[Arrhythmias in pregnancy. How and when to treat?].

Cardiac arrhythmias can develop during pregnancy. The risk of arrhythmias is relatively higher during labor and delivery. Potential factors that can promote arrhythmias in pregnancy or during labor and delivery, include the direct cardiac electrophysiological effects of hormones, changes in autonomic tone, hemodynamic perturbations, hypokalemia, and underlying heart disease. In this review, the basis for treatment of supraventricular and ventricular tachycardias are described. No drug therapy is usually needed for the management of supraventricular or ventricular premature beats, but potential stimulants, such as smoking, caffeine, and alcohol should be eliminated. In paroxysmal supraventricular tachycardia, vagal stimulation maneuvers should be attempted first. In pregnant women with atrial fibrillation, the goal of treatment is conversion to sinus rhythm by electrical cardioversion. Rate control can be achieved by a cardioselective beta-adrenergic blocker drug and/ or digoxin. Ventricular arrhythmias may occur in the pregnant women, specially when cardiomyopathy, congenital heart disease, valvular heart disease, or mitral valve prolapse exists. Electrical cardioversion or treatment with sotalol may be used (amiodarone is not safe for the fetus). Finally, in women with congenital long QT syndrome, beta-blocker therapy must be continued during pregnancy and postpartum period.