Our experience with the use of five new
antiarrhythmic drugs for treating life-threatening arrhythmias in children will be briefly reviewed. Prevention of recurrent episodes of
atrial flutter with
digoxin and
local anesthetic antiarrhythmic drugs often is only moderately successful, benefiting 65% of patients.
Amiodarone is particularly useful for those patients who cannot be controlled on this regimen. We caution that the heart rate be monitored carefully when
therapy with
amiodarone is initiated in patients likely to have
sick sinus syndrome. We have found
mexiletine useful for controlling significant ventricular arrhythmias in patients with
congenital heart disease. Likewise, 79% (11 of 14) of patients with
ventricular tachycardia treated with
amiodarone were well controlled. However, the range of disease categories (
congenital heart disease,
myocarditis,
cardiomyopathy) in which
amiodarone is effective is much broader than for
mexiletine. Although other investigators have used
amiodarone successfully for controlling
supraventricular tachycardia in the
Wolff-Parkinson-White syndrome or secondary to concealed accessory AV connections, we recommend surgical ablation.
Propafenone has significantly improved our ability to control postoperative JET. Although JET is self-limited in duration and spontaneously remits, it frequently produces life-threatening hemodynamic compromise in the postoperative setting.
Propafenone slows the ventricular rate into a range in which AV sequential pacing may be instituted. Generally, after 24 to 72 hours, the patient may be quickly weaned from
propafenone. Chronic incessant
supraventricular tachycardia (SVT) is frequently associated with a
dilated cardiomyopathy. The two most common mechanisms of incessant SVT are PJRT and
AET. We have found
encainide and
ethmozine extremely effective in suppressing
tachycardia episodes in PJRT and
AET, respectively. Medical
therapy has been associated with few side effects.