Comparison of the cardiovascular effects of amitriptyline and zimelidine using thoracic impedance cardiography

Impact of antidepressant use on the autonomic nervous system: A meta-analysis and systematic review

Changes in cardiac autonomic nervous system (ANS) regulation observed in psychiatric disorders may be mitigated by antidepressants. We meta-analyzed and systematically reviewed studies examining antidepressants' effects on ANS outcomes, including heart rate variability (HRV). We conducted a PRISMA/MOOSE-compliant search of PubMed and Scopus until March 28th, 2022. We included randomized placebo-controlled trials (RCTs) and pre-post studies, regardless of diagnosis. We pooled results in random-effects meta-analyses, pooling homogeneous study designs and outcomes. We conducted sensitivity analyses and assessed quality of included studies. Thirty studies could be meta-analyzed. Selective serotonin reuptake inhibitors (SSRIs) were significantly associated with a reduction in the square root of the mean-squared difference between successive R-R intervals (RMSSD) (SMD= -0.48) and skin conductance response (SMD= -0.55) in RCTs and with a significant increase in RMSSD in pre-post studies (SMD=0.27). In pre-post studies, tricyclic antidepressants (TCAs) were associated with a significant decrease in several HRV outcomes while agomelatine was associated with a significant increase in high frequency power (SMD= 0.14). In conclusion, SSRIs reduce skin conductance response but have no or inconclusive effects on other ANS outcomes, depending on study design. TCAs reduce markers of parasympathetic function while agomelatine might have the opposite effect. Studies are needed to investigate the impact of SSRIs on the recovery of cardiac ANS regulation after acute myocardial infarction, and the effects of newer antidepressants.

Comparison of cardiac output measurements by thermodilution and thoracic electrical bioimpedance in critically ill versus non-critically ill patients

Thoracic electrical bioimpedance (TEB) has been proposed as an alternative to thermodilution (TD) for the measurement of cardiac output in settings such as the Emergency Department where invasive monitoring is not available. Validation studies comparing TEB with TD suggest a wide range of variability in the agreement between the two methods. This prospective study tests the hypothesis that this variability may be related to the severity of patient illness. Fifteen non-critically ill patients undergoing cardiac catheterization and 13 critically ill patients who underwent Swan-Ganz catheterization in the medical intensive care unit (MICU) were enrolled. Fifty-one pairs of data from the catheterization laboratory and 49 pairs of data from the MICU were obtained. The patients were graded retrospectively according to the APACHE II scoring system. The mean difference (bias) between TEB and TD results was calculated for each patient using the method suggested by Bland and Altman. A pooled t-test was performed to determine whether there was any significant difference between the APACHE II scores or cardiac output measurements obtained by TEB and TD in the two groups. APACHE II scores were 4.7 +/- 1.2 for the catheterization laboratory and 14.2 +/- 5.0 for the intensive care unit patients (P < .001). The catheterization laboratory (cath lab) group bias was 0.23 +/- 2.19, whereas the MICU bias was .002 +/- 2.33. There was no significant difference in the bias between the two groups despite significant differences in the APACHE II scores. Standard deviations of the bias were less than 15% different from each other.(ABSTRACT TRUNCATED AT 250 WORDS)

The cardiovascular effects of antidepressants

This monograph comprises a review of the cardiovascular effects of the various types of antidepressant drugs in clinical use. The frequency, severity and clinical importance of these effects are placed in perspective. Most antidepressants can cause changes in blood pressure. Both the tricyclic type (TCA) and the monoamine oxidase inhibitors (MAOIs) can produce postural hypotension which may be dose-limiting. In addition, the MAOIs may be associated with severe hypertension when amine-containing foods or medicines are ingested. It is unlikely that therapeutic doses of any available antidepressant drug could impair cardiac contractility. Typical TCAs can cause abnormalities of cardiac conduction and arrhythmias, but this affects less than 5% of patients, mostly to a clinically insignificant extent. Newer compounds such as lofepramine, mianserin, trazodone and viloxazine seem safer in this respect. Reports of an association between therapeutic use of TCAs and sudden death are far from convincing. Overdosage with the MAOIs, lithium and carbamazepine is dangerous but not common; overdose with a TCA is a major source of morbidity and mortality. Lofepramine, mianserin and trazodone are relatively safe in overdose. The use of various antidepressants in patients with hypertension, cardiac failure, angina pectoris, myocardial infarction, or cardiac arrhythmias is discussed and guidelines suggested for the selection and use of antidepressant medication.

A double-blind, controlled evaluation of zimeldine, imipramine and placebo in patients with primary affective disorders

Zimeldine, imipramine and placebo were studied in a randomized, double-blind, parallel group comparison of 119 patients with primary affective disorders. These out-patients were between 18 and 65 years of age and all received placebo single-blind during an initial 3-7-day washout period. During the subsequent 6-week double-blind period, patients were titrated from 50 mg b.d. to 150 mg b.d. with zimeldine, a potent and selective inhibitor of 5-HT reuptake, with imipramine, an inhibitor of noradrenaline and 5-HT reuptake, or with a corresponding number of placebo capsules. The zimeldine treatment group had significantly lower mean HAM-D scale total scores than the placebo and imipramine groups at week 4 and last available assessment. There was a significantly greater proportion of patients showing an improvement of 50% or more in HAM-D score, among the zimeldine group than in the placebo group at week 4, and among the imipramine group at weeks 4, 6 and last available assessment. The Clinical Global Impression (CGI) scales and the 56-item Hopkins Symptom Check-list (HSCL-56) self-rating inventory both showed significantly more improvement in the zimeldine patients than in the placebo or the imipramine patients. Fewer zimeldine patients reported adverse experiences than imipramine patients. Dry mouth was the most frequently reported adverse experience, occurring significantly more often in the imipramine group than the zimeldine or the placebo groups; significantly more zimeldine than placebo patients reported dry mouth. Headache was the only other adverse experience which occurred more often in the zimeldine than in the placebo group. The imipramine group had consistently higher mean pulse rates than the other two groups, and postural hypotension was also more common in the imipramine group.

Zimeldine in depressive illness--efficacy and safety data

Two studies of zimeldine in depressive illness are reported, one a double-blind, placebo-controlled trial, the other an open evaluation. In both studies, zimeldine was shown to have antidepressant properties. No simple relationship between plasma zimeldine or norzimeldine and clinical effect was demonstrated in eight patients treated for 6 weeks. Minor changes in electrocardiographic parameters were noted in some zimeldine patients. Side-effects attributable to zimeldine treatment were generally of mild to moderate severity and the drug was well tolerated. During the studies, one patient overdosed on zimeldine (5.2 g) and, although plasma concentrations were excessive, minimum side-effects were recorded. Two cases of suspected adverse drug reactions with zimeldine are described.

A comparison of zimeldine and amitriptyline on cardiovascular effects in healthy volunteers

The cardiovascular effects of zimeldine (200 mg) and amitriptyline (150 mg) for 6 days were compared in a study involving 10 healthy volunteers. No significant changes were found in heart rate, mean arterial blood pressure or left ventricular contractility when patients were taking zimeldine. With amitriptyline, significant changes were seen at some point during the trial period for all these parameters. No significant changes were seen in the ECGs recorded. Thus, zimeldine appears to be free of adverse effects on contractility, but amitriptyline appears to have a negative inotropic effect.