methimazole and Tachycardia--Supraventricular

A case of a 38-year-old male with supraventricular paroxysmal tachycardia existing for more than a decade is reported. He has received amiodarone in a daily dose of 800 mg for three years and the tachycardia returned in 1992. New antiarrhythmic drugs were added but no beneficial effect has been achieved and moreover, a case of ventricular fibrillation occurred. The 12-lead ECG performed during tachycardia and the electrophysiological study showed orthodromic AV reentry tachycardia. Laboratory tests performed proved hyperthyreotic state. Attacks of paroxysmal tachycardia were returned and aggravated by the hyperthyreosis induced by amiodarone. Finally, antiarrhythmic drugs were discontinued and methimazol was introduced. Gradually, the patient become asymptomatic within two months. The most important conclusion of the case reported, that the amiodarone induced hyperthyreosis can be subclinical or obscure. Consequently, a regular control of serum thyreoid hormone levels at least twice a year on patients with long term amiodarone administration should be advised.

Topics: Adult; Amiodarone; Anti-Arrhythmia Agents; Electrocardiography; Humans; Hyperthyroidism; Male; Methimazole; Tachycardia, Atrioventricular Nodal Reentry; Tachycardia, Paroxysmal; Tachycardia, Supraventricular

In a patient chronically treated with amiodarone, subclinical iodine-induced hypothyroidism occurred as a result of excess iodine released from the amiodarone molecule. The patient was maintained on amiodarone and developed thyrotoxicosis as a result of a destructive process into the thyroid follicles. Amiodarone was withdrawn and methylprednisolone and methimazole treatment was started with resolution of the thyrotoxic phase. Months later, off therapy, the patient developed subclinical hypothyroidism. This is the first description of hypo- and hyperthyroidism in the same patient caused by amiodarone therapy. This unusual observation suggests that patients treated with amiodarone are at risk to develop hyperthyroidism even if they show laboratory findings consistent with hypothyroidism.

Topics: Amiodarone; Antibodies; Humans; Hypothyroidism; Male; Methimazole; Methylprednisolone; Middle Aged; Tachycardia, Supraventricular; Thyroglobulin; Thyrotoxicosis; Thyrotropin; Thyroxine; Triiodothyronine

There was presented a case of a therapy-resistant paroxysmal supraventricular tachycardia 130-140/min lasting about 100 days in a 21 years old barmaid drinking 5-6 glasses of natural coffee a day within last 3 years. Supraventricular tachycardia did not impair her working abilities; she was treated with propranolol within last 3 weeks before the admission to hospital. After 4 day therapy with 800 mg of quinidine, 10% potassium chloride and 75 mg of hydroxyzine performed electrocardioversion restored the sinus rhythm 90/min, but unfortunately supraventricular tachycardia returned 4 hours later. Thyroid hormones examination revealed isolated increase of serum T3 level to 3.0 ng/ml (normal value range 0.8-1, 6 ng/ml). Ultrasound examination showed mild parenchymatous goitre. Authors diagnosed a rare type of thyrotoxicosis-triiodothyronine toxicosis+, which was only manifested by long-lasting supraventricular tachycardia without clinical state impairment. Thiamazole-40 mg/day (60 mg from the 28th day of therapy), propranolol-160 mg/day as well as sedatives, 10% KCl and vitamins C and B6 were started to be given. After 72 days of treatment, when serum T3 level lowered to 2.35 ng/ml sinus rhythm 88/min returned, which was proved by 24 hour ECG Holter monitoring. The woman put on weight 10.5 kg during hospitalization and discharged from hospital to out-patient follow-up in good condition. Other authors emphasized that T3-Thyrotoxicosis did not clinically stray from the toxic multinodular or Graves-Basedow's goitre. Three year coffee overdosage deceived physicians at the start of therapy, because its abuse is a known factor inducing supraventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Drug Therapy, Combination; Electrocardiography; Female; Humans; Methimazole; Propranolol; Tachycardia, Supraventricular; Thyrotoxicosis; Triiodothyronine