Esmolol for intractable ventricular arrhythmias in major amitriptyline toxicity

A massive tricyclic overdose of 10 g of amitriptyline resulted in cardiovascular collapse with multiple episodes of ventricular tachycardia and ventricular fibrillation despite aggressive attention to current recommended therapy of sodium bicarbonate and hypertonic saline, and correction of electrolytes. Second-line antiarrhythmic therapies failed to reduce the recurrent deterioration to malignant ventricular rhythms. Progression to extracorporeal support was avoided by the use of a titrated esmolol infusion. We discuss the physiological rationale by which esmolol may prevent tachyarrhythmia and fibrillation in severe amitriptyline toxicity.

Electrocardiogram Before Tricyclic Antidepressant Use: Minimal Impact in Pediatric Functional Gastrointestinal Disorders

OBJECTIVES

The aim of this study was to determine the effect of electrocardiogram (ECG) findings on the initiation of tricyclic antidepressants (TCAs) for functional gastrointestinal disorders (FGIDs) and to evaluate cardiac outcomes related to low dose TCA use.

METHODS

We performed a retrospective chart review of all pediatric outpatients at a tertiary pediatric hospital with an ECG ordered by a pediatric gastroenterologist when considering initiation of a TCA between January 2011 and February 2018. We collected demographics, previous cardiovascular testing results, TCA dosing, and pertinent outcomes, including cardiology referrals, emergency department, and hospital admissions, and death during the study period. All ECGs were reviewed for corrected QT (QTc) interval, heart rate, and other abnormalities.

RESULTS

Of 233 patients with screening ECGs, most (84.1%) were prescribed a TCA. Functional abdominal pain or dyspepsia account for 82.0% of diagnoses. Initial TCA dosing of amitriptyline varied widely, 10-50 mg/day, and the dose was not associated with QTc intervals. TCAs were not started in only 1.7% (4/233) due to ECG results. A significant ECG abnormality prompting cardiology referral was found in eight (3.4%) with a prolonged QTc interval in one (0.4%). In 10.7% (25/233) of patients, screening ECG was obtained despite available ECG in the chart. No deaths and no emergency department or hospital visits for arrhythmia or drug overdose occurred.

CONCLUSION

Screening ECGs infrequently influence TCA initiation and may lead to increased resource utilization. The overall frequency of cardiology referral due to ECG results is low. Serious adverse cardiac events are unlikely with low dose TCA administration.

Cardioprotective Effect of Paricalcitol on Amitriptyline-Induced Cardiotoxicity in Rats: Comparison of [99mTc]PYP Cardiac Scintigraphy with Electrocardiographic and Biochemical Findings

Taking an overdose of AMT, a commonly prescribed tricyclic antidepressant drug, has an increased risk of sudden cardiac death. The cardiotoxicity of amitriptyline (AMT) is a commonly observed toxicity with high morbidity and mortality rates in emergency departments (ED). Nevertheless, there are still no effective treatment options for AMT-induced cardiotoxicity. The aim of the present study was to evaluate the effects of paricalcitol (PRC), a Vitamin D receptor agonist, using electrocardiographic (ECG), biochemical, and scintigraphic methods. Twenty-eight male Wistar rats were randomly divided into four groups: untreated control (CON), amitriptyline-induced cardiotoxicity (AMT), paricalcitol (PRC), and amitriptyline + paricalcitol (AMT + PRC). Cardiotoxicity was induced by intraperitoneal (i.p) injection of a single-dose AMT (100 mg/kg). PRC was administered as 10 μg/kg (i.p.) after the injection of AMT. We examined ECG, biochemical, and scintigraphic results of PRC administration on AMT-induced changes. Cardiotoxicity of AMT was characterized by conduction abnormalities (increased QRS complex, T wave, and QT interval duration and elevation of ST segment amplitude), elevated ^99mTechnetium Pyrophosphate ([^99mTc]PYP) uptake, and increased cardiac troponin T (cTnT) levels. Treatment with PRC significantly decreased all AMT-associated conduction abnormalities in ECG (p < 0.001), and decreased [^99mTc]PYP uptake (p < 0.001) and serum cTnT level (p < 0.001). The present study indicated that the vitamin D receptor agonist paricalcitol could decrease the AMT-induced cardiotoxicity. This suggests [^99mTc]PYP as a non-invasive method for the evaluation of myocardial injury induced by AMT. According to the results of the present study, PRC has beneficial effects on AMT-induced cardiotoxicity.

The Effects of Lipid Emulsion, Magnesium Sulphate and Metoprolol in Amitriptyline-Induced Cardiovascular Toxicity in Rats

The aim of this study was to evaluate the effects of metoprolol, lipid emulsion and MgSO₄ which can be recommended for prevention of long QT that is one of the lethal consequences of amitriptyline intoxication. Thirty Sprague-Dawley male rats were included. Five groups respectively received the following: saline intraperitoneally (i.p.); amitriptyline (AMT) 100 mg/kg per os (p.o.) and saline i.p.; AMT 100 mg/kg p.o. and 5 mg/kg metoprolol i.p.; AMT 100 mg/kg p.o. and 20 ml/kg lipid emulsion i.p.; AMT 100 mg/kg p.o. and 75 mg/kg MgSO₄ i.p. After 1 h, all groups were analysed by ECG recordings in DII lead; their blood was taken for biochemical examination and euthanasia was performed. For histological examination, cardiac tissues were removed and sections were prepared. QTc was significantly reduced in treatment groups compared to the AMT+saline group. When compared with the AMT+saline, lipid emulsion did not affect pro-BNP and troponin levels in biochemical analysis, but it significantly reduced Caspase 3 expression in histological examination. In the group treated with AMT and metoprolol, there was no significant effect on Caspase 3 expression. In MgSO₄-treated group, there was a significant decrease in troponin, pro-BNP and urea levels biochemically and significant decrease in Caspase 3 expression histologically when compared with the control group. With further studies including clinical studies, MgSO₄, lipid emulsion or metoprolol may be used to improve AMT-induced cardiotoxicity. They can possibly become alternative approaches in the future for suicidal or accidental intoxication of tricyclic antidepressant in emergency departments.