Alan N. Weiss

Tricyclic antidepressant plasma levels and adverse effects after overdose.

Forty patients ingesting tricyclic antidepressant (TAD) overdoses were studied as a pharmacologic model to determine whether total tricyclic antidepressant plasma levels correlated with major adverse effects and electrocardiographic findings. Maximum TAD plasma levels were higher in patients who died (p < 0.025) or had cardiac arrest (p < 0.02), needed respiratory support (p < 0.005), were unconscious (p < 0.02), had grand mal seizures (p < 0.001), ventricular rate ≥ 120/min (p < 0.01), cardiac arrhythmia (p < 0.05), QRS duration ≥ 100 msec (p < 0.00l), or bundle branch block (p < 0.05). TAD plasma levels correlated with the dose ingested by history (N = 29, r = 0.58, p < 0.001). Measurement of total TAD (free and protein‐bound) appears to correlate well with biologic response.

Ultrasound integrated backscatter tissue characterization of remote myocardial infarction in human subjects

To determine whether quantitative ultrasound tissue characterization differentiates normal myocardial regions from segments of remote infarction, 32 consecutive patients with a diagnosis of previous myocardial infarction were evaluated. Images were obtained in real time with a modified two-dimensional ultrasound system capable of providing continuous signals in proportion to the logarithm of integrated backscatter along each A line. In 15 patients, adequate parasternal long-axis images that delineated both normal and infarct segments were obtained with standard time-gain compensation. Image data were analyzed to yield both magnitude and delay (electrocardiographic R wave to nadir normalized for the QT interval) of the cyclic variation of backscatter. Cyclic variation was present in 55 of 56 normal myocardial sites, averaging (mean +/- SEM) 3.2 +/- 0.2 dB in magnitude and exhibiting a mean normalized delay of 0.87 +/- 0.03. The magnitude of cyclic variation in infarct segments was significantly reduced to 1.1 +/- 0.2 dB (42 sites), and the delay was markedly increased to 1.47 +/- 0.12 (21 sites) (p less than 0.0001 for both). In 20 of 42 infarct sites, no cyclic variation was detectable. Thus, ultrasound tissue characterization quantitatively differentiated infarct segments from normal myocardium in patients with remote myocardial infarction.

A Prospective Analysis of Near-Death Experiences in Cardiac Arrest Patients

The objective of this study was to assess prospectively the frequency of near-death experiences (NDEs) in patients suffering a cardiac arrest, to characterize these experiences, and to assess their impact on psychosocial and spiritual attitudes. We prospectively evaluated all patients who suffered a cardiac arrest at Barnes-Jewish Hospital from April 1991 through February 1994, excluding those in the surgical intensive care unit, using a scale designed to specify criteria for NDEs, a recorded interview regarding the experience, an experience rating form, and a follow-up questionnaire regarding psychosocial attitudinal life changes. Of the 174 patients who suffered a cardiac arrest, 55 patients survived, of whom 30 patients were interviewable. Of those 30 patients interviewed, seven (23 percent) had a NDE, and four others (13 percent) reported an NDE during a prior life-threatening illness. The experiences were most frequently characterized by ineffability, peacefulness, painlessness, lack of fear, detachment from the body, and no sense of time or space. Significant differences were noted in the follow-up psychosocial assessment between patients who experienced an NDE and those who did not with regard to personal understanding of life and self, attitudes toward others, and changes in social customs and religious/spiritual beliefs. Of importance, patients reported it was beneficial to receive psychosocial support before hospital discharge after having an NDE. The results suggest that NDEs are fairly common in cardiac arrest survivors. The experiences consisted of a number of core characteristics and changed psychological, social, and spiritual awareness over both the short and long term.

Norepinephrine and Epinephrine Secretion From a Clinically Epinephrine-Secreting Pheochromocytoma

Abstract A 46 year old woman suffered five episodes characterized by hypotension, pulmonary edema, ventricular arrhythmias and cardiopulmonary arrest. She was found to have increased urinary total metanephrine and vanillylmandelic acid excretion and a mass in the left adrenal gland was detected on computed tomographic scanning. Because of the clinical picture of an epinephrine-secreting pheochromocytoma, she was prepared for adrenalectomy only with a beta-adrenergic blocking agent. Hypertension did not develop preoperatively. Surgery was complicated by severe hypertension, with blood pressure levels as high as 240130 mm Hg, requiring the intravenous administration of alpha-adrenergic blocking agents. Plasma epinephrine and norepinephrine values, determined preoperatively but reported postoperatively, confirmed the presence of markedly elevated plasma epinephrine levels (1,210 and 1,840 pg/ml). Notably, however, plasma norepinephrine concentrations were also increased (1,980 and 3,000 pg/ml) and the tumor contained large amounts of norepinephrine as well as epinephrine. Thus, combined norepinephrine secretion was documented in a patient with the clinical picture of an epinephrine-secreting pheochromocytoma. In our judgement, such patients should be prepared for surgery with both beta- and alpha-adrenergic blocking agents. This patient exemplified the utility of isotope derivative measurements of plasma norepinephrine and epinephrine concentrations in the diagnosis of pheochromocytoma. Of 15 patients with surgically proved pheochromocytomas studied in our laboratory, plasma catecholamine concentrations were increased in all 14 with clinical manifestations compatible with catecholamine excess. Plasma catecholamine concentrations were not distinguishable from normal in one patient studied only because of a family history of pheochromocytoma.

Insensitivity of echocardiography in detecting mitral valve prolapse in older patients with chest pain

Abstract Although echocardiography has proved useful in detecting mitral valve prolapse, its limitations have not yet been adequately defined. This study was designed to evaluate the prevalence of false negative echocardiograms in patients with angiographically proved mitral valve prolapse. Twelve patients, eight men and four women with a mean age of 47 years, were selected on the basis of the results of cardiac catheterization for chest pain. Each patient had moderate to severe mitral valve prolapse, confirmed angiographically by two observers, with no coronary artery disease or other detectable cardiac abnormalities. Clinically, a systolic click was detected in three patients, a mid-systolic murmur in five, an abnormal electrocardiogram in four and a positive maximal treadmill stress test in two of eight tested. Left ventricular angiograms exhibited anterior and posterior leaflet prolapse in five, and posterior leaflet prolapse alone in seven. High quality echocardiograms were obtained in 11 patients; one record of inadequate quality was excluded. The echocardiograms revealed mitral valve prolapse in only one case, and were “probably” negative in two, and clearly negative in eight. Although these results may reflect the well recognized variable clinical expression of this syndrome, they indicate that false negative echocardiograms are common in this selected older population of patients with angiographic mitral valve prolapse who present with chest pain and few other clinical features. Thus, caution must be exercised in the clinical interpretation of a single echocardiogram negative for mitral valve prolapse.

Technetium-99m stannous pyrophosphate scintigrams in normal subjects, patients with exercise-induced ischemia and patients with a calcified valve

Although technetium-99m stannous (99mTc[Sn]) pyrophosphate has been shown to be a specific and sensitive index of myocardial infarction, abnormal images have been reported in patients with unstable angina or ventricular aneurysm. Sixty-one subjects--33 patients subjected to maximal treadmill stress testing, 23 normal subjects and 5 patients with a calcified aortic or mitral valve--underwent imaging with 99mTc(Sn) pyrophosphate to determine whether abnormal images are associated with (1) exercise-induced ischemia, (2) delayed clearance of tracer from the blood pool, or (3) calcified intracardiac structures. Myocardial injury was excluded on the basis of normal MB creatine kinase (CK) values in all patients with stress testing. All eight patients with an abnormal exercise stress test had normal images. Four of 25 patients with a normal exercise stress test had diffusely abnormal images. In some normal subjects diffusely abnormal images were present 60 minutes after injection of the tracer, but became normal 90 to 120 minutes after injection. Variations in clearance of tracer from the blood pool were noted in this group. Patients with a calcified aortic or mitral valve had normal images. We conclude that (1) exercise-induced ischemia is not associated with abnormal 99mTC(SN) pyrophosphate images; (2) images are not necessarily abnormal in patients with a calcified valve; and (3) delayed removal of tracer from the cardiac blood pool may result in diffusely abnormal images even in normal subjects; in these cases, repeat images should be obtained at least 2 hours after injection of the tracer to avoid false abnormal images.

Massive Pulmonary Embolism Permitting Paradoxical Systemic Arterial Embolism: Successful Surgical Management

The case of a young woman, receiving oral contraceptives, who developed massive pulmonary embolism producing circulatory collapse and paradoxical arterial embolism through a patent foramen ovale is documented.. Limb viability was threatened. Emergency management included removal of arterial and pulmonary emboli, surgical closure of the patent foramen ovale, inferior caval partitioning, ovarian vein ligation, and short-term anticoagulation. Recovery was rapid and complete.

False Positive 99mTc (Sn) Pyrophosphate Myocardial Infarct Images Related to Delayed Blood Pool Clearance

Three patients with atypical chest pain who were evaluated by exercise treadmill stress testing and 99mTc (Sn) pyrophosphate imaging had diffusely abnormal images after exercise and 24 hours later. These patients had normal exercise tests and no evidence of myocardial infarction. Repeat images several months later on each patient were again abnormal when imaged one hour after administration of the radiopharmaceutical but were normal on delayed imaging suggesting delayed blood pool clearance. Our findings suggest that a diffusely abnormal image one hour after injection may represent delayed blood pool clearance, and persistance of this abnormal image for greater than two hours after injection should be demonstrated before interpreting the study as abnormal.