Clues may be apparent from the history, which should include questions about drugs, especially caffeine and decongestants, old myocarditis, or predisposition to electrolyte imbalance. Physical examination may show mitral valve prolapse or evidence of unsuspected congenital or acquired cardiac disease. The prognosis for a child with chronic ventricular dysrhythmia depends to a large extent on whether the patient's heart is normal or abnormal. If the above studies disclose no hemodynamic or angiographic abnormalities, treatment may be withheld unless the patient is symptomatic. All patients with an abnormal heart should undergo treatment.
Treatment includes drug therapy, surgery, and pacemaker placement.
Drugs commonly used include dilantin, propranolol, quinidine, and disopyramide. Dosages for these drugs are listed in Table 2. Dilantin is recommended as the drug of choice for patients with an abnormal heart and chronic ventricular dysrhythmia. In patients with a prolonged QT interval and in patients with a normal heart propranolol is the drug of choice. Propranolol should be used cautiously in patients with sick sinus syndrome, AV block or abnormal hemodynamics.