Duration of ECT-induced tachycardia as a measure of seizure length

Electroconvulsive therapy: a review on indications, methods, risks and medication

This paper reviews and presents data of practical impact for those administering electroconvulsive therapy (ECT). In the first section, physical and physiological aspects of the stimulus as well as methods of stimulation are discussed. The second section deals with indications for ECT, efficacy and treatment modalities such as seizure duration, treatment frequency and total number of ECT applications. The last section is devoted to side effects, risks, comedication and comorbidity.

Anaesthesia for electroconvulsive therapy - new tricks for old drugs: a systematic review

OBJECTIVE

The objective of this review is to investigate existing literature in order to delineate whether the use of anaesthesia and timing of seizure induction in a new and optimised way may improve the efficacy of electroconvulsive therapy (ECT).

METHODS

PubMed/MEDLINE was searched for existing literature, last search on 24 June 2015. Relevant clinical studies on human subjects involving choice of anaesthetic, ventilation and bispectral index (BIS) monitoring in the ECT setting were considered. The references of relevant studies were likewise considered.

RESULTS

Propofol yields the shortest seizures, etomidate and ketamine the longest. Etomidate and ketamine+propofol 1 : 1 seems to yield the seizures with best quality. Seizure quality is improved when induction of ECT is delayed until the effect of the anaesthetic has waned - possibly monitored with BIS values. Manual hyperventilation with 100% O2 may increase the pO2/pCO2-ratio, which may be correlated with better seizure quality.

CONCLUSION

Etomidate or a 1 : 1 ketamine and propofol combination may be the best method to achieve general anaesthesia in the ECT setting. There is a need for large randomised prospective studies comparing the effect of methohexital, thiopental, propofol, ketamine, propofol+ketamine 1 : 1 and etomidate in the ECT treatment of major depressed patients. These studies should investigate safety and side effects, and most importantly have antidepressant efficacy and cognitive side effects as outcome measures instead of seizure quality.

Heart rate changes during electroconvulsive therapy

BACKGROUND

This observational study documented heart rate over the entire course of electrically induced seizures and aimed to evaluate the effects of stimulus electrode placement, patients' age, stimulus dose, and additional predictors.

METHOD

In 119 consecutive patients with 64 right unilateral (RUL) and 55 bifrontal (BF) electroconvulsive treatments, heart rate graphs based on beat-to-beat measurements were plotted up to durations of 130 s.

RESULTS

In RUL stimulation, the initial drop in heart rate lasted for 12.5 ± 2.6 s (mean ± standard deviation). This depended on stimulus train duration, age, and baseline heart rate. In seizures induced with BF electrode placement, a sympathetic response was observed within the first few seconds of the stimulation phase (median 3.5 s). This was also the case with subconvulsive stimulations. The mean peak heart rate in all 119 treatments amounted to 135 ± 20 bpm and depended on baseline heart rate and seizure duration; electrode placement, charge dose, and age were insignificant in regression analysis. A marked decline in heart rate in connection with seizure cessation occurred in 71% of treatments.

CONCLUSIONS

A significant independent effect of stimulus electrode positioning on cardiac action was evident only in the initial phase of the seizures. Electrical stimulation rather than the seizure causes the initial heart rate increase in BF treatments. The data reveal no rationale for setting the stimulus doses as a function of intraictal peak heart rates ('benchmark method'). The marked decline in heart rate at the end of most seizures is probably mediated by a baroreceptor reflex.

Postictal asystole during ECT

BACKGROUND

Asystole is an uncommon but potentially fatal complication of electroconvulsive therapy (ECT). Several risks for poststimulus asystole have been described, but risks for asystole at other times have not.

METHOD

Two instances of ECT postictal asystole in healthy adult males are reported. Features in common are identified.

RESULTS

features shared differ from risk factors for poststimulus asystole. In common were adult but not geriatric age, male sex, good physical and cardiac health, mesomorphic habitus, anticholinergic pretreatment, vigorous ECT seizure, and low resting heart rate. Both patients showed postictal bradyarrhythmia at the previous ECT.

CONCLUSIONS

Postictal asystole has apparent similarities to postexertional asystole in athletes. The combination of higher pretreatment doses of an atropinic agent, a sympatholytic agent, and close monitoring of postictal cardiac rhythm should be considered with patients similar to ours, especially after occurrence of postictal bradyarrhythmia.

Physiological response to ECT stimulus dose

For a physiological effect to be useful to regulate the electrical stimulus dose used in electroconvulsive therapy (ECT), it must show sensitivity to the stimulus dose. In the analogy of using blood drug concentration to regulate drug dosage, this concentration must be sensitive to the dose. Accordingly, we examined the sensitivity of several physiological effects to ECT stimulus dose. Previously no substantial sensitivity of physiological effects was found when generally effective ECT methods were used. EEG post-ictal suppression, recruitment phase duration, wave form regularity and spike-and-wave frequencies, peak seizure heart rate (HR), and several types of seizure duration were measured with standard and higher dose stimuli given on separate days to 24 subjects. Left frontal to right temporal asymmetric bilateral stimulus placement was applied. Peak HR (P=0.007, t=2.7) and EEG recruitment phase duration (P=0.04, t=1.9) varied with stimulus dose, by 12 beats/min and 1.3 s, respectively. Only peak HR (P=0.02, t=2.2) varied with stimulus dose (by 6 beats/min) when subjects who showed only EEG seizure but no motor seizures were excluded. Subjects who maintained peak HR near their individual maximum values received fewer ECTs than other subjects (P=0.00003, t=5.20); this greater efficacy suggests that the peak HR reflects clinical efficacy as well as stimulus dose. In addition to EEG measurements, peak HR is a candidate to measure ECT seizure quality and provide feedback for stimulus dose regulation.

Generalization, duration, and low-frequency electroencephalographic persistence of bilateral electroconvulsive therapy seizure

Measurements were made at the beginning and end of a course of bifrontotemporal brief-pulse ECT for 28 males to both determine how well seizure generalization is maintained along the course of electroconvulsive therapy (ECT) and examine correspondence between low-frequency EEG activity and other seizure durations. Durations of spike electroencephalographic (EEG) paroxysmal activity, heart rate elevation, and Ionic-clonic activity decreased about 30% along the course, p < 0.0001, yet correlated highly at both times, I = 0.69 to 0.88, p < 0.0005, as did their changes: these correlations demonstrate high-seizure generalization and its maintenance. EEG low-frequency persistence, the difference between total and spike EEG paroxysmal durations, doubled along the course (p = 0.041), but showed no association with any other seizure duration measure. This absence of association suggests that low-frequency activity and other seizure duration measures describe separate phenomena and should be expressed separately, rather than combined as the (traditional) total EEG paroxysmal duration.

Cardiovascular response and seizure duration as determined by electroencephalography during unilateral electroconvulsive therapy

The effect of pulse unilateral electroconvulsive therapy (ECT) on heart rate, blood pressure and the product of heart rate and systolic blood pressure, an index of myocardial oxygen consumption, was studied during 48 ECT sessions in 7 patients with major depression. Intra-individually, hyperventilation-induced hypocapnia compared with normocapnia markedly augmented the ECT-induced increase in heart rate (47% vs 28%) and the product of heart rate and systolic blood pressure (82% vs 60%). Over all ECT seizures, the maximum and increase in heart rate and the product of heart rate and systolic blood pressure were significantly correlated with seizure duration as determined by electroencephalography. However, significant correlations were only present for the seizures during hypocapnia and not during normocapnia. Combining measures of magnitude and length of ECT-induced tachycardia to motor responses may increase the potential for clinical seizure evaluation.

Theophylline reversal of electroconvulsive therapy (ECT) seizure inhibition

Oral sustained-release theophylline 200-400 mg, given 10 hours prior to electroconvulsive therapy (ECT) increased ECT seizure length in each of eight male patients who had shown unacceptably short seizures. The increase was on average 13.9 (+/- 6.0, SD) sec (p = .00016 by t test; p = .0000034 by exact probability). The absence of unduly prolonged seizures was attributed to previously demonstrated high seizure thresholds and to relatively low concentrations of theophylline. No adverse effects from theophylline were seen.

Acute effects of single and repeated electroconvulsive therapy on plasma catecholamines and blood pressure in major depressive disorder

The role of activation of adrenergic neurons by electroconvulsive therapy (ECT) in its antidepressant action was studied by examining acute sympathetic nervous system (SNS) responses to ECT during a course of treatment in patients with melancholia. ECT had an acute dose-dependent effect on plasma norepinephrine (NE) level and blood pressure. The postictal increase in plasma NE and blood pressure was independent of electrical seizure duration. Acute levels of NE and epinephrine after ECT correlated positively with ECT dosage. No cumulative effect of repeated ECT was found on the SNS responses. ECT does activate the SNS in a dose-dependent fashion. However, alternative strategies seem necessary for studying the action of ECT on noradrenergic neurons to identify effects that are cumulative, correspond more closely to the time course of its antidepressant action, and correlate with clinical outcome.

Would monitoring by electroencephalogram improve the practice of electroconvulsive therapy?

Estimates of seizure length made by the treating psychiatrist were compared with estimates made by six-channel EEG in 100 electroconvulsive treatments in 22 depressed patients. In 70 treatments the doctor observed a fit which was shorter than 25 seconds. No doctor restimulated a patient in such a case and on only three occasions was the electrical stimulus increased at the next treatment. EEG monitoring revealed that only 30 of the treatments resulted in a seizure of less than 25 seconds, and this was detected in almost all cases by the treating doctor. The potential value of EEG monitoring was to identify patients whose visible seizure was short but where cerebral seizure length was satisfactory. Trainee psychiatrists often mismanage patients who have short seizures.