Amiodarone tachydysrhythmias

In a comparison of amiodarone (n = 23) with sotalol (n = 22) in patients with spontaneous sustained ventricular tachydysrhythmias secondary to myocardial infarction, sotalol was much more effective, 75% of those taking it remaining free of dysrhythmias compared with 38% of those taking amiodarone (34). Adverse effects requiring withdrawal occurred in 17% of those taking amiodarone at a median time of 3.5 months. The adverse effects included malaise, rash, headaches, flushing, and dyspnea due to pulmonary fibrosis. 

Interactions of mexiletine with other cardioactive drugs have been reviewed (48). The most important are beneficial interactions with beta-adrenoceptor antagonists, quinidine, and amiodarone in the suppression of ventricular tachydysrhythmias. During these interactions the... 

Observational studies In a 10-year prospective study of the effects of the timing of the introduction of amiodarone after corrective surgery for congenital heart defects, 71 of 2651 patients (2885 procedures, 2106 cardiopulmonary bypass procedures) received amiodarone for newly detected postoperative atrial tachydysrhythmias (n = 70) or ventricular tachydysrhythmias (n = 7) as early treatment (i.e. within 60 minutes from detection n = 29) or late treatment (i.e. after 60 minutes from detection n = 42) [21 ]. There were significant benefits of early treatment for time to rate and rhythm control, reduction in the dose needed to obtain rate control, and reduction of pediatric cardiac intensive care stay. No adverse events in either group required additional catecholamine therapy, additional fluids, or resuscitation. 

In a retrospective study of the potential for major adverse cardiovascular events in 57 patients with amiodarone-induced thyrotoxicosis compared with 224 euthyroid patients for a mean of 49 months, the patients with thyrotoxicosis had a higher rate of events (32% versus 11%), mostly driven by a higher rate of ventricular tachydysrhythmias requiring admission (7.0% versus 1.3%) overall, there was a 2.7 times increased risk [26 ]. Thyrotoxicosis (HR = 2.68) and a left ventricular ejection fraction below 45% (HR = 2.52) were independent predictors of major adverse cardiovascular events. 

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