Polymorphic ventricular tachycardia in children

Polymorphic ventricular tachycardia (catecholaminergic) is a malignant arrhythmia caused by the presence of ventricular tachycardia of at least two morphologies and induced by physical exertion or by the administration of isoproterenol. It is accompanied by syncopal conditions, has a high risk of sudden arrhythmic death. The family variant of polymorphic catecholaminergic ventricular tachycardia is presumably considered a hereditary disease.

Symptoms of polymorphic ventricular tachycardia

Attacks of polymorphic ventricular tachycardia are provoked by emotional or physical stress, as well as by swimming. More than 30% of cases of syncope are accompanied by convulsions, which causes late diagnosis. These patients, as well as patients with CYH QT. Long stand on the account of a neurologist and receive anticonvulsant therapy. On the ECG, without an attack, bradycardia and normal Q-Tc values are usually recorded. The reaction to the stress test can be highly reproducible, and the test itself is the key in the diagnosis of the disease, since it is highly likely to provoke polymorphic tachycardia in this group. Patients typically have a progressive increase in arrhythmic symptoms - from a single monomorphic ventricular extrasystole to bigemia extrasystole and polymorphic ventricular tachycardia. In the absence of treatment, mortality in this disease is very high, it reaches 30-50% by the age of 30 years. At the same time, the earlier the clinical manifestation of the disease occurred, the higher the risk of sudden arrhythmic death.

Treatment of polymorphic ventricular tachycardia

Beta-blockers [nadolol, bisoprolol (concor), atenolol, propranolol] - an indispensable component of drug therapy for patients with polymorphic tachycardia. They significantly reduce the risk of sudden death. Doses of these drugs should be 2 times higher than those prescribed for patients with CYH QT. The most effective drug is nadolol. Often, one antiarrhythmic drug is not enough. As a rule, only combined antiarrhythmic therapy is effective in such patients. Another antiarrhythmic drug is added to the beta-blocker, taking into account its possible effect on triggering factors, such as supraventricular arrhythmias. As the 2nd antiarrhythmic drug in young people effective mexiletine at a dose of 5 mg / kg per day, lappakonitina hydrobromide at a dose of 1 mg / kg per day, propafenone at a dose of 5 mg / kg per day, amiodarone in a dose of 5-7 mg / kg per day, verapamil at a dose of 2 mg / kg per day or diethylaminopropionylethoxycarbonylaminophenothiazine (etatsizin) at a dose of 1-2 mg / kg per day. With anti-rhythmical purpose in complex therapy in children carbamazepine can be effective. Selection of an antiarrhythmic drug is carried out under the control of ECG and Holter monitoring data taking into account the doses of saturation. The maximum therapeutic effect of the drug is reasonable to calculate, taking into account what periods of the day the most pronounced ventricular tachycardia .. The exception is long-acting drugs and amiodarone. The maintenance dose of an antiarrhythmic drug is determined individually. With an increase in the duration of the Q-T interval by more than 25% of the initial class III drugs are canceled. Metabolic therapy includes antihypoxants and antioxidants. Also used are ACE inhibitors that improve hemodynamic parameters in chronic circulatory failure.

The development of syncope attacks on the background of therapy, a critical sinus bradycardia, limiting the possibility of subsequent antiarrhythmic therapy, and the preservation of a high risk of sudden arrhythmic death (estimated by the concentration of individual risk factors) - indications for interventional treatment. Implantation of a cardioverter-defibrillator is performed for children with syncopal variants of polymorphic ventricular tachycardia if antiarrhythmic therapy does not prevent the development of polymorphic ventricular tachycardia. When detecting trigger factors for the development of ventricular tachycardia, regimens of their control in implanted devices are connected (antitachi-cardiac stimulation, etc.). In cases of severe recurrent course of ventricular tachycardia, the question of the advisability of radiofrequency catheter ablation of the source of ventricular tachycardia or trigger arrhythmic zones should be discussed. Implantation is not carried out in patients with frequent episodes of ventricular tachycardia or with the development of frequent episodes of supraventricular arrhythmia with a high rhythm frequency (more than 200 per minute) in patients with ventricular tachycardia, since in this case unreasonable triggers of antiarrhythmic implanted device on supraventricular tachyarrhythmia are possible. In severe cases, it is necessary to make maximum use of all possible resources of antiarrhythmic therapy (the combined appointment is nauseous and mexiletine), in recent years, the effectiveness of left-sided sympathectomy has been proven.

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