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Biomedical subjects

N Goldschlager

Publications and source records attributed to N Goldschlager.

At least 19 recordsLinked to original sources

Dipyridamole perfusion scintigraphy: the experience with its application in one hundred seventy patients with known or suspected unstable angina.

We evaluated the safety, accuracy, and potential clinical utility of intravenous dipyridamole perfusion scintigraphy with thallium-201 in 170 patients, 78 with suspected and 92 with known unstable angina. All had coronary angiography. Noncardiac side effects (26%), induced chest discomfort (44%), and ST segment changes (12%) were similar in the two groups. No significant arrhythmias occurred. Two patients had prolonged chest pain, both with extensive reversible image abnormalities and associated creatinine kinase-MB release. Both had elective bypass surgery. Twenty-eight patients had normal coronary arteries, and 35 had single-vessel disease. Scintigraphic per patient sensitivity and specificity were 91% and 79% with a per vessel sensitivity of 74% and a per vessel specificity of 78% without between-group differences. During a brief follow-up period, 62 patients with image abnormalities had coronary revascularization, and there were seven deaths without intergroup differences. In a similar patient group that did not have angiography, scintigraphic defects were less frequent and less extensive, revascularization was not performed, and subsequent deaths occurred less often. Dipyridamole perfusion scintigraphy is an accurate alternative to exercise testing in the evaluation of patients with unstable angina pectoris. Although not without risk, the method appears relatively safe and should be considered as a guide to diagnosis, and probably to prognosis and management.

Adult

Ventricular cross stimulation using a pacing system analyzer.

Cross stimulation refers to the situation in which a pacing lead positioned in one cardiac chambers results in stimulation of another chamber. We report three cases of ventricular cross stimulation observed at the time of pacing system implantation. The cross stimulation occurred through bipolar atrial and ventricular leads connected in bipolar configuration to a dual chamber pacing systems analyzer. Analysis of events during cross stimulation indicated that the current pathway was occurring within the pacing system analyzer itself, due to low resistance internal connections between the ring electrodes of the atrial and ventricular pacing systems analyzer channels. Cross stimulation within the pacing system analyzer can be eliminated by making the ventricular channel unipolar. Awareness of the phenomenon reported here should assist in the avoidance of the mistaken diagnosis of pacing lead migration and malposition during pacing system implant procedures.

Aged

Permanent cardiac pacing for brady-arrhythmia.

The indications for and technology associated with permanent cardiac pacing have undergone major changes during the past decade. In contrast to the 1970s, most patients now receive cardiac pacing devices subsequent to the diagnosis of sick sinus syndrome. However, since this condition is prevalent in elderly patients, it is crucial that indications for pacing be critically evaluated and pacing recommended only for those with documented symptoms or marked abnormalities indicative of high risk for a subsequent cardiac event. This is particularly important because pacing has not been shown to influence survival in these patients. The technological advances in pacing devices during the last ten years now provide many desirable options. As a result, available pacemakers range from very simple to highly complex; accordingly, they have a wide range of prices. It is more important than ever to carefully select the appropriate pacing device for a given patient, since its cost, longevity, and required follow-up may differ greatly.

Bradycardia

Torsade de pointes during administration of pentamidine isethionate.

Pentamidine isethionate is a diamidine compound used in the treatment of a number of parasitic diseases, notably Pneumocystis carinii pneumonia. Although cases of sudden death have been reported during the administration of pentamidine, there have been no reported cases in the literature of pentamidine-associated arrhythmias. Reported in this study are two cases of torsade de pointes occurring during the prolonged administration of pentamidine. In addition, electrocardiographic changes of marked QT interval prolongation, pronounced precordial T wave abnormalities, and ST segment changes were shown in both patients. Mild hypomagnesemia coexisted in both cases, but torsade de pointes persisted in one patient and electrocardiographic changes remained in both cases despite magnesium replacement. QT interval prolongation and electrocardiographic abnormalities resolved slowly over several days to weeks, paralleling the known elimination kinetics of pentamidine. These data suggest a proarrhythmic effect of pentamidine isethionate.

Acquired Immunodeficiency Syndrome

Advances in DDD pacing.

Advances in DDD design are increasingly directed toward imitating actual cardiac physiology. Eventually, biosensors will command implanted dual chamber units' responses, affording the most physiologic of circumstances. Since these improved design features are quite complex, the care of the paced patient may well have to be performed in specialized centers. The responsibility thereby incurred mandates to those involved in cardiac pacing critical validation of the actual clinical relevance of newer DDD features.

Atrioventricular Node

Determinants of prognosis of patients with aortic regurgitation who undergo aortic valve replacement.

Insidious and potentially irreversible left ventricular dysfunction may develop in patients with aortic regurgitation. To determine whether preoperative variables can predict postoperative outcome, 113 consecutive patients with aortic regurgitation who underwent surgical correction between 1962 and 1977 were studied and survivors were followed up for 4.6 +/- 3.3 years. Clinical and hemodynamic examinations were made in all patients before the operation. Echocardiograms were performed in 44 patients preoperatively and in 36 patients postoperatively. Perioperative or postoperative death due to congestive heart failure occurred in only eight patients (19%). No statistically significant predictors of total mortality or death due to cardiac failure were found based on preoperative clinical, hemodynamic or echocardiographic findings. Survivors of the operation showed significant functional improvement: preoperatively, 77% of all patients were in functional class III or IV; postoperatively, 84% of patients were in class I or II (p less than 0.0001). A weak statistical correlation of functional improvement was found with a preoperative presence of increased cardiac diameter on the chest radiograph (p less than 0.05) and the severity of left ventricular hypertrophy (p less than 0.05). Improvement of left ventricular function was also consistently found in survivors and correlated best with the degree of preoperative preservation of left ventricular function. Patients with an echocardiographic preoperative fractional shortening of the minor diameter greater than 26%, end-systolic dimension less than 55 mm and end-diastolic dimension less than 80 mm were most likely to have normal function after the operation. It is concluded that operative mortality and survival after surgical correction of aortic regurgitation cannot be accurately predicted from preoperative findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult