Acute effects of ECT on cardiovascular functioning: relations to patient and treatment variables

Current electroconvulsive therapy practice and research in the geriatric population

Electroconvulsive therapy (ECT) is utilized worldwide for various severe and treatment-resistant psychiatric disorders. Research studies have shown that ECT is the most effective and rapid treatment available for elderly patients with depression, bipolar disorder and psychosis. For patients who suffer from intractable catatonia and neuroleptic malignant syndrome, ECT can be life saving. For elderly patients who cannot tolerate or respond poorly to medications and who are at a high risk for drug-induced toxicity or toxic drug interactions, ECT is the safest treatment option. Organic causes are frequently associated with late-life onset of neuropsychiatric conditions, such as parkinsonism, dementia and stroke. ECT has proven to be efficacious even when these conditions are present. During the next decade, research studies should focus on the use of ECT as a synergistic therapy, to enhance other biological and psychological treatments, and prevent symptom relapse and recurrence.

Relationship between body mass index and blood pressure elevation during electroconvulsive therapy

STUDY OBJECTIVE

To evaluate the relationship between body mass index (BMI) and blood pressure (BP) elevation during electroconvulsive therapy (ECT).

DESIGN

Descriptive epidemiological study.

SETTING

Operating room of a university-affiliated hospital.

PATIENTS

All patients who received ECT at the Tokyo Metropolitan Hiroo Hospital from May 2005 to March 2009.

INTERVENTIONS

All patients received routine ECT treatment.

MEASUREMENTS

Systolic BP (SBP) elevation during ECT, BMI, baseline SBP, age, electroencephalographic seizure duration, ECT stimulating dose, diagnosis, and gender were all recorded.

MAIN RESULTS

Patients with higher BMI tended to have greater SBP elevation after ECT. There was no correlation between elevated SBP and other factors. The degree of elevation of SBP after ECT was linearly related to BMI.

CONCLUSION

BMI correlates with BP elevation during ECT.

Is successful electroconvulsive therapy related to stimulation of the vagal system?

BACKGROUND

Electroconvulsive therapy (ECT) has been shown to exhibit strong beneficial effects in the treatment of major depressive disorder (MDD). While the exact underlying mechanisms are under debate, a role for the sympathetic response upon ECT has been suggested. When assessing patients with MDD for autonomic function, however, a loss of vagal function is prominent.

OBJECTIVE

Here, we aimed to assess the immediate effects of ECT on vagal activity and to test the hypothesis that surrogates of the latter correlate with therapeutic outcome.

METHODS

Twenty patients with MDD who underwent ECT treatment were assessed regarding their vagal function using electrophysiological measures and determination of pancreatic polypeptide (PP), which is known to be released upon vagal stimulation. Parameters were correlated to the improvement of disease severity upon ECT treatment.

RESULTS

Patients showed a significant increase of PP shortly after ECT which correlated with clinical improvement. Furthermore, the described association with the sympathetic phase after ECT could be verified.

CONCLUSION

ECT increases vagal activity which might be associated with the beneficial effect seen following this treatment. PP elevation after administration of ECT might be a useful parameter to estimate the degree of such vagal stimulation after treatment.

Differential heart rate response to magnetic seizure therapy (MST) relative to electroconvulsive therapy: a nonhuman primate model

Electroconvulsive therapy (ECT) is an effective treatment for severe depression; however, the induced therapeutic seizure acts on the autonomic nervous system and results in significant cardiac effects. This is an important consideration particularly in the elderly. Magnetic seizure therapy (MST) is in development as a less invasive alternative, but its effects on cardiac function have not been studied. We sought to model those effects in nonhuman primates to inform the development of safer neurostimulation interventions. Twenty four rhesus monkeys were randomly assigned to receive 6 weeks of daily treatment with electroconvulsive stimulation (ECS), magnetic seizure therapy (MST) or anesthesia-alone sham. Digitally acquired ECG and an automated R-wave and inter-R interval (IRI) sampling were used to measure intervention effects on heart rate (HR). Significant differences between experimental conditions were found in the HR as evidenced by changes in the immediate post-stimulus, ictal and postictal epochs. Immediate post-stimulus bradycardia was seen with ECS but not with MST. ECS induced significantly more tachycardia than MST or sham in both the ictal and postictal periods. MST resulted in a small, but statistically significant increase in HR during the postictal period relative to baseline. HR was found to increase by 25% and 8% in the ECS and MST conditions, respectively. MST resulted in significantly less marked sympathetic and parasympathetic response than did ECS. This differential physiological response is consistent with MST having a more superficial cortical site of action with less impact on deeper brain structures implicated in cardiac control relative to ECT. The clinical relevance of the topographical seizure spread of MST and its associated effects on the autonomic nervous system remain to be determined in human clinical trials.

Myocardial stunning after electroconvulsive therapy in patients with an apparently normal heart

Myocardial stunning refers to contractile dysfunction that persists after an ischemic episode and restoration of coronary blood flow. In this article, 2 cases of myocardial stunning after electroconvulsive therapy in patients with an apparently normal heart are presented. The incidence of this condition is unknown. It is observed that this condition seems to occur in females and in the obese and is generally associated with rapid recovery. This occurrence seems to be brought about by autonomic changes that occur during electroconvulsive therapy. Several drugs have been used to ameliorate the condition, although studies were limited to establish efficacy of regimens.

Electroconvulsive therapy, brain-derived neurotrophic factor, and possible neurorestorative benefit of the clinical application of electroconvulsive therapy

Treatment-resistant depression (TRD) is a growing problem in psychiatry. A recent meta-analysis has estimated TRD to be as high as 40%. Just over a decade ago, TRD was estimated to be as low as 10% to 15%. The causes of TRD are not fully understood. Finding ways to bring patients to remission faster may be part of the solution, but increasing our understanding of how depression works and how the brain responds to treatment may shed some light on this growing problem. Patients with TRD have been shown to have decreased volumes in gray matter structures, particularly in the hippocampus. Hippocampal volumes are correlated with decreased expression of neurotrophic factors (most notably, brain-derived neurotrophic factor [BDNF]), and decreased expression of BDNF correlates with the presence of depression. Increased expression of BDNF has a strong association with increased volumes in the hippocampus. Electroconvulsive therapy (ECT), a safe and effective treatment of severe depression, has been shown to be effective in TRD. Patients who undergo ECT have also had measurable increases in BDNF, indicating that ECT may be modulating intracellular processes in the patients with depression. Taken together, ECT may have a positive effect on restoring gray matter volume in patients with depression and especially TRD.

Postictal cardiovascular response predicts therapeutic efficacy of electroconvulsive therapy for depression

Physiological parameters such as blood pressure (BP) and heart rate (HR) reflect autonomic response after seizure and may correlate with therapeutic efficacy in electroconvulsive therapy (ECT). However, the literature has been inconclusive with regard to the relationship between the effectiveness of ECT and physiological markers without atropine. In a consecutive sample of 24 patients with a drug-resistant major depressive episode who underwent modified sine or pulse wave ECT without atropine, the correlation was examined between BP and HR before, and 2 min after electrical stimulation and therapeutic efficacy on depressive symptoms. When mode of stimulation (sine wave or pulse wave) and baseline Hamilton Rating Scale for Depression (HRSD) were controlled for, postictal diastolic BP, systolic BP, HR and rate pressure product (RPP) were all found to be significant predictors of post-treatment HRSD. When these predictors were entered into stepwise regression, both postictal systolic BP and HR remained as significant predictors. The higher these postical physiological parameters, the more effective the course of ECT. It may be useful to examine such sensitive physiological parameters as BP, HR or RPP to determine effective or non-effective electrical seizure.

Safety and feasibility of magnetic seizure therapy (MST) in major depression: randomized within-subject comparison with electroconvulsive therapy

Magnetic seizure therapy (MST) is a novel means of performing convulsive therapy using rapidly alternating strong magnetic fields. MST offers greater control of intracerebral current intensity than is possible with electroconvulsive therapy (ECT). These features may result in a superior cognitive side effect profile for MST, while possibly retaining the efficacy of ECT. The objective of this study was to determine whether MST and ECT differ in seizure characteristics, and acute objective and subjective cognitive side effects. A total of 10 inpatients in a major depressive episode referred for ECT were enrolled in this randomized, within-subject, double-masked trial. Seizure threshold was determined with MST and ECT in the first two sessions of a course of convulsive therapy, with order randomized. The remaining two sessions consisted of suprathreshold stimulation with MST and ECT. A neuropsychological battery and side effect rating scale were administered by a masked rater before and after each session. Tonic-clonic seizures were elicited with MST in all patients. Compared to ECT, MST seizures had shorter duration, lower ictal EEG amplitude, and less postictal suppression. Patients had fewer subjective side effects and recovered orientation more quickly with MST than ECT. MST was also superior to ECT on measures of attention, retrograde amnesia, and category fluency. Magnetic seizure induction in patients with depression is feasible, and appears to have a superior acute side effect profile than ECT. Future research will be needed to establish whether MST has antidepressant efficacy.

Cardiovascular response during ECT: a cross-over study across stimulus conditions

This study examined the effect of stimulus conditions on rate pressure product (RPP) during ECT. Seizure duration as well as baseline, ictal, and postictal RPP were recorded in 28 patients who received ECT under four stimulus conditions (unilateral threshold, unilateral suprathreshold, bilateral threshold, and bilateral suprathreshold). Seizure duration did not differ between the stimulus conditions. RPP significantly rose from baseline under every stimulus condition. Both ictal and postictal RPP values were different between stimulus conditions (one-way repeated-measure analysis of variance). Pair-wise comparisons showed that unilateral threshold ECT produced significantly lower RPP than unilateral suprathreshold and bilateral suprathreshold ECT conditions. The selective differences in RPP during ECT as well as their correspondence with the known therapeutic potency of ECT under these stimulus conditions suggest that RPP may be a potential index of ECT's therapeutic potency.

Is oral clonidine effective in modifying the acute hemodynamic response during electroconvulsive therapy?

Clonidine decreases the stress-induced sympathoadrenal responses to painful stimuli and improves hemodynamic stability during general anesthesia. Because acute hypertensive responses are often observed immediately after electroconvulsive therapy (ECT), we designed a prospective, randomized, placebo-controlled, cross-over study to assess the effects of four different oral doses of clonidine (0.05-0.3 mg per os) on the acute hemodynamic response to ECT. Anesthesia was induced with methohexital 1 mg/kg followed by succinylcholine, 1.3 mg/kg i.v. A total of 110 treatments were evaluated in 22 patients. Noninvasive mean arterial pressure (MAP) and heart rate (HR) values, duration of motor and electroencephalographic (EEG) seizure activity, and recovery times were recorded. Clonidine produced a dose-related decrease in MAP before and after ECT. Although clonidine 0.2-0.3 mg per os decreased the peak MAP value after ECT, the changes in MAP from the prestimulation values were similar in all treatment groups. Clonidine produced no significant changes in HR, duration of motor and EEG seizure activity, or recovery times after anesthesia. These data suggest that clonidine decreases the peak MAP value after ECT by decreasing MAP immediately before the ECT stimulus.

IMPLICATIONS

Oral clonidine (0.2-0.3 mg) decreases the acute hypertensive response after electroconvulsive therapy; however, this antihypertensive effect was achieved by decreasing the blood pressure before the electrical stimulus.

Seizure-induced c-fos expression in rat medulla oblongata is not dependent on associated elevation of blood pressure

This study was performed to determine whether c-fos immunoreactivity (IR) induced in medulla oblongata by pentylenetetrazole seizures is a consequence of seizure-associated blood pressure elevation and activation of baroreceptor afferent pathways, or occurs independently of hypertension. Immunohistochemical study of sections of medulla oblongata revealed that seizures are followed by induction of c-fos IR in nucleus tractus solitarius (NTS), dorsal motor nucleus of the vagus (DMN 10), and ventrolateral medulla (VLM), while there is negligible c-fos IR after saline sham injections. Seizures were associated with blood pressure elevation peaking at 31 +/- 17% (+/- SD) above baseline. Experimental hypertension at a similar level induced by i.p. phenylephrine also resulted in induction of c-fos IR in NTS. When seizures were preceded by antihypertensive treatment with the alpha-adrenergic antagonist, phentolamine, peak blood pressure tended to remain near the baseline level and lower than sham-injected controls. Normotensive seizures were associated with c-fos IR in NTS, DMN 10, and VLM similar to the pattern following hypertensive seizures. Seizure-induced activation of c-fos IR occurred despite normal blood pressure, and thus can be attributed to a direct effect of the seizure, and not to an indirect effect mediated by hypertension.

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.

Electroconvulsive therapy

The following position paper was approved by the Board of Directors of the Canadian Psychiatric Association on September 15,1992.

Cardiovascular response to unilateral electroconvulsive therapy

Few studies have examined the cardiovascular response to pulse unilateral electroconvulsive therapy (ECT) performed using modern techniques. In this study of 30 patients (mean age 62 years) with major depression, we determined the effects of pulse unilateral ECT on cardiac work load using the rate-pressure product (RPP), a product of pulse and systolic blood pressure. The mean RPP across all ECT treatments increased by an average of 96% from pre-ECT baseline, with the maximal RPP occurring typically during the seizure. The amount of increase in RPP did not differ significantly over the course of treatments. The increase in RPP was significantly and inversely related to baseline RPP, such that subjects with the highest baseline RPPs actually had smaller increases in RPP during the ECT treatments. The mean percent change in RPP was not associated with age, sex, presence of cardiovascular disease, ECT stimulus charge, EEG seizure duration, or amnestic side effects. There was a trend (p = 0.06), however, for the mean increase in RPP to be greater in responders (100% increase, n = 25) than in nonresponders (76% increase, n = 5). The potential relationship of clinical outcome to the increase in RPP suggests that both factors may be manifestations of the physiological intensity of the ECT-induced seizure.

Correlation between EEG and heart rate variation in deep enflurane anaesthesia

Variations in heart rate during deep enflurane anaesthesia were studied in 11 women admitted for elective surgery. Correlation was found between heart rate variations and bursts and suppressions in the EEG patterns. The onset of bursts coincided with accelerating heart rate, and the onset of suppressions was combined with a fall in heart rate in all patients. The correlation is not explained by ventilation arrhythmia. Both the cortical electrical activity and heart rate fluctuation are probably controlled by the same subcortical factor.

Which depressed patients will respond to electroconvulsive therapy? The search for biological predictors of recovery

A small yet significant minority of contemporary patients with endogenous depressive illness who are treated with electroconvulsive therapy (ECT) gain little or no benefit. It is argued that the use of clinical features alone may not improve the ability to predict outcome after ECT. Many biological measures have been used to attempt to identify depressed patients for whom ECT would be an effective treatment, but none has yet been shown to be superior to clinical predictors. Depressed patients show a wide range of physiological responses to the first treatment of a course of ECT. Of these physiological responses, estimations of seizure threshold and of the release of posterior pituitary peptides merit further investigation as putative predictors of recovery.