Amiodarone Induced Thyrotoxicosis in the Setting of End Stage Cardiomyopathy

Amiodarone is a class III antiarrhythmic agent which has effects of myocardial depolarization and repolarization. Due to its many side effects including thyroid dysfunction, its use is limited to life-threatening arrhythmias. The thyrotoxicosis can be from the iodine content of amiodarone or its direct toxicity on the thyroid gland. Because of the long half-life, causing amiodarone to have effects for months, medical management can be challenging, and thyroidectomy may be indicated. This is a 76-year-old man with a history of systolic heart failure with reduced ejection fraction (15%), on milrinone after cardiac resynchronization therapy, and recurrent ventricular tachycardia on amiodarone. He was admitted after his ICD device fired. During initial admission, his TSH was <0.015mcunit/mL and FT4 was 2.34ng/dL. Due to concern for amiodarone induced thyrotoxicosis (AIT), he was started on methimazole, prednisone, and cholestyramine. FT4 decreased from 2.34ng/dL to 2.23ng/dL and he discharged on methimazole 30mg daily and prednisone 20mg daily with plans to taper. He was seen outpatient with continued improvement in his FT4 to 2.09ng/dL. He was then seen again and found to have a rising FT4 to 2.22ng/dL and his regimen of prednisone was reinitiated at 10mg daily and methimazole increased to 40mg daily. Despite the medication changes, he continued to have an elevation in his FT4 up to 3.00ng/dL at which point he returned to the hospital for further evaluation and was given methimazole 60mg TID, prednisone 20mg daily, and restarted cholestyramine. With his significant cardiovascular risk, aggressive medical management was attempted prior to surgical evaluation. After his thyroid function failed to respond to medical intervention, multidisciplinary discussion was had with patient, family, and physician teams regarding surgical intervention versus continued long-term monitoring. Family elected to pursue surgery. Thyroidectomy was performed by an experienced endocrine surgeon successfully and his FT4 and T3 decreased appropriately requiring him to be initiated on levothyroxine supplementation. AIT can be separated into Type I, in which there is an increase in synthesis of T4 and T3 with amiodarone providing increasing substrate, and Type II in which there is destructive thyroiditis, releasing excess T4 and T3. In the United States, approximately 5% of individuals who are on amiodarone therapy develop hyperthyroidism, majority being Type II. If possible, amiodarone should be discontinued in Type I AIT, but there is no clear evidence for discontinuation in Type II. Medical management includes thionamides for Type I AIT and glucocorticoids for Type II AIT. Patients who are refractory to drug therapy should be treated with thyroidectomy. The advantages of a surgical procedure with careful cardiovascular monitoring overall outweigh the morbidity and mortality of uncontrolled thyrotoxicosis.

Pathophysiological Complexity of Amiodarone-Induced Hypothyroidism (AIH) in patient With Congenital Heart Disease- Ebstein Anomaly: a case report

Background: Amiodarone is a class III antiarrhythmic drug, used for the threatment of life threatening supraventricular and ventricular tachyarrhythmias and widely used in prevention of life threatening tachyarrhythmia in adults with congenital heart disease. Thyroid dysfunction is a potentially serious complication of amiodarone therapy, especially in older patients with acquired heart disease. Cause there is no published systematic study on amiodarone-associated hypothirodism in patients with congenital heart disease, we report the case of a patient with Ebstein anomaly, a rare congenital heart disorder, who developed hypothyroidism after prolonged amiodrone therapy. We report a possible pathophysiological link of amiodarone-induced hypothyroidism in a patient with rare congenital heart disease, that has not been reported in a significant number in the literature so far.Case presentation: A female, 55-year-old patient with history of Ebstein anomaly (non operated), presented to a family medicine doctor with symptoms of progressive dyspnoea, fatigue and dysfagia for several months. Electrocardiography, echocardiography and chest X- ray confirmed presence of Ebstain anomaly. Laboratory results (including thyroid hormone values) and thyroid ultrasound were performed which confirmed the presence of hypothyroidism.Conclusions: According to available data, there is no published systematic study on amiodarone-associated hypothirodism in patients with congenital heart disease (large cohort studies). Pathophysiological complexity, however, could be due to the agent triggering autoimmune thyroid disease, so it is possible that amiodarone precipitated the onset of preexisting autoimmune disease. The value of regular thyroid function testing and measurement of thyroid antibodies should be considered in patients during amiodarone administration, especially in older patients with rare congenital heart disease.

Efficacy of amiodarone in the treatment of ventricular arrhythmias in patients with coronary artery disease in Bangladesh

Background: Ventricular arrhythmias (VA) are among the most feared complications of coronary artery disease (CAD) and one of the major contributors of death in CAD patients. Antiarrhythmic drug (AAD) therapy is required for recurrent significant VA in the absence of need for further revascularization. But all AADs do not have the same efficacy against life threatening VA and supraventricular arrhythmias (SVAs). Methodology: All (50) patients admitted in the department of Cardiology, BSMMU with ventricular arrhythmias with CAD fulfilling the inclusion and exclusion criteria were included in the study. Informed written consent was taken from each patient before enrollment. Detailed history was taken and relevant physical examinations were done. Loading dose followed by maintenance dose of amiodarone was given and recorded. Relevant lab investigations were performed and recorded in predesigned semi-structured data collection sheet. Symptomatic improvement was assessed, relevant physical examination was done and lab investigations were performed at 1, 3 and 6 month follow up. After editing data analysis was carried out by using the Statistical Package for Social Science (SPSS) version 23.0 windows software. Results: The mean age was found 57.7±8.0 years with a range of 45 to 78 years. Almost two third (62.0%) patients were male and 19(38.0%) patients were female. Male female ratio was 1.6:1. Almost three fourth (74.0%) patients had chest pain, 15(30.0%) had palpitation and 11(22.0%) had shortness of breath. Two third (66.0%) patients had hypertension, 23(46.0%) had dyslipidemia, 17(34.0%) had smoking and 9(18.0%) had diabetes mellitus. Twenty nine (58.0%) patients had family history of IHD. The difference was statistically significant (p<0.05) when compared to baseline. Regarding arrhythmia, 45(90.0%) patients was found to have PVC in baseline and 3(6.4%) at 6th month. The reduction of PVC and VT at six month were statistically significant (p<0.05) when compared to baseline. Regarding outcome 2(4.1%) patients died, one patient dropped out due to thyroid dysfunction and 47 were alive. Conclusion: In conclusion it was found that different forms of ventricular arrhythmias like PVCs, VT were significantly reduced gradually with amiodarone therapy at 6th month follow up. J Dhaka Medical College, Vol. 29, No.2, October, 2020, Page 158-164

Comparing the Clinical Effects of Amiodarone and Propafenone in the Arrhythmia’s Treatment

Objective: To compare the clinical effects of Amiodarone and Propafenone in the treatment of arrhythmia. Methods: Choose our hospital 100 cases of patients with cardiac arrhythmias. We shall divided into control group (50 cases, Propafenone treatment) and treatment group (50 cases, Amiodarone therapy), to collect the curative effect of two groups of patients, adverse reactions, nausea and vomiting, dizziness, headache, low blood pressure, heart rate slow down) in accordance with the drug treatment and electrocardiogram (ecg) changes before and after the treatment (PR interphase, QT interphase, QRS duration). Results: Control group and the clinical curative effect of treatment group total effectiveness 98%, 86% respectively, the treatment group is significantly higher than the control group. Control group and treatment group the incidence of adverse reactions were 4%, 12%, treatment group was significantly lower than the control group, and two groups of patients duration are improved after treatmentstage PRinterval and QT, QRS.But the treatment group patients with stage PRinterval and QT,such as electrocardiogram QRS duration change was better than control group, which difference hasstatisticalsignificance (P &lt; 0.05). Conclusion: Compared with propafenone, amiodarone in the treatment of arrhythmia patients has better therapeutic effect and higher safety, and improve the clinical symptoms of patients effectively. It is suggested to promote clinical practice.

Abstract 16548: Low-dose Amiodarone for Control of Atrial Fibrillation (AF) Remains Effective in Patients With Ejection Fraction Less Than 50%

Introduction: Our previous work has shown low-dose Amiodarone (often less than 600 mg per week) is effective for control of AF in a forced down-titration schema. Many studies have shown restoration of sinus rhythm in patients with CHF shows promise for reduced mortality and morbidity. This analysis compares results of this protocol in patients with ejection fraction above and below 50%. Methods: Consecutive patients with atrial fibrillation deemed suitable for Amiodarone therapy were prospectively followed with a forced down-titration protocol. Controlled atrial fibrillation was defined as an AF burden of less than 1% on device diagnostics (30% of patients) or no symptoms and sinus rhythm on clinical visit EKGs. Demographic and clinical data were analyzed for patients with ejection fraction above and below 50%. Results: Patients with EF less than 50% had greater success (35/38) or 92% than patients with ejection fraction greater than 50% (39/51) or 76%. However, patients with ejection fraction under 50% required larger doses. See graph for detailed doses. Overall success was good in both groups with no sustained side effects. Conclusions: Amiodarone in low doses is effective in control of atrial fibrillation in patients across the spectrum of ejection fractions. Lower ejection fractions may require a somewhat higher dose (less than 1000 mg per week) but at a higher success rate.Larger studies could potentially show the impact of this protocol on mortality.

Amiodarone-associated thyroid dysfunction in adult patients with congenital heart disease: a nationwide health insurance data analysis including >50.000 individuals

Background Arrhythmias are common in adult patients with congenital heart disease (ACHD). Amiodarone is widely used as an antiarrhythmic agent. Thyroid dysfunction represents a serious complication of amiodarone treatment. Systematic data on the prevalence of thyroid dysfunction, risk factors for complications and treatment options are lacking. Purpose Based on data from one of the largest German Health Insurance Companies (BARMER GEK, approx. 9 million members), we performed a retrospective analysis investigating the rate of thyroid complications under active amiodarone therapy in ACHD patients and a comparison group of cardiac patients without congenital heart disease on amiodarone between 2005 and 2018. Result Overall, 910 ACHD (34% female; median age 66 y; CHD complexity mild, moderate, severe in 64.6%, 23.6%,11.8%, respectively) and 49,782 non-ACHD patients (37% female, median age 73.4 y) received prescriptions for amiodarone without documented pre-existing thyroid disease or use of thyroid medication. Over a treatment period of 184,770 patient-years, 10,874 incidents of thyroid dysfunction occurred in the non-ACHD and 201 in the ACHD cohort, corresponding to an event-rate of 6% and 5.3% per patient year, respectively. Overall, 23.5% of the ACHD patients developed thyroid dysfunction (56.71% hypothyroidism, 43.3% hyperthyroidism). Risk factors for developing thyroid dysfunction on time dependent Cox-analysis were female gender (hazard ratio [HR] 1.44, 95% CI: 1.39–1.50; p&lt;0.001), lower patient age (HR: 0.96 per 10 years, 95% CI: 0.94–0.98, p&lt;0.001) renal dysfunction (HR 1.24, 95% CI: 1.19–1.29, p&lt;0.001), history of alcohol abuse (HR 1.17, 95% CI: 1.07–1.27, p,0.001) and smoking (HR 1.12, 95% CI: 1.06–1.19, p&lt;0.001). Congenital heart disease itself was not associated with a higher risk of thyroid dysfunction (HR 0.96, 95% CI: 0.83–1.10, p=0.53). Within the ACHD group, patients with complex disease had a significantly higher risk of thyroid dysfunction (HR 1.5, 95% CI: 1.00–2.25, p=0.049) compared to patients with simple diagnoses. Once thyroid disease occurred, 48.5% of patients were continued on amiodarone therapy, 12.8% of patients underwent an electrophysiologic procedure and only 2.1% of patients received class I antiarrhythmics. Specific thyroid therapy included thyroxine (62.6% of hypothyroid patients) or thiamazole (22.6% of hyperthyroid patients). Only 2.3% of patients required surgery or radiotherapy within 6 months after thyroid dysfunction. Conclusion Amiodarone-associated thyroid dysfunction is a frequent complication in ACHD patients. Overall, one in 4 ACHD patients on amiodarone developed thyroid dysfunction in our study. In itself, ACHD does not seem to increase the risk of thyroid dysfunction. However, female gender, complexity of disease, younger age and renal dysfunction emerged as independent risk factors. When amiodarone therapy can not be avoided, close follow-up and regular thyroid function tests are recommended. Funding Acknowledgement Type of funding source: None