia encountered in these patients is atrial fibrillation with very rapid ventricular rates due to almost exclusive A-V conduction by way of the accessory pathway. Ventricular fibrillation may occasionally ensue as a result of these fast ventricular rates during atrial fibrillation. Determination of the antegrade effective refractory period of the accessory pathway may identify the group of patients prone to the development of this complication. The intravenous injection of Ajmaline can by a non-invasive aid in the selection of patients for further electrophysiological evaluation when this drug fails to induce complete antegrade block over the accessory pathway during sinus rhythm. Patients with tachyarrhythmias which are difficult to control with conventional drug therapy should undergo an electrophysiological investigation to select either more effective antiarrhythmic treatment or, in medically refractory patients, appropriate pacing or surgical techniques.

Anti-Arrhythmia Agents↗
PubMed1978

Electrophysiologic effects of acute myocardial infarction in man.

Six patients undergoing surgery for ischemic heart disease were studied by means of epicardial electrodes affixed to the left ventricle. One patient who underwent triple coronary arterial bypass and plication of a left ventricular aneurysm had evidence of an acute myocardial infarction 1 day after operation. A surface electrocardiogram and a bipolar electrogram from the left ventricle were recorded before and after development of the infarction. The bipolar electrogram showed a marked loss of voltage and delay of conduction that were not present in the patients who underwent surgery but did not sustain an acute myocardial infarction. Thus, any acute myocardial infarction in conscious persons appears to be associated with areas of delayed epicardial action and diminution of local voltage. This observation suggests that the electrophysiologic mechanisms of infarction in man are similar to those of infarction in the dog.

Acute Disease↗
PubMed1975

Bladder outlet obstruction caused by vaginal fibromyoma: the female prostate.

Three patients with urinary difficulty were cured by surgical removal of a viaginal fibromyoma. The appearance of this benign tumor on an intravenous cystogram and cystoscopy as well as the clinical response to surgical removal bears similarity to the hypertrophied prostate in men. The best surgical technique for its removal is enucleation via a vaginal incision.

Adult↗