Heart rate for prediction of complications following tricyclic antidepressant overdose
Date First Published:
June 16, 2008
Last Updated:
November 17, 2010
Report by:
Rick Body, NIHR Clinical Lecturer (Manchester Royal Infirmary)
Search checked by:
Angela Coumbarides, Manchester Royal Infirmary
Three-Part Question:
In [patients who have taken an overdose of tricyclic antidepressants] is [heart rate] a [predictor of death, arrhythmias and seizures]?
Clinical Scenario:
A forty year-old homeless man presents to the Emergency Department claiming to have taken ten of his dothiepin tablets two hours ago.
His ECG shows normal QRS duration and normal QRS axis, his blood pressure is 130/85 and he is fully conscious. He therefore appears to be at low risk of complications but his heart rate is 110 beats per minute. You wonder if this is a useful predictor of complications.
His ECG shows normal QRS duration and normal QRS axis, his blood pressure is 130/85 and he is fully conscious. He therefore appears to be at low risk of complications but his heart rate is 110 beats per minute. You wonder if this is a useful predictor of complications.
Search Strategy:
Ovid Medline 1950 - 2008 June Week 1
Ovid Embase 1980 - 2008 Week 24
Ovid Embase 1980 - 2008 Week 24
Search Details:
(exp Antidepressive Agents, Tricyclic/ or tricyclic.mp. or amitriptyline.mp. or exp Amitriptyline/ or desipramine.mp. or exp Desipramine/ or clomipramine.mp. or exp Clomipramine/ or doxepin.mp. or exp Doxepin/ or dothiepin.mp. or exp Dothiepin/ or imipramine.mp. or exp Imipramine/ or lofepramine.mp. or exp Lofepramine/ or nortriptyline.mp. or exp Nortriptyline/ or trimipramine.mp. or exp Trimipramine/) AND (exp Overdose/ or exp Poisoning/ or overdose.mp. or exp Drug Overdose/) AND (exp Heart Rate/ OR exp Tachycardia/ OR exp Tachycardia, Sinus/ OR (tachycardi$ or heart rate).mp.) limit to human(s) and English language
Outcome:
547 papers were identified (439 in Embase and 108 in Medline). 7 were relevant to the three-part question.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| The limited utility of electrocardiography variables used to predict arrhythmia in psychotropic drug overdose Buckley,Nicholas; Chevalier,Stephan; Leditschke,I.Anne; O''Connell,Dianne; Leitch,James; Pond,Susan 2003 Australia | 39 patients with serious arrythmias (VT, SVT or cardiac arrest) after TCA overdose or thioridazine overdose compared with 117 controls with clinically significant overdose matched to each case for the drug ingested. | Case control study | Case control design suboptimal Prospective observational cohort would have been a superior design Seizures and death not included as outcomes. |
||
| Demographic and electrocardiographic factors associated with severe tricyclic antidepressant toxicity Caravati EM, Bossart PJ 1991 | ED overdose patients with a positive serum drug screen for TCA and an available 12-lead ECG 65 had signs of major toxicity (coma, seizures, arrhythmias needing treatment, need for intubation or death 41 had only minor signs of toxicity |
Retrospective analysis | Heart rate ≥120bpm for prediction of membership to major toxicity group | Odds ratio 2.86 (P<0.05) | Retrospective |
| Value of initial ECG findings and plasma drug levels in cyclic antidepressant overdose Lavoie FW, Gansert GG, Weiss RE 1990 United States | 187 patients who were admitted to ICU with overdose and tested positive for TCA | Retrospective analysis | Heart rate ≥100bpm among patients with seizures | 4/6 (67%) had heart rate ≥100bpm | Retrospective Very small numbers with complications Only dichotomous outcome of heart rate ≥100bpm assessed as predictor |
| Heart rate ≥100bpm among patients with arrhythmias or death | 3/3 (100%) had heart rate ≥100bpm | ||||
| Heart rate ≥100bpm among patients without complications | 121/178 (67%) had heart rate ≥100bpm | ||||
| Level of consciousness as a predictor of complications following tricyclic overdose Emerman CL, Connors AF, Burma GM 1986 United States | All 92 patients age ≥17 years who were admitted to Cleveland Metropolitan General Hospital with TCA overdose between 1975 and 1985. | Retrospective analysis | Mean heart rate in patients with and without complications (hypoventilation, loss of protective | 102 +/- 20 (no complications) vs. 115 +/- 21 (with complications), P<0.01 | Retrospective 38 patients had a mixed drug overdose (although subgroup analysis of patients with pure TCA overdose yielded similar results) Only 92 patients included over a 10 year period. |
| Multivariate logistic regression model to predict complications | Only GCS was a significant independent predictor of complications | ||||
| Tricyclic antidepressant overdose: emergency department findings as predictors of clinical course Foulke GE, Albertson TE, Walby WF 1986 | 165 patients who presented to the ED following antidepressant overdose | Retrospective analysis | Patients with isolated finding of sinus tachycardia | No complications | Retrospective |
| Recovery from a psychotropic drug overdose tends to depend on the time from ingestion to arrival, the Glasgow Coma Scale, and a sign of circulatory insufficiency on arrival Yanagawa Y, Sakamoto T, Okada Y 2007 Japan | 175 patients who were intubated following psychotropic drug overdose between January 2000 and December 2005 Patients were divided into an “early group” (extubated within 2 days) and a late group (not extubated within 2 days) | Retrospective analysis | Mean heart rate (SE) in early and late groups | 92.6 +/- 1.9 (early group) vs. 107 +/- 4.1 (late group), P=0.001 | Retrospective Significant selection bias: only intubated patients included No analysis of different GCS cut-offs for prediction of late extubation |
| Multivariate logistic regression model to identify independent predictors of late extubation | Heart rate was an independent predictor (OR 1.02, 95% CI 1.00-1.03, P=0.01) |
Author Commentary:
Sinus tachycardia is a common finding in patients with TCA overdose, with studies quoting figures from 40.7% to 88% (Rudorfer 1919;Unverir R et al. 2006). Further, tabulated data suggest that the absence of tachycardia does not preclude the occurrence of serious complications. On multivariate analysis only Yanagawa et al (Yanagawa Y, Sakamoto T, & Okada Y 2007) found that heart rate was an independent predictor of adverse outcome (late extubation among intubated patients).
However a series of retrospective analyses have found that increased heart rate is associated with an increased risk of complications following TCA overdose, including death, arrhythmias, seizures, coma and hypotension. Petit et al found that patients with higher serum TCA levels were significantly more likely to have a heart rate >120bpm (P<0.01)(Petit et al. 1977). Caravati et al found that a heart rate ≥120bpm carried an odds ratio of 2.86 for the prediction of complications.
While other clinical findings (including Glasgow Coma Scale and QRS duration) appear to be stronger predictors of complications than heart rate and should be used preferentially to identify high risk patients and to guide therapy, patients with significant sinus tachycardia should be carefully monitored for the occurrence of complications. Given the potential risk of arrhythmias this should include ECG monitoring.
However a series of retrospective analyses have found that increased heart rate is associated with an increased risk of complications following TCA overdose, including death, arrhythmias, seizures, coma and hypotension. Petit et al found that patients with higher serum TCA levels were significantly more likely to have a heart rate >120bpm (P<0.01)(Petit et al. 1977). Caravati et al found that a heart rate ≥120bpm carried an odds ratio of 2.86 for the prediction of complications.
While other clinical findings (including Glasgow Coma Scale and QRS duration) appear to be stronger predictors of complications than heart rate and should be used preferentially to identify high risk patients and to guide therapy, patients with significant sinus tachycardia should be carefully monitored for the occurrence of complications. Given the potential risk of arrhythmias this should include ECG monitoring.
Bottom Line:
Heart rate appears to be a significant predictor of complications following TCA overdose, although it has questionable additive value when other clinical findings (including Glasgow Coma Scale and QRS duration) are taken into account.
Level of Evidence:
Level 3: Small numbers of small studies or great heterogeneity or very different population
References:
- Buckley,Nicholas; Chevalier,Stephan; Leditschke,I.Anne; O''Connell,Dianne; Leitch,James; Pond,Susan. The limited utility of electrocardiography variables used to predict arrhythmia in psychotropic drug overdose
- Caravati EM, Bossart PJ. Demographic and electrocardiographic factors associated with severe tricyclic antidepressant toxicity
- Lavoie FW, Gansert GG, Weiss RE. Value of initial ECG findings and plasma drug levels in cyclic antidepressant overdose
- Emerman CL, Connors AF, Burma GM. Level of consciousness as a predictor of complications following tricyclic overdose
- Foulke GE, Albertson TE, Walby WF. Tricyclic antidepressant overdose: emergency department findings as predictors of clinical course
- Yanagawa Y, Sakamoto T, Okada Y. Recovery from a psychotropic drug overdose tends to depend on the time from ingestion to arrival, the Glasgow Coma Scale, and a sign of circulatory insufficiency on arrival
- Petit JM, Spiker DG, Ruwitch JF, Ziegler VE, Weiss AN, Biggs JT.. Tricyclic antidepressant plasma levels and adverse effects after overdose.
- Unverir R, Atilla R, Karcioglu O, Topacoglu H, Demiral Y, Tuncok Y. A retrospective analysis fo antidepressant poisonings in the Emergency Department: 11-year experience
- Rudorfer MV. Cardiovascular changes and plasma drug levels after amitriptyline overdose