Biomedical subjects
Publications and source records attributed to W V McCall.
We report a child who demonstrates near electrocerebral silence secondary to obstructive apnea during polysomnography. The mechanism of this suppression of cortical activity appears to be related to hypoxemia in the absence of a malignant arrhythmia.
Explore the source record for details and available documents.
Electroconvulsive therapy (ECT) induces sympathetically mediated hemodynamic alterations that can be associated with myocardial ischemia and arrhythmia generation. Esmolol, a short-acting beta-blocker, blunts the hypertension and tachycardia seen with ECT. The purpose of this study is to determine whether esmolol use during ECT reduces the incidence of myocardial ischemia or arrhythmias after ECT. In a randomized, double-blind, placebo-controlled protocol, with each patient acting as his/her own control, the effects of esmolol on the incidence of myocardial ischemia and arrhythmias were studied using two-lead Holter monitoring for at least 2 h post-ECT. Nineteen patients underwent 71 ECT treatments (34 placebo, 37 esmolol), recording 746 h of Holter data. The esmolol group had significantly reduced heart rate and mean arterial pressure immediately after ECT. There was no difference in the incidence of ECG defined ischemia post-ECT between groups, with 7 of 19 (36.8%) patients in the esmolol group showing ST-segment depression compared with 5 of 19 (26.3%) in the placebo group. There was no difference between groups in arrhythmia detection. This experiment demonstrates that (a) ECT is associated with a significant incidence of ST-segment depression, (b) esmolol blunts the sympathetic discharge during ECT, and (c) esmolol does not reduce the incidence of post-ECT ischemia or arrhythmia.
Intravenous beta-blockers are an effective means of controlling heart rate and blood pressure during electroconvulsive therapy (ECT), but have been shown to decrease seizure duration. While the importance of seizure duration to the antidepressant response of ECT grows less certain, there is growing evidence that seizure morphology predicts the antidepressant effect of ECT. This study examined the impact of esmolol pretreatment on seizure morphology. Eighteen depressed patients (6 men, 12 women; 69 +/- 12.8 years old) received ECT with and without esmolol pretreatment in a randomized, blinded crossover design. The seizures were blindly rated for duration of motor convulsion, duration of electroencephalogram (EEG) seizure, degree of seizure regularity, and degree of postictal EEG suppression. Esmolol shortened the duration of the motor convulsion and degraded the quality of the ictal regularity. Routine administration of intravenous esmolol before ECT may cause a decrease in ictal regularity. Careful consideration should be given to the potential benefits of esmolol versus the deleterious effect on the electrophysiologic process. Esmolol may still be indicated on a case-by-case basis for extreme tachycardia or hypertension associated with ECT, and presumably poses no problem for the therapeutic effect of ECT if given after the seizure is over.
Neurogenic pulmonary edema (NPE) is thought to rarely occur after seizures. Paradoxically, NPE is frequently found (>80%) at autopsy in epileptic patients who die unexpectedly. The reason for the discrepancy between the frequency of NPE found at autopsy and that after uncomplicated seizures is unclear. The literature suggests that subclinical NPE occurs rarely after uncomplicated seizures and resolves within a few hours, but is undetected because of infrequent use of routine chest radiographs early after a seizure occurs. This pilot study examined the frequency of subclinical, radiographically confirmed NPE after electroconvulsive therapy (ECT)-induced seizures. If shown to occur, ECT-induced subclinical NPE would provide an easily reproducible model to study NPE after seizures in patients with epilepsy. Given that sudden unexplained death syndrome accounts for approximately 10% of the deaths in patients with epilepsy, an easily reproducible model for NPE would have heuristic value. We examined 12 patients undergoing ECT for depression with chest radiographs before and after ECT. In this group, only 1 of the 12 patients had subclinical NPE in their post-ECT radiograph. We conclude that subclinical NPE does not significantly occur after seizures in patients undergoing ECT and therefore, would not serve as an application for research.
Recent evidence suggests that attributes of the ictal electroencephalogram (EEG) may be clinically useful for estimating the extent to which the electroconvulsive therapy (ECT) stimulus exceeds the seizure threshold (relative stimulus intensity). Such a tool could allow a practitioner, who chose, on the basis of expected therapeutic response and side effect rates, to implement stimulus dosing to maintain relative stimulus intensity over the treatment course, despite the uncertain rise in seizure threshold that occurs. One potential confounding factor is a possible systematic change in the ictal EEG over the treatment course that is not due to changes in seizure threshold. We explored the effect of treatment number by comparing ictal EEG data obtained at treatments across the ECT course that were delivered at the identical relative stimulus intensity. We found that the ictal EEG at treatment 1 was characterized by a greater mid-ictal amplitude and post-ictal suppression (trend) than subsequent treatments for barely suprathreshold unilateral ECT, but not for barely suprathreshold bilateral or moderately suprathreshold unilateral ECT, and that this change may affect therapeutic effectiveness. These findings suggest the importance of treatment-number effects for the clinical application of the ictal EEG and point to possible physiological differences between unilateral and bilateral ECT.
BACKGROUND: Asystole is an uncommon but potentially fatal complication of electroconvulsive therapy (ECT). Although the risk of asystole can be reduced with anticholinergic medications, the recent emphasis on new modifications of technique (first, the use of subconvulsive stimuli to titrate the seizure threshold, and second, pretreatment with intravenous beta-blockers) may increase the risk of asystole in ECT patients. METHOD: I present four new cases of asystole in ECT and outline a scheme for anticipating and preventing asystole. RESULTS: An episode of asystole did not prove to be an obstacle to further uncomplicated ECT. CONCLUSION: If risk factors contributing to asystole are reduced and adequate doses of intravenous atropine are on hand, a patient's ECT treatments need not be interrupted.
This study examines the relationship of serum prolactin changes (delta PRL) to variations in electrode placement after controlling for differences in the convulsive threshold. Previous studies showing greater release of PRL with bilateral (BL) compared with right unilateral (RUL) electrode placement were conducted without knowledge of the convulsive threshold. Twenty-two patients each received threshold RUL, threshold BL, 2.25 times threshold RUL, and 2.25 times threshold BL ECT. Serum PRL was collected 5 min before and 15 min after each electroconvulsive therapy (ECT). The convulsive threshold was greater for BL than RUL electrode placement. delta PRL was greater with BL than RUL ECT at comparable relative stimulus intensities. delta PRL was not correlated with seizure duration or absolute stimulus dose.
Ictal EEG indices show promise for separating individual ECT seizures on the basis of treatment electrode placement (ELPL), relative stimulus intensity (Dose), and expected therapeutic response. One factor impeding the effective clinical implementation of ictal EEG indices for these purposes is uncertainty as to the relative utility of lower and higher frequency EEG activity. Recent articles are contradictory in this regard, but no data exist addressing this issue. As a result, we reanalyzed data from 44 subjects in two studies and compared the relative ability of ictal EEG data in three frequency bands to differentiate seizures as a function of ELPL, Dose, and therapeutic response. We found that the frequency band that best differentiated these groups depended on the EEG measure used, the temporal portion of the seizure, and whether ELPL, Dose, or therapeutic response was being compared.
Titration of the electroconvulsive therapy (ECT) stimulus to the patient's convulsive threshold is the only way to directly assess the patient's seizure threshold. This technique is presently practiced by 39% of ECT providers, according to a recent survey. Because multiple variables influence the seizure threshold in patients, multivariate statistical methods may provide a useful strategy to determine which variables exert the most influence on convulsive threshold. A multivariate ordinal logistic model of seizure threshold was developed on an experimental group of 66 consecutive patients undergoing titrated right unilateral (RUL) ECT for major depression. The accuracy of the model was cross-validated on a second group of 40 patients undergoing similar RUL ECT procedures. The final multivariate ordinal logistic regression model for the seizure threshold level (STL) was significant (Likelihood ratio chi 2 = 54.115; p < 0.0001:R2 = 0.313). Increasing age, African-American race, and longer inion-nasion distances (p < 0.06) predicted higher STL. Female gender was associated with a lower STL. The ability of the final model to accurately predict STL for the validation group was fair (pairwise correlation was 0.576; p < 0.001). The model did well for predicting lower STL, but fared poorly for higher STL. In conclusion, modeling STL may help establish the relative contribution of variables thought to be important to seizure threshold. However, STL models remain impractical for clinical applications in estimating seizure threshold at this time, and empirical stimulus titration should be used.
Over the past 15 years, there has been considerable debate concerning the extent to which insomnia patients can be classified into diagnostic subtypes. Despite this debate, relatively little research has been conducted to empirically determine whether naturally occurring insomnia subtypes might be identified within populations of sleep clinic patients. In the current study we used a hierarchical cluster analysis to empirically identify subtypes among a mixed group of normal sleepers and the insomnia outpatients who presented to our sleep center over the past decade. Using factor-analytically derived composite variables that summarized data obtained from sleep history questionnaires and polysomnographic monitoring, this clustering procedure resulted in the identification of 14 subgroups that varied between four and 34 patients/subjects in size. Subsequently, subgroup mean scores for the composite variables used in the clustering procedure were used to construct profiles for each of the 14 clusters. A multivariate profile analysis, employed to elucidate subgroup differences, showed that these cluster profiles differed in terms of their configural shapes, average elevations, and degrees of interscale differences. Furthermore, both DSM-III-R (American Psychiatric Association) and International Classification of Sleep Disorders (ICSD) insomnia diagnoses, assigned independent of cluster findings, suggested that these subtypes differed significantly in regard to their diagnostic compositions. Nevertheless, a far-from-perfect concordance was observed between such clinically assigned diagnoses and cluster group membership. In fact, many of the empirically identified groups were composed of various DSM-III-R and/or ICSD diagnostic subtypes. These results provided only partial support for current DSM and ICSD insomnia categories. However, our results support the existence of multiple, clinically discrete insomnia subtypes and provide information that may be useful in future revisions of current insomnia nosologies.
Explore the source record for details and available documents.
Twenty-two patients with major depression received a course of right unilateral ECT. The convulsive threshold (CT) was determined on the first treatment. Subsequent treatments were approximately 2.25 times CT. Seizure morphology for treatments 2-6 were rated for regularity (0-6 scale; low-high) and postictal suppression (0-3; low-high). Ratings of postictal suppression were log transformed to improve the approximation to a normal distribution. A preliminary analysis of variance with CT as the independent variable compared the seizure ratings at low, mid, and high CT. Second, linear regression models for the mean values of seizure regularity and postictal suppression were determined using age, gender, and the CT as predictor variables. The degree of postictal suppression varied inversely with age, male gender, and CT in this study. Our results suggested that CT made the greatest contribution to the model. Future studies examining the predictive value of seizure morphology parameters to clinical outcome should include measurement of CT.
Cerebral aneurysms or recent surgical repair of aneurysms are relative contraindications for electroconvulsive therapy (ECT), yet the literature contains at least three cases in which ECT resulted in no known CNS complications. The following case describes a course of ECT in a patient 4 months after he had undergone surgical repair of a posterior cerebral artery aneurysm. Blood pressure control in patients with CNS aneurysms and repaired aneurysms can be achieved through choice of anesthetic agent, and intravenous antihypertensives, thus reducing the risk of cerebrovascular complications.
Twenty depressed patients (4 men, 16 women; mean age 67 years) received right unilateral (RUL) electroconvulsive therapy (ECT). The ictal electroencephalogram (Fp1-A1) was blindly rated on a 7-point scale for regularity of morphology at treatments two, four, and six. Seizure regularity declined during the course of ECT.
It is well established that, as a group, insomnia patients overestimate sleep onset latency (SOL) and underestimate total sleep time (TST) when compared to objective polysomnographic (PSG) findings. Whether a similar phenomenon occurs with other sleep disorders is not fully established. We compared the PSG sleep of 84 patients with suspected sleep apnea (SA) to their subjective experience of sleep reported on a sleep diary the morning after PSG testing. Both patients with SA (SA+) and those without (SA-) tended to overestimate SOL, but the SA+ group (n = 50) made larger overestimations (p < 0.02). The SA+ and SA- groups also differed in their accuracy at estimating TST, with SA+ patients underestimating TST (p < 0.05). These findings support the premise that marked discrepancies between subjective and PSG-determined sleep may not be limited to insomnia, but present in other sleep disorders as well, and should be appreciated by practitioners when obtaining sleep histories.
Sleep complaints are common in geriatric patients. The clinician's first task is to separate sleep problems originating in the physiologic changes of aging from those originating in pathological processes. Normal elderly persons have greater difficulty falling asleep and staying asleep, compared with younger persons, and sleep is qualitatively more shallow with more involuntary movements and abnormal breathing. Sleep complaints reach a pathological level as elders begin to experience deterioration of function during their period of normal wakefulness, manifested as excessive sleepiness, concentration deficits, and mood changes, or the emergence of bizarre or dangerous behavior during sleep. Sleep disorders are associated with excess physical and psychiatric morbidity and are treatable. An approach focused on sleep-related syndromes is a useful basis for rational treatment, and the treatment of many sleep disorders can be provided without expensive sleep laboratory testing.